Ebiscothyris, Bitner & Cohen, 2015

Bitner, Maria Aleksandra & Cohen, Bernard L., 2015, Congruence and conflict: case studies of morphotaxonomy versus rDNA gene tree phylogeny among articulate brachiopods (Brachiopoda: Rhynchonelliformea), with description of a new genus, Zoological Journal of the Linnean Society 173 (2), pp. 486-504 : 494

GENUS EBISCOTHYRIS GEN. NOV.

Type species

Ebiscothyris bellonensis gen. et sp. nov.

Diagnosis

Medium-sized terebratulide; outline subpentagonal; surface smooth; anterior commissure strongly and broadly unisulcate; beak suberect; deltidial plates conjunct; foramen circular, of medium size; cardinal process distinct, semi-elliptical; crural processes blunt and directed ventrally; hinge plates narrow and triangular; loop short, with broad descending branches and broad, medially folded, transverse band.

Etymology

Referring to the cruise, EBISCO, during which the specimens were collected.

Remarks

The strongly unisulcate anterior commissure of Ebiscothyris gen. nov. differentiates it from other extant members of the Terebratulidae , which are commonly rectimarginate to weakly uniplicate. The only terebratulid genus with a similarly unisulcate anterior commissure is Kanakythyris Laurin, 1997 from around New Caledonia and the Norfolk Ridge, but Kanakythyris clearly differs from Ebiscothyris gen. nov. in beak and loop characters ( Laurin, 1997; Bitner, 2009). The parallel descending branches and broad medially folded transverse bands of the Ebiscothyris gen. nov. loop resembles those of the terebratulid genera Acrobrochus Cooper, 1983 , Erymnia Cooper, 1977 , Tichosina Cooper, 1977 , Dolichozygus Cooper, 1983 , and Dysedrosia Cooper, 1983 , but unlike these genera Ebiscothyris gen. nov. clearly differs in external morphology and lacks well-defined and distinctive crural bases ( Cooper, 1977; Cooper, 1983). Like Ebiscothyris gen. nov., some dyscolioids are deeply unisulcate (e.g. Abyssothyris Thomson, 1927 ), but their loop has very narrow descending branches and an anteriorly rounded transverse band ( Cooper, 1983; Laurin, 1997; Bitner, 2006; 2008; Lee, 2006), differing markedly from Ebiscothyris gen. nov., which has the broad, medially folded transverse band characteristic of Terebratulidae (Lee & Smirnova, 2006) . Overall, morphology of the shell and loop lead us to allocate Ebiscothyris gen. nov. to the Terebratulidae rather than to the Dyscoliidae .