Raymunida vittata Macpherson, 2009

Osawa, Masayuki, 2012, Raymunida Macpherson & Machordom, 2000 (Crustacea: Decapoda: Anomura: Munididae) from the KUMEJIMA 2009 Expedition in the Ryukyu Islands, Japan *, Zootaxa 3367, pp. 134-144 : 140-143

Raymunida vittata Macpherson, 2009

( Figs. 3, 4B)

Raymunida vittata Macpherson, 2009: 446 , fig. 7.

Material examined. 3 males (cl 7.2–10.5 mm), 3 females (cl 4.4–7.6 mm), St. Trawl 70, 26° 23.831 –23.590´N, 126° 45.685 –45.212´E, 95.5–123.0 m, dead coral blocks and rubble, trawl, 19 November 2009 (RUMF-ZC-1417) .

Diagnosis. Carapace ( Fig. 3A) longer than broad; 5 pairs of epigastric spines; 1 parahepatic, 1 or 2 branchial anterior, and 1 postcervical spines on each side; frontal margin with small spine lateral to lateral limit of orbit. Rostrum 0.4 cl; supraocular spines 0.6 length of rostrum. Thoracic sternites 5 and 6 ( Fig. 3B) with short oblique ridges on lateral parts. Abdominal somite 2 ( Fig. 3C–F) with uninterrupted long stria or row of short striae between two distinct transverse ridges on dorsal surface; somite 3 with or without some short or very short striae between two distinct transverse ridges on dorsal surface; somite 4 without striae. Antennal article 1 ( Fig. 3G–J) with mesial spine usually reaching or slightly overreaching distal margin of article 4 but never reaching distal margin of basal article of antennular peduncle; article 2 usually with subdistal spine on mesial margin; article 3 bearing small but distinct spine on distomesial margin. Mxp3 merus with distinct spine on dorsodistal margin. P1 ( Fig. 3K) chela relatively slender, 4.9–7.7 times length of breadth measured on base of fingers, with dorsolateral row of spines interrupted in proximal half to three fourths; fingers 1.3–1.8 times longer than palm, each with rounded longitudinal crest along dorsal midline; dactylus with 3 spines on proximomesial margin. P2–4 subequal on P2 and 3, shorter on P4; merus with irregular row of 10–12 (P2), 5 (P3), and 3 or 4 (P4) spines on dorsal margin, lateral surface with another irregular row near dorsal margin on P3 (8–10 spines) and P4 (7 or 8 spines) but unarmed on P2, lateral ventrodistal margin with 4 or 5 (P2), 2 or 3 (P3), and 1 or 2 (P4) spines (if present, including submarginal spines); mero-carpal articulation of P4 overreaching lateral end of anterior cervical groove but not reaching frontal margin of carapace; carpi with 5 (P2), 4 or 5 (P3), and 1 or 2 (P4) spines on dorsal margin; propodi with 5 or 6 ventral corneous spines including distal paired spines; dactyli with 4–6 corneous spines on ventral margin.

Colouration in life ( Fig. 4B). Carapace, abdomen, and P1 generally bright red. Carapace with white bands on anterior margins of transverse ridges; lateral portions white. Pterygostomian flap dark red, with relatively broad white area along dorsal margin. Abdomen with some small, dark red marks; somites 2–4 each with narrow white band on anterior margin of posterior transverse ridge. P1 pale coloured on dorsal subdistal part of each merus and dorsal median part of each carpus; palm with broad white ring on subdistal part (ring replaced by cluster of white spots in large specimens); fingers each with white ring on distal one third to half. P2–4 generally reddish on meri and carpi and orange on propodi and dactyli; meri with irregular white marks on lateral surface; carpi with narrow orange stripes on lateral surface.

Distribution. Previously known only from Vanuatu. The present specimens greatly extend the distribution range of R. vittata to the northern hemisphere.

Habitat. The present specimens were collected from substratum of dead coral blocks and rubble. The type specimens from Vanuatu were collected at the depths ranging from 32 m to 118 m. The present specimens were obtained from 95.5–123.0 m .

Remarks. Macpherson (2009) described that the antennal article 3 of R. vittata is unarmed, but his figure (fig. 7C) shows a small spine on the distomesial margin of the article. The present specimens also have such a spine. The fixed finger of the P1 was described and illustrated by Macpherson (2009) to have a row of spines on the entire dorsolateral margin. However, the dorsolateral row of spines interrupts in the proximal half to three fourths in the present specimens. The both fingers of the P1 also have a rounded longitudinal crest along the dorsal midline in the present material. This agrees with the figure by Macpherson (2009, fig. 7E).

There are some intraspecific morphological variations in the present specimens. The mesial spine of the antennal article 1 reaches the distal margin of the peduncular article 4 in the present specimens except for the smallest female (cl 4.4 mm), in which the mesial spine only overreaches the distal margin of the peduncular article 3. Macpherson (2009) described that the spine in the small paratypes of R. vittata only reaches the distal margin of the antennal peduncle, unlike exceeding that margin in other larger types. The smallest female paratype and the present smallest female agree to each other in the specimen size (cl 4.4 mm), but the mesial spine of the antennal article 1 is shorter in the present specimen than the paratype. The subdistal spine on the mesial margin of the antennal article 2 is distinct in large specimens examined (two males, 10.2, 10.5 mm; female, 7.6 mm), but it is reduced to a small low protuberance in other small specimens (male, cl 7. 2 mm; two females, cl 4.4, 6.3 mm). The P1 fingers are 1.3–1.8 (mean 1.6) times longer than the palm, and comparatively shorter in two large males than in other smaller specimens. The striae of the dorsal surface of the abdominal somites 2 and 3 are also variable. The somite 2 lacks any striae between two distinct transverse ridges in the smallest female (cl 4.4 mm), but it has an uninterrupted long stria or a row of some short striae in other larger specimens. The somite 3 lacks any striae between two distinct transverse ridges in three small specimens (one male, cl 7.2 mm; two females, cl 4.4, 6.3 mm), but it possesses some short or very short striae in other large specimens.

Raymunida vittata was discriminated from R. lineata by the striation on the abdominal somites 2–4, relative length of the P1 fingers, and fresh colouration ( Macpherson, 2009). Although the less developed striae on the abdominal somites 2–4 and comparatively shorter fingers of the P1 generally distinguish R. vittata from R. lineata , examination of the present specimens revealed that the two morphological distinctions somewhat vary as mentioned above. Raymunida vittata is more clearly different from R. lineata by the striation on dorsal surface of the abdominal somites 3 and 4. The abdominal somite 3 has no striae or a row of some, short or very short striae in R. vittata , whereas it usually possesses a long continuous stria (rarely interrupted in the median part) in R. lineata . The abdominal somite 4 lacks striae in R. vittata , but it bears two moderately long striae or a row of several short striae in R. lineata . Fresh colouration is also very different between the two species (see Osawa 2005; Macpherson 2009; present study).