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A review of Shamosuchus and Paralligator (Crocodyliformes, Neosuchia) from the Cretaceous of Asia.

Turner AH - PLoS ONE (2015)

Bottom Line: Rugosuchus and Batrachomimus are sister taxa to Paralligator.Paralligatoridae is closely related to Theriosuchus, hylaeochampsids and a speciose Allodaposuchus clade, which together are the sister group of Borealosuchus plus Crocodylia.These results support the presence of a diverse clade in eastern Asia and western North America throughout the Cretaceous with origins in the Late Jurassic.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, United States of America.

ABSTRACT
The crocodyliform Shamosuchus is known from numerous Late Cretaceous localities in southern and eastern Mongolia and fragmentary remains from Uzbekistan. Seven species of Shamosuchus have been named from six localities in Mongolia and three in Uzbekistan. Six species originally described as Paralligator were later referred to Shamosuchus. Only the type species, Shamosuchus djadochtaensis has been examined in detail. Many of the named species of Shamosuchus show striking similarity in size and cranial morphology but most are based on partial remains suggesting that the true species diversity is overestimated. A review of all species referred to Shamosuchus recognizes three valid taxa: Shamosuchus djadochtaensis, S. gradilifrons, and S. major. Shamosuchus sungaricus, S. borealis, and S. karakalpakensis are nomena dubia, whereas S. ancestralis, S. ulgicus, S. tersus, and S. ulanicus are junior subjective synonyms of S. gradilifrons. Phylogenetic analysis of 318 phenotypic characters recovers a Paralligatoridae clade consisting of Shamosuchus, Rugosuchus, Batrachomimus, Glen Rose Form, and Wannchampsus. Shamosuchus is non-monophyletic: S. djadochtaensis is near the base of Paralligatoridae whereas S. gradilifrons + S. major are the most deeply nested. The name Paralligator is resurrected for this clade. Rugosuchus and Batrachomimus are sister taxa to Paralligator. Paralligatoridae is closely related to Theriosuchus, hylaeochampsids and a speciose Allodaposuchus clade, which together are the sister group of Borealosuchus plus Crocodylia. These results support the presence of a diverse clade in eastern Asia and western North America throughout the Cretaceous with origins in the Late Jurassic.

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AMNH FARB 6412 (holotype), Shamosuchus djadochtaensis, Djadokhta Fm., Campanian, Mongolia.Photographs in A, dorsal, B, ventral, C, left lateral, D, occipital views.
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pone.0118116.g002: AMNH FARB 6412 (holotype), Shamosuchus djadochtaensis, Djadokhta Fm., Campanian, Mongolia.Photographs in A, dorsal, B, ventral, C, left lateral, D, occipital views.

Mentions: Mook [1] described Shamosuchus djadochtaensis on the basis of an incomplete and not entirely well preserved skull (AMNH FARB 6412, Fig. 2) from the Flaming Cliffs locality (Djadokhta Fm., Mongolia). Mook’s description was quite short and lacked much in the way of anatomical details. A second, much more complete specimen (IGM 100/1195) found at Ukhaa Tolgod is a nearly complete skull (Fig. 3) and associated postcranial skeleton, including representative osteoderms from across the entire dermal shield (i.e., dorsal, ventral, and appendicular). This specimen provided the basis of a much more detailed description of this species, accompanied by extensive figuring of the holotype and referred specimen [5]. Thus, there is little need to amend this description.


A review of Shamosuchus and Paralligator (Crocodyliformes, Neosuchia) from the Cretaceous of Asia.

Turner AH - PLoS ONE (2015)

AMNH FARB 6412 (holotype), Shamosuchus djadochtaensis, Djadokhta Fm., Campanian, Mongolia.Photographs in A, dorsal, B, ventral, C, left lateral, D, occipital views.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4340866&req=5

pone.0118116.g002: AMNH FARB 6412 (holotype), Shamosuchus djadochtaensis, Djadokhta Fm., Campanian, Mongolia.Photographs in A, dorsal, B, ventral, C, left lateral, D, occipital views.
Mentions: Mook [1] described Shamosuchus djadochtaensis on the basis of an incomplete and not entirely well preserved skull (AMNH FARB 6412, Fig. 2) from the Flaming Cliffs locality (Djadokhta Fm., Mongolia). Mook’s description was quite short and lacked much in the way of anatomical details. A second, much more complete specimen (IGM 100/1195) found at Ukhaa Tolgod is a nearly complete skull (Fig. 3) and associated postcranial skeleton, including representative osteoderms from across the entire dermal shield (i.e., dorsal, ventral, and appendicular). This specimen provided the basis of a much more detailed description of this species, accompanied by extensive figuring of the holotype and referred specimen [5]. Thus, there is little need to amend this description.

Bottom Line: Rugosuchus and Batrachomimus are sister taxa to Paralligator.Paralligatoridae is closely related to Theriosuchus, hylaeochampsids and a speciose Allodaposuchus clade, which together are the sister group of Borealosuchus plus Crocodylia.These results support the presence of a diverse clade in eastern Asia and western North America throughout the Cretaceous with origins in the Late Jurassic.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, United States of America.

ABSTRACT
The crocodyliform Shamosuchus is known from numerous Late Cretaceous localities in southern and eastern Mongolia and fragmentary remains from Uzbekistan. Seven species of Shamosuchus have been named from six localities in Mongolia and three in Uzbekistan. Six species originally described as Paralligator were later referred to Shamosuchus. Only the type species, Shamosuchus djadochtaensis has been examined in detail. Many of the named species of Shamosuchus show striking similarity in size and cranial morphology but most are based on partial remains suggesting that the true species diversity is overestimated. A review of all species referred to Shamosuchus recognizes three valid taxa: Shamosuchus djadochtaensis, S. gradilifrons, and S. major. Shamosuchus sungaricus, S. borealis, and S. karakalpakensis are nomena dubia, whereas S. ancestralis, S. ulgicus, S. tersus, and S. ulanicus are junior subjective synonyms of S. gradilifrons. Phylogenetic analysis of 318 phenotypic characters recovers a Paralligatoridae clade consisting of Shamosuchus, Rugosuchus, Batrachomimus, Glen Rose Form, and Wannchampsus. Shamosuchus is non-monophyletic: S. djadochtaensis is near the base of Paralligatoridae whereas S. gradilifrons + S. major are the most deeply nested. The name Paralligator is resurrected for this clade. Rugosuchus and Batrachomimus are sister taxa to Paralligator. Paralligatoridae is closely related to Theriosuchus, hylaeochampsids and a speciose Allodaposuchus clade, which together are the sister group of Borealosuchus plus Crocodylia. These results support the presence of a diverse clade in eastern Asia and western North America throughout the Cretaceous with origins in the Late Jurassic.

Show MeSH
Related in: MedlinePlus