Cristimenes brucei, Park, Jin-Ho, Grave, Sammy De & Kim, Won, 2019

Park, Jin-Ho, Grave, Sammy De & Kim, Won, 2019, A new species of the genus Cristimenes Ďuris & Horka, 2017 (Decapoda, Caridea, Palaemonidae), ZooKeys 852, pp. 53-71 : 56-64

Cristimenes brucei sp. nov. Figures 1, 2, 3, 4, 5, 6, 7, 8 A–B, 9 A–C, 10 A–C

Periclimenes commensalis l: Bruce 1982a: 236-238, fig. 2.

Material examined.

Holotype. KOREA - Jeju Special Self-Governing Province • 1 ov. ♀ (pocl 3.80 mm); Munseom Island; 33°13'37"N, 126°34'8"E; depth 20 m; 16 Oct. 2015; JH Park leg.; on Anneissia japonica ( Müller, 1841); NIBRIV0000841118; Paratypes. KOREA - Jeju Special Self-Governing Province • 3 ♀♀ (pocl 2.2, 1.86, 1.83 mm); Munseom Island; 33°13'37"N, 126°34'8"E; depth 20 m; 16 Oct. 2015; JH Park leg.; on A. japonica ; MADBK 120532_006 • 1 ov. ♀ (pocl 3.65 mm); same data; 16 Oct. 2015; JH Park leg.; on A. japonica ; OUMNH.ZC.2018-03-022 • 2 ♀♀, 1 ♂ (pocl 3.34, 3.1, 1.6 mm); same data; 17 Oct. 2015; JH Park leg.; on A. japonica ; MADBK 120532_007 • 3 ♀♀, 1 ♂ (pocl 2.85, 2.2, 1.5, 1.98 mm); same data; 08 Jul. 2016; JH Park leg.; on A. japonica ; NIBRIV0000841119 • 1 ♀ (pocl 1.67 mm); same data; 08 Aug.2016; JH Park leg.; on A. japonica ; OUMNH.ZC.2018-03-023 • 1 ♀ (pocl 2.45 mm); same data; 31 Mar. 2018; JH Park leg.; on A. japonica ; MADBK 120532_017.

Additional material.

KOREA - Dadohaesang National Park • 1 ♀ (pocl 2.7 mm); Geomundo Island; 34°3'35"N, 127°16'57"E; depth 20 m; 5 Jul. 2014; JH Park leg.; on A. japonica ; MADBK 120532_002 - Gyeongsangbuk-do • 1 ♀, 3 ♂♂ (pocl 1.95, 2.0, 1.7, 1.6 mm); Pohang-si, Guryongpo; 36°0'25"N, 129°35'10"E; depth 15 m; 22 Sep. 2016; JH Park leg.; on A. japonica ; MADBK 120532_015 - Jeju Special Self-Governing Province • 5 ♀♀, 1 ♂ (pocl 2.5, 2.3, 2.2, 1.7, 1.45, 2.0 mm); Beomseom Island; 33°13'7"N, 126°30'50"E; depth 20 m; 28 Feb. 2015; JH Park leg.; on A. solaster (Clark, 1907); MADBK 120532_003 • 8 ♀♀, 1 ♂ (pocl 2.77, 2.6, 2.6, 2.5, 2.5, 2.4, 2.3, 2.1, 1.9 mm); same data; 16 May 2015; JH Park leg.; on Catoptometra rubroflava (Clark, 1908); MADBK 120532_004 • 1 ov. ♀, 6 ♀♀, 3 ♂♂ (pocl 3.43, 3.48, 3.21, 3.1, 3.08, 2.37, 2.3, 2.89, 2.54, 1.97 mm); same data; 17 May 2015; JH Park leg.; on A. japonica ; MADBK 120532_005 • 1 ♀, 1 ♂ (pocl 1.83, 1.83 mm); Saeseom Island; 33°14'2"N, 126°33'49"E; depth 20 m; 30 Jan. 2016; JH Park leg.; on A. japonica ; MADBK 120532_011 • 3 ♀♀, 2 ♂♂ (pocl 2.45, 2.24, 1.2, 2.0, 1.68 mm); Seopseom Island; 33°13'55"N, 126°35'51"E; depth 15 m; 28 Jan. 2016; JH Park leg.; on A. japonica ; MADBK 120532_010 • 1 ♀, 2 ♂♂ (pocl 3.0, 2.16, 1.89 mm); same data; 28 Apr. 2016; JH Park leg.; on A. japonica ; MADBK 120532_013 • 1 ♂ (pocl 2.27 mm); same data; 28 Apr. 2016; JH Park leg.; on A. japonica ; OUMNH.ZC.2018-03-024 • 1 ♀ (pocl 3.5 mm); same data; 28 Apr. 2016; JH Park leg.; on A. japonica ; OUMNH.ZC.2018-03-025 • 1 ♂ (pocl 1.89 mm); same data; depth 30 m; 16 Jul. 2015; JH Park leg.; on A. solaster ; MADBK 120532_008 • 2 ♀♀, 2 ♂♂ (pocl 2.74, 1.05, 1.53, 1.47 mm); same data; depth 27 m; 31 Jan. 2016; JH Park leg.; on A. japonica ; MADBK 120532_012 • 1 ♂ (pocl 1.9 mm); Jeongbang Waterfall point; 33°14'36"N, 126°34'16"E; depth 15 m; 18 Jul. 2015; JH Park leg.; on A. solaster ; MADBK 120532_009 • 2 ♀♀, 2 ♂♂ (pocl 3.5, 2.76, 2.55, 2.0 mm); Jigwido Island; 33°13'36"N, 126°39'12"E; depth 20 m; 14 Apr. 2013; JH Park leg.; on A. japonica ; MADBK 120532_001 • 1 ♂ (pocl 1.77 mm); Unjin Port point; 33°13'2"N, 126°14'42"E, depth 18 m; 20 Oct. 2016; SH Lee leg.; on A. japonica ; MADBK 120532_016.

Diagnosis.

Rostrum well developed, with dorsal and ventral teeth. Carapace smooth, without epigastric tooth; lateral carinae feebly developed; supraorbital tooth reduced, blunt; inferior orbital angle pointed; antennal and hepatic teeth well developed. Fourth thoracic sternite without median process. Abdomen with rounded pleura. Telson with two pairs of small dorsal spiniform setae, and with three pairs of posterior spiniform setae. Eyes with hemispherical cornea. Basal antennular segment with two acute distolateral teeth. Antennal basicerite with sharp distoventral tooth; scaphocerite with large distolateral tooth, not reaching distal end of lamella. Epistome rounded. Mandible without palp; molar process robust; incisor process with four or five terminal teeth. Maxillula with bilobed palp. Maxilla with blunt palp, basal endite well developed, bilobed. First maxilliped with simple palp; basal and coxal endites fused; exopod with developed caridean lobe; epipod bilobed. Second maxil liped with subquadrate epipod, without podobranch. Third maxilliped with slender exopod; arthrobranch rudimentary. First pereiopods slender, fingers subspatulate with entire cutting edges. Second pereiopods equal in shape and subequal in size; palm articulated subproximally; cutting edges of fingers feebly dentate proximally, serrated distally. Dactyli of ambulatory pereiopods biunguiculate; corpus with two or three acute dorsodistal spinules, with acute preterminal accessory tooth. Uropodal exopod with distolateral tooth and movable acute spine.

Description.

Rostrum (Figs 2A, B, 9A, B) well developed, slightly overreaching distal end of antennular peduncle; upper margin slightly convex with 6-8 dorsal teeth, ventral margin convex with 0-3 ventral teeth.

Carapace (Figs 2A, B, 9A, B) smooth without epigastric tooth; lateral carinae feebly developed; supraorbital tooth reduced, blunt (Fig. 9C); inferior orbital angle pointed; antennal and hepatic teeth (Fig. 2C) well developed, antennal tooth long and slender, hepatic tooth larger than antennal tooth; pterygostomial angle rounded.

Thoracic sternite (Fig. 3D) without special features; fourth thoracic sternite without finger-like median process.

Abdomen (Fig. 1) smooth; pleura of first to fifth segments rounded; sixth segment with pointed posterolateral angle, posteroventral angle blunt (Fig. 2E).

Telson (Fig. 2D, E) 0.78 of pocl, 3.2 times longer than proximal width; two pairs of small dorsal spiniform setae at 0.53 and 0.82 of telson length, with three pairs of posterior spiniform setae, outer pair short, inner pair long and stout.

Eye (Figs 2B, 3A) with hemispherical cornea, dorsolaterally with nebenauge; eyestalk 1.2 times as long as wide.

Antennule (Fig. 3B) well developed; basal segment with two acute distolateral teeth, with submarginal medioventral tooth; stylocerite reaching to middle of proximal segment; intermediate and distal segment subequal in length; upper flagellum biramous, proximal four segments fused, shorter free ramus with five segments, 0.3 of longer free ramus.

Antenna (Fig. 3C) well developed; basicerite with sharp distoventral tooth; ischiocerite and merocerite unarmed; carpocerite reaching to 0.4 of scaphocerite; scaphocerite 2.4 times as long as maximal wide, distolateral tooth large, not reaching distal end of lamellae.

Mandible (Fig. 4A) without palp; molar process robust, with four strong teeth and brush-like setae; incisor process with four or five terminal teeth.

Maxillula (Fig. 4B) with bilobed palp; upper lacinia broad, with stout and simple spines, with plumose setae on lower margin; lower lacinia robust with long spines distally, with plumose setae on lower margin.

Maxilla (Fig. 4C) with blunt palp, with sparsely plumose setae; coxal endite obsolete; basal endite well developed, bilobed, with sparsely plumose setae; scaphognathite 2.9 times as long as wide.

First maxilliped (Fig. 4D) with long simple palp, with sparsely plumose setae along the medial margin of the palp; basal and coxal endites fused, with serrulate setae medially; exopod with developed caridean lobe, flagellum with long simple seta; epipod bilobed.

Second maxilliped (Fig. 4E) with subquadrate epipod, without podobranch; merus and carpus without special features; propodus with slender simple setae; dactylus 2.7 times as long as wide, with dense serrulate setae distally.

Third maxilliped (Fig. 4F) with endopod slightly overreaching distal end of carpocerite; ischiomerus approximately six times longer than wide, medially sparsely setose; penultimate segment 0.56 length of ischiomerus, medially with long serrulate setae; terminal segment tapering, slightly downcurved distally, subequal to penultimate segment, with transverse rows of setae and group of terminal hamate setae; exopod slender with plumose setae distally; coxa with large rounded epipod, arthrobranch rudimentary.

First pereiopod (Fig. 5A, B) overreaching distal end of scaphocerite; ischium 0.56 length of merus, unarmed; merus and carpus subequal in length; carpus 1.36 times length of chela with row of serrulate setae along distomesial margin; chela 1.9 times longer than deep; palm with transverse row of serrulate setae ventrolaterally; fingers subspatulate, 0.89 times length of palm, cutting edge straight, entire, with groups of setae.

Second pereiopods (Figs 6A, B, 10A) equal in shape and subequal in size; ischium 0.7 length of merus, unarmed; merus 2.0 times as long as carpus, unarmed; carpus short, 1.2 times as long as maximal width, articulated subterminally (Fig. 6C); palm cylindrical, 1.1 times as long as finger, articulated subproximally; fingers stout with curved tip; cutting edges of fingers feebly dentate proximally, serrated distally (Figs 6D, E, 10C, D).

Ambulatory pereiopods (Fig. 5C, E, F) of usual shape for genus, third pereiopod overreaching end of scaphocerite by distal margin of carpus. Third pereiopod (Fig. 5C) with ischium 0.54 length of merus, unarmed; merus 0.85 times length of propodus, unarmed; carpus 0.46 times length of propodus, unarmed; propodus with three distolateral spiniform setae including single distoventral one; dactylus 0.18 times length of propodus, biunguiculate; corpus with three acute dorsodistal spinules, with acute preterminal accessory tooth, ventral margin straight, with simple distal setae laterally; unguis 0.58 times as long as corpus (Fig. 5D).

Fourth pereiopod (Fig. 5E) with ischium 0.57 length of merus, unarmed; merus 0.80 times length of propodus, unarmed; carpus 0.42 times length of propodus, unarmed; propodus with four distolateral spiniform setae including two distoventral ones; dactylus 0.18 times length of propodus, biunguiculate; corpus with two acute dorsodistal spinules, with acute preterminal accessory tooth, ventral margin straight, with simple distal setae laterally; unguis 0.64 times as long as corpus.

Fifth pereiopod (Fig. 5F) with ischium 0.54 length of merus, unarmed; merus 0.74 times length of propodus, unarmed; carpus 0.38 times length of propodus, unarmed; propodus with five mesial spiniform setae, distolateral one absent; dactylus 0.18 times length of propodus, biunguiculate; corpus with two acute dorsodistal spinules, with acute preterminal accessory tooth, ventral margin straight, with simple distal setae laterally; unguis 0.70 times as long as corpus.

Pleopods as usual for genus. First pleopod of male (Fig. 7A) with endopod 2.8 times longer than wide. Second pleopod of male (Fig. 7B) with appendix masculina with stout, long setae; appendix interna slightly longer than appendix masculina. Second pleopod of female (Fig. 7C) as usual for genus.

Uropod (Fig. 2E) overreaching distal end of telson; exopod with distolateral tooth and movable acute spine.

Etymology.

The new species is named in honour of Dr AJ (Sandy) Bruce, in recognition of his considerable contribution to the systematics of Palaemonidae .

Colour.

Body colour (Fig. 8A, B) orange or reddish-brown adapted to the colour of the host crinoids; creamy white line extending from the tip of the rostrum to the posterior dorsal margin of the carapace; similar, but thinner and lighter line extending from posterior ventral angle of the sixth abdominal segment to the lateral side of the first antennular peduncle.

Ecology.

The specimens were collected from the crinoids Anneissia japonica , A. solaster and Catoptometra rubroflava at a depth of 15 - 27 m. Bruce (1982a) reported that the Hong Kong specimens were collected from Tropiometra afra (Hartlaub, 1890).

Distribution.

Presently only known from the type locality, Jeju Special Self-Governing Province, Korea as well as Hong Kong ( Bruce 1982a).

Remarks.

The new species is morphologically very similar to the other crinoid-associated species in the genus, C. commensalis (Fig. 8C). Within the genus, both species share the following characteristics: subspatulate fingers of the first pereiopods; proximally dentate and distally serrate cutting edges of the fingers of the second pereiopods (Fig. 10C, D); and the presence of accessory spinules on the anterior margin of the dactyli of the ambulatory pereiopods. The new species can, however, be easily distinguished from C. commensalis by the reduced, blunt supraorbital tooth (Fig. 9 A–C) and reduced rostral carinae (vs. well-developed supraorbital tooth (Fig. 9D) and rostral carinae in C. commensalis ).

Cristimenes brucei sp. nov. can easily be distinguished from the echinoid-associated species C. cristimanus (Fig. 8D) and C. zanzibaricus by the reduced supraorbital tooth and rostral carinae (vs. extremely developed supraorbital tooth and rostral carinae), the presence of accessory spinules on the anterior margin of the ambulatory dactylus (vs. absent), and a different host affiliation, with the latter two species being associated with echinoids.

The crinoid-associated genera Araiopontonia Fujino & Miyake, 1970, Laomenes Clark, 1919, and Unguicaris Marin & Chan, 2006 are phylogenetically closely related to Cristimenes . The new species shares a morphological trait with Araiopontonia odontorhyncha Fujino & Miyake, 1970 in having accessory spinules on the anterior margin of the ambulatory dactylus, but the new species can easily be distinguished from A. odontorhyncha by the reduced supraorbital teeth and rostral carinae, the presence of a hepatic tooth on the carapace, and the low and rounded epistome (vs. developed supraorbital tooth and rostral carinae, absence of hepatic tooth, and well developed rounded epistomial horns in A. odontorhyncha ). All species in the genus Laomenes can be distinguished from the new species by having more strongly developed supraorbital teeth and rostral carinae, well developed sharp epistomial horns and simple biunguiculat ambulatory dactylus. The new species is morphologically similar to U. novaecaledoniae (Bruce, 1968) among species of the genus Unguicaris . The new species shares with U. novaecaledoniae similar first chelipeds, proximally dentate but distally serrate cutting edges of the fingers of the second pereiopods, and the presence of well-developed accessory spinules on the anterior margin of the ambulatory dactyli. The new species can, however, be distinguished from U. novaecaledonia by the presence of reduced supraorbital teeth (vs. absent).