Alcyonohippolyte maculata, Marin, Ivan, Okuno, Junji & Chan, Tin-Yam, 2011

Marin, Ivan, Okuno, Junji & Chan, Tin-Yam, 2011, On the “ Hippolyte commensalis Kemp, 1925 ” species complex (Decapoda, Caridea, Hippolytidae), with the designation of a new genus and description of two new species from the Indo-West Pacific, Zootaxa 2768, pp. 32-54 : 46-51

Alcyonohippolyte maculata sp. nov.

( Figs. 12–13 , 14 D–F, 15B–H, 16C)

? Hippolyte commensalis Kemp, 1925: 331 (part) [not Kemp, 1925].

Hippolyte commensalis .— Hayashi, 1986: 20 (part) [not Kemp, 1925].

Hippolyte sp.— Minemizu, 2000: 102, unnumbered fig. — Kawamoto & Okuno, 2003: 58, unnumbered fig.

Material examined. Taiwan: holotype, ovigerous female (pcl. 2.5 mm, tl. 12 mm) ( NTOU M00916 ), 1 male (pcl. 1.2 mm, tl. 6 mm) paratype ( NTOU M00917 ), Keelung, Badouzih, 5–6 m, on whitish brown soft alcyoniid coral, coll. I. Marin & R. Y. Lee, 0 7 Jul. 2010; 1 male (pcl. 1.5 mm), 2 ovigerous females (pcl. 1.8 and 2.0 mm), paratypes ( NTOU M00918 , M00920 ), same locality and host as for holotype, coll. I. Marin & R. Y. Lee, 0 3 Jul. 2010; 1 male (pcl. 1.5 mm, tl. 7 mm), 1 ovigerous female (pcl. 2.5 mm, tl. 9.5 mm), paratypes ( NTOU M00919 ), northeastern coast, 8– 10 m., from unidentified soft alcyoniid coral, coll. I. Marin & R. Y. Lee, 30 Jun. 2010. Japan, Ryukyu Islands: 2 males (pcl. 1.6 and 1.8 mm), 2 ovigerous female (pcl. 2.2 and 3.0 mm) ( CMNH –ZC 02395), Iriomatejima, 20 m, coll. R. Minemizu, 23 May 1998; 1 ovigerous female (pcl. 1.8 mm) ( CMNH –ZC 02391), Kume-jima, Tonbara, 30 m, coll. T. Kawamoto, 27 Dec. 2001; 1 ovigerous female (pcl. 2.0 mm, tl. 12 mm) ( CMNH –ZC 02392), Kume-jima, Umagai, 8 m, coll. T. Kawamoto, 0 3 Jun. 2002; 2 males (pcl. 1.2 and 0.8 mm), 1 ovigerous female (pcl. 2.0 mm), ( CMNH –ZC 02390), Okinawa-jima, Maeda-misaki, 4.6 m, from Nephthea sp., coll. T. Yanagisawa, 0 6 May 2006. Australia: 3 females (pcl. 2.0– 2.2 mm) (QM W33479), Great Barrier Reef, Lizard Island. Coconut Beach, patch reef, LI10-005, 14° 41.052 S 145° 28.197 E, snorkeling, 0.5–1.5 m, on Cladiella sp., coll. I. Marin, 25 Aug. 2010.

Description. Female (CMNH–ZC 02391). Carapace ( Fig. 13 B, C) smooth, dorsal surface non-gibbous, covered with several tufts of plumose setae; supraorbital, antennal and hepatic teeth present, antennal tooth acute, situated slightly below orbital angle, hepatic tooth acute, larger than antennal tooth, slightly exceeding distal margin of carapace, situated below and slightly behind level of antennal tooth. Rostrum long, compressed, dorsally unarmed, with single subdistal ventral tooth, proximal lateral rostral lamina with sharp supraorbital tooth situated above level of proximal orbital margin. Orbit well developed, inferior orbital angle slightly produced distally. Pterygostomial angle bluntly projected.

Abdominal somites smooth and unarmed, dorsal part of abdominal somites I–II with numerous tufts of plumose setae; pleura of abdominal somites I–V rounded ( Fig. 12 ). Telson ( Fig. 13 F) slender, about 3.5 times as long as proximal width, narrowing posteriorly, with 2 pairs of small submarginal dorsal spines at 0.5 and 0.75 of telson length; distal margin of telson armed with 4 pairs of spines including pair of short stout lateral spines.

Eyes normal, well developed, with subcylindrical eyestalk and subovate cornea. Eyestalk about 1.5 times as long as wide. Cornea suboval, without papilla.

Antennule ( Fig. 13 D) well developed; basal segment about 1.5 times as long as wide, without ventromedial tooth, but with acute distolateral tooth which overreaching midlength of intermediate segment, inner distolateral angle covered with several long plumose setae; stylocerite well developed, acute, reaching distal margin of basal segment; intermediate segment stout, about twice wider than long, with slightly convex inner lateral margin bearing long plumose setae; distal segment stout, about as long as wide, with long plumose setae along inner lateral margin; proximal part of upper antennular flagellum with 5 segments, shorter ramus with 1 stout segment.

Antenna normal, well developed, basicerite armed with sharp triangular tooth distoventrally, slightly overreaching distal margin of segment; carpocerite stout, about as long as wide, reaching midlength of scaphocerite; flagellum well developed; scaphocerite ( Fig. 13 E) wide, about 1.5 times as long as maximal width, greatly overreaching antennular peduncle, with well developed acute distolateral tooth.

Mouthparts characteristic for the genus and as in other species described above.

Pereiopod I ( Fig. 13 G) robust, unarmed; coxa with arthrobranch; basis with small lobe distoventrally; ischium stout, about as long as wide, with long simple setae along ventral margin; merus stout, about twice longer than wide; carpus stout, shorter than merus and equal to length of propodus, about as long as wide, flaring distally, distal margin overlapping carpo-propodal articulation, with row of stout plumose setae along disto-ventral margin; palm about as long as wide, subcylindrical, smooth; fingers stout, slightly longer than palm, subspatulate, about as long as wide, cutting edges armed with several large acute teeth.

Pereiopod II relatively slender, segments unarmed ( Fig. 13 H); coxa with arthrobranch; basis with small lobe distoventrally, about as long as wide; ischium about as long as wide, smooth; merus about 3 times as long as wide, with straight margins; carpus subdivided into 3 subsegments with ratio of about 2:1:2; palm subcylindrical, length equal to distal carpal segment, about 1.5 times longer than wide, with straight smooth margins; fingers robust, equal to palm length, about 2.5 times as long as wide, subspatulate, cutting edges armed with several large acute teeth.

Pereiopod III–V ( Fig. 13 I, K) similar, relatively slender, with segments unarmed. Pereiopod III–IV with basis about as long as wide; ischium about 3 times longer than wide; merus about 3.5 times as long as wide, with straight margins, bearing large movable spine at distoventral angle; carpus about 3 times as long as maximal width, flaring distally, with distodorsal margin overhanging proximal part of propodus; propodus about 6 times as long as wide, with straight and smooth margins, ventral margin unarmed, bearing small spines at distoventral angle ( Figs. 13 J); dactylus slender, basal part about 1.5 times as long as maximal width, swollen, with elongated and curved main unguis, with small accessory tooth. Pereiopod V similar to other ambulatory pereiopods, except for propodus and dactylus unarmed and without any accessory tooth.

Pleopods normal. Uropods slender, slightly exceeding telson; distolateral margin of exopod without fixed tooth, with long mobile spine only.

Male paratype (NTOU M00919 ). Generally similar to female; male about half size of female ( Fig. 12 ). Both carapace and abdominal somites covered with long plumose setae; rostrum unarmed, styliform, pointed distally ( Fig. 13 C). Propodus of pereiopod III with 3 pairs of spines along distoventral margin, most proximal pair about twice larger than others ( Fig. 13 K, L).

Coloration. General body coloration similar to the coloration of host soft coral: body pale white, covered with dark green rounded patches dorsally and laterally, these patches reticulated with dense fine white spots; patches at posterior part of abdominal somite VI, telson and uropods forming transverse broad bands; anterior part of scaphocerite dark green; cornea reddish, eyestalk greenish with fine white transverse lines; pereiopods whitish transparent, covered with dark green bands ( Figs. 15 B–H, 16C).

Remarks. The present new species can be readily separated from A. dossena sp. nov. by having a normal, nongibbous carapace. On the other hand, A. maculata sp. nov. is rather similar to A. commensalis comb. nov. but differs by bearing tufts of plumose setae on the dorsal surface of the body, particularly on the carapace (vs. carapace and abdomen naked in A. commensalis comb. nov.), the presence of a well developed spine at the distoventral angle of the propodi of pereiopods III and IV in females, and the dactyli of the ambulatory pereiopods (in both sexes) each sometimes bearing an additional small accessory tooth. These differences were mentioned by Hayashi (1986) for specimens collected from alcyonarian hosts, and therefore, they are likely representing A. maculata sp. nov. instead of A. commensalis comb. nov. The “spotted” color pattern of this new species ( Figs. 15 B–H, 16C) is also highly diagnostic and readily separated from the “banded” coloration of A. commensalis comb. nov. ( Figs. 11 , 15 A, 16B).

Some specimens reported by Kemp (1925: C913/1, C914/1) from Port Blair, Andaman Islands as “ Hippolyte commensalis ” may refer to the present new species. These individuals were collected from alcyonarian hosts (“ greyand white Alcyonarian ”, Kemp, 1925) instead of “ Actinian ” which is the host for the type of Alcyonohippolyte commensalis comb. nov. Re-examination of these specimens will be necessary to determine their exact identities.

Host. The specimens from Taiwan were collected from unidentified soft alcyonariid coral (Octocorallia, Alcyonacea , Alcyonariidae) resembling both Sinularia polydactyla (Ehrenberg) and Cladiella digitulata (Klunzinger) (Alcyoniidae) usually co-inhabited by the portuniid crab Caphyra yookadai Sakai, 1933 and symbiotic ctenophores. Specimens from Australia were collected from Cladiella sp. ( Alcyoniidae ).

Etymology. The species is named after its distinctive “spotted” color pattern; “ maculata ” (Latin) for spotted. The standard Japanese name for this species is Uzura-kakure-moebi.

Size. The largest female (ovigerous) has pcl. 3.0 mm, tl. 13.5 mm and the largest male has pcl. 2.2 mm, tl. 11 mm.

Distribution. The present new species is known from Taiwan (the type locality, present study), Japan, Gilbert & Solomon Islands ( Hayashi 1986), the Great Barrier Reef of Australia (present study), and likely also the Andaman Sea ( Kemp, 1925, see Remarks under A. commensalis comb. nov.).

Figures

FIGURE 11. Live coloration of Alcyonohippolyte commensalis (Kemp, 1925) comb. nov. (QM W 33477): A – B, ovigerous female (pcl. 3.0 mm); C, ovigerous female (pcl. 2.5 mm); D, ovigerous female (pcl. 2.7 mm); E, ovigerous female (pcl. 2.3 mm); F, male (pcl. 1.8 mm); G, male (pcl. 2.0 mm).

FIGURE 12. Alcyonohippolyte maculata sp. nov., paratypes (NTOU M 00919), ovigerous female (above) and male (below).

FIGURE 13. Alcyonohippolyte maculata sp. nov., paratypes (NTOU M 00919), ovigerous female (A, B, D – J), male (C, K, L): A – C, carapace; D, antennule; E, scaphocerite of antenna; F, telson; G, pereiopod I; H, pereiopod II; I, K, pereiopod III; J, L, same, distal propodus and dactylus.

FIGURE 14. Variations of female rostrum armature. A – C, Alcyonohippolyte commensalis (Kemp, 1925) comb. nov.: A, ovigerous female (pcl. 2.3 mm) (CMNH – ZC 02394); B, ovigerous female, pcl. 2.2 mm (RUMF); C, ovigerous female (pcl. 2.8 mm) (CMNH – ZC 02394). D – F, Alcyonohippolyte maculata sp. nov.: D, ovigerous female (pcl. 2.2 mm) (CMNH – ZC 02395); E; ovigerous female paratype (pcl. 1.8 mm) (NTOU M 00918); F, ovigerous female (pcl. 2.0 mm) (CMNH – ZC 02390).

FIGURE 15. Live coloration. A, Alcyonohippolyte commensalis comb. nov., ovigerous female (pcl. 1.6 mm) (CMNH-ZC 02393). B – H, Alcyonohippolyte maculata sp. nov.: B – C, ovigerous female paratype (pcl. 2.5 mm) (NTOU M 00919); D – E, holotype ovigerous female (pcl. 2.5 mm) (NTOU M 00916); F, ovigerous female (pcl. 1.8 mm) (CMNH – ZC 02391); G – H, male paratype (pcl. 1.2 mm) (NTOU M 00917).