[Paleontology • 2024] Xianyuechelys yingliangi • A New nanhsiungchelyid Turtle (Cryptodira: Nanhsiungchelyidae) from the Late Cretaceous of Ganzhou Basin, China

 

Xianyuechelys yingliangi 

Ke, Niu, Rummy, Tong, Hu & Han, 2024

 

DOI: 10.1080/14772019.2024.2346838

  Researchgate.net/publication/381306467

Abstract

Nanhsiungchelyidae is a group of large Pan-Trionychia that lived in North America and Asia during the Cretaceous. Despite a long research history, their taxonomy and internal nodes are still controversial. Here, we erect a new taxon, Xianyuechelys yingliangi gen. et sp. nov., from the Upper Cretaceous Lianhe Formation of Ganzhou Basin, China. Xianyuechelys yingliangi is attributed to Nanhsiungchelyidae based on its carapace being covered by a sculpturing of large pits. However, the new species also possesses an unique combination of characteristics among nanhsiungchelyids such as a wide, crescentic nuchal, absence of a pair of anterolateral processes, and the fourth and fifth vertebral scutes that contact at a point. The holotype is a juvenile or sub-adult based on the incomplete ossification of carapace, but its morphological characteristics can mostly be regarded as taxonomically informative rather than ontogenetic in origin. Phylogenetic analysis suggests Xianyuechelys yingliangi forms a monophyletic group with Nanhsiungchelys spp. and Anomalochelys angulata, supported by two unambiguous synapomorphies: wide vertebral scutes and wide neurals. The phylogenetic analysis also suggests Basilemys, Jiangxichelys and ‘Zangerlia’ form a monophyletic group. Our new finding increases the known diversity of nanhsiungchelyids in southern China.

Keywords: Nanhsiungchelyidae, Late Cretaceous, phylogeny, Ganzhou Basin, China

Xianyuechelys yingliangi gen. et sp. nov.

 

Yuzheng Ke, Kecheng Niu, Paul Rummy, Haiyan Tong,Jinfeng Hu and Fenglu Han. 2024. Xianyuechelys yingliangi: A New nanhsiungchelyid Turtle from the Late Cretaceous of Ganzhou Basin, China. Journal of Systematic Palaeontology. 22(1); 2346838. DOI: 10.1080/14772019.2024.2346838

  Researchgate.net/publication/381306467_Xianyuechelys_yingliangi_a_new_nanhsiungchelyid_turtle_from_the_Late_Cretaceous_of_Ganzhou_Basin_China

[Paleontology • 2023] Proadocus hadongensis • The First adocid Turtle (Cryptodira: Pan-Trionychia) in South Korea (Lower Cretaceous) and the early Evolution of the Adocidae

Proadocus hadongensis

 Kim, Lee, Ko, Park, Kim, Lee, Jung & Kong, 2023

 DOI: 10.1016/j.cretres.2023.105665  

 twitter.com/asprosaurus 

  twitter.com/usikpaleoart

 

Abstract

An adocid turtle was collected from the Lower Cretaceous Hasandong Formation, representing the first occurrence of the Adocidae in South Korea. The specimens consist of moderately preserved hard shells (carapace and plastron) with a limb bone (humerus). They turned out to be a new taxon named Proadocus hadongensis, gen. et sp. nov., characterized by combining synapomorphic characters of adocids and primitive characters ancestrally retained from basal pantrionychians. The pattern of marginal scales extension and pygal shape are shared with Sinaspideretes wimani and Basilochelys macrobios, the basal pantrionychian taxa of the Late Jurassic–Early Cretaceous in Southeast Asia. A cladistic analysis places it as the most basal taxon in Adocidae. Such phylogenetic position of Proadocus involves important implications about the origin and early evolution of the Adocidae. First, Proadocus supports the Southeast Asian origin of this family. Secondly, a new paleobiogeographic analysis, including Proadocus in Korea, requests a new interpretation of the adocid diversification and dispersion in East Asia during the Early Cretaceous.

Testudines Batsch, 1788 

Cryptodira Cope, 1868 

Pan-Trionychia Hummel, 1929 

Adocusia Danilov and Parham, 2006 

Adocidae Cope, 1870 

Proadocus hadongensis, gen. et sp. nov.

Do Hyeon Kim, Yuong-Nam Lee, Hyejin Ko, Jin-Young Park, Su-Hwan Kim, Sungjin Lee, Seung-Ho Jung and Dal-Yong Kong. 2023. The First adocid Turtle in South Korea (Lower Cretaceous) and the early Evolution of the Adocidae. Cretaceous Research. 151; 105665. DOI: 10.1016/j.cretres.2023.105665 

  twitter.com/asprosaurus/status/1693409568137920962

  twitter.com/usikpaleoart/status/1693447585246192093

   

[Paleontology • 2023] Titanochelon schleichi • A New Species of A Giant Tortoise (Cryptodira: Testudinidae) from Sandelzhausen (MN5, Burdigalian/Langhian boundary, Early/Middle Miocene, South Germany)

Titanochelon schleichi 

Pappa, Vlachos & Moser, 2023

DOI: 10.1002/ar.25280  

 twitter.com/AnatRecord

Abstract

We describe a new species of a giant tortoise of the genus Titanochelon from the locality of Sandelzhausen in south Germany (MN5, Burdigalian/Langhian boundary, Early/Middle Miocene). The material comprises at least two different individuals, one of which is a male individual preserving large parts of the carapace and plastron and several appendicular elements. The second individual is quite fragmented, preserving parts of the bridge and the posterior rim of the carapace. The new species, Titanochelon schleichi sp. nov., is the first species of a giant tortoise named from Germany and allows reconstructing an important diversity and expansion of titanochelones in the Western Palaearctic during the earlier parts of the Neogene.

Keywords: gigantism, shell, Testudinidae, turtles

Titanochelon schleichi sp. nov.

 

Irena Pappa, Evangelos Vlachos and Markus Moser. 2023. A New Species of A Giant Tortoise from Sandelzhausen (MN5, Burdigalian/Langhian boundary, Early/Middle Miocene, South Germany). The Anatomical Record. DOI: 10.1002/ar.25280 

  twitter.com/AnatRecord/status/1677286338410823680

 twitter.com/yatachelys/status/1673661704511651844

[Paleontology • 2023] Astrochelys rogerbouri • Ancient DNA elucidates the Lost World of western Indian Ocean Giant Tortoises and reveals A New Extinct Species from Madagascar

Top: Madagascar, from left to right, †Aldabrachelys abrupta, †Al. grandidieri, Pyxis planicauda, P. arachnoides, †Astrochelys rogerbouri n. sp., As. yniphora, and As. radiata. 
Center: Granitic Seychelles (extinct), Aldabra, Al. gigantea.

Kehlmaier, Graciá, Ali, Campbell, Chapman, Deepak, ... et Fritz, 2023

DOI: 10.1126/sciadv.abq2574 senckenberg.de

Artwork: Michal Rössler; photo of Al. gigantea: Massimo Delfino.

Abstract

Before humans arrived, giant tortoises occurred on many western Indian Ocean islands. We combined ancient DNA, phylogenetic, ancestral range, and molecular clock analyses with radiocarbon and paleogeographic evidence to decipher their diversity and biogeography. Using a mitogenomic time tree, we propose that the ancestor of the extinct Mascarene tortoises spread from Africa in the Eocene to now-sunken islands northeast of Madagascar. From these islands, the Mascarenes were repeatedly colonized. Another out-of-Africa dispersal (latest Eocene/Oligocene) produced on Madagascar giant, large, and small tortoise species. Two giant and one large species disappeared c. 1000 to 600 years ago, the latter described here as new to science using nuclear and mitochondrial DNA. From Madagascar, the Granitic Seychelles were colonized (Early Pliocene) and from there, repeatedly Aldabra (Late Pleistocene). The Granitic Seychelles populations were eradicated and later reintroduced from Aldabra. Our results underline that integrating ancient DNA data into a multi-evidence framework substantially enhances the knowledge of the past diversity of island faunas.

 Top: Madagascar, from left to right, †Aldabrachelys abrupta, †Al. grandidieri, Pyxis planicauda, P. arachnoides, †Astrochelys rogerbouri n. sp., As. yniphora, and As. radiata. 
Center: Granitic Seychelles (extinct), Aldabra, Al. gigantea.
Bottom: Mascarenes, from left to right, †Cylindraspis indica (Réunion), †C. inepta, †C. triserrata (both Mauritius), †C. vosmaeri, and †C. peltastes (both Rodrigues).

Sizes to scale, corresponding to reported maximum SCLs. 

Artwork: Michal Rössler; photo of Al. gigantea: Massimo Delfino.

Top: Madagascar, from left to right, †Aldabrachelys abrupta, †Al. grandidieri, Pyxis planicauda, P. arachnoides, †Astrochelys rogerbouri n. sp., As. yniphora, and As. radiata. Center: Granitic Seychelles (extinct), Aldabra, Al. gigantea.

Artwork: Michal Rössler; photo of Al. gigantea: Massimo Delfino.

Astrochelys rogerbouri n. sp.

 

 Diagnosis: A large-sized extinct tortoise species of the genus Astrochelys with an estimated SCL of 50 cm, only known from a single tibia. Astrochelys rogerbouri n. sp. can be separated from the two extant species of the genus by 59 diagnostic mutations in the mitochondrial genome (table S4 and data file S1) and 23 mutations in the reference alignment of four concatenated nuclear loci (HMGB2, HNF1α, R35, and TB73; 3047 bp; table S5 and data file S2). The mitochondrial genome of the new species differs by an uncorrected p distance of approximately 8% from As. radiata and As. yniphora (data file S3); the concatenated nuclear loci of As. rogerbouri n. sp. differ by 0.9 to 1.3% from its two congeners (data file S4).

Etymology: The new species is named for the late Roger Bour (9 July 1947 – 7 March 2020), who was an outstanding herpetologist and expert on western Indian Ocean giant tortoises. Without his pioneering studies and his advice regarding museum specimens, this investigation would not have been possible.

Placement of extinct Malagasy and Mascarene giant tortoises in the tortoise phylogeny. The shown maximum likelihood (ML) topology is based on near-complete mitochondrial genomes (15,537 bp) of all genera and species groups of tortoises (Testudinidae). Codes preceding scientific names are DNA Data Bank of Japan (DDJB)/European Nucleotide Archive (ENA)/GenBank accession numbers or museum numbers. Genus names of extinct taxa bear dagger symbols. Numbers at nodes are thorough bootstrap values and posterior probabilities from a Bayesian analysis yielding the same topology. Asterisks indicate maximum support under both approaches. Colored boxes represent different geographic regions. Inset pictures show the past and present diversity of native tortoise species of the western Indian Ocean (extinct species are in gray). Top: Madagascar, from left to right, †Aldabrachelys abrupta, †Al. grandidieri, Pyxis planicauda, P. arachnoides, †Astrochelys rogerbouri n. sp., As. yniphora, and As. radiata. Center: Granitic Seychelles (extinct), Aldabra, Al. gigantea. Bottom: Mascarenes, from left to right, †Cylindraspis indica (Réunion), †C. inepta, †C. triserrata (both Mauritius), †C. vosmaeri, and †C. peltastes (both Rodrigues). Sizes to scale, corresponding to reported maximum SCLs. Artwork: Michal Rössler; photo of Al. gigantea: Massimo Delfino.

 

Christian Kehlmaier, Eva Graciá, Jason R. Ali, Patrick D.Campbell, Sandra D. Chapman, V. Deepak, Flora Ihlow, Nour-Eddine Jalil, Laure Pierre-Huyet, Karen E. Samonds, Miguel Vences and Uwe Fritz. 2023. Ancient DNA elucidates the Lost World of western Indian Ocean Giant Tortoises and reveals A New Extinct Species from Madagascar.  SCIENCE ADVANCES. 9(2). DOI: 10.1126/sciadv.abq2574

Molecular Archeology: 1200-Year-Old DNA Sequences From Madagascar Lead to the Discovery of an Extinct Tortoise

 senckenberg.de/en/pressemeldungen/molecular-archeology-1200-year-old-dna-sequences-from-madagascar-lead-to-the-discovery-of-an-extinct-tortoise 

twitter.com/geobiodiversity/status/1613466403058638848

[Paleontology • 2022] 100 Million Years of Turtle Paleoniche Dynamics enable the Prediction of Latitudinal Range shifts in A Warming World

 3 fossil turtles: Basilemys, Zangerlia and Axestemys are on the left half, 
the extant turtles Geochelone, Trionyx and Carettochelys on the right half 

in Chiarenza, Waterson, Schmidt, ... et Barrett, 2022. 

DOI: 10.1016/j.cub.2022.11.056  

 twitter.com/AAlechiarenza

illustration by Mauricio Anton. 

Highlights: 

• Non-marine turtles invaded higher paleolatitudes several times in the past

• Non-marine turtles reached their highest latitudes in the Cenomanian and Eocene

• Occupation of high paleolatitudes is projected at extreme emission scenarios

• Human occupation at high latitudes may prevent turtle adaptation to climate change

Summary

Past responses to environmental change provide vital baseline data for estimating the potential resilience of extant taxa to future change. Here, we investigate the latitudinal range contraction that terrestrial and freshwater turtles (Testudinata) experienced from the Late Cretaceous to the Paleogene (100.5–23.03 mya) in response to major climatic changes. We apply ecological niche modeling (ENM) to reconstruct turtle niches, using ancient and modern distribution data, paleogeographic reconstructions, and the HadCM3L climate model to quantify their range shifts in the Cretaceous and late Eocene. We then use the insights provided by these models to infer their probable ecological responses to future climate scenarios at different representative concentration pathways (RCPs 4.5 and 8.5 for 2100), which project globally increased temperatures and spreading arid biomes at lower to mid-latitudes. We show that turtle ranges are predicted to expand poleward in the Northern Hemisphere, with decreased habitat suitability at lower latitudes, inverting a trend of latitudinal range contraction that has been prevalent since the Eocene. Trionychids and freshwater turtles can more easily track their niches than Testudinidae and other terrestrial groups. However, habitat destruction and fragmentation at higher latitudes will probably reduce the capability of turtles and tortoises to cope with future climate changes.

Keywords: Testudinata, climate change, distribution, Late Cretaceous, Eocene, ecological niche modeling

 3 fossil turtles: Basilemys, Zangerlia and Axestemys are on the left half,
 the extant turtles Geochelone, Trionyx and Carettochelys on the right half 

illustration by Mauricio Anton

 

Alfio Alessandro Chiarenza, Amy M. Waterson, Daniela N. Schmidt, Paul J.Valdes, Chris Yesson, Patricia A. Holroyd, Margaret E. Collinson, Alexander Farnsworth, David B. Nicholson, Sara Varela and Paul M. Barrett. 2022. 100 Million Years of Turtle Paleoniche Dynamics enable the Prediction of Latitudinal Range shifts in A Warming World. Current Biology. In Press

DOI: 10.1016/j.cub.2022.11.056 

  twitter.com/AAlechiarenza/status/1605608429241901058

[Paleontology • 2022] Chrysemys corniculata • A New Species of Chrysemys (Testudines: Emydidae: Deirochelyinae) from the latest Miocene-Early Pliocene of Tennessee, USA and Its Implications for the Evolution of Painted Turtles

Chrysemys corniculata

Jasinski, 2022

DOI: 10.1093/zoolinnean/zlac084

 facebook.com/StevenJasinski

reconstruction by Sergey Krasovskiy.

 

Abstract

Chrysemys, commonly known as painted turtles, have the largest native biogeographic range of all North American turtles. The presence of a new species, Chrysemys corniculata sp. nov., in the Late Hemphillian-Early Blancan North American Land Mammal Age (latest Miocene-Early Pliocene) of Tennessee provides further data on the evolution of Chrysemys, deirochelyines and emydids. The new fossil species lies basally in Deirochelyinae and suggests that either Chrysemys represents a basal deirochelyine morphology and is one of the oldest genera in the family, or that similar basal morphologies have evolved multiple times throughout deirochelyine evolution. Its occurrence at the same time as Chrysemys picta, during the Hemphillian-Early Blancan, a time of high biodiversity in emydid turtles, suggests either multiple species of Chrysemys during the Late Hemphillian-Early Blancan (at least one in the mid-west and one farther east), or multiple lineages with basal morphologies during this time. Early fossil deirochelyines occur after the greenhouse conditions of the Eocene and the Mid-Miocene Climatic Optimum. Vicariance led to deirochelyines becoming more speciose, including the occurrence of C. corniculata, after the Mid-Miocene Climatic Optimum, potentially suggesting cooler temperatures aided in the evolution of the subfamily and their speciation during the Hemphillian and into the Early Blancan.

Steven E. Jasinski. 2022. A New Species of Chrysemys (Emydidae: Deirochelyinae) from the latest Miocene-Early Pliocene of Tennessee, USA and Its Implications for the Evolution of Painted Turtles. Zoological Journal of the Linnean Society, zlac084. DOI: 10.1093/zoolinnean/zlac084

 facebook.com/StevenJasinski/posts/10128930247169654

[Paleontology • 2022] Leviathanochelys aenigmatica • A Gigantic Bizarre Marine Turtle (Testudines: Chelonioidea) from the Middle Campanian (Late Cretaceous) of South-western Europe

Leviathanochelys aenigmatica 

Castillo-Visa, Luján, Galobart & Sellés, 2022

DOI: 10.1038/s41598-022-22619-w

Abstract

Marine turtles were common in the subtropical Upper Cretaceous epi-continental seas that once washed the coasts of the ancient European archipelago. But unlike its contemporaneous faunas from North America, in Europe no taxon surpassed the 1.5 m shell-length. Here, the remains of a new large marine turtle, Leviathanochelys aenigmatica gen. et sp. nov., from the Middle Campanian of the Southern Pyrenees are described. Anatomical and histological evidence concur in identifying the specimen as a basal chelonioid. The new taxon autapomorphically differs from other marine turtles by possessing an additional process on the anteromedial side of the pelvis, and an acetabulum directed strongly ventrally. Based on the pelvis size, it is likely that Leviathanochelys was as large as Archelon, thus becoming one of the largest marine turtles found to ever exist. The large body size of the new taxon could have evolved as a response to the unique habitat conditions of the European Cretaceous archipelago seas. The presence of the accessory pubic process further suggests the occurrence of an additional insertion point of the Musculus rectus abdominis, which together with the paleohistologic evidences support the hypothesis that the new taxon had an open marine pelagic lifestyle.

   

Systematic palaeontology

Testudines Batsch, 1788.

Cryptodira Cope, 1868.

Chelonioidea Baur, 1893.

Leviathanochelys aenigmatica gen. et sp. nov.

Etymology: The generic name is composed of the following words: Leviathan, in reference to the Biblical marine beast, in allusion to the body size of the new species; and chelys, Latinized name from the ancient Greek χέλυς (“khélūs” meaning turtle in feminine gender). The specific nomination aenigmatica, Latinized adjective from the Greek noun αἴνιγμα (“aínigma” meaning enigma, conundrum or riddle) is in reference to the peculiar anatomical characteristics of its pelvis and carapace.

 

Type locality and age: Cal Torrades, Coll de Nargó (Lleida Province, Catalonia, North-eastern Spain). Lower part of the Perles Formation, Middle Campanian, Upper Cretaceous.

Diagnosis: Large-sized basal chelonioid defined by the following and unique combination of characters: reduction of the costal plates ossification without a sutural contact between costals and peripherals; carapacial plate margins (costals 5–8 and neurals 5–8) finely sutured; hexagonal/octagonal neural plates, longer than wide, that prevent the costals 6–7 from contacting one another; posterior costal plates that are rectangular-shaped, much wider than long; oval articular area of the ilium, located near the lateral margin of the right costal 8; H-shaped pelvis; enlarged and flat lateral pubic process; conspicuously ornamented, textured surface surrounding the acetabular region; extremely elongated iliac neck; and the absence of carapacial scute sulci, keels, or ornamentation on the external part of the carapace, and absence of the ilium’s posterior notch. Leviathanochelys aenigmatica is further diagnosed by having two autapomorphic characters as follows: accessory process on the anteromedial margin of the pubis; and acetabulum strongly ventrolaterally directed.

Oscar Castillo-Visa, Àngel H. Luján, Àngel Galobart and Albert Sellés. 2022. A Gigantic Bizarre Marine Turtle (Testudines: Chelonioidea) from the Middle Campanian (Late Cretaceous) of South-western Europe. Scientific Reports. 12: 18322. DOI: 10.1038/s41598-022-22619-w

https://phys.org/news/2022-11-fossil-largest-marine-turtles.html

     

[Herpetology • 2021] A Large and Unusually Thick-shelled Turtle Egg (Cryptodira: Nanhsiungchelyidae) with Embryonic Remains from the Upper Cretaceous of China

in Ke, Wu, Zelenitsky, ... et Han, 2021

DOI: 10.1098/rspb.2021.1239

Illustration: Masato Hattori.

 

Abstract

Turtle eggs containing embryos are exceedingly rare in the fossil record. Here, we provide the first description and taxonomic identification, to our knowledge, of a fossilized embryonic turtle preserved in an egg, a fossil recovered from the Upper Cretaceous Xiaguan Formation of Henan Province, China. The specimen is attributed to the Nanhsiungchelyidae (Pan-Trionychia), an extinct group of large terrestrial turtles (possibly the species Yuchelys nanyangensis). The egg is rigid, spherical, and is one of the largest and thickest shelled Mesozoic turtle eggs known. Importantly, this specimen allowed identification of other nanhsiungchelyid egg clutches and comparison to those of Adocidae, as Nanhsiungchelyidae and Adocidae form the basal extinct clade Adocusia of the Pan-Trionychia (includes living soft-shelled turtles). Despite the differences in habitat adaptations, nanhsiungchelyids (terrestrial) and adocids (aquatic) shared several reproductive traits, including relatively thick eggshells, medium size clutches and relatively large eggs, which may be primitive for trionychoids (including Adocusia and Carrettochelyidae). The unusually thick calcareous eggshell of nanhsiungchelyids compared to those of all other turtles (including adocids) may be related to a nesting style adaptation to an extremely harsh environment.

Keywords: Nanhsiungchelyidae, China, thick egg, shell, Upper Cretaceous, embryo, turtle egg

Systematic palaeontology: 

Order Testudines Linnaeus, 1758

Infraorder Cryptodira Cope, 1868

Superfamily Trionychoidae Fitzinger, 1826

Family Nanhsiungchelyidae Yeh, 1966

Genus and species indet.

A Nanhsiungchelyid turtle egg containing an embryo. 

Material. CUGW EH051, a complete egg containing embryonic remains.

Locality and horizon. Specimen CUGW EH051 was collected in Neixiang County, Nanyang City, Henan Province, China (electronic supplementary material, figure S1); Xiaguan Formation, Upper Cretaceous. ....

 

    

Illustration: Masato Hattori.

Yuzheng Ke, Rui Wu, Darla K. Zelenitsky, Don Brinkman, Jinfeng Hu, Shukang Zhang, Haishui Jiang and Fenglu Han. 2021. A Large and Unusually Thick-shelled Turtle Egg with Embryonic Remains from the Upper Cretaceous of China. Proceedings of the Royal Society B. DOI: 10.1098/rspb.2021.1239

 phys.org/news/2021-08-thick-shelled-turtle-egg-embryo-cretaceous.html

 livescience.com/rare-turtle-embryo-from-dinosaur-age.html

[Paleontology • 2021] Adocus kohaku • A New Species of Aquatic Turtle (Testudines: Cryptodira: Adocidae) from the Late Cretaceous of Kuji, Iwate Prefecture, Northeast Japan, with Special References to the Geological Age of the Tamagawa Formation (Kuji Group)

 Adocus kohaku

Hirayama, Sonoda, Uno, Horie, Tsutsumi, Sasaki, Mitsuzuka & Takisawa, 2021

  medwinpublishers.com/IJPBP 

Illustration: Oda Takashi facebook.com/studiocorvo 

Abstract 

A nearly complete shell of the genus Adocus (Adocidae; Pan-Trionychia; Cryptodira; Testudines) was collected from the late Cretaceous (Turonian) Tamagawa Formation of Kuji Group at Kuji City, Iwate Prefecture, northeast Japan. This turtle shows unique features such as the loss of cervical scute, extreme expansion of marginal scutes overlying costal plates, and exclusion of the humeral- pectoral sulcus from entoplastron. Thus,  Adocus kohaku is erected as a new species. As A. kohaku shows most derived position of A. kohaku within this genus, morphological diversity of the genus Adocus seems to have occurred rather early in its evolution in Eastern Asia. 

Keywords: Adocus kohaku sp. nov.; Cretaceous; Kuji Group; Reptilia; Testudines; U-Pb Dating

Systematic Paleontology

Testudines Batsch, 1788

Cryptodira Cope, 1868

Pan-Trionychia Hummel, 1929

Adocidae Cope, 1870

Type Genus. Adocus Cope, 1868

Known Distribution. Early Cretaceous to Eocene of Asia and Late Cretaceous to Paleocene of North America.

Genus Adocus Cope, 1868 

Type Species. Adocus beatus (Leidy, 1865) 

Known Distribution. Early Cretaceous to Eocene of Asia and Late Cretaceous to Paleocene of North America. 

: Turtle shell of  Adocus kohaku sp. nov., holotype, KAM 01.
A, carapace in dorsal view; B, plastron in ventral view; C, plastron in dorsal view. Red lines show scute sulci on shell surface.

Adocus kohaku, New Species

Diagnosis. Adocus with cervical scute completely lost; fifth to tenth marginal scutes medially enlarged, overlying at least distal half of second to seventh costal plates; three pairs of inframarginals. 

Etymology. Named after Japanese name of amber as this fossil was associated with numerous ambers. 

    

Conclusion: 

A nearly complete shell of the genus Adocus (Adocidae; Trionychia; Cryptodira; Testudines) was collected from the late Cretaceous (Turonian) Tamagawa Formation of Kuji Group at Kuji city, Iwate Prefecture, northeast Japan. This turtle shows unique features such as the loss of cervical scute, extreme expansion of marginal scutes overlying costal plates, exclusion of the humero-pectoral sulcus from entoplastron, and three pairs of inframarginals. Thus, A. kohaku is proposed as a new species. Additional remains of A. kohaku suggest this species had carapace length of at least a 60 cm long, the largest among Adocus in Asia. As A. kohaku is a derived taxon within this genus, its occurrence in the early Late Cretaceous suggests early development of morphological diversifications within this genus, as previously proposed for the Nanhsiungchelyidae. Occurrences of both most basal (A. sengokuensis) and most derived (A. kohaku) taxa from Japan implies eastern Asia was the center of diversification of this clade. 

Ren Hirayama, Teppei Sonoda, Hikaru Uno, Kenji Horie, Yukiyasu Tsutsumi, Kazuhisa Sasaki, Shunsuke Mitsuzuka and Toshio Takisawa. 2021. Adocus kohaku, A New Species of Aquatic Turtle (Testudines: Cryptodira: Adocidae) from the Late Cretaceous of Kuji, Iwate Prefecture, Northeast Japan, with Special References to the Geological Age of the Tamagawa Formation (Kuji Group). International Journal of Paleobiology & Paleontology. medwinpublishers.com/IJPBP

 facebook.com/studiocorvo/posts/3113249255564881

Researchgate.net/publication/348662272_Adocus_kohaku_A_New_Species_of_Aquatic_Turtle_from_the_Late_Cretaceous_of_Kuji_Iwate_Japan

https://medwinpublishers.com/IJPBP/adocus-kohaku-a-new-species-of-aquatic-turtle-testudines-cryptodira-adocidae-from-the-late-cretaceous-of-kuji-iwate-prefecture-northeast-japan-with-special-references-to-the-geological-age-of-the-tamagawa-formation-kuji-group.pdf

       

[Herpetology • 2021] Discovery of the first Mascarene Giant Tortoise (Testudinidae: Cylindraspis) Nesting Site on Rodrigues Island, Indian Ocean

 Rodrigues giant tortoises on the Plaine Corail, 
based on a unique stuffed Saddleback Tortoise Cylindraspis vosmaeri male (MNHN 1883.558; centre left) and a complete carapace of Domed Tortoise C. peltastes (MNHN 7831; front). The Rodrigues rail Erythromachus leguati, a predator of tortoise eggs and young, forages amongst the tortoises. 

in Hume, Griffiths, ... et Bour, 2021. 

  biotaxa.org/HN

Illustration: Julian Pender Hume

Abstract

Five species of giant tortoise (genus Cylindraspis) once occurred in huge abundance on the Mascarene Islands of Mauritius, Réunion, and Rodrigues. They disappeared after colonisation of the island by humans in the 17th and 18th centuries, primarily due to over-hunting and predation of eggs and young by introduced pigs and cats. So rapid was their extinction that virtually nothing is known about their life history, especially nesting and egg-laying behaviour. Here we report the discovery on Rodrigues of the first Mascarene tortoise-nesting site, which contained intact nesting chambers, complete egg clutches and fossil remains of a known native predator of tortoise eggs. We further compare the nesting behaviour with the giant tortoises of Aldabra Atoll in the Seychelles and the Galapagos Archipelago in Ecuador and provide details of the decline and extinction of Mascarene tortoises, most notably those of Rodrigues, for which good historical records exist. 

Keywords: Mauritius, Réunion, Aldabrachelys gigantea, Chelonoidis, egg chamber, clutches, extinction 

A complete clutch of Cylindraspis vosmaeri eggs removed intact from PB4 on Rodrigues Island. The clutch contains 13 eggs. 

Scale bar = 100 mm.

A reconstruction of Rodrigues giant tortoises on the Plaine Corail, based on a unique stuffed Saddleback Tortoise Cylindraspis vosmaeri male (MNHN 1883.558; centre left) and a complete carapace of Domed Tortoise C. peltastes (MNHN 7831; front) (see Bour et al. 2014a). The Rodrigues rail Erythromachus leguati, a predator of tortoise eggs and young, forages amongst the tortoises. 

Illustration by Julian Pender Hume.

Two species of extinct giant tortoises, Cylindraspis vosmaeri (larger, saddlebacked) and C. peltastes (smaller, domed) in their native habitat on Rodrigues Island in the late 1600s when accounts indicate the herds of tortoises were so large and dense that it was possible to walk for long distances on their backs without touching the ground (Leguat 1707). 

Painting by Julian Pender Hume (from Griffiths et al. 2013).

Julian Pender Hume, Owen Griffiths, Aurèle Anquetil Andre, Arnaud Meunier and Roger Bour. 2021. Discovery of the first Mascarene Giant Tortoise Nesting Site on Rodrigues Island, Indian Ocean (Testudinidae: Cylindraspis). Herpetology Notes. 14; 103-116. biotaxa.org/HN/article/view/62722/64867

Researchgate.net/publication/348371293_Discovery_of_the_first_Cylindraspis_nesting_site_on_Rodrigues_Island