Tethyoceramus ( Sornay, 1980 )

Landman, Neil H., Plint, A. Guy & Walaszczyk, Ireneusz, 2017, Allostratigraphy And Biostratigraphy Of The Upper Cretaceous (Coniacian-Santonian) Western Canada Foreland Basin, Bulletin of the American Museum of Natural History 2017 (414), pp. 1-173 : 69

Tethyoceramus ( Sornay, 1980)

TYPE SPECIES: Inoceramus (Tethyoceramus) basseae Sornay (1980 : pl. 1, figs. 1, 4, 6; pl. 2, figs. 1–3) by original designation.

DIAGNOSIS AND DISCUSSION ON THE GENUS: See Walaszczyk and Wood (1998).

Tethyoceramus sp.

Figure 8

MATERIAL: Six specimens in total. Single unnumbered specimen from Mill Creek , from 76.6 m ; 4 specimens from Bighorn Dam: TMP 2016.041.0395 and TMP 2016.041.0391 from 8.5 m; TMP 2016.041.0398 from 10.5 m; and TMP 2016.041.0400 from 41.5 m. Single specimen from Highwood River , TMP 2016.041.0139 .

REMARKS: The genus is relatively rare in the studied material, similar to the equivalent succession of the U.S. Western Interior ( Walaszczyk and Cobban, 2000). Most of the specimens are poorly preserved, incomplete single valves. Two left valves of specimen TMP 2016.041.0395 (fig. 8) resemble Tethyoceramus alpinus (Heinz) (the smaller specimen) and Tethyoceramus ernsti (Heinz) (the larger one). To the latter species may also be referred the huge specimen from Highwood River (TMP 2016.041.0139). TMP 2016.041.0400 (not illustrated) is referred herein to Tethyoceramus wandereri (Andert) , based on its very slender form and strong inflation.

OCCURRENCE: The genus is known from the mid lower Coniacian in Europe and in the American Western Interior (see Walaszczyk and Wood, 1998; Walaszczyk and Cobban, 2000), and is well represented in Madagascar, where it apparently starts at the topmost Turonian and ranges through most of the lower Coniacian ( Sornay, 1980; Walaszczyk et al., 2004, 2014a).

Figures

FIG. 8. Tethyoceramus sp., TMP 2016.041.0395 (two left valves), Wapiabi Formation, Bighorn Dam, 8.5 m: A, D, smaller specimen; A, lateral view; D, anterior view. B, C, larger specimen; B, anterior view, C, lateral view. All photographs are ×1.