Pappochelys rosinae Schoch & Sues, 2015

Sues, Hans-Dieter & Schoch, Rainer R., 2025, Synopsis of the Triassic reptiles from Germany, Fossil Record 28 (2), pp. 411-483 : 411-483

Pappochelys rosinae Schoch & Sues, 2015

Holotype.

SMNS 91360 , incomplete, partially articulated postcranial skeleton comprising the nearly complete caudal vertebral series (except for the distal end of the tail), right ilium and pubis, right femur and tibia, partial pes, two sacral and eight dorsal vertebrae, dorsal ribs, gastralia, seven cervical vertebrae (including the atlas but not the axis), and various cranial elements (Fig. 10 A ). The somewhat scattered remains are exposed on a larger block and several smaller ones, one of which preserves two dissociated cervical vertebrae.

Type locality.

Schumann Quarry, near Eschenau, Vellberg municipality, Schwäbisch Hall district, Baden-Württemberg.

Type horizon.

Untere Graue Mergel, Bed 6, Erfurt Formation, Lower Keuper Subgroup. Age: Middle Triassic (Ladinian: Longobardian).

Referred material.

SMNS 90013 , formally designated by Schoch and Sues (2015) as the paratype, complements the holotype in preserving much of the skull. It comprises the remains of a disarticulated skeleton of a juvenile individual: much of skull roof exposed in ventral view, part of left humerus, possibly right femur, dorsal vertebrae, several dorsal ribs, gastralia, and bones of the carpus and manus. Schoch and Sues (2018 a) provided a detailed inventory of other referred specimens.

Diagnosis.

Diagnosed by the following combination of features: skull proportionately small; parietal broad transversely, with distinct occipital flange and without parietal foramen; frontal narrow transversely; marginal teeth small, peg-like; diastema at contact between premaxilla and maxilla; parietal and squamosal framing much of supratemporal fenestra; jugal with long, slender anterior process and very short posterior process; infratemporal fenestra wide open ventrally; dorsal ribs anteroposteriorly broad, T-shaped in cross-section, and with distinct sculpturing of ridges and grooves on dorsal surface; gastralia paired, robust, with ridged external surfaces and frequently with spike-like lateral projections; apparently serial partial fusion of some gastralia; tail slender, comprising some 50 % of total length; scapula with tall, slender dorsal process and rounded ‘ acromial’ flange; humerus with two distal condyles for articulation with radius and ulna; ilium with long postacetabular and without preacetabular process; pubis with distinct lateral (pectineal) process; and femur with sigmoidal curvature ( Schoch and Sues 2018 b).

Comments.

Pappochelys rosinae is the earliest known undisputed stem-turtle. Schoch and Sues (2018 a) and Schoch et al. (2019) presented a detailed description of the material known at the time. Lyson and Bever (2020) supported the phylogenetic position of Pappochelys as a stem-turtle.

References.

Schoch and Sues (2015, 2018 a), Schoch et al. (2019), Lyson and Bever (2020).

Figures

Figure 10. Reptiles from the Lower Keuper Subgroup. A. Stem-turtle Pappochelys rosinae, holotype (SMNS 91360), partial postcranial skeleton. Scale bar: 1 cm. B. Rhynchocephalian Wirtembergia hauboldae, holotype (SMNS 91313), right maxilla in lateral view. Scale bar: 2 mm. C. Doswelliid archosauriform Jaxtasuchus salomoni (SMNS 91083), maxillary tooth. Scale bar: 1 mm. D. Colognathid Quasicolognathus eothen, holotype (SMNS 97019), left maxilla and prefrontal and possible palatine in lateral view. Scale bar: 2 mm. E. Doswelliid archosauriform Jaxtasuchus salomoni (SMNS 91085), lateral dorsal osteoderm in dorsal view. Scale bar: 1 cm.