Brachymetopus (Brachymetopus) regularis Engel & Morris 1992

Vanderlaan, Tegan A. & Ebach, Malte C., 2015, A review of the Carboniferous and Permian trilobites of Australia, Zootaxa 3926 (1), pp. 1-56 : 14

Brachymetopus (Brachymetopus) regularis Engel & Morris 1992

Fig. 4.12

1992 Brachymetopus (Brachymetopus) maccoyi regularis Engel & Morris ; p. 75–77, pl. 1, figs. 1–9, text-figs. 1, 2.

Holotype. AMF84292 (external mould of cephalon).

Paratype material. From NU L39: AMF84293 (external cephalon), AMF84294 (external cephalon), AMF84295 (external cephalon), AMF84296 (external cephalon), AMF84297 (external cephalon), AMF84298 (external cephalon), AMF84299 (external cephalon), AMF84300 (external cephalon), AMF84301 (external cephalon), AMF84302 (external cephalon), AMF84303 (external cephalon), AMF84304 (external cephalon), AMF84305a–c (2 internal cephala and external pygidium), AMF84306 (internal cephalon), AMF84307 (internal cephalon), AMF84308 (external pygidium), AMF84309 (external pygidium), AMF84310 (external pygidium), AMF84311 (external pygidium), AMF84312 (external pygidium), AMF84313 (internal pygidium), AMF84314 (internal pygidium), AMF84315 (internal pygidium). From AGS L3004: QGSF 1007(3) (partial external pygidium), QGSF 1007(4) (2 partial cranidia), QGSF 1007(5) (partial internal preglabellar field).

Locality. Type—NU L39. Other—QGS L3004.

Emended diagnosis. Cephalon rounded anteriorly; glabella rounded anteriorly, about half the cephalic length; preglabellar field sloping at 35–40°; smooth furrow inside cephalic border; four large nodules around the anterior of the glabella; eyes at least half glabellar length, up to three quarters; nodes around inner edge of cephalic border with parallel row of nodes around outer edge. Pygidium with 11–12 axial rings; 7 pleural ribs; marginal spines present; laterally spinose pygidium; nodes on the pygidial axis; posterior ribs not incurved.

Remarks. The above diagnosis has been emended from Engel & Morris (1992), with changes including the size of the eyes and ornament on both the cephalon and pygidium. Brachymetopus (Brachymetopus) regularis can be regarded as a separate species from Brachymetopus (Brachymetopus) maccoyi due to differences in cephalic ornament (large nodules around the anterior of the glabella and fewer nodules on the genae), large nodules on the pygidial axis, and the presence of spines on the pygidium.