Redescription of Paraclimenes gorgonicola (Bruce, 1969) (Crustacea: Decapoda Palaemonidae) and establishing P. franklini (Bruce, 1990) as its junior synonym Author Park, Jin-Ho College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea. Author Fransen, Charles H. J. M. 0000-0002-7760-2603 Taxonomy & Systematics Group, Naturalis Biodiversity Center, P. O. Box 9517, NL- 2300 RA, Leiden, The Netherlands. charles. fransen @ naturalis. nl; https: // orcid. org / 0000 - 0002 - 7760 - 2603 charles.fransen@naturalis.nl text Zootaxa 2021 2021-03-02 4938 4 443 456 journal article 7748 10.11646/zootaxa.4938.4.4 d6e0819a-dbc2-4e5c-92b2-0827ef2e7cca 1175-5326 4574922 6DEF7CA7-EB3D-45EF-A8BA-6C2613886E14 Paraclimenes gorgonicola ( Bruce, 1969 ) ( Figs. 1–10 ) Periclimenes gorgonicola Bruce, 1969: 257 [ type locality: South China Sea]; Bruce 1979: 223 ; Müller 1993: 89; Li, 2000: 184. Periclimenes franklini Bruce, 1990a: 55 , figs. 1–5 [ type locality: Coral Sea, off Cairns, Queensland ]; Bruce 1990b: 12 ; 1991: 314, fig. 9; Müller 1993: 87; Li 2000: 182 , fig. 230. Paraclimenes franklini — Bruce 1995: 99 , fig. 45; Li 2004: 820 , figs. 1, 2; De Grave & Fransen 2011: 356 . Paraclimenes gorgonicola — Bruce 1995: 100 ; Bruce 2003: 223 ; De Grave & Fransen 2011: 357 . Paraclimenes cf. franklini — Li et al. 2004: 534 , fig. 20. Paraclimenes franklinae — Li & Bruce 2006: 668 . Paraclimenes sp. — Park et al. 2020 : fig. 15, Table 1. Type material. Holotype : 1 ovigerous female, pocl 4.1 mm , South China Sea , R . V . Cape St. Mary, Cr. 1/64, Stn. 49, T/142 , 21°47.7’N 116°28.5’E to 21°43.3’N 116°28.0’E, depth 60–72 fathoms ( 109–132 m ), with Melithaea ? albitincta ( Ridley, 1884 ), by granton trawl, leg. AJ Bruce, Jan. 10, 1964 , RMNH . CRUS .D.45625 . Paratype : 1 ovigerous female, pocl 4.2 mm , same data as holotype, RMNH . CRUS .D.51596. Additional material examined. 1 male , pocl 2.1mm , Seopseom Islet , Jejudo Island , Korea , 33° 13.785’N 126° 35.770’E , depth 27 m , on Myriopathes lata ( Silberfeld, 1909 ) , by SCUBA , leg. JH Park , Jan. 31, 2016 , SNU-KR_ JH357 ( GenBank number: MT311872 , MT311980 ) ; 1 male 4 females , pocl 2.0– 2.4 mm , same data, Aug. 8, 2016 , NIBRIV0000877261-NIBRIV0000877265 ; 1 female , pocl 2.2 mm , same data, RMNH . CRUS .D.57995; 1 male , pocl 2.0 mm, same data, OUMNH . ZC .2018-03-026; 1 female , pocl 2.7 mm , same data, SNU-KR-JH466 ( GenBank number: MT311873 , MT311981 ) . Description of type material. Carapace smooth ( Figs. 1A , 2 A–C), with some erect setae on surface, with robust hepatic tooth reaching anterior margin of carapace by apex, supraorbital and antennal teeth absent. Rostrum ( Fig. 2 A–C) overreaching antennular peduncle, about as long as scaphocerite, slightly up-curved distally, with 10 dorsal teeth at subequal distances, 2 articulated teeth on postorbital carina at somewhat more distance from each other than from anterior teeth, distalmost 2 teeth small, subdistal; ventral laminal with 4 equidistant teeth, all anterior of eye; lateral carina distinct; row of long plumose setae between teeth on dorsal and ventral margins. Inferior orbital angle subacutely produced. Pterygostomial angle obtusely angulate. Abdomen ( Fig. 1 ) with pleura of first four somites rounded; pleura of fifth somite obtusely angulate; sixth abdominal somite with posterolateral angles acutely produced, posteroventral angle sharply produced. Telson ( Fig. 1 ) about 1.6 times as long as sixth abdominal somite, about 4.0 times as long as anterior width, tapering distally, with 2 pairs of dorsal spiniform setae present at 0.5 and 0.7 of telson length; posterior margin of telson with short lateral pair, long and stout intermediate pair, about 1.5 times length of median pair. Telson ( Fig. 2D ) of paratype with 3 dorsal spiniform setae on left side and 2 on right side; posterior margin of telson with short lateral pair, long and stout intermediate pair, submedian region with 4 pairs of spiniform setae. Eye ( Figs. 1A , 2 A–C) with hemispherical cornea; eyestalk about 1.5 times length of cornea, with distinct posterodorsal nebenauge. FIGURE 1. Paraclimenes gorgonicola ( Bruce, 1969 ) , ovigerous female holotype, pocl. 4.1mm, RMNH.CRUS.D.45625, habitus, lateral. Scale bar = 4mm. Antennula ( Fig. 2 A–C) with peduncle falling short of rostrum and scaphocerite; basal segment of peduncle with distinct sharp distolateral tooth, anterior margin roundly produced; ventromedial tooth distinct, at about 0.45 of length of basal segment, with plumose setae on lateral and dorsodistal surface; stylocerite distally acute, about 0.7 of length of basal segment; intermediate segment of peduncle short, about as long as width; distal segment of peduncle about 1.4 times as long as intermediate segment. Upper flagellum biramous, with proximal 4 segments fused, short free ramus with about 8 segments, fused part and short ramus with long aesthetascs, longer free ramus filiform. Lower flagellum slender, filiform. Antennal basicerite ( Fig. 2 A–C) with sharp lateral tooth. Carpocerite short, reaching to about proximal 0.4 of scaphocerite. Scaphocerite with lamella overreaching antennular peduncle; lateral border almost straight, ending in strong distolateral tooth. Anterior margin of lamella feebly angulated distomedially, overreaching distolateral tooth. Epistome unarmed, normal. Fourth thoracic sternite with round median boss, without finger-like process; fourth and fifth thoracic sternites with posterior oblique lateral ridges separated by median notch; posterior sternites unarmed, narrow. Mouthparts not dissected. Third maxilliped ( Figs. 1 , 3A ) overreaching distal margin of antennal carpocerite by ultimate segment, without arthrobranch; coxa slightly produced medially with 2 long simple setae, rounded lateral plate with short simple setae; basis short, about 0.2 of ischiomeral length, with long simple setae medially; ischiomeral segment with two distinct small spiniform setae distolaterally, about 4.3 times as long as distal width, covered by setae of various length; penultimate segment about 0.75 times length of ischiomeral segment, about 6.8 times as long as distal width, with long and robust serrulate and simple setae medially and laterally; ultimate segment almost half length of penultimate segment, with rows of long and robust serrulate and simple setae; exopod reaching to about 0.75 of ischiomeral segment, with long plumose setae distally. First pereiopod ( Figs. 1 , 3B ) overreaching distal margin of scaphocerite by fingers; coxa with distoventral setose process; basis with setose distoventral process, ventrolateral margin with long simple setae; ischium about 0.6 times merus length, ventrolateral margin with long simple setae; merus about 1.2 times carpus length, about 6.8 times as long as distal width; carpus about as long as chela length, slightly tapering proximally, unarmed; carpopropodal joint with cleaning apparatus medially; chela ( Fig. 3C ) with subcylindrical palm, about 2.6 times as long as proximal depth, fingers about 0.7 of palm length, with several groups of terminal setae, cutting edges entire, tips hooked. FIGURE 2 . Paraclimenes gorgonicola ( Bruce, 1969 ) . A, holotype, ovigerous female, pocl. 4.1mm, RMNH.CRUS.D.45625; B–E, paratype, ovigerous female, pocl. 4.2mm, RMNH.CRUS.D.51596. A, B, anterior appendages, lateral; C, idem, dorsal; D, telson, distal part; E, uropods. Scale bar: A–C, E = 2mm; E = 1mm. Second pereiopods ( Figs. 1 , 4 ) similar in shape, unequal in size; major chela about 1.5 times as long as minor chela length. Major second pereiopod ( Figs. 1 , 4A ) overreaching antennular peduncle by chela and carpus; coxa and basis short, with long simple setae; ischium straight, about 0.9 of merus length, about 5.8 times as long as distal depth, unarmed; merus straight, about 2 times as long as carpus, about 6 times as long as distal width, with few tubercles in distal half; carpus short, about 0.3 of palm length, tapering proximally, with few tubercles; chela about 1.4 times as long as pocl, about 4.6 times carpus length, fingers with subterminal groups of setae; palm about 2.9 times fingers length, subcylindrical, with numerous tubercles and short simple setae on entire surface; fingers ( Fig. 4B ) with two triangular teeth at about 0.3 and 0.45 on both proximal cutting edges, distal cutting edges entire, tips hooked. Minor second pereiopod ( Figs. 1 , 4C ) overreaching antennular peduncle by chela; coxa and basis short, with few long simple setae; ischium straight, as long as merus length, about 6 times as long as distal depth, unarmed; merus straight, about 1.75 times as long as carpus length, about 6 times as long as distal depth, with few tubercles in distal half; carpus short, about 0.5 of palm length, tapering proximally, with few tubercles; chela about 0.9 of pocl, fingers with subterminal groups of setae; palm about 1.6 times fingers length, subcylindrical, with numerous tubercles on entire surface; fingers ( Fig. 4D ) with two shallow teeth at about 0.25 and 0.35 of fingers length on both cutting edges, distal cutting edges entire, tips hooked. Third and fourth pereiopods ( Figs. 1 , 5A, B ) subequal in shape and size; third pereiopod just overreaching distal margin of scaphocerite with dactylus and distal part of propodus; coxa and basis short, with few long simple setae; ischium, merus and carpus about 0.45, 0.85 and 0.5 of propodus length; propodus about 12 times longer than distal depth, about 7.5 times length of dactylus, with four serrated spiniform setae along ventral margin, and two pairs of serrated spiniform setae in ventrodistal part; dactylus ( Fig. 6A ) about 2.6 times longer than proximal width, flexor margin of corpus sinuous, corpus tapering distally, ending distoventrally in large acute accessory tooth, with sensory setae distomedially and distolaterally; unguis demarcated, simple, about 0.55 of corpus length, 1.5 times length of accessory tooth; ischium, merus, carpus and propodus with row of setae, propodus with plumose setae distodorsally. Fifth pereiopod ( Figs. 1 , 5C ) as third and fourth; propodus ( Figs. 5C , 6C ) slightly slenderer than in propodi of third and fourth pereiopods, about 13 times longer than distal depth, with row of single serrated spiniform setae on ventral margin, and pair of serrate spiniform setae in distoventral part, with oblique rows of serrate cleaning setae and single serrate spiniform seta in distoventral part. Uropods ( Fig. 2E ) with protopodite unarmed laterally; exopod with lateral margin almost straight, ending in small, acute distolateral tooth with single mobile spiniform setae; both endopod and exopod about as long as telson. FIGURE 3. Paraclimenes gorgonicola ( Bruce, 1969 ) , paratype, ovigerous female, pocl. 4.2mm, RMNH.CRUS.D.51596. A, left third maxilliped; B, left first pereiopod; C, idem chela, mesial view. Scale bars: A, B = 1mm; C = 0.5 mm. Comparison with type material. The Korean material ( Figs. 7–10 ) generally corresponds to the type material. However, some dissimilarities were noted. The specimens (pocl 2.0–2.7) are somewhat smaller than the two ovigerous females of the type series (pocl 4.1 and 4.2 mm ). The specimens from Korea ( Fig. 8A, B ) harbour 7 or 8 teeth on the dorsal margin of the rostrum whereas 10 teeth are present on the holotype ; the ventral margin of the rostrum has 2 or 3 teeth (whereas 4 in the type material) on the relatively deep ventral lamina which is more shallow in the type material. The carapace and anterior cephalic appendages are almost as described for the holotype , on the carapace of the Korean specimens however no sparsely scattered setae were observed ( Fig. 8A, B ) and the upper antennular flagellum has the proximal 3 segments fused ( Fig. 8F ), whereas in the type material the proximal 4 segments are fused. The abdomen and telson are as described for the holotype ( Figs. 7 , 8 C–D). The third maxilliped has two distinct small spiniform setae on the distolateral margin of the ischiomerus as described for the holotype ( Fig. 8H ). First and second pereiopods are as described for the holotype ( Fig. 9A, B ). The major second pereiopod ( Fig. 9C ) has tubercles on the palm and carpus but not on the distal part of the merus, whereas few tubercles are present in the distal part of the merus in the holotype . The minor second pereiopod ( Fig. 9E ) has the carpus and merus devoid of tubercles, whereas few tubercles are present on the carpus and distal part of the merus in the holotype . The proximal cutting edges of the fingers have two distinct teeth ( Fig. 9 C–F) as in the holotype . The general shape of the ambulatory pereiopods is as described for the holotype , third and fourth pereiopods are similar in shape and length and the fifth pereiopod is slightly longer and more slender than the third and fourth ( Fig. 10A, C, E ). However, the third and fourth propodi of the Korea specimens are slightly more robust than those of the type material (about 8.5 times longer than distal width) and the row of single spiniform setae on the ventral border are simple, entire, not serrate ( Fig. 10B, D, F ). The female second pleopod of the Korean specimens have the endopod with an appendix interna, reaching to about 0.7 of the endopod ( Fig. 8I ). Distribution. West Pacific: currently known from the South China Sea ( type locality), Australia ( Queensland , Coral Sea), New Caledonia ( Tonga ; Vanuatu ) and Korea ( Jejudo Island). Host and habitat. Bruce (1969 , 1979 ) reported that the type specimen and additional specimen were collected with the octocorals, Melithaea ? albitincta ( Ridley, 1884 ) and M. gracillima ( Ridley, 1884 ) . Those specimens previously identified as P. franklini were reported without host information. These specimens were collected with trawls or an Ockelman sledge between 86 to 520 m depth. All Korean specimens reported herein were collected from the antipatharian, Myriopathes lata in 27 m depth by SCUBA diving. The host antipatharian occurs between 20 to 35 m on the rocky reef slope of the western side of Seopseom Islet, Jejudo Island, Korea . FIGURE 4. Paraclimenes gorgonicola ( Bruce, 1969 ) . A, B, paratype, ovigerous female, pocl. 4.2mm, RMNH.CRUS.D.51596; C, D, holotype, ovigerous female, pocl. 4.1mm, RMNH.CRUS.D.45625. A, major second right pereiopod; B, idem, chela, mesial view; C, minor second left pereiopod; D, idem, chela, mesial view. Scale bar: A, C = 2mm; B, D = 1mm. FIGURE 5. Paraclimenes gorgonicola ( Bruce, 1969 ) , paratype, ovigerous female, pocl. 4.2mm, RMNH.CRUS.D.51596. A, left third pereiopod, lateral; B, left fourth pereiopod, lateral; C, left fifth pereiopod, lateral. Scale bar = 1mm. FIGURE 6. Paraclimenes gorgonicola ( Bruce, 1969 ) , paratype, ovigerous female, pocl. 4.2mm, RMNH.CRUS.D.51596. A, left third pereiopod, distal part propodus and dactylus; B, left fourth pereiopod, distal part propodus and dactylus; C, left fifth pereiopod, distal part propodus and dactylus. Scale bar = 0.25 mm. Coloration. Unknown. Remarks. The type material examined herein generally corresponds to the brief original description of Paraclimenes gorgonicola provided by Bruce (1969) . However, some characters which were not stated in the original article are disclosed here, especially the carapace with the sparsely scattered setae ( Fig. 2 A–C), the rostrum with plumose setae on both dorsal and ventral carinae ( Fig. 2 A–C), the third maxilliped with two small but distinct distolateral spiniform setae on the ischiomerus ( Fig. 3A ), the second pereiopods with scattered low tubercles from the chela to merus ( Fig. 4 ), the minor second chela with two subacute low teeth on the proximal cutting edge ( Fig. 4D ), as well as the ambulatory propodi with distally serrate ventral and distoventral spiniform setae ( Fig. 6 ). With these newly revealed characters, holotype and paratype do possess the two articulated postrostral teeth ( Fig. 2 A–C) which were not noted in the type description. The ovigerous female paratype has a sort of atavistic aberration on the distal margin of the telson with a row of setae between the long intermediate spiniform setae ( Fig. 2D ). Paraclimenes franklini has been distinguished from P. gorgonicola by the two articulated postrostral teeth (vs. non-articulated in the original description of P. gorgonicola ) and the longer stylocerite, reaching to about 0.8 of the first antennular peduncle (vs. reaching to about 0.5 in the original description of P. gorgonicola ) ( Bruce 1969 , 1990a ). However, further records of P. franklini show a variable length of the stylocerite (reaching to about 0.7 of the first antennular peduncle basal segment) ( Bruce 1991 ; Li et al. 2004 ). The type material of P. gorgonicola examined herein clearly shows the distinct articulated postrostral teeth and the stylocerite reaching to about 0.7 of the basal segment of the antennular peduncle in the holotype and about 0.8 in the paratype specimen ( Fig. 2 A–C). Therefore, these characters cannot be used to differentiate the two species. Furthermore, P. gorgonicola and P. franklini share additional characters in the presence of two small spiniform setae on the distolateral margin of the ischiomerus of the third maxilliped and in the scattered low tubercles on the second chelae. Although morphological differences in the presence or absence of sparsely scattered setae on the carapace can be seen between specimens of P. gorgonicola and P. franklini , it seems to be mere individual variation and not of any taxonomic significance. Paraclimenes franklini ( Bruce, 1990a ) is therefore herein regarded as a junior synonym of P. gorgonicola ( Bruce, 1969 ) . FIGURE 7. Paraclimenes gorgonicola ( Bruce, 1969 ) from Jejudo Island, Korea, habitus non-ovigerous female, pocl 2.4 mm, NIBRIV0000877263. Scale bar = 3mm. FIGURE 8 . Paraclimenes gorgonicola ( Bruce, 1969 ) from Jejudo Island, Korea, non-ovigerous female, pocl 2.4 mm, NIBRIV0000877263. A, anterior appendages, lateral; B, idem, dorsal; C, telson, dorsal; D, idem, distal part; E, uropods; F, antennule, dorsal; G, antenna, ventral; H, third maxilliped; I, second pleopod, mesial. Scale bar: A–C, E–G, I = 1.0mm; D, H = 0.5mm. FIGURE 9 . Paraclimenes gorgonicola ( Bruce, 1969 ) from Jejudo Island, Korea, non-ovigerous female, pocl 2.4 mm, NIBRIV0000877263. A, right first pereiopod; B, idem, chela, mesial view; C, major second left pereiopod; D, idem, distal part of chela, mesial view; E, minor right pereiopod; F, idem, chela, mesial view. Scale bar: A, C, E = 1.0mm; B, D, F = 0.5mm. FIGURE 10. Paraclimenes gorgonicola ( Bruce, 1969 ) from Jejudo Island, Korea, non-ovigerous female, pocl 2.4 mm, NIBRIV0000877263.A, right third pereiopod, lateral; B, idem, distal part propodus and dactylus; C, right fourth pereiopod, lateral; D, idem, distal part propodus and dactylus; E, right fifth pereiopod, lateral; F, idem, distal part propodus and dactylus. Scale bar: A, C, E = 1.0mm; B, D, F = 0.3mm. Bruce (1969 , 1979 ) reported P. gorgonicola to be associated with the gorgonarian Melithaea spp. from the north South China Sea. Since then, the species has been reported without host information from near the type locality (north South China Sea) ( Li et al . 2004 ), New Caledonia ( Bruce 1991 ) and Queensland ( Bruce 1990a ). The present material represents not only the first record of P. gorgonicola from Korea , considerably extending its known northern distribution in the West Pacific, but also adds a new host record with the antipatharian Myriopathes lata . Moreover, our specimens were collected from 27 m depth, which is much shallower than previous records ( 86 – 520 m ). The genus Paraclimenes has been regarded belonging to the group of deep-sea palaemonid genera. Within this group, the absence of an antennal tooth has been considered diagnostic for the genera Paraclimenes and Mesopontonia . They also share the presence of articulated postorbital teeth and the absence of a supraorbital tooth, but they can be easily distinguished by the presence ( Paraclimenes ) or absence ( Mesopontonia ) of an exopod on the third maxilliped. In addition, Mesopontonia has been reported in association with octocorals simarly as Paraclimenes , e.g. M. gorgoniophila Bruce, 1967 ; and M. verrucimanus Bruce, 1996 ( Park et al. 2020 ). A molecular phylogenetic analysis has also revealed that Paraclimenes and Mesopontonia are more closely related to each other than to other deep-sea palaemonid genera ( Park et al. 2020 ). The Atlantic genus Urocaris also shares characters with Paraclimenes like the absence of an antennal tooth, and the presence of an exopod on the third maxilliped. Urocaris however, does not appear to be closely related to Paraclimenes as it has an acute median process on the epistome (one of the main diagnostic generic characters; see Bruce 2007 ). Moreover, Urocaris has been recorded free living on algal beds and has not been recorded in association with gorgonarians (see De Grave et al. 2006 , as Periclimenes longicaudatus ( Stimpson, 1860 ) .