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Metacyclops brancelji Athibai & Wongkamhaeng & Boonyanusith 2022, sp. nov.
No full textMetacyclops brancelji sp. nov. urn:lsid:zoobank.org:act: C420CB65-D63C-4E04-A734-3F5B62D67043 Figs 10–15; Tables 1–2 Diagnosis FEMALE. Body size moderate (0.89–0.96 mm; n = 6), without integumental pits. Posterior margin of second pedigerous somite undulated, those of third and fifth pedigerous somite with serrated hyaline frill. Genital double-somite dorsally with two sensilla and transverse suture, representing the remnant of ancestral articulation of the siXth thoracic somite and the first abdominal somite. Anal operculum developed, reaching insertion of caudal ramus; free margin smooth and concave. Caudal rami ca 2.6–2.9× as long as wide, ornamented with 3–4 spinules at anterior third length on lateral surface and few spinules at base of seta II, combined with a row of strong spinules latero-ventrally at base of seta III. Seta VI slightly shorter than seta III. Setal and spine formulae of exp-2 of P1–P4 5.5.5.5 and 3.4.4.3, respectively. P4 exp-2 with single apical spine; spine slightly shorter than segment. Inner spine of free segment of P5 longer than segment, ca 1.5× as long as segment; outer seta on P5 ca 2.5× as long as inner spine. MALE. Body length 0.71–0.76 mm (n = 3). Caudal rami ca 2.5–2.8 × as long as wide. P6 with two elements; inner (ventral) spine robust, slightly shorter than outer seta. Etymology The name is a masculine noun in genitive singular, raised after Professor Dr Anton Brancelj (National Institute of Biology, Ljubljana, Slovenia) in honor of his great contribution to the diversity of subterranean Copepoda in Thailand. Type material Holotype THAILAND • ♀ (completely dissected and mounted on a slide in glycerol and sealed with nail polish); Satun Province, Phupha Phet Cave; 7°07′28.94″ N, 99°59′52.14″ E; 92 m a.s.l.; 17 Dec. 2014; C. Boonyanusith leg.; temporary pool; hand net; ZMB 34231 slide No. 5124. Allotype THAILAND • ♂ (completely dissected and mounted on a slide in glycerol and sealed with nail polish); same collection data as for holotype; ZMB 34231 slide No. 5125. * = measured from the illustration of the description § = Malaysian specimens (Lim & Fernando 1985) ? = after Mercado-Salas et al. (2013) † = Chinese specimens (Shen & Tai 1964) Paratypes THAILAND • 1 ♀, 1 ♂ (each completely dissected and mounted on a slide in glycerol and sealed with nail polish); same collection data as for holotype; ZMB 34231 slide No. 5126–5127 • 1 ♀ (stored in a miXture of glycerol and 70% ethanol (ratio ~1: 10 v /v)); same collection data as for holotype; ZMB 34231a. Additional material examined THAILAND – Satun Province • 1 ♀, 1 ♂ (each completely dissected and mounted on one slide in glycerol and sealed with nail polish); Rakhang Thong Cave; 7°05′42.18″ N, 99°55′05.64″ E; 55 m a.s.l.; 31 Jul. 2015; C. Boonyanusith leg; rimstone; hand net; ZMB 34231 slide No. 5128–5129 • 1 ♂ (specimen stored in a miXture of glycerol and 70% ethanol (ratio ~1: 10 v /v)); same collection data as for preceding; ZMB 34231b • 2 ♀♀, 1 ♂ (processed for taking photographs by SEM); same collection data as for the preceding; collection of the third author (CB). – Songkhla Province • 1 ♀ (completely dissected and mounted on a slide in glycerol and sealed with nail polish); Khao Nui Cave; 6°59′32.16″ N, 100°08′28.35″ E; 78 m a.s.l.; 15 Dec. 2014; C. Boonyanusith leg;; pool filled by dripping water; hand net; ZMB 34231 slide No. 5130 • 1 ♀ (specimen stored in a miXture of glycerol and 70% ethanol (ratio ~1: 10 v /v)); same collection data as for preceding; ZMB 34231c Type locality The new species was collected from a pool in Phupha Phet Cave, Manang District, Satun Province, southern Thailand (Fig. 1A, D). The cave is located in a limestone hill of the Nakhon Sri Thammarat Mountain range. Beyond the entrance there is a very large cave tunnel, separated to several rooms and decorated well with stalactites, stalagmites, flowstones and rimstones, with a wooden bridge throughout the cave and installed lights. The collecting point is about 100 meters from the entrance, being a large temporary pool in the room, named “Dok Boa Khwam” (Upside-down lotus flower). Water comes primarily from the epikarst zone of the cave, and the depth varies according to season, ranging from 5 cm in dry season to 40 cm in rainy season. In collecting date, the water was about 40 cm deep, covering an area of about 30 m 2, transparent and colorless. Description Adult female Total body length, measured from tip of rostrum to posterior margin of caudal rami, 0.89–0.96 mm (mean = 0.94 mm; n = 6; holotype = 0.89 mm) (Fig. 10A). Body without integumental pits (Fig. 11A–B). Naupliar eye not discernible. Rostrum V-shaped in frontal view, with rounded tip, completely fused to cephalothoraX, with two sensilla laterally. Prosome ca 65% of body length and ca 1.87 × as long as length of urosome. CephalothoraX anteriorly oval, ca 32% of body length and ca 1.08 × as long as wide, with greatest width at posterior end; posterior margin smooth. Posterior margin of second pedigerous somite undulated; third pedigerous somite with serrated hyaline frill on posterior margin; posterior margin of fourth pedigerous somite smooth (Figs 10A, 11A). Fifth pedigerous somite with two transversal rows of spinules located between proXimal seta and free segment of P5, with two sensilla dorsally; posterior margin with serrated hyaline frill. Genital double-somite symmetrical, ca 0.82× as long as wide, tapering posteriorly, dorsally with two sensilla and transverse suture, representing the remnant of ancestral articulation; posterior margin with serrated hyaline frill (Figs 10A–B, 11B). Seminal receptacle with clear distinction between anterior and posterior lobes; anterior lobe short and wide; posterior lobe globular, narrower than anterior one. Second and third abdominal somites narrower than genital doublesomite, ca 56% of double-somite width, with serrated hyaline frill on posterior margin (Figs 10A, 11B). Anal somite with row of minute spinules latero-ventrally on posterior margin and two sensilla dorsally at base of anal operculum (Fig. 10C). Anal operculum developed, trapezoidal, reaching insertion of caudal ramus; free margin smooth and concave (Fig. 10C). CAUDAL RAMI (Figs 10C–D, 11C). Relative short, ca 2.7 × as long as wide, with siX setae; all setae pinnate. Seta I absent. Seta II inserted at ⅓ of caudal ramus length. Seta III spiniform, inserted at posterior outer corner of ramus. Seta IV and seta V with breaking planes. Seta V, the longest, ca 0.33 × as long as body length. Seta VI slender, slightly shorter than seta III. Seta VII inserted dorso-medially at ⅕ of ramus length. Length ratio of caudal setae to ramus length, from seta II to seta VII: 0.27: 0.84: 3.82: 4.98: 0.70: 0.82. Lateral surface ornamented with 4–5 minute spinules located at anterior ⅓ of ramus length, with few minute spinules at base of seta II and a row of strong spinules latero-ventrally at base of seta III. ANTENNULE (Fig. 12A). Eleven-segmented, reaching ca ⅔ of cephalothoraX; armature formula: 1-[8], 2-[4], 3-[6], 4-[2], 5-[1+I], 6-[2], 7-[3], 8-[2+ae], 9-[2], 10-[2+ae], 11-[8]. Fifth segment with short spine on posterior outer corner. Aesthetasc on eighth and tenth segments slender, inserted near outer seta, as long as seta. Eleventh segment with acrothek sub-apically. ANTENNA (Fig. 12B). Four-segmented, comprising coXobasis and three-segmented enp; setal formula 3.1.9.7. Coxobasis robust, with three transversal rows of spinules on caudal surface and two smooth setae on inner distal corner; seta representing eXp spinulose, inserted on outer distal corner and reaching tip of enp-3. Enp-1 ca 1.5× as long as wide, with smooth seta on medial margin. Enp-2 ca 1.5 × as long as wide, with longitudinal row of minute spinules on outer margin and nine setae; seven setae inserted along medial margin and two setae inserted apically. Enp-3 ca 2.0 × as long as wide, with two longitudinal rows of minute spinules along outer margin and seven smooth setae apically; outermost seta shortest. MANDIBLE (Fig. 12C). Gnathobase with strongly chitinized teeth on cutting edge and spinulose seta dorsally; seta completely fused to segment. Palp reduced, one-segmented, with one short, slender seta and two long, bipinnate setae; two long setae subequal in length, ca 10 × as long as shorter one. MAXILLULE (Fig. 12D). Three-segmented, composed of robust praecoxa and two-segmented maxillulary palp, representing coxobasis and enp.Arthrite of praecoxa with three strong claw-like extensions apically and one spinulose seta sub-apically. PraecoXa with seven elements along medial margin; proXimalmost seta minute, sub-proximal seta robust and spinulose, three middle setae slender and smooth, sub-distal seta robust and smooth, distalmost seta robust and spinulose. Basal segment of palp with three elements apically; outer apical seta robust and armed with long spinules on outer margin; inner apical and subapical ones smooth. Exp reduced, represented by spinulose seta near lateral segment of palp. Enp represented by lateral segment of palp, with two setae apically and one seta sub-apically; all setae spinulose, subequal in length. MAXILLA (Fig. 12E). Five-segmented. Praecoxa and coxa partly fused frontally. Praecoxal endite prominent, inserted medially, with one smooth and one spinulose setae apically. CoXa with two endites; proXimal endite with one smooth seta apically; distal endite rectangular, movable, with two spinulose setae apically; spinules on proXimal seta of distal endite relatively long, those of distal one minute. Basis with claw-like endite and two setae at base of claw; longest seta strong, inserted ventrally to claw; shorter one slender, inserted on caudal surface above the longest seta; concave margin of claw with oblique row of spinules; spinules fused to basis and increased in size from frontal spinule to caudal one. Enp twosegmented; enp-1 with two robust setae; enp-2 with strong seta apically and two smooth, slender setae sub-apically. MAXILLIPED (Fig. 12F). Four-segmented, composed of syncoxa, basis and two-segmented enp. Syncoxa with two endites and ornamented with arch row of spinules on outer margin; proXimal endite with two subequal spinulose setae apically; distal endite with one spinulose seta. Basis with one seta on caudal surface; basal endite with one spinulose seta apically, with a row of long spinules on frontal surface. Enp-1 with strong spinulose seta. Enp-2 with three setae; apical seta strong, two other ones slender and smooth. P1‒P4 (Fig. 13). Two-segmented enp and exp. Intercoxal sclerite of P1 with few spinules on distal prominences, those of P2‒P4 with 3‒6 smaller spinules. CoXa with one seta on distal inner corner. Basis with one seta laterally and hairy medially. Setal and spine formulae of eXp-2 of P1‒P4: 5.5.5.5 and 3.4.4.3, respectively. Armature of swimming leg as in Table 1. P1 (Fig. 13A). Frontal and caudal surfaces of intercoXal sclerite bare; distal prominence with 2‒3 spinules. Lateral seta on basis ca 4 × as long as those of P2‒P4; inner seta pinnate, reaching mid of enp-2. EXp-1 with outer spine and inner seta. EXp-2 as long as wide, with three spines and five setae; apical spine ca 0.71 × as long as segment. Enp-1 with inner seta. Enp-2 ca 1.5× as long as wide, with outer seta inserted between claw-like eXpansion, apically with robust spine and seta, inner margin with three setae; outer seta ca 1.3 × as long as length of apical spine; apical spine strong, slightly curved, as long as segment. P2 (Fig. 13B). IntercoXal sclerite as in P1, with 4‒5 spinules on distal prominence. Basis with two hooklike eXpansions: outer eXpansion located between insertions of eXp and enp; inner one smaller, located at the same place where the medial seta of basis of P1 inserted. Lateral seta on basis ca 0.25 × as long as that of P1. EXp-1 with outer spine and inner seta. EXp-2 ca 1.5× as long as wide, with four spines and five setae; apical spine slightly shorter than segment. Enp-1 with inner seta. Enp-2 ca 1.7× as long as wide, with outer seta inserted between claw-like expansion, apically with robust spine and seta, inner margin with four setae; outer seta ca 1.3× as long as length of apical spine; apical spine strong and straight, as long as segment. P3. Frontal surface of intercoXal sclerite bare; caudal surface with transversal row of minute spinules and distal prominences with 4‒6 minute spinules (Fig. 13C). Basis, eXp, and enp similar to those of P2. P4 (Fig. 13D). IntercoXal sclerite similar to that of P3; yet distal prominences with 3‒4 spinules. Distal margin of coxa with rows of spinules on caudal surface. Basis similar to those of P2 and P3. Exp-1 with outer spine. EXp-2 ca 1.4 × as long as wide, with three spines and five setae; spines relatively smaller than those of P1‒P3, apical spine ca 0.5× as long as segment. Enp-1 with inner seta. Enp-2 ca 1.7 as long as wide, with outer seta inserted between claw-like expansion, apically with robust spine, inner margin with four setae; outer seta ca 1.3 × as long as length of apical spine; apical spine ca 0.9 × as long as segment. P5 (Fig. 13E‒F). One-segmented, inserted on postero-lateral corner of fifth pedigerous somite. ProXimal segment completely fused to somite, represented by lateral seta. Distal segment free, subquadrate, ca 1.1 × as long as wide, with one slender outer seta and one inner spine apically; inner spine ca 1.5× as long as segment and outer seta ca 2.5× as long as inner spine. P6 (Figs 10B, 11B). Small, forming simple cuticular plate inserted latero-dorsally on genital doublesomite, and armed with one seta dorsally and two minute spiniform setae ventrally. Adult male Total body length, eXcluding caudal seta, 0.71–0.76 mm (mean 0.74 mm; n = 3; allotype = 0.71 mm) (Fig. 14A). Habitus smaller and slenderer than in female. Naupliar eye and rostrum as in female. Prosome ca 62% of body length and ca 1.57 × as long as length of urosome. CephalothoraX anteriorly oval, representing ca 32% of body length and ca 1.12 × as long as wide. Second to fifth pedigerous somites similar to those of female. Genital somite swollen on mediolateral margin (Fig. 14A–B); ca 25% length of urosome and ca 0.6× as long as wide, with hyaline frill latero-dorsally. First abdominal somite and two subsequent somites narrower than genital somite, ca 60% of genital somite width, with serrated hyaline frill on posterior margin. Anal somite and operculum similar to those of female. CAUDAL RAMI. As long as that in female, ca 2.7× as long as wide. Armament and ornamentation similar to those of female. Length ratio of caudal setae to ramus length slightly different to that of female; ratio of caudal setae to ramus length from seta II to seta VII: 0.29: 0.82: 3.94: 5.50: 0.70: 0.97. ANTENNULE (Fig. 14C–E). 16-segmented, geniculate. Armature formula as follows: 1-[8+3ae], 2-[4], 3-[2], 4-[2+ae], 5-[1], 6-[2], 7-[2], 8-[2], 9-[1+ae+I], 10-[2], 11-[2], 12-[I], 13-[2+ae], 14-[0], 15-[1], 16-[12]. Eleventh and thirteenth segments with pinnate seta each. ANTENNA, MANDIBLE, MAXILLULE, MAXILLA, MAXILLIPED. Similar to those of female. P1. Frontal and caudal surfaces of intercoXal sclerite bare and distal prominences with 2‒3 minute spinules (Fig. 15A). Coxa, basis, enp and exp similar to those of female. P2. IntercoXal sclerite as in P1, distal prominences with 4‒5 minute spinules (Fig. 15B). CoXa, basis, enp and exp similar to those of female. P3. Frontal surface of intercoxal sclerite bare, caudal one with transversal row of minute spinules and distal prominences with 4‒5 minute spinules (Fig. 15C). CoXa, basis, enp and eXp similar to those of female. P4. Frontal surface of intercoxal sclerite bare, caudal one with transverse row of minute spinules and distal prominences with 3‒4 minute spinules (Fig. 15D). CoXa, basis, enp and eXp similar to that of female; apical spine on enp-2 ca 0.8× as long as segment. P5 (Figs 11D, 14B, 15E‒F). Similar to that of female. Free segment ca 1.1× as long as wide, with one slender outer seta and one inner spine apically; inner spine strong, ca 1.5× as long as segment bearing it; outer seta ca 2.5× as long as inner spine. P6 (Figs 11E, 14B, 15G). Reduced to cuticular plate with two elements; inner spine strong, slightly shorter than outer seta. Variability The female specimens collected in Phupha Phet Cave are slightly smaller (0.89 mm each, n = 2) than those of Rakhang Thong Cave (0.95–0.96 mm, n = 2) and Khao Nui Cave (0.95–0.96 mm, n = 2). Similarly, the male specimens collected in Phupha Phet Cave (0.71 mm, n = 1) are smaller than those of Rakhang Thong Cave (0.75–0.76 mm, n = 2). Unfortunately, because the male has not yet been encountered from Khao Nui Cave, the length of the male is doubtful for this cave. Minor variation in the length/width ratio of the caudal rami, the length of spines of the female P5 and the male P6 are shown in Table 2. Distribution Metacyclops brancelji sp. nov. was encountered in three caves: Phupha Phet Cave and Rakhang Thong Cave (Satun Province; Fig. 1D–G), and Khao Nui Cave (Songkhla Province; Fig. 1D, H). Habitat Metacyclops brancelji sp. nov. was collected during the rainy season from temporary water bodies which are seasonally filled primarily by water from the epikarst zone of the cave. Specimens were collected by hand net from both a large pool (n = 53) and a rimstone (n = 10) (Fig. 1E–F), about 100 meters from the entrance of Phupha Phet Cave. The type locality is in the dark zone where the temperature is relatively constant. Based on four sampling occasions from December 2014 to December 2015, the temperature in the dark zone of Phupha Phet Cave varied from 24.4°C in July 2015 to 27.8°C in April 2015. In Khao Nui Cave, the new species was collected in December 2014 from a water body filled by dripping water (n = 4) at the deepest part of the twilight zone, about 20 meters from the entrance (Fig. 1H). In Rakhang Thong Cave, the new species was collected in July 2015 from a rimstone (n = 33) at the cave entrance. The entrance of Rakhang Thong Cave is located at the base of the hill. The area in front of the entrance is a rock shelter which has been modified for religious propose. Near the rimstone is a Buddha statue and the gutter was created to collect water from the top of the shelter above the rimstone (Fig. 1G). These let us hypothesize that the discovery of M. brancelji sp. nov. in the rimstone of Rakhang Thong Cave is accidental and the new species could be encountered in water bodies around the hill and in the cave, like in Phupha Phet Cave and Khao Nui Cave. Furthermore, if compared to the regional distribution of the three latest described copepod species in Satun Province, including Onychocamptus satunensis Boonyanusith, Saetang, Wongkamhaeng & Maiphae, 2018, Boholina laorsriae Boonyanusith, Wongkamhaeng & Athibai, 2020 and Rangabradya (Siamorangabradya) wongkamhaengae Boonyanusith & Athibai, 2021, the distribution of M. brancelji sp. nov. is wider since it was collected in three separate caves located along the south of the mountain range, while the three above-mentioned species were only encountered in a single cave. The characteristics mentioned above suggest a stygophylic nature of M. brancelji sp. nov. rather than stygophilic, as suggested by many authors that stygophile exhibits an adaptation to spend their whole life and reproduce in subterranean habitats and can live in epigean environments (Galassi 2001; Sket 2008; Brancelj 2015). Differential diagnosis and remarks Currently, four different types of spine formula of enp-2 of P1–P4 have been recognized within the genus Metacyclops (Mercado-Salas et al. 2013). Most of the species (54) and two Thai new species have the type of spine formula of 3.4.4.3. Two species, including M. thailandicus from Thailand and M. cushae Reid, 1991 from Louisiana (USA), bear a spine formula of 3.4.3.3. Metacyclops mortoni Pesce, De Laurentiis & Humphreys, 1996 is the only species that bears a spine formula of 3.4.4.2. The last type of spine formula is 3.3.3.3, represented by two species comprising M. trispinosus Dumont, 1981 from Africa and M. margaretae (Lindberg, 1938) from India (Karanovic 2004a, 2004b; Karanovic et al. 2011). Among the species with a 3.4.4.3 formula, M. sakaeratensis sp. nov. and M. brancelji sp. nov. most closely resemble the Cambodian M. woni Lee & Chang, 2015. Based on characteristics described by Lee & Chang (2015) for M. woni, the two Thai new species and M. woni share the combination of the following characteristics, including: (1) female antennules 11-segmented (2) posterior margin of second pedigerous somite undulated (3) P4 enp-2 with one apical spine (4) seta VI of caudal ramus shorter than seta III (5) caudal rami with spinules at anterior third length of lateral surface (6) male P6 bearing 2 elements However, the two new species can be easily distinguished from M. woni by having: 1) transverse suture representing the remnant of ancestral articulation on the dorsal surface of the genital double-somite (absent in M. woni; Chang pers. com.), 2) serrated hyaline frill on the posterior margin of the third thoracic somite (absent in M. woni), 3) different length/width ratio of the caudal ramus (ca 2.3× in M. sakaeratensis sp. nov. and ca 2.7 × in M. brancelji sp. nov. vs ca 2.5× in M. woni), and 4) a row of spinules on the intercoxal sclerite of P3 (absent in M. woni) (Table 2). The armature of P5 and P6 are additional characters, separating the species (Table 2). In M. sakaeratensis sp. nov. and M. woni, the inner spine of P5 is minute, as long as
Bryocyclops Boonyanusith & Sanoamuang & Brancelj 2018
No full textKey to genera and subgenera of the <i>Bryocyclops</i> group <p>Common characteristics of the group are the following: a) 10- or 11-segmented antennules; b) rami of swimming legs 2-segmented but with additional oligomerization in some species; c) P5 completely fused with Pd5, with baseoendopodal seta laterally (a remnant of the proximal segment of P5 – coxa, basis and Endp), with 2 setae/spines sub-ventrally (a remnant of the Exp P5).</p> <p> 1. Position of P6 vestiges on the posterior half of genital double-somite ……………………………… ……………………………………………………………………… <i>Haplocyclops</i> Kiefer, 1952 (2)</p> <p>– Position of P6 vestiges on the anterior half of genital double-somite ………………………………3</p> <p> 2. P1–P4 Exp-2 spine formula 2.3.3.2 …………………… <b> <i>Haplocyclops</i> (<i>Haplocyclops</i>)</b> Kiefer, 1952</p> <p> – P1–P4 Exp-2 spine formula 2.2.2.2 ………………………………………………………………… …………………………………… <b> <i>Haplocyclops</i> (<i>Kierfercyclops</i>)</b> Karanovic & Ranga Reddy, 2005</p> <p> 3. P5 reduced to one stout spine on Exp lobe; coxa of P4 with one strong, spiniform seta ……………………………………………………………………… <i>Bacillocyclops</i> Lindberg, 1956</p> <p>– P5 with two setae/spines on Exp lobe ……………………………………………………………4</p> <p> 4. P5 remnant of Exp lobe with one spine and one seta; genital double-somite longer than wide; distal segment of P4 Endp with six elements; one spine and one seta apically … <i>Yansacyclops</i> Reid, 1988</p> <p>– P5 remnant of Exp lobe with two setae; genital double-somite as long as wide or wider than long …5</p> <p> 5. P1 without median seta/spine on both coxa and basis; anterolateral seta (II) on caudal ramus positioned dorsally; P1–P4 Endp-2 spine formula 2.2.2.2 ……………… <i>Rybocyclops</i> Dussart, 1982</p> <p>– P1 with one seta/spine on coxa, basis with or without inner seta; anterolateral seta (II) on caudal ramus positioned dorsally or laterally; P1–P4 Endp-2 spine formula not 2.2.2.2 ……………6</p> <p> 6. Male P3 Endp-2 with modified apical spine ………………………………………………………7 ‒ Male P3 Endp-2 without modified apical spine ……………………… <i>Allocyclops</i> Kiefer, 1932 (8)</p> <p> 7. Intercoxal sclerite of P4 with obtuse, slightly rounded prominence; P4 Exp-2 with five setae, P4 Endp distinctly 2-segmented; mandibular palp armed with three setae …………… ……………………………………………………………………………… <i>Siamcyclops</i> gen. nov.</p> <p> – Intercoxal sclerite of P4 with pointed or rounded prominence; P4 Exp-2 with four (only in <i>B. jankowskajae</i> with five) setae, P4 Endp with variable segmentation: 1-segmented, indistinctly 2-segmented or distinctly 2-segmented; mandibular palp armed with one seta or seta absent ……… …………………………………………………………………………… <i>Bryocyclops</i> Kiefer, 1927</p> <p> 8. Coxa of P1–P4 with seta in inner distal corner ……………………………………………………9 – Coxa of P2–P4 without seta in inner distal corner … <b> <i>Allocyclops</i> (<i>Stolonicyclops</i>)</b> Reid & Spooner, 1998</p> <p> 9. Antenna with seta representing Exp; P4 Endp-2 with one apical spine and one outer seta ……… ………………………………………………………… <b> <i>Allocyclops</i> (<i>Psammocyclops</i>)</b> Kieffer, 1955</p> <p> – Antenna without seta representing Exp; P4 Endp-2 with two apical spines ……………………… ……………………………………………………………… <b> <i>Allocyclops</i> (<i>Allocyclops</i>)</b> Kieffer, 1932</p>Published as part of <i>Boonyanusith, Chaichat, Sanoamuang, La-orsri & Brancelj, Anton, 2018, A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups, pp. 1-30 in European Journal of Taxonomy 431</i> on pages 14-16, DOI: 10.5852/ejt.2018.431, <a href="http://zenodo.org/record/1254968">http://zenodo.org/record/1254968</a>
Fig. 3 in A new genus and new species of stygobitic copepod (Crustacea: Copepoda: Cyclopoida) from Thien Duong Cave in Central Vietnam, with a redescription of Bryocyclops anninae (Menzel, 1926)
No full textFig. 3. Pseudograeteriella longiaesthetascus new genus, new species, female. A, P1; B, P2; C, P3; D, P4. Scale bars: 100 μm.Published as part of Sanoamuang, La-orsri, Boonyanusith, Chaichat & Brancelj, Anton, 2019, A new genus and new species of stygobitic copepod (Crustacea: Copepoda: Cyclopoida) from Thien Duong Cave in Central Vietnam, with a redescription of Bryocyclops anninae (Menzel, 1926), pp. 189-205 in Raffles Bulletin of Zoology 67 on page 195, DOI: 10.26107/RBZ-2019-0016, http://zenodo.org/record/457578
Metacyclops sakaeratensis Athibai & Wongkamhaeng & Boonyanusith 2022, sp. nov.
No full textMetacyclops sakaeratensis sp. nov. urn:lsid:zoobank.org:act: 84533C2C-57F3-47AB-8EF3-0DF17C9B4C92 Figs 2–9; Tables 1–2 Diagnosis FEMALE. Body size moderate (0.73–0.75 mm; n = 3), with shallow integumental pits. Posterior margin of second pedigerous somite undulated; those of third and fifth pedigerous somites with serrated hyaline frill. Genital double-somite dorsally with two sensilla and transverse suture, representing the remnant of ancestral articulation of the siXth thoracic somite and the first abdominal somite. Anal operculum developed, reaching insertion of caudal ramus; free margin smooth and straight. Caudal rami ca 2.1–2.3 × as long as wide, with few spinules at anterior third length on lateral surface and at base of seta II, combined with a row of strong spinules latero-ventrally at base of seta III. Seta VI slightly shorter than seta III. Setal and spine formulae of exp-2 of P1–P4 5.5.5.5 and 3.4.4.3, respectively. P4 exp-2 with single apical spine; spine slightly shorter than segment. Inner spine on free segment of P5 as long as segment; outer seta on P5 ca 4.5 × as long as inner spine. MALE. Body slenderer and smaller than female (0.62–0.67 mm; n = 3). Caudal rami ca 2.2–2.4 × as long as wide. P6 with two elements; outer (dorsal) seta about twice as long as inner (ventral) spine. Etymology The species name is a noun. The specific epithet was raised after the ʻSakaeratʼ Subdistrict, where the new species was encountered. Type material Holotype THAILAND • ♀ (completely dissected and mounted on one slide in glycerol and sealed with nail polish); Nakhon Ratchasima Province, Sakaerat Subdistrict; 14°30′21.60″ N, 101°55′08.40″ E; 14 Sep. 2013; C. Boonyanusith leg.; plankton net; ZMB 34230 slide No. 5120. Allotype THAILAND • ♂ (completely dissected and mounted on one slide in glycerol and sealed with nail polish); same collection data as for holotype; ZMB 34230 slide No. 5121. Paratypes THAILAND • 1 ♀, 1 ♂ (each completely dissected and mounted on one slide in glycerol and sealed with nail polish); same collection data as for holotype; ZMB 34230 slide No. 5122–5123 • 1 ♀ adult (stored in a miXture of glycerol and 70% ethanol (ratio ~1: 10 v /v)); same collection data as for holotype; ZMB 34230. Additional material examined THAILAND • 1 ♀, 1 ♂ (stored in a miXture of glycerol and 70% ethanol (ratio ~1: 10 v /v)); same collection data as for holotype; collection of the third author (CB) • 2 ♀♀ (processed for taking photographs by SEM); same collection data as for holotype; collection of the third author (CB). Type locality The new species was collected in a headwater stream in SERS, Sakaerat Subdistrict, Nakhon Ratchasima Province, Northeast Thailand (Fig. 1A–C). The locality is located in a dry evergreen forest and has been known under the name of “Tham Ngu Jong Ang” (King cobra Cave) in Thai language. The name refers to a rock shelter, which is the characteristic of the stream bank in the type locality. The stream reach is about 30 m long and about 4–5 m wide, streambed with bedrock. During dry season, the water does not encompass the channel entirely. The new species was collected in pool-formed area, where the water flows slowly. The mean water temperature was 25.3°C, pH 6.98, conductivity 64.7 µS cm-1, and dissolved oxygen 9.1 mg L- 1. Description Adult female Total body length, measured from tip of rostrum to posterior margin of caudal rami, 0.73–0.75 mm (mean = 0.75 mm; n = 3; holotype = 0.74 mm) (Fig. 2A). Naupliar eye not discernible. Rostrum V-shaped in frontal view, completely fused to cephalothorax, with two sensilla laterally and rounded tip (Fig. 2B). Prosome ca 64% of body length and ca 1.75 × as long as length of urosome. CephalothoraX anteriorly oval, ca 33% of body length and ca 1.15 × as long as wide, with greatest width at posterior margin; posterior margin smooth. Posterior margin of second pedigerous somite undulated, third pedigerous somite with serrated hyaline frill on posterior margin, posterior margin of fourth pedigerous somite smooth (Fig. 2A, C). Fifth pedigerous somite with two transversal rows of spinules located between proximal seta and free segment of P5 (Fig. 3B, D), with two sensilla dorsally; posterior margin with serrated hyaline frill (Fig. 2D). Genital somite and first abdominal somite fused, forming genital double-somite. Genital double-somite symmetrical, ca 0.84 × as long as wide, tapering posteriorly; dorsally with two sensilla and transverse suture, representing the remnant of ancestral articulation (Figs 2D, 4B); posterior margin with serrated hyaline frill (Figs 2D, 3A). Seminal receptacle with clear distinction between anterior and posterior lobes; anterior lobe short and wide; posterior lobe globular, narrower than anterior one (Fig. 3A). Second and third abdominal somites narrower than genital double-somite, ca 56% of double-somite width, with serrated hyaline frill on posterior margin (Fig. 2D). Anal somite with a row of minute spinules latero-ventrally on posterior margin and two sensilla dorsally at base of anal operculum (Fig. 2D). Anal operculum developed, trapezoidal, reaching insertion of caudal ramus; free margin smooth and straight (Fig. 2D). Body with numerous integumental pits; pits shallow, hard to observe and less developed on anal somite (Figs 2C, 4B, E). CAUDAL RAMI (Figs 2D, 3C, 4C). Relatively short, ca 2.25× as long as wide, with siX setae; all setae pinnate. Seta I absent. Seta II inserted at ⅓ of caudal ramus length. Seta III spiniform, inserted at posterior outer corner of ramus. Seta IV and seta V with breaking planes. Seta V, the longest, ca 0.34 × as long as body length. Seta VI slender, slightly shorter than seta III. Seta VII inserted dorso-medially at ⅕ of ramus length. Length ratio of caudal setae to ramus length, from seta II to seta VII: 0.37: 0.91: 4.23: 5.57: 0.86: 1.21. Lateral surface ornamented with few minute spinules located at anterior ⅓ of ramus length, few minute spinules at base of seta II, and a row of strong spinules at base of seta III. ANTENNULE (Fig. 5A). Eleven-segmented, reaching ca ⅔ of cephalothoraX; armature formula: 1-[8], 2-[4], 3-[6], 4-[2], 5-[1+I], 6-[2], 7-[3], 8-[2+ae], 9-[2], 10-[2+ae], 11-[8]. Fifth segment with short spine on posterior outer corner. Aesthetasc on eighth and tenth segments slender, inserted near outer seta, as long as outer seta. Eleventh segment with acrothek sub-apically. ANTENNA (Fig. 5B–C). Four-segmented, comprising coXobasis and three-segmented enp; setal formula 3.1.9.7. CoXobasis robust, with three transversal rows of spinules on caudal surface; two smooth setae on inner distal corner; seta representing eXp spinulose, inserted on outer distal corner and reaching tip of enp-3. Enp-1 ca 1.5× as long as wide, with smooth seta on medial margin. Enp-2 ca 1.5× as long as wide, with longitudinal row of minute spinules on outer margin and nine setae; seven setae inserted along medial margin and two setae inserted apically. Enp-3 ca 2.0 × as long as wide, with two longitudinal rows of minute spinules along outer margin and seven smooth setae apically; outermost seta shortest. LABRUM (Fig. 5D). Trapezoidal in frontal view, with two rows of hairs; cutting edge with 12 teeth medially between two obtuse lateral teeth. MANDIBLE (Fig. 6A‒B). Gnathobase with strongly chitinized teeth on cutting edge and spinulose seta dorsally; seta completely fused to segment. Palp reduced, one-segmented, with one short, slender seta and two long, bipinnate setae; two long setae subequal in length, ca 10 × as long as shorter one. MAXILLULE (Fig. 6C). Three-segmented, composed of robust praecoxa and two-segmented maxillulary palp, representing coxobasis and enp. Arthrite of praecoxa with three strong claw-like extensions apically and one spinulose seta sub-apically. PraecoXa with seven elements along medial margin; proXimalmost seta minute, sub-proximal seta robust and spinulose, three middle setae slender and smooth, sub-distal seta robust and smooth, distalmost seta robust and spinulose. Basal segment of palp with three elements apically; outer apical seta robust and armed with long spinules on outer margin; inner apical and subapical ones smooth. Exp reduced, represented by spinulose seta near lateral segment of palp. Enp represented by lateral segment of palp, with two setae apically and one seta sub-apically; all setae spinulose, subequal in length. MAXILLA (Fig. 6D). Five-segmented. Praecoxa and coxa partly fused frontally. Praecoxal endite prominent, inserted medially, with one smooth and one spinulose seta apically. CoXa with two endites; proXimal endite with one smooth seta apically; distal endite rectangular, movable, with two spinulose setae apically; spinules on proximal seta on distal endite relatively long, those of distal one minute. Basis with claw-like endite and two setae at base of claw; longest seta strong, inserted ventrally to claw; shorter one slender, inserted on caudal surface above the longest seta; concave margin of claw with oblique row of spinules, spinules fused to basis and increased in size from frontal spinule to caudal one. Enp two-segmented; enp-1 with two robust setae; enp-2 with strong seta apically and two smooth, slender setae sub-apically. MAXILLIPED (Fig. 6E). Four-segmented, composed of syncoxa, basis and two-segmented enp. Syncoxa with two endites and ornamented with a row of spinules on outer margin; proXimal endite with two subequal spinulose setae apically; distal endite with one spinulose seta. Basis with one seta on caudal surface; basal endite with one spinulose seta apically. Enp-1 with strong spinulose seta. Enp-2 with three setae; apical seta strong, two other ones slender and smooth. P1‒P4 (Fig. 7). Two-segmented enp and exp. Intercoxal sclerite with minute spinules on distal prominences. Coxa with one seta on distal inner corner. Basis with one seta laterally and hairy medially. Setal and spine formulae of eXp-2 of P1‒P4: 5.5.5.5 and 3.4.4.3, respectively. Armature of swimming leg as in Table 1. P1 (Fig. 7A). Frontal and caudal surfaces of intercoXal sclerite bare, with 2‒3 minute spinules on distal prominences. Lateral seta on basis ca 4× as long as those of P2‒P4; medial seta pinnate, reaching mid of enp-2. EXp-1 with outer spine and inner seta. EXp-2 as long as wide, with three spines and five setae; apical spine ca 0.7 × as long as segment. Enp-1 with inner seta. Enp-2 ca 1.5 × as long as wide, with outer seta inserted between claw-like expansion, apically with robust spine and seta, inner margin with three setae; outer seta ca 1.2× as long as length of apical spine; apical spine strong, slightly curved, as long as segment. P2 (Fig. 7B). IntercoXal sclerite as in P1, yet distal prominences with 3‒4 minute spinules. Basis with two hook-like eXpansions: outer eXpansion located between insertions of eXp and enp; inner one smaller, located at the same place where the medial seta of basis of P1 inserted. Lateral seta on basis ca 0.25 × as long as that of P1. EXp-1 with outer spine and inner seta. EXp-2 ca 1.3× as long as wide, with four spines and five setae; apical spine slightly shorter than segment. Enp-1 with inner seta. Enp-2 ca 1.5× as long as wide, with outer seta inserted between claw-like expansion, apically with robust spine and seta, inner margin with four setae; outer seta inserted between claw-like eXtensions, ca 1.3× as long as length of apical spine; apical spine strong and straight, as long as segment. P3 (Fig. 7C‒D). Frontal surface of intercoXal sclerite bare; caudal surface with transversal row of minute spinules and distal prominences with 3‒4 minute spinules. Basis, eXp, and enp similar to those of P2. P4 (Figs 4D, 7E). Intercoxal sclerite similar to that of P3. Coxa with rows of spinules on caudal surface. Basis similar to those of P2 and P3. EXp-1 with outer spine. EXp-2 ca 2.0 × as long as wide, with three spines and five setae; spines smaller than those of P1‒P3, apical spine ca 0.5× as long as segment. Enp- 1 with inner seta. Enp-2 ca 2.0× as long as wide, with outer seta inserted between claw-like eXpansion, apically with robust spine and seta, inner margin with four setae; outer seta ca 1.3× as long as length of apical spine; apical spine ca 0.8× as long as segment. P5 (Figs 3A‒B, D‒E, 4E). One-segmented, inserted on postero-lateral corner of fifth pedigerous somite. Proximal segment completely fused to somite, represented by lateral seta. Distal segment free, subquadrate, ca 1.1 × as long as wide, apically with one slender outer seta and one inner spine; inner spine as long as segment and outer seta ca 4.5× as long as inner spine. P6 (Figs 3B, 4B). Small, forming simple cuticular plate inserted latero-dorsally on genital double-somite, and armed with one seta dorsally and two minute spiniform setae ventrally. Adult male Total body length, eXcluding caudal seta, 0.62‒0.67 mm (mean = 0.65 mm; n = 3; allotype = 0.65 mm). Habitus smaller and slenderer than in female (Fig. 8A). Naupliar eye and rostrum as in female. Prosome ca 62% of body length and ca 1.62 × as long as length of urosome. CephalothoraX anteriorly oval, representing ca 33% of body length and ca 1.16 × as long as wide. Posterior margins of cephalothoraX and two subsequent pedigerous somites (Fig. 4A) similar to those of female; that of fourth pedigerous somite smooth. Fifth pedigerous somite as that of female. Genital somite swollen on mediolateral margin (Fig. 8A‒B), ca 25% length of urosome and ca 0.62 × as long as wide, with hyaline frill latero-dorsally. First to third abdominal somites narrower than genital somite, representing ca 60% of genital somite width, with serrated hyaline frill on posterior margin. Anal somite and operculum similar to those of female. CAUDAL RAMI. Similar to that of female, ca 2.3 × as long as wide. Armament and ornamentation similar to those of female. Length ratio of caudal setae to ramus length, from seta II to seta VII: 0.42: 0.88: 4.47: 5.83: 0.82: 1.27. ANTENNULE (Fig. 8C). 16-segmented, geniculate. Armature formula as follows: 1-[8+3ae], 2-[4], 3-[2], 4-[2+ae], 5-[1], 6-[2], 7-[2], 8-[2], 9-[1+ae+I], 10-[2], 11-[2], 12-[I], 13-[2+ae], 14-[0], 15-[1], 16-[12]. Eleventh and thirteenth segments with pinnate seta each. ANTENNA, MANDIBLE, MAXILLULE, MAXILLA, AND MAXILLIPED. Similar to those of female. P1. Frontal and caudal surfaces of intercoXal sclerite bare and distal prominences with 2‒3 minute spinules (Fig. 9A). Coxa, basis, enp and exp similar to those of female. P2. IntercoXal sclerite as in P1, yet distal prominences with 3‒5 minute spinules (Fig. 9B). CoXa, basis, enp and exp similar to those of female. P3. Frontal surface of intercoxal sclerite bare, caudal one with transversal row of minute spinules. distal prominences with 3‒5 minute spinules (Fig. 9C). CoXa, basis, enp and eXp similar to those of female. P4. Frontal surface of intercoxal sclerite bare, caudal one with transversal row of minute spinules and distal prominences with 3‒5 minute spinules (Fig. 9D). CoXa, basis, enp and eXp similar to that of female; apical spine on enp-2 ca 0.8× as long as segment. P5 (Fig. 9E‒F). Similar to that of female, yet outer seta on free segment short, ca 2.3× as long as inner spine. P6 (Fig. 9G). Reduced to cuticular plate with two elements, inner (ventral) one spine and outer (dorsal) one seta; inner spine ca 0.5× as long as outer seta. Variability The body length of the female specimens varies in a range of 0.73–0.75 mm (n = 3) and that of the male specimens is 0.62–0.67 mm (n = 3). The variations in the length/width ratio of caudal ramus in the female, along with the length of spine on the female P5 and the male P6 are shown in Table 2. Distribution Metacyclops sakaeratensis sp. nov. has been known only from the type-locality.Published as part of Athibai, Sujeephon, Wongkamhaeng, Koraon & Boonyanusith, Chaichat, 2022, Two new species of Metacyclops Kiefer, 1927 (Copepoda, Cyclopoida) from Thailand and an up-to-date key to the species recorded in Asia, pp. 146-181 in European Journal of Taxonomy 787 (1) on pages 149-161, DOI: 10.5852/ejt.2021.787.1621, http://zenodo.org/record/583767
Siamcyclops cavernicolus Boonyanusith & Sanoamuang & Brancelj 2018, gen. et sp. nov.
No full textSiamcyclops cavernicolus gen. et sp. nov. urn:lsid:zoobank.org:act:33DF0C7F-AFB6-409A-A5B3-45ED0664B27C Figs 1–5 Etymology The specific epithet cavernicolus meaning ‘organism living in a cave’, indicates its habitat. The epithet is a noun in the nominative singular masculine. Material examined Holotype THAILAND: ♀ (adult), 414 µm long, Ratchaburi Province, Chom Phon Cave, 13°37′32.1″ N, 99°35′14.2″ E, 100 m a.s.l., filtering bottle, 21 Nov. 2009, C. Boonyanusith leg., completely dissected then mounted on a slide in glycerol and sealed with nail polish (NHM 2011.2080). Allotype THAILAND: ♂ (adult), 394 µm long, collected with the holotype, completely dissected, mounted on a slide in glycerol and sealed with nail polish (NHM 2011.2081). Paratypes THAILAND: 2 ♀♀ without egg sacs, 1 ♀ with spermatophore, sampled with the holotype, whole specimens stored in 70% alcohol (NHM 2011.2082‒2084); 1 ♀ with spermatophore and egg sac, 1 ♀ with spermatophore, 2 ♀♀ without egg sacs, sampled with the holotype, whole specimens stored in 70% alcohol (KKU-COP-2011-002); 2 ♀♀, 2 ♀♀ with egg sac, sampled with the holotype, whole specimens stored in 70% alcohol (NIB). Type locality The Chom Phon Cave is located in Chom Bung district, about 30 km west of the town of Ratchaburi. The cave is located in an isolated, small, limestone hill. It is a fossil cave, about 290 m long, with horizontal galleries only and the origin of the sampled water is exclusively drips of percolating water from the epikarst. The cave has two major openings. The first is an entrance located about 10 m above the valley floor at an elevation of 100 m a.s.l. The coordinates of the entrance are 13º37′32.1″ N, 99º35′14.2″ E. Beyond the entrance is a long horizontal gallery at the same level as the valley floor and accessible without any special equipment except a lamp. The gallery is about 10 m wide and 8–10 m high and was formed by a subterranean river. The second opening, about 25 m in diameter, is located above the end-hall of the cave. There is a reclining Buddha statue and in a semi-illuminated place there are several plastic and aluminium buckets (= Buddha pots according to Brancelj et al. 2010) collecting dripping water from the cave walls and roots of trees for the whole year around. This is the type locality of Siamcyclops cavernicolus gen. et sp. nov. On the sampling date (21 Nov. 2009), no water was dripping from the cave walls or tree roots. The volume of water in the plastic buckets was about 5 l and had a brown colour. The water temperature was 23.8°C, pH 8.74, and conductivity 435 µS cm-1. There was some guano and other organic debris in the buckets. Description Female Body length, measured from tip of rostrum to posterior margin of caudal rami, 391‒414 µm (mean: 404 µm; n = 10); prosome/urosome ratio about 2.0 (Fig. 1A). Body dorsoventrally compressed. Preserved specimens transparent; naupliar eye not discernible; rostrum small, triangular. Cephalothorax anteriorly oval, as long as wide, with greatest width at posterior end of cephalosome; representing 41% of body length. Posterior margins of Pd1–Pd4 smooth. Integument smooth, not strongly chitinized, with no visible cuticular windows. Body width/length ratio 2.4. Genital double-somite well developed, about 1.4 times as wide as long, with pair of refractile, sclerotized, rounded, dorsolateral lobes (Fig. 1C); as long as following urosomites, including caudal rami; with well-discernible incision between anterior and posterior half of segment and tapering posteriorly (Fig. 1A–C). Copulatory pore small, oval, situated near middle of somite; copulatory duct short, narrow and well sclerotized. Seminal receptacle small, representing about ⅓ of double-somite length, with anterior and posterior expansions; both expansions short but anterior one slightly longer, sclerotized and much wider compared to posterior one (Fig. 1B). Ovipores situated lateroposteriorly at about ½ length of somite, covered with reduced P6 (Fig. 1D). Posterior margin of genital double-somite and two subsequent somites with hyaline fringes with irregular serration both ventrally and dorsally. Anal somite with well developed operculum, reaching ½ length of caudal rami; distal half of free margin serrated; two large sensilla at base of operculum (Fig. 1C). CAUDAL RAMI (Fig. 1B–D). Slightly divergent; each about 1.5 times as long as wide. Anterolateral accessory seta (I) reduced. Anterolateral seta (II) bare, implanted at ⅔ length of ramus; slightly shorter than ramus. Posterolateral seta (III) slim, about 1.2 times as long as ramus, implanted at ¼ of ramus length; insertion of seta ornamented with few spinules. Outer apical seta (IV) plumose; inner apical seta (V) longest; both setae bipinnatae, without fracture planes; inner one about twice as long as outer one and about 0.5 times as long as body. Apical accessory seta (VI) bare, spiniform, curved outward; about 0.5 times as long as ramus. Dorsal seta (VII) bipinnate, inserted at distal inner corner of ramus, about twice as long as ramus. ANTENNULE (Fig. 1E). 11-segmented, not reaching posterior margin of cephalothorax. Armature formula: 6.2.5.2.0+I.2.3.2+A.2.2+A.7+A. Fifth segment with short spine ventrally. Penultimate segment with aesthetasc near insertion of outer seta; aesthetasc as long as outer seta. Terminal segment with acrotheck subapically. ANTENNA (Fig. 2A). 4-segmented; with coxobasis and 3-segmented Endp. Coxobasis with one smooth seta on distal inner corner; seta representing Exp absent. Endp-1 with longitudinal row of spinules along distal half of inner margin; with one smooth seta at ½ length of margin. Endp-2 about 1.5 times as long as wide, with longitudinal row of minute spinules; along inner margin five smooth setae increasing in length (three laterally, one subapically, one apically). Endp-3 twice as long as wide, with longitudinal row of minute spinules; seven smooth setae apically (two of them robust and curved). MANDIBLE (Fig. 2B–C). With coxa and short basis partly fused with coxa. Gnathobase with strong chitinized teeth; ventralmost teeth very robust and slightly obtuse, with pinnate seta dorsally. Basis with one short and two long setae representing Exp and Endp, respectively; long setae about seven times as long as short seta. MAXILLULE (Fig. 2D). With robust praecoxa and 2-segmented palp; proximal segment of palp coxobasis; distal one Endp. Arthrite of praecoxa with six strong spines laterally, five of them smooth; apically three claw-like spines decreasing in length and one weak seta. Coxobasis with three elements; one robust bipinnate seta accompanied by two weak smooth setae apically. Endp with two setae apically and one seta subapically. Exp represented by one seta. MAXILLA (Fig. 2E). 5-segmented. Endite of praecoxa prominent, with two plumose setae. Proximal endite of coxa with one plumose seta; distal endite elongate, with two bipinnate setae apically. Basis with clawlike basal endite, with row of spinules along concave margin; two setae at base of claw-like expansion; longest one as long as claw; other one shorter, 0.5 times as long as longer one. Endp 2-segmented; proximal segment with two robust setae; distal segment with one robust seta apically, as long as clawlike expansion on basis, accompanied by two slender, shorter setae. MAXILLIPED (Fig. 2F). 4-segmented; syncoxa and basis with two pinnate setae each; basis with one row of spinules on distal outer margin; additional row of spinules laterally. Proximal segment of End with one strong seta. Distal segment armed with three setae, shortest one smooth. P1–P4. With un-ornamented intercoxal sclerite, with deeply concave posterior margins; coxa rectangular; basis relatively triangular with slender outer seta; 2-segmented Exp and Endp (Fig. 3A–D). Coxa of P1– P3 each armed with one plumose seta on inner distal corner. Exp-2 spine/seta formula: 3.3.3.2/5.5.5.5. Endp-2 spine/seta formula: 1.1.1.1/4.4.5.4. Complete armature of P1–P4 as follows (Roman numbers = spines; Arabic numbers = setae): P1 (Fig. 3A). Exp-1 with one smooth, blunt, curved spine on outer corner. Exp-2 about twice as long as wide, apical setae as long as Exp-1 and -2 combined. Endp-1 shorter than wide, with sharply pointed extension on distal outer corner. Endp-2 1.3 times as long as wide, with one seta between 2 claw-like extensions on outer margin; very strong, blunt, hook-shaped spine apically. P2 (Fig. 3B). Similar to P1, slightly less robust; apical spine on Endp-2 only slightly curved, as long as segment bearing it. Exp-2 1.5 times as long as wide. P3 (Fig. 3C). Coxa, basis and Exp similar to those of P2. Endp-2 1.5 times as long as wide; terminal spine on Endp-2 straight, as long as segment bearing it. P4 (Fig. 3D). Exp-2 twice as long as wide, with relatively weak pinnate spines on outer margin; apical setae longer than Exp-1 and 2 combined. Endp-1 large, 1.5 times as wide as long. Endp-2 1.3 times as long as wide, with short apical setae, only slightly longer than segment bearing them; apical spine short, about 0.5 times as long as segment bearing it. P5 (Figs 1B–D, F–G, 2G–H). Reduced to 2 cuticular lobes, completely fused to Pd5, with three slender setae. Dorsal lobe broad, with one seta; ventral lobe small, with two unequal setae apically; longer seta about twice as long as shorter one. P6 (Fig. 1D). Small, forming simple cuticular plate, inserted laterodorsally on genital double-somite, with two minute spines ventrally and one short seta dorsally. SPERMATOPHORE (Fig. 2G–H). Paired; each forming 3-dimensional structure running in anterior-posterior direction ventrally, bending laterally at level of seminal receptacle and bending dorsally (as double flipped L); walls very thick. EGG SAC (Fig. 1A). Extruded from gonopores laterodorsally, with two large eggs. Male Body length, measured from tip of rostrum to posterior margin of caudal rami, 381‒402 µm (mean: 391 µm; n = 10); prosome/urosome ratio about 2.0. Habitus (Fig. 4A) slightly smaller and more slender than in female. Naupliar eye not discernible; rostrum as in female. Cephalothorax and Pd 2–4 similar to those of female. Cephalothorax anteriorly oval, 1.1 times as long as wide, with greatest width at posterior end, representing 43% of body length. Posterior margins of Pd1‒Pd4 smooth. Body length/width ratio about 2.3. Genital somite large, globular, about 0.9 times as long as rest of urosome, including caudal rami (Fig. 4A–D). Hyaline structures on dorsolateral part of genital somite well developed (Fig. 4A–D). Posterior border of genital somite with broad hyaline fringe with irregular serration dorsally. Subsequent three urosomites narrower than genital somite, with irregular serrated free hyaline fringes posteriorly. Anal somite and operculum as in female (Fig. 4A–D). CAUDAL RAMI (Fig. 4B–D). More slender than in female, about 1.6 times as long as wide. Anterolateral accessory seta (I) reduced.Anterolateral seta (II) bare, implanted at about ½ length of ramus, slightly shorter than ramus. Posterolateral seta (III) bipinnate, about 1.2 times as long as ramus; insertion ornamented with few spinules. Outer apical seta (IV) plumose; without fracture plane. Inner apical seta (V) longest, plumose, about twice as long as seta IV and about 0.5 times as long as body length, without fracture plane. Apical accessory seta (VI) bare, spiniform, curved outward; about 0.5 times as long as ramus. Dorsal seta (VII) bipinnate, inserted at distal inner corner of ramus, about twice as long as ramus. ANTENNULE (Fig. 4E). 15-segmented, geniculate. Armature formula: 7+3A.4.2.2+A.1.2+A.3.1+A+I.2.2.2.2+A.1.1.7+A. Terminal segment with acrotheck; short spine on eighth segment. Seta on ninth and eleventh segments robust, spiniform; seta on tenth, eleventh and twelfth segments very short, bipinnate. ANTENNA, MOUTHPARTS, P1, P2 AND P5. As in female. P3 (Fig. 5A). Exp as in female. Endp-2 with apical spine modified as spoon-like element; bent inward and ornamented with minute transverse denticles along distal ⅓ of margin; tip of spine bent. Inner subterminal seta modified as claw-like spine, bare and bent toward apical spoon-like spine. Sub-terminal seta on outer margin very short. P4 (Fig. 5B). Exp and Endp similar to those of female; Endp with relatively longer setae and spines compared to female. P6 (Fig. 4B‒C). Positioned ventrally; modified to large cuticular plate with three setae; middle one shortest; ventral one longest. Variability No significant variability was observed in females except minor variation in size, shape and number of spinules on some segments or somites. Variability not observed in males. Differential diagnosis and remarks Based on the number of segments of the antennules, the progressive oligomerization of P1–P4, and the shape and armature of P5, Pesce (1996) classified 33 genera in the subfamily Cyclopinae into 6 groups, including the Bryocyclops and Microcyclops groups, both presented in this paper. Most of the 33 classified genera also include stygobiotic members. Their morphological adaptations for life in subterranean habitats are related to specific environmental characteristics (i.e., lack of light and food scarcity) and include a reduction of body size, 10- or 11-segmented antennules, P1–P4 with three or two segmented Exp, two or one segmented Endp rami, and partly or completely fused P5 to Pd5. The level of reductions express a grade of a transformation of appendages from a plesiomorphic state (P1–P4 with three segmented Exp/Endp and P5 clearly separated from Pd5) to an apomorphic one (P1–P4 with reduced number of segments in Exp/Endp and P5 fused with Pd5) (Pesce 1996). In stygobiotic Cyclopinae, intensive reductions of P5 have a strong effect on establishing a genus level (Reid & Ishida 2000). For that reason, some other morphological characters should also be included to support the erection of a new genus as well as its position within six groups in the subfamily Cyclopinae. Examples of the effect of inclusion of other morphological characters in erecting a new genus and its positioning within six gropus of Cyclopinae include the morphologicaly similar genera Speocyclops Kiefer, 1937 (a member of Microcyclops group) and Bryocyclop s Kiefer, 1927 (a member of Bryocyclops group). They are similar in body shape and both have very reduced P5 or even have it fused to Pd5 (Pandourski 1992; Dussart & Defaye 2001; Galassi & De Laurentiis 2004). The main discrimination character between both genera/groups is the presence/absence of a seta on the inner corner of the coxa in P4. In the genus Bryocyclops it is absent, while in the genus Speocyclops it is present. There are some similar morphological details between the Microcyclops and Bryocyclops groups, also. An example is the modification of the P3 Endp-2 spine in the males observed in representatives of Bryocyclops and the Alaskan population of Itocyclops yezoensis (Itô, 1953) (member of the Microcyclops group). However, according to Reid & Ishida (2000), there are no phylogenetic relationships between the genera Bryocyclops and Itocyclops Reid & Ishida, 2000, and the modification of P3 might be a result of random mutation within the Alaskan population. Absence of a seta on the inner corner of the coxa in P 4 in the male and female as well as the modification of the P3 Endp-2 spine in the male place Siamcyclops gen. nov. in the Bryocyclops group. So far, representatives of genera Bryocyclops and Siamcyclops gen. nov. only differ from other genera within the Bryocyclops group by morphological modifications in armature elements on the male P3 Endp-2. The lack of a seta on the inner corner of the coxa of P 4 in the male and female, combined with modifications of elements of the P3 Endp- 2 in the male, indicate a close relationship between S. cavernicolus gen. et sp. nov. and the representatives of Bryocyclops groups I, II, V and VII (in group VII it is not modification but a difference in the size of the spine between the male and female) (Lindberg 1956; Reid 1999; Fiers 2002; Watiroyram et al. 2015). A similarity in the shape of the P4 Endp-2 and the presence of six armature elements there (five in other Bryocyclops species) indicate that the new taxon most resembles B. jankowskajae Monchenko, 1972, known from the Kyzylkum Desert in Uzbekistan (formerly part of the USSR). The species was recently moved from the subgenus Palaeocyclops Monchenko, 1972 into Bryocyclops s. str. (Walter 2015). For that reason, we suggest the establishment of a new group, i.e., group VIII, to accommodate it within the genus Bryocyclops. All representatives of the genus Bryocyclops (except B. bogoriensis (Menzel, 1926)) and the former member of the subgenus Palaeocyclops have a pointed prominence on the intercoxal sclerite of P4, while in S. cavernicolus gen. et sp. nov. it is obtuse. However, the armament on the mandibular palp and distal segment of P4 Exp found in representatives of the genus Bryocyclops, including a former member of the subgenus Palaeocylops, show a pattern of reduction of armature elements. The presence of only one or no seta can be observed in several species within the genus Bryocyclops where the mandibular palp was described or illustrated, as in B. saqotraensis Mirabdullayev, Van Damme & Dumont, 2002, B. muscicola (Menzel, 1926), B. maewaensis Watiroyram, Brancelj & Sanoamuang, 2012 and B. jankowskajae. The presence of 3 setae on the mandibular palp in S.cavernicoulus gen. et sp. nov. shows a plesiomorphic state of the character, which clearly differentiates it from members of the genus Bryocyclops. Furthermore, the spine/seta formula 3.3.3.2/5.5.5.5 found in the new taxon differs clearly from the formulae of the species within the genus Bryocyclops, where the spine/seta formula varied from 2.2.2.2/ 5.4.4.3 (group V) to 2.3.3.3/ 5(4).4.4.3 (group VI), 3.3.3.2/5.4.4.4 (group III), 3.3.3.3/ 5.5.5.4 (groups I and VII), 3.3.3.3(4) /5(4).5.5.4 (group II), and 3.3.3.4 /5.4.4.4 (group IV) (Lindberg 1947; Watiroyram et al. 2015). It also differs considerably from B. jankowskajae whose spine/setae formula is 2.3.3.3/ 5.5.5.4. Normally, the spermatophores within the subfamily Cyclopinae are bean- or kidney-shaped. They have also been illustrated in some species of Bryocyclops such as B. caroli Bjornberg, 1985 and B. absalomi Por, 1981. The unique, three dimensional L-flip feature of the spermatophore observed in S.cavernicolus gen. et sp. nov. differs from those of other members of the genus Bryocyclops as well as from other members of the subfamily Cyclopinae. For the reasons listed above, we propose the establishment of the new genus Siamcyclops gen. nov. to accommodate the new stygobiotic species from Thailand. The main differences between the three related taxa, Bryocyclops spp., Bryocyclops jankowskajae and Siamcylops gen. nov., are listed in Table 1.Published as part of Boonyanusith, Chaichat, Sanoamuang, La-orsri & Brancelj, Anton, 2018, A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups, pp. 1-30 in European Journal of Taxonomy 431 on pages 4-14, DOI: 10.5852/ejt.2018.431, http://zenodo.org/record/125496
Fig. 7 in A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups
No full textFig. 7. Metacyclops thailandicus sp. nov., holotype, ♀. A. Antennule. B. Antenna. C. Mandible. D. Maxillule. E. Maxilla. F. Maxilliped. Scale bars: 100 μm.Published as part of Boonyanusith, Chaichat, Sanoamuang, La-orsri & Brancelj, Anton, 2018, A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups, pp. 1-30 in European Journal of Taxonomy 431 on page 19, DOI: 10.5852/ejt.2018.431, http://zenodo.org/record/125496
Fig. 1 in A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups
No full textFig. 1. Siamcyclops cavernicolus gen. et sp. nov., holotype, ♀. A. Habitus, with spermatophores and egg sac, dorsal view. B. Urosome, ventral view. C. Urosome, dorsal view. D. Urosome, lateral view. E. Antennule. F. P5, ventral view. G. P5, lateral view. Scale bars: 100 μm.Published as part of Boonyanusith, Chaichat, Sanoamuang, La-orsri & Brancelj, Anton, 2018, A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups, pp. 1-30 in European Journal of Taxonomy 431 on page 7, DOI: 10.5852/ejt.2018.431, http://zenodo.org/record/125496
Fig. 3 in A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups
No full textFig. 3. Siamcyclops cavernicolus gen. et sp. nov., holotype, ♀. A. P1. B. P2. C. P3. D. P4. Scale bar: 100 μm.Published as part of Boonyanusith, Chaichat, Sanoamuang, La-orsri & Brancelj, Anton, 2018, A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups, pp. 1-30 in European Journal of Taxonomy 431 on page 10, DOI: 10.5852/ejt.2018.431, http://zenodo.org/record/125496
Fig. 4 in A new genus and new species of stygobitic copepod (Crustacea: Copepoda: Cyclopoida) from Thien Duong Cave in Central Vietnam, with a redescription of Bryocyclops anninae (Menzel, 1926)
No full textFig. 4. Pseudograeteriella longiaesthetascus new genus, new species, male. A, habitus, dorsal view; B, genital somite, ventral view; C, antennule; D, Endp-2 of P4. Scale bars: A, 250 μm; B–D, 100 μm.Published as part of Sanoamuang, La-orsri, Boonyanusith, Chaichat & Brancelj, Anton, 2019, A new genus and new species of stygobitic copepod (Crustacea: Copepoda: Cyclopoida) from Thien Duong Cave in Central Vietnam, with a redescription of Bryocyclops anninae (Menzel, 1926), pp. 189-205 in Raffles Bulletin of Zoology 67 on page 197, DOI: 10.26107/RBZ-2019-0016, http://zenodo.org/record/457578
Fig. 1 in A new genus and new species of stygobitic copepod (Crustacea: Copepoda: Cyclopoida) from Thien Duong Cave in Central Vietnam, with a redescription of Bryocyclops anninae (Menzel, 1926)
No full textFig. 1. Pseudograeteriella longiaesthetascus new genus, new species, female. A, habitus, dorsal view; B, rostrum, frontal view; C, genital double-somite, dorsal view; D, urosome, ventral view; E, genital double-somite, lateral view; F, caudal rami, dorsal view; G, caudal ramus, lateral view. Scale bars: A, 250 μm; B, 50 μm; C–G, 100 μm.Published as part of Sanoamuang, La-orsri, Boonyanusith, Chaichat & Brancelj, Anton, 2019, A new genus and new species of stygobitic copepod (Crustacea: Copepoda: Cyclopoida) from Thien Duong Cave in Central Vietnam, with a redescription of Bryocyclops anninae (Menzel, 1926), pp. 189-205 in Raffles Bulletin of Zoology 67 on page 192, DOI: 10.26107/RBZ-2019-0016, http://zenodo.org/record/457578
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