Scallasis caledonica
Creators: name: Komai, Tomoyuki
name: Poore, Gary C. B.
name: Fujita, Yoshihisa
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Callianassidae
Scallasis
Scallasis caledonica

description: Scallasis caledonica (Ngoc-Ho, 1991)
Callianassa caledonica Ngoc-Ho, 1991: 285–287, fig. 2.— Dworschak 2007: 307.
Trypaea caledonica.— Sakai 2011a: 395.
Scallasis caledonica.— Poore et al. 2019: 143.
Type material. Holotype: New Caledonia, Lagon Est, 21 m, 13 January 1987, female (cl 5.0 mm), MNHN-Th 1072.
Paratype: Same data as holotype, 1 female lacking pleon (cl 5.0 mm), MNHN-Th 1073; 1 male lacking pleon (cl 4.0 mm), 2 males (cl 4.5, 5.0 mm), MNHN-Th 1074.
Diagnosis. Pleomere 6 as long as wide. Telson 0.8 times as long as wide; greatest width 1.2 times posterior width. Maxilliped 3 ischium-merus 3 times as long as wide; merus free distal margin transverse, rounded. Female major cheliped ischium lower margin with 6–8 small spines; merus lower margin with simple proximal spine; palm 0.9 times as long as carpus. Male major cheliped merus lower margin as in female; dactylus as in female. Minor cheliped ischium lower margin with 10 small serrations; merus lower margin with 1 oblique spine at midpoint. Male pleopod 1 of 1 minute article. Male pleopod 2 absent. Uropodal endopod anterior margin with small spine about two-thirds along; dorsal surface with 1 long proximal spiniform seta, usually plus 1 shorter submarginal seta; exopod anterior margin with small spiniform seta about three-quarters along.
Distribution. Known only from the type locality in New Caledonia.
Remarks. Scallasis caledonica was originally described on the basis of five specimens from Lagon Est, New Caledonia (Ngoc-Ho 1991; as Callianassa). We have re-examined the type material and can confirm the accuracy of Ngoc-Ho’s figures, the only exception being the presence of two long facial spiniform setae and another distally on the anterior margin of the uropodal endopod. The male possesses a minute, pear-shaped pleopod 1 but lacks pleopod 2. Ngoc-Ho (1991) noted that the chelipeds were only slightly sexually dimorphic. Differences from S. amboinae are subtle: the distal margin of the merus of maxilliped 3 is less oblique, and the major cheliped is more compact, its meral tooth being proximal and triangular, rather than spine-like.
Sakai (1999) considered Callianassa caledonica a junior synonym of “ Callianassa ” pygmaea while Dworschak (2007) considered it a valid species. Sakai’s (2010) treatment of Callianassa caledonica was not consistent: under the account of Trypaea andamaniensis, he stated “ T. caledonica is considered to be a separate species”, whereas under the account of Trypaea tonkinae he viewed it as a questionable synonym.
description: Published as part of Komai, Tomoyuki, Poore, Gary C. B. & Fujita, Yoshihisa, 2020, Redescription of the poorly known ghost shrimp species, Scallasis amboinae Bate, 1888, review of the genus, and description of a new species from the Ryukyu Islands, Japan (Decapoda: Axiidea: Callianassidae), pp. 401-420 in Zootaxa 4766 (3) on page 408, DOI: 10.11646/zootaxa.4766.3.1, http://zenodo.org/record/3765527