Macrothea bouchardi, Macpherson, Enrique & Cleva, Régis, 2010

Macpherson, Enrique & Cleva, Régis, 2010, Shallow-water squat lobsters (Crustacea, Decapoda, Galatheidae) from Mayotte (Comoros Island), La Réunion and Madagascar, with the description of a new genus and two new species, Zootaxa 2612, pp. 57-68 : 63-67

Macrothea bouchardi new species

( Figs. 2 , 3 K)

Material examined. Mayotte. Stn 23, Choizil pass, "Patate à Teddy", 12°40'56.91"S, 44°57'51.63"E, 15–30 m, J.-M. Bouchard, V. Dinhut, J. Dumas coll., 13 November 2009, outer reef, collapsed barrier, 1 M 3.5 mm, holotype (MNHN-Ga7350).

Madagascar. Antimo Vatae Cruise, Stn 3572, 25º11.63’S, 47º11.61’E, 75–77 m, 0 8 May 2010: 1 M 5.0 mm, paratype (MNHN-Ga 7467).

Description. Carapace, exclusive of rostrum, 1.2 times as long as wide; dorsal surface nearly horizontal from anterior to posterior, with numerous short transverse ridges and some scattered short fine setae; cervical groove barely distinct, laterally bifurcated; row of 12–14 spines in 6 or 7 pairs arranged in concentric arc along epigastric and hepatic regions; 1 additional hepatic spine behind anterolateral spine and some small protogastric spines in paratype specimen. Rostrum triangular, 1.2 times as long as broad, length 0.5 postorbital carapace length and breadth 0.4 that of carapace, slightly deflexed anteriorly; dorsal surface concave, with several fine setae; lateral margin with 4 deeply incised sharp teeth, ventrally convex. Orbital margin oblique, lateral extremity unarmed; infraorbital margin smooth. Lateral margins convex, diverging on posterior half, with 6 spines: 1 spine in front of and 5 spines behind anterior cervical groove; first anterolateral, distinctly posterior to lateral limit of orbit; 2 spines on anterior branchial margin, anterior one distinctly larger than posterior one, and 3 small spines on posterior branchial margin, last very small.

Pterygostomian flap smooth, with few short ridges, anterior margin ending in acute spine.

Sternal plastron as long as wide, lateral extremities gently divergent posteriorly. Sternite 3 1.5 times as broad as long, anterior margin convex, with minute dentitions. Sternite 4 3.8 times longer and 3.7 times broader than sternite 3, 0.7 as long as broad; surface with a few short setiferous ridges. Following sternites smooth.

Abdominal somites 2–4 each with 2 transverse ridges on tergite; somite 5 with 1 scale-like ridge; tergite of somite 6 smooth, posteromedian margin nearly transversal. Telson 0.8 as long as broad, subdivided in 7 plates.

Ocular peduncles 1.4 times longer than broad; eyestalk (other than cornea) with lateral margin straight, dorsal anterior extension with stiff setae; cornea not dilated.

Basal article of antennular peduncle with well-developed distodorsal and distolateral spines; distomesial spine well-developed, slightly smaller than others. Ultimate article with a few short fine setae not in tuft on distodorsal margin.

Antennal peduncle having article 1 with ventral distomesial spine overreaching distal margin of article 2. Article 2 with well-developed distomesial spine, distolateral spine clearly smaller than distomesial spine and not reaching midlength of article 3. Article 3 with small distomesial spine in paratype specimen. Article 4 unarmed.

Mxp3 basis unarmed. Ischium with small distal spine on flexor margin; extensor margin unarmed; crista dentata with 24–30 denticles. Merus shorter than ischium; flexor margin with 2 strong spines of subequal size, proximal one located at midlength, distal one at terminal end; extensor margin unarmed. Carpus unarmed.

P1 2.9 times postorbital carapace length, relatively stout, subcylindrical, somewhat depressed on palm, and spinose, with sparse long setae. Merus 0.9 times length of carapace, 1.5 times as long as carpus, with some spines scattered on dorsal and mesial surfaces, distal spines prominent. Carpus 0.8 length of palm, 1.9 times as long as broad; dorsal surface with spines; mesial margin with 1 strong median spine. Palm 2.2 times longer than broad, lateral and mesial margins subparallel; some spines on dorsal surface; mesial margin with some spines; dorsolateral row of larger spines continued on to whole lateral margin of fixed finger. Fingers as long as palm, each distally ending in incurved spine; opposable margins nearly straight, with blunt serration; mesial and dorsal margins of movable finger with some proximal spines.

P2–4 stout, with long sparse setae. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.6 length of P3 merus); P2 merus 0.6 times carapace length, 3.0 times as long as broad, 2.3 times longer than P2 propodus; P3 merus 3.5 times longer than broad, 2.0 times longer than P3 propodus; P4 merus 2.6 times as long as broad, 1.2 length of P4 propodus; dorsal margins with row of proximally diminishing small spines on P2–3, unarmed on P4; dorsolateral surface unarmed on P2–4; ventral margin with row of well-developed spines on P2–3, unarmed on P4. Carpi with 2–5 small spines on extensor margin on P2–3, unarmed on P4; dorsolateral surface rugose; flexor margin with 2 distal spines on P2–3, unarmed on P4. P3 propodus as long as P2 propodus and slightly longer than P4 propodus, each 2.4–2.5 times as long as broad; extensor margin with several acute scales, not true spines, on proximal half on P2 and P3, unarmed on P4; flexor margin with 5 or 6 movable spines, each paired with another spine mesial to it, on P2–3; distal paired spines on P4. Dactyli subequal in length, sharply biunguiculate.

Epipods on pereiopods 1–3.

Coloration. Base of carapace, abdomen and pereiopods red. Base of rostrum and epigastric region white; abdominal somites with median wide white stripes. Eyestalks dorsally white and red. P1 with distal part of merus, proximal part of carpus and hand white; proximal part of fingers white. P2–4 with some white spots and stripes.

Etymology. The new species is dedicated to Jean-Marie Bouchard (head of the KUW company), who proposed to the Mayotte authorities and organized the expedition.

Distribution. Known from Mayotte, 15–30 m, and Madagascar, 75– 77 m.

Figures

FIGURE 2. Macrothea bouchardi new species, holotype, male, 3.5 mm, Mayotte, Stn 23 (MNHN-Ga 7350). A, carapace and abdomen, dorsal view; B, sternal plastron; C, telson and uropods, dorsal; D, left cephalic region, showing antennular and antennal peduncles, ventral view; E, right Mxp 3, lateral view; F, right P 1, dorsal view; G, right P 2, lateral view; H, right P 3, lateral view; I, right P 4, lateral view; J, right P 5 palm and fingers, lateral view. Scale, 1 mm.

FIGURE 3. A, Galathea aegyptiaca Paul’son, 1875, Madagascar, Nosy Be, ov. F 3.6 mm (UF 14013), dorsal view. B, Galathea aegyptiaca Paul’son, 1875, Madagascar, Nosy Be, M 3.0 mm (UF 14576), dorsal view. C, Galathea mauritiana Bouvier, 1914, Madagascar, Nosy Be, ov. F 3.6 mm (UF 14334), dorsal view. D, Galathea mauritiana Bouvier, 1914, Mayotte, ov. F 3.2 mm (MNHN-Ga 7335), dorsal view. E, Galathea denticulata new species, Mayotte, holotype, M 2.2 mm (MNHN-Ga 7338), dorsal view. F, Galathea spinosorostris Dana, 1852, Mayotte, M 3.2 mm (MNHN-Ga 7340), dorsal view. G, Galathea tanegashimae Baba, 1969, Madagascar, Nosy Be, M 3.8 mm (UF 14413), dorsal view. H, Galathea tanegashimae Baba, 1969, Mayotte, ov. F 3.7 mm (MNHN-Ga 7342), dorsal view. I, Galathea ternatensis De Man, 1902, Madagascar, Nosy Be, F 4.0 mm (UF 12554), dorsal view. J, Galathea ternatensis De Man, 1902, Madagascar, Nosy Be, F 3.4 mm (UF 14630), dorsal view. K, Macrothea bouchardi new species, Mayotte, holotype, M 3.5 mm (MNHN-Ga 7350), dorsal view. L, Sadayoshia edwardsii (Miers, 1884), Mayotte, M 4.6 mm (MNHN-Ga 7351). Photographs: Madagascar, G. Paulay; Mayotte, J. Poupin & R. Cleva.