Australokaskia Engel & Morris 1994

Vanderlaan, Tegan A. & Ebach, Malte C., 2015, A review of the Carboniferous and Permian trilobites of Australia, Zootaxa 3926 (1), pp. 1-56 : 25-26

Genus Australokaskia Engel & Morris 1994

1994 Australokaskia Engel & Morris ; p. 82–83. 1995 Australokaskia ; Engel & Morris, p. 194.

Type species. Australokaskia (Australokaskia) corrugata Engel & Morris 1994 .

Emended diagnosis. Cephalic margin with up to 10 terrace ridges; glabella steep, constricted at γ, rather flat to strongly convex; eyes large. Pygidium with up to 12 axial rings, eight pleural ribs; wide border; ornament of concentric ridges.

Remarks. Engel & Morris (1994; 1995) described a large number of specimens from the Viséan of Australia as a new genus, Australokaskia . The genus is similar to both Witryides Hahn & Brauckmann 1986 and Kaskia Weller 1936 (Engel & Morris 1994) . Australokaskia is distinct in that it has a convex cranidium, up to 10 terrace ridges on a distinct cephalic border, a strongly convex glabella that expands anteriorly and a pygidium with a wide border.

The genus was originally divided into three subgenera, Australokaskia (Australokaskia) , Australokaskia (Longilobus) and Australokaskia (Planilobus) , none of which are retained herein. The subgenera were based on differences in the shape of the basal lobes (L1), and their anterior position relative to γ (Engel & Morris 1994). The diagnoses for Australokaskia (Longilobus) Engel & Morris 1995 and Australokaskia (Planilobus) Engel & Morris 1995 include long (exsag.) basal lobes, almost extending to γ (Engel & Morris 1995, pp. 194, 199), plus the moderately inflated basal lobes in A. (Longilobus) compared with the flat basal lobes in A. (Planilobus). L1 convexity differs in each of the diagnoses, but examination of the specimens assigned to both A. ( Australokaskia ) and A. (Longilobus) show no obvious difference in either length or relief of this feature. Hence, these subgenera have been provisionally synonymised within Australokaskia pending discovery of new material.

Species included. Australokaskia arduennensis (Hahn & Hahn 1968) , Australokaskia corrugata Engel & Morris 1994 , Australokaskia coulteri Engel & Morris 1994 , Australokaskia collina Engel & Morris 1994 , Australokaskia similis Engel & Morris 1995 , Australokaskia convexicaudata (Mitchell 1918) , Australokaskia noorooensis Engel & Morris 1995 , Australokaskia constricta Engel & Morris 1995 , Australokaskia soldevilai (Hahn et al. 1996)

Age and distribution. Upper Tournaisian to Viséan, in Australia, Belgium and Spain (Engel & Morris 1994; 1995; Hahn et al. 1996).