Similothecidae Malinky, 1988

Malinky, John M. & Skovsted, Christian B., 2004, Hyoliths and small shelly fossils from the Lower Cambrian of North-East Greenland, Acta Palaeontologica Polonica 49 (4), pp. 551-578 : 553

Family Similothecidae Malinky, 1988 Genus Similotheca Malinky, 1988 emended

Type species: Hyolithes similis Walcott, 1890 , Lower Cambrian , Newfoundland .

Diagnosis.—Similothecid having flattened venter, grading into keel−like lateral edges, which in turn pass into dorsal flanks, which are convex near the lateral edges but become concave close to the middle of the dorsum.

Remarks.—This genus was based on material described by Walcott (1890a, b) from the Brigus Formation (formerly Smith Point Formation; see Landing and Benus 1988). Diagnostic traits include the keel−like dorsal ridge, concavo−convex flanks of the dorsum and longitudinal elements of sculpture on the dorsum. The concept of Similotheca is broadened herein to encompass forms with a reduced concavity adjacent to the dorsal ridge and less steeply dipping dorsal flanks.

Stratigraphic range and distribution.—Lower Cambrian; southeastern Newfoundland and Greenland.