Tiramnia Grunt, 1977

Poletaev, Vladyslav, 2024, New and revised taxa of Carboniferous spiriferides (Brachiopoda, Spiriferida) from the Donets Basin (Ukraine) and South Urals (Russia), European Journal of Taxonomy 968, pp. 132-155 : 136

Genus Tiramnia Grunt, 1977

Type species

Martinia uralica Chernyshev, 1902 ; original designation.

Diagnosis

Shells small to medium-sized, brachythyrid outlines, without plates or septa in either valve; fold and sulcus weakly or moderately developed; furrow in sulcus is very weak or absent. Surface smooth or with the weak, short ribs on anterior edge. Muscle field of ventral valve comparatively large, lanceolate; radial vascular imprints ramiform; axial mantle canal (vascula media) singular.

Included Pennsylvanian species

Arctic Russia, the northern Ural ( Chernyshev 1902; Grunt 1977): Tiramnia uralica ( Chernyshev, 1902) , T. semiglobosa ( Chernyshev, 1902) Permian, Cisuralian ; T. tschaikensis Grunt, 1977 ; upper Pennsylvanian, Cape Chaika.

Arctic Canada and Southeastern Alaska ( Carter & Poletaev 1998): Tiramnia waltery Poletaev, 1998 and T. grunti Poletaev, 1998 ; Pennsylvanian.

Greenland ( Grunt 1977): Tiramnia greenlandica Grunt, 1977 ; Permian.

China ( Chao 1929): Tiramnia changchiacouensis Chao, 1929 ; Pennsylvanian.

Ukraine (this paper) Tiramnia davidi sp. nov., Lower Pennsylvanian.

Remarks

Tiramnia Grunt, 1977 differs from Martinia M’Coy, 1844 by the presence of a ramified vascular system; Tiramnia differs from Jilinmartinia Li & Gu, 1980 by having single (connected) vascula media rather than paired vascula developed in the ventral interior of the latter. Tiramnia differs from the somewhat similar Postamartinia Wang & Yang, 1993 by having round, elongated, but not transverse shells, by the absence of low ribs on the flanks, and by a much shorter tongue of sulcus.