Eichstaettisaurus schroederi, (BROILI, 1938)

EICHSTAETTISAURUS SCHROEDERI ( BROILI, 1938)

Ardeosaurus? schr oderi € Broili, 1938: p. 97 , taf. 1 – 4 Broilisaurus schroederi Hoffstetter, 1953: p. 347 ; fig. 1A

Eichstaettisaurus schroederi Kuhn, 1958: p. 380 Eichstaettisaurus digitatellus Cocude-Michel, 1963: p. 150 , plate XXX, B

Eichstaettisaurus schroederi Hoffstetter, 1964: p. 287 ; plate 6 (fig. 5)

Holotype: BSPG 1937 I 1 a & b ( Fig. 1 View Figure 1 ), complete skeleton preserved in dorsal view and counterpart.

Locality and horizon: Solnhofen Limestone, Tithonian, Late Jurassic; Wintershof wei Eichst€ att, Germany.

Revised diagnosis: Eichstaettisaurus schroederi can be distinguished from Eichstaettisaurus gouldi in having the parietals paired; frontal subolfactory processes in contact medially; a frontoparietal suture smooth and slightly convex anteriorly; frontal and parietals of equal width at their suture and in contact laterally; straight and laterally projecting caudal transverse processes; autotomy septa at the level of the fifth caudal.

Remarks: Eichstaettisaurus schroederi differs from both Ardeosaurus species in having strongly laterally emarginated paired parietals; frontals totally fused in dorsal aspect; parietals with shorter supratemporal processes; frontoparietal suture slightly convex anteriorly; postorbital and postfrontal as separate elements; seven cervical vertebrae; and more than 30 presacral vertebrae. Eichstaettisaurus schroederi further differs from A. digitatellus in having a wide posterior parietal margin between supratemporal processes. Eichstaettisaurus schroederi further differs from A. brevipes in the absence of skull roof ornamentation and cephalic osteoderms, as well as a pedal phalangeal formula of 2-3-4-5-4. The difference in the degree of frontal interorbital constriction between E. schroederi and E. gouldi used by Evans, Raia & Barbera (2004) to differentiate these two species does not correspond to our measurements. The former authors’ ratio for the frontal interorbital/frontoparietal widths for E. gouldi (0.2) seems to be accurate based on our analysis of the published picture of the holotype. However, our personal measurement of E. schroederi indicates that the interorbital/frontoparietal ratio is 0.25, not 0.32 as reported by Evans et al. (2004) – see Table 1 below, as well as the Material and Methods section above. See also Appendix 2 for phylogenetic autapomorphies for E. schroederi from the analysis performed herein.

EICHSTAETTISAURUS GOULDI EVANS, RAJA & BARBERA, 2004

Holotype: MPN 19457 , articulated partial skeleton preserved in ventral view.

Locality and horizon: La Cavere outcrop, Pietraroia, Mount Matese, southern Italy. The horizon is Albian (Upper Plattenkalk), Early Cretaceous.

Revised diagnosis: Eichstaettisaurus gouldi can be distinguished from E. schroederi in having the parietals fused; subolfactory processes of frontals well developed, but not in contact medially; frontoparietal suture with the parietal slightly concave medially, receiving a posterior convexity of the frontal; the frontal being slightly wider than the parietals at their suture; at least one posteriorly orientated anterior caudal transverse process; autotomy septa, if present, begin beyond the level of the sixth caudal.

Remarks: Eichstaettisaurus gouldi shares with E. schroederi a depressed skull; short and blunt snout; absence of lacrimals; paired premaxillae; postorbital and postfrontal as separate elements; frontals fused; frontals widen anteriorly; frontal interorbital/frontoparietal width ratio between 0.2 and 0.3.