Three species of Acanthaxius Sakai & de Saint Laurent, 1989, including two new to science, from the Solomon Islands and New Caledonia (Crustacea, Thalassinidea, Axiidae) Author Ngoc-Ho, Nguyen text Zootaxa 2006 1240 57 68 journal article 10.5281/zenodo.172858 46fb19e6-b349-43f0-8a1d-320ac68eea5e 1175­5326 172858 Genus Acanthaxius Sakai & de Saint Laurent, 1989 Remarks The genus Acanthaxius was created by Sakai & de Saint Laurent (1989) for eight species with Axiopsis ( Axiopsis ) pilocheira Sakai, 1987 as type species. Later, Sakai (1994) increased, with A. polycheates , the number of species to nine. Kensley (1996) considered that “ the definition of this genus contains some uncertainties ”, redefined it and limited the number of species to five: A. miyazakiensis (Yokoya, 1933) from Japan , A. amakusana (Miyake & Sakai, 1967) and A. polyacantha (Miyake & Sakai, 1967) from the East China Sea, A. pilocheira ( Sakai, 1987 ) from Japan , A. polychaetes Sakai, 1994 from the Great Barrier Reef, Australia , and added A. kirmilleri Kensley, 1996 from off Anguilla . Two other species were established in 1998: A. formosa Kensley & Chan and A. grandis Kensley & Chan , both from Taiwan . Ngoc­Ho (2005) , describing a specimen of Axius spinosissimus Rathbun, 1906 from French Polynesia , agreed with Kensley (1996) that although this species was placed in Acanthaxius by Sakai & de Saint Laurent (1989) , it did not fit the generic definition and should logically be assigned to a new genus. Nevertheless, as it comprised only three specimens including the holotype , all damaged, it seemed undesirable to establish a monotypic taxon on a material in such poor condition. The species was provisionally retained in Acanthaxius ( Ngoc­Ho, 2005 ). According to Kensley (1996) , the advanced characters of the genus are the relatively slender and dentate rostrum, with its basal pair of spines in a supraorbital position; the form of the pereopod 1 chela, and especially that of the small pereopod 1, with slender dentate fingers being 1.5–2.0 times longer than the propodal palm; the presence of spines on the upper margins of the dactylus and propodus of the pereopod 1 chela; the absence of pleurobranchs; and the presence of epipods on pereopods 1–4. The new species studied agree well with this scheme except for the fingers of the pereopod 1 in A. gadaletae n. sp. being only about 1.2–1.3 longer than the palm. It can also be noted that all known Acanthaxius species have a slender and incurved tip of the antennal article 2, as pointed out by Sakai & de Saint Laurent (1989) , which could be considered as diagnostic.