Monodechenella morganensis ( Mitchell 1918 )

Vanderlaan, Tegan A. & Ebach, Malte C., 2015, A review of the Carboniferous and Permian trilobites of Australia, Zootaxa 3926 (1), pp. 1-56 : 22

Monodechenella morganensis ( Mitchell 1918)

1918 Phillipsia morganensis Mitchell ; p. 471, pl. 49, figs. 11–12, pl. 51, fig. 1. 1969 Cyrtoproetus morganensis ; Hahn & Hahn, p. 56.

1984 Conophillipsia morganensis ; Engel & Morris, p. 47, figs. 14, 15A-C.

Lectotype. QGSF1000 (internal mould of cranidium).

Locality. Type—QGS L3004.

Emended diagnosis. Glabella touches anterior border furrow; glabellar length slightly longer than width, gently convex. Pygidium parabolic in outline, border convex; axis slopes posteriorly; 12+ axial rings, ring furrows straight or gently curving posteriorly; 9+ pleural ribs.

Remarks. Monodechenella morganensis was originally described from a single specimen, QGSF1000 ( Engel & Morris 1984). A number of other specimens were questionably assigned to M.? morganensis given their similarity to the type specimen of M. morganensis , but they possess more axial rings and pleural ribs ( Engel & Morris 1984). We consider these specimens as belonging to M. morganensis due to the identical cephalic features. Differentiation of M. morganensis from other Australian Monodechenella species is based on the extremely flat nature of the cephalon, plus much less defined pygidial axis furrows.