Galacantha A. Milne-Edwards, 1880

Published, First, 2007, Species of the genus Munidopsis Whiteaves, 1784 from the Indian and Pacific Oceans and reestablishment of the genus Galacantha A. Milne-Edwards, 1880 (Crustacea, Decapoda, Galatheidae), Zootaxa 1417, pp. 1-135 : 7-9

Genus Galacantha A. Milne-Edwards, 1880

Type species: Galacantha rostrata A. Milne-Edwards, 1880 , by original designation (gender: feminine).

Diagnosis. Carapace subquadrangular, slightly longer than wide, covered with small granules, simple spines, scale-like or spine-like tubercles, dorsally armed with one extremely strong laterally compressed mesogastric, and one moderately large cardiac spines. Lateral margin slightly convex, with 1 or 2 prominent anterior spines. Front margin oblique, without antennal spine. Posterior margin of carapace smooth. Rostrum with rostral spine upturned distally, and sometimes with 2 small subparallel spines or divergent well-developed spines at end of horizontal portion. Small spine ventral to front margin between ocular peduncle and antennal peduncle. Sternites smooth. Second through fourth abdominal tergites with 2 moderately elevated transverse ridges, each anterior ridge with prominent median spine. Eye movable and spineless, corneae subglobular. P1 covered with granules or small spines. P2–P4 long, slender. P2 overreaching P1. P2–P4 dactyli compressed laterally, flexor border moderately curving, bearing proximally diminishing low teeth. Epipods present on P1–P3.

Remarks. The genus Galacantha was described by A. Milne-Edwards in 1880, in a preliminary report on the crustaceans collected by the “Blake” during the first major trawling expedition in the Gulf of Mexico and Caribbean Sea. A. Milne-Edwards gave only a brief description, and the formal report of the “Blake” galatheids did not appear until several years later (A. Milne-Edwards & Bouvier, 1897). The genus included two species: G. rostrata and G.spinosa . Galacantha was used as a valid genus by numerous authors: Smith (1882), Filhol (1885), Henderson (1885, 1888), Wood-Mason (1891), Ortmann (1892), Faxon (1893, 1895), Alcock & Anderson (1894, 1896), Anderson (1896), Alcock (1901), Alcock & McArdle (1901), Benedict (1902), Hansen (1908), Stebbing (1908), Balss, 1913, Barnard (1950), Tirmizi (1966) and Kensley (1968).

The genus included numerous nominal species: G. rostrata A. Milne-Edwards, 1880 , G. spinosa A. Milne- Edwards, 1880, G. bellis Henderson, 1885 , G. talismani Filhol, 1884 (different from G. talismanii of Henderson, 1888), G. camelus Ortmann, 1892 , G. diomedeae Faxon, 1893 , G. investigatoris Alcock & Anderson, 1894 , G. trachypus Anderson, 1896 , G. areolata Wood-Mason, 1891 , G. faxoni Benedict, 1902 , and G. valdiviae Balss, 1913 . It also included some varieties: G. diomedeae var. parvispina Faxon, 1893 , G. rostrata var. investigatoris Alcok, 1901 , and G. spinosa var. trachynotus Alcock, 1901 .

The low number of available specimens at the first part of the last century, and some doubts about the validity of several characters, e.g., shape of spines at end of horizontal portion of rostrum, lead some authors to synonymise some species. For instance Faxon (1895) suggested that G. bellis , G. talismani and G. areolata should be included under G. rostrata . The taxonomic position of these species has been maintained until now (see Baba, 2005 and references). Benedict (1902) in his large work on galatheids recognized only seven species: G. camelus , G. faxoni , G. investigatoris , G. rostrata , G. spinosa and G. trachynotus . He considered G. rostrata var. investigatoris as a full species ( G. investigatoris ) and synonymized G. talismani , G. bellis and G. areolata with G. rostrata . Furthermore, he considered G. spinosa var. trachynotus as a full species, G. trachynotus . Doflein & Balss (1913) in their biogeographic revision of the family only included G. camelus , G. diomedeae , G. rostrata , G. spinosa , G. trachynotus and G. valdiviae . Later, Chace (1942), in his excellent work on the galatheids from the Caribbean Sea, suggested some important changes at generic and specific levels. First, he considered that the genus Galacantha should be included into the genus Munidopsis (as the other genera created by A. Milne-Edwards, see Introduction). Chace suggested that the peculiar form of the rostrum was also found in other species: e.g. ( M. expansa Benedict, 1902 , M. gilli Benedict, 1902 , M. cubensis Chace, 1942 ). Furthermore, G. camelus seemed to represent an intermediate step between the genus Munidopsis and Galacantha , indicating the absence of a clear separation between genera. Second, he synonymized G. rostrata with G. talismani , G. bellis , G. areolata , G. investigatoris and G. faxoni . Nevertheless, he recommended examination of all available specimens (ca. 40) from all oceans in order to obtain additional evidence for their taxonomic position.

After the examination of the material included in the present paper, it was concluded that the genus Galacantha is a valid genus, with a combination of characters that are not shared by other species, e.g., carapace with one extremely strong laterally compressed mesogastric spine, and one moderately large cardiac spine, one or two prominent anterolateral spines, rostral spine upturned distally, second through fourth abdominal tergites with anterior ridge each with prominent median spine, eye movable and spineless, P2 always overreaching P1, and epipods present on P1–P3. Additionally, the examination of numerous specimens from different localities of the Indian and Pacific Oceans indicated the constancy of some characters, previously considered as intraspecific variations (e.g. presence/absence and direction of spines at end of horizontal portion of rostrum).

Unfortunately, some taxonomic problems are not completely solved in the present work: (1) Galacantha faxoni described originally as G. rostrata by Faxon (1893) from individuals collected in the western Pacific Ocean, and named by Benedict (1902) as a new species, have not been examined (but see the Remarks in G. rostrata ); (2) G. talismani was described by Filhol (1885) from individuals collected off northwest Africa. These specimens are probably lost, but the shape and armature of the rostrum and carapace indicate that the species may be synonymized with G. rostrata . Henderson (1888) cited G. talismanii in the Banda Sea ( Indonesia) from a small juvenile with a long rostral spine and minute subparallel spines at the end of the horizontal portion. Its taxonomic status is uncertain, although it could probably be identified as G. bellis (see also under the Remarks of G. bellis ). Nevertheless, the name talismani is used for a valid species ( Munidopsis talismani A. Milne-Edwards & Bouvier, 1894 from the NW Africa). (3) The type material of G. areolata from the “Investigator” has not been examined and, although the original descriptions and illustration are excellent, the status of G. areolata and G. bellis should re-examined (see under the Remarks of G. bellis ).

In the present paper, a large number of individuals, belonging to different species, have been examined. Three new species are described ( G. subrostrata , G. subspinosa and G. quiquei ), the taxonomic position of some species is discussed and some additional data and figures for the all species collected are included.

The species considered in the genus are the following: G. bellis Henderson, 1885 , G diomedeae Faxon, 1893 , G. quiquei n. sp., G. rostrata A. Milne-Edwards, 1880 , G. spinosa A. Milne-Edwards, 1880 , G. subspinosa n. sp., G. subrostrata n. sp., G. trachynotus Anderson, 1896 , and G. valdiviae Doflein & Balss, 1913 .