Asiagomphus kosterini, Kompier, 2018

Kompier, Tom, 2018, The genus Asiagomphus in Vietnam, with descriptions of three new species, and first descriptions of the male of Asiagomphus auricolor (Fraser, 1926) and of the female of Asiagomphus reinhardti Kosterin & Yokoi, 2016 (Odonata: Gomphidae), Zootaxa 4462 (3), pp. 301-330 : 308-315

publication ID	https://doi.org/ 10.11646/zootaxa.4462.3.1
publication LSID	lsid:zoobank.org:pub:75D121A7-F718-4F69-9E33-E82AB371403A
DOI	https://doi.org/10.5281/zenodo.5974767
persistent identifier	https://treatment.plazi.org/id/03C887DB-6062-8C0F-FF67-D3BF1D7DFE0A
treatment provided by	Plazi
scientific name	Asiagomphus kosterini
status	sp. nov.

Treatment

Asiagomphus kosterini View in CoL sp. nov.

( Figs. 3c–d, h View FIGURE 3 , 5f View FIGURE 5 , 6f View FIGURE 6 , 7f View FIGURE 7 , 8d View FIGURE 8 , 11f View FIGURE 11 , 12h View FIGURE 12 , 13c View FIGURE 13 )

Material examined: Holotype ♂, Da lat, Lam Dong Prov., (appr. 11.880 N, 108.442 E), 17-IV-2016, TK leg. GoogleMaps

Paratype. 1 ♂, Bidoup - Nui Ba NP, Lam Dong Prov., central Vietnam, alt. 1,430 m, 07-VI-2017, V.Q. To leg.

Additional records based on field observations: 9 ind., Da Lat , Lam Dong Prov., 17-IV-2016, TK ; 3 ♂♂, same location, 18-IV-2016, TK ; 1 ♂, Nam Bang Protection Forest , Lam Dong Prov., central Vietnam, alt. 1,315 m, 17-II-2017, V.Q. To.

Etymology. The specific name kosterini , a noun in the genitive case, refers to Dr. Oleg E. Kosterin, an entomologist who has worked extensively on Odonata , in particular in Cambodia, and as such has described many species also occurring in southern Vietnam. A recent example is Asiagomphus reinhardti Kosterin & Yokoi, 2016 .

Description of holotype ( Figs. 3c–d View FIGURE 3 , 5f View FIGURE 5 , 6f View FIGURE 6 , 7f View FIGURE 7 , 8d View FIGURE 8 , 11f View FIGURE 11 , 12h View FIGURE 12 ).

Head. Lateral lobes of labium bright yellow, median lobe black. Labrum black with two oblong yellow spots at the dorso-lateral corners just below the dorsal margin. Anteclypeus black, somewhat browner in the middle. Postclypeus black, but laterally dark brown. Base of mandibles bright yellow. Postfrons with broad yellow stripe, extending downward to cover the dorsal half of the otherwise black antefrons. Posterior edge of postfrons black. Cranium black, lateral ocelli with a raised ridge posteriorly and small nipple like protrusion laterally. Occiput blackish brown, smooth but slightly raised centrally, occipital ridge with long black hairs. Antennae black, but top of first segment pale.

Thorax. Prothorax black, but anterior lobe with central yellow spot extending all the way laterally along anterior margin, and median lobe with yellow central spot and pair of lateral spots and a tiny yellow spot between these larger markings, and a similarly tiny yellow spot at center of posterior lobe. Synthorax black with yellow markings as follows: Mesepisternum with dorsal stripe, straight, but slightly constricted just before merging sublaterally with collar stripe to form two inverted and non-symmetrical “T” shapes. Small antehumeral spot towards dorsal end of humeral suture. Blackish brown mesepimeron with straight broad lateral stripe. Mesokatepisternum blackish with large yellow mark. Metepisternum blackish brown with yellow spot at posterodorsal corner, somewhat paler smudge at posterior margin centrally and yellow somewhat kidney-shaped marking posterior of spiracle. Metakatepisternum yellow with brownish smudges along margins. Metepimeron almost completely yellow, but black stripe over metapleural suture. Coxae yellow and legs all black.

Abdomen. Black with yellow markings as follows: S1 ventral half yellow and dorsal half black, center of dorsum yellow; dorso-laterally covered in long black hairs; S2 with yellow auricle, yellow along venter, which extend upward laterally before black posterior margin, and with yellow central line dorsally; S3 with triangular antero-ventral spot and complete dorsal stripe; S4–6 with short antero-dorsal stripe and anterolateral spot, not connected to form half-ring; S7 with antero-dorsal half-ring, somewhat constricted in middle, and yellow triangle postero-laterally; S8 with pair of large postero-lateral spots, extending almost completely sublaterally to anterior margin; S9 with large yellow marking on posterior half of which the anterior edge is very irregular, constricted in the middle and again sublaterally, not quite reaching lateral margin, also a small yellow mark on the anterolateral corner; S10 with a pair of yellow spots dorso-laterally towards the posterior margin. S7 somewhat and S8–9 markedly widened.

Accessory genitalia ( Figs. 3c–d View FIGURE 3 ). Anterior hamulus yellowish brown, about 4x longer than wide, apical third constricted, minimally curved inwards and posteriorly at apex, postero-lateral margin of constricted part black with series of small teeth. Posterior hamulus black, robust, in lateral view 3x length of visible part of anterior hamulus, lateral surface constricted at one third from base, then flat towards apex, apex curved to form robust hook directed anteriorly and downward at 45 degree angle.

Vesica spermalis . Flagellum extending well beyond somewhat slender median process of apical segment, tip of flagellum extended downward at 45 degree angle.

Wings. Hyaline with black veins, somewhat smoky. Anal triangle 3-celled, cubito-anal space with one crossvein, all triangles uncrossed, nodal index 12–14:14– 10 in FW, 11–11:11– 11 in HW. Pt brown, 3.5 mm, covering 3.5 cells in FW and 3.5–5 in HW.

Anal appendages ( Figs. 5f View FIGURE 5 , 6f View FIGURE 6 , 7f View FIGURE 7 , 8d View FIGURE 8 ). Cerci blackish brown, base brownish yellow, epiproct black. Cerci simple, unbranched, widely diverging in dorsal view and apically tapering to a posteriorly directed point ( Fig. 5f View FIGURE 5 ), in lateral view upper margin only slightly bend downward, apically inflicted posteriorly to form sharp tip, in length cerci approximately 1.2x length of S10 and extending beyond epiproct ( Fig. 6f View FIGURE 6 ). Epiproct deeply bifid, branches simple, diverging slightly more than cerci and triangular ( Figs. 5f View FIGURE 5 , 7f View FIGURE 7 ), rather flat, tapering to a slightly arched inward blunt tip, at two-thirds from base raised to a slight ridge dorsally and between ridge and tip a rounded bowllike depression ( Fig. 8d View FIGURE 8 ). In lateral view equally simple, slightly shorter than cerci, ventral margin first slanting downward, then at two-fifths from base forming a heel and rising again, its apical part somewhat thinning apically. Dorsal margin shallowly concave ( Fig. 6f View FIGURE 6 ). Apex tapering to blunt point, hooked inward and upward to form small dorsal tooth. Posterior margin of epiproct between branches smoothly curved ( Fig. 5f View FIGURE 5 ).

Measurements (in mm). Total length (incl. appendages) 56, HW 37.

Variation in paratype male. Metepisternum with complete yellow lateral stripe, dorsally forming a rectangle, the stripe running down from the posterior half of the rectangle, passing behind the spiracle. S4–6 with complete antero-dorsal half-ring. S10 and cerci all black. 18 Ax and 15 Px in FW, Ax 14 and Px 16 in HW. Pt covering 4.5 cells. HW length 40.5 mm.

Female. Unknown.

Differential diagnosis. Asiagomphus kosterini sp. nov. is a striking species, easily separable from known Asiagomphus species by its distinctive color pattern, in addition to structural aspects. Most Chinese, Korean, and Japanese species have a distinct complete antehumeral stripe in addition to the dorsal stripe, and have longitudinal dorsal stripes on the abdomen. Chao (1990) separates A. motouensis Liu & Chao, 1990 from all other species in his key as the only species that combines a black occiput with an antehumeral spot, but lacks an antehumeral stripe. However, A. motouensis has a completely different thorax pattern from A. kosterini , lacking a continuous black stripe over the interpleural suture and virtually black metepisternum. Structurally its cerci do not obviously extend beyond the epiproct. Two Chinese species, A. hesperus and A. pacatus , have somewhat similar pattern on S8–9, but differ structurally. Asiagomphus hesperus has for instance the apex of the posterior hamulus directed inwards in addition to many differences in the thorax pattern. In A. pacatus the apex of the posterior hamulus is slender and almost horizontally directed anteriorly, again in addition to many differences in color pattern. The Japanese endemic species all have a complete antehumeral stripe and three out of four have a longitudinal pattern on the abdomen. The fourth, A. yayeyamensis , lacks a black stripe over the interpleural suture and has yellow metepisternum, in addition to many other differences. Asiagomphus acco has black abdomen, and different cerci. Asiagomphus reinhardti is easily identified by the protrusion of the posterior margin of S10 and different cerci. Asiagomphus giza is only known from a female, but has longitudinal markings on the abdomen. The western species A. nilgiricus and A. personatus have longitudinal markings on the abdomen ( Fraser 1925) and A. odoneli has differently marked S8–9, without postero-dorsal yellow spot. Asiagomphus auricolor , A. monticola , A. superciliaris and A. xanthenatus have half-rings at the base of abdomen segments, lack lateral markings on S8 or spots on S10, and have different posterior hamulus, directed more inward at the apex ( A. auricolor ), have curled apices ( A. superciliaris ) or directed more horizontally anteriorly ( A. xanthenatus ), different anterior hamulus and different epiproct. Asiagomphus coreanus has complete antehumeral stripe, yellow metepisternum, interrupted black stripe over interpleural suture, and different appendages. Asiagomphus melanopsoides also has complete antehumeral stripe and longitudinal pattern over the dorsum of the abdomen. Asiagomphus gongshanensis was described from a female specimen. Said to resemble A. personatus , its abdomen markings should help to separate it easily. As said under A. auricolor above, the poorly known A. corniger has completely different anal appendages.

Habitat and ecology. Asiagomphus kosterini was found on small, shallow and pebbly streams under forest cover at approximately alt. 1,450 m in Da Lat, and at almost the same altitude in Bidoup – Nui Ba NP, where it inhabited a small and shallow dream with mud and sand substrate under forest cover.

Discussion. The difference in the holotype and paratype in the patterning of the metepisternum, in addition to small differences in the patterning of the abdomen serves as a warning against the use of such characters without support by a mix of other characters, both in patterning and structure. Similar variation is seen in several other species, for instance A. auricolor , A. monticola , A. reinhardti , and A. xanthenatus .