Palaeocoma

Palaeocoma Temporal range: Ladinian-Toarcian ~242–182 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Palaeocoma milleri, Lower Jurassic (Pliensbachian) England.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Echinodermata
Class:	Ophiuroidea
Order:	Ophiurida
Family:	incertae sedis
Genus:	†Palaeocoma d'Orbigny, 1850[1]
Species
Palaeocoma escheri Palaeocoma milleri Palaeocoma raiblana

Palaeocoma is an extinct genus of brittle stars that lived during the Middle Triassic to Early Jurassic Periods. Its fossils have been found in Europe.[2]

Distribution

The genus Palaeocoma was revised by Hess (1960, 1962)[3][4] and is known from the Middle Triassic (Ladinian) to the Lower Jurassic (Toarcian) with occurrences reported from the United Kingdom,[5][6] France,[7][8] Luxembourg,[9] Germany,[10] Switzerland,[3][4] Italy,[11] and Serbia and Montenegro.[12]

Type species

Palaeocoma milleri (Phillips, 1829)[13] [= P. gaveyi and P. egertoni according to Jaselli (2015, p. 192)], an Early Jurassic (Sinemurian and Pliensbachian) species recorded from France, Germany, Luxembourg, the United Kingdom and Lombardy in Italy.[14]

Synonymised names

Ophioderma carinata Wright, 1866[15]

Ophioderma egertoni (Broderip, 1840)[16]

Ophioderma gaveyi Wright, 1854[17]

Ophioderma milleri (Phillips, 1829)

Ophiura egertoni Broderip, 1840

Ophiura milleri Phillips, 1829

Ophiurella milleri (Phillips, 1829)

Palaeocoma egertoni (Broderip, 1840)

Palaeocoma gaveyi (Wright, 1854)

Other species

• Palaeocoma escheri Herr, 1865[18] [= Ophiura ventrocarinata Quenstedt 1876][19] was redescribed by Hess (1960) and is from the Lower Lias Staffelegg Formation,[20] of Schambelen near Mülligen in the Canton of Aargau of northern Switzerland. It occurs in the Hettangian, the earliest age and lowest stage of the Jurassic period and, specifically, the Psiloceras planorbis Ammonite Zone.
• Palaeocoma raiblana (Toula, 1887).[21] This species is only found in the Triassic Wengener Schichten Formation (Ladinian) of Budva in Serbia and Montenegro).

Gallery

• 
  Palaeocoma milleri from the famous 'Starfish Bed' at Eype, UK. Coin diameter = 23.4mm.
• 
  Palaeocoma milleri

References

1. Orbigny A. D. d'. (1850-1852). Prodrome de paléontologie stratigraphique universelle des animaux mollusques et rayonnés faisant suite au cours élémentaire de paléontologie et de géologie stratigraphiques. Paris: Masson. vol. 1 [January 1850 ("1849")]: lx + 394 pp.; vol. 2 [November 1850]: 427 pp.; vol. 3 [1852]: 389 pp.
2. Cyril Walker, David Ward Fossils : Smithsonian Handbook, ISBN 0-7894-8984-8 (2002, paperback, revisited), ISBN 1-56458-074-1 (1992, 1st edition). Page 189.
3. Hess, H. (1960). "Ophioderma escheri Heer aus dem unteren Lias der Schambelen (Kt. Aargau) und verwandete Lias-Ophiuren aus England und Deutschland". Eclogae Geologicae Helvetiae (in German). 53: 757–793.
4. Hess, H. (1962). "Mikropaläontologische Untersuchungen an Ophiuren II. Die Ophiuren aus dem Lias (Pliensbachien-Toarcien) von Seewen (Kt. Solothurn)". Bericht der Schweitzerischen Palaeontologischen Gesellschaft. 55: 609–656.
5. Hess, H. (1964). "Die Ophiuren des englischen Jura". Eclogae Geologicae Helvetiae. 57: 755–821.
6. Kutscher, M. (1996). "Echinodermata aus dem Ober-Toarcium und Aalenium Deutschlands II: Ophiuroidea". Stuttgarter Beiträge zur Naturkunde, Serie B (Geologie und Paläontologie). 242: 1–33.
7. Thuy, B. (2011). "Exceptionally well-preserved brittle stars from the Pliensbachian (Early Jurassic) of the French Ardennes". Palaeontology. 54 (1): 215–233. Bibcode:2011Palgy..54..215T. doi:10.1111/j.1475-4983.2010.00981.x. S2CID 140581836.
8. Thuy, B.; Gale, A.S.; Reich, M. (2011). "A new echinoderm Lagerstätte from the Pliensbachian (Early Jurassic) of the French Ardennes". Swiss Journal of Palaeontology. 130 (1): 173–185. Bibcode:2011SwJP..130..173T. doi:10.1007/s13358-010-0015-y.
9. Kutscher, M.; Hary, A. (1991). "Echinodermen im Unteren Lias (bucklandi-und semicostatum-zone) zwischen Ellange und Elvange (SE-Luxemburg)". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 182: 37–72. doi:10.1127/njgpa/182/1991/37.
10. Kutscher, M. (1988). "Zur Invertebratenfauna und Stratigraphie desoberen Pliensbachien von Grimmen (DDR), Echinodermata". Freiberger Forschungsheft, C. 419: 62–70.
11. Pinna, G. (1985). "Exceptional preservation in the Jurassic of Osteno". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 311 (1148): 171–180. Bibcode:1985RSPTB.311..171P. doi:10.1098/rstb.1985.0149.
12. Bachmayer, F.; Kollmann, H.A. (1968). "Ein Ophiure aus der Trias Jugoslawiens". Annalen des Naturhistorischen Museums in Wien. 72: 645–648.
13. Phillips J. (1829). Illustrations of the Geology of Yorkshire; or a description of the strata and organic remains of the Yorkshire Coast. Part 1. 192 pp. York.
14. Jaselli, L., 2015. The Lower Jurassic (Early Sinemurian) ophiuroid Palaeocoma milleri in the palaeontological collection of the Museo di Storia Naturale “Antonio Stoppani” (Italy). Bollettino della Società Paleontologica Italiana, 54 (3), 187-195. Modena.
15. Wright, T. (1866). A monograph on the British fossil Echinodermata from the Oolitic formations. 2/2 On the Ophiuroidea. Paleontologr. Society London.
16. Broderip, W. J. (1840). "Description of some fossil Crustacea and Radiata, found at Lyme Regis, in Dorsetshire". Transactions of the Geological Society of London. 2: 390–396.
17. Wright, T. (1854). "Contributions to the Palaeontology of Gloucestershire: a description, with figures of some new species of Echinodermata from the Lias and Oolites". The Annals and Magazine of Natural History. 2 (13): 376–383.
18. Herr, O. (1865). Die Urwelt der Schweiz. 1. 622 pp. Schulthess, Zürich.
19. Quenstedt, F. A. 1876. Petrefactenkunde Deutschlands: Erste Abtheilung, Vierter (4) Band, Echinodermen (Asteriden und Encriniden). 742 pp. Fues Verlag, Leipzig.
20. Reisdorf A. G., Wetzel, A., Schlatter, R., Jordan, P. 2011. The Staffelegg Formation: a new stratigraphic schemefor the Early Jurassic of northern Switzerland. Swiss J Geosci 104: 97 – 146.
21. Toula, F. (1887). Über Aspidura raiblana nov. spec. Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften, 96, 361-369.