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International audience; The internal endocranial structures of an undescribed atoposaurid crocodylomorph from the Sao Khua Formation (Cretaceous: Berriasian-Barremian) in the North-East of Thailand are investigated. The specimen is comparable in size and external morphology to Theriosuchus grandinaris Lauprasert et al. 2011 but is preserved with the braincase uncrushed, contrary to the previously described holotype. We document for the first time the internal braincase structures in atoposaurids using synchrotron X-ray micro-computed tomography. The endocast of the braincase, associated nerves and arteries, auditory labyrinth, and cranial pneumatization, although quite deformed, are reconstructed at high resolution and compared to those of extant and fossil crocodylomorphs, representative of different ecological adaptations. This atoposaurid specimen shows an antero-posterior brain curvature and pericerebral spines (new structures), somewhat developed cerebral hemispheres, expanded semicircular canals with a more developed anterior one but an almost straight lateral one, a dorsoventrally expanded pituitary fossa, but also overdeveloped intertympanic diverticula and pharyngotympanic sinuses. The ecologicalsignificance of these structures is explored and, using different proxies and comparisons with extant taxa, we suggest that this specimen likely exhibited a downwardly tilted head posture (by about 10◦) and was sensitive to both low and mid frequencies. Functional comparisons are proposed between this specimen, extinct terrestrial crocodylomorphs (sebecosuchians), extant semi-aquatic crocodilians and aquatic (thalattosuchians) forms. From the morphology of the auditory labyrinth, we infer an enhanced sensitivity to pitching rather than yawing. Several hypotheses are formulated regarding the pneumatization of the skull. These features are discussed in ecological and phylogenetic frameworks. Our results highlight the need to gather new data, especially on altirostral forms, in order to deepen our understanding of the evolution of endocranial structures in crocodylomorphs with different ecological specializations, as well as to integrate them into new phylogenetic approaches.

Nonsrirach, Thanade, Lauprasert, Komsorn (2019): Preliminary report on the genetic structure of Glyphoglossus molossus (Anura: Microhylidae) from the Khorat Plateauı north-eastern Thailand. Journal of Natural History 53 (13): 849-861, DOI: 10.1080/00222933.2019.1618940

Glyphoglossus molossus, is one of the most economically important amphibians in the Khorat Plateau, north-eastern Thailand. It is categorised as a near-threatened species by IUCN due to over-exploi...

International audience; Skull and mandibular elements of a tomistomine crocodilian are described from the late Eocene to early Oligocene lignite seams of Krabi, peninsular Thailand. The Thai tomistomine is a longirostrine form characterized by a rostrum/skull ratio of about 0.6; a mandibular symphysis reaching the level of the eleventh alveolus; a deep participation of the splenial in the symphysis to the level of ninth alveolus; an enlarged fifth maxillary alveolus; long nasals reaching the premaxillae at the level of the fifth maxillary alveolus but not contributing to the external nares; undivided posterior processes of premaxillae; a short prefrontal, excluded by a longer lacrimal from the posteromedial margin of maxillae; vomers visible on the palate. A phylogenetic analysis recovers the Thai specimen among derived tomistomines, on the stem lineage of the extant Tomistoma schlegelii, as a close ally of Maomingosuchus petrolica, a late Eocene tomistomine from southern China. The present recognition of Maomingosuchus sp. in late Eocene Thai deposits expands the distribution of Eocene tomistomines from southern China to the tropics. The origin of Tomistominae in Asia is briefly discussed.; Des éléments crâniens et mandibulaires d’un crocodilien tomistominé sont décrits en provenance de niveaux à lignite de l’Eocène supérieur à Oligocène inférieur de Krabi sur la péninsule Thailandaise. Le tomistominé Thaïlandais est caractérisé par un crâne de type longirostre présentant un ratio rostre/crâne d’environ 0.6 ; une symphyse mandibulaire qui atteint le niveau du onzième alvéole ; une participation profonde du splénial dans la symphyse mandibulaire au niveau du neuvième alvéole ; un cinquième alvéole maxillaire élargi ; les os du nasal qui atteignent les prémaxillaires au niveau du cinquième alvéole maxillaire mais ne participant pas aux narines externes ; des processus postérieurs des prémaxillaires non-divisés ; un préfrontal court, exclu de la marge postéromédiale des maxillaires par un lacrimal plus long ; un vomer visible sur le palais. Une analyse phylogénétique place le spécimen Thaïlandais au sein des tomistominés dérivés, au sein de la lignée de l’actuel Tomistoma schlegelii, et proche de Maomingosuchus petrolica, un taxon de la fin de l’Eocène connu en Chine du sud. La présente découverte de Maomingosuchus sp. dans l’Eocène tardif de Thaïlande étend l’aire de répartition des tomistominés eocènes depuis la Chine du sud jusqu’aux tropiques. L’origine des Tomistominae en Asie est brièvement discutée.

KRABISUCHUS GEN. NOV. Type species: Krabisuchus siamogallicus sp. nov. Etymology: The generic name is based on the locality, ‘Krabi’, in which the holotype was found and the Egyptian ‘souchos’ for crocodile. Diagnosis: As for the species, by monotypy.

Martin, Jeremy E., Lauprasert, Komsorn (2010): A new primitive alligatorine from the Eocene of Thailand: relevance of Asiatic members to the radiation of the group. Zoological Journal of the Linnean Society 158 (3): 608-628, DOI: 10.1111/j.1096-3642.2009.00582.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2009.00582.x

KRABISUCHUS GEN. NOV. Type species: Krabisuchus siamogallicus sp. nov. Etymology: The generic name is based on the locality, 'Krabi', in which the holotype was found and the Egyptian 'souchos' for crocodile. Diagnosis: As for the species, by monotypy., Published as part of Martin, Jeremy E. & Lauprasert, Komsorn, 2010, A new primitive alligatorine from the Eocene of Thailand: relevance of Asiatic members to the radiation of the group, pp. 608-628 in Zoological Journal of the Linnean Society 158 (3) on page 610, DOI: 10.1111/j.1096-3642.2009.00582.x, http://zenodo.org/record/4720050

Lauprasert Komsorn, Cuny Gilles, Buffetaut Éric, Suteethorn Varavudh, Thirakhupt Kumthorn. First occurrences of Atoposaurid Crocodyliforms in the Late Jurassic and Early Cretaceous of the Khorat Plateau, northeastern Thailand. In: Documents des Laboratoires de Géologie, Lyon, n°164, 2008. Mid-Mesozoic life and environments. Cognac (France), June 24th-28th 2008. pp. 59-61.