Redekea californica

Invasion History

First Non-native North American Tidal Record: 1953
First Non-native West Coast Tidal Record: 1953
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Redekea californica is a commensal on the gribble Limnoria tripunctata (Carlton 1979). It was first described from San Diego Bay, California, where L. tripunctata is an introduced species, and therefore is also presumed to be introduced (Carlton 1979). We are not aware of any records of R. californica from other parts of the world. The native region of R. californica is unknown.

North American Invasion History:

Invasion History on the West Coast:

Redekea californica was first described from specimens found among the marine isopod Limnoria tripunctata on pilings at the U.S. Naval Target Repair Base, San Diego, California, on Dec. 14, 1953. Seventeen specimens are preserved at the Zoological Museum, Amsterdam (de Vos and Stock 1956). We know of no other collections of this ostracod, but we presume that the species is still established.

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Description

The body of an ostracod is enclosed by a bivalve carapace, with two calcified lateral shells connected by a dorsal band of un-calcified cuticle. The shell can be closed by bundles of transverse muscle fibers (central adductor muscles) near the center of each valve, or opened to permit the appendages to extend for crawling or feeding. The surface of the shell has numerous openings for pore canals, equipped with chemosensory and tactile sensilla, and may be ornamented with pits, tubercles, and irregular projections.

In the order Podocopa, to which Redekea californica belongs, there is no rostrum and no antennal notch in the anterior margin of the valves. Antenna 1 is uniramous. Antenna 2 has the exopodite reduced to a long, thin, 4-jointed rod. There are 7 pairs of limbs: Antenna 1, Antenna 2, Mandible, Maxilla, and 3 pairs of walking legs or pereiopods (Barnes 1983; Cohen et al. 2007). The body terminates in a greatly reduced furca, posterior to the anus, and ending in prominent claws (Barnes 1983; Cohen et al. 2007).

Redekea californica has a comparatively thin, compressed, elongated kidney-shaped shell, with its length being about 1.9-2.1 X the height. The surface of the valves is marked with distinct rounded pits. The shell of R. californica has more pits than the European R. perpusilla, and has a distinctive pattern of pore-canals around the margin of the shell, ending in sensillae. The pore canals are slender, and not swollen in the mid-region, as in R. perpusilla. The hinge is undeveloped, and there is a dorsal median eye. Antenna 1 is 6-jointed, with 2 basal and terminal segments, ending in several long hairs. Antennae 2 is 5-jointed with 1 basal and 4 terminal segments, ending in a claw, and a flagellum with 2 segments. An oral cone is present, but does not terminate in a sucking disk. The 3 pairs of pereiopods are similar, with each terminating in a claw. The abdomen ends in 2 bristles. This ostracod is about 2 mm long. This description is based on de Vos and Stock 1956.

The taxonomic position of the genus Redekea is uncertain (Karanovic and Brandão 2014), but we have followed the World Registry of Marine Species in putting it in the family Paradoxistomidae (Appeltans et al. 2016).

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Taxonomy

Ecology

General:

Redekea californica is a commensal ostracod occurring on the appendages and abdomen of wood-boring isopods of the genus Limnoria (de Vos 1953; de Vos and Stock 1956). So far, it is known only from one collection, on Limnoria tripunctata, in San Diego Harbor. It is not known if it occurs on other species of Limnoria. Sexes are separate and fertilization is internal. Eggs are brooded. Development is direct. Males and females mature through 5 instars to maturity (Barnes 1983).

The native range and the extent of the introduced range of Redekea californica are unknown, but the host L. tripunctata has an extensive range in warm-temperate to tropical waters (Menzies 1957; Cookson 1990). Habitats include marinas and piers, floating and submerged logs, and vessel hulls (de Vos and Stock 1956). The mouthparts of R. californica do not appear specialized for parasitism (de Vos and Stock 1956), so it most likely feeds on microbes associated with the carapace and excreta of Limnoria spp.

Food:

Commensal, Limnoria tripunctata

Trophic Status:

Parasite

Paras

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Habitats

General Habitat	Coarse Woody Debris	None
General Habitat	Marinas & Docks	None
General Habitat	Vessel Hull	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Tidal Range	Low Intertidal	None
Vertical Habitat	Epibenthic	None

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Tolerances and Life History Parameters

Broad Temperature Range	None	Warm temperate
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

Redekea californica is known from only one location – San Diego Bay, California (de Vos and Stock 1956), and there are no reported impacts for this species.

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References

Appeltans, W. et al. 2011-2015 World Registry of Marine Species. <missing URL>



Barnes, Robert D. (1983) Invertebrate Zoology, Saunders, Philadelphia. Pp. 883

Calcinai, B.; Graziano, M.; Mori, M.; Cerrano, C. (2013) [Demographic structure of a population of Limnoria tripunctata Menzies 1951 (Crustacea, Limnoriidae) of the Ligurian Sea], Biologia Marina Mediterranea 20(1): 124-125

Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America., Ph.D. dissertation, University of California, Davis. Pp. 1-904

Cohen, Anne C.; Peterson, Dawn E.; Maddocks, Rosalie F. (2007) The Light and Smith Manual: Intertidal invertebrates from Central California to Oregon (4th edition), University of California Press, Berkeley CA. Pp. 417-446

Cookson, Laura J. (1990) Australasian Species of Limnoriidae (Crustacea: Isopoda), Memoirs of the Museum of Victoria 52(2): 137-262

de Vos, A. P. C.; Stock, J. H. (1956) On commensal Ostracoda from the wood-infesting isopod Limnoria, Beaufortia 55(5): 133-139

de Vos, A.P.C. (1953) Three new commensal ostracods from Limnoria lignorum (Rathke), Beaufortia 34(4): 21-3`

Karanovic, Ivana; Brandão, Simone Nunes (2014) Biogeography of deep-sea woodfall, cold seep and hydrothermal vent Ostracoda (Crustacea), with the description of a new family and a taxonomic key to living Cytheroidea, Deep-Sea Research II 111: 76-94

McKenzie, K. G. (1972) New data on the ostracode genera Laocoonella de Vos & Stock, Redekea de Vos, and Aspidoconcha de Vos; with a key to the family Xestoleberididae and a resume of symbiosis in Ostracoda, Beaufortia 19(254): 151-162

Menzies, Robert James (1957) The marine borer family Limnoriidae (Crustacea, Isopoda). Part I: Northern and Central America: Systematics, distribution, and ecology, Bulletin of Marine Science of the Gulf and Caribbean 7(2): 101-200

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