5 research outputs found
Bourque Appendix 2 Revision2
character/taxon matrix used in phylogenetic analysis (in Excel format
Fossil musk turtles (Kinosternidae, <i>Sternotherus</i>) from the late Miocene–early Pliocene (Hemphillian) of Tennessee and Florida
<div><p>ABSTRACT</p><p>The oldest fossil musk turtles, genus <i>Sternotherus</i>, are reported from the Hemphillian of eastern Tennessee and central Florida. <i>Sternotherus palaeodorus</i>, n. sp., is known from five partial shells discovered at the late Miocene–early Pliocene (7–4.5 Ma; late Hemphillian) Gray Fossil Site in Washington County, Tennessee. <i>Sternotherus palaeodorus</i> possesses an enlarged intergular scute, wide first vertebral scute that overlaps peripheral set 1, posteriorly extensive hypoplastron to peripheral 7 contact, and a posteriorly situated inguinal musk duct pore (characteristics more typically seen in <i>Kinosternon</i>). A cladistic analysis recovered <i>S. palaeodorus</i> within crown group <i>Sternotherus</i> in the strict consensus and on the stem of <i>Sternotherus</i> in the majority rule consensus. <i>Sternotherus bonevalleyensis</i>, n. sp., from the Palmetto Fauna (5.5–5 Ma; late Hemphillian) of central Florida was perhaps contemporaneous with <i>S. palaeodorus</i> and is known only from isolated shell fragments. It is morphologically most similar to the <i>Sternotherus minor</i> complex and <i>Sternotherus depressus</i>. Subsequent Blancan fossils from the Suwannee River of Florida represent aff. <i>S. minor peltifer</i>. Additionally, a fragmentary left hyoplastron of cf. <i>Sternotherus</i> from Haile 19A, Alachua County, Florida, could be the oldest record for the genus (ca. 9–8.5 Ma; early Hemphillian). These accounts reveal that <i>Sternotherus</i> was diverse and moderately well distributed geographically by its first known fossil occurrences and support previous hypotheses that the <i>Sternotherus minor</i> complex evolved in the Gulf coastal plain and dispersed throughout that region since at least the latest Miocene–earliest Pliocene. </p><p>http://zoobank.org/urn:lsid:zoobank.org:pub:A1B8586C-0FCB-4B5E-B0B3-BD2D55B1ADC8</p><p>SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP </p></div
A new dermatemydid (Testudines, Kinosternoidea) from the Paleocene-Eocene Thermal Maximum, Willwood Formation, southeastern Bighorn Basin, Wyoming
<div><p>ABSTRACT</p><p><i>Gomphochelys nanus</i>, new genus and species, is described from the earliest Wasatchian (biohorizon Wa 0; ∼55.8 Ma) of the southeastern Bighorn Basin, Washakie County, Wyoming. The new taxon represents the only known dermatemydid from the Paleocene–Eocene Thermal Maximum (PETM) interval and extends the lineage back from previous records by approximately 2 million years. <i>Gomphochelys nanus</i> has a thick tricarinate carapace and differs from other dermatemydids in attaining a smaller adult body size, having reduced plastral features, a posteriorly situated gular–humeral sulcus, an acarinate pygal, and thick shortened peripherals. Reexamination of previously described fossil dermatemydids suggests that the taxa <i>Baptemys tricarinata</i> and <i>Kallistira costilata</i> are junior synonyms of the middle–late Wasatchian <i>Notomorpha garmanii</i>, and <i>Baptemys fluviatilis</i> is likely a junior synonym of <i>Baptemys wyomingensis</i>. <i>Gomphochelys nanus</i> is a stem dermatemydid that is similar to <i>N. garmanii</i> but differs in possessing symplesiomorphies with the Late Cretaceous–Paleocene genera <i>Agomphus</i> and <i>Hoplochelys</i>. Aspects of shell morphology suggest that <i>G. nanus</i> was a commensurate swimmer and bottom-walker like extant <i>Dermatemys</i> and <i>Staurotypus</i>. The presence of a dermatemydid (a tropically distributed clade) in the southeastern Bighorn Basin during the PETM (when global temperatures increased by 5°C–10°C over a period of ∼60 ky) further supports the hypothesis that climate was megathermal in the region during this interval and is consistent with previously documented geographic range changes in both plants and animals. Dermatemydids disappear from the fossil record at the end of the PETM and don't reemerge until the next warming event, Eocene Thermal Maximum 2.</p><p>http://zoobank.org/urn:lsid:zoobank.org:pub:19A98079-5CAD-4BC5-8C21-2810AA576D98 </p><p>SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP</p></div