PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 114(1):109-119. 200L Description of two new species of Polyonyx Stimpson, 1858 from the Indo-West Pacific, with a key to the species of the Polyonyx sinensis group (Crustacea: Decapoda: Porcellanidae) Bemd Werding Institut fiir Allgemeine und Spezielle Zoologie, Stephanstrasse 24, D-35390 Giessen, Germany Abstract. — Two new species of the genus Polyonyx Stimpson, 1858, P. tu-learis and P. thai are described. The new species belong to the P. sinensis group, which currently contains 11 species from the Indo-West Pacific, three from the eastern Atlantic, and three from American waters. A key for all spe-cies in this group is included. The Polyonyx sinensis species group was defined by Johnson (1958: 97) for taxa characterized by him as follows: "Lateral margins of carapace without spines. Cara-pace broader than long, transversely ovate, or rectangular with rounded comers. Front rather narrow, trilobate with the median lobe broad and rounded and projecting little beyond the lateral lobes, which are often scarcely developed so that the front is al-most straight. Chelipeds with the anterior margins of the carpus and merus unarmed; a more or less marked development of hairs on their outer, and often also on their inner surfaces. Legs hairy dorsally, and often the carapace also more or less hairy. Dactyl of the walking legs with the dorsal claw much smaller than the ventral claw, and bearing two or three accessory spinules." Most of the species are definitely known to live as commensals of tube dwelling polychaetes. The species of the group are widespread in the Indo-West Pacific where it is represent-ed now by 1 1 species. Three additional spe-cies are known from the tropical eastern At-lantic and three from American waters. When Johnson (1958) revised the Indo-West Pacific species of the genus Polyonyx, the genus comprised 14 species, some of which were assigned to other genera by lat-er workers (Ng & Sasekumar 1993). Of the Indo-West Pacific species attributed to the P. sinensis group by Johnson (1958), P. si-nensis Stimpson, 1858, P. utinomii Miyake, 1943, P. pedalis Nobili, 1905, and P. trans-versus (Haswell, 1882), are currently con-sidered as valid. In addition, P. loimicola SankoUi, 1965, P. maccullochi Haig, 1965, P. haigae McNeil, 1968, P. vermicola Ng & Sasekumar, 1993, and P. bella Hsueh & Huang, 1998, have been described since then and adescribed to the P. sinensis group by the original authors. P. bella is consid-ered a junior synonym of P. sinensis (see Discussion). The position of P. plumatus Yang & Xu, 1994 was not discussed at all in the original description, it seems to be identical with P. haigae and is considered a junior synonym of that species. P. com-etes Walker, 1887 which was included in the P. sinensis group by Johnson (1958) was placed in a new genus by Ng & Na-kasone (1993) but is considered a member of the P. sinensis group in this paper since it fits in all respects with Johnson's defini-tion. The three Polyonyx species from west-em Africa (Chace 1959) correspond with the basic morphological features of the P. sinensis group and have to be included here. The same is true for three species from the Americas which were recognized by Haig (1960) as clearly belonging to Johnson's P. sinensis group. The type spe-cies of the genus, P. gibbesi, is the only
Description Of Two New Species Of Polyonyx Stimpson, 1858 From The Indo west Pacific, With A Key To The Species Of The Polyonyx Sinensis Group (Crustacea : Decapoda : Porcellanidae)
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