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Onniella kalvoya
Taxonomy
Onniella kalvoya was named by Cocks (1982). Its type specimen is PMO 104.021 (internal mould and external counterpart of a brachial valve) and is a 3D body fossil. Its type locality is Kalvøya, 5a, SP 25, which is in a Katian marine shale in the Husbergøya Formation of Norway.
Sister species lacking formal opinion data
Synonymy list
| Year | Name and author |
|---|---|
| 1982 | Onniella kalvoya Cocks pp. 762 - 763 figs. Plate 79, figs. 13, 14, 17, 18; Plate 80, figs. 1-5 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Onniella kalvoya Cocks 1982
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| L. R. M. Cocks 1982 | Exterior. Shells with subcircular outline; gently convex pedicle valve without incurved umbo; convex brachial valve with gentle sulcus. Relatively small apsacline pedicle valve interarea, narrow open delthyrium, with apex angle about 40°. Small anacline brachial valve interarea, approximately half valve width; open notothyrium partly filled with posterior of cardinalia. Primary ornament of relatively fine, even costellae (approx. 5 per mm at 3 mm anteriorly) with new ribs arising by branching; secondary ornament of concentric filae (14-16 per mm throughout valve length) more accentuated in rib troughs and rarely crossing rib crests.
Pedicle valve interior. Strong teeth supported by short stubby dental plates which merge anteriorly quickly with the valve floor; small crural fossettes present. Muscle field relatively small, extending for average of 34% valve length in five specimens, bilobed, adductor scars poorly differentiated (PI. 79, fig. 17). Vascular markings usually obscure, but pair of thick vascula media diverge anteriorly from diductor scars in some specimens. Brachial valve interior. Cardinal process relatively small, bilobed posteriorly, and continuing anteriorly in a thin shaft which merges further anteriorly with a low but distinct myophragm. Thick, stubby brachiophores which merge posterolaterally with subsidiary fulcral plates to give well-defined sockets, which are also bounded anterolaterally by thin socket plates. Tops of brachiophores diverging anteriorly at about 70°. Well-defined adductor area extending anteriorly for 50-60% of valve length; anterior scars longer and wider than posterior scars (PI. 79, fig. 13). |