Plagiosuchus pustuliferus (Fraas, 1896) von Huene

Damiani, Ross, Schoch, Rainer R., Hellrung, Hanna, Werneburg, Ralf & Gastou, Stéphanie, 2009, The plagiosaurid temnospondyl Plagiosuchus pustuliferus (Amphibia: Temnospondyli) from the Middle Triassic of Germany: anatomy and functional morphology of the skull, Zoological Journal of the Linnean Society 155 (2), pp. 348-373 : 350-351

PLAGIOSUCHUS PUSTULIFERUS ( FRAAS, 1896)

1889 Labyrinthodon sp. Fraas, p. 102, pl. 6, fig. 15, non fig. 16

1896 Plagiosternum pustuliferum Fraas , p. 8

1922 Plagiosuchus pustuliferus (Fraas) von Huene , p. 418, figs 26–28

1922 Plagiosuchus pustuloglomeratus von Huene , p. 425, fig. 29, partim

Comment: A comprehensive list of synonyms and citations to Plagiosuchus pustuliferus in the literature is provided by Hellrung (2003: 115). Hence, the synonymy list above is restricted to changes in the taxon name.

Lectotype: SMNS 55909, a partial interclavicle, described and figured by von Meyer & Plieninger (1844: 67, pl. 9, fig. 8) and Fraas (1889: 102, pl. 6, fig. 15). Designated lectotype by Hellrung (2003: 115).

Type locality and horizon: An alum mine in Gaildorf, Hohenlohe region, Baden-Württemberg, Germany. The horizon is the Lettenkeuper (‘Lettenkohle’ of earlier literature), which is Ladinian (upper Middle Triassic) in age ( Deutsche Stratigraphische Kommission, 2002). In the earlier literature, the mined layer at Gaildorf was variously referred to as the ‘Alaunschiefer’ or ‘Vitriolschiefer’ (e.g. von Meyer & Plieninger, 1844; Fraas, 1889), but the precise stratigraphic position of the fossiliferous horizon within the Lettenkeuper sequence at Gaildorf has been the subject of much debate (see Moser & Schoch, 2007, for a summary of the arguments).

Referred material: SMNS 13331, a partial skull and anterior postcranium described and figured by von Huene (1922: 418, figs 26, 28); scrappy remains reported by Schmidt (1931), Oertle (1936) and Müller (1966); NHMS-WT 648, 649, 650, 871 and ‘Sammlung Witter’ Nr. 79, disarticulated partial skeletons reported and in part figured by Werneburg & Witter (2005). (Note that ‘Sammlung Witter’ represents a private collection.) Additional fragmentary material has been referred to Plagiosuchus pustuliferus by Hellrung (2003), but none of this was figured or described.

Geographical and stratigraphic range: Plagiosuchus pustuliferus remains are known from a number of localities in Baden-Württemberg and Thuringia, including specimens documented from postcranial remains only ( R. Damiani, R. Schoch, H. Hellrung, R. Werneburg, S. Gastou, unpubl. data). Stratigraphically, the species ranges from the Grenzbonebed (Oberer Muschelkalk, Ladinian) to the overlying Lettenkeuper, where it has been recorded in three horizons (Vitriolschiefer, Sandige Pflanzenschiefer, Untere Graue Mergel) ( Hellrung, 2003). The fauna and stratigraphy of the Lettenkeuper sequence is described in Schoch (1999, 2002a) for the localities in Baden-Württemberg , and in Werneburg & Witter (2005) for the localities in Thuringia.

Emended diagnosis: The cranium of Plagiosuchus pustuliferus can be distinguished from all other plagiosaurids by a suite of autapomorphies, as follows: (1) orbits greatly expanded posteriorly, forming orbitotemporal fenestrae; (2) prefrontal, postfrontal and, possibly, postorbital absent; (3) maxillary tooth row short; (4) maxillary teeth tiny; (5) jugal massive, forming major part of the skull margin; (6) interpterygoid vacuities large, rectangular in outline; (7) subtemporal vacuities long and narrow; (8) palatal ramus of pterygoid long and narrow; (9) massively elongated post-glenoid area of mandible; (10) coronoid series reduced to posterior coronoid only; (11) angular contacts posterior coronoid labially, precluding a dentary–surangular contact; (12) dentary short but adductor fossa long (correlating with the short maxilla and long subtemporal vacuities, respectively).