Raymunida iranica, Osawa & Safaie, 2014

Osawa, Masayuki & Safaie, Mohsen, 2014, Two squat lobster species (Crustacea: Decapoda: Anomura) from the Persian Gulf, with description of a new species of Raymunida Macpherson & Machordom, 2000, Zootaxa 3861 (3), pp. 265-274 : 266-273

Raymunida iranica n. sp.

( Figs. 1 B, 2–4)

Material examined. North of Lavan Island, Hormozgan Province, Iran, Persian Gulf, 26°54' N, 53°21' E, 30–50m depth, bottom trawl, 14 December 2011, coll. K. Khajehnoori, holotype, female (cl 12.2 mm), FHU .

Description. Carapace ( Fig. 2 A, B), excluding rostrum, about 1.1 times longer than wide. Dorsal surface nearly horizontal from anterior to posterior, somewhat convex from side to side; main transverse ridges interrupted or uninterrupted; secondary transverse striae few; most ridges with dense, short plumose setae anteriorly; spines occasionally bearing single short simple seta at base. Gastric region slightly elevated, with row of 6 pairs of epigastric spines, mesial-most spine of each pair located slightly anterior to other spines. Cervical grooves distinct. One parahepatic spine, 2 (right) or 3 (left) branchial anterior spines, and 1 postcervical spine present on each side. Anterior branchial region between cervical and transverse grooves with short, transverse or obliquely transverse ridges. Posterior branchial region with 6 main transverse ridges (excluding posterodorsal ridge) and few short striae between main ridges; right side with low protuberance and main ridges partially interrupted. Cardiac region with 6 transverse ridges, first and sixth ridges interrupted but second to fifth ridges uninterrupted medially, second and fifth ridges extending to lateral marginat least on left side. Intestinal region with short transverse ridge medially; posterodorsal ridge somewhat elevated, followed by distinct secondary stria. Frontal margins slightly oblique, with 1 (left) or 3 (right) small spinesmesial to anterolateral spine.Lateral margins slightly convex in general outline and widest on posterior branchial regions, each with 6 spines (2 spines in front of and 4 spines behind cervical groove): first spine anterolateral, located slightly posterior to level of orbit, slightly overreaching level of frontal margin; second spine at midlength between first and third (first branchial) spines, distinctly smaller than anterolateral spine; third and fifth spines located directly posterior to lateral ends of cervical and transverse grooves, respectively; fourth spine accompanying another small spine anteroventrally; sixth spine small.

Rostrum ( Fig. 2 A, B) spiniform, 0.4 carapace length, arched in lateral view; dorsal surface with blunt carina proximally; lateral margins with few short simple setae, minutely crenulate distally. Supraocular spines ( Fig. 2 A, B) slightly exceeding midlength of rostrum and distal margins of corneas, subparallel; distal part slightly curved ventrally in lateral view; lateral margins unarmed (right) or with spinule (left) on median part; small spine present dorsally near base of each supraocular spine.

Orbits ( Fig. 2 A) shallow; lateral angle not produced, unarmed; ventral margin produced anteriorly, with small denticles on ventral margin ( Fig. 3 A).

Pterygostomial flaps ( Figs. 2 B, 3A) each with row of granules on anterior dorsal margin; anterior margin rounded; lateral surface with short and long, sinuous, longitudinal ridges.

Epistomal ridges ( Fig. 3 A) slightly sinuous, feebly granulate, each reaching anterior to excretory pore of article 1 of antennal peduncle; mesial protuberance obsolescent.

Thoracic sternum ( Fig. 2 C) 1.2 times wider than long measured on midline, widest on sternite 7, depressed along midline. Sternite 33.9 times wider than long measured along midline, approximately as wide as anterior margin of sternite 4; anterior margin faintly granulate, with shallow median notch and small projection at each lateral angle; lateral margins slightly convergent posteriorly. Sternite 4 entirely contiguous toposterior margin of sternite 3; surface with 2 long, transverse, granulate striae, anterior stria interrupted medially; anterior margin slightly concave, subequal in width to sternite 3. Sternites 5 and 6 with 2 and 1 pairs of very short, oblique striae on lateral parts, respectively. Sternite 7 smooth. Transverse ridges dividing sternites 5–7 obtuse, feebly granulate, each with row of short plumose setae.

Pleon ( Fig. 2 D, E) with 2 weak, transverse ridges on pleomere 1, posterior ridge somewhat lobed at each lateral end; pleomeres 2–6 tergites with 2 distinct, long transverse ridges bearing dense, short plumose setae on anterior margins (some long, stiff simple setae also present on pleomeres 2–5); transverse ridges uninterrupted and somewhat elevated on pleomeres 2–5, but interrupted in median part and slightly arched on pleomere 6. Pleomeres 2–4 ( Fig. 2 D) each with row of interrupted transverse striae between 2 long ridges on tergite; striae much longer on pleomere 2, fewest and faintly marked on pleomere 4. Pleomeres 5 and 6 ( Fig. 2 E) without secondary striae, posteromedian margin of pleomere 6 flattish. Telson ( Fig. 2 E) 1.6 times wider than long measured on midline, incompletely divided into 7 plates; proximal median and proximal lateral plates well calcified, with strong transverse ridges; remaining 4 posterior plates weakly calcified partially, with short, scaly ridges; distal margin emarginated medially.

Eyes ( Fig. 2 A, B) moderately large; cornea slightly dilated, maximum diameter about 0.2 length of distance between mesial bases of anterolateral spines; eyelash consisting of short simple setae; stout simple seta present near distal margin of rounded dorsal extension of peduncle.

Basal article of antennular peduncle ( Fig. 3 A), excluding distal spines, about 0.2 carapace length, falling slightly short of distal margin of cornea, moderately stout, with sparse setae on margins; distal 2 spines unequal, mesial spine distinctly shorter than lateral spine; lateral margin with 2 spines, distal spine located proximal to base of distolateral spine and clearly overreaching it, proximal spine much smaller, and located distal to midlength of article and distinctly proximal to level of distal margin ofarticle.

Antennal peduncle ( Fig. 3 A) stout, not reaching distal cornea margin, with sparse short setae on surface.Article 1 with long distomesial spine slightly overreaching distal margin of article 4 and falling short of distal margin of antennular basal article; distolateral angle rounded. Article 2 with 2 distal spines subequal in length, barely reaching distal margin of article 3; mesial margin with small spine near base of distomesial spine. Article 3 with small spine at dorsal distomesial angle; distal margin feebly granulate. Article 4 unarmed.

Mxp3 ( Fig. 3 B) moderately slender. Basis bearing 8 denticles on mesial ventral margin. Ischium armed with strong spine at distoflexor angle; disto-extensor angle acutely produced, terminating in small spine; crista dentate with 30 denticles. Merus as long as ischium measured on flexor margin, notmarkedly narrowed distally; flexor margin with 2 large, slender spines subequal in size; extensor margin with small spine at distal end; lateral surface with short striae. Carpus with slender spine on distoflexor margin, disto-extensor angle slightly produced. Propodus and dactylus unarmed, somewhat convex on flexor surface. Exopod distinctly overreaching distal margin of merus.

Epipods present on Mxp3 and P1–3.

P1 ( Fig. 3 C, D) slender, 2.9 times carapace length, with numerous short, scaly or transverse ridges except on fingers; ridges anteriorly bearing short plumose setae, somewhat elevated on lateral surfaces of merus and carpus; sparse long, stiff simple setae also present, numerous on mesial margins of merus and carpus and mesial and lateral margins of chela. Ischium with minute spine on lateral margin. Merus about 0.9 carapace length, 1.8 times longer than carpus, with irregular row of spines along mesial and lateral margins on dorsal surface, mesial spines much larger, distomesial spine strongest; mesial face with 2 spines (distal larger than proximal) on median part of midline and row of proximally diminishing spines on ventral margin; lateral face with distal submarginal spine and row of proximally diminishing spines on distal half of ventral margin; ventral surface without spines. Carpus nearly equal in width from proximal to distal, 2.6 times longer than wide; dorsal surface flattened, with mesial and lateral rows of irregular, small but distinct spines; mesial surface with 2 spines (distal spine larger than proximal spine) on distal two-thirds of midline and irregular row of spines on ventral margin; lateral face dorsally with row of small spines; ventral surface; ventral surface with small submedian spine near ventromesial margin. Chela slender, 7.0 times as long as wide measured on base of fingers. Palm somewhat compressed, slightly widened distally, as long as carpus, 2.4 times longer than wide; dorsal surface with moderately large spine on distal margin and mesial and lateral rows of small but distinct spines; dorsolateral margin with row of spines continuing onto proximal 0.6 of fixed finger; ventrolateral margin with row of small spines; mesial surface also with row of small spines on midline; ventral surface with 2 small spines on proximal mesial part and single spine at base of dactylus. Fixed finger nearly straight in lateral view, distally curving and crossing with dactylus when closed, ending in moderately long corneous claw, with small subterminal spine laterally; dorsal and ventral surfaces each with blunt crest on proximal half of midline; opposable margin nearly straight, with triangular teeth interspersed by numerous smaller denticles. Dactylus 1.9 times as long as palm, nearly straight in lateral view, ending in curved, moderately long corneous claw, with small subterminal spine mesially; dorsomesial margin slightly crenulate, with 3 spines on proximal one third; dorsal surface with blunt crest on proximal half of midline; ventral face with very weak, rounded, longitudinal ridge proximally; opposable margin nearly straight, with row of small, subacute and blunt denticles. No distinct hiatus between dactylus and fixed finger.

P2–4 ( Fig. 4 A, F, H) moderately slender, somewhat compressed, with sparse long, stiff simple setae on margins; lengths decreasing posteriorly; P2 longest, 2.0 times carapace length, when anteriorly extended, overreaching level of midlength of rostrum by mero-carpal articulation; P4 barely reaching lateral end of cervical groove directly anterior to first branchial marginal spine of carapace by mero-carpal articulation. Ischia each with small spine near ventral angle of distolateral margin on P2 and 3, but unarmed on P4; mesial surface with small spine near dorsal angle of distal marginon P3 and 4, but unarmed on P2. Meri successively shortening posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 most slender, nearly equal in width from proximal to distal; P3 and P4 broadest at midlength; length-width ratio, 6.3 on P2, 4.4 on P3, 3.7 on P4; meruspropodus length ratio,1.4 on P2, 1.3 on P3, 1.1 on P4; P2 merus 0.8 carapace length; dorsal margin with row of short plumose setae, and with 14 spines on entire length of P2 ( Fig. 4 A), 4 spines on distal half of P3 ( Fig. 4 G) and only 2 distal spines on P4 ( Fig. 4 I); lateral surface with short transverse, scaly ridges bearing dense, short plumose setae (some long, stiff simple setae also present on P3 and P4); dorsolateral margin with row of 11 and 8 spines on P3 and P4 respectively ( Fig. 4 F, H), but unarmed on P2; lateral ventral margin distally with row of 4 or 5 spines on P2, 2 or 3 spines on P3 and 1 or 2 spines on P4 (if present, including submarginal spine on distal one third of lateral surface) followed by row of moderately long transverse ridges, spine at distal angle strongest; mesial ventral margin unarmed or with 1 small subdistal spine on P2 ( Fig. 4 B, E), always unarmed on P3 and P4. Carpi subequal on P2–4, 0.5–0.6 length of propodi; extensor margin with 5 spines on P2, 3 or 4 spines on P3, and only 1 distal spine on P4, spines on P2 strongest; disto-extensor angle rounded; distoflexor margin produced, with small spine; lateral surface with low, slightly crenulate crest dorsally along midline and few obliqueridges on flexor half. Propodi not tapering distally, longest on P2, shortest on P4; length-width ratio, 8.2 on P2, 7.1 on P3, 6.7 on P4; extensor margin unarmed; lateral surface slightly elevated on midline, with row of short transverse ridges and sparse, stiff simple setae; flexor margin with 7, 5, and 3 or 4 evenly spaced, slender corneous spines on P2–4respectively, terminal spine paired with another smaller spine mesial to it ( Fig. 4 C). Dactyli ( Fig. 4 D) nearly straight, 0.5–0.6 length of propodi on P2–4, with slightly curved distal claw; flexor margin with 6, 5 or 6, and 4 or 5 slender, proximally diminishing, corneous spines on P2–4 respectively, each spine arising from low process.

P5 chela elongate, with numerous, short simple setae on dorsal and ventral surfaces and with irregular row of curved, serrate setae mesially on ventral face of palm.

Female with 4 pairs of elongate pleopods on pleomeres 2–5, those on pleomeres 3–5 well developed. Coloration. In formalin preservative ( Fig. 1 B). Body and appendages generally reddish brown. Carapace with red marks on hepatic, gastric, cardiac regions and anterior mesial part of posterior branchial regions; lateral marginal parts each with narrow white line. Rostrum and supraocular spines red. Pterygostomial flaps white along dorsal margin, white part broadened below anterior branchial region; remaining ventral part red. Pleomeres1–4 each with 1 median red and 2 submedian white stripes on tergite; tergite 5 with 2 submedian red marks anteriorly and 1 median white blotch broadened posteriorly; tergite 6 with no distinct marks. P1 carpus and chela red; palm distally with broad white band interrupted by narrow red line on dorsal surface of left side and ventral surface of both sides; fingers each with white band on distal one third; bases of spines generally dark red. P2–4 meri each with narrow red band on distal one third and broad white band near distal margin of lateral surface; carpi also white on each distal part; propodi red with 3 white bands on proximal, median, and distal parts; dactyli generally red, each proximal part whitish.

Etymology. The new species is named after the region where it was obtained, Iran.

Remarks. The genus Raymunida contains 12 Indo-West Pacific species ( Baba et al. 2008; Macpherson 2009; Osawa, 2012). Only R. elegantissima ( De Man, 1902) and R. insulate Macpherson & Machordom, 2001 have been known from the Indian Ocean, although the specific identity of the specimens referred to R. elegantissima from the region partially requires confirmation (cf. Macpherson & Machordom 2001; Osawa 2005; Baba et al. 2008). Raymunida iranica n. sp. is the thirteenth species of the genus and third species from the Indian Ocean. The new species differs from all known congeneric species in having a small spine near the base of each supraocular spine and a spine ventral to the second branchial marginal spine of the carapace. Such spines have not been reported for any other species.

Raymunida iranica n. sp. is morphologically most closely allied to R. cagnetei Macpherson &Machordom, 2000 known from French Polynesia. Shared diagnostic characters are: first article of antennal peduncle with distomesial spine not reaching distal margin of basal article of antennular peduncle and second antennal article armed with a subdistal spine on mesial margin, merus of third maxilliped with a distal spine on dorsal margin, and mero-carpal articulation of fourth pereopod reaching at most to level of first branchial marginal spine of carapace. However, in addition to the characters of R. iranica n. sp. unique in the genus, the new species is distinguished from R. cagnetei by the following characters: 1) the second to fourth pleomeres have a row of interrupted striae between two distinct transverse ridges on each tergite, but the second and third pleomeres occasionally bear only two short median striae and the fourth pleomere lacks striae in R. cagnetei ; 2) the two flexor marginal spines on the merus of the third maxilliped is subequal in size, rather than unequal with the distal spine being longer than the proximal in R. cagnetei ; 3) the fingers of the first pereopod have a blunt crest on each dorsal midline, but such a crest is absent in R. cagnetei ; 4) the dactylus of the first pereopod is 1.9 times longer than the palm, instead of slightly more than 1.5 times in R. cagnetei ; and 5) the merus and propodus of the second pereopod are more slender, 6.3 and 8.2 times length of their respective width, instead of about 5 and 7 times in R. cagnetei (cf. Macpherson & Machordom 2000). Although the fresh coloration of Raymunida iranica n. sp. is unknown, the new species and R. cagnetei also clearly differ in the patternof white stripes and bands on the body and pereopods. The lateral margins of the carapace each has a narrow stripe and first to fourth pleomeres possess two submedian stripes in R. iranica n. sp., whereas there is a continuous, broad stripe on each lateral margin of the carapace and first to third pleomeres in R. cagnetei . The palm of the first pereopod possesses a distal band in the two species, but the band is much narrower in R. iranica n. sp. than in R. cagnetei . The fingers of the first pereopod also have a submedian band in R. iranica n. sp. unlike in R. cagnetei . The second to fourth pereopods bear the banded pattern of white and red in R. iranica n. sp., instead of being entirely red in R. cagnetei (see Poupin 1996: pl. 10, fig. d, as Munida elegantissima ; Macpherson & Machordom 2000).

Following the key to species of the genus Raymunida given by Osawa (2012), R. iranica n. sp. also resembles R. elegantissima , R. lineata Osawa, 2005 , and R. vittata Macpherson, 2009 , but differs in the mero-carpal articulation of the fourth pereopod barely reaching, instead of overreaching the lateral end of the cervical groove directly anterior to the first branchial marginal spine of the carapace. Additionally, coloration of the pereopods distinguishes the new species from R. lineata and R. vittata , particularly in having white bands on the carpi and propodi of the second to fourth pereopods, which are absent in the latter two species ( Osawa 2005, 2012; Macpherson 2009; Chan et al.2011: fig. 474C). Although Macpherson & Machordom (2001) noted the coloration of R. elegantissima based on the specimens available to them, their specimens, at least partially, do not represent the true species as discussed by Osawa (2005). Nevertheless, the Macpherson & Machordom’s (2001) specimens referred to R. elegantissima differ from R. iranica n. sp. in the distal parts of the cheliped fingers being whitish and ambulatory legs with only some small whitish spots.

Raymunida insulata , another congeneric species recorded from the Indian Ocean, is discriminated from R. iranica n. sp. by the absences of the following spines or striae: one to three spinules on the frontal margin mesial to the anterolateral spine of the carapace, striae between two distinct transverse ridges on the second and third pleomeres, a small subdistal spine on the mesial margin of the second article of the antennal peduncle, and a small dorsodistal spine on the merus of the third maxilliped. Raymunida insulata is known only from the holotype from off the Seychelles Islands and its coloration is unknown ( Macpherson & Machordom 2001).

Figures

FIGURE 1. Entire animal, dorsal view, showing coloration in preservative. A, Galathea ternatensis De Man, 1902, ovigerous female (cl 6.0 mm), FHU; B, Raymunida iranica, n. sp., holotype, female (cl 12.2 mm), FHU.

FIGURE 2. Raymunida iranica n. sp., holotype, female (cl 12.2 mm), FHU. A, carapace and cephalic appendages, dorsal view (stiff simple setae on right side and short plumose setae on transverse ridges omitted); B, carapace, right pterygostomial flap and eye, lateral view; C, thoracic sternum, ventral view (plumose setae on transverse ridges omitted); D, pleon, showing extended pleomeres 2 – 4, dorsal view (stiff simple setae on right side and short plumose setae on transverse ridges omitted); E, pleomeres 5 and 6 and telson, outer view (stiff simple setae on right side and short plumose setae on transverse ridges omitted). Scale bars: 1.0 mm.

FIGURE 3. Raymunida iranica n. sp., holotype, female (cl 12.2 mm), FHU. A, right anterolateral part of carapace, pterygostomial flap, eye, basal article of antennular peduncle, and antennal peduncle, ventral view (setae omitted); B, right third maxilliped, lateral view (setae omitted); C, right first pereopod, dorsal view (setae omitted); D, same, ventral view. Scale bars: 1.0 mm.

FIGURE 4. Raymunida iranica n. sp., holotype, female (cl 12.2 mm), FHU. A, right second pereopod, lateral view (short plumose setae omitted); B, same, distal part of merus, mesial view (setae omitted); C, distal part of propodus of right second pereopod, ventral view; D, dactylus of right second pereopod, lateral view; E, distal part of merus, of left second pereopod, mesial view (setae omitted); F, right third pereopod, lateral view (short plumose setae omitted); G, same, merus, mesial view; H, right fourth pereopod, lateral view (short plumose setae omitted); I, same, merus, mesial view. Scale bars: 1.0 mm.