The Echinoid Directory

• Test ovate with very faint anterior sulcus; low arched aborally and more or less concave on oral surface. Ambitus rather sharp.
• Apical disc ethmolytic, with 4 gonopores; genital plate 2 projects behind the posterior oculars.
• Anterior ambulacrum narrow and flush; pore-pairs small, simple isopores. Other ambulacra petaloid and flush.
• Anterior paired petals narrow and flush with pore-pairs in anterior column rudimentary. Posterior petals equally narrow and open distally; both columns of pore pairs equally developed.
• Periproct on short steeply undercut truncate face.
• Peristome wider than long; kidney-shaped.
• Labral plate narrow and elongate; only just contacting sternal plates; extending to fourth ambulacral plate.
• Paired sternal plates narrow and triangular with tuberculation confined to posterior. Episternal plates contracting posteriorly.
• Aboral tuberculation heterogeneous with numerous coarse tubercles in all interambulacra. Primary tubercles sunken. On oral surface lateral tubercles arranged in distinct rows, with slightly sunken areoles and spiral parapet.
• Subanal fasciole present in juveniles only.

Recent, Australia and New Zealand; 150-475 m.

Paramaretia multituberculata Mortensen, 1950, p. 160, by original designation.

• P. multituberculata Mortensen, 1950; Recent, Australia and New Zealand.
• P. peloria (Clark, 1916); Recent, Australia.

Spatangoida, Micrasterina, unnamed family 2

Monophyletic.

Distinguished from Maretia by its narrow, parallel-sided petals, with the anterior column in the anterior paired petals almost completely obliterated. Furthermore, the fact that the ambulacra do not indent the posterior interambulacra to the rear of the episternal plates is highly distinctive. It is distinguished from Nacospatangus by having four gonopores.

Mortensen, T. 1951. A monograph of the Echinoidea. V.2 Spatangoida. C. A. Reitzel, Copenhagen.