Paratrypaea maldivensis ( Borradaile, 1904 ) Borradaile, 1904

Dworschak, Peter C., 2012, On the identities of Callianassa bouvieri Nobili, 1904, C. maldivensis Borradaile, 1904, and C. gravieri Nobili, 1905 (Crustacea: Decapoda: Callianassidae): a morphometric approach, Zootaxa 3149, pp. 39-56 : 50-52

Paratrypaea maldivensis ( Borradaile, 1904) n. comb.

Figs 1 F, 5J–T, 6K–U, 7C

Callianassa (Trypaea) maldivensis Borradaile, 1903: 546 (nomen nudum); 1904: 753, pl. 58, fig. 3b; Pearson, 1905: 66, 90; de Man, 1928a: 22 –23.

Callianassa cf. japonica — Dörjes & Cheng, 1986: 23 1(table 1), 233 (table 2), 236 (table 3) [not Callianassa japonica Ortmann, 1891 ].

Callianassa rectangularis Ngoc-Ho, 1991: 292, fig. 5 [type locality: Atoll Surprise, New Caledonia], (new synonym).

Callianassa bouvieri — Sakai, 1999: 40 (part), figs 6a,b; 2005: 78 (part) [not Callianassa bouvieri Nobili, 1904 ].

Callianassa cf gravieri — Dworschak, 2003: 424.

Paratrypaea rectangularis — Komai & Tachikawa, 2008: 36.

Gilvossius bouvieri — Sakai, 2011: 374 (part) [not Callianassa bouvieri Nobili, 1904 ].

Holotype. UMC I.58505, male (tl 17, cl 4.8), Hulule, Malé Atoll, Maldive Is., J.S. Gardiner coll. (= Callianassa bouvieri Nobili, 1904 , M. de Saint Laurent 1977) [in good condition, all legs except major P1 still attached, left mxp3 missing, abdominal somite 1 and telson slightly distorted].

Additional material. NHMW 25102–25104, 2 males, 1 female (cl 3.0–3.2), Red Sea, Jordan, Aqaba, RDC, 8– 28 m, P. Dworschak coll. 25–26 Oct. 2000. – ULLZ 8428, 1 male, ULLZ 8429, 1 female, NHMW 25108–25113, 2 males, 2 females, 2 ovigerous females (cl 3.0–4.5), Red Sea, Jordan, Aqaba, RDC, 4–19 m, P. Dworschak coll. 1– 12 November 2001. – NHMW 25105–25106, 1 female, 1 ovigerous female (cl 3.3, 4.2), Red Sea, Jordan, Aqaba, Murjan, 10–14 m, P. Dworschak coll. 7 Nov. 2001. – NHMW 25107, 1 female (cl 4.1) Red Sea, Jordan, Aqaba, Saudi Border, P. Dworschak coll. 11 November 2001. – NHMW 25114–25132, 6 males, 5 females, 8 ovigerous females (cl 2.6–4.0), Red Sea, Jordan, Aqaba, RDC, 11–22 m, P. Dworschak coll. 27 October – 7 November 2002. – ULLZ 8430, 1 ovigerous female, ULLZ 8431, 1 ovigerous female, NHMW 25133–25156, 5 males, 6 females, 13 ovigerous females (cl 2.5–4.9), Red Sea, Egypt, Dahab, Laguna, 10–13 m, P. Dworschak coll. 21–29 October 2005. – NHMW 25157, 1 ovigerous female (cl 3.4), Red Sea, Egypt, Dahab, Islands, 13 m, P. Dworschak coll. 24 October 2005. – SMF 40674, 1 female (tl 8, cl 1.85), Rotes Meer, Shab Baraja Reef, N-lich Port Sudan, U-13 (20° 52.5' N 37° 23' E) 12 m Tiefe, L. Karbe coll. Oktober 1977. – SMF 23869 1 juvenile (tl 7.7 cl 1.7, left P1 missing) Taiwan, Nord-Insel, vor Tung-hsiao, Feinsand, 5 m, J. Doerjes leg. 18 October 1981. – SMF 23871 1 female (tl 8.5 cl 1.85, all pereopods and Mxp3 missing), 1 abdomen, 3 detached left P1, Taiwan, Westküste, vor Tai-shi, Südprofil, Feinsand, 11 m, J. Doerjes leg. 7 October 1981. – SMF 23872 1 female (tl 6.9 cl 1.46, all pereopods and mxp3 missing), Taiwan, Westküste, vor Tai-shi, Südprofil, Feinsand, 20 m, J. Doerjes leg. 7 October 1981. – NTOU A01224 , 1 ovigerous female (tl 23.8 cl 4.6, left P1 missing), Taiwan, Pingtung County, Houpihu, 18 m, P. Dworschak coll. with yabby pump 25 July 2009. – NTOU A01225 , 1 female (tl 17.1 cl 3.9, bopyrid left), Taiwan, Pingtung County, Houpihu, 9.5 m, P. Dworschak coll. with yabby pump 25 July 2009. – MNHN Th-1069 male (tl 20, cl 4.5) Nouvelle Caledonie, Atoll de Surprise St. 446, 36 m, 18°19'S 163°04'E, B. Richer-ORSTOM coll. (holotype of Callianassa rectangularis Ngoc-Ho, 1991).

Description. Carapace 0.23 of total body length; rostrum spiniform, directed slightly downward, almost reaching to end of eyestalk. Anterolateral projection obtuse; anterolateral concavity moderately deep, with tiny cleft; dorsal oval well defined, smooth, cervical groove across about posterior 0.2 of carapace length; linea thalassinica extending to posterolateral margin of carapace.

Length ratio of first to sixth pleonal somites measured along midline 1.0: 1.52: 1.1: 0.95: 1.05: 1.5. First to fifth pleomere as in P. bouvieri . Sixth pleomere slightly longer than wide, rectangular in dorsal view, bearing shallow notches on posterior one-third; no ventrolateral projection. Telson subrectangular, slightly longer than wide; dorsal surface nearly flat; lateral margin with two spiniform setae on posterolateral corner, with short transverse suture subproximally; posterior margin generally convex, but with faint median concavity, median tooth prominent ( Fig. 7 C).

Eyestalks, antennulae, antennae, epistome, sternal shield on seventh thoracic somite and mouthparts as in P. bouvieri (see above).

Third maxilliped without exopod; ischium-merus operculiform, 1.5 to 1.9 times as long than wide, with dense setation on ventral margin; ischium longer than broad, distinctly widened distally, crista dentata consisting of row of small acute spines arranged in sinuous row on midline; merus about 1.5 times wider than long, distinctly shorter than ischium, unarmed on distomesial margin, ventrodistal angle not produced; carpus longer than wide, subequal in length to merus; propodus about twice as long than wide, slightly longer than carpus; dactylus slender, digitiform, shorter than propodus.

Chelipeds (first pereopods) greatly dissimilar in males ( Fig. 2 C), similar in females ( Figs 2 D).

Male major cheliped ( Fig. 5 J, N, R) located on either right or left side of body (all males: 6 left, 10 right) constant in length, armament and setation of dactylus. Ischium moderately slender, becoming wider distally in general contour, dorsal margin sinuous, unarmed; lateral surface convex; ventral margin with row of 3–5 small teeth. Merus subequal in length to carpus; dorsal margin sinuous and smooth; lateral surface generally convex, ventral half forming shallow concavity accommodating proximal part of carpus; mesial surface slightly concave in general; ventral margin variable with 3 to 5 strong teeth in proximal half (see Fig. 6 K–P). Carpus semicircular, dorsomesial and ventromesial margins sharply ridged, lower edge smooth or serrated proximally, upper edge triangular in dorsal view, denticulated proximally ( Fig. 5 L, P); lateral surface smooth, convex; mesial surface medially convex, margins strongly upturned. Palm with dorsal and ventral margin parallel or slightly diverging proximally, 1.0–1.5 times as long as wide; lateral surface smooth, convex; with blunt palmar process; mesial surface convex medially, without sculpture or armament, margins somewhat upturned, dorsomesial and ventromesial margins sharply ridged, upper smooth, lower denticulated proximally ( Fig. 5 K, O). Fixed finger 0.7 to 1.0 length of palm, about as long as dactylus, nearly straight to noticeably curved, terminating in subacute tip; cutting edge unarmed; lateral surface convex, with tuft of long setae proximally on cutting edge; ventral margin with several setae. Dactylus subequal in length to or shorter than palm, weakly hooked, terminating in acute or subacute tip; dorsal and lateral surfaces occasionally with mat of dense, soft setae; cutting edge with 2 or 3 molar-like teeth.

Male minor cheliped ( Fig. 5 M, Q, S) rather slender, about 0.8–0.9 length of major cheliped, uniform in shape. Ischium with margins unarmed; dorsal margin nearly straight; ventral margin weakly concave to straight, unarmed. Merus varying from shorter to slightly longer than carpus; dorsal margin convex, unarmed; lateral surface weakly convex, smooth; ventral margin with one spine at midlength. Carpus about two times as long as high; dorsal and ventral margins bluntly ridged, smooth, with row of short setae. Palm as long as high or slightly longer than high; dorsal margin bluntly ridged, smooth; ventral margin sharply ridged, with row of tufts or individual setae; lateral and mesial surfaces weakly convex, smooth. Fixed finger triangular, terminating in acute tip; cutting edge with small denticles. Dactylus longer than palm, as long as fixed finger, terminating in acute tip; dorsal margin rounded, with row of tufts of setae; cutting edge with small denticles; hiatus between fingers prominent.

Both female chelipeds ( Fig. 5 T, U) similar to minor male chelipeds.

Second to fifth pereopod similar to those of P. bouvieri (see above).

First and second pleopods absent in males. Female first and second pleopods, third to fifth pleopods and uropods similar to those of P. bouvieri .

Size. Males from 2.6 to 4.8 mm cl, females from 1.85 to 4.8 mm cl (ovigerous females from 2.8 to 4.2 mm cl).

Colour. Transparent with a touch of red dorsally on chelipeds, red chromatophores dorsally on abdomen. Females much darker coloured than males ( Fig. 1 F).

Parasites. In Dahab, two females had an unidentified bopyrid in the gill chamber; in Aqaba, three females and one male were parasitised by an unidentified cryptoniscid.

Habitat. Recent samples were collected exclusively sublittorally from fine sands or sand troughs between patchy corals in depths between 4 and 20 m. In Aqaba, this species occurred together with Callianassa aqabaensis and Thomassinia gebioides de Saint Laurent, 1979 in fine sand between the large mounds and funnels of Glypturus laurae de Saint Laurent (in de Vaugelas & de Saint Laurent, 1984). Burrow openings, which cannot be differentiated from those of C. aqabaensis , are characterised by one small mound and two small funnels nearby ( Fig. 1 E). Density was relatively low and did not exceed an estimated 40 individuals m -2 for both callianassids.

Distribution. Red Sea (this study); Maldives (type locality); Sri Lanka ( Pearson, 1905), Taiwan ( Sakai 1999 as C. bouvieri ; this study); New Caledonia (type locality of C. rectangularis ).

Remarks. Males of P. m a l d i v e n s i s are rather rare. In Aqaba (2000, 2001 and 2002 collections pooled) the male: female ratio was 1:2.1. In Dahab, this ratio was 1:4.4 for all specimens collected and preserved and was even higher because not all females retrieved with the yabby pump were taken because of export limitations. Of the females from Aqaba, 47% were ovigerous; this percentage was 63% in Dahab.

Figures

FIGURE 1. Paratrypaea bouvieri (A – D) and P. maldivensis (E, F), habitat (A, B), burrow openings (C, E) and live specimens (D, F). A, C, Dahab, El Qura; B, mangrove at Shura Arwashi near Nabq; D, male specimen (NHMW 25048, cl 6.8) from Dahab; E, sediment surface in 10 m depth at " Laguna " (photograph: Philip Hofer); F, male (top, NHMW 25115, cl 3.9) and female (bottom, NHMW 25125, cl 3.6) specimen from Aqaba. Scale is 5 cm in C and E, 1 cm in D and F.

FIGURE 2. Plots of propodus height of major (phma, filled symbols) and minor (phmi, open symbols) chelipeds of males (A, C, squares) and females (B, D, circles) of P. bouvieri (A, B) and P. maldivensis (C, D). Triangles represent data for the holotypes of C. bouvieri and C. maldivensis, inverted triangles data for holotypes of C. gravieri and C. rectangularis.

FIGURE 5. Paratrypaea bouvieri (A – I) and P. maldivensis (J – U), major and minor chelipeds. A – D, MNHN Th- 65 (male holotype of C. bouvieri, cl 5.3); E, MNHN Th- 79 (female holotype of C. gravieri, cl 3.8, minor cheliped only); F, G, NHMW 6591 / 2 (male cl 4.4); H, I, NHMW 6591 / 15 (ovigerous female cl 5.2); J – M, UMC I. 58505 (male holotype of C. maldivensis, cl 4.8); N – Q, MNHN Th- 1069 (male holotype of C. rectangularis, cl 4.5); R, S, NHMW 25120 (male cl 3.5); T, U, NHMW 25128 (female cl 4.0). Mesial aspects except H, I, M; B, K, N, lower border of propodus in dorsomesial view; C, L, O, carpus in dorsal view. Most setation omitted. Scale is 1 mm.

FIGURE 6. Outline of selected major cheliped merus in mesial view (partially mirrored for uniform orientation). A – E, P. b o u - vieri males; F – J, P. bouvieri females; K – P, P. maldivensis males; Q – U, P. maldivensis females. A, NHMW 25098; B, NHMW 25086; C, NHMW 19829; D, NHMW 25076; E, NHMW 19983; F, NHMW 6591 / 24; G, NHMW 25050; H, NHMW 25073; I, NHMW 25085; J, NHMW 19980; K, NHMW 25135; L, NHMW 25102; M, ULLZ 8428; N, NHMW 25120; O, MNHN Th- 1069 (holotype of C. rectangularis); P, UMC I. 58505 (holotype of C. maldivensis); Q, NHMW 25117; R, NHMW 25107; S, NHMW 25129; T, NHMW 25128; U, NHMW 25105. Scale is 1 mm. Numbers to the left indicate carapace length of the respective specimen in mm.

FIGURE 7. Posterior border of telson. A, no median spine (P. bouvieri, NHMW 25076, male cl 5.3); B, tiny median spine (P. bouvieri, NHMW 25065, male cl 6.6); C, prominent median spine (P. maldivensis, NHMW 25145, female cl 4.4). Scale is 100 µm.