Fossil Turtles Research Articles

Fossil turtle eggs from the Upper Cretaceous Gaogou Formation, Xiaguan-Gaoqiu Basin, Neixiang County, Henan Province, China: Interpretation of the transformation from aragonite to calcite in fossil turtle eggshell

In 2007, a clutch of approximately 30 fossil eggs reported from the Upper Cretaceous Gaogou Formation, Xiaguan-Gaoqiu Basin, Neixiang County, Henan Province, China was assigned to the oofamily “Crocodiloolithidae”. After 11 years, another clutch of 15 eggs of the same type associated with Mosaiceratops azumai and from the same county was identified as turtle eggs (Testudoolithus), based on the needle-like crystals interpreted as aragonite from their eggshells. Our detailed study of the clutch of 15 eggs and six clutches of the same ootaxon using transmitted/polarized light microscope, followed by scanning electron microscope observations combined with electron backscatter diffraction analysis showed that their eggshells are dominated by secondary calcite; with a few pristine aragonite crystals that unequivocally support the turtle affinity of the eggs. Furthermore, superimposed cone-shaped structural units with radial ultrastructures, combined with the extremely thick eggshell challenges the assignment to the oogenus Testudoolithus. Hence, we suggest that this ootaxon could represent a new oogenus of Testudoolithidae. Although additional eggshell units were reported in the abnormal fossil turtle egg with multilayered eggshell from the Judith River Formation in Montana, U.S.A, the relatively constant eggshell thickness indicates that the eggs from Neixiang are not pathological. Therefore, this is the first report of superimposed structural units inside normal turtle eggshells, revealing the unique eggshell formation mechanism of the extinct turtle from Neixiang. Moreover, the aragonite discovered in the eggs may extend the temporal record of confirmed aragonite in turtle eggs. The crystallographic comparison between the eggs from Neixiang and the fossil turtle eggshells from Zhejiang Province and Montana revealed the transformation process from aragonite to calcite in fossil turtle eggshell.

Preservation of aragonite in Late Cretaceous (Campanian) turtle eggshell

Among amniotes, turtles are the only clade that lay aragonitic eggs. Because aragonite is a metastable mineral, unequivocal preservation of aragonite in fossil turtle eggs has only been reported from Pliocene deposits. Here, we report in situ preservation of aragonite in a turtle egg from the Judith River Formation (Campanian) of Montana, USA. We utilized electron backscatter diffraction (EBSD) and Raman spectroscopy to explore the carbonate mineral polymorphs in the eggshell. The EBSD maps show the presence of both aragonite and calcite with the former preserved as needle-like crystal, a feature of all turtle eggshells. The presence of aragonite is independently validated by Raman maps. This dual approach provides direct, unambiguous evidence that the record of aragonitic turtle eggshell dates back at least to the Campanian (ca. 76 Ma) and supports the hypothesis that aragonitic eggshell is a synapomorphy of all turtles. The presence of pristine aragonite also indicates minimal taphonomic alteration at the fossil locality. Consequently, diverse invertebrate or vertebrate fossils from localities with aragonitic turtle eggs may provide high quality, unaltered palaeoenvironmental information. • A Late Cretaceous turtle egg preserves aragonite. • EBSD and Raman spectroscopy provide independent approach. • It supports the view that aragonitic egg is synapomorphic to all Testudinata. • Judith River Formation and its equivalent strata may preserve more aragonitic fossils.

Turtles all the way down: Neogene pig‐nosed turtle fossil from southern Australia reveals cryptic freshwater turtle invasions and extinctions

AbstractThe extant pig‐nosed turtle (Carettochelys insculpta), persisting in far northern Australia and southern New Guinea, is the last surviving member of Carettochelyidae and the only non‐Gondwanan freshwater turtle lineage in Australia. Despite having a global fossil record dating to the Cretaceous, the absence of carettochelyid fossils from Australia has implied a relatively recent colonization of this landmass. Here we report an upper Miocene to lower Pliocene carettochelyid fossil from Beaumaris, Victoria, in south‐eastern Australia. This record is the most southerly occurrence of the clade Carettochelyidae. The presence of carettochelyids in southern Australia, and a discontinuous record of trionychids (soft‐shell turtles) in the Cenozoic of Queensland, suggests at least two colonizations of Australia by Trionychia, pre‐dating the extant pig‐nosed turtle. This cryptic southern history of tropical soft‐shell and pig‐nosed turtles ended before the recent aridification of Australia, leaving the Gondwanan side‐necked turtles as the dominant turtle group in Australian freshwater ecosystems. Therefore, this singular fossil reveals a previously unknown shift in the diversity and evolutionary history of freshwater turtles in Australia.

A new model of forelimb ecomorphology for predicting the ancient habitats of fossil turtles.

Various morphological proxies have been used to infer habitat preferences among fossil turtles and their early ancestors, but most are tightly linked to phylogeny, thereby minimizing their predictive power. One particularly widely used model incorporates linear measurements of the forelimb (humerus + ulna + manus), but in addition to the issue of phylogenetic correlation, it does not estimate the likelihood of habitat assignment. Here, we introduce a new model that uses intramanual measurements (digit III metacarpal + non‐ungual phalanges + ungual) to statistically estimate habitat likelihood and that has greater predictive strength than prior estimators. Application of the model supports the hypothesis that stem‐turtles were primarily terrestrial in nature and recovers the nanhsiungchelyid Basilemys (a fossil crown‐group turtle) as having lived primarily on land, despite some prior claims to the contrary.

Fossil turtles from the early Miocene localities of Mokrá-Quarry (Burdigalian, MN4), South Moravian Region, Czech Republic

Fossil turtles from Mokrá-Quarry, South Moravia Region, Czech Republic, are described in this paper. Remains come from two already known karstic fissures uncovered in Mokrá-Western Quarry (1/2001 Turtle Joint and 2/2003 Reptile Joint), as well as three new karstic fissures from Mokrá-Western Quarry (TC/2001 and 4/2018) and Mokrá-Central Quarry (3/2005). All localities correspond to the early Miocene (Burdigalian: late Eggenburgian-Ottnangian MN4). The newly described material belongs to several turtle individuals, including over 100 shell elements, so the material studied here constitutes one of the largest samples in regards of the Czech Republic fossil record. Most of these remains have been identified as Ptychogaster (Ptychogaster) sp. and Testudo (Chersine) cf. kalksburgensis Toula, 1896. However, three specimens presented here (i.e., one shell fragment and two postcranial bones) have been identified as a large tortoise (Testudinidae indet.). Turtle fauna is congruent with two ecological environments, including a dry karst landscape with open to dense steppe vegetation inferred for the heliophile testudinids, as well as freshwater masses to the semi-terrestrial ptychogasterid. Finally, this paper expands our knowledge of fossil turtle assemblages in Central Europe during the early Miocene.

Ectoparasite borings, mesoparasite borings, and scavenging traces in early Miocene turtle and tortoise shell: Moghra Formation, Wadi Moghra, Egypt

AbstractBorings and bite marks on fossil turtle carapaces and plastra from the Miocene Moghra Formation, northern Egypt, are herein described. All fossil turtle material from Moghra exhibits ichnofossils. The positions of invertebrate borings on external surfaces of tortoise and turtle shell material at Moghra are consistent with the activities of ectoparasites or mesoparasites.A single invertebrate ichnotaxon, Karethraichnus lakkos Zonneveld et al., 2016, occurs on Moghra tortoise fossils. This trace fossil was likely emplaced by ixodid arthropods (ticks). Bite marks assigned to Nihilichnus occur on a carapace peripheral and are interpreted to reflect postmortem scavenging. An abundant and moderately diverse assemblage of invertebrate borings characterizes Moghra aquatic turtle shells. Karethraichnus lakkos and Thatchtelithichnus holmani Zonneveld et al., 2016 traces on aquatic turtles are interpreted to reflect leech and/or trematode parasitism. Gunnellichnus moghraensis (new ichnogenus new ichnospecies) and G. akolouthiste (n. isp.) likely reflect bacterial and/or fungal infections on aquatic turtle shells that rarely dried out.UUID: http://zoobank.org/f0a3977d-deff-4954-b196-536adc405854

The Scontrone turtles – A new insular testudinoid fauna from the late Miocene of the Central Mediterranean

We here describe a small turtle assemblage originating from the early Tortonian (late Miocene) palaeoisland of Scontrone, central Italy, a locality previously known mostly for its endemic mammals and giant birds, which were otherwise shared only with the Gargano localities, another fossiliferous area belonging to the same palaeobioprovince. The fossil turtle remains from Scontrone are referred to the geoemydid Mauremys sp. and a so far unidentified large-sized testudinid. The biogeographic origins of the Scontrone insular chelonians are discussed. The Scontrone geoemydid adds to the known occurrences of Mauremys in the late Miocene of the Mediterranean. The Scontrone large tortoise represents the oldest known Mediterranean insular testudinid, predating significantly the well-known Quaternary endemic island tortoises of the area.

Turtle and pterosaur tracks from the Los Cayos Dinosaur Tracksite, Cameros Basin (Cornago, La Rioja, Spain): tracking the Lower Cretaceous bio-diversity

New fossil turtle and pterosaurian tracks have been found at the Los Cayos locality (Cornago township, La Rioja province, Spain). The Los Cayos tracksite is situated in the Cameros Basin, ant it is included in the Enciso Group, which is late Barremian-Early Aptian in age (Lower Cretaceous). The turtle tracks are formed by parallel isolated digit impressions. Digits show acuminate distal ends and relatively blunt proximal margins. Most of the tracks show three digits, and only two of them are pentadactyl. No trackways can be observed but only different track alignments suggesting some kind of direction of movement. Two track-bearing layers have yielded 5 pterosaur manus prints. No pes footprints or trackways have been discovered at these outcrops yet. These prints are tridactyl, with digit I, the shortest, and III, the longest. The angles between the digits are variable: angle I-II is significantly bigger than between II-III. These tracks from Los Cayos were the first discovery of pterosaur tracks in the Enciso Group.

The freshwater and terrestrial turtles from Monte Pila and Fuenmayor (La Rioja, northern Spain): new data on the lower Miocene turtle diversity of the Ebro Basin

Abundant turtle fossils from two lower Miocene localities in which this lineage had not previously been studied are described herein. The localities are Monte Pila and Fuenmayor, which are 10 km apart, both located in the Autonomous Community of La Rioja (northern Spain), in the Ebro Basin. Information about the turtles from the lower Miocene levels in this basin was until now restricted to the finds made in the MN3 biozone of the Bardenas Reales of Navarre. Several turtle taxa had been recognized there. However, the material attributed to each of them was scarce. Monte Pila and Fuenmayor are located in biozone MN2. The remains of turtles are abundant in both sites. A terrestrial lineage, recognized at Monte Pila, is not represented in the Bardenas Reales fauna of Navarre. It represents the first record of TitanochelonPérez-García & Vlachos, 2014 in La Rioja and is one of the oldest member of this genus, being assigned to Titanochelon cf. bolivari (Hernández-Pacheco, 1917). The only lineage of turtles identified in Fuenmayor, and the most abundant in Monte Pila, is Ptychogasterinae. All material of this clade of freshwater turtles identified there is compatible with a single form, for which a high range of intraspecific variability is recognized. It is attributed to Ptychogaster (Temnoclemmys) cf. bardenensis Murelaga, Lapparent de Broin, Pereda Suberbiola & Astibia, 1999, this species having been recognized, until now, as exclusive to the Bardenas Reales of Navarre.

Les tortues du Mésozoïque du Havre (France), révisions, définition de Globochelus lennieri n. g. n. sp. et nouvelles données sur Tropidemys langii, Plesiochelyidae

The collection of Mesozoïc turtles conserved in the Museum of Le Havre is revised, being enhanced after the destruction which occurred during the World War II. The new purchases, including two new Jurassic (Lower Kimmeridgian) taxa of the family Plesiochelyidae, from the Cap de la Hève and Bléville respectively, are compared to the previously described turtle and now destroyed remains of the Le Havre area. On the one hand, Globochelus lennieri n. g., n. sp., from the basal Kimmeridgian Baylei biozone is the oldest plesiochelyid species named from the Upper Jurassic, that we dedicate to Lennier, in tribute to his works about geology and fossils from Le Havre. On the other hand, Tropidemys langii, from the Cymodoce biozone, is a form from the European Kimmeridgian whose presence in the Normandy region was doubted. The stratigraphic series of Le Havre, from Lennier and recent works, the sedimentology of the fossiliferous layers and the petrography of the calcareous matrix are examined, showing a littoral platform environment. The Le Havre fossil turtle record including destroyed species is reconsidered: notably the Lower Kimmeridgian plesiochelyid Plesiochelys dollfusii (Lennier), this species being clearly distinctive in the genus, and the early Cretaceous « Palaeochelys » novemcostatus Valenciennes, attibuted to a pre-employed genus but which is here confirmed as a Chelonioidea as, perhaps, “Pelobatochelys sp?”. The morphology of the shell of each plesiochelyid genus is compared. Some species previously attributed to Thalassemys are integrated in plesiochelyid genera.

The ecomorphology of the shell of extant turtles and its applications for fossil turtles.

Turtles are a successful clade of reptiles that originated in the Late Triassic. The group adapted during its evolution to different types of environments, ranging from dry land to ponds, rivers, and the open ocean, and survived all Mesozoic and Cenozoic extinction events. The body of turtles is characterized by a shell, which has been hypothesized to have several biological roles, like protection, thermal and pH regulation, but also to be adapted in its shape to the ecology of the animal. However, only few studies have investigated the relationships between shell shape and ecology in a global context or clarified if shape can be used to diagnose habitat preferences in fossil representatives. Here, we assembled a three-dimensional dataset of 69 extant turtles and three fossils, in particular, the Late Triassic Proganochelys quenstedtii and Proterochersis robusta and the Late Jurassic Plesiochelys bigleri to test explicitly for a relationship between shell shape and ecology. 3D models were obtained using surface scanning and photogrammetry. The general shape of the shells was captured using geometric morphometrics. The habitat ecology of extant turtles was classified using the webbing of their forelimbs as a proxy. Principal component analysis (PCA) highlights much overlap between habitat groups. Discriminant analyses suggests significant differences between extant terrestrial turtles, extant fully aquatic (i.e., marine and riverine) turtles, and an unspecialized assemblage that includes extant turtles from all habitats, mostly freshwater aquatic forms. The paleoecology of the three fossil species cannot be determined with confidence, as all three fall within the unspecialized category, even if Plesiochelys bigleri plots closer to fully aquatic turtles, while the two Triassic species group closer to extant terrestrial forms. Although the shape of the shell of turtles indeed contains an ecological signal, it is overall too weak to uncover using shell shape in paleoecological studies, at least with the methods we selected.

The fossil record of turtles and tortoises (Testudines) of Mexico, Central America and the Caribbean Islands, with comments on its taxonomy and paleobiogeography: a bibliographic review

Testudines is the crown-group that includes all living forms of turtles and their closest relatives. This group is known from the late Triassic and persists to this day. The fossil record of Testudines in Mexico is scarce and has been previously compiled in several papers. Here we present an update including all osteological and ichnological records from México and Central America. In Mexico, the Testudines fossil record extends from the Late Triassic to the Pleistocene, being widely abundant during the Pleistocene. Kinosternon and Gopherus are the best represented taxa, known from the late Miocene (Hemphillian) to the late Pleistocene (Rancholabrean). Fossil turtles are well represented in Mexico, excluding the states of Campeche, Mexico City, Colima, Guerrero, Queretaro, Quintana Roo and Sinaloa. On the contrary, the ichnological records are only known in Coahuila, Puebla and Zacatecas. In Central America there are records of fossil turtles in El Salvador, Honduras, Costa Rica and Panama, the latter being the country holding most records. Finally, nine new species have been described in the region, six for Mexico (Notoemys tlaxiacoensis, Yelmochelys rosarioae, Mexichelys coahuilaensis, Gopherus donlaloi, G. auffenbergi and G. pargensis, of which G. auffenbergi is synonymous with G. berlandieri and G. pargensis is considered a nomen vanum) and three in Central America (Rhinoclemmys nicoyama from Costa Rica, and Rhinoclemmys panamaensis and Staurotypus moschus from Panama).

A new bothremydid turtle (Pleurodira) from the Upper Cretaceous (Cenomanian) of Madagascar

The find of a partial shell of a pleurodiran turtle from the Cenomanian (basal Upper Cretaceous) of Madagascar was reported in the 1980s. It was then referred to as a potential member of the bothremydid Bothremys, but it has remained unpublished until now. Its attribution to Bothremydidae is confirmed here, since it is identified as a representative of Bothremydina, a clade known by several freshwater to littoral species from North America, southwestern Europe, northern Africa and the Middle East. The turtle from Madagascar, showing several exclusive characters within this lineage, is attributed to a new littoral form, Akoranemys madagasika gen. et sp. nov. It corresponds to one of the few Mesozoic turtle taxa defined in Madagascar, where only two pleurodires, belonging to other clades (the bothremydid Kurmademydini and the non-bothremydid Euraxemydidae), had been recognized at a specific level, both species being exclusive to the Maastrichtian record of that country. Therefore, Akoranemys madagasika corresponds to the oldest turtle defined for the fossil record of Madagascar, but also to one of the oldest known members of Bothremydina worldwide. The analyzed specimen is the only Mesozoic fossil turtle so far identified in the southwestern area of Madagascar, all other remains from that country coming from the northwestern region. Therefore, the presence of Bothremydina in Madagascar is confirmed by this unique member defined for the Southern Hemisphere, and the palaeobiogeographic distribution of this lineage is remarkably expanded.

Geochemical characterization of fossil turtles from Tartaruguito outcrop (Upper Cretaceous, Bauru Basin, Presidente Prudente Formation), São Paulo state, southeastern Brazil

The Tartaruguito outcrop (Pirapozinho municipality, Presidente Prudente Formation, Bauru Basin) has been considered a Fossil-Lagerstätte due to its exceptional fossil quality and large number of fossils recovered. Despite its historical and paleontological importance, a geochemical composition study of the fossils from this site and their sedimentary matrixes has never been performed. Here, we have analyzed fossil turtle shell fragments and their respective sedimentary matrixes collected at Tartaruguito through Powder X-Ray Diffraction and Infrared Spectroscopy techniques, to determine their geochemical composition and obtain clues regarding the fossil diagenesis processes. The analyses showed that the fossil remains of the side-necked turtle Bauruemys elegans from the Tartaruguito locality are mainly composed of calcite (CaCO3) and hydroxyapatite partially substituted by fluorine (Ca10(PO4)6(OH)2-xFx). The sedimentary matrixes are mostly composed of quartz (SiO2) and calcite, with secondary amounts of feldspar. The presence of calcite on both, fossil and rocky matrix, might indicate that the fossil diagenesis process that occurred at the Tartaruguito locality was permineralization by calcite, especially considering the absence of quartz on the bones of the fossil specimens. Furthermore, the presence of a fluor-hydroxyapatite solid-solution might be a plausible explanation for the quality of fossils recovered in Tartaruguito, due to the better stability of fluorapatite when compared to hydroxyapatite.

In situ SEM/EDS compositional characterization of osteocytes and blood vessels in fossil and extant turtles on untreated bone surfaces; different preservational pathways microns away.

Osteocytes and blood vessels are the main cellular and tissue components of the bone tissue of vertebrates. Evidence of these soft-tissue microstructures has been widely documented in the fossil record of Mesozoic and Cenozoic turtles. However, all these studies have characterized morphologically and elementally these microstructures via isolation from the fossilized bone matrix where they were preserved or in ground sections, which could raise skepticism about the results due to potential cross-contamination or reagents effects. Fossil turtle bones from three different localities with distinct preservation environments and geological settings, including Mongolemys elegans from the Late Cretaceous of Mongolia, Allaeochelys crassesculpta from the Eocene of Germany, and a podocnemidid indet. from the Miocene of Colombia are studied here. Bone from two extant turtle species, Lepidochelys olivacea, and Podocnemis lewyana, as well as a commercial chicken Gallus gallus were used for comparisons. Scanning Electron Microscopy-Energy Dispersive Spectroscopy analyses performed directly on untreated fresh surfaces show that osteocytes-like in the fossil turtle bone are mostly composed of iron and manganese. In contrast, the in situ blood vessels-like of the fossil turtles, as well as those from the extant taxa are rich in elements typically organic in origin (carbon and nitrogen), which are absent to minimally present in the surrounding bone or rock matrix; this suggests a possible endogenous composition for these fossil structures. Also, the results presented here show that although originally both (osteocytes and blood vessels) are organic soft components of bone as evidenced in the extant turtles and chicken, they can experience completely different preservational pathways only microns away from each other in the same fossil bone.

A revision of the pelomedusoid turtle Jainemys pisdurensis from the Late Cretaceous (Maastrichtian) Lameta Formation of India.

BackgroundJainemys pisdurensis comb. nov. is an extinct pleurodiran turtle from the Late Cretaceous (Maastrichtian) of India, previously referred to Carteremys and Shweboemys. The holotype, an eroded skull, had been collected near the village of Pisdura, south of Nagpur, in Maharashtra State, while all referred shell material originates from coeval sediments exposed at the nearby village of Dongargaon. Initial estimates believed this turtle to either be an early representative of Podocnemididae or a basal representative of Pelomedusoides.MethodsWe here figure and describe all specimens that had previously been referred to Jainemys pisdurensis comb. nov. We furthermore re-evaluate the validity of this fossil turtle and explore its phylogenetic relationships within Pleurodira.ResultsThe holotype of Jainemys pisdurensis comb. nov. displays a morphology that differs substantially from that originally reported. Most notably, the palatines only have a minor contribution to the broad triturating surfaces but have a broad midline contact with each other, the pterygoids only have a midline contact of intermediate length and do not contact the opisthotics posteriorly, the basisphenoid is broad and short, and the opisthotics do not contribute to the flooring of the cavum acustico-jugulare. The referred shell material also displays a morphology different from that reported originally, in particular in that vertebral I does not contribute to the anterior margin of the carapace while the nuchal does. Phylogenetic analysis places the cranial material within the bothremydid clade Kurmademydini, while the shell material is placed in an unresolved polytomy at the base of this clade. Jainemys pisdurensis is confirmed to be a valid species of pleurodiran turtle, but the high diversity of coeval kurmademydines in India demands removal of the postcranial remains from this taxon. The realization that all valid species of Late Cretaceous (Maastrichtian) turtles from India form a clade supports the hypothesis that India was physically separated from the rest of Gondwana at this time.

New material of named fossil turtles from the Late Jurassic (late Kimmeridgian) of Wattendorf, Germany.

The newly discovered plattenkalk (platy limestone) locality of Wattendorf, southern Germany, has yielded a diverse fauna and flora dated to the base of the late Kimmeridgian, Late Jurassic. We here describe three fossil turtle specimens that were recovered during systematic excavations of a distinct, 15 cm thick package of plattenkalks by the Naturkunde-Museum Bamberg. The first specimen is a large shell of Achelonia formosa, a taxon that is based on material from the late Kimmeridgian of Cerin, France. The new specimen suggests synonymy with Enaliochelys chelonia from the late Kimmeridgian of the United Kingdom. The second is a near-complete skeleton of the enigmatic Tropidemys seebachi, which was previously known only from the late Kimmeridgian of Hannover, northern Germany. The third specimen is a partial skeleton of Eurysternum wagleri, which had previously been known only from the early Tithonian of the Solnhofen region, southern Germany. In addition to new anatomical insights, the new material provides further evidence for spatial links during the late Kimmeridgian between northern and southern Germany, France, and the United Kingdom and temporal link from the late Kimmeridgian to the early Tithonian. The prevalence of partial, though articulated specimens is suggestive of predation by an unknown large marine reptile.

Cretaceous flora and fauna of the Sustut Group near the Sustut River, northern British Columbia, Canada

A partial ornithischian dinosaur skeleton discovered near the Sustut River in 1971 has, to date, represented the only vertebrate fossil remains recovered from the Sustut Basin in northern British Columbia, Canada, but the geological provenance and age of this specimen has remained unclear. We provide new data on the age of this dinosaur specimen based on reconnaissance palaeontological prospecting along the Sustut River, and also report new vertebrate and plant fossils from this region. A skeletal fragment of a species of the turtle Basilemys Hay, 1902 was discovered at a site closely matching field notes describing the initial collection of the ornithischian dinosaur, suggesting that the new turtle fossil derives from the same locality as the dinosaur. Palynomorphs collected from this site include the marker taxon Pseudoaquilapollenites bertillonites (Sriv.), found in the lower Hell Creek Formation, and suggesting an age range of between 68.2 and 67.2 Ma for the locality. To the west of this locality we discovered multiple new fossil plant sites preserving wood and the leaves of Metasequoia Miki and several angiosperms, and one site preserved fronds resembling a species of the tree fern Coniopteris Brong., suggesting a Cenomanian or older age for sites in the area. The complex translational history of the Intermontane Terrane means that the newly discovered turtle may not represent a northern range extension for Basilemys, but it does represent one of the westernmost occurrences of this genus. The discovery of new vertebrate fossil remains in a region with relatively little accessible outcrop at present indicates the potential for future discoveries in the higher elevation outcrops of the Sustut Basin in this mountainous region of British Columbia.

A reevaluation of the basal turtle Indochelys spatulata from the Early-Middle Jurassic (Toarcian-Aalenian) of India, with descriptions of new material.

BackgroundIndochelys spatulata is an extinct turtle from the Early to Middle Jurassic Kota Formation of the Pranhita–Godavari Gondwana basin, India. The holotype and previously only known specimen is a partially eroded shell that had been collected near Kota village, north of Sironcha, in Maharashtra State. Phylogenetic analyses have consistently suggested placement at the base of the clade Mesochelydia.MethodsWe here figure and describe the holotype of Indochelys spatulata and two new specimens, which were collected from the Kota Formation near Kistapur village, Telengana State, about 60 km NW from the type locality. We furthermore explore the relationships of this fossil turtle by updating its scoring based on all available material in the most recent analysis of basal turtle relationships.ResultsThe revision of the holotype of Indochelys spatulata provides minor adjustments to the morphology of this specimen, in particular recognition of a transverse break across the carapace, presence of only eight neurals, of which the eight is octagonal, and presence of a pathological element located between neurals VII and VIII. The new material provides new anatomical insights, in particular presence of a broad cervical, a vertebral V that inserts deeply into vertebral IV, narrow pleurals within increasingly short posteromedial contacts with the vertebrals towards the posterior, at least three pairs of musk duct foramina, and numerous insights into the morphology of the girdles and stylopodium. In combination, all material allows affirming the validity of Indochelys spatulata with confidence. The phylogenetic analysis affirms the placement of Indochelys spatulata as a basal mesochelydian, but cannot resolve its relationships relative to the roughly coeval Condorchelys antiqua and Kayentachelys aprix.

Epiplastral and geographic variation in <em>Echmatemys</em>, a geoemydid turtle from the Eocene of North America: A multi-tiered analysis of epiplastral shape complexity

Author(s): Smith, Heather F.; Jager, Daniel; Hutchison, J. Howard; Adrian, Brent; Townsend, K.E. Beth | Abstract: Numerous geoemydid turtle fossils from the extinct genus Echmatemys have been recovered from the middle Eocene Uinta Formation, Uinta Basin, Utah over the past several decades. Here, we tested whether co-occurring Uintan species Echmatemys callopyge and E. uintensis can be reliably differentiated based on epiplastral morphology, and whether their geospatial distributions overlapped significantly. The geographic spatial and stratigraphic distributions of Uinta Basin E. callopyge and E. uintensis specimens were compared using ArcGIS and analysis of variance (ANOVA). The analysis revealed overlapping geographic distributions of these two species, and no significant differences in stratigraphic dispersal. This finding of extensive geospatial overlap between the two Uintan Echmatemys species highlights the need for accurate taxonomic identification, such as the gular scale morphology validated here. In addition, we sought to address a methodological question regarding the relative efficacy of data complexity in this context. Using epiplastra from three additional Eocene species of Echmatemys, we employed hierarchical analyses of increasing data complexity, from standard linear dimensions to 2D geometric morphometrics to 3D laser scans, to determine the degree to which data complexity contributes to taxonomic assessments within this genus. Uintan species E. callopyge and E. uintensis were found to differ significantly in epiplastral shape as captured by all three categories of data. These findings verify that these two co-occurring species can be differentiated consistently using the shape of the gular scale, and that the use of geometric morphometrics can improve identification of fragmentary specimens. Among the non-Uintan species, dorsal and ventral 2D landmark data reliably differentiated among species, but the linear dimensions were less useful.