Metacrininae Klikushin 1977
- Dataset
- Early Miocene stalked crinoids (Echinodermata) from the southern Rhodanian basin (southeastern France). Paleoenvironments and taxonomy
- Rank
- SUBFAMILY
Classification
- kingdom
- Animalia
- phylum
- Echinodermata
- class
- Crinoidea
- order
- Isocrinida
- family
- Isselicrinidae
discussion
Remarks. Metacrininae differ from all other Isocrinida in having more than 2 IBr with IBr 2 bearing the first pinnule, and a muscular synarthry at IIBr 1 + 2. The primibrachitaxis has a synostose at IBr 4 + 5 when the number of IBr is> 4. Their stalk symplexies display closed ZP and axial grooves in ZIP (Roux 1977, 1981). Two genera with a synostosis at IBr 1 + 2 are distinguished in extant Metacrininae (Améziane-Cominardi 1991, Bourseau and Roux 1989, Hess 2011, Roux 1981): Saracrinus with usually 3 – 6 IBr (mode 4) and <10 IIBr, and Metacrinus having usually> 4 IBr (mode 7) and> 10 IIBr. The Eocene species Metacrinus fossilis Rasmussen, 1980 and Eometacrinus australis Baumiller and Gazdzicki, 1996 have a proximal crown with 5 IBr and 9 – 10 IIBr. Such an arm pattern is intermediate between Saracrinus and Metacrinus. Eometacrinus differs in having an axial ligamentary synarthry at IBr 1 + 2. Metacrinus seymouriensis Rasmussen, 1980 is only known from pluricolumnals found in the Maastrichtian.
Name
- Homonyms
- Metacrininae Klikushin 1977