The Echinoid Directory

Homolampas Agassiz, 1874, p. 137

[pro Lissonotus Agassiz, 1869, p. 273, non Gistl, 1848 ]

Diagnostic Features
  • Test ovate with faint anterior sulcus; depressed in profile with flattened base and top.
  • Apical disc ethmolytic, with 3 gonopores.
  • Anterior ambulacrum narrow and more or less flush; plates as tall as wide aborally. Pore-pairs rudimentary and tube-feet simple.
  • Other ambulacra non-petaloid and flush. Pore-pairs small and becoming gradually smaller and more widely spaced towards ambitus.
  • Periproct on short vertical truncate face.
  • Peristome wider than long; kidney-shaped; somewhat sunken.
  • Labral plate narrow and wedge-shaped, extending to second or third ambulacral plate; only just contacting sternal plates. Paired sternal plates triangular with tuberculation confined to posterior part only. Episternal plates paired and tapered inwards to the posterior.
  • Aboral tuberculation mostly fine and uniform but with a few large primary tubercles sunken in camellae in anterior columns of interambulacra 4 and 1, and the posterior columns of interambulara 2 and 3. Primary tubercles non-crenulate and forming internal ampullae.
  • Oral tubercles prominent laterally and arranged in distinct rows. Areoles weakly sunken and parapet typically helically spiraled.
  • Well-developed bilobed subanal fasciole enclosing ambulacral plates 6-9; some traces of anal branches occasionally seen.
  • Peripetalous fasciole present in some species (not in the type).
Distribution
Recent, Tropical West Atlantic and Malay Region: 550-4500 m.
Name gender feminine
Type
Lissonotus fragilis Agassiz, 1869, p. 273, by original designation.
Species Included
  • H. fragilis (Agassiz, 1869); Recent, Caribbean.
  • H. lovenoides Mortensen, 1948; Recent, Celebes.
Classification and/or Status

Spatangoida, Micrasterina, Maretiidae.

Monotypic.

Remarks Close to Pseudolovenia but differing in the absence of aboral fascioles and by its virtually flush anterior ambulacrum. Differs from Araeolampas by its noncrenulate, deeply sunken primary tubercles, apical disc with 3 gonopores (4 in Araeolampas) and presence of globiferous pedicellariae.

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

Serafy, D. K. 1974. A new heart-urchin, Araeolampas atlantica, new genus, new species, from the North Atlantic and notes on the closely related Homolampas. Proceedings of the Biological Society of Washington 87, 41-48.