The Echinoid Directory

Rumphia Desor, 1857, p. 229

[=Peronellites Hayasaka & Morishita, 1947, p. 101; type species Peronellites ovalis Hayasaka & Morishita, 1947; =Polyaster Michelin, 1859, non Gray, 1840; =Michelinia Dujardin & Hupe, 1862, p. 560, type species Polyaster elegans Michelin, 1859 [=Peronella lesueuri Agassiz, 1841]]

Diagnostic Features
  • Test ovate to subpentagonal in outline; margin relatively thin and base broad and flat.
  • Apical disc central with 4 gonopores; gonopores within disc rather than interambulacral zones. Hydropores scattered over surface of disc.
  • Petals well developed; relatively long; tending to converge distally. Anterior petal often slightly longer than rest.
  • Interambulacral zones very much narrower than ambulacral zones. Oral surface composed at least five pairs of post-basicoronal plates in both ambulacral and interambulacral zones.
  • Periproct oral, close to the posterior margin. Opening bounded by third, fourth or fifth post-basicoronal plates.
  • Food grooves simple perradial trunks.
Miocene to Recent of the Indo-Pacific.
Name gender feminine
Laganum rostratum L. Agassiz, 1841 (=Laganum lesueuri L. Agassiz, 1841, by original designation.
Species Included
  • R. lesueuri (Agassiz, 1841); Upper Miocene to Recent, Indo-Pacific.  
  • R. ricta (Gregory, 1892); Pleistocene, Western Australia.
  • R. orbicularis (Leske, 1778); Pleistocene to Recent, Western Australia.
  • R. pellucida (Doderlein, 1885), Pleistocene-Recent, Japan.
  • R. hinemoae (Mortensen, 1948); Recent, New Zealand.
  • R. japonica (Mortensen, 1948); Pleistocene-Recent, Japan.
  • R. keinsis (Mortensen, 1948); Recent, Kei Islands.
  • R. affinis (McClelland, 1840); Recent; Indian Ocean.
Classification and/or Status

Clypeasteroida; Scutellina; Laganiformes; Laganidae; Laganinae.

Presumed monophyletic.


Durham (1955) resurrected this genus for species with the periproct situated close to the margin and opening through the fourth or fifth pair of post-basicoronal interambulacral plates. No other laganiform has the periproct lying posterior to the second pair of post-basicoronal plates.

Desor, E. 1855-1858. Synopsis des Echinides fossiles. Paris, Reinwald.

Mortensen, T. 1948. A Monograph of the Echinoidea IV.2 Clypeasteroida. C. A. Reitzel, Copenhagen.

J. W. Durham 1955 Classification of clypeasteroid echinoids. University of California Publications in Geological Sciences 31, 73-191.

Nisiyama, S. 1968. The echinoid fauna from Japan and adjacent regions part II. Palaeontological Society of Japan Special Papers 13, 1-491, pls 1-30.