Two new species of the “ Heterocarpus gibbosus Bate, 1888 ” species group (Crustacea: Decapoda: Pandalidae) from the western Pacific and north-western Australia * Author Yang, Chien-Hui Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan Author Chan, Tin-Yam Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan tychan@ntou.edu.tw Author Chu, Ka Hou Department of Biology, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong SAR, China text Zootaxa 2010 2010-02-26 2372 1 206 220 https://www.biotaxa.org/Zootaxa/article/view/zootaxa.2372.1.19 journal article 10.11646/zootaxa.2372.1.19 1175-5326 5307586 Heterocarpus abulbus sp. nov. ( Figs. 1 , 3A–B , 4A–D , 5A ) Heterocarpus gibbosus . — Miyake 1998: 65 (part), pl. 22-3. — Chan & Yu 1987: 54 (part), pl. 1A, B. [ nec Bate 1888 ]. Material examined. Holotype : Taiwan , Dasi fishing port, Yilan County , commercial trawler, 04.IX.2006 , ov. female 36.5 mm cl ( NTOU M00789 ) . Paratypes : Taiwan , Dasi fishing port, Yilan County , commercial trawler , 16. VI .1982 , 1 ov. female 29.4 mm cl, 1 female 22.8 mm cl ( NTOU M00807 ); 02.II.1983 , 2 males 29.5–30.7 mm cl, 2 ov. females 27.0– 27.9 mm cl, 1 female 28 mm cl ( MNHN ) ; 30. VI .1984 , 1 female 28.5 mm cl ( NTOU M00809 ); 14.VII.1984 , 1 male 24.4 mm cl, 1 female 13.4 mm cl ( NTOU M00810 ) ; 14.X.1984 , 1 male 24.2 mm cl, 1 ov. female 25.9 mm cl ( NTOU M00811 ) ; 10.VIII.1988 , 1 female 35.6 mm cl ( NTOU M00812 ) ; 06.IX.1999 , 1 male 26.2 mm cl, 1 ov. female 22.9 mm cl, 1 female 22.6 mm cl ( NTOU M00791 ) ; 30. III .2000 , 2 males 18.3–29.9 mm cl, 2 females 22.5–27.9 mm cl ( RMNH D53127); 10. IV .2000 , 1 male 26.1 mm cl, 1 ovig. female 30.8 mm cl, 3 females 23.0– 23.1 mm cl ( NTOU M00013 ); 31.VIII.2006 , 1 male 19.2 mm cl, 1 ovig. female 25.6 mm cl ( OUMNH . ZC .2009-16-001) ; 04.IX.2006 , 3 males 27.9–32.8 mm cl, 5 ovig. females 29.5–37.3 mm cl, 1 female 27.1 mm cl ( NTOU M00813 ) ; 05.IX.2006 , 6 males 22.7–31.4 mm cl, 2 females 21.0– 25.23 mm cl ( NTOU M00790 ) ; 24. V .2007 , 3 males 16.9–21.4 mm cl, 1 female 19.7 mm cl ( NTOU M00814 ); 01. VI .2007 , 1 male 15.8 mm cl ( NTOU M00815 ); 16.VII.2007 , 1 ov. female 34.7 mm cl ( NTOU M00851 ) ; XI.2007 , 1 male 27.2 mm cl ( NTOUM00816 ) ; 19.XII.2007 , 2 females 27.1–32.7 mm cl ( NTOU M00817 ) . — Donggang fishing port, Pingtung County , commercial trawler , 31.X.1984 , 2 males 21.8–23.8 mm cl ( NTOU M00818 ) ; 23. III .1985 , 2 males 14.4–24.8 mm cl, 3 females 17.5–25.5 mm cl ( NTOU M00819 ); 17.XI.1999 , 8 males 21.8–29.1 mm cl, 9 females 22.2–28.9 mm cl ( NTOU M00820 ) ; 09.XI.2001 , 1 male 24.3 mm cl, 1 ov. female 26.0 mm cl ( NTOU M00014 ) ; 28.VII.2009 , 5 males 22.0– 27.4 mm cl, 1 ov. female 26.3 mm cl, 3 females 21.6–27.5 mm cl (RUMF-ZC-917). Non-type material examined. Philippines , E. Luzon , “ AURORA 2007”, stn CP 2672, 14°57’N , 121°41’E , 276–346 m , 22. V .2007, 4 males 17.8–28.4 mm cl, 4 females 16.5–25.9 mm cl ( NTOU M00792 ) . Description. Rostrum far overreaching scaphocerite, 0.8–1.0 times as long as carapace, gently (males) or strongly (females and juveniles) curving upwards, distally straight and directed anterodorsally; dorsally armed with 6–10 teeth including 3–5 teeth on the rostrum proper and 4 or 5 teeth on the carapace posterior to orbital margin; ventrally armed with 10–14 teeth almost along entire length, tooth size progressively diminishing anteriorly, distal 2 or 3 teeth very small and obscure ( Fig. 1A ). Postrostral carina slightly elevated, basal rostral crest low, maximum height 0.85–1.61 (mean 1.17) times as long as basal rostral height. Carapace with two lateral carinae; postorbital carina rounded, extending posteriorly almost to posterior margin of carapace, curved dorsally at about mid-length; branchiostegal carina sharp on anterior part, becoming broadly rounded posteriorly, extending posteriorly to 75–95% (mean 86%) of lower carapace length. Branchiostegal spine not overreaching antennal spine ( Figs. 1A , 3A ). Abdomen unarmed posteriomedially on all somites, and without sharp dorsal carina or tooth on any somite ( Fig. 1A ). Third somite bluntly carinate dorsally, dorsal boss absent or poorly developed, with lateral longitudinal grooves faint to completely absent ( Figs. 4A–B ). Pleura IV and V each bearing acute posteroventral tooth. Somite VI 1.45–1.67 times as long as maximum height. Telson 1.52–1.72 longer than somite VI, bearing 4 pairs of dorsolateral spines and 3 pairs of terminal spines. Uropods distinctly overreaching telson, exopod bearing fixed disterolateral tooth and strong movable spine. Eye subpyriform and without ocellus. Antennular peduncle with stylocerite sharply acute, nearly reaching distal end of second segment; outer flagellum very long. Scaphocerite 0.46–0.53 times as long as carapace, 2.27–2.63 times as long as wide, blade slightly overreaching distolateral spine, lateral margin feebly convex; flagellum more than 3 times carapace length. Maxilliped III stouter than pereiopods and overreaching scaphocerite, exopod 0.34–0.53 times as long as antepenultimate segment; mastigobranch present ( Fig. 1H ). Pereiopods with mastigobranchs on anterior 4 pairs. Pereiopod I slightly overreaching scaphocerite; chela small but distinct, 0.54–0.60 times as long as carpus. Pereiopods II markedly unequal, shorter one (usually right side) with carpus subdivided into 7–9 articles, proximal article longest, distal article second longest, others articles similar, short; carpus 1.27–1.44 times as long as chela, merus 0.66–0.75 as long as carpus, ischium compressed and produced ventrally ( Fig. 1B ); longer one (usually left side) with carpus subdivided into 21–25 articles and merus subdivided into 8–9 articles ( Fig. 1C ). Pereiopod III overreaching scaphocerite by about dactylus, dactylus 0.29–0.36 times as long as propodus, propodus scattered with long setae ( Fig. 1D ), ventral margin with 6–9 spinules; carpus 0.71–0.85 times as long as propodus, with 1–3 strong spines; merus armed with 3–7 mesial and 7–15 lateral spines along flexor margin ( Fig. 1E ). Pereiopods IV and V similar to III, IV overreaching scaphocerite by about dactylus, carpus armed with 1 (rarely 2) spine(s), merus with 7 or 8 ventral spines ( Fig. 1F ); V overreaching scaphocerite by dactylus and half propodus, carpus with 0–2 (usually 1) spine(s), merus with 6– 8 ventral spines ( Fig. 1G ). Coloration. Body generally orange-pink to orange and with ventral sides dark pink ( Fig. 5A ). Eyes dark brown. Antennular and antennal flagella orangish-pink. Pereiopods dark pink at proximal half and pale pink at distal half, posterior 3 pereiopods also with dactyli and most parts of meri reddish. Eggs dark green. Distribution. Only known with certainty from Taiwan and NE Philippines , probably also from Japan (see Remarks). The Taiwanese material, collected by local commercial trawlers, is assumed to be from about 200–400 m deep. The Philippines specimens were obtained from 276–346 m deep. The Japanese specimen in Miyake (1998) was collected from 500 m deep. Etymology. The specific name refers to the lacking (“ a ”) of an abdominal boss (“ bulbus ”) in the new species. FIGURE 1. Heterocarpus abulbus sp. nov. , holotype, ov. female 36.5 mm cl (NTOU M00789 ): A, entire animal, lateral view; B, right second pereiopod, chela, carpus, merus and distal part of ischium; C, left second pereiopod, chela, carpus, merus and distal part of ischium; D, left third pereiopod, dactylus, propodus and distal part of carpus; E, right third pereiopod, basis, ischium, merus and proximal part of carpus; F, right fourth pereiopod, basis, ischium, merus and proximal part of carpus; G, left third pereiopod, basis, ischium, merus and proximal part of carpus; H, right third maxilliped, basis, ischium and proximal part of merus. Scales = 10 mm. Remarks. Other than having a low basal rostral crest ( Figs. 3A–B ), the present new species is unique in the genus by lacking a distinct abdominal boss. The lateral carinae on the carapace and abdominal boss had been considered as generic level characters of Heterocarpus (see Chace 1989 ). Chan & Crosnier (1997) discussed in details these two characters and treated the species of the “ Heterocarpus / Plesionika laevis ” group belonging to Plesionika Bate, 1888 . With the removal of the “ Heterocarpus / Plesionika laevis ” group, H. abulbus becomes the only species of the genus lacking a distinct abdominal boss. Furthermore, the dorsal profile of the abdominal somite III is rather rounded in the Taiwanese material ( Figs. 4A–B ). In those specimens from NE Philippines , abdominal somite III is dorsally more angulate ( Figs. 4C–D ) but still distinctly blunter than in H. gibbosus ( Figs. 4E–F ), which always has a distinct abdominal boss (see also Crosnier 1988 : pl. IVc–d). Heterocarpus abulbus appeared to be restricted to the northern part of the western Pacific. Other than the present material from Taiwan and NE Philippines , the photograph of “ H. gibbosus ” from Japan in Miyake (1998 : pl. 22-3) shows a very low basal rostral crest and probably is H. abulbus . “ Heterocarpus gibbosus ” is rather rare in Japan and Miyake’s (1998) specimen is now lost (K. I. Hayashi, pres. comm.). There is no “ H. gibbosus ” material in the collection of the National Science Museum, Tokyo and the Natural History Museum and Institute, Chiba (M. Mitsuhashi and T. Komai, pres. comm.). Only a few specimens identified as “ H. gibbosus ” from Japan and the East China Sea are located in the National Fisheries University, Shimonoseki and they all have very high basal rostral crest. Three live specimens of “ H. gibbosus ” collected from Okinawa on display in the Okinawa Churaumi Aquarium also have very high basal rostral crest (TYC pers. observation). Both these are not considered H. abulbus , but rather H. corona . The figure of “ H. gibbosus ” given by Tung et al. (1988: 39 , fig. 40) on an East China Sea specimen actually depicts H. longirostris MacGilchrist, 1905 . The somewhat low basal rostral crest specimens of H. gibbosus reported from SW Luzon, Philippines ( Crosnier 1988 : fig. 6b) and the Gulf of Aden ( Fransen 2006 : fig. 2) have a distinct abdominal boss ( Crosnier 1988 : pl. IVc–d; Fransen 2006 : fig. 8), and therefore, are not H. abulbus . Chace (1985 : fig. 17a) and Kensley (1979 : fig. 4) reported on two “ALBATROSS” specimens from west of Halmahera, Indonesia with low basal rostral crests. Re-examination of these specimens will be needed to see if they represent the true H. gibbosus , H. abulbus or further species.