First report of a nearly complete comatulid crinoid (Comatulida, Echinodermata) from the Cretaceous of Australia

Abstract Finds of stalkless comatulid crinoids in the Southern Hemisphere are extremely rare and are almost exclusively of their centrodorsals. Complete or nearly complete specimens (centrodorsal with articulated arms, cirri and/or pinnules) are known from only a few localities. Here we report a com...

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Main Authors: Mariusz A. Salamon, Tamas Kapitany, Bartosz J. Płachno
Format: Article
Language:English
Published: Nature Portfolio 2025-03-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-025-90111-2
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author Mariusz A. Salamon
Tamas Kapitany
Bartosz J. Płachno
author_facet Mariusz A. Salamon
Tamas Kapitany
Bartosz J. Płachno
author_sort Mariusz A. Salamon
collection DOAJ
description Abstract Finds of stalkless comatulid crinoids in the Southern Hemisphere are extremely rare and are almost exclusively of their centrodorsals. Complete or nearly complete specimens (centrodorsal with articulated arms, cirri and/or pinnules) are known from only a few localities. Here we report a comatulid fossil comprised of a centrodorsal, arms, and pinnules, assigned to Solanocrinitidae gen. et sp. indet. The shape of the centrodorsal; the arrangement, shape, and size of radials; and the morphology of the radial cavity suggest similarity of this fossil to Solanocrinites or Archaeometra rather than to Comatulina, Pachyantedon, or Palaeocomaster. It cannot be ruled out that the studied specimen belongs to Decameros with its relatively low and discoidal centrodorsal. In the light of last phylogenetic analysis both Solanocrinites and Decameros were recovered as part of a clade comprising Himerometroidea, Tropiometridae, and Asterometridae + Ptilometridae. The preserved arms of the Australian specimen reveals variation in the branching pattern, that can be attributed to the inaccurate regeneration of arms after autotomy. This find represents the second articulated comatulid (except of uintacrinids) which consists not only of the centrodorsal, but also having more or less complete arms and pinnules, from the Cretaceous of the Southern Hemisphere. It is also the first found from Australia. The only opalized crinoid known in the world is the stalked isocrinid (Isocrinida) Isocrinus australis. Thus, the present find is also the first record of an opalized comatulid crinoid worldwide. Additionally, the thin sections reveal the occurrence of transversal sections of pelagic roveacrinids (saccocomids), which are also the first from the Australian continent.
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spelling doaj-art-db38e25a47ca4a828ac9904ab84914b82025-08-20T03:01:23ZengNature PortfolioScientific Reports2045-23222025-03-0115111110.1038/s41598-025-90111-2First report of a nearly complete comatulid crinoid (Comatulida, Echinodermata) from the Cretaceous of AustraliaMariusz A. Salamon0Tamas Kapitany1Bartosz J. Płachno2Faculty of Natural Sciences, Institute of Earth Sciences, Laboratory of Palaeontology and Stratigraphy, University of Silesia in KatowiceNational Dinosaur MuseumFaculty of Biology, Institute of Botany, Department of Plant Cytology and Embryology, Jagiellonian University in KrakówAbstract Finds of stalkless comatulid crinoids in the Southern Hemisphere are extremely rare and are almost exclusively of their centrodorsals. Complete or nearly complete specimens (centrodorsal with articulated arms, cirri and/or pinnules) are known from only a few localities. Here we report a comatulid fossil comprised of a centrodorsal, arms, and pinnules, assigned to Solanocrinitidae gen. et sp. indet. The shape of the centrodorsal; the arrangement, shape, and size of radials; and the morphology of the radial cavity suggest similarity of this fossil to Solanocrinites or Archaeometra rather than to Comatulina, Pachyantedon, or Palaeocomaster. It cannot be ruled out that the studied specimen belongs to Decameros with its relatively low and discoidal centrodorsal. In the light of last phylogenetic analysis both Solanocrinites and Decameros were recovered as part of a clade comprising Himerometroidea, Tropiometridae, and Asterometridae + Ptilometridae. The preserved arms of the Australian specimen reveals variation in the branching pattern, that can be attributed to the inaccurate regeneration of arms after autotomy. This find represents the second articulated comatulid (except of uintacrinids) which consists not only of the centrodorsal, but also having more or less complete arms and pinnules, from the Cretaceous of the Southern Hemisphere. It is also the first found from Australia. The only opalized crinoid known in the world is the stalked isocrinid (Isocrinida) Isocrinus australis. Thus, the present find is also the first record of an opalized comatulid crinoid worldwide. Additionally, the thin sections reveal the occurrence of transversal sections of pelagic roveacrinids (saccocomids), which are also the first from the Australian continent.https://doi.org/10.1038/s41598-025-90111-2
spellingShingle Mariusz A. Salamon
Tamas Kapitany
Bartosz J. Płachno
First report of a nearly complete comatulid crinoid (Comatulida, Echinodermata) from the Cretaceous of Australia
Scientific Reports
title First report of a nearly complete comatulid crinoid (Comatulida, Echinodermata) from the Cretaceous of Australia
title_full First report of a nearly complete comatulid crinoid (Comatulida, Echinodermata) from the Cretaceous of Australia
title_fullStr First report of a nearly complete comatulid crinoid (Comatulida, Echinodermata) from the Cretaceous of Australia
title_full_unstemmed First report of a nearly complete comatulid crinoid (Comatulida, Echinodermata) from the Cretaceous of Australia
title_short First report of a nearly complete comatulid crinoid (Comatulida, Echinodermata) from the Cretaceous of Australia
title_sort first report of a nearly complete comatulid crinoid comatulida echinodermata from the cretaceous of australia
url https://doi.org/10.1038/s41598-025-90111-2
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AT tamaskapitany firstreportofanearlycompletecomatulidcrinoidcomatulidaechinodermatafromthecretaceousofaustralia
AT bartoszjpłachno firstreportofanearlycompletecomatulidcrinoidcomatulidaechinodermatafromthecretaceousofaustralia