Mystriosuchus steinbergeri, Butler & Jones & Buffetaut & Mandl & Scheyer & Schultz, 2019

MYSTRIOSUCHUS STEINBERGERI SP. NOV.

lsid:zoobank.org:act: 33CEDCFB-C9B0-4D5B-A25F- 4B6E2A49FA6C

‘ Mystriosuchus planirostris ’; Buffetaut, 1993: p. 42, fig. 4.

‘Phytosaur remains (possibly Mystriosuchus ) in the southern part of the Totes Gebirge’; Renesto & Paganoni, 1998: p. 119.

‘ Mystriosuchus specimens found in the Norian Dachsteinkalk’; Renesto & Lombardo, 1999: p. 136.

‘ Mystriosuchus from the Norian Dachsteinkalk of Austria’; Irmis et al., 2010: p. 42.

‘Dachsteinkalk-Formation… Mystriosuchus ’; Kimmig & Arp, 2010: p. 222.

‘Well-preserved material of Mystriosuchus … from the Dachsteinkalk of Austria’; Stocker & Butler, 2013: p. 102.

Etymology: The species is named for Sepp Steinberger, who discovered and helped collect the holotype and referred specimens.

Holotype: NHMW 1986 View Materials /0024/0001, partial skull, missing most of left side.

Paratype: NHMW 1986 View Materials /0024/0002, articulated mandibles (missing posterior end of right mandible), very likely representing the same individual as NHMW 1986 View Materials /0024/0001.

Referred specimens: NHMW 1986 View Materials /0024/0003, left ilium (recovered adjacent to NHMW 1986 View Materials /0024/0002 and possibly representing the same individual as the holotype and paratype) ; NHMW 1986 View Materials /0024/0004, paired anterior portion of articulated premaxillae ; NHMW 1986 View Materials /0024/0005 and NHMW 1986 View Materials /0024/00016, partial skull and probably associated mandibular remains ; NHMW 1986 View Materials /0024/0006a, b, partial skull (b) and probably associated mandibular remains (a) ; NHMW 1986 View Materials /0024/0007, nearly complete left humerus ; NHMW 1986 View Materials / 0024/0008, proximal end of left humerus ; NHMW 1986 View Materials /0024/0009, distal end of left humerus ; NHMW 1986 View Materials /0024/0010, left ulna ; NHMW 1986 View Materials /0024/00011, left ulna ; NHMW 1986 View Materials /0024/0012, complete right femur ; NHMW 1986 View Materials /0024/0013, proximal end of right femur ; NHMW 1986 View Materials /0024/0014, left tibia ; NHMW 1986 View Materials /0024/0015, osteoderm ; NHMW 1986 View Materials /0024/0018, fragment of shaft of tibia ; NHMW 1986 View Materials /0024/0019, fragment of distal end of femur ; NHMW 1986 View Materials /0024/0024, jaw fragment. Numerous additional unaccessioned fragments of cranial and postcranial remains are also present in the NHMW collections, but provide no useful anatomical details in additional to the accessioned specimens listed above.

Locality and horizon: 380 m SSE of the mountain Hochweiss , southern part of the Totes Gebirge mountain range , 7.1 km north of Tauplitz , Liezen district , Styria (Steiermark), central Austria. Coordinates : 47° 37′ 30″ N, 14° 00′ 40″ E. The locality has been added to the Paleobiology Database and is locality number 97845. Dachstein Limestone ( Dachsteinkalk ), Upper Triassic (middle Norian: Alaunian) GoogleMaps .

Differential diagnosis: Species of Mystriosuchus characterized by the following combination of characters: (1) ratio of length of preorbital region of skull to length of orbital + postorbital length estimated as not exceeding 3.3 (3.9–4.1 in M. planirostris ) and ratio of prenarial to narial + postnarial length not exceeding 1.8 (1.8–2.2 in M. westphali , 2.6 in M. planirostris ); (2) fewer than 40 teeth in upper jaws (41–50 in M. westphali , 48 in M. planirostris ); (3) premaxillary crest absent (crest present in M. westphali ); (4) dorsal margin of internarial bar and dorsal margin of premaxilla merge smoothly into one another (meet at an angle of nearly 90° to one another in M. planirostris ); (5) anterior part of external naris placed anterior to the antorbital fenestra (naris placed entirely dorsal to antorbital fenestra in M. westphali ); (6) anteroposterior length of the naris is less than that of the orbit (naris and orbit subequal in anteroposterior length in M. westphali ); (7) internarial bar not depressed ventrally relative to level of lateral narial rim and visible in lateral view along entire length (internarial bar depressed ventral to lateral narial rim and only visible in lateral view at its anterior end in M. planirostris and M. westphali ); (8) posterior rims of nares not distinctly raised into ‘volcano-like’ structure (‘volcano-like’ structure present in M. westphali ); (9) alveolar margin of maxilla straight to concave in lateral view (alveolar margin convex in lateral view in M. westphali ); (10) antorbital fenestra large (maximum dorsoventral height exceeds that of the orbit) and separated from the external naris by a distance equal to, or less than, the maximum dorsoventral height of the former (antorbital fenestra reduced in size and more broadly separated from the external naris in M. westphali and M. planirostris ); (11) antorbital fenestra expands in dorsoventral height towards its posterior end (antorbital fenestra oval and tapers posterodorsally in M. westphali and M. planirostris ); (12) broad, deep and sharply defined antorbital fossae present on the lacrimal and jugal posterior to the fenestra (fossae absent in M. westphali , variably developed and poorly defined in M. planirostris ); (13) jugal enters posterior rim of antorbital fenestra (excluded from rim by maxilla–lacrimal contact in M. westphali ); (14) descending process of the postorbital posteriorly expanded at its proximal end (entire process approximately consistent in thickness in M. westphali and M. planirostris ); (15) parietal– squamosal bar depressed approximately 25% of skull height below the posterior portion of the skull table (depressed>30% of skull height in M. planirostris ); (16) suborbital fenestra anteroposteriorly elongate and wide (reduced to small fenestra in M. westphali and M. planirostris ).