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 1959 ML78
    |    |    `--*P. parvus Koenig & Niewoehner 1959 ML78
    |    |--Clistocrinus Kirk 1937 [=Clithrocrinus Kirk 1937] ML78
    |    |    `--*C. pyriformis Kirk 1937 [=*Clithrocrinus pyriformis] ML78
    |    |--Lampadosocrinus Strimple & Koenig 1956 ML78
    |    |    `--*L. minutus (Peck 1936) [=Dichostreblocrinus minutus] ML78
    |    |--Neolageniocrinus Arendt 1970 ML78
    |    |    `--*N. shichanensis Arendt 1970 ML78
    |    |--Lageniocrinus deKoninck in deKoninck & LeHon 1854 ML78
    |    |    |--*L. seminulum deKoninck in deKoninck & LeHon 1854 ML78
    |    |    `--L. jacksoni ML78
    |    `--Acariaiocrinus Wanner 1924 [incl. Streptostomocrinus Yakovlev 1927] ML78
    |         |--*A. clavulus Wanner 1924 ML78
    |         `--‘*Streptostomocrinus’ caryophylloides Yakovlev 1927 ML78
    `--Streblocrininae [Pilidiocrininae] ML78
         |--Streblocrinus Koenig & Meyer 1965 ML78
         |    `--*S. brachiatus Koenig & Meyer 1965 ML78
         |--Atremacrinus Wanner 1929 ML78
         |    `--*A. calyculus Wanner 1929 ML78
         |--Coenocystis Girty 1908 [=Coencystis (l. c.)] ML78
         |    `--*C. richardsoni Girty 1908 ML78
         |--Dichostreblocrinus Weller 1930 ML78
         |    `--*D. scrobiculus Weller 1930 ML78
         |--Hemistreptacron Yakovlev 1926 ML78
         |    `--*H. abrachiatum Yakovlev 1926 ML78
         |--Pilidiocrinus Wanner 1937 ML78
         |    |--*P. permicus Wanner 1937 ML78
         |    `--P. hackeri U78
         `--Tytthocrinus Weller 1930 [incl. Octocrinus Peck 1936] ML78
              |--*T. comptus Weller 1930 ML78
              `--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).