Zenaspis Lankester, 1870 sensu Janvier 1985b

Voichyshyn, Victor, 2006, New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine, Acta Palaeontologica Polonica 51 (1), pp. 131-142 : 133

Genus Zenaspis Lankester, 1870 sensu Janvier 1985b

Type species: Cephalaspis salweyi Egerton, 1857 , Lower Devonian of Great Britain .

Diagnosis.— Zenaspididae of moderate size (L = 90–130 mm). The width of the shield is greater than its length (L/S = 0.6–0.7). The prepineal part of the shield is shorter than the postpineal one (B/C = 0.8–0.9). The cornual processes are comparatively short. The abdominal part of the shield is short with a massive median dorsal crest. The hypophysial division of the nasohypophysial opening is somewhat larger than the nasal division. The orbital openings are small (S/Os = 32–42) with a short distance between them (Omin/Os = 2.5–3.3). The median dorsal field is comparatively broad (index S/Sd is 9–11). The lateral fields are considerably dilatated (widened) in their posterior parts and extend into the base of the cornual processes. The distance between the posterior part of the lateral fields and the anterior margin of the pectoral sinus is approximately the same as to the lateral margins of the shield. The ornamentation consists of single large tubercles.

Species included.—Perhaps, Z. metopias ( Wängsjö, 1952) from the Lower Devonian of Spitsbergen; Z. dzieduszyckii sp. nov. and Z. podolica ( Balabai, 1962) , both from the Lower Devonian of Podolia.

Occurence.—Lower Devonian of Great Britain, Spitsbergen (?), Podolia.