Acrocrinidae

Springeracrocrinus conicus, from Webster et al. (2003).

Belongs within: Compsocrinina.

The Acrocrinidae are a group of crinoids known from the Carboniferous, characterised by the possession of a tall calyx containing intercalary plates (Ubaghs 1978).

Characters (from Ubaghs 1978): Crown ovoid to pyriform, with height exceeding greatest width; arms (where known) erect or pendent, biserial, pinnulate; calyx subconical, vaselike, tall ovoid, or subglobular, with two equal basals separated by suture between them oriented anteroposteriorly; radials five, laterally adjoining one another except C and D radials, which are separated by primanals; radials and basals not in contact but set apart by few to very many intervening supplementary plates collectively designated as intercalaries; tegmen flat to gently convex, with or without differentiated orals and having few or extremely numerous small plates, anal vent near posterior margin, inconspicuous or located at tip of anal pyramid. Column transversely circular, homeomorphic or heteromorphic, with columnal articular facets peripherally crenulate; axial canal diminutive, circular to distinctly quinquelobate in section.

<==Acrocrinidae
|--Planacrocrinus Moore & Strimple 1969 [Planacrocrininae]U78
| |--*P. ambix Moore & Strimple 1969U78
| `--P. conicusU78
|--AcrocrininaeU78
| |--Acrocrinus Yandell 1855U78
| | `--*A. shumardi Yandell 1855U78
| |--Amphoracrocrinus Moore & Strimple 1969U78
| | `--*A. amphora (Wachsmuth & Springer 1897) [=Acrocrinus amphora]U78
| `--Platyacrocrinus Moore & Strimple 1969U78
| `--*P. brentwoodensis (Moore & Plummer 1938) [=Acrocrinus brentwoodensis]U78
`--GlobacrocrininaeWM03
|--Caucacrocrinus Moore & Strimple 1969U78
| `--*C. urnula Moore & Strimple 1969U78
|--Dinarocrinus Moore & Strimple 1969U78
| `--*D. expansus (Strimple 1951) [=Acrocrinus expansus]U78
|--Metacrocrinus Moore & Strimple 1969U78
| `--*M. pumpkensis (Strimple 1949) [=Acrocrinus pumpkensis]U78
|--Protacrocrinus Moore & Strimple 1969U78
| `--*P. primitivus (Laudon & Beane 1937) [=Acrocrinus primitivus]U78
|--Globacrocrinus Moore & Strimple 1969U78
| |--*G. pirum (Moore & Plummer 1938) [=Acrocrinus pirum]U78
| `--G. rotundusU78
`--Springeracrocrinus Moore & Strimple 1969WM03
|--*S. intermedius (Springer 1926)WM03 [=Acrocrinus intermediusU78]
|--S. conicus Webster, Maples et al. 2003WM03
|--S. mjatschkowensisU78
`--S. praecursor (Springer 1926)WM03

*Type species of generic name indicated

References

[U78] Ubaghs, G. 1978. Camerata. In: Moore, R. C., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt T. Echinodermata 2. Crinoidea vol. 2 pp. T408–T519. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[WM03] Webster, G. D., C. G. Maples, R. Mawson & M. Dastanpour. 2003. A cladid-dominated Early Mississippian crinoid and conodont fauna from Kerman Province, Iran and revision of the glossocrinids and rhenocrinids. Journal of Paleontology 77 (Suppl. 3): 1–35.

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