Sadayoshia moorei, Macpherson, Enrique & Baba, Keiji, 2012

Macpherson, Enrique & Baba, Keiji, 2012, The squat lobsters of the genus Sadayoshia Baba, 1969 (Crustacea: Decapoda: Anomura: Munididae): new records including six new species from the Pacific Ocean, Zootaxa 3589, pp. 30-48 : 41-43

Sadayoshia moorei n. sp.

( Figs. 5 , 7 E, 8B)

Material examined. Holotype: French Polynesia, Society Islands, 17º30.87’S, 149º45.70’W, 20 m, 23 October 2008: ov. Ƥ 4.1 mm (UF16050).

Etymology. This species is dedicated to the Moore family for their enormous dedication and generous support to marine conservation worldwide.

Description. Carapace: As long as broad; dorsal surface nearly horizontal from anterior to posterior; cervical groove distinct. Dorsal surface with 3 pairs of epigastric spines, 1 parahepatic, 1 anterior branchial and 1 postcervical spine on each side; ridges with numerous short setae and scattered long iridescent setae. Gastric region with 8 transverse ridges behind epigastric spines: first, third and fifth interrupted and scale-like, others uninterrupted. Mid-transverse ridge of carapace interrupted, preceded by cervical groove; lateral part of posterior branchial region with 7 ridges (exclusive of mid-transverse ridge and posteriormost transverse ridges directly anterior to posterior margin of carapace). Lateral margins slightly convex, with 7 spines. Rostrum horizontal in lateral view, 1.4 times as long as broad, length 0.7 that of carapace; rostral spine nearly 4.0 times longer than wide (measured at sinus between rostral and anterior lateral spines), dorsal surface strongly carinated in midline, with short setae along each side of dorsal carina; lateral margin with anterior pair of spines lanceolate and dorsally flatish. Pterygostomian flap rugose with sparse setae, anterior margin ending in blunt point.

Sternum: Sternal plastron 0.8 times as long as broad, lateral limits divergent posteriorly. Sternite 3 1.5 times broader than long, anterior margin strongly convex, with small but distinct median notch. Sternite 4 2.1 times longer and 3.8 times broader than preceding sternite, 0.4 times as long as broad. Surface of sternites 4–6 with 2 or 3 transverse ridges each flanking midline. Lateral parts of sternite 7 with a few granules.

Abdomen: Somite 2 having anterior transverse ridge with 2 distinct submedian spines; somites 2–3 with 3 additional uninterrupted or interrupted ridges.

Eyes: Ocular peduncles short; cornea dilated, maximum corneal diameter about 0.4 times distance between bases of anterolateral spines; eyelashes long, reaching midlength of cornea.

Antennule: Article 1 with 4 distal spines: mesial smaller than medioventral and mediodorsal, lateral spine clearly longer than others; lateral margin unarmed; ventral surface with a few short scales.

Antenna: Article 1 with distomesial spine nearly reaching distal margin of article 2. Article 2 with distolateral spine longer than distomesial spine, terminating in midlength of article 3. Articles 3 and 4 unarmed.

Mxp 3: Ischium with well-developed distal spine on flexor margin; extensor margin unarmed; crista dentata with 30 denticles. Merus subequal in length to ischium, with 3 strong spines on flexor margin, proximal 2 subequal in size and larger than distal spine; extensor margin unarmed. Carpus unarmed.

P1: Twice carapace length, relatively stout; with numerous long uniramous iridescent setae along lateral and mesial margins of merus, palm and fingers; dorsal and ventral surfaces of palm and fingers with scales bearing short setae. Merus 0.8 times length of carapace, 3.4 times as long as carpus, with strong distal spines on lateral and mesial margins, and a few additional spines on distal part of dorsal surface. Carpus as long as broad, with spines on dorsal and lateral surfaces and well-developed spines on mesial margin. Palm 1.3 times longer than broad; with dorsolateral and mesial rows of spines continued on to entire margins of fixed and movable fingers, respectively; dorsal surface with row of spines in midline. Fingers slightly longer than palm, distally spooned.

P2–4: Relatively slender, somewhat compressed mesio-laterally, sparsely with long, uniramous, iridescent setae, and short plumose setae. Meri successively shorter posteriorly; P2 merus 0.8 length of carapace, 3.4 times as long as broad, 1.3 times longer than P2 propodus; P3 merus 3.4 times as long as broad, 1.2 times length of P3 propodus; P4 missing; dorsal margins with row of proximally diminishing spines on P2 and P3; ventrolateral margins with a few spines, terminal spine strong. Carpi with 3 spines on extensor margin, distalmost largest; flexor margins with distal spine; lateral side with 1–4 small spines. Propodi nearly subequal in length, 4.0–4.4 times as long as broad; extensor margin unarmed; 0–2 spines on each lateral side; flexor margin with 8–9 slender movable spines. Dactyli subequal in length, 0.6–0.7 times length of propodi, ending in incurved, strong, sharp spine; flexor margin with 5 or 6 seta-like movable spines, each arising from low tooth.

Colour: Rostrum and lateral spines reddish. Carapace transversely whitish between second and fourth lateral spines and behind last lateral spines; transversely brownish between base of rostrum and second lateral spines and behind fourth lateral spines; ridges reddish brown. Abdomen brownish, tergite 2 laterally whitish. P1 pale brown, with dark spots on merus and carpus (with dorsal spines basally dark, distally whitish); fingers dark brown on proximal half, whitish on distal half. P2–4 with whitish and brownish bands; meri with red spot on distal part of lateral side.

Remarks. The new species belongs to a group of species bearing two spines on the anterior ridge of the abdominal somite 2. The group contains three species: S. acroporae Baba 1972 , S. aludra n. sp. (see above) and S. moorei . The new species is readily differentiated from the congeners by the shape of the rostrum: the rostrum is dorsally carinate in S. moorei , whereas it is smoothly convex from side to side in S. acroporae and S. aludra .

Furthermore, Sadayoshia moorei is distinguished from S. aludra by the following: the anterior lateral spines of the rostrum are flattish and lanceolate, instead of spiniform and convex from side to side; the posterior branchial region laterally bears 7 instead of 10 ridges (excluding mid-transverse and posterior transverse ridges); the number of transvese ridges on the abdominal somites is 4 instead of 6.

The color patters are different between the new species and S. acroporae ( Fig 8A & 8 B; see also Macpherson & Baba 2010). Sadayoshia acroporae has the carapace and abdomen orangish or brownish and P2–4 with reddish or brownish bands, without red spots on meri. On the other hand, S. moorei has the carapace with two transverse whitish bands and P2–4 meri each with a red spot on the distolateral portion.

Distribution. French Polynesia, Society Islands, at 20 m.

Figures

FIGURE 5. Sadayoshia moorei n. sp., holotype, ovigerous female, 4.1 mm, French Polynesia, Society Islands (UF 16050). A, carapace and abdomen, dorsal view; B, sternal plastron, sternites 3 and 4; C, left cephalic region, showing antennular and antennal peduncles, ventral view; D, right Mxp 3, lateral view; E, right P 1, distal part, dorsal view; F, right P 2, lateral view; G, left P 3, lateral view. Scale: A, E – G = 1 mm; B – D = 0.5 mm.

FIGURE 7. Rostrum, dorsal view. A, Sadayoshia acamar n. sp., ovigerous female, 5.0 mm, Chesterfield Islands, CHALCAL 1984, Stn DC 45 (MNHN-IU- 2010 - 5378). B, S. actaea n. sp., holotype, female, 3.2 mm, Lifou Island. LIFOU, Stn 1467 (MNHN-IU- 2010 - 5372). C,. S. adaro n. sp., ovigerous female, 3.9 mm, Solomon Islands. SALOMON 1, Stn DW 1744 (MNHN-IU- 2010 - 5376). D, S. aludra n. sp., ovigerous female, 9.1 mm, Chesterfield Islands. CORAIL 2, Stn DW 106 (MNHN-IU- 2010 - 5353). E, S. moorei n. sp., holotype, ovigerous female, 4.1 mm, French Polynesia, Society Islands (UF 16050) F, S. savali n. sp., ovigerous female, 5.4 mm, Lifou Island, Stn 1450. Scale = 1 mm.

FIGURE 8. A. Sadayoshia acroporae Baba 1972, Philippines, PANGLAO Expedition, Stn B 36, 9 º 35.9 ’ N, 123 º 44.5 ’ E, 24 m, male, 2.8 mm, dorsal view. B. Sadayoshia moorei n. sp., French Polynesia, Society Islands, holotype, ovigerous female, 4.1 mm, dorsal view.