taxonID	type	description	language	source
419AFFD80FF65E5E830A4C4A1982D1D7.taxon	description	Figs 1, 2, 3, 4, 5, 6	en	Boonyanusith, Chaichat, Pham, Thi-Phuong, Dam, Minh Anh, Tran, Ngoc-Son, Gómez, Samuel (2025): Mesochra vietnamica sp. nov. (Copepoda, Harpacticoida, Canthocamptidae), the first record of the genus from Vietnam, with a key to Asian species. ZooKeys 1265: 69-86, DOI: 10.3897/zookeys.1265.174622
419AFFD80FF65E5E830A4C4A1982D1D7.taxon	etymology	Etymology. The specific epithet refers to the country where the new species was discovered. The name is an adjective in the nominative singular, gender feminine.	en	Boonyanusith, Chaichat, Pham, Thi-Phuong, Dam, Minh Anh, Tran, Ngoc-Son, Gómez, Samuel (2025): Mesochra vietnamica sp. nov. (Copepoda, Harpacticoida, Canthocamptidae), the first record of the genus from Vietnam, with a key to Asian species. ZooKeys 1265: 69-86, DOI: 10.3897/zookeys.1265.174622
419AFFD80FF65E5E830A4C4A1982D1D7.taxon	description	Description. Female. Habitus (Fig. 1 A) fusiform, widest at the posterior part of the cephalothorax. Total body length measured from anterior margin of rostrum to posterior margin of caudal rami 238 – 288 µm (mean = 263 µm, n = 6; length of holotype = 261 µm). Rostrum (Figs 1 A, 2 A) large, broad, triangular, with rounded apex, with two subdistal lateral sensilla. Prosome gradually tapering from posterior part of cephalothorax to posterior part of P 4 - bearing somite; all prosomites with smooth posterior hyaline frill and with sensilla as shown. P 5 - bearing somite narrower than preceding somite, with smooth posterior hyaline frill and with fewer sensilla. Second (genital) and third urosomites fused dorsally forming genital double-somite (Fig. 1 A, C, D), with ventrolateral vestige of division between somites (Fig. 1 B, D); posterior half of genital double-somite with dorsal row of small spinules interrupted dorsally, with longer ornaments laterally, and with medial row of small spinules ventrally (Fig. 1 B – D); anterior and posterior halves with dorsal pores as shown (Fig. 1 C); genital complex (Fig. 1 D) with narrow small copulatory pore medially, posterior to genital apertures. Fourth urosomite (Fig. 1 B – D) resembles posterior half of genital double-somite. Fifth urosomite (Fig. 1 B – D) without sensilla or spinules dorsally, with few long spinules laterally and two sets of three spinules ventrally. Anal somite (Fig. 1 B – D) with row of small spinules dorsally and more robust ornamentation ventrally, and two spinules laterally; semicircular anal operculum with row of spinules along free margin and one sensilla on each side; ventrally cleft, with longitudinal spinules as shown. Caudal ramus (Fig. 1 A – D) subquadrate, about as long as wide; with six elements as follows: anterolateral seta (I) absent, anterolateral seta (II) smooth, inserted at about ½ length of outer margin, flanked by two strong spinules; posterolateral seta (III) smooth, inserted in outer distal corner, about 2.6 times as long as caudal ramus; outer distal seta (IV) about 6.3 times as long as caudal ramus, unipinnate; inner terminal seta (V) strong, longest, pinnate; inner accessory seta (VI) thin and smooth, about 2.2 times as long as caudal ramus; dorsal seta (VII) about 1.5 times as long as caudal ramus, smooth, triarticulated, inserted at 2 / 3 of caudal ramus length, inserted close to inner margin. Antennule (Fig. 2 A) 6 - segmented. First segment with row of spinules proximally and distally. Second segment with row of spinules dorsally and along inner margin. Second and third segments with one and two unipinnate spiniform setae, respectively. Aesthetasc on third segment reaching far beyond distal segment. Setal formula as follows: 0, 7, 9 + ae, 1, 2, 5 + acrothek. Antenna (Fig. 2 B) with coxa bearing one spinule. Allobasis 1.7 times as long as wide, with two abexopodal bare setae. Exopod 1 - segmented, with three apical setae: one subdistal pinnate seta; apically with one pinnate and one bare seta different in length. Endopodal segment with spinules along inner margin proximally, two strong lateral spines and five elements apically: one geniculate pinnate and two smooth geniculate setae, and two smooth spines. Mandible (Fig. 2 C) with robust coxa bearing five strongly chitinized teeth and one seta. Mandibular palp 2 - segmented; first basal segment with several spinules along outer margin, one pinnate seta on inner margin and one short spiniform exopodal seta; endopod with one pinnate seta on inner margin and apically with three pinnate setae unequal in length. Maxillule (Fig. 2 D) Praecoxal arthrite with one small surface seta, eight large robust spines apically, and one robust, unipinnate seta at ¾ of inner margin; with rows of spinules as shown. Coxa and basis fused; coxal endite with one spiniform seta and with outer row of spinules. Basis with proximal row of outer spinules, with two subdistal lateral setae, and two distal setae and one spiniform element apically; with four elements representing remnant of endopod and exopod. Maxilla (Fig. 2 E) composed of syncoxa and allobasis. Syncoxa with two endites; each endite with two spiniform and one smooth seta apically. Allobasis drawn out into bare, strong claw, with five smooth setae near its base (three of which probably endopodal). Maxilliped (Fig. 2 F) comprising syncoxa, basis, and Enp. Syncoxa with an anterior row of small spinules at ½ segment length, and row of small spinules at the base of spiniform unipinnate seta on inner margin apically. Basis about 2.2 times as long as wide, with longitudinal row of spinules along inner margin. Endopod with smooth, curved claw and a small accompanying seta. P 1 – P 4 (Figs 3 A, B, 4 A, B) with short unornamented intercoxal sclerites, except in P 1 with two rows of small spinules on each side. The Exp / Enp length ratio for P 1 – P 4 is 0.6, 1.7, 1.3, and 3.1, respectively. P 1 (Fig. 3 A) coxa with four groups of small spinules unequal in size, and with spinules close to outer distal corner. Basis with anterior surface spinules, with stronger ornaments distally between rami, and at base of outer and inner spines, with setules along inner margin. Exopod 3 - segmented; Exp- 1 with one strong outer spine; Exp- 2 with strong outer spine and slender pinnate inner seta; Exp- 3 with two smooth outer spines and two geniculate distal setae. Endopod 3 - segmented; Enp- 1 reaching beyond Exp, with rows of spinules along inner and outer margin, with a pinnate inner seta inserted at distal third of segment; Enp- 2 shortest, with one thin, smooth inner seta and two outer spinules; Enp- 3 with three elements: one thin and smooth lateral inner seta, one geniculate inner distal seta, and one strong smooth outer distal spine. P 2 (Fig. 3 B) coxa with few spinules close to outer distal corner. Basis with few strong spinules at the base of strong outer spiniform seta, and distally between rami, and with a transversal row of short, hair-like setules on inner margin. Exopod 3 - segmented; segments with spinules on outer margin and setules along inner margin; Exp- 1 with frill on distal inner corner and outer spine; Exp- 2 with frill on distal inner corner, outer spine, and pinnate seta at 2 / 3 length of inner margin; Exp- 3 with three outer spines of which two proximal smooth, distal one unipinnate, two pinnate seta apically and one at ½ length of inner margin. Endopod 2 - segmented, reaching tip of Exp- 2; segments with strong spinules along inner margin, and weak spinules along outer margin; Enp- 1 unarmed; Enp- 2 with five elements: two pinnate setae at ½ and ¾ length of inner margin, two long pinnate setae and one short spine apically. P 3 (Fig. 4 A) coxa with one row of spinules anteriorly, and one on outer distal corner. Basis with spinules at the base of pinnate outer seta, and distally between rami. Exopod 3 - segmented; Exp- 1 and Exp- 2 as in P 2. Exp- 3 as in P 2 except for two pinnate inner setae. Endopod 2 - segmented, almost reaching tip of Exp- 2; Enp- 1 as in P 2; Enp- 2 with five elements: one unipinnate and one pinnate inner seta, two pinnate setae apically, and one unipinnate outer spine. P 4 (Fig. 4 B) coxa with spinules close to outer distal margin. Basis as in P 3. Exopod 3 - segmented; Exp- 1 and Exp- 2 as in P 2 and P 3; Exp- 3 as in P 3 except for subdistal inner seta visibly stronger and with distal fourth unipinnate. Endopod 2 - segmented, reaching tip of Exp- 1; Enp- 1 unornamented, with one bare inner seta; Enp- 2 with five elements: one stiff proximal and one subdistal seta on inner margin, two pinnate setae apically, and one unipinnate outer spine. Armature formula of P 1 – P 4 as in Table 2. P 5 (Fig. 1 E) exopod and baseoendopod separated. Exopod with few spinules along inner and outer margin; with five elements: two short and smooth setae on outer margin, one smooth seta subapically, one long pinnate seta apically, one pinnate seta on inner margin; length ratio of the setae from inner to outer 1: 3.8: 1: 0.4: 0.6. Baseoendopod with few spinules on outer margin; with five unequal setae: two unipinnate proximal and one pinnate seta along inner margin subapically, and two pinnate setae apically. P 6 (Fig. 1 D) represented by two setae of which inner smooth and outer pinnate. Мale. General body shape (Fig. 5 A) and ornamentation of urosomites (Fig. 5 B – D) as in female. Total body length measured from anterior margin of rostrum to posterior margin of caudal rami 206 – 225 µm (mean = 215 µm, n = 3; length of allotype = 215 µm). Rostrum, anal operculum, and caudal rami as in female. Sexual dimorphism expressed in antennule, urosomal segmentation [second (genital) and third urosomites separated], P 3 Enp, P 5, and P 6. Antennule (Fig. 6 A) 7 - segmented. Surface of segments smooth except for a row of robust spinules on inner distal corner on first segment. All setae smooth, except for one spiniform seta on second and third segments. Aesthetasc on third segment long, reaching far beyond distal segment, and fused basally to slender seta. Setal formula as follows: 0, 6, 11 + ae, 0, 0, 0, 4 + acrothek. P 1, P 2, P 4 (not shown) as in female. P 3 (Fig. 6 B) coxa, basis and exopod as in female Endopod 3 - segmented; Enp- 1 as in female. Enp- 2 unornamented, with inner sinuous apophysis reaching beyond Enp- 3, the latter with two pinnate setae apically of which outer slightly longer. P 5 (Fig. 5 E) exopod and baseoendopod separated; baseoendopod of both legs fused medially. Exopod with spinules along inner margin; with six smooth unequal setae; length ratio of setae from inner to outer 1: 1.2: 3: 1.6: 0.9: 0.9. Baseoendopod with spinules along inner and outer margin; with two spiniform unipinnate setae apically, of which outer shorter. P 6 (Fig. 5 D) represented by smooth simple plate; fused to somite.	en	Boonyanusith, Chaichat, Pham, Thi-Phuong, Dam, Minh Anh, Tran, Ngoc-Son, Gómez, Samuel (2025): Mesochra vietnamica sp. nov. (Copepoda, Harpacticoida, Canthocamptidae), the first record of the genus from Vietnam, with a key to Asian species. ZooKeys 1265: 69-86, DOI: 10.3897/zookeys.1265.174622
