An Upper Triassic terrestrial vertebrate assemblage from the forgotten Kocury locality (Poland) with a new aetosaur taxon

Abstract

Since 1990, several localities within the Keuper (upper Middle to Upper Triassic) strata in southern Poland have yielded remains of numerous terrestrial vertebrate species. Here we report a new Upper Triassic vertebrate assemblage from the rediscovered Kocury locality. An incomplete theropod dinosaur fibula named Velocipes guerichi described in 1932 was found there.The site was then forgotten and not explored until our excavations initiated in 2012, that yielded material of a lungfish, a proterochersid turtle, and a new typothoracin aetosaur Kocurypelta silvestris gen. et sp. nov. The new taxon is characterized by autapomorphies of the maxilla: an elongated edentulous posterior portion longer than 80% of the posterior maxillary process, a short medial shelf restricted to the posterior portion of the bone, an anteriorly unroofed maxillary accessory cavity, and lack of a distinct groove for choanal recess on the anteromedial surface of the bone. These new finds improve our knowledge on the vertebrate diversity of the Germanic Basin in the Late Triassic, evidencing the presence of yet unrecognized taxa. Additionally, the partial cranial aetosaur material emphasizes the issues with the aetosaurian taxonomy that is focused mostly on the osteoderm morphology.

Skull osteology of Aetosauroides scagliai Casamiquela, 1960 (Archosauria: Aetosauria) from the Late Triassic of Brazil: New insights into the paleobiology of aetosaurs

“…smalli, TTUP 9024;Longosuchus meadei, TMM 31185-84). The alveoli extend toward the posterior portion of the maxilla as in most pseudosuchians, but differing from the condition in erpetosuchids (Benton and Walker, 2002;Nesbitt and Butler, 2013;Ezcurra et al, 2017) and the recentlydescribed aetosaur Kocurypelta silvestris (Czepiński et al, 2021). Nasal: The anterior portions of both nasals are missing in MCN-PV 2347 (Figures 2-5), and these bones have been displaced from their life positions.…”

“…Stagonolepis olenkae (ZPAL AbIII/1996), Desmatosuchus smalli (TTUP 9024;Small, 2002), Longosuchus meadei (TMM 31185-84), Stenomyti huangae (Small and Martz, 2013), and Kocurypelta silvestris (Czepiński et al, 2021). As in other aetosaurs, the medial shelf does not meet its counterpart medially, lacking the palatal process typical of other pseudosuchians (e.g., Nesbitt and Butler, 2012;Mastrantonio et al, 2019).…”

“…In other aetosaurs only two projections are present in the maxilla, with the ventral one being the largest, as is the case in Stenomyti huangae (DMNH 60708) and Desmatosuchus smalli (TTUP 9024). This may also be true for Desmatosuchus spurensis (UMMP V7476), Longosuchus meadei (TMM 31185-84), and Kocurypelta silvestris (Czepiński et al, 2021), although it is difficult to determine given available material.…”

“…The pneumatic cavity is known in several aetosaurs, including Stagonolepis robertsoni (according to Walker, 1961;Small, 2002), Stagonolepis olenkae (Sulej, 2010), Calyptosuchus wellesi (Parker, 2018), Desmatosuchus spurensis (UMMP V7476), Desmatosuchus smalli (TTUP 9024;Small, 2002), and Kocurypelta silvestris (Czepiński et al, 2021). However, in Longosuchus meadei (TMM 31185-84), the pneumatic cavity is not observable in medial view, being oriented toward the anterior region of the antorbital fenestra.…”

“…Recent research on A. scagliai has provided a better understanding of its intraspecific variation Taborda et al, 2013;Taborda et al, 2015;Paes Neto et al, 2021b) and cranial osteology (Brust et al, 2018;Paes Neto et al, 2021a). These and other studies (e.g., Desojo, 2005) have firmly established the Gondwanan A. scagliai as a valid taxon, distinct from the Laurasian S. robertsoni and Calyptosuchus wellesi Ballew, 1985 (contra Heckert andLucas, 2000;Lucas and Heckert, 2001;Heckert and Lucas, 2002), a status recognized in most recent work on the group (e.g., Desojo et al, 2012Desojo et al, , 2013Robertoda-Silva et al, 2014;Heckert et al, 2015;Parker, 2016a,b;Schoch and Desojo, 2016;Ezcurra et al, 2017;Brust et al, 2018;Hoffman et al, 2018;Parker, 2018a,b;Desojo et al, 2020a,b;Marsh et al, 2020;Czepiński et al, 2021;Reyes et al, 2021).…”