Camatopsis minor, Ng, Peter K. L. & Castro, Peter, 2016

Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), Zootaxa 4209 (1), pp. 1-182 : 42-44

publication ID	https://doi.org/ 10.11646/zootaxa.4209.1.1
publication LSID	lsid:zoobank.org:pub:849BAB5C-464A-4B4A-A586-5742411EDC01
DOI	https://doi.org/10.5281/zenodo.5617101
persistent identifier	https://treatment.plazi.org/id/F16BFB33-FF8A-FFD0-FF6A-FB7DFBC5FD56
treatment provided by	Plazi
scientific name	Camatopsis minor
status	sp. nov.

Treatment

Camatopsis minor View in CoL n. sp.

( Figs. 8 View FIGURE 8 G, H; 23F; 39G, H; 69A‒F; 86E)

? Camatopsis rubida View in CoL — Serène & Soh 1976: 23, fig. 21 [Andaman Sea]. Not Camatopsis rubida Alcock & Anderson, 1899 View in CoL . Camatopsis rubida Forma View in CoL B—Tesch 1918: 235 (part) [ Indonesia] (other Forma B specimens = Microtopsis teschi View in CoL n. sp.). Not Camatopsis rubida Alcock & Anderson, 1899 View in CoL .

Type material. Holotype male (3.6 × 4.3 mm) (NNM-ZMA), Indonesia, Java, Kwandang Bay , Siboga Expedition , stn 114, 75 m.

Paratypes: 2 females (4.0 × 4.9 mm, 2.7 × 3.5 mm) (NNM-ZMA), collected with the holotype.

Other material examined. Indonesia. SIBOGA EXPEDITION : 1 male (3.8 × 4.6 mm) , 2 males (partially crushed) (NNM-ZMA), stn 116, west of Kwandang Bay entrance, 72 m, 07.1899 ; 1 male (3.4 × 4.0 mm) ( NNM- ZMA), stn 260, northwest of Kei Is. , 90 m, 0 7.1899.

Diagnosis. Carapace ( Fig. 8 View FIGURE 8 G, H) subtrapezoidal, 1.0‒1.3 wider than long; front bilobed, with shallow to sometimes deep median cleft; anterolateral margins arcuate, carapace minutely granular with granules higher along lateral margins, without distinct lobes or teeth. Eye peduncle ( Fig. 23 View FIGURE 23 F) filling orbit, short, slightly mobile; cornea reduced, with reduced pigmentation. Epistome ( Fig. 23 View FIGURE 23 F) with wide, semicircular median lobe with deep median fissure, semicircular lateral margins. Third maxilliped merus subcircular, ischium subquadrate, about same length as merus. Proportionally short ambulatory legs ( Fig. 8 View FIGURE 8 G). Chelipeds ( Figs. 8 View FIGURE 8 G, H; 39G, H) subequal in length, slightly dissimilar in females, heteromorphic in males. Major chela of males ( Fig. 39 View FIGURE 39 G) with thick propodus, cutting margins with small teeth, distal end of pollex overlapping dactylus. Minor chela of both sexes ( Fig. 39 View FIGURE 39 H) with short teeth of about same size. Inner margin of cheliped carpus smooth. Fused thoracic sternites 1, 2 ( Fig. 69 View FIGURE 69 A) triangular, proportionally narrow, short. Male pleon ( Fig. 69 View FIGURE 69 B) with proportionally short telson. G1 ( Fig. 69 View FIGURE 69 C‒E) stout, distal segment straight, tip directed upwards, with short spinules, distal segment flared, medially cleft. G2 ( Fig. 69 View FIGURE 69 F) about 1/2 G1 length, straight, slender, distal segment short, straight. Female pleon ( Fig. 86 View FIGURE 86 E) with lateral margins of somites strongly convex; telson proportionally short. Sterno-pleonal cavity moderately deep, vulvae far apart from each other.

Etymology. The species epithet minor alludes to the small size of adults.

Remarks. The recognition of this new species is necessary because it appears to mature at a much smaller adult size than in other Camatopsis species as well as having a characteristic G1 structure. Serène & Soh (1976: 23, fig. 21) recorded and figured the G1 of a small male specimen (4.5 × 5.0 mm) from Phuket in the Andaman Sea that they identified as “ Camatopsis rubida ”. The G1 is characteristic by being straight with the tip flared and with a median cleft. We have found the same G 1 in small specimens from the Indonesia Siboga material that we initially assumed belonged to young males with the structure expected to change with growth. Small specimens of C. rubida and C. leptomerus n. sp., however, at less than 4 or 5 mm in carapace width from Indonesia and Philippines already have the characteristic G1 structure of their respective species (e.g., Fig. 68 View FIGURE 68 A, B), and as such, the differences observed with C. minor n. sp. cannot be attributed to growth. In addition, small females of C. minor n. sp. already have the pleon and pleopods fully developed. The smaller chela of C. minor n. sp., however, does not have the two upright, vertical teeth on the cutting margin of the pollex that is typical of adults of Camatopsis species. While the chelae of C. minor n. sp. show asymmetry, with one chela swollen and enlarged ( Fig. 39 View FIGURE 39 G, H), indicating it is already mature, small specimens of other Camatopsis species of a similar size generally have both chelae similarly structured (e.g., Figs. 39 View FIGURE 39 C, D). As such, we recognise a new species for this Indonesian material that was originally been identified by Tesch (1918) as “ Camatopsis rubida Form B ” (see discussion under C. rubida ). We also provisionally include Serène & Soh’s (1976) record from the Andaman Sea.