Tuleaspis, E.B & Adrain & Karim, 2018

E. B, Neo, Adrain, Jonathan M. & Karim, Talia S., 2018, The pliomerid trilobite Ibexaspis and related new genera, with species from the Early Ordovician (Floian; Tulean, Blackhillsian) of the Great Basin, western USA, Zootaxa 4525 (1), pp. 1-152 : 33

Tuleaspis n. gen.

Type species. Tuleaspis jeneki n. sp., from the Fillmore Formation (Tulean, low Protopliomerella contracta Zone ), southern Confusion Range, Ibex area, Millard County, western Utah, USA.

Other species. Tuleaspis n. sp. A, Fillmore Formation, western Utah and Garden City Formation, southeastern Idaho (both Tulean; low Psalikilopsis cuspidicauda Zone ); Tuleaspis ? n. sp. B, Fillmore Formation (Tulean; low Protopliomerella contracta Zone ), western Utah.

Etymology. From the Tule Valley, and Greek aspis, shield. Gender is feminine.

Diagnosis. Diagnostic characters are not present in the cladistic analysis, because they would be represented as autapomorphies of T. jeneki . Members of Tuleaspis possess a long, broad, low-vaulted (tr., sag.) glabella with straight sides and a broadly, evenly bowed anterior margin; palpebral lobes lacking palpebro-ocular ridge and situated with broadest part opposite L2; hypostome with long posterior border of even length (not tapered and pointed medially and without marginal spines); and coarse tuberculate sculpture, particularly along axial furrows and on pygidium, with some small spiny tubercles at corners of LO and inner margin of posterior border.

Discussion. Other characteristics which set Tuleaspis apart from the other members of the Ibexaspis group are mainly plesiomorphic, and shared with species of Hintzeia or plesiomorphic species of Panisaspis: large, evenly shaped glabellar lobes; a broad, subtriangular librigenal field; a pygidium with a wide axis and posteriorly swept pleurae.