Abstract
Identifiable remains of large deep-sea invertebrates are exceedingly rare in the fossil record. Thus, every new discovery adds to a better understanding of ancient deep-sea environments based on direct fossil evidence. Here we describe a collection of dissociated skeletal parts of ophiuroids (brittle stars) from the latest Pliocene to earliest Pleistocene of Sicily, Italy, preserved as microfossils in sediments deposited at shallow bathyal depths. The material belongs to a previously unknown species of ophiacanthid brittle star, Ophiacantha oceani sp. nov. On the basis of morphological comparison of skeletal microstructures, in particular spine articulations and vertebral articular structures of the lateral arm plates, we conclude that the new species shares closest ties with Ophiacantha stellata, a recent species living in the present-day Caribbean at bathyal depths. Since colonization of the deep Mediterranean following the Messinian crisis at the end of the Miocene was only possibly via the Gibraltar Sill, the presence of tropical western Atlantic clades in the Plio-Pleistocene of the Mediterranean suggests a major deep-sea faunal turnover yet to be explored.
References
Borghi, E., Garilli, V. & Bonomo, S. (2014) Plio-Pleistocene Mediterranean bathyal echinoids: evidence of adaptation to psychrospheric conditions and affinities with Atlantic assemblages. Palaeontologia Electronica, 17.3.44A, 1–26.
https://doi.org/10.26879/476
Bribiesca-Contreras, G., Verbruggen, H., Hugall, A.F. & O’Hara, T.D. (2017) The importance of offshore origination revealed through ophiuroid phylogenomics. Proceedings of the Royal Society B, 284, 20170160.
https://doi.org/10.1098/rspb.2017.0160
Cita, M.B. (1975) Studi sul Pliocene e gli strati di passaggio dal Miocene al Pliocene. VII. Planktonic foraminiferal biozonation of the Mediterranean Pliocene deep-sea record. A revision. Rivista Italiana di Paleontologia e Stratigrafia, 81 (4), 527–544.
Danovaro, R., Company, J.B., Corinaldesi, C., D’Onghia, G., Galil, B., Gambi, C., Gooday, A.J., Lampadariou, N., Luna, G.M., Morigi, C., Olu, K., Polymenakou, P., Ramirez-Llodra, E., Sabbatini, A., Sardà, F., Sibuet, M. & Tselepides, A. (2010) Deep-Sea Biodiversity in the Mediterranean Sea: The Known, the Unknown, and the Unknowable. PLoS ONE, 5 (8), e11832.
https://doi.org/10.1371/journal.pone.0011832
Di Geronimo, I. & La Perna, R. (1997) Homalopoma emulum (SEGUENZA, 1876), a bathyal cold-stenothermic gastropod in the Mediterranean Pleistocene. Geobios, 30 (3), 215–223.
https://doi.org/10.1016/S0016-6995(97)80227-6
Emig, C.C. & Geistdoerfer, P. (2004) The Mediterranean deep-sea fauna: historical evolution, bathymetric variations and geographical changes. Carnets de Géologie/Notebooks on Geology, Maintenon, Art.2004/01, CG2004-A01-CCE-PG.
https://doi.org/10.4267/2042/3230
Etter, W. & Hess, H. (2015) Reviews and syntheses: the first records of deep-sea fauna – a correction and discussion. Biogeosciences, 12, 6453–6462.
https://doi.org/10.5194/bg-12-6453-2015
Fois, E. (1990) Stratigraphy and palaeogeography of the Capo Milazzo area (NE Sicily, Italy): clues to the evolution of the southern margin of the Tyrrhenian Basin during the Neogene. Palaeogeography, Palaeoclimatology, Palaeoecology, 78, 87–108.
https://doi.org/10.1016/0031-0182(90)90206-M
Forbes, E. (1852) Monograph of the Echinodermata of the British Tertiaries. Palaeontographical Society London, 6, 1–36.
https://doi.org/10.1080/02693445.1852.12023333
Gaetani, M. & Saccà, D. (1984) Brachiopodi batiali nel Pliocene e Pleistocene di Sicilia e Calabria. Rivista Italiana di Paleontologia e Stratigrafia, 90, 407–458.
Gray, J.E. (1840) Room II. In: Synopsis of the contents of the British Museum. British Museum, London, pp. 57–65.
Harzhauser, M., Kroh, A., Mandic, O., Piller, W.E., Göhlich, U., Reuter, M. & Berning, B. (2007) Biogeographic responses to geodynamics: a key study all around the Oligo-Miocene Tethyan Seaway. Zoologischer Anzeiger, 246, 241–256.
https://doi.org/10.1016/j.jcz.2007.05.001
Hess, H. (1962) Mikropaläontologische Untersuchungen an Ophiuren: I. Einleitung. Eclogae Geologicae Helvetiae, 55, 595–608.
Hsü, K.J., Ryan, W.B.F. & Cita, M.B. (1973) Late Miocene desiccation of the Mediterranean. Nature, 242, 240–244.
https://doi.org/10.1038/242240a0
Ljungman, A.V. (1867) Ophiuroidea viventia huc usque cognita. Öfversigt af Kungliga Vetenskaps-Akademiens Förhandlingar 1866, 23, 303–336.
Lütken, C.F. (1869) Additamenta ad historiam Ophiuridarum. Tredie Afdelning. Det kongelige danske Videnskabernes Selskabs Skrifter. 5 Raekke, Naturvidenskabelig og mathematisk Afdelning, 8, 20–109.
Lyman, T. (1875) Zoological Results of the Hassler Expedition. 2. Ophiuridae and Astrophytidae. Illustrated catalogue of the Museum of Comparative Zoology at Harvard College, 8 (2), 1–34, 5 pls.
Lyman, T. (1878) Ophiuridae and Astrophytidae of the “Challenger” expedition. Part I. Bulletin of the Museum of Comparative Zoology at Harvard College, Cambridge, Massachusetts, 5 (7), 65–168, 10 pls.
Lyman, T. (1879) Ophiuridae and Astrophytidae of the “Challenger” expedition. Part II. Bulletin of the Museum of Comparative Zoology at Harvard College, Cambridge, Massachusetts, 6 (2), 17–83, 10 pls.
Marsili, S. (2007) A new bathyal shark fauna from the Pleistocene sediments of Fiumefreddo (Sicily, Italy). Geodiversitas, 29 (2), 229–247.
Martynov, A.V. (2010) Reassessment of the classification of the Ophiuroidea (Echinodermata), based on morphological characters. I. General character evaluation and delineation of the families Ophiomyxidae and Ophiacanthidae. Zootaxa, 2697 (1), 1–154.
https://doi.org/10.11646/zootaxa.2697.1.1
Matsumoto, H. (1915) A new classification of the Ophiuroidea: with descriptions of new genera and species. Proceedings of the Academy of Natural Sciences, Philadelphia, 67, 43–92.
Mecho, A., Billett, D.S.M., Ramírez-Llodra, E., Aguzzi, J., Tyler, P.A. & Company, J.B. (2014) First records, rediscovery and compilation of deep-sea echinoderms in the middle and lower continental slope of the Mediterranean Sea. Scientia Marina, 78 (2), 281–302.
https://doi.org/10.3989/scimar.03983.30C
Müller, J.H. & Troschel, F.H. (1842) System der Asteriden. Vieweg & Sohn, Braunschweig.
O’Hara, T.D., Hugall, A.F., Thuy, B. & Moussalli, A. (2014) Phylogenomic resolution of the class Ophiuroidea unlocks a global microfossil record. Current Biology, 24, 1874–1879.
https://doi.org/10.1016/j.cub.2014.06.060
O’Hara, T.D., Hugall, A.F., Thuy, B., Stöhr, S. & Martynov, A.V. (2017) Restructuring higher taxonomyusing broad-scale phylogenomics: The living Ophiuroidea. Molecular Phylogenetics and Evolution, 107, 415–430.
https://doi.org/10.1016/j.ympev.2016.12.006
O’Hara, T.D. & Stöhr, S. (2006) Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae In: Richer de Forges, B & Justine, J.-L. (Eds.), Tropical Deep-Sea Benthos. Vol. 24. Mémoires du Muséum national d’Histoire naturelle, 193, pp. 33–141.
O’Hara, T.D., Stöhr, S., Hugall, A.F., Thuy, B. & Martynov, A. (2018) Morphological diagnoses of higher taxa in ophiuroidea (Echinodermata) in support of a new classification. European Journal of Taxonomy, 416, 1–35.
https://doi.org/10.5852/ejt.2018.416
Paterson, G.L.J. (1985) The deep-sea Ophiuroidea of the north Atlantic Ocean. Bulletin of the British Museum (Natural History) Zoology, 49 (1), 1–162.
Pawson, D.L., Vance, D.J., Messing, C.G., Solis-Marin, F.A. & Mah, C.L. (2009) Echinodermata of the Gulf of Mexico. In: Felder, D.L. & Camp, D.K. (Eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College S., pp. 1177–1204.
Reich, M. & Kutscher, M. (2001) Ophiocistioids and holothurians from the Silurian of Gotland (Sweden). In: Baker, M. (Ed.), Echinoderms 2000. Proceedings of the 10th International Echinoderm Conference, Dunedin, 31 January–4 February 2000. A. A. Balkema, Lisse, pp. 97–101.
Roux, M., Barrier, P., Di Geronimo, I. & Montenat, C. (1988) Découverte de crinoïdes pédonculés bathyaux d’origine atlantique dans le Pliocène supérieur et le Pléistocène moyen méditerranéen : conséquences biogéographiques. Comptes rendus de l’Académie des Sciences, Paris, 307, 259–264.
Sars, G.O. (1872) Nye Echinodermer fra den norske kyst. Forhandlinger i Videnskabs-selskabet i Christiania, 1871, 1–31.
Smith, A.B. & Stockley, B. (2005) The geological history of deep-sea colonization by echinoids: roles of surface productivity and deep-water ventilation. Proceedings of the Royal Society B, 272, 865–869.
https://doi.org/10.1098/rspb.2004.2996
Stöhr, S., O’Hara, T.D. & Thuy, B. (2012) Global Diversity of Brittle Stars (Echinodermata: Ophiuroidea). PLoS ONE, 7 (3), e31940.
https://doi.org/10.1371/journal.pone.0031940
Stöhr, S., O’Hara, T.D. & Thuy, B. (Eds.) (2018) World Ophiuroidea database. Ophiacantha Müller & Troschel, 1842. Accessed through: World Register of Marine Species. Available from: http://www.marinespecies.org/aphia.php?p=taxdetails&id=123587 (accessed 2 October 2018)
Thuy, B. (2013) Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea). European Journal of Taxonomy, 48, 1–242.
https://doi.org/10.5852/ejt.2013.48
Thuy, B., Gale, A.S., Kroh, A., Kucera, M., Numberger-Thuy, L.D., Reich, M. & Stöhr, S. (2012) Ancient Origin of the Modern Deep-Sea Fauna. PLoS ONE, 7 (10), e46913.
https://doi.org/10.1371/journal.pone.0046913
Thuy, B. & Stöhr, S. (2011) Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification. Zootaxa, 3013 (1), 1–47.
https://doi.org/10.11646/zootaxa.3013.1.1
Thuy, B. & Stöhr, S. (2016) A new morphological phylogeny of the Ophiuroidea (Echinodermata) accords with molecular evidence and renders microfossils accessible for cladistics. PLoS One, 11 (5), e0156140.
https://doi.org/10.1371/journal.pone.0156140
Thuy, B. & Stöhr, S. (2018) Unravelling the origin of the basket stars and their allies (Echinodermata, Ophiuroidea, Euryalida). Scientific Reports, 8, 8493.
https://doi.org/10.1038/s41598-018-26877-5
Violanti, D. (1988) I foraminiferi plio-pleistocenici di Capo Milazzo. Bollettino del Museo Regionale di Scienze Naturali di Torino, 6, 359–392.
Woolley, S.N.C., Tittensor, D.P., Dunstan, P.K., Guillera-Arroita, G., Lahoz-Monfort, J.J., Wintle, B.A., Worm, B. & O’Hara, T.D. (2016) Deep-sea diversity patterns are shaped by energy availability. Nature, 533, 393–396.
https://doi.org/10.1038/nature17937