Bathycrinidae

Mironov, Alexandr N. & Pawson, David L., 2014, A new species of Western Atlantic sea lily in the family Bathycrinidae (Echinodermata: Crinoidea), with a discussion of relationships between crinoids with xenomorphic stalks, Zootaxa 3873 (3), pp. 259-274 : 272-273

Key to genera of the family Bathycrinidae

1a. Primibrachials elongate, ratio height/width of IBr2 varies from 1.50 to 1.69. Covering plates absent. Each primibrachial has two well-developed knobby processes (unknown for D. thieli )....................................... Discolocrinus

1b. Primibrachials not elongate, ratio height/width of IBr2 <1.22 (usually <1.0). Covering plates present. Some primibrachials without knobby processes or with one process.............................................................. 2

2a. Side plates and sacculi (the latter often rudimentary) present. Tube feet lack X-shaped plates. Knobby processes absent on IBr 2....................................................................................... Monachocrinus

2b. Side plates and sacculi absent. Tube feet with X-shaped plates. Knobby processes present on IBr 2.................... 3

3a. Every second articulation between pinnulars beyond the first pair flexible. Non-elongate (in Cingocrinus radiculatus ) or

slightly elongate (in Cingocrinus sp.) columnals in mesistele; maximum ratio height/diameter of columnal <2.0. Abutting surface of the knobby processes with tiny knobbles................................................... Cingocrinus 3b. Articulations between pinnulars beyond the first pair rigid. Elongate columnals in mesistele; maximum ratio height/diameter of columnal> 2.0. Abutting surface of the knobby processes with marked needlelike knobbles............... Bathycrinus