Coralliocaris nudirostris ( Heller, 1861 )

Mitsuhashi, Masako & Takeda, Masatsune, 2008, Identity of the coral-associated pontoniine shrimp species, Coralliocaris nudirostris (Heller, 1861) and C. venusta Kemp, 1922 (Crustacea: Decapoda: Palaemonidae), with descriptions of two new species, Zootaxa 1703, pp. 1-24 : 2-11

Coralliocaris nudirostris ( Heller, 1861)

(figs 1A, B, & 2–5; 6A, B)

O [edipus] nudirostris Heller, 1861: 27 .

Oedipus nudirostris: Heller, 1862: 279 , pl. 3 (fig 25).

Coralliocaris nudirostris: Borradaile, 1898: 385 (list);?1917: 324, 382 (key), 384 (list) [=? C. brevirostris , see ‘Remarks’]. — Holthuis, 1952: 12 (list). —? Holthuis, 1953: 59. —? Bruce, 1972: 406;? 1974b: 260 (fig unnumbered, bottom, colour illust), 262;? 1977a: 12;? 1977b: 70 (text), 73 (fig unnumbered, upper left, colour illust). — Marin et al., 2004: 201 (fig 2a-n).

Coralliocaris venusta Kemp, 1922: 269 (key), 274, figs 100, 101. —? Ramadan, 1936: 1 (text), 23. —? Armstrong, 1941: 13. —? Holthuis, 1952: 191, fig 93. —? Patton, 1966: 277 –278, 288 (tab 1). —? Bruce 1972: 405 –406, 414 (key); 1974b: 261 (fig unnumbered, bottom, colour illust), 262;? 1976b: 138; 1977a: 67, fig 12 j–m;? 1977b: 70 (text), 73 (fig unnumbered, centre, colour illust);? 1977c: 13; 1978b: 131;? 1979: 240;? 1981: 4 (text), 26 (tab 1). — Li, 1997; 244 (tab).

Coralliocaris venusta: Bruce, 1976a: 35 (text).

Coralliocaris venusta: Bruce, 1980: 339 (tab), 342 (text); 1983: 201 (text).

Coralliocaris venusta a: Bruce, 1998: 32 (text), 37 (key). — Mitsuhashi, 2000; 5, 6 (fig 8, colour illust).

Coralliocaris tahitoei Boone, 1935: 180 , pl. 49, fig 12 (part, see ‘Remarks’).

Not Coralliocaris nudirostris: Bruce, 1972 : fig 2b, 414 (key) [= C. brevirostris Borradaile, 1898 see ‘Remarks’]. — Kamezaki et al., 1988; 158 (colour illust) [= C. sandyi new species]. — Mitsuhashi, 2000; 3 (fig 3, colour illust), 4.

Not Coralliocaris venusta: Bruce, 1976a: 32 –35, fig 12 [= C. sandyi new species].

Not Coralliocaris venusta: Bruce, 1978a: 282 , fig 42 [in part = C. sandyi new species].

Material examined. Red Sea: coll. Frauenfeld, 1Ψ(CL 4.11 mm), NHMW Nr. 7790, lectotype (designated in this study, see ‘Remarks’).

Japan: Kaminato, Hachijo-jima Island, Izu Islands, from Acropora sp., Sept. 6, 1994, coll. J. Okuno and S. Kato, 1ov.Ψ(CL 2.91 mm), NCMNH-ZC 00078; Bora fishing port, Miyako-jima Island, Ryukyu Islands, 2m depth, from Acropora tenuis (Dana) , Nov. 23, 1997, coll. M. Mitsuhashi, 1ov.Ψ(CL 2.43 mm), NSMT-Cr 1917; off Nakamoto beach, Kuroshima Island, Ryukyu Islands, 2m depth, from Acropora sp., Jun. 13, 1999, coll. M. Mitsuhashi, 1ov.Ψ(CL 3.24 mm), 1ɗ(CL 2.38 mm), NSMT-Cr 1931. Taiwan: Banana Bay, Kenting, Ping-Tung County, from Acropora sp., Nov. 20, 1982, coll. Y. S. Chen, 1ɗ(CL 3.41 mm), NTM-Cr. 0 0 0 365. China: Dadonghai Bay, Sanya, Hainan Islands, from living coral, Mar. 1, 1997, coll. X. Li, 1ɗ(CL 2.35 mm), IOCAS-CJ97C-120B. Paracel Islands: Macclesfield Bank, stn 31, 16°04.5’S, 114°42.2’E, Jun. 14, 1964, 1ov.Ψ(CL 2.10 mm), 1Ψ(CL 1.39 mm), QM-W28263. India: N.E. Tholayram Paar, Gulf of Manaar, Feb., 1914, coll. J. Hornell; 1ov.Ψ(CL 3.00 mm), 1ɗ(CL 1.63 mm), ZSI c 429/1 (Syntypes of Coralliocaris venusta Kemp, 1922 ). Society Islands: Venus Point Reef, Tahiti, Aug. 15, 1931, coll. the cruise of the Yacht ‘Alva’, 1Ψ(CL 2.78 mm), VMM 786 (holotype of C. tahitoei Boone, 1935 ). Loyalty Islands: Lifou, Santal Bay, 4m, 20°52.4’S, 167°08.5’E, Nov. 26-27, 2000, 1Ψ(CL 1.90 mm), MNHN-Na 15443. Australia: NW reef slope, from Acropora sp., May 29, 1979, coll. L. Owens, 1Ψ(CL 1.95 mm), QM Ref. 2919 3/3.

Description of lectotype. Large mature female (CL 3.05 mm). Body (fig 2A) strongly depressed dorsoventrally; integument smooth. Carapace (fig 2A, B) with strong antennal spine; anterolateral margin rounded. Rostrum (fig 2A–C) directed downward, slightly overreaching distal margin of basal segment of antennular peduncle; upper margin without perceptible tooth, but marked with a feeble depression at subdistal part and a short seta; lower margin unarmed; supraorbital eave regularly expanded posteriorly, not angled.

Fourth thoracic sternite without process. Abdomen (fig 2A) forming large marsupium with broadly expanded pleurae on anterior 3 segments; third segment slightly shorter than second segment, slightly produced posterodorsally; pleurae of fourth and fifth segments rounded posteroventrally; sixth segment slightly longer than deep, with acute posterolateral tooth. Telson (fig 2D) slightly shorter than 3 times of greatest width, with 2 pairs of small dorsolateral spines; anterior pair situated at slightly posterior to mid-length of telson, posterior pair situated at slightly anterior to posterior 1/4; posterior margin convex, with 3 pairs of spines, outermost pair shortest; intermediate pair thickest and longest, about 0.1 of telson length, 3 times of outermost spine, innermost pair 0.6 of intermediate spine in length. Eyes (fig 2A, B) with globular cornea; eyestalk elongate, subcylindrical, 1.5 times longer than width. Antennular peduncle (fig 2B, E) reaching 2/3 of scaphocerite; medial margin length of basal segment slightly shorter than greatest width; lateral margin roundly convex, terminating in an acute spine on left, 3 small spinules on right; with a small blunt spine at posterior 2/3 of ventral surface; stylocerite reaching to 3/4 of length of basal segment, slightly shorter than level of intermediate segment base; intermediate segment slightly wider than medial margin length, with a line of several long plumose setae on medial margin; distal segment as long as wide, slightly widened distally; upper flagellum biramous, fused part composed of 8 articles.

Antenna (fig 2B) with carpocerite reaching distal 1/3 of scaphocerite; basicerite with robust distolateral spine; scaphocerite twice as long as broad, with slightly concave lateral margin; distolateral spine of scaphocerite not reaching distal margin of blade. Mouthparts are based on left side, except third maxilliped. Mandible (fig 3A) deeply divided into incisor and molar processes, without palp; incisor process tapering distally, armed with 4 small teeth, inner 2 teeth somewhat smaller than outer teeth. Maxillula (fig 3B) with bilobed palp, upper lobe short, lower lobe with 2 apical setae; basal endite with about 15 finely serrated spines on medial margin; coxal endite slender, with long setae subdistally. Maxilla (fig 3C) with short simple non-setose palp; endite greatly reduced to single lobe, bearing long apical seta, shorter than half length of palp length, scaphognathite well developed, about 1.7 times longer than central width. First maxilliped (fig 3D) bearing short apical seta on palp; basal endite rounded, fringed with setae on medial margin; coxal endite feebly produced medially, bearing few setae on medial margin; exopod about 3 times as long as basal endite, with long plumose setae distally; caridean lobe broad, subrectangular fringed with plumose setae; epipod large, bilobed. Second maxilliped (fig 3E) with dactylar segment with stout curved setae along medial margin; propodus not produced anteriorly, with few setae on anteromedial angle; epipod well developed, subrectangular in shape, longer than broad; podobranch absent. Third maxilliped (fig 3F) with stout endopod; basis incompletely fused with ischiomerus; ischiomerus about half as long as width, with setae along distal part of medial margin, lateral margin with several setae, without spine; penultimate segment about half of length of ischiomeral segment, as long as width, somewhat convex medially, with dense groups of finely serrate short setae on medial margin; terminal segment as long as penultimate segment, width half of the length, medial margin with dense groups of finely serrate short setae, mediodistal part with rather long curved setae, distolateral margin with several short setae; epipod large, rounded; arthrobranch with 10 lamellae on right, 12 on left; exopod reaching distal end of endopod when extended, fringed with plumose setae distal half. First pereiopod (fig 4A, B) slen- der; chela little less than half length of carpus; dactylus about 2/3 of palm length, with several tufts of short setae on medial and lateral surfaces; fixed finger with a few tufts of long setae on dorsomedial surface; medial surfaces of fingers with concavity on medial surface; palm with recurved serrate setae medioventrally; carpus about as long as merus, with a line of long setae at distomedial part; ischium 1/3 of merus length.

Second pereiopods (fig 4C, D) large, robust, subequal; chela large, about twice of carapace length; dactylus half of palm length, slightly bends laterally, ends with stout hooked tip, medioventral surface with welldeveloped flange forming longitudinal ridge; cutting edge with 2 subtriangular teeth on proximal half; fixed finger with 3 subtriangular teeth on cutting edge and slender, hook-shaped tip; 2 small shallow concavities at slightly medial to cutting edge corresponding to 2 teeth of dactylus; palm subcylindrical, somewhat compressed, becoming broader proximally, greatest width 2/5 of length; carpus short, about 1/3 as long as palm; distoventral margin with 5 to 7 obscure dentations; medioventral process blunt; merus compressed, about 0.6 of palm length; distomedial process triangular.

Third to fifth pereiopods (fig 4E, F) similar, robust; each dactylus short, distally blunt, extensor surface with strongly curved hook-shaped protuberance; propodus 4 times as long as dactylus, with 4 transverse rows of short dense setae distoventrally, a few groups of long setae on dorsodistal margin; carpus about half of propodus and merus, slightly longer than ischium, with robust process at dorsodistal margin; dorsal surface with scattered long setae. Pleopods (fig 4G, H) well developed; first pleopod with short setae on basipodite; endopod of first pleopod overreaching half of exopod length; appendix interna of second to fifth at about 1/4 of endopod length. Uropod overreaching tip of telson; exopod 3 times as long as width, with an acute immovable tooth and a movable spine at distal 1/4 of lateral margin.

Notes on other specimens. Medium-sized females (CL 1.39–3.24 mm) and smaller, slender males (CL 1.63–3.41 mm).

Rostrum (fig 5A–C) reaching or overreaching intermediate segment of antennular peduncle; dorsal margin unarmed or armed with 1 or 2 teeth on distal half; ventral margin unarmed or with subdistal 1 tooth (tab 1); supraorbital eave slightly convex, and nearly straight. Antennular peduncle with 1 lateral spine on basal segment; greatest width subequal to medial margin length.

Abdominal segments with broadly rounded pleura; third segment length about 1.5 times of second segment in females, twice as long as in males.

Eyes (fig 5A, B) large; eyestalk slightly longer than width.

Basal segment of antennular peduncle (fig 5A, B) normally with distolateral tooth.

First pereiopod (figs 5D, E; 6A) with concavity on medial surface of fingers as in lectotype. Chela of second pereiopod about twice as long as CL in females, about 2.5 to 3 times in males; fingers elongated in males.

Third to fifth pereiopods (fig 6B) each with 4 rows of relatively curly or straight setae on propodus distoventrally.

Colour in life. Ovigerous females (fig 1A) generally translucent with scattered fine orange dots; large, elongate white patches on branchiostegite and gastric region of carapace, abdominal pleuron and pleopods; distal parts of fingers of second pereiopods white; third to fifth pereiopods with longitudinal white patches on lateral surfaces; proximal and distal parts of uropods white; distal part of uropodal exopod with a translucent patch. [Based on specimens: NSMT-Cr 1917, 1931; NCMNH-ZC 000365.]

Male (fig 1B) similar to female in bearing white patches on carapace, abdomen and uropods, but less marked with white patches.

Remarks. In order to check the true identity of C. nudirostris , we examined the syntypes preserved in the Natural History Museum in Vienna. Seven specimens labelled as the syntypes of C. nudirostris were kept in the museum, but four of them are amphipods (P. C. Dworschak, 1998, personal communication), and two were identified by us as Jocaste japonica ( Ortmann, 1890) and Harpiliopsis beaupresii (Audouin, 1826) respectively. The seventh specimen (a female) corresponds with the description by Heller (1861), clearly based on a female, and also with the additional figures by Heller (1862). Therefore this syntypic specimen is herein designated as lectotype. After the original and additional descriptions of C. nudirostris, Borradaile (1917) proposed a key to the species of the genus Coralliocaris and provided an additional locality for C. nudirostris: Goifurfehndu Atoll , the Maldive Islands, but without further details of the specimen. In his key, C. nudirostris is characterised by the rostrum bearing no teeth and overreaching the first joint of the antennule, and the antennular stalk nearly reaching the end of the antennal scale. We examined the specimen that is kept in the Zoological Museum, Cambridge (1 ovigerous female CL 4.41mm, Ah.1920). The reexamination of the specimen revealed that it actually belongs to C. brevirostris Borradaile, 1898 due to the rounded, convex cutting edge of the distal half of the fixed finger of the second pereiopod. Borradaile (1917) probably misidentified the specimen, as it has a longer rostrum compared to the type specimen of C. brevirostris . The descriptions of C. nudirostris by Heller (1861, 1862) are brief and do not indicate clear differences from C. brevirostris except the longer rostrum. Bruce (1972) checked the same specimen, and figured the anterior part of the carapace as C. nudirostris (p 412, fig 2b). Bruce (1972) also provided a key to the species and separated C. nudirostris by rostral length, and further used the non-carinated dactylus of second pereiopod and the basal segment of antennular peduncle being as long as wide. These characters do not agree with the lectotype of C. nudirostris in that the dactylus of the second pereiopod is carinated, and the basal segment of the antennular peduncle being slightly shorter than wide. The key by Bruce (1998) is based on the same specimen (Bruce, personal communication) and harbours the same deficiency.

Kemp (1922) described C. venusta based on one ovigerous female and one male from the Gulf of Manaar without a comparison with C. nudirostris . The original description and illustrations by Kemp (1922) are much more detailed compared with the original description of C. nudirostris , and clearly shows there is no distinct character separating it from C. nudirostris , except the rostrum being armed with one to two dorsal teeth and one ventral tooth in C. venusta . The armed rostrum has been treated as the major diagnostic character of C. venusta by some authors ( Chace & Bruce 1993; Borradaile 1917; Bruce 1998), whilst others consider it to be individual variation (e.g. Holthuis 1965; Patton 1966; Bruce 1976a). We examined the type specimens of C. venusta and C. nudirostris and numerous new materials from various museums. All materials of C. nudirostris sensu lato are very similar to each other, but the specimens can be separated into two groups on the basis of presence or absence of a concavity on the medial surface of the first pereiopod finger. The type specimens of C. venusta and C. nudirostris , and specimens of the ‘white patched morph’ of C. venusta exhibit a concavity. The rostral dentition of these specimens is variable (see Table 1 ) with rostral teeth sometimes being small and indistinct. Indeed, the lectotype specimen of C. nudirostris shows only a slight elevation on the dorsal margin of the rostrum (fig 2C) counted here as 0/0. Based on these facts, it is thus concluded that C. nudirostris s.s., C. venusta s.s. and the ‘white patched morph’ of C. venusta are referred to a single species, with C. venusta as a junior synonym of C. nudirostris . The other species (‘black striated morph’ of C. venusta ) which has no concavity on the fingers of the first pereiopod is described below as a new species.

Coralliocaris tahitoei Boone, 1935 was regarded as a junior synonym of C. nudirostris by Holthuis (1952:17), but there are some discrepancies between the original description of C. tahitoei and C. nudirostris , i.e., slender endopod of third maxilliped, distal segment being five times as long as wide, penultimate segment being four times as long as wide, ischiomeral segment being four times as long as wide, and presence of only one tooth on cutting edge of second pereiopod dactylus. In C. nudirostris , the endopod of the third maxilliped is stout and the distal segment is twice as long as width, the penulutimate segment is as long as width, the ischiomeral segment is twice as long as width, and the cutting edge of the second pereiopod dactylus has two teeth. To investigate the true status of C. tahitoei , the holotype deposited at the Vanderbilt Marine Museum (now transferred to the American Museum of Natural History, New York City), CL 2.78 mm, Cat.no.786, was examined. The specimen is badly damaged, and the telson and part of the third to sixth abdominal segments are missing. The appendages are detached except for the mouthparts, left first pereiopod, proximal part of second pereiopods from merus, left fifth pereiopod and pleopods. The detached left second pereiopod and right fourth or fifth pereiopod are also contained in the same bottle. The specimen agrees well with the characters of C. nudirostris and has a concavity on the medial surface of the fingers of the left first pereiopod which is attached to the body. The third maxilliped also shows the typical character of C. nudirostris and is clearly different from the original description by Boone (1935). The detached left second pereiopod in the bottle was identified as that of Harpiliopsis beaupresii . Harpiliopsis beaupresii has a remarkably slender third maxilliped and one tooth on the dactylus of the second pereiopod which agrees with the description by Boone (1935) of C. tahitoei . It is thus concluded that C. tahitoei was described based upon at least two specimens, actually referable to C. nudirostris and H. beaupresii .

The names of the previously reported colour morphs are somewhat complicated. The colour morphs were first reported by Bruce (1976a) and named ‘()’ for the colour morph described as ‘inconspicuously coloured, being a translucent whitish shade with a fine pattern of alternating minute lines of black and white chromatophores over the carapace and abdomen. These lines are generally more or less longitudinal but form whorls over the dorsal aspects, particularly of the carapace.’ This colour morph can be considered as the ‘black striated morph’ in this study. Another colour morph named ‘()’ characterized by large opalescent white patches will be regarded as the ‘white patched morph’. In Bruce (1980; 1983), the ‘white patched morph’ is designated as ‘ ’ and the ‘black striated morph’ as ‘ ’. Bruce (1998) used ‘a type’ for the ‘white patched morph’ and ‘b type’ for the ‘black striated morph’.

The problem is there are many records of C. venusta without colour information on the specimens and very few notes on the absence or presence of a concavity on the fingers of the first pereiopods. That makes it difficult to identify the specimens previously recorded as C. venusta . One of the specimens of C. venusta from northern Australia is accompanied by a note of the colour pattern as ‘uniform light reddish brown with faint spots on the tips of the chelae’, which does not agree with the ‘white patched morph’ nor any other colour pattern in the present study. We located the specimen, but failed to access the specimen with the colouration note. Other specimens reported by Patton (1966) from Heron Island were identified as C. sandyi , a new species, which would have had a black striated colour pattern in life. The specimen of C. venusta recorded by Bruce (1977a) from the Capricorn Group, is noted to possess concavity on the fingers of the first pereiopod as ‘fingers are hollowed ...’ and agrees with the character in C. nudirostris .

The two specimens of C. nudirostirs reported by Bruce (1974b; 1977b) show quite different colour pattern from the white patched pattern of this species. We could not check the specimens directly, but judging from the photographs, they are rather similar to C. brevirostris from the morphology of the dactylus of the second pereiopod. The colour pattern of C. brevirostris is not reported and we can not identify from the colour information. It is possible that they are misidentified from the key by Borradail (1917) and Bruce (1972) as mentioned above.

Distribution. The type locality is the Red Sea. Widely distributed in Indo-West Pacific, from Hachijyojima Island (Izu Islands, southern Japan), Kuro-shima Island and Miyako-jima Island (Ryukyu Islands, southwestern Japan), southern Taiwan, Hainan Island (southern China), Gulf of Manaar ( India, type locality of C. venusta ), Tahiti (type locality of C. tahitoei ), Loyalty Islands and Heron Island (Capricorn Islands, Australia).

Tables

TABLE 1. Individual variation in rostral dentition (upper / lower) in Coralliocaris nudirostris, C. sandyi sp. nov. and C. labirintha sp. nov. (Total number of the specimens examined in brackets).

	0/0	1/0	2/0	3/0	0/1	1/1	2/1	3/1	4/1	1/2	4/2	5/2
Coralliocaris nudirostris (14)	9	0	1	0	1	3	0	0	0	0	0	0
Coralliocaris sandyi sp. nov. (19)	9	4	3	1	2	0	0	0	0	0	0	0
Coralliocaris labyrintha sp. nov. (21)	0	0	2	1	0	2	6	5	3	0	1	1