Acidopsinae Stevcic 2005
Creators: name: Ng, Peter K. L.
name: Rahayu, Dwi Listyo
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Acidopsidae

description: Subfamily Acidopsinae Števčić, 2005
Acidopidae [sic] Števčić, 2005: 36.
Parapilumnidae Števčić, 2005: 70.
Diagnosis. Eye mobile, not pear-shaped, cornea as wide as or wider than peduncle with cornea round, pigmented; or elongated, with distal part gently tapering, cornea small but pigmented; basal antennal article quadrate, as wide as long (Figs. 6A, B, 11D); epistome level, not sunken (Fig. 12A); anterolateral angle of third maxilliped merus angular (Figs. 5A, B, 10C, 11E); lateral edge of a3 between cx4, 5; lateral edge of a2 adjacent to cx5, st8 barely visible when abdomen closed (Figs. 1A–D); male opening coxal, penis short; male abdomen completely protects penis when closed; only small part of st8 visible when abdomen closed; female sterno-abdominal cavity deep, transversely narrow, vulvae positioned close to median longitudinal groove of st6 (Figs. 3, 10D).
Material examined. Acidops fimbriatus Stimpson, 1871: 1 female (19.7 × 14.9 mm) (MNHN-IU-2013- 9470), station 8, bottom of coral reef, brushing, 10°18.49’N 109°14.1’W, Clipperton I., Expedition CLIPPERTON, coll. J. M. Bouchard et al., 14 January 2005; 1 female (19.2 × 14.6 mm) (USNM 1191707) [photographs examined], Angel de la Guardia I., 10–15 fms (20–31 m), Puerto Refugio, Mexico, coll. F. E. Lewis, 14 April 1939. Acidops cessacii (A. Milne-Edwards, 1878): 1 male (7.7 × 5.9 mm), 1 female (14.1 × 10.0 mm) (NHM 99.3.23.66–67) (syntypes of Epimelus cessacii A. Milne-Edwards, 1878), Cape Verde Is., 10–30 m; 1 male (11.3 × 8.1 mm), 1 female (12.6 × 9.9 mm) (ZRC 1998.58), beach and tide pools on rocky point west of main beach, North East Bay, Ascension, coll. R.B. Manning 19 May 1971; 1 ovigerous female (9.7 × 7.3 mm) (ZRC 2013.1459), rocky shores, under large rocks, 0.5–1 m, near Pato Alegre, São Tomé, coll. A. Anker, 5 February 2006. Parapilumnus cristimanus (A. Milne-Edwards, 1873): lectotype female (16.5 × 13.0 mm) (MNHN-B 12938), Upolu, Samoa, coll. M. Balansa; paralectotype female (14.5 × 10.9 mm) (MNHN-B 12939), New Caledonia, coll. M. Balansa; 1 male (10.2 × 7.6 mm) (IOCAS SSFVI2-2), 1 male (16.3 × 12.5 mm) (ZRC 2003.90), Nansha Is. (Spratly Is.), South China Sea, coll. 9 May 1989; 1 female (23.2 × 17.7 mm) (ZRC 2013.1905, ex MNHN 2013- 268), station PR 10, outer slope, 22 m, Paeowa I., 05°10.8'S 145°49.8'E, Papua New Guinea, coll. Expedition PAPUA NUIGINI, 8 November 2012; 1 female (10.1 × 8.0 mm) (MNHN 2013-513), station PR 48, Malamal Passage, Sek I., 5°07.2'S 145°49.4'E, Papua New Guinea, coll. Expedition PAPUA NUIGINI, 17 November 2012. Parapilumnus oryctus Ng, 2002: Holotype male (12.3 × 10.5 mm) (ZRC 2002.174), Luminao fore reef, in rubble, 20–25 m, Guam, coll. H.T. Conley, May 1998.
Remarks. The history of the family has already been discussed at length earlier. The genera Acidops Stimpson, 1871, and Parapilumnus Kossmann, 1877, are relatively well studied (see Monod 1956; Guinot & Ribeiro 1962; Manning & Holthuis 1981; Ng 2002; Ng & Chen 2004; Guinot et al. 2013). Epimelus cessacii A. Milne-Edwards, 1878, was described as the type species of Epimelus A. Milne-Edwards, 1878, based on material from Cape Verde Is. Monod (1956: 358–359) discussed the status of Epimelus and argued it was a junior subjective synonym of Acidops, noting that at his request, John Garth compared the two respective type species and no major differences could be found to warrant two genera. Rathbun (1930: 533, pl. 215) reported that material from Australia also belongs to A. fimbriatus. Garth (1946: 475) figured a male specimen of A. fimbriatus from the Galápagos Is. and argued that Rathbun’s Australian material did not belong to this species. We agree that Rathbun’s (1930: pl. 215) figure of her South Australian specimen closely resembles a species of Heteropilumnus De Man, 1895 (Pilumnidae) instead, and is clearly not a species of Acidops. Our comparisons show no major characters separating them, and we agree with Monod (1956) that Acidops fimbriatus Stimpson, 1871, and Epimelus cessacii A. Milne- Edwards, 1878, are congeneric but are different species.
Acidops fimbriatus and A. cessacii are indeed very similar (Fig. 7A–D). Comparisons of the female specimens of both species on hand show only minor differences: the basal antennular article of A. fimbriatus is relatively wider and larger, the front is proportionately more produced and the anteroexternal margin of the third maxilliped is relatively less angular and more rounded. Their colours in life also seem to differ, with A. fimbriatus a relatively uniform yellowish-brown on all its dorsal surfaces (Fig. 40A) while A. cessacii is dirty white with small patches of maroon (Fig. 40B). It is possible there will be more differences that when the male abdomen and gonopods of A. fimbriatus can be described and figured. For the moment, in view of the different distributions (one Pacific and the other Atlantic) and the differences observed above, it is best to recognise both species as valid.
The specimens of Acidops cessacii examined (including two syntypes) show some variation. The anterolateral margins show three low granuliform teeth (excluding the external orbital tooth), separated by low notches, accentuated by a short, shallow groove on the carapace. The grooves can be rather indistinct in some specimens and/or depending on the angle from which the carapace is viewed, giving the appearance that the carapaces look different (Fig. 7A, C, D and Fig. 7B) (see also A. Milne-Edwards & Bouvier 1900: pl. 15 figs. 1–8).
Acidops fimbriatus occurs in the eastern Pacific, from California, Mexico to Clipperton I. and the Galápagos (Garth 1946; Hendrickx 1995; Poupin et al. 2009). Acidops cessacii has a wide distribution in the Atlantic, occurring from West Africa to Brazil (see Monod 1956; Manning & Holthuis 1981; Barreto et al. 1993; Melo 1996).
With regards to Parapilumnus, the additional specimens of P. cristimanus from Papua New Guinea partially fill in a geographical gap; the species was previously only known from New Caledonia and the South China Sea. They agree well with the redescriptions and figures of the species by Ng (2002) and Ng & Chen (2004). Comparisons of all the material of the two species on hand indicate that the differences in the carapace granulation, form of the ambulatory legs and chelae cited by Ng (2002) to separate P. cristimanus from P. oryctos (known only from Guam) are not reliable and vary too much to be useful (see also Ng & Chen 2004). The carapace proportions remain useful, with that of P. oryctos still the most rounded (width to length ratio of 1.2, Fig. 8C) while all P. cristimanus, including the recent material, have ratios of 1.3 (Fig. 8A). In addition, there are also marked differences in the form of the male abdomen and G1 structures of the two species (see Ng & Chen 2004).
Interestingly, both species have similar colour patterns, with the dorsal surface of the carapace dirty white with regularly arranged patches and spots of red or orange; and the legs have bands and patches of red and orange (Fig. 40C, D). In this respect, Parapilumnus is similar to Crinitocinus gen. nov. (Fig. 40E–H).
description: Published as part of Ng, Peter K. L. & Rahayu, Dwi Listyo, 2014, Revision of the family Acidopsidae Števčić, 2005, and the systematic position of Typhlocarcinodes Alcock, 1900, Caecopilumnus Borradaile, 1902, and Raoulia Ng, 1987, with descriptions of two new genera and five new species (Crustacea: Brachyura: Goneplacoidea), pp. 1-63 in Zootaxa 3773 (1) on pages 9-14, DOI: 10.11646/zootaxa.3773.1.1, http://zenodo.org/record/4909796