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 Conocrinus). Radial articular facet wide, with large muscle fossae, surrounding narrow axial canal. Articulation between brachials 1-2 cryptosynarthrial or synostosial (possibly muscular in [fossil] Dunnicrinus mississippiensis). 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.