Ophiactis savignyi Lineage B

Invasion History

First Non-native Panama (Caribbean) Tidal Record: 2002

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Panama Invasion History:

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Invasion history elsewhere in the world:

Ophiactis savignyi is considered a recent invader in the Mediterranean, which it apparently colonized through the Suez Canal, reaching Israel by 1948 (Galil 2007). In the Mediterranean, it is known from the Aegean Sea (in 1994, Pancucci-Papadopoulou et al. 2005), and the Gulf of Gabes, Tunisia (in 1973, United States Museum of Natural History 2008). One specimen was found in Banyuls-sur-Mer, France (in 1968, Guile 1968). It also occurs in the East Atlantic on Madeira (Jesus and Domingos 1998) and Senegal (United States National Museum of Natural History 2011).

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Description

Ophiactis savignyi has a disk diameter of 2.5 - 5 mm, usually with six arms 13-20 mm in length. This brittle star reproduces by fission, and can regenerate lost arms, so numbers of arms can vary from 1-7. Small spines are scattered over the disk surface. On the ventral side of the disk, three scale-like oral papillae are present around the mouth, and the oral shields are large. On the dorsal side of the disk, the radial shields are large. The aboral arm plates are elliptical with rounded lateral margins, and a convex distal edge with a median lobe made prominent by a dark spot on either side. There are 5-6 arm spines on each arm segment. Body color ranges from brown to brown-green and cream. The radial shields are darker than the rest of the disk and generally have a patch of white along the outer tip. The arms are banded due to the dark markings on distal portions of the arm plates (Smithsonian Marine Station 2011; Stöhr 2011).

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Taxonomy

Ecology

General:

Ophiactis savignyi is a brittle star which reproduces sexually, broadcasting eggs and sperm, but it can also reproduce asexually by fission. Animals inhabiting sponges tend to be of one sex, dominated by immature animals, and appear to be dependent on asexual reproduction. There appears to be a trade-off between sexual and asexual reproduction, with asexual reproduction being more likely in populations with a lower probability of fertilization. Males are more likely to divide than females, which are more likely to lose their gonads after fission, resulting in a skewed sex ratio (McGovern 2002; McGovern 2003). Ophiactis savignyi can be found in a variety of habitats including rocky shores and seaweed beds, the interior of sponges, mangroves, corals, docks, and boat hulls (Roy and Sponer 2002; McGovern 2003).

Food:

detritus, foraminfera, benthic invertebrates

Trophic Status:

Deposit Feeder

DepFed

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Habitats

General Habitat	Coral reef	None
General Habitat	Grass Bed	None
General Habitat	Marinas & Docks	None
General Habitat	Vessel Hull	None
General Habitat	Rocky	None
General Habitat	Unstructured Bottom	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Vertical Habitat	Epibenthic	None

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Tolerances and Life History Parameters

Maximum Duration	30	Larval duration, approximate, Roy and Sponer 2002
Minimum Length (mm)	28.5	Adult radius (disk + arms)
Maximum Length (mm)	45	Adult radius (disk + arms)
Broad Temperature Range	None	Warm temperate-Tropical
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

No direct impacts have been reported for this species, but they could be substantial, given the high abundance of this brittle star in some locations.

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References

Amor, Kounofi-Ben; Rifi, M.; Ghanem, R.; Draief, I.; Zouali, J.; Souissi, J. Ben (2016) Update of alien fauna and new records of Tunisian marine fauna, Mediterranean Marine Science 17(1): 124-143

Barboza, Carlos Alberto de Moura; Mattos, Gustavo; Paiva, Paulo Cesar (2015) Brittle stars from the Saint Peter and Saint Paul Archipelago: morphological and molecular data, Marine Biodiversity Records 8: e16

Boffi, E. (1972) Ecological aspects of ophiuroids from the phytal of S. W. Atlantic Ocean warm waters., Marine Biology 15: 316--328

California Academy of Sciences 2005-2015 Invertebrate Zoology Collection Database. <missing URL>



Chung, W. K.; King, Gary M. (1999) Biogeochemical transformations and potential polyaromatic hydrocarbon degradation in macrofaunal burrow sediments, Aquatic Microbial Ecology 19: 285-295

Çinar, Melih Ertan and 7 authors (2021) Current status (as of end of 2020) of marine alien species in Turkey, PLOS ONE 16: Published online

de Jesus, Dora Cunha; Abreu, Antonio Domingos (1998) Contribution to the knowledge of the soft bottom echinoderms of Madeira Island, Boletim do Museu Municipal do Funchal 50: 59-69

Galil, Bella S. (2007) Seeing Red: Alien species along the Mediterranean coast of Israel., Aquatic Invasions 2(4): 281-312

Guille, Alain (1968) Sur la presence de Ophiactis savgnyi Muller and Troschel dans la region de Banyls-sur-Mer., Vie et Milieu Serie A: Biologie Marine 19(2A): 497-500

Hendler, Gordon; Baldwin, Carole C.; Smith, David G.; Thacker, Christine E. (1999) Planktonic dispersal of juvenile brittle stars (Echinodermata: Ophiuroidea) on a Caribbean reef., Bulletin of Marine Science 65(1): 283-288

Hendler, Gordon; Brugneaux, Sophie J. (2013) New records of brittle stars from French Guiana: Ophiactis savignyi and the alien species Ophiothela mirabilis (Echinodermata: Ophiuroidea), Marine Biodiversity Records 6: e113

Katsanevakis, S.; Tsiamis, K.; Ioannou, G.; Michailidis, N.; Zenetos, A. (2009) Inventory of alien marine species of Cyprus, Mediterranean Marine Science 10(2): 109-133

Lima, Maria Lilian F; Correia, Monica D.; Sovierzoski, Hilda H.; Cynthia L. C. Manso (2011) New records of Ophiuroidea (Echinodermata) from shallow waters off Maceio, State of Alagoas, Brazil, Marine Biodiversity Records 4: 1-10

McGovern, Tamara M. (2002) Sex-ratio bias and clonal reproduction in the brittle star Ophiactis savignyi., Evolution 56(3): 511-517

McGovern, Tamara M. (2003) Plastic reproductive strategies in a clonal marine invertebrate., Proceedings of the Royal Society B. Biological Sciences. 270(1532): 2517-2522

Mead, A.; Carlton, J. T.; Griffiths, C. L. Rius, M. (2011b) Introduced and cryptogenic marine and estuarine species of South Africa, Journal of Natural History 39-40: 2463-2524

Pancuci-Papadopoulou., M. A.; Zenetos, A , Corsini-Foka; Politou, Ch. (2005) Update of marine alien species in Hellenic waters., Mediterranean Marine Science 6(2): 1-11

Roy, M. S.; Sponer, R. (2002) Evidence of a human-mediated invasion of the tropical western Atlantic by the world's most common brittlestar., Proceedings of the Royal Society of London. Series B 269: 1017-1023

Smithsonian Marine Station at Fort Pierce 2011 Field Guide to the Indian River Lagoon. <missing URL>



Stöhr, Sabine (Ed.) 2011 World Ophiuroidea Database. <missing URL>



U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database. http://collections.nmnh.si.edu/search/iz/



United States National Museum of Natural History 2004 Flora of the Washington-Baltimore Area. <missing URL>



Zibrowius, Helmut (2002) Assessing scale and impact of ship-transported alien fauna in the Mediterranean?, CIESM Workshop Monographs 20: 63-68

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