Paratypothorax andressorum Long & Ballew, 1985

Holotype.

SMNS 5721, postcranial elements of a single large individual comprising 22 left paramedian osteoderms, 15 right paramedian osteoderms (Fig. 17 B), 11 lateral osteoderms, an ischium, and a tibia. Long and Ballew (1985) identified a left dorsal paramedian osteoderm from this specimen as the holotype, but this ignores the fact that this element is part of a more complete set of skeletal elements.

Type locality.

Former quarry at Heslacher Wand, Stuttgart-Heslach, Baden-Württemberg.

Type horizon.

Lower Stubensandstein (S 1), Löwenstein Formation, Middle Keuper Subgroup. Age: Late Triassic (Norian: Lacian).

Referred material (from Germany only).

Parker (2016) provides a list of specimens. We add the following material: SMNS 19003, complete articulated skeleton including skull (Fig. 17 C). Body length: 2.12 m. Lower Stubensandstein (S 1), Schlipf Quarry at Köchersberg, Murrhardt, Baden-Württemberg (Figs 10 C, 11 C). SMNS 51437, an osteoderm from the Lower Stubensandstein (S 1) of the Busch quarry, Gerlingen. SMNS 59750 (cast of unnumbered original in Tu ̈ bingen), a lateral osteoderm from a quarry near Kayh, Baden-Württemberg.

Diagnosis.

Distinguished by the following autapomorphies: deep notch between premaxilla and maxilla; supratemporal fenestra triangular and with rounded edges; nuchal osteoderms narrow transversely and oval, much smaller than those of first paramedian dorsal row; and paramedian osteoderms very wide transversely (Schoch and Desojo 2016).

Comments.

The osteoderms of SMNS 5721 were long interpreted as parts of the dorsal dermal armor of phytosaurs, specifically Nicrosaurus kapffi (Meyer 1861; Westphal 1963). Long and Ballew (1985) first recognized their stagonolepidid affinities. These authors also identified various osteoderms from the Upper Triassic (Norian) Cooper Canyon Formation of Texas as Paratypothorax sp. Based on the close similarities in cranial structure, Schoch and Desojo (2016) suggested that Paratypothorax andressorum possibly represents the fully grown adult ontogenetic stage of Aetosaurus ferratus. However, due to a considerable gap between the known sizes and current lack of synapomorphies, this intriguing idea remains to be tested by future discoveries.

References.

Meyer (1861), Westphal (1963), Long and Ballew (1985), Parker (2016), Schoch and Desojo (2016).