The Echinoid Directory

• Test ovate without anterior sulcus. In profile relatively depressed with strongly overarching hood to the periproct. Bluntly pointed to rear.
• Apical disc ethomlytic with 4 gonopores; closer to anterior than centre.
• Anterior ambulacrum narrow and flush; pore-pairs small and rudimentary.
• Other ambulacra petaloid, flush, narrow and parallel; the two clumns close and parallel; anterior pair extending most of the distance to the ambitus in plan view; posterior pair much shorter.
• Periproct large; inframarginal on overhung truncation; opening taller than wide.
• Peristome wider than long; kidney-shaped with projecting labrum.
• Labral plate very short and wide; sternal plates large and shield-like, hardly indented at posterior by ambulacral zones. Episternal plates offset.
• No large primary tubercles differentiated aborally.
• Peripetalous fasciole present, passing beneath the ambitus around the anterior and at some distance beneath the anterior paired petals. Lateroanal fasciole present.

Late Oligocene - Early Miocene (Burdigalian), Austria and Australia.

Brissomorpha fuchsi Laube, 1871, p. 73, by original designation. Lectotype: Natural History Museum, Wien 1866.XX.18.

• B. fuschsi Laube, 1871; Early Miocene, Austria
• B. nelsoni (McCoy, 1882); Late Oligocene, Australia

Spatangoida, Paleopneustina, Prenasteridae.

Monotypic. Subjective junior synonym of Prenaster Desor, 1853 (see Kroh, 2005).

The type species was until recently poorly known and Mortensen (1950) suspected it was related to Heterobrissus. However, Kroh (2005) has restudied the type material and demonstrated that this taxon is synonymous with Prenaster. Both have an identical fasciole arrangement and very similar ambulcara. The only difference of any note is that in the type species of Brissomorpha the periproct is somewhat more overarched and inframarginal than in the type species of Prenaster.

Laube, G. C. 1871. Die Echinoiden der Osterreich-Ungarischen oberen Tertiarablagergungen. Abhandlunge der k. k. Geologisch Reichsanstalt Wien 5.

Kroh, A., 2005: Catalogus Fossilium Austriae. Volume 2 Echinoidea neogenica. lvi+202 pp., 82 pls., 94 figs., 11 tabs., Österrischen. Akademie der Wissenschaften, Wien.