The Echinoid Directory

Lutetiaster Lambert, 1920, p. 27

Diagnostic Features
  • Test ovate to cordiform with shallow anterior sulcus; posterior face truncate.
  • Apical disc subcentral; ethmolytic with 4 gonopores.
  • Anterior ambulacrum weakly sunken from apex to peristome; pore-pairs small and uniserially arranged.
  • Paired ambulacra petaloid; petals sunken, parallel-sided, with little perradial space; cruciform, the anterior petals being similar in length or slightly longer than the posterior petals.
  • Peristome kidney-shaped and facing obliquely forwards. Labrum projecting to cover peristome in oral view.
  • Plastron plating with subquadrate labral plate and large, symmetical sternal plates. Episternal plates biserially offset.
  • Periproct subcircular, on posterior truncate face; bounded on oral surface by interambulacral plates 5a/b.
  • Peripetalous and lateroanal fascioles present; peripetalous fasciole deeply indented between petals.
Distribution
Eocene to Miocene, circum-Mediterranean region.
Name gender masculine
Type
Spatangus subglobosus Lamarck, 1816, p. 33; by original designation.
Species Included
  • L. subglobosus (Lamarck, 1816); Eocene, France [L. laubei de Loriol, 1891 is a synonym.]
  • Many other species listed by Lambert & Thiery (1921), including L. cavernosus de Loriol.
Classification and/or Status

Spatangoida, Paleopneustina, Schizasteridae.

Subjective junior synonym of Linthia Desor, 1853.

Remarks
Differs from Linthia only in having the periproct transverse rather than longitudinal. In fact, many of the species listed by Lambert & Thiery (1924, p. 521) as Lutetiaster have periprocts that are circular to weakly longitudinal (e.g. L. cavernosus de Loriol, L. trechmanni Hawkins). Taller species tend to have more vertically elongate periprocts. I agree with Mortensen (1951, p. 238) that the difference in shape of the periproct is not stable or sufficient to merit generic differentiation. The difference in labral shape and elongation may prove a means of further dividing this taxon.