Cricosaurus bambergensis, Sachs & Young & Abel & Mallison, 2021

Sachs, Sven, Young, Mark T., Abel, Pascal & Mallison, Heinrich, 2021, A new species of Cricosaurus (Thalattosuchia, Metriorhynchidae) based upon a remarkably well-preserved skeleton from the Upper Jurassic of Germany, Palaeontologia Electronica (a 24) 24 (2), pp. 1-28 : 23-24

Cricosaurus bambergensis Sachs et al., 2019

v* 2019 Cricosaurus bambergensis sp. nov. – Sachs et al., p. 1, figs.3-7, 9a.

Holotype. NKMB-P-Watt14/274: almost complete skeleton preserved in lithographic limestone ( Figures 9B , 10D ).

Type locality. Kalk- und Dolomitbruch der Andreas Schorr GmbH, Wattendorf, Bamberg district, Bavaria, Southern Germany.

Type horizon. Wattendorf Member, Torleite Formation. Aulacostephanus pseudomutabilis Tethys ammonite Zone, upper Kimmeridgian, Upper Jurassic.

Etymology. ‘Ring lizard from Bamberg’.

Geological range. Upper Jurassic. Aulacostephanus pseudomutabilis, Tethys ammonite Zone, upper Kimmeridgian.

Emended diagnosis. A member of Cricosaurus with the following unique combination of characters (proposed autapomorphic characters are indicated by an asterisk *): bicarinate dentition, lacking conspicuous enamel ornamentation; tooth crowns in the premaxilla, maxilla and dentary show distinct labiolingual compression (shared with C. albersdoerferi BMMS-BK 1-2, C. suevicus SMNS 9808 and C. elegans SNSB-BSPG AS I 504); the maxillary tooth row clearly continues posteriorly past the anterior-margin of the orbit (thalattosuchian symplesiomorphy); presence of pronounced reception pits on the lateral margins of the anterior and middle maxilla for dentary tooth crowns (shared with C. albersdoerferi BMMS-BK 1-2); palatines have a distinct midline ridge with paired depressions either side*; estimated to have approximately 50, or more, caudal vertebrae; morphology of the tail displacement unit: the distal-most three preflexural vertebrae have neural spines that are oriented strongly posteriorly, their posterior margin lies on top of the prezygapophyses of adjacent vertebra; however, these neural spines do not have the almost rod-like appearance (in lateral view) that C. suevicus (SMNS 9808) has; the three vertebrae anterior to them have a similar morphology, but the neural spines look more like a ‘regular’ neural spine, albeit strongly oriented posteriorly*.

Cricosaurus bambergensis retains the following four metriorhynchid tail fluke symplesiomorphies (unlike C. albersdoerferi BMMS-BK 1-2 and C. suevicus SMNS 9808, GPIT-PV-31381): 1) the distal-most preflexural caudal vertebra has a rod-like hemapophysis; 2) the proximal-most five or six flexural vertebrae have anteriorly oriented neural spines, but not strongly oriented anteriorly; 3) the flexural hemapophyses contact one another along their anterior-posterior margins; and 4) the distal-most post-flexural hemapophysis return to a ‘rod-like’ morphology (modified from Sachs et al., 2019).

Figures

FIGURE 9. Comparison of crania of Late Jurassic Cricosaurus specimens from southern Germany. (A) BMMS-BK 1-2, holotype of Cricosaurus albersdoerferi sp. nov.; (B) NKMB-P-Watt14/274, holotype of Cricosaurus bambergensis; (C) SNSB-BSPG AS I 504, holotype of Cricosaurus elegans; (D) SMNS 9808, lectotype of Cricosaurus suevicus; (E) GPIT-PV-31381, referred specimen of Cricosaurus suevicus and (F) SMNS 7322, referred specimen of Cricosaurus suevicus. Scale bars equal 50 mm.

FIGURE 10. Comparison of tail bends of Late Jurassic Cricosaurus specimens from southern Germany. (A) BMMS-BK 1-2, holotype of Cricosaurus albersdoerferi sp. nov.; (B) SMNS 9808, lectotype of Cricosaurus suevicus; (C) GPIT-PV- 31381, referred specimen of Cricosaurus suevicus; (D) NKMB-P-Watt14/274, holotype of Cricosaurus bambergensis. No scale bars intended.