The Echinoid Directory

Nacospatangus A. Agassiz, 1873, p. 189

[=Pseudomaretia Koehler, 1914, p. 107, type species Maretia alta Agassiz, 1863; =Gonimaretia Clark, 1917, p. 240, type species Gonimaretia tylota Clark, 1917; = Nacopatagus Agassiz, 1881, p. 219 (nomen vanum) ]

Diagnostic Features
  • Test small without anterior sulcus; oral surface flat and arched aborally.
  • Apical disc ethmolytic, with 3 gonopores; genital plate 2 projects behind the posterior oculars.
  • Anterior ambulacrum very narrow; pore-pairs small, simple isopores (no specialized tube-feet).
  • Other ambulacra petaloid and flush; closed distally.
  • Anterior paired petals with pore-pairs in anterior column more or less rudimentary except distally.
  • Periproct on short truncate face; variably invaginated; framed by interambulacral plates 5a/b orally.
  • Peristome wider than long; kidney-shaped. Phyllodes inconspicuous.
  • Labral plate longitudinally elongate; only just contacting sternal plates; extending to second ambulacral plate.
  • Paired sternal plates long and narrow and fully tuberculate. Episternal plates contracting posteriorly.
  • Aboral surface with small uniform tuberculation only.
  • Subanal fasciole present; enclosing two funnel-building tube-feet (4 plates).
Distribution
Recent, Pacific; 30-120 m.
Name gender masculine
Type
Nacospatangus gracilis Agassiz, 1873, p. 189, by original designation.
Species Included
  • N. gracilis (Agassiz, 1873); Recent, Juan Fernandez.
  • ?N. depressus Clark, 1917; Recent, South California (possibly = Goniomaretia laevis Clark).
  • N. tylota (Clark, 1917); Recent, Philippines
  • N. alta (Agassiz, 1863); Recent, Indo-Pacific.
  • N. laevis (Clark, 1917); Recent, Gulf of California.
  • N. oblonga Mortensen, 1950; Recent, Galapgos Islands.
  • N. interrupta (Studer, 1880); Recent, Australia.
Classification and/or Status

Spatangoida, Micrasterina, Maretiidae.

?

Remarks

Nacospatangus, Gonimaretia and Pseudomaretia are very similar taxa separated largely on the degree to which primary tubercles are developed in the lateral interambulacra, and the degree to which the periproct is sunken. Mortensen (1951) found that larger individuals than the type had pore-pairs developed distally in the anterior column of the anterior petals. He therefore considered that the genera should probably be synonymized. The type species is based on a juvenile just 17 mm long and differs in having no primary aboral tubercles.

Agassiz, A. 1873. The echini collected on the Hassler expedition. Bulletin of the Mueum of Comparative Zoology, Harvard College 3, 189-190.

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