On a new species of Alpheus (Crustacea Decapoda, Natantia) from the Eastern Medeterranean

From 30 October to 3 November 1975 an expedition, organized by the Department of Zoology of the University of Tel-Aviv, investigated the marine fauna of the Eastern Mediterranean north of Sinai Peninsula, R.V. "Shikmona" for this purpose was kindly placed at the disposal of the expedition by the Israel Oceanographic and Limnological Research Ltd. The expedition worked on the continental shelf at depths of about 25 to 65 m and its stations (indicated with the letters SIM, for Sinai-Israel-Mediterranean) ranged from 32o 41' to 34o 11Έ. In the collections a species of Alpheus was found which proved to be different from any species so far reported from the Mediterranean. Therefore it was suspected that it was of Indo-West Pacific origin and had migrated from the Red Sea through the Suez Canal. Although a closer examination of the material showed that it indeed is closely related to several Indo-West Pacific species, it could not be assigned to any of the known species. Therefore it is described here as new. Additional material of this new species, collected off the southern coast of Israel, was received from Mrs. B. Galil, and is also included in the present paper. The abbreviation cl. is used for carapace length. Alpheus migrans new species Mediterranean off the north coast of Sinai Peninsula: 31°28'N 33o22Έ; depth 62.18 m (34 fathoms); 2 November 1975; SIM Sta. 18. — 3 specimens (cl. 5-6.5 mm). 31°26'N 34o 11Έ; bottom mud; depth 36.6 m (= 20 fathoms) ; 30 October 1975; SIM Sta. 2. — 23 specimens (cl. 4.5-7 mm). 31°23' N 33o 22Έ; bottom mud; depth 27.43 m (=15 fathoms); 2 November 1975; SIM Sta. 16. — 4 specimens (cl. 4.5-5 mm).