WoRMS note details

Antedonidae with centrodorsal rounded, low hemispheric or conical, usually with cirrus-free aboral apex, sometimes with deep aboral pit. Cirrus sockets 30-200, crowded, commonly regularly alternating in 4-7 circles. Centrodorsal cavity moderate. Cirri long and stout, laterally compressed. Either 2 pairs of radial nerve canals and no basal rays, or one pair with basal rays present. Radials with short exposed surface or concealed. Radial articular facet high, commonly concave with aboral ligament fossa and interarticular ligament fossae sloping outward; muscle fossae almost parallel to oral-aboral axis, narrow, higher than interarticular ligament fossae, and separated by a median ridge and notch. Radial cavity moderate to large. Arms divided at primibrachials 2, rarely also at secundibrachials 2. Primibrachial 1 commonly with converging sides, may be overhung by lateral edge of primibrachial 2. Synarthrial articulations commonly embayed. First pinnule long, flagellate, with numerous short pinnulars. Distal pinnulars of proximal pinnules may bear rudimentary comb teeth.
Hess H, Messing CG (2011) Comatulida. In: Hess H, Messing CG, Ausich WI. Treatise on Invertebrate Paleontology, Part T, Echinodermata 2 Revised, Crinoidea, vol. 3. University of Kansas Press, Lawrence, Kansas, pp. 70–146.