The Echinoid Directory

• Test ovate with shallow anterior sulcus; inflated in profile with flat top.
• Apical disc ethmolytic, with 4 gonopores. Positioned far anterior of centre.
• Anterior ambulacrum weakly sunken; pore-pairs and tube-feet specialized and densely packed aborally.
• Other ambulacra also sunken, anterior and posterior paired petals approximately similar in length; long, parallel-sided and closed distally. Anterior petals almost at 180 degrees and flexed anterior slightly at their tips. No occluded plates distally.
• Periproct small and rather low on posterior face.
• Peristome anterior; kidney-shaped; sunken and inclined towards anterior. Labrum projecting over it to a greater or lesser extent.
• Labral plate short and wide; in broad contact with sternal plates; not extending beyond first ambulacral plate.
• Sternum broad and symmetrical. Episternal plates more or less opposite and forming the rear portion of the oral surface of the plastron. Ambulacral plate 7 or 8 at rear of sternal plate 5.b.2.
• Ambulacral zones on oral surface narrow and bowed. Subanal pore-pairs and tube-feet differentiated.
• Interambulacrum 1 meridoplacous, interambulacrum 4 always amphiplacous.
• Aboral tuberculation fine, uniform and dense. Oral tubercles also dense and uniform.
• Well-developed peripetalous and latero-anal fascioles. Peripetalous fasciole deeply indented in lateral interambulacra.

Eocene to Recent, Australia and New Zealand, ?Mediterranean.

Desoria australis Gray, 1851 , p. 133, by original designation.

• P. australis (Gray, 1851); Pleistocene to Recent, Australia.
• P. antiaustralis (Tate, 1885); Early Miocene, South Australia.
• P. preaustralis McNamara, 1985; Late Eocene, Australia.
• P. philipi McNamara, 1985; Late Oligocene, Victoria, Australia.
• P. synapticus (Henderson, 1975), Eocene, New Zealand.
• ?P. corsicus Cotteau, in Locard, 1877; Lower Miocene, circum-Mediterranean.

Spatangoida, Paleopneustina, Schizasteridae.

Presumed monophyletic.

The genus and its species is discussed in admirable detail by McNamara (1985). It differs from most other schizasterids in having ambulacrum III narrow and only slightly depressed on the aboral surface. It is distinguished from Linthia only by its shallower frontal groove and more anterior apical disc.

McNamara, K.J. 1985. Taxonomy and evolution of the Cainozoic spatangoid echinoid Protenaster. Palaeontology 28, 311-330.

Pomel, A. 1883. Classification méthodique et genera des Échinides vivante et fossiles. Thèses présentées a la Faculté des Sciences de Paris pour obtenir le Grade de Docteur ès Sciences Naturelles, 503, 131 pp. Aldolphe Jourdan, Alger.