WoRMS source details
Améziane, N.; Eléaume, M.; Roux, M. (2023). Classification of Isocrinida (Echinodermata: Crinoidea) with the description of a new extant genus and species from the western Pacific. Zoological Journal of the Linnean Society.
479921
10.1093/zoolinnean/zlad101 [view]
Améziane, N.; Eléaume, M.; Roux, M.
2023
Classification of Isocrinida (Echinodermata: Crinoidea) with the description of a new extant genus and species from the western Pacific
Zoological Journal of the Linnean Society
Publication
Previous molecular phylogenetic reconstructions have highlighted frequent convergences and iterations of external morphological characters
during the evolution of crinoids. Classifications of extant and fossil crinoids based on these characters need to be thoroughly revised. This is
particularly the case for the Isocrinida. We propose a new classification of this order based on molecular data and ontogenetic analysis of the
derived characters displayed on ossicles and their articulations. The argument is strengthened by the discovery and description of a species
belonging to a new genus (Panglaocrinus isseliformis gen. nov., sp. nov.) closely related to the genus Isselicrinus, which was abundant and
widespread during the Late Cretaceous and Eocene. Extant Isocrinida appear to be divided into two major lineages that we interpret as two distinct
families: Isocrinidae and Balanocrinidae. Isocrinidae are represented by the subfamily Metacrininae (genera Metacrinus and Saracrinus),
while Balanocrinidae comprise four subfamilies: Balanocrininae (Neocrinus), Diplocrininae (Endoxocrinus and Teliocrinus), Isselicrininae
(Panglaocrinus), and Proisocrininae (Proisocrinus). In the absence of molecular data, the genus Cenocrinus has not been attributed to any subfamily,
but its close relationship to Balanocrinidae is suggested. Possible relationships between Mesozoic and modern taxa are discussed, although
descriptions of arms in the palaeontological record are often important details.
Date
action
by
Panglaocrinus Améziane, Eléaume & Roux, 2023 (original description)
Panglaocrinus isseliformis Améziane, Eléaume & Roux, 2023 (original description)
Panglaocrinus isseliformis Améziane, Eléaume & Roux, 2023 (original description)
Holotype MNHN MNHN-IE-2007-13, geounit Sulu Sea, identified as Panglaocrinus isseliformis Améziane, Eléaume & Roux, 2023
Diagnosis
Two primibrachials; trend to decrease of proximal brachitaxes length; trend to development of marginal crenulae or ... [details]
Diagnosis
Usually stalk symplexies of balanocrinine type, cirri oriented upwards or moderately downwards, usually embayed ... [details]
Diagnosis
for Isocrinida
Aboral cup cryptodicyclic and poorly individualized forming a gradual transition between stalk and crown; ... [details]
Diagnosis
More than two primibrachials, cryptosynarthry at IBr1 + 2, except Eometacrinus, always muscular synarthry at IIBr1 + 2. [details]
Diagnosis
Lozenge-shaped cirrals, narrow and long areolas in stalk symplexies, absence of cryptosymplexies in stalk. [details]