Xenocrinidae
Classification
Phylum: Echinodermata
Class: Crinoidea
Order: Monobathrida
Family: Xenocrinidae (Miller, 1890)
Cincinnatian Genera: Xenocrinus
Geologic Range
Late Ordovician
Common Paleoecology
Xenocrinidae is an extinct family of stationary upper-level epifaunal suspension feeders
Description of the Family
- Median ray and anal ridges are conspicuous
- Radials usually adjoining each other in all interrays except posterior
- Interbrachial areas depressed and flexible, composed of small and irregular plates
- Stem quadrangular in cross section
- Sutures between some adjacent radials covered by small plates
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Treatise on Invertebrate Paleontology, Part T (1978):
Treatise on Invertebrate Paleontology, Part T (1978):
- Median ray and anal ridges conspicuous; radials usually adjoining each other in all interrays except posterior; sutures between some adjacent radials covered by small supplementary plates; fixed secundibrachs two, if there is further division, otherwise three to four to each half ray; few fixed tertibrachs may be present; interbrachial areas depressed, flexible composed of many small and irregular plates; CD interray with radial-like primanal and median anitaxis of prominent convex plates. Free arms 2, 3 or 4 per ray, unbranched, uniserial or composed of cuneiform and interlocking brachials. Stem quadrangular in cross section, with pentagonal axial canal.
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Xenocrinus
