Chambersaecrinus Mironov & Sorokina, 1998b

Roux, Michel & Lambert, Philip, 2011, Two new species of stalked crinoids from the northeastern Pacific in the genera Gephyrocrinus and Ptilocrinus (Echinodermata, Crinoidea, Hyocrinidae). Effects of ontogeny and variability on hyocrinid taxonomy, Zootaxa 2825, pp. 1-54 : 18

Subgenus Chambersaecrinus Mironov & Sorokina, 1998b

Type species of the subgenus: Ptilocrinus brucei Vaney, 1908 . Synonymy: Mironov & Sorokina, 1998b: 52.

Emended diagnosis. Subgenus of Ptilocrinus with tegmen variously inflated; conspicuous radial bridges elevated above tegmen from orals to Br5 or more; cover plates well differentiated on tegmen; orals concave (median depression); anal sac always conspicuously higher than oral cone. Tendency for larger interradial tegminal plates to be arranged into a median row when tegmen inflated. Distal stalk syzygies with crenularium weakly differentiated.

Included species. P. brucei Vaney, 1908 [= P. (Chambersaecrinus) flexibilis Mironov & Sorokina, 1998b ] (southwestern Indian Ocean, 4,070 to 5,474 m); P. ( Ptilocrinus ) s tukalinae Mironov & Sorokina, 1998b [= P. (? Ptilocrinus ) perforatus Mironov & Sorokina, 1998b] (north and southwestern Pacific, southwestern Indian Ocean, 4,664 to 6,145 m); P. tasmaniaensis Améziane & Roux, 2011 (off Tasmania, 1,715 to 1,815 m).

Remarks. The detailed description of the type series of P. (Ptilocrinus) stukalinae by Mironov & Sorokina (1998b) documented the wide range of variation in crown characters. The single known specimen of P. (? Ptilocrinus ) perforatus falls within this range. Moreover, its mesistele symplexies strongly resemble those of P. stukalinae suggesting that they belong to the same species. It has interradial tegminal plates in a median row, confirming the attribution of P. stukalinae to the subgenus Chambersaecrinus . P. stukalinae has a well developed anal sac which seems to be adjacent to the tegmen margin (personal communication of A. Mironov). P. (Chambersaecrinus) flexibilis was established on the basis of a single incomplete specimen (aboral cup broken, stalk unknown) without significant differences from P. brucei .