Monodechenella speciosa ( Engel & Morris 1984 )

Vanderlaan, Tegan A. & Ebach, Malte C., 2015, A review of the Carboniferous and Permian trilobites of Australia, Zootaxa 3926 (1), pp. 1-56 : 20

Monodechenella speciosa ( Engel & Morris 1984)

1984 Conophillipsia speciosa Engel & Morris; p. 41–47, figs. 12–13.

Holotype. AMF80538 (internal mould of cranidium, partial external mould of glabella and anterior border).

Paratype material. From NU L427: AMF80523 (internal pygidium), AMF80524 (internal pygidium). From NU L894: AMF80525a/b (external/internal pygidium), AMF80526 (external pygidium), AMF80527 (external pygidium), AMF80528 (partial external pygidium), AMF80529 (external pygidium), AMF80530 (external librigena), AMF80531a/b (external/internal pygidium), AMF80532 (external pygidium), AMF80533 (internal pygidium), AMF80534 (internal pygidium), AMF80535 (internal pygidium), AMF80536a/b (external/internal pygidium), AMF80537 (external hypostome), AMF80539 (external cranidium), AMF80540 (internal librigena), AMF80541a/b (external/internal cranidium), AMF80542 (external cranidium), AMF80543 (external cranidium), AMF80544 (internal librigena), AMF80545 (internal cranidium), AMF80546 (internal pygidium), AMF80547 (internal pygidium), AMF80549 (partial external cranidium), AMF80550 (external cranidium), AMF80551 (internal cranidium), AMF80552 (internal cranidium), AMF80553 (partial external pygidium), AMF80554 (external pygidium), AMF80555 (internal pygidium), AMF80556 (internal pygidium), AMF80557a/b (external/ internal cranidium), AMF80558 (external cranidium), AMF80559 (external cranidium), AMF80560 (external cranidium), AMF80561 (external cranidium), AMF80562 (external cranidium), AMF80563 (external cranidium), AMF80564 (external cranidium), AMF80565 (external pygidium), AMF80566 (partial external cranidium). From NU L652: AMF80548 (partial external pygidium), AMF80567 (external cranidium), AMF80568 (external pygidium), AMF80569a/b (external/internal pygidium), AMF80570a/b (external/internal pygidium), AMF80571a/ b (external/internal pygidium).

Locality. Type—NU L894. Others—NU L427, NU L652.

Emended diagnosis. Cranidium flat, coarsely punctate with strong nodular ornament; glabellar length equal to width, anterior margin does not touch anterior border. Pygidial axis triangular in section, created by median node down axis, flanked by smaller nodes; distinct lateral lobes; 12–15 axial rings, 11–13 pleural ribs.

Remarks. The above diagnosis was emended to factor in glabellar length and that the glabella does not touch the anterior border in available specimens. There is also a furrow on either side of the pygidial axis, which separates the lateral lobes described by Engel & Morris (1984). Monodechenella speciosa is similar to M. subtriangularis , but they differ in ornamentation and numbers of pygidial rings and ribs. Monodechenella speciosa also resembles M. decisegmenta , but the former has small, relatively elevated eyes and a triangular pygidial axis ( Engel & Morris 1984).