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</style><div class="thumb tmulti tright"><div class="thumbinner multiimageinner" style="width:413px;max-width:413px"><div class="trow"><div class="tsingle" style="width:207px;max-width:207px"><div class="thumbimage"><span typeof="mw:File"></span></div><div class="thumbcaption"><a href="Scute" title="Scute">Scutes</a> (left) and skeletal components (right) of a turtle's carapace. Scutes between the costal (= pleural) and marginals are called supramarginal.</div></div><div class="tsingle" style="width:202px;max-width:202px"><div class="thumbimage"><span typeof="mw:File"></span></div><div class="thumbcaption">Scutes (left) and skeletal components (right) of a turtle's plastron <a href="Pleurodira" title="Pleurodira">Pleurodires</a> have an extra scute known as the intergular. It is mostly absent in <a href="Cryptodira" title="Cryptodira">cryptodires</a>.</div></div></div></div></div>
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</style><table class="sidebar sidebar-collapse nomobile nowraplinks"><tbody><tr><td class="sidebar-pretitle">Part of a series related to</td></tr><tr><th class="sidebar-title-with-pretitle" style="background:#82C3D8; padding:0.2em; font-size:160%; font-weight:bold;"><a href="Biomineralization" title="Biomineralization"><span class="tmpl-colored-link" style="color: white; text-decoration: inherit;">Biomineralization</span></a></th></tr><tr><td class="sidebar-image"><span typeof="mw:File"></span></td></tr><tr><td class="sidebar-content">
<div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;font-size:100%;font-weight:bold;;color: var(--color-base)">General</div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist">
<ul><li><a href="Mineralized_tissues" title="Mineralized tissues">Mineralized tissues</a></li>
<li><a href="Remineralisation" title="Remineralisation">Remineralisation</a></li>
<li><a href="Biocrystallization" title="Biocrystallization">Biocrystallization</a></li>
<li><a href="Biointerface" title="Biointerface">Biointerface</a></li>
<li><a href="Biofilm" title="Biofilm">Biofilm</a></li></ul>
</div></div></div></td>
</tr><tr><td class="sidebar-content">
<div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;font-size:100%;font-weight:bold;;color: var(--color-base)"><a href="Exoskeleton" title="Exoskeleton">Exoskeletons</a> (shells)</div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist">
<ul><li>Arthropod
<ul><li><a href="Arthropod_exoskeleton" title="Arthropod exoskeleton">exoskeleton</a></li>
<li><a href="Arthropod_cuticle" class="mw-redirect" title="Arthropod cuticle">cuticle</a></li></ul></li>
<li><a href="Brachiopod#Shells_and_their_mechanisms" title="Brachiopod">Brachiopod shell</a></li>
<li><a href="Cephalopod#Shell" title="Cephalopod">Cephalopod shell</a>
<ul><li><a href="Cirrate_shell" title="Cirrate shell">cirrate shell</a></li>
<li><a href="Cuttlebone" title="Cuttlebone">cuttlebone</a></li>
<li><a href="Gladius_(cephalopod)" title="Gladius (cephalopod)">gladius</a></li></ul></li>
<li><a href="Lorica_(biology)" title="Lorica (biology)">Lorica</a>
<ul><li><a href="Choanoflagellate#Silicon_biomineralization" title="Choanoflagellate">Choanoflagellate lorica</a></li></ul></li>
<li><a href="Protist_shell" title="Protist shell">Protist shell</a>
<ul><li><a href="Coccolithophore#Coccolithophore_shells" title="Coccolithophore">coccosphere</a></li>
<li><a href="Coccolith" title="Coccolith">coccolith</a></li>
<li><a href="Frustule" title="Frustule">diatom frustule</a></li>
<li><a href="Foraminifera_test" title="Foraminifera test">foraminifera test</a></li>
<li><a href="Testate_amoebae" title="Testate amoebae">testate amoebae</a></li></ul></li>
<li><a href="Seashell" title="Seashell">Seashell</a>
<ul><li><a href="Stereom" title="Stereom">echinoderm stereom</a></li>
<li><a href="Mollusc_shell" title="Mollusc shell">mollusc shell</a>
<ul><li><a href="Nacre" title="Nacre">nacre</a></li>
<li><a href="Chiton#Shell" title="Chiton">chiton shell</a></li>
<li><a href="Gastropod_shell" title="Gastropod shell">gastropod shell</a></li></ul></li>
<li><a href="Small_shelly_fauna" title="Small shelly fauna">small shelly fauna</a></li>
<li><a href="Scaly-foot_gastropod#Shell" title="Scaly-foot gastropod">scaly-foot snail shell</a></li>
<li><a href="Shell_growth_in_estuaries" title="Shell growth in estuaries">estuary shells</a></li></ul></li>
<li><a href="Sponge_spicule" title="Sponge spicule">Sponge spicule</a></li>
<li><a href="Test_(biology)" title="Test (biology)">Test</a></li>
</ul>
</div></div></div></td>
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<div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;font-size:100%;font-weight:bold;;color: var(--color-base)"><a href="Endoskeleton" title="Endoskeleton">Endoskeletons</a> (<a href="Bone" title="Bone">bones</a>)</div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist">
<ul><li><a href="Skeleton#Vertebrates" title="Skeleton">Vertebrate skeleton</a></li>
<li><a href="Bone_mineral" title="Bone mineral">Bone mineral</a></li>
<li><a href="Ossification" title="Ossification">Ossification</a></li></ul>
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</tr><tr><td class="sidebar-content">
<div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;font-size:100%;font-weight:bold;;color: var(--color-base)">Teeth, scales, tusks etc</div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist">
<ul><li><a href="Limpet#Biomineralization" title="Limpet">Limpet teeth</a></li>
<li><a href="Otolith" title="Otolith">Otolith</a>
<ul><li><a href="Otolithic_membrane" title="Otolithic membrane">otolithic membrane</a></li></ul></li>
<li><a href="Scale_microfossils" title="Scale microfossils">Scale microfossils</a></li>
<li><a href="Tusk" title="Tusk">Tusk</a></li></ul>
</div></div></div></td>
</tr><tr><td class="sidebar-content">
<div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;font-size:100%;font-weight:bold;;color: var(--color-base)"><a href="Calcification" title="Calcification">Calcification</a></div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist">
<ul><li><a href="Amorphous_calcium_carbonate" title="Amorphous calcium carbonate">amorphous calcium carbonate</a></li>
<li><a href="Marine_biogenic_calcification" title="Marine biogenic calcification">marine biogenic calcification</a></li>
<li><a href="Calcareous_nannofossils" title="Calcareous nannofossils">calcareous nannofossils</a></li></ul>
</div>
<div class="hlist">
<ul><li><a href="Aragonite" title="Aragonite">Aragonite</a>
<ul><li><a href="Oolitic_aragonite_sand" title="Oolitic aragonite sand">oolitic aragonite sand</a></li>
<li><a href="Aragonite_sea" title="Aragonite sea">aragonite sea</a></li></ul></li></ul>
</div>
<div class="hlist">
<ul><li><a href="Calcite" title="Calcite">Calcite</a>
<ul><li><a href="Microbiologically_induced_calcite_precipitation" title="Microbiologically induced calcite precipitation">microbial calcite precipitation</a><br></li>
<li><a href="Calcite_sea" title="Calcite sea">calcite sea</a></li>
<li><a href="Great_Calcite_Belt" title="Great Calcite Belt">Great Calcite Belt</a></li></ul></li></ul>
</div></div></div></td>
</tr><tr><td class="sidebar-content">
<div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;font-size:100%;font-weight:bold;;color: var(--color-base)"><a href="Silicification" title="Silicification">Silicification</a></div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist">
<ul><li><a href="Biogenic_silica" title="Biogenic silica">biogenic silica</a></li>
<li><a href="Siliceous_ooze" title="Siliceous ooze">siliceous ooze</a></li>
<li><a href="Diatomaceous_earth" title="Diatomaceous earth">diatomaceous earth</a></li></ul>
</div></div></div></td>
</tr><tr><td class="sidebar-content">
<div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;font-size:100%;font-weight:bold;;color: var(--color-base)">Other forms</div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist">
<ul><li><a href="Bone_bed" title="Bone bed">Bone bed</a></li>
<li><a href="Kerogen" title="Kerogen">Kerogen</a>
<ul><li><a href="Alginite" title="Alginite">alginite</a></li>
<li><a href="Oil_shale" title="Oil shale">oil shale</a></li></ul></li>
<li><a href="Phosphate" title="Phosphate">Phosphate</a>
<ul><li><a href="Phosphorite" title="Phosphorite">phosphorite</a></li></ul></li>
<li><a href="Pyrena" title="Pyrena">Pyrena</a></li></ul>
</div></div></div></td>
</tr><tr><td class="sidebar-content">
<div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;font-size:100%;font-weight:bold;;color: var(--color-base)">Related</div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist">
<ul><li><a href="Mineral_evolution" title="Mineral evolution">Mineral evolution</a></li>
<li>In soil
<ul><li><a href="Mineralization_(soil_science)" title="Mineralization (soil science)">mineralization</a></li>
<li><a href="Immobilization_(soil_science)" title="Immobilization (soil science)">immobilization</a></li></ul></li>
<li><a href="Ballast_minerals" class="mw-redirect" title="Ballast minerals">Ballast minerals</a></li>
<li><a href="Magnetofossil" title="Magnetofossil">Magnetofossil</a></li>
<li><a href="Magnetosome" title="Magnetosome">Magnetosome</a></li>
<li><a href="Magnetotactic_bacteria" title="Magnetotactic bacteria">Magnetotactic bacteria</a></li>
<li><a href="Magnetoreception" title="Magnetoreception">Magnetoreception</a></li>
<li><a href="Microfossil" title="Microfossil">Microfossils</a></li>
<li><a href="Engrailed_(gene)" title="Engrailed (gene)"><i>engrailed</i> gene</a></li>
<li><a href="Druse_(botany)" title="Druse (botany)">Druse</a></li>
<li><i><a href="Cupriavidus_metallidurans" title="Cupriavidus metallidurans">Cupriavidus metallidurans</a></i></li>
<li><a href="Biomineralising_polychaete" title="Biomineralising polychaete">Biomineralising polychaetes</a></li>
<li><a href="Mineral_(nutrient)" title="Mineral (nutrient)">Mineral nutrients</a></li>
<li><a href="Microbial_mat" title="Microbial mat">Microbial mat</a></li>
<li><a href="Fossil#Fossilization_processes" title="Fossil">Fossilization</a>
<ul><li><a href="Permineralization" title="Permineralization">permineralization</a></li>
<li><a href="Petrifaction" title="Petrifaction">petrifaction</a></li></ul></li>
<li><a href="Burgess_Shale-type_preservation#Preservational_regime" title="Burgess Shale-type preservation">Burgess Shale preservation</a></li></ul>
</div></div></div></td>
</tr><tr><td class="sidebar-below hlist" style="background-color: #82C3D8; border-color: #A2B8BF">
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</style></td></tr></tbody></table>
<p>The <b>turtle shell</b> is a shield for the ventral and dorsal parts of <a href="Turtle" title="Turtle">turtles</a> (the <a href="Order_(biology)" title="Order (biology)">order</a> Testudines), completely enclosing all the turtle's vital organs and in some cases even the head.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> It is constructed of modified bony elements such as the ribs, parts of the pelvis, and other bones found in most reptiles. The bone of the shell consists of both skeletal and <a href="Dermal_bone" title="Dermal bone">dermal bone</a>, showing that the complete enclosure of the shell likely evolved by including dermal armor into the rib cage.
</p><p>The turtle's shell is important to study, not just because of the apparent protection it provides for the animal, but also as an identification tool, in particular with fossils, as the shell is one of the most likely parts of a turtle to survive fossilization. Therefore, understanding the shell structure in living species provides comparable material with fossils.
</p><p>The shell of the <a href="Hawksbill_turtle" class="mw-redirect" title="Hawksbill turtle">hawksbill turtle</a>, among other species, has been used as a material for a wide range of small decorative and practical items since antiquity, including food and medicine,<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> but is normally referred to as <a href="Tortoiseshell_material" class="mw-redirect" title="Tortoiseshell material">tortoiseshell</a>.
</p>
<meta property="mw:PageProp/toc">
<div class="mw-heading mw-heading2"><h2 id="Shell_nomenclature">Shell nomenclature</h2></div>
<p>The turtle shell is made up of numerous bony elements, generally named after similar bones in other vertebrates, and a series of <a href="Keratin" title="Keratin">keratinous</a> <a href="Scute" title="Scute">scutes</a> which are also uniquely named. The ventral surface is called the <i>plastron</i>.<sup id="cite_ref-rom56_3-0" class="reference"><a href="#cite_note-rom56-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-zang69_4-0" class="reference"><a href="#cite_note-zang69-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> These are joined by an area called the bridge. The actual suture between the bridge and the plastron is called the anterior bridge strut.<sup id="cite_ref-twg97_5-0" class="reference"><a href="#cite_note-twg97-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> In <a href="Pleurodira" title="Pleurodira">Pleurodires</a>, the posterior pelvis is also part of the <a href="Carapace" title="Carapace">carapace</a>, fully fused with it. This is not the case in <a href="Cryptodira" title="Cryptodira">Cryptodires</a>, which have a floating pelvis.<sup id="cite_ref-rom56_3-1" class="reference"><a href="#cite_note-rom56-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-zang69_4-1" class="reference"><a href="#cite_note-zang69-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> The anterior bridge strut and posterior bridge strut are part of the plastron. On the carapace are the sutures into which they insert, known as the Bridge carapace suture.<sup id="cite_ref-twg97_5-1" class="reference"><a href="#cite_note-twg97-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup>
</p><p>In the shell there is a <a href="Turtle" title="Turtle">turtle</a>'s <a href="Epidermis_(zoology)" title="Epidermis (zoology)">epidermis</a> layer. This layer is important to the strength of the shell surrounding it. In an international study, the layer can be as thick as two to four cells. Even with such a small thickness, the epidermis allows for the deformation the shell can experience and provides the shell more support.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> The epidermis layer is apparent in both sections of the shell—carapace and plastron—and is thicker in critical areas. A thicker epidermis allows a higher stress force to be experienced without permanent deformation or critical failure of the shell.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup>
</p><p>The shape of the shell is from its <a href="Evolution" title="Evolution">evolutionary</a> process, which caused many microstructures to appear to aid survival and motion. The shell shape allows the animal to escape predatory situations. Microstructures can include the scutes mentioned prior or the ribs found internally of the shell. Many ribs can be found within and throughout the shell. The rib structures provide extra structural support but allows the shell to deform elastically depending on the situation the <a href="Turtle" title="Turtle">turtle</a> is in (i.e., predatory escape).<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> Nonstructural mechanisms have also been in the turtle shell that aids the <a href="Turtle" title="Turtle">turtle</a> during <a href="Animal_locomotion" title="Animal locomotion">locomotion</a>. A mucus film covers parts of the shell, allowing some physical protection and also reducing <a href="Friction" title="Friction">friction</a> and <a href="Drag_(physics)" title="Drag (physics)">drag</a>.
</p><p>The bones of the shell are named for standard vertebrate elements. As such, the carapace is made up of eight pleurals on each side. These are a combination of the ribs and fused dermal bone. Outside of this, at the anterior of the shell, is the single nuchal bone, a series of twelve paired periphals then extend along each side. At the posterior of the shell is the pygal bone, and in front of this, nested behind the eighth pleurals, is the suprapygal.<sup id="cite_ref-rom56_3-2" class="reference"><a href="#cite_note-rom56-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>
</p>
<p>Between each of the pleurals are a series of neural bones,<sup id="cite_ref-pchp88_9-0" class="reference"><a href="#cite_note-pchp88-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> which although always present are not always visible,<sup id="cite_ref-tg96_10-0" class="reference"><a href="#cite_note-tg96-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> in many species of Pleurodire they are submerged below the pleurals.<sup id="cite_ref-rhmit77_11-0" class="reference"><a href="#cite_note-rhmit77-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> Beneath the neural bone is the neural arch which forms the upper half of the encasement for the spinal cord. Below this the rest of the vertebral column.<sup id="cite_ref-zang69_4-2" class="reference"><a href="#cite_note-zang69-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> Some species of turtles have some extra bones called mesoplastra, which are located between the carapace and plastron in the bridge area. They are present in most <a href="Pelomedusidae" title="Pelomedusidae">Pelomedusid</a> turtles.<sup id="cite_ref-pchpt84_12-0" class="reference"><a href="#cite_note-pchpt84-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup>
</p><p>The skeletal elements of the plastron are also largely in pairs. Anteriorly there are two epiplastra, with the hyoplastra behind them. These enclose the singular entoplastron. These make up the front half of the plastron and the hyoplastron contains the anterior bridge strut. The posterior half is made up of two hypoplastra (containing the posterior bridge strut) and the rear is a pair of xiphiplastra.<sup id="cite_ref-zang69_4-3" class="reference"><a href="#cite_note-zang69-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-twg97_5-2" class="reference"><a href="#cite_note-twg97-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup>
</p><p>Overlying the boney elements are a series of scutes, which are made of <a href="Keratin" title="Keratin">keratin</a> and are very similar to horn or nail tissue. In the center of the carapace are five vertebral scutes, and out from these are four pairs of costal scutes. Around the edge of the shell are 12 pairs of marginal scutes. All these scutes are aligned so that for the most part the sutures between the bones are in the middle of the scutes above. At the anterior of the shell there may be a cervical scute (sometimes incorrectly called a nuchal scute); however, the presence or absence of this scute is highly variable, even within species.<sup id="cite_ref-zang69_4-4" class="reference"><a href="#cite_note-zang69-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-pchpt84_12-1" class="reference"><a href="#cite_note-pchpt84-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup>
</p><p>
On the plastron there are two gular scutes at the front, followed by a pair of pectorals, then abdominals, femorals, and lastly anals. A particular variation is that the Pleurodiran turtles have an intergular scute between the gulars at the front, giving them a total of 13 plastral scutes, compared to the 12 in all Cryptodiran turtles.<sup id="cite_ref-zang69_4-5" class="reference"><a href="#cite_note-zang69-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-pchpt84_12-2" class="reference"><a href="#cite_note-pchpt84-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup></p><div style="clear:both;" class=""></div>
<div class="mw-heading mw-heading2"><h2 id="Carapace">Carapace</h2></div>
<p>The <a href="Carapace" title="Carapace">carapace</a> is the <a href="Dorsum_(biology)" class="mw-redirect" title="Dorsum (biology)">dorsal</a> (back), convex part of the shell structure of a <a href="Turtle" title="Turtle">turtle</a>, consisting of the animal's ossified ribs fused with the dermal bone. The <a href="Vertebral_column" class="mw-redirect" title="Vertebral column">spine</a> and expanded ribs are fused through ossification to <a href="Dermal_plate" class="mw-redirect" title="Dermal plate">dermal plates</a> beneath the skin to form a hard shell. Exterior to the skin, the shell is covered by <a href="Scutes" class="mw-redirect" title="Scutes">scutes</a>, which are horny plates made of <a href="Keratin" title="Keratin">keratin</a> that protect the shell from scrapes and bruises. A <i>keel</i>, a ridge that runs from front to the back of the animal, is present in some species. These may be single, paired, or even three rows. In most turtles, the shell is relatively uniform in structure, species variation in general shape and color being the main differences. However, the <a href="Trionychidae" title="Trionychidae">soft shell</a> turtles, <a href="Carettochelys_insculpta" class="mw-redirect" title="Carettochelys insculpta">pig-nose</a> turtles, and the <a href="Leatherback_sea_turtle" title="Leatherback sea turtle">leatherback sea turtle</a> have lost the scutes and reduced the ossification of the shell. This leaves the shell covered only by <a href="Skin" title="Skin">skin</a>.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> These are all highly aquatic forms.
</p><p>The evolution of the turtle's shell is unique because of how the carapace represents transformed vertebrae and ribs. While other tetrapods have their scapula, or <a href="Shoulder_blade" class="mw-redirect" title="Shoulder blade">shoulder blades</a>, found outside of the ribcage, the scapula for turtles is found inside the ribcage.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> The shells of other tetrapods, such as <a href="Armadillo" title="Armadillo">armadillos</a>, are not linked directly to the vertebral column or rib cage, allowing the ribs to move freely with the surrounding intercostal muscle.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> However, analysis of the transitional fossil <i><a href="Eunotosaurus_africanus" class="mw-redirect" title="Eunotosaurus africanus">Eunotosaurus africanus</a></i> shows that early ancestors of turtles lost that intercostal muscle usually found between the ribs.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="Plastron">Plastron</h2></div>
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</style><div role="note" class="hatnote navigation-not-searchable">"Plastron" redirects here. For the arthropod structural adaptation, see <a href="Gill#Plastrons" title="Gill">Gill § Plastrons</a>.</div>
<div class="thumb tmulti tnone center"><div class="thumbinner multiimageinner" style="width:362px;max-width:362px"><div class="trow"><div class="theader">Comparison of plastrons of a Cryptodire (<i><a href="Chrysemys_picta_marginata" class="mw-redirect" title="Chrysemys picta marginata">Chrysemys picta marginata</a></i>) and a Pleurodire (<i><a href="Chelodina_canni" title="Chelodina canni">Chelodina canni</a></i>)</div></div><div class="trow"><div class="tsingle" style="width:191px;max-width:191px"><div class="thumbimage"><span typeof="mw:File"></span></div><div class="thumbcaption">Plastral view of <i><a href="Chrysemys_picta_marginata" class="mw-redirect" title="Chrysemys picta marginata">Chrysemys picta marginata</a></i></div></div><div class="tsingle" style="width:167px;max-width:167px"><div class="thumbimage"><span typeof="mw:File"></span></div><div class="thumbcaption">Plastral view <i><a href="Chelodina_canni" title="Chelodina canni">Chelodina canni</a></i></div></div></div></div></div>
<p>The plastron (plural: plastrons or plastra) is the nearly flat part of the shell structure of a <a href="Turtle" title="Turtle">turtle</a>, what one would call the belly or ventral surface of the shell. It also includes within its structure the anterior and posterior bridge struts and the bridge of the shell.<sup id="cite_ref-zang69_4-6" class="reference"><a href="#cite_note-zang69-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-twg97_5-3" class="reference"><a href="#cite_note-twg97-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> The plastron is made up of nine bones and the two epiplastra at the anterior border of the plastron are homologous to the clavicles of other tetrapods.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> The rest of the plastral bones are homologous to the <a href="Gastralium" class="mw-redirect" title="Gastralium">gastralia</a> of other tetrapods. The plastron has been described as an <a href="Exoskeleton" title="Exoskeleton">exoskeleton</a>, like osteoderms of other reptilians; but unlike osteoderms, the plastron also possesses <a href="Osteoblast" title="Osteoblast">osteoblasts</a>, the <a href="Osteoid" title="Osteoid">osteoid</a>, and the <a href="Periosteum" title="Periosteum">periosteum</a>.<sup id="cite_ref-:5_20-0" class="reference"><a href="#cite_note-:5-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup>
</p><p>The evolution of the plastron has remained more mysterious, though Georges Cuvier, a French naturalist and zoologist in the 19th century, wrote that the plastron developed primarily from the sternum of the turtle.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> This fits well with the knowledge obtained through embryological studies, showing that changes in the pathways of rib development often result in malformation or loss of the plastron. This phenomenon occurs in turtle development, but instead of experiencing complete loss of the sternum, the turtle body plan repurposes the bone into the form of the plastron.<sup id="cite_ref-:3_22-0" class="reference"><a href="#cite_note-:3-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> However, other analyses find that the <a href="Endochondral_ossification" title="Endochondral ossification">endochondral</a> sternum is absent and replaced by the exoskeletal plastron. The ventral ribs are effectively not present, replaced by the plastron, unless the gastralia from which the plastron evolved were once floating ventral ribs.<sup id="cite_ref-:5_20-1" class="reference"><a href="#cite_note-:5-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> During turtle evolution, there was probably a division of labor between the ribs, which specialized to stabilize the trunk, and the abdominal muscles, which specialized for respiration; these changes took place 50 million years before the shell was fully ossified.<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup>
</p><p>The discovery of an ancestral turtle fossil, <i>Pappochelys rosinae,</i> provides additional clues as to how the plastron formed. <i>Pappochelys</i> serves as an intermediate form between two early stem-turtles, <i>E. africanus</i> and <i>Odontochelys,</i> the latter of which possesses a fully formed plastron. In place of a modern plastron, <i>Pappochelys</i> has paired gastralia, like those found in <i>E. africanus</i>. <i>Pappochelys</i> is different from its ancestor because the gastralia show signs of having once been fused, as indicated by the fossil specimens which show forked ends. This evidence shows a gradual change from paired gastralia, to paired and fused gastralia, and finally to the modern plastron across these three specimens.<sup id="cite_ref-:1_24-0" class="reference"><a href="#cite_note-:1-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup>
</p><p>In certain families there is a hinge between the <a href="https://en.wiktionary.org/wiki/pectoral" class="extiw external" title="wikt:pectoral">pectoral</a> and <a href="Abdominal" class="mw-redirect" title="Abdominal">abdominal</a> scutes allowing the turtle to almost completely enclose itself. In certain <a href="Species" title="Species">species</a> the sex of a testudine can be told by whether the plastron is <a href="https://en.wiktionary.org/wiki/concave" class="extiw external" title="wikt:concave">concave</a> (male) or <a href="https://en.wiktionary.org/wiki/convex" class="extiw external" title="wikt:convex">convex</a> (female). This is because of the mating position; the male's concave plastron allows it to more easily mount the female during copulation.
</p><p>The plastral scutes join along a central seam down the middle of the plastron. The relative lengths of the seam segments can be used to help identify a species of <a href="Turtle" title="Turtle">turtle</a>. There are six laterally symmetric pairs of scutes on the plastron: gular, humeral, pectoral, abdominal, femoral, and anal (going from the head to the tail down the seam); the abdominal and gular scute seams are approximately the same length, and the femoral and pectoral seams are approximately the same length.
</p><p>The <i>gular scute</i> or <i>gular projection</i> on a <a href="Turtle" title="Turtle">turtle</a> is the most anterior part of the plastron, the underside of the shell. Some tortoises have paired gular <a href="Scute" title="Scute">scutes</a>, while others have a single undivided gular scute. The gular scutes may be referred to as a gular projection if they stick out like a <a href="Trowel" title="Trowel">trowel</a>.
</p>
<div class="mw-heading mw-heading3"><h3 id="Plastral_formula">Plastral formula</h3></div>
<p>The plastral formula is used to compare the sizes of the individual plastral scutes (measured along the midseam). The following plastral scutes are often distinguished (with their abbreviation):
</p>
<dl><dd><table>
<tbody><tr>
<td>intergular</td>
<td>= intergul
</td></tr>
<tr>
<td>gular</td>
<td>= gul
</td></tr>
<tr>
<td>humeral</td>
<td>= hum
</td></tr>
<tr>
<td>pectoral</td>
<td>= pect
</td></tr>
<tr>
<td>abdominal</td>
<td>= abd
</td></tr>
<tr>
<td>femoral</td>
<td>= fem
</td></tr>
<tr>
<td>anal</td>
<td>= an
</td></tr></tbody></table></dd></dl>
<p>Comparison of the plastral formulas provides distinction between the two species. For example, for the <a href="Eastern_box_turtle" title="Eastern box turtle">eastern box turtle</a>, the plastral formula is: an > abd > gul > pect > hum >< fem.<sup id="cite_ref-NBIF1_25-0" class="reference"><a href="#cite_note-NBIF1-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup>
</p><p>Turtle plastrons were used by the ancient Chinese in a type of <a href="Divination" title="Divination">divination</a> called <a href="Plastromancy" class="mw-redirect" title="Plastromancy">plastromancy</a>.
</p>
<div class="mw-heading mw-heading2"><h2 id="Scutes">Scutes</h2></div>
<p>The turtle's shell is covered in <a href="Scute" title="Scute">scutes</a> that are made of <a href="Keratin" title="Keratin">keratin</a>. The individual scutes (as shown above) have specific names and are generally consistent across the various species of turtles. Terrestrial tortoises do not shed their scutes. New scutes grow by the addition of keratin layers to the base of each scute. Aquatic <a href="Turtle" title="Turtle">chelonii</a> shed individual scutes. The scute effectively forms the skin over the underlying bony structures; there is a very thin layer of subcutaneous tissue between the scute and the skeleton. The scutes can be brightly colored in some species, and turtle shells often follow <a href="Countershading" title="Countershading">Thayer's law</a> with carapace usually being a darker patterning than the plastron,<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> though there are exceptions.<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> Moustakas-Verho and Cherepanov's embryological study reveals that the patterning of the plastral scutes appear independent from the patterning of carapacial scutes, suggesting that the carapace and plastron evolved separately.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup>
</p><p>The appearance of scutes correlates to the transition from aquatic to terrestrial mode of life in tetrapods during the Carboniferous period (340 Ma).<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> In the evolution from amphibians to terrestrial amniotes, transition in a wide variety of skin structures occurred. Ancestors of turtles likely diverged from amphibians to develop a horny cover in their early terrestrial ancestral forms.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup>
</p>
<table class="wikitable">
<caption>Names of epidermal scutes in turtle shells
</caption>
<tbody><tr>
<th>Boulenger 1889<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup>
</th>
<th>Carr 1952<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup>
</th>
<th>Zangerl 1969<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup>
</th>
<th>Pritchard 1979<sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup>
</th></tr>
<tr>
<td>nuchal
</td>
<td>precentral
</td>
<td>cervical
</td>
<td>nuchal
</td></tr>
<tr>
<td>vertebral
</td>
<td>central
</td>
<td>vertebral
</td>
<td>central
</td></tr>
<tr>
<td>costal
</td>
<td>lateral
</td>
<td>pleural
</td>
<td>costal
</td></tr>
<tr>
<td>marginal
</td>
<td>marginal
</td>
<td>marginal
</td>
<td>marginal
</td></tr>
<tr>
<td>supracaudal
</td>
<td>postcentral
</td>
<td>12th marginal
</td>
<td>supracaudal
</td></tr>
<tr>
<td>intergular
</td>
<td>-
</td>
<td>intergular
</td>
<td>intergular
</td></tr>
<tr>
<td>(extra-) gular
</td>
<td>gular
</td>
<td>gular
</td>
<td>gular
</td></tr>
<tr>
<td>humeral
</td>
<td>humeral
</td>
<td>humeral
</td>
<td>humeral
</td></tr>
<tr>
<td>pectoral
</td>
<td>pectoral
</td>
<td>pectoral
</td>
<td>pectoral
</td></tr>
<tr>
<td>abdominal
</td>
<td>abdominal
</td>
<td>abdominal
</td>
<td>abdominal
</td></tr>
<tr>
<td>femoral
</td>
<td>femoral
</td>
<td>femoral
</td>
<td>femoral
</td></tr>
<tr>
<td>anal
</td>
<td>anal
</td>
<td>anal
</td>
<td>anal
</td></tr></tbody></table>
<div class="mw-heading mw-heading2"><h2 id="Ontogeny">Ontogeny</h2></div>
<p>The carapacial ridge plays an essential role in the development of the turtle shell. Embryological analyses show that the carapacial ridge initiates the formation of the turtle shell.<sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> It causes axial arrest which causes the ribs to be dorsalized, the shoulder girdle to be rearranged and encapsulated in the rib cage, and the carapace to develop.<sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> <i><a href="Odontochelys_semitestacea" class="mw-redirect" title="Odontochelys semitestacea">Odontochelys semitestacea</a></i> presents evidence of axial arrest that is observed in embryos but lacks fan-shaped ribs and a carapace. This suggests that the primitive carapacial ridge functioned differently and must have gained the function of mediating the ribs and carapace development later.<sup id="cite_ref-Kuratani_2011_38-0" class="reference"><a href="#cite_note-Kuratani_2011-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-:3_22-1" class="reference"><a href="#cite_note-:3-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> The <i><a href="PAX1" title="PAX1">PAX1</a></i> and <i><a href="Sonic_hedgehog" class="mw-redirect" title="Sonic hedgehog">Sonic hedgehog</a> gene</i> (<i>SHH</i>) serve as key regulators during the development of the vertebral column. <i>SHH</i> expression in the neural tube is essential for the maintenance of <i>PAX1</i> expression in the ventral sclerotome and thus plays a key role in carapacial rib development. Genetic observations of <i>PAX1</i> and <i>SHH</i> further provide an understanding in key gene expression that could potentially be responsible for changing turtle morphology.<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup>
</p><p>During the development of the turtle <a href="Embryo" title="Embryo">embryo</a>, the ribs grow sideways into the carapacial ridge, unique to turtles, entering the <a href="Dermis" title="Dermis">dermis</a> of the back to support the carapace. The development is signalled locally by <a href="Fibroblast_growth_factor" title="Fibroblast growth factor">fibroblast growth factors</a> including <a href="FGF10" title="FGF10">FGF10</a>.<sup id="cite_ref-Cebra-Thomas_Tan_2005_35-1" class="reference"><a href="#cite_note-Cebra-Thomas_Tan_2005-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="Evolutionary_origin">Evolutionary origin</h2></div>
<div class="mw-heading mw-heading3"><h3 id="Bony_dermal_plates_theory:_the_"Polka_Dot_Ancestor"">Bony dermal plates theory: the "Polka Dot Ancestor"</h3></div>
<p>Zoologists have sought to explain the evolutionary origin of the turtles, and in particular of their unique carapace. In 1914, J. Versluys proposed that bony plates in the dermis, <a href="Osteoderm" title="Osteoderm">osteoderms</a>, fused first to each other and then to the ribs beneath them. The theory persisted into the 21st century, when Olivier Rieppel proposed a hypothetical turtle precursor, its back covered by bony armour plates in the dermis, which he called the "Polka Dot Ancestor".<sup id="cite_ref-Schoch_Sues_2019_40-0" class="reference"><a href="#cite_note-Schoch_Sues_2019-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup> Michael Lee proposed that the transformation of the carapace began with an unarmoured parareptile and then an armoured pareiasaur, and ended with modern turtles with a fully developed carapace and a relocated rib cage.<sup id="cite_ref-Lee_1996_42-0" class="reference"><a href="#cite_note-Lee_1996-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> The theory accounted for the evolution of fossil pareisaurs from <i><a href="Bradysaurus" title="Bradysaurus">Bradysaurus</a></i> to <i><a href="Anthodon_(reptile)" title="Anthodon (reptile)">Anthodon</a></i>, but not for how the ribs could have become attached to the bony dermal plates.<sup id="cite_ref-Schoch_Sues_2019_40-1" class="reference"><a href="#cite_note-Schoch_Sues_2019-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading3"><h3 id="Broadened_ribs_theory">Broadened ribs theory</h3></div>
<div class="mw-heading mw-heading4"><h4 id="Permian:_first_stem-turtles">Permian: first stem-turtles</h4></div>
<p>Recent stem-turtle fossil discoveries provide a "comprehensive scenario" of the evolution of the turtle's shell. A fossil that may be a stem-turtle from the <a href="Permian" title="Permian">Permian</a> of South Africa, <i><a href="Eunotosaurus" title="Eunotosaurus">Eunotosaurus</a></i>, some 260 million years ago, had a short broad trunk, and a body-case of broadened and somewhat overlapping ribs, suggesting an early stage in the acquisition of a shell.<sup id="cite_ref-Schoch_Sues_2019_40-3" class="reference"><a href="#cite_note-Schoch_Sues_2019-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> The fossil has been called "a diapsid reptile in the process of becoming secondarily anapsid".<sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup> Olivier Rieppel summarizes the phylogenetic origins of the ancestral turtles: "<i>Eunotosaurus</i> is placed at the bottom of the stem section of the turtle tree, followed by <i>Pappochelys</i> and <i>Odontochelys</i> along the turtle stem and on to more crown-ward turtles".<sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup>
</p><p>Tyler Lyson and colleagues suggest that <i>Eunotosaurus</i> might imply a <a href="Fossorial" title="Fossorial">fossorial</a> origin for the turtles. During the Permian, the broadened ribs may have provided great stability in burrowing, giving a body shape resembling the extant fossorial <a href="Gopher_tortoise" title="Gopher tortoise">gopher tortoise</a>, with strong shoulders and forelimbs, and increased muscle attachment structures such as their tubercle on the posterior coracoid and their large and wide terminal phalanges creating shovel-like "hands". Fossoriality may have helped <i>Eunotosaurus</i> survive the global mass extinction at the end of the Permian period, and could have played an essential role in the early evolution of shelled turtles.<sup id="cite_ref-Lyson_Rubidge_Scheyer_2016_45-0" class="reference"><a href="#cite_note-Lyson_Rubidge_Scheyer_2016-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Chen_Benton_2012_46-0" class="reference"><a href="#cite_note-Chen_Benton_2012-46"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading4"><h4 id="Triassic:_evolution_of_complete_shell">Triassic: evolution of complete shell</h4></div>
<p>A stem-turtle from the Middle <a href="Triassic" title="Triassic">Triassic</a> of Germany, some 240 million years ago, <i><a href="Pappochelys" title="Pappochelys">Pappochelys</a></i>, has more distinctly broadened ribs, T-shaped in cross-section.<sup id="cite_ref-Schoch_Sues_2019_40-4" class="reference"><a href="#cite_note-Schoch_Sues_2019-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> They vary in shape along the spine.<sup id="cite_ref-Schoch_Sues_2015_47-0" class="reference"><a href="#cite_note-Schoch_Sues_2015-47"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup>
</p><p>A Late Triassic stem-turtle from <a href="Guizhou" title="Guizhou">Guizhou</a>, China, <i><a href="Eorhynchochelys" title="Eorhynchochelys">Eorhynchochelys</a></i>, is a much larger animal, up to 1.8 metres (5.9 ft) long, with a long tail and broadened but not overlapping ribs. Like the earlier fossils, it has small teeth.<sup id="cite_ref-Schoch_Sues_2019_40-5" class="reference"><a href="#cite_note-Schoch_Sues_2019-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup>
</p><p>Also in the Late Triassic, some 220 million years ago, the freshwater <i><a href="Odontochelys_semitestacea" class="mw-redirect" title="Odontochelys semitestacea">Odontochelys semitestacea</a></i> of <a href="Guangling_District" class="mw-redirect" title="Guangling District">Guangling</a> in southwest China has a partial shell, consisting of a complete bony plastron and an incomplete carapace.<sup id="cite_ref-Li-etal_48-0" class="reference"><a href="#cite_note-Li-etal-48"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Kuratani_2011_38-1" class="reference"><a href="#cite_note-Kuratani_2011-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> The fossil showed that the plastron evolved before the carapace.<sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup> Like crown turtles, it lacked intercostal muscles, so rib mobility was limited. The ribs were laterally expanded and broadened without ossification, like the embryos of modern turtles.<sup id="cite_ref-Li_Wu_Rieppel_2008_50-0" class="reference"><a href="#cite_note-Li_Wu_Rieppel_2008-50"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup>
</p><p>The development of a shell reaches completion with the late Triassic <i><a href="Proganochelys" title="Proganochelys">Proganochelys</a></i> of Germany and Thailand.<sup id="cite_ref-Li_Wu_Rieppel_2008_50-1" class="reference"><a href="#cite_note-Li_Wu_Rieppel_2008-50"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup> It lacked the ability to pull its head into its shell, and had a long neck and a long, spiked tail ending in a club, somewhat like an <a href="Ankylosaur" class="mw-redirect" title="Ankylosaur">ankylosaur</a>.<sup id="cite_ref-52" class="reference"><a href="#cite_note-52"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="Diseases">Diseases</h2></div>
<div class="mw-heading mw-heading3"><h3 id="Shell_rot">Shell rot</h3></div>
<p>
</p><p>Septicemic cutaneous ulcerative disease (SCUD) or "shell rot" causes ulceration of the shell.<sup id="cite_ref-kap57_53-0" class="reference"><a href="#cite_note-kap57-53"><span class="cite-bracket">[</span>53<span class="cite-bracket">]</span></a></sup> This is caused by <a href="Bacteria" title="Bacteria">bacteria</a> or <a href="Fungi" class="mw-redirect" title="Fungi">fungi</a> entering through an <a href="Abrasion_(medical)" class="mw-redirect" title="Abrasion (medical)">abrasion</a>, and poor <a href="Animal_husbandry" title="Animal husbandry">animal husbandry</a>. The disease progresses to a septicemic infection causing the degradation of the liver and other organs.<sup id="cite_ref-mad06_54-0" class="reference"><a href="#cite_note-mad06-54"><span class="cite-bracket">[</span>54<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading3"><h3 id="Pyramiding">Pyramiding</h3></div>
<p>Pyramiding is a shell deformity of captive <a href="Tortoise" title="Tortoise">tortoises</a> in which the shell grows unevenly, resulting in a <a href="Pyramid_(geometry)" title="Pyramid (geometry)">pyramid</a> shape underlying each scute. Factors which may contribute to pyramiding include inadequate water supply; the consumption of excessive animal or vegetable <a href="Protein" title="Protein">protein</a>; inadequate <a href="Calcium" title="Calcium">calcium</a>, <a href="UVB" class="mw-redirect" title="UVB">UVB</a>, and/or <a href="Vitamin_D3" class="mw-redirect" title="Vitamin D3">vitamin D3</a>; and poor nutrition.<sup id="cite_ref-55" class="reference"><a href="#cite_note-55"><span class="cite-bracket">[</span>55<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-56" class="reference"><a href="#cite_note-56"><span class="cite-bracket">[</span>56<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Fife_57-0" class="reference"><a href="#cite_note-Fife-57"><span class="cite-bracket">[</span>57<span class="cite-bracket">]</span></a></sup> Tortoise breeder Richard Fife documents that his wife raised two groups of <a href="Red-foot_tortoise" class="mw-redirect" title="Red-foot tortoise">red-foot tortoise</a> hatchlings, with identical diets over a number of months, but with different environmental moisture. The group raised in low humidity showed pyramiding, whereas the group raised in high humidity did not and had shells identical to wild tortoises. They found the same results with several other species.<sup id="cite_ref-Fife_57-1" class="reference"><a href="#cite_note-Fife-57"><span class="cite-bracket">[</span>57<span class="cite-bracket">]</span></a></sup> Researchers C.S. Wiesner and C. Iben also found that dry conditions during the first five months of growth in <a href="African_spurred_tortoise" title="African spurred tortoise">African spurred tortoises</a> produced taller humps than humid conditions, although dietary protein also had a minor effect.<sup id="cite_ref-Wiesner_58-0" class="reference"><a href="#cite_note-Wiesner-58"><span class="cite-bracket">[</span>58<span class="cite-bracket">]</span></a></sup>
</p>
<ul class="gallery mw-gallery-packed">
<li class="gallerybox" style="width: 152px">
<div class="thumb" style="width: 150px;"><span typeof="mw:File"></span></div>
<div class="gallerytext">Plastron of wild male <a href="Hermann's_tortoise" title="Hermann's tortoise">Hermann's tortoise</a> with ongoing shell rot (circled in red) and scars from previous shell rot (circled in black)</div>
</li>
<li class="gallerybox" style="width: 285.33333333333px">
<div class="thumb" style="width: 283.33333333333px;"><span typeof="mw:File"></span></div>
<div class="gallerytext">A <a href="Gopher_tortoise" title="Gopher tortoise">gopher tortoise</a> with severe pyramiding</div>
</li>
</ul>
<div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div>
<ul><li><a href="Evolutionary_developmental_biology" title="Evolutionary developmental biology">Evolutionary developmental biology</a></li>
<li><a href="Oracle_bone" title="Oracle bone">Oracle bone</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
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<ol class="references">
<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">
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.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}
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<li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text"><cite id="CITEREFLiWuRieppelWang2008" class="citation journal cs1">Li, Chun; Wu, Xiao-Chun; Rieppel, Olivier; Wang, Li-Ting; Zhao, Li-Jun (2008-11-27). <a rel="nofollow" class="external text" href="http://doc.rero.ch/record/16585/files/PAL_E2289.pdf">"An ancestral turtle from the Late Triassic of southwestern China"</a> <span class="cs1-format">(PDF)</span>. <i>Nature</i>. <b>456</b> (7221): <span class="nowrap">497–</span>501. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2008Natur.456..497L">2008Natur.456..497L</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature07533">10.1038/nature07533</a>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0028-0836">0028-0836</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19037315">19037315</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4405644">4405644</a>.</cite></span>
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<li id="cite_note-Li_Wu_Rieppel_2008-50"><span class="mw-cite-backlink">^ <a href="#cite_ref-Li_Wu_Rieppel_2008_50-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Li_Wu_Rieppel_2008_50-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFLiWuRieppelWang2008" class="citation journal cs1">Li, C.; Wu, X.-C.; Rieppel, O.; Wang, L.-T.; Zhao, L.-J. (2008). <a rel="nofollow" class="external text" href="http://doc.rero.ch/record/16585/files/PAL_E2289.pdf">"An ancestral turtle from the Late Triassic of southwestern China"</a> <span class="cs1-format">(PDF)</span>. <i>Nature</i>. <b>456</b> (7221): <span class="nowrap">497–</span>501. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2008Natur.456..497L">2008Natur.456..497L</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature07533">10.1038/nature07533</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19037315">19037315</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4405644">4405644</a>.</cite></span>
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<li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</a></b></span> <span class="reference-text"><cite id="CITEREFGaffney,_Eugene_S.1990" class="citation book cs1">Gaffney, Eugene S. (1990). <i>The comparative osteology of the Triassic turtle </i>Proganochelys<i></i>. <a href="OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/263164288">263164288</a>.</cite></span>
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<li id="cite_note-52"><span class="mw-cite-backlink"><b><a href="#cite_ref-52">^</a></b></span> <span class="reference-text"><cite id="CITEREFAsherSpencer_G.KleinLovelace2018" class="citation journal cs1">Asher, J. Lichtig; Spencer G., Lucas; Klein, Hendrik; Lovelace, David M. (2018). "Triassic turtle tracks and the origin of turtles". <i>Historical Biology</i>. <b>30</b> (8): <span class="nowrap">1112–</span>1122. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F08912963.2017.1339037">10.1080/08912963.2017.1339037</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:133893011">133893011</a>.</cite></span>
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<li id="cite_note-kap57-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-kap57_53-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFKaplan,_H._M.1957" class="citation journal cs1">Kaplan, H. M. (1957). "Septicemic, cutaneous ulcerative disease of turtles". <i>Proc. Animal Care Panel</i>. <b>7</b>: <span class="nowrap">273–</span>277.</cite></span>
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<li id="cite_note-mad06-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-mad06_54-0">^</a></b></span> <span class="reference-text">Mader, D. (2006) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=7Ai4BKhi0VUC">Reptile Medicine and Surgery</a>, 2nd ed., Saunders, <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>072169327X</bdi>.</span>
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<li id="cite_note-55"><span class="mw-cite-backlink"><b><a href="#cite_ref-55">^</a></b></span> <span class="reference-text"><cite id="CITEREFGerlach2004" class="citation web cs1">Gerlach, J (2004). <a rel="nofollow" class="external text" href="https://islandbiodiversity.com/Afr%20J%20Herpetol%202004%20tortoise%20diet.pdf">"Effects of diet on the systematic utility of the tortoise carapace"</a> <span class="cs1-format">(PDF)</span>. <i>Island Biodiversity</i>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20211201083728/http://islandbiodiversity.com/Afr%20J%20Herpetol%202004%20tortoise%20diet.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 1 December 2021<span class="reference-accessdate">. Retrieved <span class="nowrap">17 July</span> 2019</span>.</cite></span>
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<li id="cite_note-56"><span class="mw-cite-backlink"><b><a href="#cite_ref-56">^</a></b></span> <span class="reference-text"><cite id="CITEREFInnis" class="citation web cs1">Innis, Charles. <a rel="nofollow" class="external text" href="https://www.cabi.org/isc/FullTextPDF/2009/20093019006.pdf">"BASIC HUSBANDRY AND NUTRITION OF CHELONIANS"</a> <span class="cs1-format">(PDF)</span>. <i>Cabi.Org</i>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20190717120448/https://www.cabi.org/isc/FullTextPDF/2009/20093019006.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2019-07-17<span class="reference-accessdate">. Retrieved <span class="nowrap">2019-07-17</span></span>.</cite></span>
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<li id="cite_note-Fife-57"><span class="mw-cite-backlink">^ <a href="#cite_ref-Fife_57-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Fife_57-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFFife2014" class="citation web cs1">Fife, Richard (23 January 2014). <a rel="nofollow" class="external text" href="http://www.reptilesmagazine.com/Turtles-Tortoises/Turtle-Care/Pyramiding-in-Tortoises/">"Pyramiding in Tortoises"</a>. <i>Reptiles</i>. Reptiles Magazine.</cite></span>
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<li id="cite_note-Wiesner-58"><span class="mw-cite-backlink"><b><a href="#cite_ref-Wiesner_58-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFWiesnerIben2003" class="citation journal cs1">Wiesner, C S; Iben, C (February 2003). "Influence of environmental humidity and dietary protein on pyramidal growth of carapaces in African spurred tortoises (Geochelone sulcata)". <i>J Anim Physiol Anim Nutr (Berl)</i>. <b>87</b> (<span class="nowrap">1–</span>2): <span class="nowrap">66–</span>74. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1046%2Fj.1439-0396.2003.00411.x">10.1046/j.1439-0396.2003.00411.x</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/14511150">14511150</a>.</cite></span>
</li>
</ol></div>
<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>
<ul><li><a rel="nofollow" class="external text" href="http://africantortoise.com/pyramiding_in_tortoises.htm">African Tortoise Website</a>, has more information on pyramiding</li>
<li><a rel="nofollow" class="external text" href="https://www.newscientist.com/article/dn17442-embryo-origami-gives-the-turtle-its-shell.html"><i>New Scientist</i> article (including video) on how the turtle evolved its shell</a></li></ul>
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</style></div><div role="navigation" class="navbox" aria-labelledby="Turtle_terminology18" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Turtle_terminology18" style="font-size:114%;margin:0 4em">Turtle terminology</div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Carapace" title="Carapace">Carapace</a></li>
<li><a href="Chelonitoxism" title="Chelonitoxism">Chelonitoxism</a></li>
<li><a href="Turtle_fibropapillomatosis" title="Turtle fibropapillomatosis">Fibropapillomatosis</a></li>
<li><a class="mw-selflink-fragment" href="#Plastron">Gular scute</a></li>
<li><a href="Jackson_ratio" title="Jackson ratio">Jackson ratio</a></li>
<li><a class="mw-selflink-fragment" href="#Plastron">Plastron</a></li>
<li><a class="mw-selflink-fragment" href="#Pyramiding">Pyramiding</a></li>
<li><a href="Tortoiseshell" title="Tortoiseshell">Tortoiseshell</a></li></ul>
</div></td></tr></tbody></table></div>
<div class="navbox-styles"></div><div role="navigation" class="navbox" aria-labelledby="Testudines566" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Testudines566" style="font-size:114%;margin:0 4em"><a href="Turtle" title="Turtle">Testudines</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div>
<ul><li>Kingdom: <a href="Animal" title="Animal">Animalia</a></li>
<li>Phylum: <a href="Chordate" title="Chordate">Chordata</a></li>
<li>Class: <a href="Reptile" title="Reptile">Reptilia</a></li>
<li><i>Clade</i>: <a href="Diapsid" title="Diapsid">Diapsida</a></li>
<li>Order: <a href="Turtle" title="Turtle">Testudines</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="Order_(biology)#Hierarchy_of_ranks" title="Order (biology)">Suborder</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Superfamily30" scope="row" class="navbox-group" style="width:10em"><a href="Taxonomic_rank" title="Taxonomic rank">Superfamily</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Family38" scope="row" class="navbox-group" style="width:11em"><a href="List_of_Testudines_families" title="List of Testudines families">Family</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td class="navbox-abovebelow" colspan="2" style="text-align:left;"><div id="Genus15"><b><a href="Genus" title="Genus">Genus</a></b></div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="Cryptodira" title="Cryptodira">Cryptodira</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em"><a href="Sea_turtle" title="Sea turtle">Chelonioidea</a><br>(Sea turtles)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Cheloniidae39" scope="row" class="navbox-group" style="width:11em"><a href="Cheloniidae" title="Cheloniidae">Cheloniidae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Allopleuron" title="Allopleuron">Allopleuron</a></i></li>
<li><i><a href="Loggerhead_sea_turtle" title="Loggerhead sea turtle">Caretta</a></i></li>
<li>†<i><a href="Carolinochelys" title="Carolinochelys">Carolinochelys</a></i></li>
<li><i><a href="Green_sea_turtle" title="Green sea turtle">Chelonia</a></i></li>
<li>†<i><a href="Eochelone" title="Eochelone">Eochelone</a></i></li>
<li><i><a href="Hawksbill_sea_turtle" title="Hawksbill sea turtle">Eretmochelys</a></i></li>
<li>†<i><a href="Gigantatypus" title="Gigantatypus">Gigantatypus</a></i></li>
<li>†<i><a href="Glarichelys" title="Glarichelys">Glarichelys</a></i></li>
<li>†<i><a href="Itilochelys" title="Itilochelys">Itilochelys</a></i></li>
<li><i><a href="Ridley_sea_turtle" title="Ridley sea turtle">Lepidochelys</a></i></li>
<li>†<i><a href="Mexichelys" title="Mexichelys">Mexichelys</a></i></li>
<li>†<i><a href="Miocaretta" title="Miocaretta">Miocaretta</a></i></li>
<li><i><a href="Flatback_sea_turtle" title="Flatback sea turtle">Natator</a></i></li>
<li>†<i><a href="Pacifichelys" title="Pacifichelys">Pacifichelys</a></i></li>
<li>†<i><a href="Syllomus" title="Syllomus">Syllomus</a></i></li>
<li>†<i><a href="Tasbacka" title="Tasbacka">Tasbacka</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Dermochelyidae" title="Dermochelyidae">Dermochelyidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Arabemys" title="Arabemys">Arabemys</a></i></li>
<li>†<i><a href="Corsochelys" title="Corsochelys">Corsochelys</a></i></li>
<li>†<i><a href="Cosmochelys" title="Cosmochelys">Cosmochelys</a></i></li>
<li><i><a href="Leatherback_sea_turtle" title="Leatherback sea turtle">Dermochelys</a></i></li>
<li>†<i><a href="Eosphargis" title="Eosphargis">Eosphargis</a></i></li>
<li>†<i><a href="Mesodermochelys" title="Mesodermochelys">Mesodermochelys</a></i></li>
<li>†<i><a href="Psephophorus" title="Psephophorus">Psephophorus</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"> </th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Euclastes" title="Euclastes">Euclastes</a></i></li>
<li>†<i><a href="Peritresius" title="Peritresius">Peritresius</a></i></li>
<li>†<i><a href="Procolpochelys" title="Procolpochelys">Procolpochelys</a></i></li>
<li>†<i><a href="Protosphargis" title="Protosphargis">Protosphargis</a></i></li>
<li>†<i><a href="Puppigerus" title="Puppigerus">Puppigerus</a></i></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em"><a href="Kinosternoidea" title="Kinosternoidea">Kinosternoidea</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Dermatemydidae35" scope="row" class="navbox-group" style="width:11em"><a href="Dermatemydidae" title="Dermatemydidae">Dermatemydidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="Hickatee" title="Hickatee">Dermatemys</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Kinosternidae" title="Kinosternidae">Kinosternidae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="Narrow-bridged_musk_turtle" title="Narrow-bridged musk turtle">Claudius</a></i></li>
<li>†<i><a href="Hoplochelys" title="Hoplochelys">Hoplochelys</a></i></li>
<li><i><a href="Kinosternon" title="Kinosternon">Kinosternon</a></i></li>
<li><i><a href="Staurotypus" title="Staurotypus">Staurotypus</a></i></li>
<li><i><a href="Sternotherus" title="Sternotherus">Sternotherus</a></i></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em"><a href="Testudinoidea" title="Testudinoidea">Testudinoidea</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Emydidae" title="Emydidae">Emydidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Acherontemys" title="Acherontemys">Acherontemys</a></i></li>
<li><i><a href="Chrysemys" title="Chrysemys">Chrysemys</a></i></li>
<li><i><a href="Clemmys" title="Clemmys">Clemmys</a></i></li>
<li><i><a href="Deirochelys" title="Deirochelys">Deirochelys</a></i></li>
<li><i><a href="Emys" title="Emys">Emys</a></i></li>
<li><i><a href="Actinemys" title="Actinemys">Actinemys</a></i></li>
<li><i><a href="Emydoidea" class="mw-redirect" title="Emydoidea">Emydoidea</a></i></li>
<li><i><a href="Glyptemys" title="Glyptemys">Glyptemys</a></i></li>
<li><i><a href="Graptemys" title="Graptemys">Graptemys</a></i></li>
<li><i><a href="Diamondback_terrapin" title="Diamondback terrapin">Malaclemys</a></i></li>
<li><i><a href="Pseudemys" title="Pseudemys">Pseudemys</a></i></li>
<li><i><a href="Box_turtle" title="Box turtle">Terrapene</a></i></li>
<li><i><a href="Trachemys" title="Trachemys">Trachemys</a></i></li>
<li>†<i>Wilburemys</i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Geoemydidae" title="Geoemydidae">Geoemydidae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="Batagur" title="Batagur">Batagur</a></i></li>
<li>†<i><a href="Banhxeochelys" title="Banhxeochelys">Banhxeochelys</a></i></li>
<li><i><a href="Asian_box_turtle" title="Asian box turtle">Cuora</a></i></li>
<li><i><a href="Cyclemys" title="Cyclemys">Cyclemys</a></i></li>
<li><i><a href="Black_pond_turtle" title="Black pond turtle">Geoclemys</a></i></li>
<li><i><a href="Geoemyda" title="Geoemyda">Geoemyda</a></i></li>
<li><i><a href="Brahminy_river_turtle" title="Brahminy river turtle">Hardella</a></i></li>
<li><i><a href="Heosemys" title="Heosemys">Heosemys</a></i></li>
<li><i><a href="Sulawesi_forest_turtle" title="Sulawesi forest turtle">Leucocephalon</a></i></li>
<li><i><a href="Malayemys" title="Malayemys">Malayemys</a></i></li>
<li><i><a href="Mauremys" title="Mauremys">Mauremys</a></i></li>
<li><i><a href="Melanochelys" title="Melanochelys">Melanochelys</a></i></li>
<li><i><a href="Morenia" title="Morenia">Morenia</a></i></li>
<li><i><a href="Malayan_flat-shelled_turtle" title="Malayan flat-shelled turtle">Notochelys</a></i></li>
<li><i><a href="Malaysian_giant_turtle" title="Malaysian giant turtle">Orlitia</a></i></li>
<li><i><a href="Pangshura" title="Pangshura">Pangshura</a></i></li>
<li><i><a href="Rhinoclemmys" title="Rhinoclemmys">Rhinoclemmys</a></i></li>
<li><i><a href="Sacalia" title="Sacalia">Sacalia</a></i></li>
<li><i><a href="Siebenrockiella" title="Siebenrockiella">Siebenrockiella</a></i></li>
<li><i><a href="Cane_turtle" title="Cane turtle">Vijayachelys</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"> <a href="Big-headed_turtle" title="Big-headed turtle">Platysternidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="Big-headed_turtle" title="Big-headed turtle">Platysternon</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Tortoise" title="Tortoise">Testudinidae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="Aldabrachelys" title="Aldabrachelys">Aldabrachelys</a></i></li>
<li><i><a href="Astrochelys" title="Astrochelys">Astrochelys</a></i></li>
<li><i><a href="Centrochelys" title="Centrochelys">Centrochelys</a></i></li>
<li><i><a href="Chelonoidis" title="Chelonoidis">Chelonoidis</a></i></li>
<li><i><a href="Angulate_tortoise" title="Angulate tortoise">Chersina</a></i></li>
<li><i><a href="Cylindraspis" title="Cylindraspis">Cylindraspis</a></i></li>
<li>†<i>Cymatholcus</i></li>
<li>†<i>Floridemys</i></li>
<li><i><a href="Geochelone" title="Geochelone">Geochelone</a></i></li>
<li><i><a href="Gopherus" title="Gopherus">Gopherus</a></i></li>
<li>†<i><a href="Hadrianus_(turtle)" title="Hadrianus (turtle)">Hadrianus</a></i></li>
<li>†<i><a href="Hesperotestudo" title="Hesperotestudo">Hesperotestudo</a></i></li>
<li><i><a href="Homopus" title="Homopus">Homopus</a></i></li>
<li><i><a href="Indotestudo" title="Indotestudo">Indotestudo</a></i></li>
<li><i><a href="Kinixys" title="Kinixys">Kinixys</a></i></li>
<li><i><a href="Pancake_tortoise" title="Pancake tortoise">Malacochersus</a></i></li>
<li><i><a href="Manouria" title="Manouria">Manouria</a></i></li>
<li>†<i><a href="Megalochelys" title="Megalochelys">Megalochelys</a></i></li>
<li>†<i>Oligopherus</i></li>
<li><i><a href="Psammobates" title="Psammobates">Psammobates</a></i></li>
<li><i><a href="Pyxis_(turtle)" title="Pyxis (turtle)">Pyxis</a></i></li>
<li>†<i><a href="Solitudo" title="Solitudo">Solitudo</a></i></li>
<li><i><a href="Leopard_tortoise" title="Leopard tortoise">Stigmochelys</a></i></li>
<li>†<i><a href="Stylemys" title="Stylemys">Stylemys</a></i></li>
<li><i><a href="Testudo_(genus)" title="Testudo (genus)">Testudo</a></i></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em"><a href="Trionychia" title="Trionychia">Trionychia</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Pig-nosed_turtle" title="Pig-nosed turtle">Carettochelyidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Allaeochelys" title="Allaeochelys">Allaeochelys</a></i></li>
<li>†<i><a href="Anosteira" title="Anosteira">Anosteira</a></i></li>
<li><i><a href="Pig-nosed_turtle" title="Pig-nosed turtle">Carettochelys</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Trionychidae" title="Trionychidae">Trionychidae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="Amyda" title="Amyda">Amyda</a></i></li>
<li><i><a href="Apalone" title="Apalone">Apalone</a></i></li>
<li>†<i><a href="Axestemys" title="Axestemys">Axestemys</a></i></li>
<li><i><a href="Chitra_(turtle)" title="Chitra (turtle)">Chitra</a></i></li>
<li><i><a href="Cyclanorbis" title="Cyclanorbis">Cyclanorbis</a></i></li>
<li><i><a href="Cycloderma" title="Cycloderma">Cycloderma</a></i></li>
<li>†<i><a href="Drazinderetes" title="Drazinderetes">Drazinderetes</a></i></li>
<li><i><a href="Malayan_softshell_turtle" title="Malayan softshell turtle">Dogania</a></i></li>
<li>†<i><a href="Gilmoremys" title="Gilmoremys">Gilmoremys</a></i></li>
<li>†<i><a href="Hutchemys" title="Hutchemys">Hutchemys</a></i></li>
<li>†<i><a href="Khunnuchelys" title="Khunnuchelys">Khunnuchelys</a></i></li>
<li><i><a href="Lissemys" title="Lissemys">Lissemys</a></i></li>
<li><i><a href="Nilssonia_(turtle)" title="Nilssonia (turtle)">Nilssonia</a></i></li>
<li><i><a href="Wattle-necked_softshell_turtle" title="Wattle-necked softshell turtle">Palea</a></i></li>
<li>†<i><a href="Palaeoamyda" title="Palaeoamyda">Palaeoamyda</a></i></li>
<li><i><a href="Pelochelys" title="Pelochelys">Pelochelys</a></i></li>
<li><i><a href="Pelodiscus" title="Pelodiscus">Pelodiscus</a></i></li>
<li><i><a href="Rafetus" title="Rafetus">Rafetus</a></i></li>
<li><i><a href="Trionyx" title="Trionyx">Trionyx</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"> </th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Basilochelys" title="Basilochelys">Basilochelys</a></i></li>
<li>†<i><a href="Sinaspideretes" title="Sinaspideretes">Sinaspideretes</a></i></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em"> </th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Chelydridae66" scope="row" class="navbox-group" style="width:11em"><a href="Chelydridae" title="Chelydridae">Chelydridae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="Chelydra" title="Chelydra">Chelydra</a></i></li>
<li>†<i><a href="Chelydrops" title="Chelydrops">Chelydrops</a></i></li>
<li>†<i><a href="Chelydropsis" title="Chelydropsis">Chelydropsis</a></i></li>
<li>†<i><a href="Emarginachelys" title="Emarginachelys">Emarginachelys</a></i></li>
<li>†<i><a href="Macrocephalochelys" title="Macrocephalochelys">Macrocephalochelys</a></i></li>
<li><i><a href="Macrochelys" title="Macrochelys">Macrochelys</a></i></li>
<li>†<i><a href="Planiplastron" title="Planiplastron">Planiplastron</a></i></li>
<li>†<i><a href="Protochelydra" title="Protochelydra">Protochelydra</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em">†<a href="Nanhsiungchelyidae" title="Nanhsiungchelyidae">Nanhsiungchelyidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Anomalochelys" title="Anomalochelys">Anomalochelys</a></i></li>
<li>†<i><a href="Basilemys" title="Basilemys">Basilemys</a></i></li>
<li>†<i><a href="Jiangxichelys" title="Jiangxichelys">Jiangxichelys</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em">†<a href="Protostegidae" title="Protostegidae">Protostegidae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Alienochelys" title="Alienochelys">Alienochelys</a></i></li>
<li>†<i><a href="Archelon" title="Archelon">Archelon</a></i></li>
<li>†<i><a href="Atlantochelys" title="Atlantochelys">Atlantochelys</a></i></li>
<li>†<i><a href="Bouliachelys" title="Bouliachelys">Bouliachelys</a></i></li>
<li>†<i><a href="Calcarichelys" title="Calcarichelys">Calcarichelys</a></i></li>
<li>†<i><a href="Cratochelone" title="Cratochelone">Cratochelone</a></i></li>
<li>†<i><a href="Desmatochelys" title="Desmatochelys">Desmatochelys</a></i></li>
<li>†<i><a href="Iserosaurus" title="Iserosaurus">Iserosaurus</a></i></li>
<li>†<i><a href="Notochelone" title="Notochelone">Notochelone</a></i></li>
<li>†<i><a href="Ocepechelon" title="Ocepechelon">Ocepechelon</a></i></li>
<li>†<i><a href="Pneumatoarthrus" title="Pneumatoarthrus">Pneumatoarthrus</a></i></li>
<li>†<i><a href="Protostega" title="Protostega">Protostega</a></i></li>
<li>†<i><a href="Rhinochelys" title="Rhinochelys">Rhinochelys</a></i></li>
<li>†<i><a href="Santanachelys" title="Santanachelys">Santanachelys</a></i></li>
<li>†<i><a href="Terlinguachelys" title="Terlinguachelys">Terlinguachelys</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"> </th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Adocus" title="Adocus">Adocus</a></i></li>
<li>†<i><a href="Argillochelys" title="Argillochelys">Argillochelys</a></i></li>
<li>†<i><a href="Bashuchelys" title="Bashuchelys">Bashuchelys</a></i></li>
<li>†<i><a href="Ctenochelys" title="Ctenochelys">Ctenochelys</a></i></li>
<li>†<i><a href="Prionochelys" title="Prionochelys">Prionochelys</a></i></li>
<li>†<i><a href="Toxochelys" title="Toxochelys">Toxochelys</a></i></li></ul>
</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="Pleurodira" title="Pleurodira">Pleurodira</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="6" scope="row" class="navbox-group" style="width:10em"> </th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:11em">†<a href="Araripemydidae" title="Araripemydidae">Araripemydidae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Araripemys" title="Araripemys">Araripemys</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em">†<a href="Bothremydidae" title="Bothremydidae">Bothremydidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Araiochelys" title="Araiochelys">Araiochelys</a></i></li>
<li>†<i><a href="Arenila" title="Arenila">Arenila</a></i></li>
<li>†<i><a href="Azabbaremys" title="Azabbaremys">Azabbaremys</a></i></li>
<li>†<i><a href="Bothremys" title="Bothremys">Bothremys</a></i></li>
<li>†<i><a href="Cearachelys" title="Cearachelys">Cearachelys</a></i></li>
<li>†<i><a href="Chedighaii" title="Chedighaii">Chedighaii</a></i></li>
<li>†<i><a href="Chupacabrachelys" title="Chupacabrachelys">Chupacabrachelys</a></i></li>
<li>†<i><a href="Eotaphrosphys" title="Eotaphrosphys">Eotaphrosphys</a></i></li>
<li>†<i><a href="Foxemys" title="Foxemys">Foxemys</a></i></li>
<li>†<i><a href="Galianemys" title="Galianemys">Galianemys</a></i></li>
<li>†<i><a href="Ilatardia" title="Ilatardia">Ilatardia</a></i></li>
<li>†<i><a href="Inaechelys" title="Inaechelys">Inaechelys</a></i></li>
<li>†<i><a href="Itapecuruemys" title="Itapecuruemys">Itapecuruemys</a></i></li>
<li>†<i><a href="Jainemys" title="Jainemys">Jainemys</a></i></li>
<li>†<i><a href="Kinkonychelys" title="Kinkonychelys">Kinkonychelys</a></i></li>
<li>†<i><a href="Kurmademys" title="Kurmademys">Kurmademys</a></i></li>
<li>†<i><a href="Labrostochelys" title="Labrostochelys">Labrostochelys</a></i></li>
<li>†<i><a href="Nigeremys" title="Nigeremys">Nigeremys</a></i></li>
<li>†<i><a href="Phosphatochelys" title="Phosphatochelys">Phosphatochelys</a></i></li>
<li>†<i><a href="Polysternon" title="Polysternon">Polysternon</a></i></li>
<li>†<i><a href="Puentemys" title="Puentemys">Puentemys</a></i></li>
<li>†<i><a href="Rosasia" title="Rosasia">Rosasia</a></i></li>
<li>†<i><a href="Rhothonemys" title="Rhothonemys">Rhothonemys</a></i></li>
<li>†<i><a href="Sankuchemys" title="Sankuchemys">Sankuchemys</a></i></li>
<li>†<i><a href="Taphrosphys" title="Taphrosphys">Taphrosphys</a></i></li>
<li>†<i><a href="Ummulisani" title="Ummulisani">Ummulisani</a></i></li>
<li>†<i><a href="Zolhafah" title="Zolhafah">Zolhafah</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Chelidae" title="Chelidae">Chelidae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="Acanthochelys" title="Acanthochelys">Acanthochelys</a></i></li>
<li><i><a href="Chelodina" title="Chelodina">Chelodina</a></i></li>
<li><i><a href="Mata_mata" title="Mata mata">Chelus</a></i></li>
<li><i><a href="Elseya" title="Elseya">Elseya</a></i></li>
<li><i><a href="Mary_River_turtle" title="Mary River turtle">Elusor</a></i></li>
<li><i><a href="Emydura" title="Emydura">Emydura</a></i></li>
<li><i><a href="Hydromedusa" title="Hydromedusa">Hydromedusa</a></i></li>
<li>†<i><a href="Lomalatachelys" title="Lomalatachelys">Lomalatachelys</a></i></li>
<li><i><a href="Mesoclemmys" title="Mesoclemmys">Mesoclemmys</a></i></li>
<li><i><a href="Myuchelys" title="Myuchelys">Myuchelys</a></i></li>
<li><i><a href="Phrynops" title="Phrynops">Phrynops</a></i></li>
<li><i><a href="Twist-necked_turtle" title="Twist-necked turtle">Platemys</a></i></li>
<li>†<i><a href="Prochelidella" title="Prochelidella">Prochelidella</a></i></li>
<li><i><a href="Western_swamp_turtle" title="Western swamp turtle">Pseudemydura</a></i></li>
<li><i><a href="Rheodytes" title="Rheodytes">Rheodytes</a></i></li>
<li><i><a href="Red_side-necked_turtle" title="Red side-necked turtle">Rhinemys</a></i></li>
<li>†<i><a href="Yaminuechelys" title="Yaminuechelys">Yaminuechelys</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Pelomedusidae" title="Pelomedusidae">Pelomedusidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li><i><a href="African_helmeted_turtle" title="African helmeted turtle">Pelomedusa</a></i></li>
<li><i><a href="Pelusios" title="Pelusios">Pelusios</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em"><a href="Podocnemididae" title="Podocnemididae">Podocnemididae</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Albertwoodemys" title="Albertwoodemys">Albertwoodemys</a></i></li>
<li>†<i><a href="Bauruemys" title="Bauruemys">Bauruemys</a></i></li>
<li>†<i><a href="Brontochelys" title="Brontochelys">Brontochelys</a></i></li>
<li>†<i><a href="Caninemys" title="Caninemys">Caninemys</a></i></li>
<li>†<i><a href="Carbonemys" title="Carbonemys">Carbonemys</a></i></li>
<li>†<i><a href="Cerrejonemys" title="Cerrejonemys">Cerrejonemys</a></i></li>
<li>†<i><a href="Cordichelys" title="Cordichelys">Cordichelys</a></i></li>
<li><i><a href="Madagascan_big-headed_turtle" title="Madagascan big-headed turtle">Erymnochelys</a></i></li>
<li>†<i><a href="Lapparentemys" title="Lapparentemys">Lapparentemys</a></i></li>
<li>†<i><a href="Latentemys" title="Latentemys">Latentemys</a></i></li>
<li><i><a href="Big-headed_Amazon_River_turtle" title="Big-headed Amazon River turtle">Peltocephalus</a></i></li>
<li><i><a href="Podocnemis" title="Podocnemis">Podocnemis</a></i></li>
<li>†<i><a href="Stupendemys" title="Stupendemys">Stupendemys</a></i></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:11em">†<a href="Sahonachelyidae" title="Sahonachelyidae">Sahonachelyidae</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Sahonachelys" title="Sahonachelys">Sahonachelys </a></i></li>
<li>†<i><a href="Sokatra" title="Sokatra">Sokatra</a></i></li></ul>
</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"> </th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="6" scope="row" class="navbox-group" style="width:10em"> </th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:11em"> </th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em">
<ul><li>†<i><a href="Caribemys" class="mw-redirect" title="Caribemys">Caribemys</a></i></li>
<li>†<i><a href="Caririemys" title="Caririemys">Caririemys</a></i></li>
<li>†<i><a href="Tacuarembemys" title="Tacuarembemys">Tacuarembemys</a></i></li></ul>
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<ul><li>Phylogenetic arrangement of turtles based on <a rel="nofollow" class="external text" href="http://images.turtleconservancy.org/documents/2017/crm-7-checklist-atlas-v8-2017.pdf"><i>Turtles of the World 2017 Update: Annotated Checklist and Atlas of Taxonomy, Synonymy, Distribution, and Conservation Status</i></a>. † = extinct.</li></ul>
<ul><li>See also <a href="List_of_Testudines_families" title="List of Testudines families">List of Testudines families</a></li></ul>
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