GENUS WELTNERIUM ZEVINA, 1978 B

FIGURES 1F, G, 3D, H, 7A–J, 8D, H, L, 12A–H

Type species

Scalpellum nymphocola Hoek, 1883, original designation of Zevina 1978b.

Diagnosis

Inframedian latus pentagonal, with subparallel lateral margins, somewhat taller than broad; umbo central, usually close to rostrolatus margin. Rostrum well developed, large trapezoidal to rectangular external surface, extending over full height of rostrolatera. Scutum markedly trapezoidal, scutal and tergal margins short, basal–occludent angle acute (60°), tergal– upper latus angle 120°. Pit for dwarf males deep, oval, transverse.

Synonyms

Ornatoscalpellum Zevina, 1978a, Tarasovium Zevina, 1978a (partim), and Anguloscalpellum Zevina, 1978b (partim).

Referred species

Scalpellum stroemii M. Sars, 1859, Scalpellum gibberum Aurivillius,1892, Scalpellum ornatum Gray, 1848, Scalpellum nymphocola Hoek, 1883, Scalpellum convexum Nilsson-Cantell, 1921, Scalpellum cornutum G.O. Sars, 1879, Scalpellum natalense Barnard, 1924, Scalpellum valvulifer Annandale, 1910, Scalpellum recurvirostrum Hoek, 1883, and Scalpellum angulare Nilsson-Cantell, 1930 .

Remarks

Weltnerium, as diagnosed here, is a monophyletic derived group characterized by a pentagonal inferior median latus with a low umbo, a tall, narrow rostrum with a large external surface, a markedly trapezoidal scutum, and a large transverse receptacle for dwarf males. Forms with subapical carinal umbones (‘ Ornatoscalpellum ’) and projecting carinolatera (some ‘ Tarasovium ’) fall into this category. It is not known from the fossil record.