WoRMS note details

Diagnosis
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Bourgueticrinina with 5 undivided rays. Cup mostly elongate, cylindrical to spindle shaped, composed of a proximale superposed by basals and radials of equal or nearly equal height, or high basals and shorter radials (proximale undifferentiated or absent in <i>Conocrinus</i>). Radial articular facet wide, with large muscle fossae, surrounding narrow axial canal. Articulation between brachials 1-2 cryptosynarthrial or synostosial (possibly muscular in [fossil] <i>Dunnicrinus mississippiensis)</i>. First pinnule abaxial on brachial 4. Discrete sutures in proximale of some specimens indicate derivation by fusion of a few disk-shaped proximal columnals; articular facet at base of proximale wide, circular in cross section and joined to topmost columnal by synostosis, or elliptical and joined by synarthry; uppermost free columnals cylindrical and slightly shorter than more distal ones, or elliptical in section and similar to more distal columnals; synarthrial articulation with proximale and full size of uppermost free columnal in many specimens indicate that the formation of new columnals below the proximale is restricted to juveniles; form and size of columnals changing during growth and varying through a single column (cylindrical, barrel shaped, or with elliptical section at ends and constricted medially). Anchoring via branched radicular cirri on some distal columnals.
Hess H (2011) Bourgueticrinina. In: Hess H, Messing CG, Ausich WI (Eds.), Treatise on Invertebrate Paleontology, Part T, Echinodermata 2 Revised, Crinoidea, vol. 3. University of Kansas Press, Lawrence, Kansas, pp. 146–158.