Streblocrinidae

Posterior (above) and aboral views of Tytthocrinus inconsuetus, from Peck & Connelly (1951).

Belongs within: Cyathocrinida.

The Streblocrinidae are a group of armless crinoids known from the Middle Devonian to the Upper Permian (Moore et al. 1978).

Characters (from Moore et al. 1978): Theca typically composed of infrabasals, basals, and orals; abrachiate; radials and anal plate absent in all but most primitive genera; posterior oral commonly with hydropore and separating BC and DE orals; orals primitively above basals in interradial position, and anal opening on lower right side of posterior oral and upper right shoulder of CD basal.

Streblocrinidae
|--Pentececrininae [Acariaiocrininae, Lageniocrininae]ML78
| |--Pentececrinus Koenig & Niewoehner 1959ML78
| | `--*P. parvus Koenig & Niewoehner 1959ML78
| |--Clistocrinus Kirk 1937 [=Clithrocrinus Kirk 1937]ML78
| | `--*C. pyriformis Kirk 1937 [=*Clithrocrinus pyriformis]ML78
| |--Lampadosocrinus Strimple & Koenig 1956ML78
| | `--*L. minutus (Peck 1936) [=Dichostreblocrinus minutus]ML78
| |--Neolageniocrinus Arendt 1970ML78
| | `--*N. shichanensis Arendt 1970ML78
| |--Lageniocrinus deKoninck in deKoninck & LeHon 1854ML78
| | |--*L. seminulum deKoninck in deKoninck & LeHon 1854ML78
| | `--L. jacksoniML78
| `--Acariaiocrinus Wanner 1924 [incl. Streptostomocrinus Yakovlev 1927]ML78
| |--*A. clavulus Wanner 1924ML78
| `--‘*Streptostomocrinus’ caryophylloides Yakovlev 1927ML78
`--Streblocrininae [Pilidiocrininae]ML78
|--Streblocrinus Koenig & Meyer 1965ML78
| `--*S. brachiatus Koenig & Meyer 1965ML78
|--Atremacrinus Wanner 1929ML78
| `--*A. calyculus Wanner 1929ML78
|--Coenocystis Girty 1908 [=Coencystis (l. c.)]ML78
| `--*C. richardsoni Girty 1908ML78
|--Dichostreblocrinus Weller 1930ML78
| `--*D. scrobiculus Weller 1930ML78
|--Hemistreptacron Yakovlev 1926ML78
| `--*H. abrachiatum Yakovlev 1926ML78
|--Pilidiocrinus Wanner 1937ML78
| |--*P. permicus Wanner 1937ML78
| `--P. hackeriU78
`--Tytthocrinus Weller 1930 [incl. Octocrinus Peck 1936]ML78
|--*T. comptus Weller 1930ML78
`--T. inconsuetus (Peck 1936) [=*Octocrinus inconsuetus]ML78

*Type species of generic name indicated

References

[ML78] Moore, R. C., N. G. Lane, H. L. Strimple, J. Sprinkle & R. O. Fay. 1978. Inadunata. In: Moore, R. C., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt T. Echinodermata 2. Crinoidea vol. 2 pp. T520–T759. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[U78] Ubaghs, G. 1978. Skeletal morphology of fossil crinoids. In: Moore, R. C., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt T. Echinodermata 2. Crinoidea vol. 1 pp. T58–T216. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

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