Morphological disparity and systematic revision of the eocrinoid genus Rhopalocystis (Echinodermata, Blastozoa) from the Lower Ordovician of the central Anti-Atlas (Morocco)

The genus Rhopalocystis (Eocrinoidea, Blastozoa) is characterized by both a short stratigraphic range (Fezouata Shale, middle Tremadocian to middle Floian, Lower Ordovician) and a reduced geographic extension (Agdz-Zagora area, central Anti-Atlas, Morocco). Since the original description of its type...

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Bibliographic Details
Published inJournal of paleontology Vol. 91; no. 4; pp. 685 - 714
Main Authors Allaire, Ninon, Lefebvre, Bertrand, Nardin, Elise, Martin, Emmanuel L.O, Vaucher, Romain, Escarguel, Gilles
Format Journal Article
LanguageEnglish
Published New York, USA The Paleontological Society 01.07.2017
Cambridge University Press
Paleontological Society
SEPM Society for Sedimentary Geology
Subjects
Africa
Agdz Morocco
Animal morphology
Anti-Atlas
Area
Atlas Mountains
Biodiversity and Ecology
biometry
Blastozoa
cladistics
Crinozoa
Echinodermata
Environmental Sciences
Eocrinoidea
Fezouata Shale
Invertebrata
invertebrate
lithostratigraphy
Lower Ordovician
Marine invertebrates
Moroccan Atlas Mountains
Morocco
Morphology
Morphometry
North Africa
Ordovician
paleoecology
Paleontology
Paleozoic
phylogeny
revision
Rhopalocystidae
Rhopalocystis
Sedimentary rocks
Shale
Stratigraphy
taphonomy
Taxa
Taxonomic revision
taxonomy
Zagora Morocco
Zoology
Morocco
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Summary:The genus Rhopalocystis (Eocrinoidea, Blastozoa) is characterized by both a short stratigraphic range (Fezouata Shale, middle Tremadocian to middle Floian, Lower Ordovician) and a reduced geographic extension (Agdz-Zagora area, central Anti-Atlas, Morocco). Since the original description of its type species (R. destombesi Ubaghs, 1963), three successive revisions of the genus Rhopalocystis have led to the erection of nine additional species. The morphological disparity within this genus is here critically reassessed on the basis of both historical material and new recently collected samples. The detailed examination of all specimens, coupled with morphometric and cladistic analyses, points toward a relatively strong support for five morphotypes. A systematic revision of Rhopalocystis is thus suggested, with only five valid taxa: R. destombesi, R. fraga Chauvel, 1971, R. grandis Chauvel, 1971, R. havliceki Chauvel, 1978, and R. zagoraensis Chauvel, 1971. The five others are considered as junior synonyms (R. dehirensis Chauvel and Régnault, 1986, R. lehmani Chauvel and Régnault, 1986, R. sp. A, R. sp. B, and R. sp. C).
ISSN:0022-3360
1937-2337
DOI:10.1017/jpa.2017.6