A cladid-dominated early Mississippian crinoid and conodont fauna from Kerman Province, Iran and revision of the glossocrinids and rhenocrinids

G. D. Webster*, C. G. Maples, R. Mawson, M. Dastanpour

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    16 Citations (Scopus)

    Abstract

    A moderately diverse crinoid fauna from the Early Mississippian, Tournaisian, part of the Bahram Formation is reported from exposures in the vicinities of Hutk and Shams Abad, north of Kerman in southeastern Iran. Conodonts from the crinoid-bearing beds represent two faunas and indicate an age of Upper Siphonodella crenulata Biozone to Gnathodus typicus Biozone. Recognition of a Tournaisian age for this part of the Bahram Formation revises the previously assigned Famennian age and indicates that Famennian strata are much thinner, if present, in southeastern Iran. The fauna occurs in thin-bedded marls and limestones at the top of a shaley slope-forming sequence that grades upward into resistant cliff-forming limestones. Most crinoid specimens are crowns (many retaining part of the proximal stem) that have been flattened by compaction. At the genus level the crinoids include five camerates, three cladid dendrocrinids, ten other cladids, three flexibles, and one articulate. In addition, loose arm fragments and occasional cup fragments are common, along with abundant pluricolumnals and columnals in the fauna. Dominance of cladids over camerates probably reflects the argillaceous sediment in the mixed carbonate/siliciclastic platform environment of the fauna. This is the most diverse Tournaisian fauna reported from the northern margin of Gondwana and represents an equatorial fauna living at approximately 20°S latitude. Stronger affinities are with North American and European crinoid faunas than with Chinese and Australian faunas. Shallow-shelf conodonts from the crinoid-bearing beds are dominated by species of Polygnathus. Palaeoniscoid fish remains and shark teeth from the same beds support a shallow-shelf environment. New taxa proposed are Dichocrinus shamsensis new species; D. labyrinthus new species; Springeracrocrinus conicus new species; Atelestocrinus hutkensis new species; Zangucrinus abadensis new genus and species; Glossocrinacea new superfamily; Gelasinocrinus revimentus new genus and species; Amabilicrinidae new family; Amabilicrinus iranensis new genus and species, A. bahramensis new species; Derorhethocrinus elongatus new genus and species; Corematocrinidae new family; Lorocrinus zanguensis new genus and species; Blothrocrinus yazdii new species; Culmicrinus cylindratus new species; Paracosmetocrinus delicatus new species; Taxocrinus quadribrachiatus new species; Meristocrinus ovatus new species; and Hutkocrinus kermanensis new genus and species. Revision of the Glossocrinidae also resulted in designation of two new genera not present in the Iranian fauna: Bufalocrinus new genus (type species Catactocrinus? torus Webster and Hafley, 1999, from the Late Devonian, Famennian, of Colorado) and Nudalocrinus new genus (type species Culmicrinus jeffersonensis Laudon and Severson, 1953, from the Tournaisian of Montana).

    Original languageEnglish
    Pages (from-to)1-35
    Number of pages35
    JournalJournal of Paleontology
    Volume77
    Issue number3 SUPPL.
    Publication statusPublished - May 2003

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