Plateosaurus trossingensis E. Fraas, 1913

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

Plateosaurus trossingensis E. Fraas, 1913

Holotype.

SMNS 13200 , nearly complete skeleton with complete but slightly distorted skull (Fig. 19 B ), cervical vertebrae and ribs, dorsal vertebrae and ribs, sacral vertebrae, and 39 caudal vertebrae with 28 hemal arches; both scapulae; complete right forelimb with nearly complete manus missing only phalanx 1 of digit V and only preserving distal carpal I; left radius, left metacarpal II, complete digit II of the left manus, left distal carpal 1, and first phalanx of manual digit III; both ilia, ischia, and pubes; and complete right hindlimb and nearly complete left one only missing ungual of pedal digit III ( Schaeffer 2024).

Type locality.

Slope (“ Rutschete ”) east of Obere Mühle at Deibhalde, east of Trossingen, Tuttlingen district, Baden-Württemberg.

Type horizon.

“ Untere Saurierschicht, ” Trossingen Formation, Middle Keuper Subgroup. Age: Late Triassic (Norian: Sevatian).

Referred material.

Includes more than 80 relatively complete skeletons ( Schaeffer 2024) and many isolated bones. Regalado Fernández et al. (2023) provided a detailed inventory of the material housed at GPIT.

Diagnosis.

Distinguished by the following combination of features: presence of accessory lamina separating postzygapophysis from posterior ‘ chono’s (= postzygapophyseal centrodiapophyseal fossa); anterior caudal vertebrae with prezygodiapohyseal laminae; deltopectoral crest occupying 30–50 % of length of humerus; metacarpals II and III with deep distal extensor pits; ischial peduncle much shorter than pubic peduncle; posterolateral process of distal end of tibia flaring laterally and backing fibula; astragalus with convex posterior margin; and ungual phalanx of pedal digit I longer than all non-terminal phalanges but shorter than metatarsal I ( Schaeffer 2024 a, b; Fig. 13 A, B ).

Comments.

Meyer (1837) named the type species of Plateosaurus , P. engelhardti , based on postcranial bones including the lectotype UEN 552 , an incomplete sacrum with three vertebrae, from the Feuerletten (Trossingen Formation) of Heroldsberg near Nürnberg, Bavaria ( Moser 2003). Over time, this specimen became considered non-diagnostic. Galton (2012) successfully petitioned the International Commission for Zoological Nomenclature to designate Plateosaurus trossingensis , based on the excellently preserved skeleton SMNS 13200 , as the type species of Plateosaurus and to set aside P. engelhardti (ICZN Opinion 2435, 2019).

Galton (1984, 1985 b) and Prieto-Márquez and Norell (2011) have documented the structure of a fully disarticulated skull of a well-preserved skeleton (identified by the latter authors as Plateosaurus erlenbergiensis, AMNH FARB 6180 ) in detail. Lallensack et al. (2021) observed considerable intra- or interspecific variation in cranial features among specimens from Frick, Halberstadt, and Trossingen.

References.

Meyer (1837), F. Huene (1926 a, 1932 b), Galton (1984, 1985 b, 2001 a, b), Yates (2003), Prieto-Márquez and Norell (2011), ICZN (2019), Lallensack et al. (2021), Schaeffer (2024).

Figures

Figure 13. A, B. Archosauriform Zanclodon laevis, holotype (SMNS 6045), incomplete left maxilla with attached bone fragment in lateral (A) and medial (B) view. Scale bar: 3 cm. C, D. Phytosaur Calamosuchus arenaceus comb. nov., holotype (SMNS 80737), mandible fragment in lateral views. Scale bar: 3 cm.

Figure 19. Reptiles from the Middle Keuper Subgroup. A. Pseudosuchian Apatosuchus orbitoangulatus, holotype (SMNS 12353 b), disarticulated cranial bones. Scale bar: 1 cm. B. Plateosaurid sauropodomorph Plateosaurus trossingensis, holotype (SMNS 13200), skull in lateral view. Length of skull 33 cm. C. Coelophysid theropod Procompsognathus triassicus, holotype (SMNS 12591), partial postcranial skeleton in ventral view. Scale bar: 5 cm.