- Test moderately thin and fragile.
- Apical disc 40-50% test diameter; monocyclic. Genital plate 2 slightly enlarged compared to other genital plates. All plates covered in scattered tubercles.
- Interambulacra with up to 10 plates in a series. Primary tubercles perforate and non-crenulate (the most adapical tubercles may have a trace of crenulation on their adapical side). Areoles ovate; incised; separated by scrobicular circles except immediately beside the peristome.
- Scrobicular tubercles hardly differentiated. Extrascrobicular zones not extensive; densely covered in heterogeneous secondary tubercles and granules.
- No sutural pits or furrows.
- Ambulacra weakly sinuous. Pore zones not incised; pore-pairs subconjugate to conjugate, the two pores widely separated. Perradial zone fully tuberculate, with marginal series of contiguous primary tubercles and inner zone of smaller secondary tubercles.
- Peristome a little smaller than apical disc. Interradial plate series not quite reaching the peristome; ambulacral plates uniserial in each column.
- Primary spines long and relatively slender; tapering or ending in small crown. Collar and neck short; shaft ornamented in relatibvely coarse irregular thorns; surface between thorns covered in fine cortical hairs.
- Secondary spines flattened but not adpressed
||Stephanocidaris bispinosa Agassiz, non Lamarck, 1816 [=Phyllacanthus australis Ramsay, 1885]
||Only the type species
|Classification and/or Status
||Cidaroidea, Cidaridae, Cidarinae
Homonym of Stephanocidaris Agassiz, 1863 [itself an objective junior synonym of Goniocidaris Desor, in Agassiz & Desor 1846, according to Mortensen (1928)]
Subjective junior synonym of Prionocidaris Agassiz, 1863
||The species on which this taxon was based was wrongly assigned by Agassiz. Mortensen (1928) treated this as a junior synonym of Prionocidaris.
Agassiz, A. 1872-1874. Revision of the Echini. Memoirs of the Museum of Comparative Zoology at Harvard College, 3: pts. 1-2: i-xii, 1-378, pls 1-49 (1872); pt. 3: 379-628 +1, pls 50-77 (1873); pt. 4: 629-762, pls 78-94 (1874).
Mortensen, T. 1928. A monograph of the Echinoidea. 1, Cidaroidea. C. A. Reitzel, Copenhagen.