Weissia, BRANCO, 1887

Schoch, Rainer R. & Witzmann, Florian, 2009, Osteology and relationships of the temnospondyl genus Sclerocephalus, Zoological Journal of the Linnean Society 157 (1), pp. 135-168 : 137-141

WEISSIA BRANCO, 1887

KLAUSWALDIA KRÄTSCHMER & RESCH, 2005

Diagnosis: Autapomorphies, as contrasted with eryopids (sensu Boy, 1990) and basal stereospondylomorphs ( Figs 3A–C , 4 ).

1. Supratemporal slender and elongated (length/ width: 1.7–2.4).

2. Lacrimal narrower than alary process of maxilla.

3. Preorbital region less than twice the length of the posterior skull table (snout length/length of posterior skull table: 1.6–1.8).

4. Palatine and ectopterygoid bearing a continuous row (or several rows) of teeth, combined with a pair of tusks.

5. Interclavicle wide and posteriorly triangular (width/length: 0.6–0.65).

Status of Sclerocephalidae: The higher-rank (familylevel) name Actinodontidae Lydekker, 1885 was formerly applied to Sclerocephalus (e.g. Boy, 1988; Schoch & Milner, 2000). This name was derived from a taxon from the Permian of France, Onchiodon (Actinodon) frossardi ( Gaudry, 1866) , which Werneburg & Steyer (1999) argued to be closely related to the eryopid Onchiodon labyrinthicus Geinitz, 1861 . Following these authors, Actinodontidae Lydekker, 1885 would be a junior synonym of Eryopidae Cope, 1882 . Boy (1988) placed Sclerocephalus in the Actinodontidae , because Onchiodon (Actinodon) frossardi was at that time considered to be a close relative of S. haeuseri and was possibly synonymous. However, there is a broad consensus that Sclerocephalus does not fall into the Eryopidae , but is more closely related to the Permian stereospondylomorph Archegosaurus ( Boy, 1988, 1993, 1996; Yates & Warren, 2000; Schoch & Milner, 2000; Witzmann & Schoch, 2006a; present analysis). An available higher-rank taxon name is Sclerocephalidae Abel, 1909. However, at this stage it is unclear whether all four Sclerocephalus species fall into one clade, or form a grade with respect to the higher Stereospondylomorpha (see analysis and discussion below).

TYPE SPECIES

Figures

Figure 3. Original material of large adult specimens of Sclerocephalus haeuseri: A, skull of POL-F 002, L–O 10 (dorsal view); B, skull of GPIM-N 1190, L–O 8 (dorsal view, with lateral lines); C, skull of GPIM-N 1203, L–O 9 (dorsal view); D, tail skeleton with skin preservation and bony scales (SMNS 90055); E, forearm and manus (SMNS 90055); F, complete skeleton (SMNS 90055).

Figure 4. Skull reconstruction of Sclerocephalus haeuseri: A, dorsal view; B, ventral view; C, lateral view; D, occipital view; E, mandible in lingual view; F, mandible in labial view. Based on BSPHM-1981 I 99, SMNS 81791, and other specimens from the Jeckenbach Black Shale (L–O 6). Please refer to the text for the list of abbreviations.