Ž . Comparative Biochemistry and Physiology Part B 130 2001 7582 Genetic relationship among Japanese sentinel crabs ž / Decapoda: Ocypodidae: genus Macrophthalmus Toru Horii a , Jun Kitaura b , Keiji Wada c , Mutsumi Nishida a,  a Department of Marine Sciences, Faculty of Science, Uni  ersity of the Ryukyus, Okinawa, Japan b Department of Natural and En ironmental Science, Graduate School of Human Culture, Nara Women’s Uni  ersity, Nara, Japan c Department of Biological Science, Faculty of Science, Nara Women’s Uni  ersity, Nara, Japan Received 18 December 2000; received in revised form 23 April 2001; accepted 25 April 2001 Abstract Ž . Ž . Seven species eight populations of sentinel crabs genus Macrophthalmus from the Japan coast and Uca  ocans and Ocypode ceratophthalma , were examined electrophoretically for genetic variations in 13 enzymatic and one non- Ž enzymatic protein comprising 17 loci. Most species were highly differentiated from each other Nei’s genetic distance, . 0.29 1.63 . The least genetic distance was found between M. japonicus and M. banzai, the genetic distinctiveness of the two taxa being supported by three divergent loci with no common allele. The genetic relationships among Macrophthal - mus species differed greatly from those inferred from morphological features, with a UPGMA tree suggesting that the sub-genus Macrophthalmus is polyphyletic.  2001 Elsevier Science Inc. All rights reserved. Keywords: Allozyme; Crustacea; Macrophthalmus; Macrophthalmus banzai; Macrophthalmus japonicus; Ocypodid crabs; Phylogeny; Taxonomy 1. Introduction Ž Sentinel crabs genus Macrophthalmus La- . treille, 1829 inhabit subtidal and tidal flats of various substrata, such as mud, sand, rock, dead coral reef and seagrass, in the temperate to tropi- cal Indo-West Pacific region. The genus currently Ž includes 41 extant species Barnes, 1977; Serene, `  Corresponding author. Present address: Department of Marine Bioscience, Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo 164-8639, Japan. Tel.: 81-3-5351-6329; fax: 81-3-5351-6579. Ž . E-mail address: mnishida@ori.u-tokyo.ac.jp M. Nishida . 1981; Wada and Sakai, 1989; Takeda and Komai, . 1991; Holthuis, 1995; Poupin, 1997 and is classi- Ž fied into seven subgenera Hemiplax, Macro- phthalmus, Mareotis, Mopsocarcinus, Para- .Ž mareotis, Tasmanoplax and Venitus Barnes, 1967; . Komai et al., 1995 . The taxonomy of Macroph- thalmus was substantially clarified by a series of Ž . studies by Barnes 1967, 1971, 1973, 1977 , but the phylogenetic relationship has not so far been examined. Japan is represented by 18 Macrophthalmus Ž species Sakai, 1976; Takeda, 1981; Wada and Sakai, 1989; Takeda and Komai, 1991; Kosuge . and Wada, 1992; Kitaura and Wada, 1999 . The 1096-495901$ - see front matter  2001 Elsevier Science Inc. All rights reserved. Ž . PII: S 1 0 9 6 - 4 9 5 9 01 00409-2