Mongolodiaptomus phutakaensis Sanoamuang & Koompoot, 2024, sp. nov.
Creators: name: Sanoamuang, Laorsri
name: Koompoot, Kamonwan
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Copepoda
Calanoida
Diaptomidae
Mongolodiaptomus
Mongolodiaptomus phutakaensis

description: Mongolodiaptomus phutakaensis sp. nov.
Figs 1, 2, 3, 4, 5, 6, 7, 8
Mongolodiaptomus sp. Sanoamuang and Dabseepai (2021): 7, 18, 20.
Type locality.
A natural swamp in Kok Phutaka community forest, Muang Kao Phatthana Subdistrict, Wiang Kao District, Khon Kaen Province, northeast Thailand (16 ° 38 ' 43.77 " N, 102 ° 18 ' 11.90 " E); elevation 220 m a. s. l., water temperature 31.2 ° C, pH 8.2, conductivity 299 µS cm - 1.
Type material.
Holotype: adult male (THNHM -1V-19371), dissected and mounted in glycerol on one slide. Allotype: adult female (THNHM -1V-19372), dissected and mounted in glycerol on one slide. Paratypes: three adult males and three adult females (THNHM -1V-19373), undissected and preserved in 4 % formalin; collected from the type locality on the same date as the holotype. All specimens were collected on 16 August 2007, by P. Dabseepai and K. Koompoot.
Description of adult male.
Total body length, measured from anterior margin of rostrum to posterior margin of caudal rami, 1.3–1.4 mm (mean = 1.37 mm, n = 10), (Figs 1 A, 2 A). Body smaller and slender than in female. Prosome ~ 2.2 × as long as urosome (Fig. 2 A). Rostrum (Fig. 1 B) well developed, with two spiniform processes. Pedigers 4 and 5 fused except at lateral margins. Lateral wings of Pdg 5 asymmetrical; right postero-lateral wing shorter than left one; each wing with one thin postero-lateral spine (Fig. 2 A).
Urosome (Figs 1 D, 2 A – C) with five somites. Genital somite dilated postero-laterally on right side, shorter than wide, with a curved spine on the right posterolateral corner. Urosomites 2–4 approximately as long as wide each. Urosomites 2–3 (Figs 1 D, 2 B, C) with a patch of hairs on right ventral side. Urosomite 4 with expanded right dorso-posterior margin. Anal somite asymmetrical, right side slightly longer than left side (Fig. 2 A, C). Caudal rami asymmetrical (Figs 1 E, 2 A – C), each ramus ~ 2.3 × as long as wide, inner right margin hairy (Figs 1 E, 2 B). Right ramus armed with four chitinous structures on ventral surface; two sharp tips situated proximally and two semicircular knobs distally (Figs 1 E, 2 B). Each ramus with six setae (setae II – VII): setae II – VI plumose, anterolateral (II) seta with smooth region on outer margin proximally; terminal setae (setae IV and V) without fracture plane; dorsal seta (VII) articulated, bare, longest.
Antennule: asymmetrical, extending beyond the end of caudal setae. Left antennule (Fig. 3 F): 25 - segmented. Armature formula as in Table 1. Right antennule (Figs 1 C, 2 D – F) 22 - segmented. Armature formula as in Table 2. External extension on antepenultimate segment (segment XX) short, comb-like, with five or six teeth (Figs 1 C, 2 F).
Antenna (Fig. 3 A): coxa and basis with one and two bare setae on inner distal corner, respectively. Enp two-segmented; Enp - 1 with two setae along inner margin; Enp - 2 with nine setae along inner margin, seven setae apically; all setae bare. Exp seven-segmented: Exp - 1–6 with 1, 3, 1, 1, 1, 1 setae along inner margin; Exp - 7 with one seta on inner margin and three setae apically; all setae bare.
Mandible (Fig. 3 B): ~ 6 cuspidate teeth dorsally and one seta on coxal gnathobase dorsally. Basis with four bare setae: one proximally and three distally along inner margin. Enp - 1 with four setae on inner distal corner. Enp - 2 with nine setae apically; two oblique rows of spinules along outer margin. Exp - 1–3 each with one seta on inner margin; Exp - 4 with three setae apically; all setae bare.
Maxillule (Fig. 3 C): praecoxal arthrite with nine strong setae laterally and four slender submarginal setae. Coxal endite with four setae; coxal epipodite with nine setae; two proximal-most setae smaller than others. Two basal endites fused to segment bearing them: proximal and distal endite, each with four setae apically; basal exopodite with one short seta. Enp - 1 and Enp - 2 each with four setae apically, proximal segment fused to basis. Exp with six bare setae apically.
Maxilla (Fig. 3 D): praecoxa fused to coxa. Proximal and distal endites on praecoxa with three setae apically each. Two coxal endites with three setae apically each. Allobasis with three setae apically. Enp two-segmented; with three setae each.
Maxilliped (Fig. 3 E): four medial lobes on syncoxa: setal formula 1, 2, 3, 4, respectively; subdistal inner margin produced into a spherical lobe with a patch of tiny spinules. Basis with three setae along medial inner margin, with a row of tiny spinules proximately. Enp six-segmented, with 2, 3, 2, 2, 2, and 4 bare setae, respectively.
P 1 – P 4 (Fig. 4 A – D): coxa with a pinnate seta at innermost distal corner. P 1 and P 2 basis without setae; a reduced bare seta on outer distal margin of P 3 and P 4. Exp longer than Enp; two-segmented Enp and three-segmented Exp on P 1, three-segmented Enp and Exp on P 2 – P 4. Armature formula of P 1 – P 4 as in Table 3.
P 5 (Figs 1 F – K, 5 A, B): intercoxal sclerite trapezoidal, inner distal margin not produced, without any projection. Right P 5: coxa with an acute, robust spine on extension on posterior surface, its tip bent inward (Figs 1 F, 5 A), inner distal margin slightly produced into a rounded lobe. Basis rectangular, ~ 1.5 × as long as wide; with prominent irregular-shaped chitinous process at mid-distal length on posterior surface (Figs 1 F, 5 A); a small seta on distal outer margin; without any hyaline structure. Enp one-segmented, gradually tapering to distal end, tipped with tiny spinules distally; reaching beyond 1 / 3 of Exp - 2. Exp - 1 shorter than wide, with two chitinous knobs at distal inner corner; outer distal margin produced into acute tip (Figs 1 I, 5 A, B). Exp - 2 slightly incurved, inner margin convex, outer margin concave, ~ 2.5 × as long as wide, with two small processes proximally and distally; principal lateral spine inserted slightly posterior to mid-length of outer margin. Principal lateral spine (Figs 1 K, 5 A, B) somewhat slightly curved, robust, ~ 1 / 2 length of segment. Accessory lateral spine (Figs 1 K, 5 A, B) minute, distal spine situated close to insertion of end-claw (Figs 1 I, 5 B), distal accessory spine smaller than proximal one. End-claw sickle-shaped, long, and slender, with a serrate inner margin, with blunt tip; ~ 1.5 × as long as Exp - 2.
Left P 5 (Figs 1 G – J, 5 A, B): coxa with long bare seta on posterior lobe near distal inner corner; longer and slender than spine on right coxal segment. Basis with long narrow hyaline lamella along inner margin (Figs 1 J, 5 A, B); slender, long posterolateral seta on posterior surface, reaching to middle of Exp - 2 segment (Figs 1 H, 5 A, B). Exp - 1 trapezoidal, tapering towards distal end, medial margin concave with a field of setules (Figs 1 H, 5 A, B). Exp - 2 smaller than Exp - 1, with inner robust seta, longer than Exp - 2; with inner strongly serrate margin (Figs 1 H, 5 A, B). Exp - 3 reduced to thumb-like segment. Enp one-segmented, shorter than Exp - 1, with spinulated tip.
Description of adult female.
Total body length, measured from anterior margin of rostrum to posterior margin of caudal rami, 1.5–1.7 mm (mean = 1.6 mm, n = 10) (Figs 6 A, 8 A). Prosome: urosome ratio ~ 2.4: 1. Prosome similar to that of male. Rostrum fused, symmetrical, acutely pointed (Fig. 8 B). Fourth and fifth pedigerous somites incompletely fused. Fifth pediger with sub-asymmetrical posterolateral wings (Figs 6 A, C, 8 C); right wing rounded, left wing triangular and longer than right wing. Urosome 3 - segmented, with asymmetrical genital double-somite (Fig. 6 A – C). Genital double-somite longer than urosomite 2, anal somite, and caudal rami combined (Figs 6 B, C, 8 C); right proximal region slightly curved with small spine. Left side with large dorsolateral spine on sub-proximal region. A pair of gonopores and copulatory pores located centrally at ~ 1 / 2 length of genital double-somite (Figs 6 B, 8 H). Urosomite 2 symmetrical, shorter than wide. Anal somite symmetrical, as long as length of caudal rami (Figs 6 C, 8 I); anal operculum small with convex free margin. Caudal rami parallel, symmetrical; both rami with hairy inner and outer margins (Figs 6 C, 8 I). All principal caudal setae slightly dilated anteriorly; dorsal seta approximately as long as principal setae.
Antennule symmetrical; left antennule, antenna, mouthparts, and P 1 – P 4 as in male.
P 5 symmetrical (Figs 7 A, B, 8 D – G). Intercoxal sclerite narrow, triangular. Distal outer margin of coxa extended on anterior side into spiniform apophysis reaching distal part of Exp - 1 (Fig. 7 B). Basis with thin, bare seta on outer margin, reaching ~ 1 / 4 of Exp - 1 length. Exp three-segmented (Figs 7 A, B, 8 E, F). Exp - 1 sub-rectangular, ~ 2.3 × as long as wide. Exp - 2 triangular, with a row of strong spinules along both margins; with longitudinal grooves (conveyor canals) on posterior view (Figs 7 A, 8 D), small outer spine proximally. Exp - 3 reduced, represented by a small segment on proximal outer margin of Exp - 2, armed with two unequal spiniform setae apically. Enp two-segmented (Fig. 8 G), subconical, ~ 2 / 3 as long as Exp - 1; with obliquely truncate and finely spinulose apex.
Etymology.
The specific epithet is derived from Kok Phutaka, reflecting the name of the area in which the type locality is located. The name is an adjective in the nominative singular, gender feminine.
Distribution.
At present, the new species has been found only in the type locality, a natural swamp in Kok Phutaka community forest in Khon Kaen Province, northeast Thailand. It co-exists with other calanoids, Phyllodiaptomus praedictus Ranga Reddy & Dumont, 1994 and Mongolodiaptomus rarus (Ranga Reddy, Dumont, & Sanoamuang, 1998). The other artificial ponds nearby also contained M. botulifer (Kiefer, 1974). Representatives of the new species were observed only once out of approximately 5,000 sampled sites throughout Thailand. Currently, this species is endemic to Thailand. The new species is present in only one locality throughout the year, and ecological parameters varied in a temperature range of 25.0–32.5 ° C (mean = 29.13 ° C), conductivity 74–495 µS cm - 1 (mean = 201.25 µS cm - 1), and pH 5.16–10.03 (mean = 7.66).
description: Published as part of Sanoamuang, Laorsri & Koompoot, Kamonwan, 2024, A description of a new species of Mongolodiaptomus Kiefer, 1937 (Copepoda, Calanoida, Diaptomidae) from Thailand with an up-to-date key to the genus, pp. 19-42 in ZooKeys 1209 on pages 19-42, DOI: 10.3897/zookeys.1209.125838