Brachiopoda Duméril, 1806

Stott, Christopher A. & Jin, Jisuo, 2007, The earliest known Kinnella, an orthide brachiopod from the Upper Ordovician of Manitoulin Island, Ontario, Canada, Acta Palaeontologica Polonica 52 (3), pp. 535-546 : 539

Phylum Brachiopoda Duméril, 1806 Order Orthida Schuchert and Cooper, 1932 Superfamily Enteletoidea Waagen, 1884 Family Draboviidae Havlíček, 1950 Genus Kinnella Bergström, 1968

Type species: Hirnantia? kielanae Temple, 1965 , Dalmanitina Beds (Hirnantian), Holy Cross Mountains, Poland.

Discussion.—In external morphology, Kinnella has a certain degree of resemblance to the Late Ordovician Fascifera Ulrich and Cooper, 1942 , especially in its small, ventribiconvex shell, multicostellae, and a high, weakly curved, apsacline ventral interarea. Internally, however, the North American Fascifera has high, basomedially inclined brachiophore plates, which are basolaterally divergent in Kinnella . The delthyrium is high and trapezoidal in Kinnella but sharply triangular in Fascifera . The Manitoulin Island form of Kinnella described in this paper has all the diagnostic characters of Kinnella and is the only species currently known from pre−Hirnantian strata. In typical Kinnella , the ventral interarea tends to be strongly apsacline approaching catacline ( Bergström 1968; Rong 1984). Among the shells described as K. kielanae by Lespérance and Sheehan (1976) from Percé, Québec, some ventral valves have an apsacline ventral interarea forming an angle of 60° with the commissural plane; these do not approach a catacline orientation. Consequently it is important to note that even within the type species the orientation of the ventral interarea appears to be variable. As will be discussed below, there is also considerable ontogenetic variation in the tilting angle in Kinnella ventral valves from Manitoulin Island.