Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-26T03:15:43.026Z Has data issue: false hasContentIssue false
  • English
  • Français

An Early Ordovician (Floian) asterozoan (Echinodermata) of problematic class-level affinities

Published online by Cambridge University Press:  28 October 2019

Daniel B. Blake Open the ORCID record for Daniel B. Blake [Opens in a new window] ,
Forest J. Gahn  and
Thomas E. Guensburg Open the ORCID record for Thomas E. Guensburg [Opens in a new window]
Daniel B. Blake
Affiliation:
Department of Geology, 3028 NHB, 1301 W Green St., Urbana, Illinois61801, USA
Forest J. Gahn
Affiliation:
Department of Geology, Brigham Young University—Idaho, Rexburg, Idaho83460-0510, USA
Thomas E. Guensburg
Affiliation:
IRC, The Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois60605, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

Falloaster anquiroisitus new genus new species (Asterozoa, Echinodermata) is described from the Floian (Early Ordovician) Garden City Formation of Idaho. The new taxon is known from a single small specimen. Because of weathering, remaining disk elements are incomplete. Dorsal surfaces of the ambulacral ossicles of two arms are available, one well preserved, whereas those of a third arm expose the ambulacrals essentially as they would appear in ventral view. Ambulacral ossicles were all but entirely lost on the remaining two arms.

Albeit asterozoan, F. anquiroisitus is not assignable at the class level. It is suggestive of the Asteroidea in presence of a domal disk, five abruptly tapering triangular, arched arms, and ambulacral ossicles vaulted to form a furrow. Ambulacral morphology, including the presence of very large podial pores, is unlike that of early asteroids. In addition, no adambulacral or other virgal-series derivatives are present; ambital framework ossicles are absent; a single series of enlarged, plate-like arm ossicles, one series on each side of the arm, come together at the arm midline; and the plate-like series were supported laterally by recurved ambulacral margins. Only remnants of the disk near the periphery survive, these of overall expression unlike any other echinoderm, including asterozoans. The mouth frame is unknown. Falloaster anquiroisitus is argued to represent an extinct lineage apart from the four recognized asterozoan classes, thereby joining a limited number of other problematic early Asterozoa.

UUID: http://zoobank.org/a13a5417-44b6-4ac3-90cf-9dc8fb5902bd

Type
Articles
Information
Journal of Paleontology , Volume 94 , Issue 2 , March 2020 , pp. 358 - 365
Copyright
Copyright © 2019, The Paleontological Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Adrain, J.M., McAdams, N.E.B., and Westrop, S.R., 2009, Trilobite biostratigraphy and revised bases of the Tulean and Blackhillsian Stages of the Ibexian Series, Lower Ordovician, western United States: Memoirs of the Association of Australian Palaeontologists, v. 37, p. 541–610.Google Scholar
Blake, D.B., 1995, A new asteroid genus from the Carboniferous of Ireland and its phylogenetic position and paleoecology: Irish Journal of Earth Sciences, v. 14, p. 65–80.Google Scholar
Blake, D.B., 2000, An Archegonaster-like somasteroid (Echinodermata) from Pomeroy, Co. Tyrone, Northern Ireland: Irish Journal of Earth Sciences, v. 18, p. 89–99.Google Scholar
Blake, D.B., 2013, Early asterozoan (Echinodermata) diversification: A paleontologic quandary: Journal of Paleontology, v. 87, p. 353–372.CrossRefGoogle Scholar
Blake, D.B., 2014, Two Ordovician asterozoans (Echinodermata) of problematic affinities: Journal of Paleontology, v. 88, p. 1163–1173.CrossRefGoogle Scholar
Blake, D.B., 2018, Toward a History of the Paleozoic Asteroidea (Echinodermata): Bulletins of American Paleontology 394, 96 p.Google Scholar
Blake, D.B., and Guensburg, T.E., 1989, Illusioluidia teneryi n. gen. and sp. (Asteroidea: Echinodermata) from the Pennsylvanian of Texas, and its homeomorphy with the extant genus Luidia Forbes: Journal of Paleontology, v. 63, p. 331–340.CrossRefGoogle Scholar
Blake, D.B., and Guensburg, T.E., 2015, The class Somasteroidea (Echinodermata, Asterozoa): Morphology and occurrence: Journal of Paleontology, v. 89, p. 465–486.CrossRefGoogle Scholar
Blake, D.B., Zamora, S., and García-Alcalde, J.L., 2015, A new Devonian asteroid-like ophiuroid from Spain: Geologica Acta, v. 13, p. 335–343.Google Scholar
Jaekel, O., 1923, Zur Morphogenie der Asterozoa: Palaeontologischen Zeitschrift, v. 5, p. 344–350.CrossRefGoogle Scholar
Mikulás, R., 1992, The ichnogenus Asteriacites: palenvironmental trends: Vestnik Ceského Geologického Ústavu, v. 67, p. 423–433.Google Scholar
Mooi, R., and David, B., 1998, Evolution within a bizarre phylum: Homologies of first echinoderms: American Zoologist, v. 38, p. 965–974.CrossRefGoogle Scholar
Mooi, R., and David, B., 2000, What a new model of skeletal homologies tells us about asteroid evolution: American Zoologist, v. 40, p. 326–339.Google Scholar
Mooi, R., and David, B., 2008, Radial symmetry, the anterior/posterior axis, and echinoderm Hox genes: Annual Review of Ecology, Evolution, and Systematics, v. 39, p. 43–62.CrossRefGoogle Scholar
Schöndorf, F., 1910, Über einige “Ophiuriden und Asteriden” des englischen Silur und ihre Bedeutung für die Systematik paläozoischer Seesterne: Jahrbüchern des Nassauischen Vereins für Naturkunde in Wiesbaden, v. 63, p. 206–256.Google Scholar
Schuchert, C., 1915, Revision of Paleozoic Stelleroidea with special reference to North American Asteroidea: Bulletin of the U.S. National Museum 88, 311 p.Google Scholar
Shackleton, J.D., 2005, Skeletal homologies, phylogeny and classification of the earliest asterozoan echinoderms: Journal of Systematic Palaeontology, v. 3, p. 29–114.CrossRefGoogle Scholar
Smith, A.B., and Jell, P.A., 1990, Cambrian edrioasteroids from Australia and the origin of starfishes: Memoirs of the Queensland Museum, v. 28, p. 715–778.Google Scholar
Spencer, W.K., 1914–1940, The British Palaeozoic Asterozoa: Palaeontographical Society of London Monograph, pts. 1–10 (for 1913–1940), 540 p.CrossRefGoogle Scholar
Spencer, W.K., 1951, Early Palaeozoic starfish: Philosophical Transactions of the Royal Society, London B, v. 235, p. 87–129.Google ScholarPubMed
Spencer, W.K., and Wright, C.W., 1966, Asterozoans, in Moore, R.C., ed., Treatise on Invertebrate Paleontology, part U, Echinodermata 3, Volume 1: Boulder, Colorado, and Lawrence, Kansas, The Geological Society of America and University of Kansas Press, p. U4–U107.Google Scholar
Thoral, M., 1935, Contribution à l’étude paléontologique de l'Ordovicien inférieur de la Montagne Noire et révision sommaire de la faune cambrienne de la Montagne Noire [Ph.D. thesis]: Paris, l'Université de Paris, 363 p.Google Scholar
Ubaghs, G., 1967, General characters of Echinodermata, in Moore, R.C., ed., Treatise on Invertebrate Paleontology, part S, Echinodermata 1, Volume 1: Boulder, Colorado, and Lawrence, Kansas, The Geological Society of America and University of Kansas Press, p. S3–S60.Google Scholar
Villier, L., Brayard, A., Bylund, K.G., Jenks, J.F., Escarguel, G., Loivier, N., Stephen, D.A., Vennin, E., and Fara, E., 2017, Superstesaster promissor gen. et sp. nov., a new starfish (Echinodermata, Asteroidea) from the Early Triassic of Utah, USA, filling a major gap in the phylogeny of asteroids: Journal of Systematic Palaeontology, v. 16, p. 395–415, https://doi.org/10.1080/14772019.2017.1308972.CrossRefGoogle Scholar
Zittel, K.A., 1895, Grundzüge der Palaeontologie (Palaeozoologie): Munich, R. Oldenbourg, 971 p.Google Scholar