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

Camatopsis minor n. sp.

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

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

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 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 F) filling orbit, short, slightly mobile; cornea reduced, with reduced pigmentation. Epistome ( Fig. 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 G). Chelipeds ( Figs. 8 G, H; 39G, H) subequal in length, slightly dissimilar in females, heteromorphic in males. Major chela of males ( Fig. 39 G) with thick propodus, cutting margins with small teeth, distal end of pollex overlapping dactylus. Minor chela of both sexes ( Fig. 39 H) with short teeth of about same size. Inner margin of cheliped carpus smooth. Fused thoracic sternites 1, 2 ( Fig. 69 A) triangular, proportionally narrow, short. Male pleon ( Fig. 69 B) with proportionally short telson. G1 ( Fig. 69 C‒E) stout, distal segment straight, tip directed upwards, with short spinules, distal segment flared, medially cleft. G2 ( Fig. 69 F) about 1/2 G1 length, straight, slender, distal segment short, straight. Female pleon ( Fig. 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 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 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 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.

Distribution. Indonesia and questionably Andaman Sea. Depth: 72‒ 90 m.

Figures

FIGURE 8. Overall dorsal view of species of Camatopsis. A, C. leptomerus n. sp., Philippines: holotype male 10.5 × 11.3 mm (NMCR); B, C. leptomerus n. sp., Philippines: paratype female 12.7 × 13.2 mm (ZRC 2015.170); C, C. leptomerus n. sp., Philippines: paratype female 3.4 × 4.0 mm (ZRC 2015.159); D, C. leptomerus n. sp., Philippines: paratype female 4.8 × 5.8 mm (ZRC 2015.154); E, C. leptomerus n. sp., Indonesia: male 4.2 × 5.0 mm (NNM-ZMA 241605 c); F, C. leptomerus n. sp., Philippines: paratype male 3.1 × 3.4 mm (ZRC 2015.120); G, C. minor n. sp., Indonesia: holotype male 3.6 × 4.3 mm (NNM- ZMA); H, C. minor n. sp., Indonesia: paratype female 4.0 × 4.9 mm (NNM-ZMA).

FIGURE 23. Frontal view of cephalothorax of species of Camatopsis and Chasmocarcinops. A, Camatopsis rubida, Andaman Sea: male 4.2 × 4.5 mm (ZMUC CRU 20539); B, Camatopsis rubida, Australia: male 8.3 × 8.5 mm (NMV J 54591); C, Camatopsis africana n. sp., Madagascar: holotype male 5.7 × 6.9 mm (MNHN-IU- 2010 - 1574); D, Camatopsis leptomerus n. sp., Philippines: holotype male 10.5 × 11.3 mm (NMCR); E, Camatopsis leptomerus n. sp., Philippines: paratype female 3.4 × 4.0 mm (ZRC 2015.159); F, Camatopsis minor n. sp., Indonesia: holotype male 3.6 × 4.3 mm (NNM-ZMA); G, Camatopsis thula n. sp., Taiwan: holotype male 8.9 × 9.3 mm (ZRC 1999.0662); H, Camatopsis valida n. sp., Fiji: holotype male 3.6 × 4.9 mm (MNHN-IU- 2013 - 9067); I, Chasmocarcinops gelasimoides, Andaman Sea: male 8.8 × 9.5 mm (PMBC 16849); J, Chasmocarcinops gelasimoides, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341).

FIGURE 39. Chelae of species of Camatopsis. A, B, C. leptomerus n. sp., Philippines: holotype male 10.5 × 11.3 mm (NMCR); C, D, C. leptomerus n. sp., Philippines: paratype female 3.4 × 4.0 mm (ZRC 2015.159); E, F, C. thula n. sp., Taiwan: holotype male 8.9 × 9.3 mm (ZRC 1999.0662); G, H, C. minor n. sp., Indonesia: holotype male 3.6 × 4.3 mm (NNM-ZMA); I, J, C. valida n. sp., Fiji: holotype male 3.6 × 4.9 mm (MNHN-IU- 2013 - 9067).

FIGURE 68. Gonopods and third maxilliped of Camatopsis leptomerus. A, Philippines: paratype male 4.7 × 5.9 mm (ZRC 2015.120); B ‒ D, Indonesia: male 2.5 × 3.9 mm (NNM-ZMA 241605 e), E, Philippines: paratype female 3.4 × 4.0 mm (ZRC 2015.159); F, Philippines: paratype male 3.1 × 3.4 mm (ZRC 2015.120); G, Philippines: paratype female 4.8 × 5.8 mm (ZRC 2015.154); H, Philippines: male 4.7 × 5.9 mm (ZRC 2015.120). A, B, ventral view of left G 1; D, dorsal view of left G 1; C, ventral view of distal part of left G 1; E, right third maxilliped (denuded); F ‒ H, left third maxilliped (denuded). Scales: A, B, D = 0.25 mm; E ‒ H = 0.5 mm; C = 0.01 mm.

FIGURE 69. Thoracic sternum, third maxilliped, pleon and gonopods of Camatopsis species. A, B, D ‒ F, C. minor n. sp., Indonesia: holotype male 3.6 × 4.3 mm (NNM-ZMA); C, C. minor n. sp., Indonesia: paratype male 3.4 × 4.0 mm (NNM- ZMA); G ‒ K, C. valida n. sp., Fiji: holotype male 3.6 × 4.9 mm (MNHN-IU- 2013 - 9067). A, anterior thoracic sternum; B, male pleon; C, D, H, I, ventral view of left G 1; E, J, dorsal view of left G 1; F, K, left G 2; G, left third maxilliped (setae not drawn). Scales: A, B, G = 0.5 mm; C – F = 0.25 mm; H – K = 0.1 mm.

FIGURE 86. Female thoracic sternum and pleon of species of Camatopsis and Chasmocarcinops. A, Camatopsis rubida, Australia: female 6.0 × 7.0 mm (NMV J 61082); B, Camatopsis africana n. sp., Mozambique Channel: paratype female 9.4 × 11.0 mm (MNHN-IU- 2008 - 10288); C, Camatopsis leptomerus n. sp., Philippines: paratype female 12.7 × 13.2 mm (ZRC 2015.170); D, Camatopsis thula n. sp., Taiwan: paratype female 7.1 × 7.6 mm (ZRC 2009.0348); E, Camatopsis minor n. sp., Indonesia: paratype female 4.0 × 4.9 mm (NNM-ZMA); F, Chasmocarcinops gelasimoides, Singapore: female 9.3 × 10.6 mm (ZRC 2013.1411).