DIELASMATINAE Schuchert, 1913

MACFARLAN, DONALD ALEXANDER BANKIER, 2023, Otapirian (Rhaetian) Terebratulida (Brachiopoda) of Zealandia, Zootaxa 5374 (1), pp. 1-34 : 6

Subfamily DIELASMATINAE Schuchert, 1913

The cosmopolitan genus Dielasma King 1859 has long been recorded as part of the New Zealand Triassic fauna. Trechmann (1918) described D. zealandica and listed but did not figure D. cf. himalayana Bittner 1899 . Wilckens (1927) did illustrate this species and Marwick (1953) suggested that more than one species may be present. Both species are from the Kaihikuan shellbed at Caroline Cutting, Southland. More recently Dagys (1959) suggested that Dielasma hungaricum and D. zealandicum could be included in his new genus Adygella .

Begg (1981) records one species of Dielasmatinae from the Malakovian - Etalian (Anisian) of Southland, and a different species from the Oretian (late Carnian - Norian; Cooper et al. 2004). The Malakovian - Etalian species is biconvex. The Oretian species is sulcate but is not figured. Other undescribed species are present in the Late Triassic. The entire group in Zealandia requires revision.

More recent work ( Stelhi 1965, Jin et al. 2006) regard Dielasma as a cosmopolitan late Paleozoic genus but do not recognize its presence in the Triassic. Feldman (2017) regarded Tunethyris Calzada et al. 1994 as a homeomorph of Dielasma and described Tunethyris blodgetti from the Middle Triassic of Southern Israel. Tunethyris is biconvex and has little resemblance to the two species described here.