New Record of Trapeziid Crab, Quadrella reticulata Alcock, 1989 (Brachyura: Trapeziidae) from the Persian Gulf

Brachyuran decapods of the families Grapsidae and Ocypodidae are a dominant faunal element of intertidal flats and mangroves in the Arabian Gulf and the Gulf of Oman. Recent collections along the coasts of the U.A.E. and Saudi Arabia and examination of material from other parts of the Gulf revealed in total six species of grapsid and 21 taxa (species and subspecies) of ocypodid crabs occurring in these habitats within the Arabian Gulf. Great differences in species diversity and composition exist between the different parts of the Arabian Gulf. Maximum diversity was observed for the easternmost part of the U.A.E. (Ras al Khaimah, Umm al Quwain) and for Kuwait. Highly reduced species numbers were found along the shorelines of Abu Dhabi and Saudi Arabia. The most likely factor causing this pattern is salinity. Zoogeographically it appears, that most of the Arabian Gulf species are of an ‘eastern’ (Indian) origin. ‘Western’ (East African and Red Sea) elements are restricted to the south-eastern part of the Gulf (coast of the U.A.E.) and to the Gulf of Oman.

The paper presents findings from a recent collection of crabs made during 1993 and 1994 from the mangal of the United Arab Emirates. The mangal invertebrate fauna of the UAE is not well known and an account is given of the families Grapsidae, Ocypodidae, Portunidae, Xanthidae and Leucosiidae collected from Umm Al Quwain khawr. For each species comments are made about their identification, habitat preferences and geographical distribution.

(1905). XXVIII.—Natural History Notes from the R.I.M.S. ‘Investigator,’ Capt. T. H. Henning, R. N. (retired), commanding.—Series III., No. 6. An Account of the new and some of the rarer Decapod Crustacea obtained during the Surveying Seasons 1901–1904. Annals and Magazine of Natural History: Vol. 15, No. 87, pp. 233-268.

A revision of the family Trapeziidae Miers, 1886, has shown that it consists of three clades, one of which is elevated to family status, Tetraliidae fam. nov., for the genera Tetralia Dana, 1851, and Tetraloides Galil, 1986. The genera Trapezia Latreille, 1828, Calocarcinus Calman, 1909, Hexagonalia Galil, 1986, Philippicarcinus Garth & Kim, 1983, Quadrella Dana, 1851, and Sphenomerides Rathbun, 1897, remain in the Trapeziidae; Domecia Eydoux & Souleyet, 1842, Jonesius Sankarankutty, 1962, Maldivia Borradaile, 1902, Palmyria Galil & Takeda, 1986, and the fossil genus Eomaldivia M ller & Collins, 1991, in Domeciidae Ortmann, 1893. Cladistic analysis shows that Trapeziidae sensu Miers, 1886, consists of three clades that show convergence as a result of similar habits as symbionts of reef corals and other cnidarians. A list of all recognised genera and species in the three families and their primary synonyms is provided. Keys are also included for four families of Brachyura symbiotic with reef corals, and for the genera and species of Domeciidae, Tetraliidae, and Trapeziidae. Some rare colour figures are reproduced. Three name changes have resulted within the Tetraliidae: Cancer glaberrimus Herbst, 1790, for Tetralia fulva Ser ne, 1984, and Cancer mutus Linnaeus, 1758, for Tetralia armata Dana, 1852, and Tetralia vanninii Galil & Clark, 1988. Nomenclatural problems associated with the repeated use of "forma typica" for various species of Trapezia and Tetralia are resolved. To stabilise the nomenclature of a number of well-known species, neotypes are designated for 13 species of Trapeziidae for which type material is not extant: Trapezia cymodoce (Herbst, 1801), and its three synonyms (Trapezia dentifrons Latreille, 1828, Trapezia dentata var. subintegra Dana, 1852, Trapezia cymodoce var. ornatus Chen, 1933); Trapezia bidentata (Forsk l, 1775), and one of its synonyms (Trapezia ferruginea Latreille, 1828); Trapezia digitalis Latreille, 1828, and one of its synonyms (Trapezia nigrofusca Stimpson, 1858); Trapezia septata Dana, 1852, and one of its synonyms (Trapezia reticulata Stimpson, 1858); Trapezia areolata Dana, 1852; Trapezia bella Dana, 1852; and Trapezia speciosa Dana, 1852. Neotypes are also designated for seven species of Tetraliidae: Tetralia glaberrima (Herbst, 1790), and three synonyms (Trapezia integra Latreille, 1828, Trapezia serratifrons Jacquinot, 1846, Tetralia laevissima Stimpson, 1858); Tetralia muta (Linnaeus, 1758), and one of its synonyms (Tetralia armata Dana, 1852); and Tetraloides nigrifrons (Dana, 1852).

Vingt-sept especes appartenant a cinq genres de la famille Trapeziidae vivent dans les eaux de l'ocean Indien et de la mer Rouge. Il s'agit de : Hexagonalia brucei, Quadrella boopsis Q coronata, Q. maculosa, Q. reticulata, Q. serenei, Tetralia cavimana. T. cinctipes, T. fulva, T. nigrolineata, T. rubridactyla, T. vanninii, Tetraloides heterodactyla, Tetraloides nigrifrons, Trapezia cymodoce, Tr. digitalis, Tr. ferruginea, Tr. flavopunctata, Tr. formosa, Tr. guttata, Tr. lutea, Tr. punctipes, Tr. richtersi, Tr. rufopunctata, Tr. septata, Tr. speciosa, Tr. tigrina, La position taxonomique d'une espece, Quadrella serenei Galil, 986, est discutee et l'espece est redecrite. Q. serenei a ete initialement designee comme Q. cyrenae Ward, 1942 mais on conclut que Ward a utilise des specimens de Q. maculosa Alcock, 1898 dans sa description ; Q. lewinsohni Galil, 1986 est un synonyme subjectif de Q. serenei, Une autre espece, Trapezia punctipes Castro. 1997, est signalee dans la region pour la premiere fois.

ABSTRACT Eleven Red Sea members of the coral-inhabiting family Trapeziidae arc described and illustrated. A key, restricted synonymic lists and distributional information are provided. New records are given for the three species of the genus Quadrella.