A review of the Carboniferous and Permian trilobites of Australia Author Vanderlaan, Tegan A. Author Ebach, Malte C. text Zootaxa 2015 3926 1 1 56 journal article 10.11646/zootaxa.3926.1.1 93974765-12a0-4ee8-bea2-e6448e88d9bd 1175-5326 288002 342DDB94-4739-464B-AF67-4B17C6EE35D7 Monodechenella subtriangularis ( Engel & Morris 1984 ) 1847 Phillipsia cf. gemmulifera McCoy, p. 231. 1984 Conophillipsia subtriangularis Engel & Morris; p. 39–41, figs. 10–11. Holotype . AMF80518 (internal mould of cranidium). Paratype material. From NU L353: AMF80519 (internal pygidium), AMF80520 (external pygidium), AMF80522 (external pygidium). From MUM : AMF80521 (internal pygidium). From DV: CSMF 10586a/b (internal/external pygidium). Locality. Type—NU L353. Others—DV, MUM . Emended diagnosis. Glabella tapers anteriorly; slightly incised at γ; S1 very distinct, S2 less distinct; strongly convex. Pygidium triangular in outline; concave pygidial border; 12+ pleural ribs; 14+ axial rings. Remarks. There are few specimens of Monodechenella subtriangularis available for study, but they seem to closely resemble M. speciosa . Some of the distinguishing features between the two species noted by Engel & Morris (1984) appear to be dubious. For instance, there are a greater number of pygidiual rings and ribs in M. subtriangularis . The other distinguishing characters between M. subtriangularis and M. speciosa seem more obvious, that is the densely nodose ornament of M. speciosa , the different convexities of the pygidial borders and the more convex axis of the glabella in M. subtriangularis . We consider these differences sufficient to warrant the separation of these species.