Distributional Ecology and Zoogeographical Relationships of Stomatopod Crustacea from Pacific Costa Rica: Smithsonian Contributions to the Marine Sciences, Number 7

摘要

The biota of the East Pacific region is relatively poorly known, despite its considerable Zoogeographie significance. The East Pacific has been separated from the West Atlantic region since the late Miocene (Durham and Allison, 1960; Woodring, 1966), and, although high levels of endemism are found there, many East Pacific species show affinities to taxa in the West Atlantic (Woodring, 1966; Briggs, 1974; Manning, 1977; Emerson, 1978). However, some East Pacific species are more closely related to taxa in the East Atlantic than to those in the West Atlantic. For example, a xanthid crab, Nanocassiope melanodactyla (A. Milne-Edwards, 1867), is known from the East Pacific and East Atlantic but not from the West Atlantic (Chace, 1966). The closest relatives of five species of East Pacific xanthid crabs (some of them restricted to the Galapagos) occur in the East Atlantic (Garth, 1968). One stomatopod crustacean, Squilla aculeata, is represented by subspecies in the East Pacific and East Atlantic but not the West Atlantic; and species in several other East Pacific stomatopod genera (Eurysquilla, Coronida, Lysiosquilla, and Pseudosquillopsis) show closest affinities to species in the East Atlantic (Manning, 1977). On the other hand, some species of mollusks occur in the Atlantic and Indo-West Pacific, but not the East Pacific (see Woodring, 1966; Emerson, 1978). Species of four stomatopod genera (Bathysquilla, Odontodactylus, Alima, Pseudosquilld) are present in the West Atlantic and Indo-West Pacific, but not in the East Pacific (Manning, 1969a; Manning and Struhsaker, 1976). An alpheid shrimp, Alpheusparacrinitus Miers, 1881, is known from the Indo-West Pacific, Clipperton Island in the East Pacific, and the East Atlantic, but does not occur on the East Pacific mainland or in the West Atlantic (Chace, 1962).