The Echinoid Directory

Jordaniaster Neumann, 1999, p. 176

Diagnostic Features
  • Test ovate with shallow but distinct anterior sulcus; posterior face truncate.
  • Apical disc ethmophract with four gonopores (genital plate 2 separates posterior genital plates but not the posterior ocular plates); a little anterior of centre.
  • Ambulacrum III modestly sunken from apex to peristome. Pore-pairs differentiated with prominent interporal ridge, presumably associated with funnel-building tube-feet; densely packed aborally.
  • Paired ambulacra petaloid; petals sunken and more or less parallel; closed distally. Interporal zone about same width as pore-pairs; pore-pairs elongate. Anterior petals reach almost to ambitus; posterior petals similar in length but not reaching ambitus and not diverging much.
  • Peristome D-shaped and slightly tilted towards anterior.
  • Labral plate longer than wide, extending to fourth ambulacral plate; with curved posterior suture. Sternal plates large and asymmetric with 5.b.2 larger and in broad contact with the labrum: 5.a.2 smaller and probably just meeting horn from labral plate (this part of the specimen obscured); median suture oblique. Episternal plates offset to rear of sternal plates.
  • Periproct small, situated towards top of posterior truncate face.
  • Peripetalous fasciole present (as a parafasciole, i.e. it includes occasional tubercles); indented by one interambulacral plate behind anterior petals.
  • Aboral tuberculation of scattered small tubercles set in a groundmass of granules.
Distribution
Upper Cretaceous (Lower Cenomanian), Jordan.
Name gender masculine
Type
Jordaniaster husseini Neumann, 1999, p. 176, by original designation.
Species Included
  • Only the type species was originally included. However, Mecaster batnensis has a similar apical disc and should probably be included.
Classification and/or Status

Spatangoida, Hemiasterina, Hemiasteridae.

Monotypic.

Remarks

Although Neumann (1999) discusses how it differs from several genera, he does not mention how it is distinguished from Mecaster, with which it shares most similarity. However, the type species of Mecaster has an ethmolytic apical disc whereas Jordaniaster has a ethmophract disc with genital plate 2 separating the posterior genital plates.

Neumann, C. 1999. New spatangoid echinoids (Echinodermata) from the Upper Cretaceous of Jordan: their taxonomy and phylogenetic importance. Berliner geowissenschaft Abhandlungen E30, 175-189.