The Echinoid Directory

Paleopneustes A. Agassiz, 1873, p. 223

[=Palaeopneustes Duncan, 1889, p. 223 (nomen vanum); ?=Prosostoma Pomel, 1883, p. 55, type species Asterostoma jimenoi Cotteau, 1870; ?=Pseudasterostoma Duncan, 1889, p. 203, type species Asterostoma jimenoi Cotteau, 1870 ]

Diagnostic Features	Test ovate with convex anterior; flat base and hemispherical upper surface. Apical disc ethmolytic with three gonopores (no gonopore in genital plate 2); central. Frontal ambulacrum narrow, with small pore-pairs that are almost vertically oriented supporting simple tube-feet; flush. Paired ambulacra petaloid; flush; extending towards ambitus. Pore-pairs not elongate; petals open distally, with one or two occluded plates at the ends. Peristome towards anterior; kidney-shaped. Labrum projecting over peristome in oral view. Labral plate elongate; extending to ambulacrum plate 3. Sternal plates symmetrical. Episternal plates paired and opposed; not indented by ambulacral plates. Ambulacral plate 8 abuts rear suture of episternal plates. Interambulacral zone 1 meridoplacous orally; other interambulacral zones amphiplacous. Periproct marginal; large. No fascioles in adult but marginal and peripetalous fascioles in juveniles. Aboral tuberculation heterogeneous; scattered tubercles over all plates. On oral surface periplastronal areas free of tubercles.
Distribution	Miocene to Recent, Carribean, Japan.
Name gender	feminine
Type	Paleopneustes cristatus A. Agassiz, 1873, p. 223, by original designation.
Species Included	P. cristatus Agassiz, 1873; Pleistocene to Recent, Caribbean (illustrations of Pleistocene fossil). P. psoidoperiodus Nisiyama, 1968; Pliocene, Japan. P. periturus Nisiyama, 1968; Pliocene, Japan. P. lepidus Nisiyama, 1968; Miocene, Japan.
Classification and/or Status	Spatangoida, Paleopneustina, Paleopneustidae. Probably monophyletic.
Remarks	Differs from Archaeopneustes in having a less pronounced labral projection, more anterior peristome, tubercle-free periplastronal zones, and no large primary tubercles aborally. Differs from Megapetalus by the complete absence of a frontal groove, and by having relatively narrower ambulacral zones aborally. A detailed description of this taxon was given by Chesher (1968). Agassiz, A. 1873. Bulletin of the Mueum of Comparative Zoology, Harvard 3, p. 188. Mortensen, T. 1950. A monograph of the Echinoidea. V. Spatangoida 1. C. A. Reitzel, Copenhagen. Chesher, R. H. 1968. The systematics of sympatric species in West Indian spatangoids: a revision of the genera Brissopsis, Plethotaenia, Paleopneustes, and Saviniaster. Studies in Tropical Oceanography 7, 1-168, pls 1-35. Nisiyama, S. 1968. The echinoid fauna from Japan and adjacent regions, Part II. Palaeontological Society of Japan, Special Paper 13, 1-491, pls 19-30.