Leptogomphus sii Dow & Stokvis & Ngiam 2017, sp. nov.
Creators: name: Dow, Rory A.
name: Stokvis, Frank
name: Ngiam, Robin W. J.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Gomphidae
Leptogomphus
Leptogomphus sii

description: Leptogomphus sii sp. nov.
(Figs 1, 2, 3, 7, 15, 22, 40, 57, 64, 65, 72, 82, 92, 98, 104, 110, 116, 124, 127, 131)
Leptogomphus cf pasia;— Dow & Ngiam 2012: 15, Fig. 13 (♀, Hose Mountains, Sarawak). Leptogomphus sp.;— Dow et al. 2013a: 11, 14 (♀, Mount Dulit).
Holotype 1 ♂ (SAR 13_14_GOM46: RMNH.5008435), tributary to Sungai Sii opposite camp, Upper Baram, Miri Division, 2.99113N, 114.90581E, 13 vii 2014, leg. R.A. Dow, in RMNH
Paratypes (all Sarawak, Malaysia): 1 ♂ (semi-teneral, reared from larva), Nattarant stream, Gunung Pueh/ Kenyi, Lundu, Kuching Division, ca 745m, 31 vii 2013, leg. R.W.J. Ngiam, to be deposited in ZRC; 1 ♂ (SAR 16_GOM4; teneral), Sungai Bedawak, Nanga Bloh, LEWS, Kapit Division, 1.63798N, 112.22162E, 11 iii 2016, leg. M. Adau & B. Megong, in collection Dow; 1 ♂ (teneral; SAR 09_10_GOM33), Sungai Sebabi, Sebabi Recreational Park, Kapit town area, Kapit Division, 1.94N, 112.908E, 20 x 2009, leg. R.A. Dow, in collection Dow; 1 ♀ (SAR 11_12_GOM2), stream ca 840m, Gunung Kajang area, Hose Mountains, Kapit Division, 2.29578N, 113.69284E (Gunung Kajang area), 9 iv 2011, leg. R.A. Dow, in collection Dow; 1 ♀ (SAR 06_GOM35), Sungai Nuam, foot of Mount Dulit, Miri Division, 3.27418N, 114.31285E, 29 iii 2006, leg. R.A. Dow; in collection Dow; 1 ♀ (SAR 09_10_GOM32, teneral), stream at foot of Gunung Kalulong, Upper Baram, Miri Division, 3.19038N, 114.6968E, 9 x 2009, leg. R.A. Dow, in collection Dow; 1 ♀ (SAR 13_14_GOM44: RMNH.INS.509951), tributary to Sungai Sii upstream from camp, same area, 2.99147N, 114.90256E (Sungai Sii), 15 vii 2014, leg. R.A. Dow, in RMNH; 1 ♂ (SAR 13_14_GOM49, used for Fig. 98), tributary to Sungai Sii downstream from camp, 2.99147N, 114.90256E (Sungai Sii), 17 vii 2014, leg. R.W.J. Ngiam, to be deposited in ZRC; 1 ♂ (SAR 06_GOM40, teneral), Sungai Lansat, GMNP, Miri Division, 4.006N, 114.82E (Long (mouth of the) Lansat), 8 ii 2006, leg. R.A. Dow, in collection Dow.
Etymology. Sii, a noun in apposition. Named for the type locality, Sungai Sii in Sarawak’s upper Baram area.
Diagnosis. The male is easily distinguished from those of all other Leptogomphus known from Borneo except L. pasia by the multiple breaks in the pale marking on the metepisternum. It can easily be separated from L. pasia by the shorter antehumeral stripe and the lack of a basal spur on the cerci. The female can be separated from those of L. schieli and L. williamsoni (and L. sp. cf williamsoni) by the form of the dorsal markings on the synthorax and from those of all other species except L. pasia by the vulvar scale reaching onto the sternum of S10 (shorter in the other species), and from L. pasia by its shorter vulvar scale (reaching the apex of the sternum of S 10 in L. pasia) and the shape of the apices of the vulvar scale (compare Figs 121 and 124).
Description of holotype male. Head (Figs 7, 15). Labium mostly black, basal parts paler, grey patches on inner side palps. Labrum black with pair of small, broadly separated, pale basal marks. Mandible bases pale, genae pale adjacent to mandible bases, rest black. Clypeus black. Ante- and postfrons not very sharply divided, black, pale transverse stripe on postfrons, broadly divided centrally (Fig. 15). Vertex and occiput black. Pair of transverse tubercles, narrowly separated centrally, behind lateral ocelli; ocelli orange, vertex smooth behind tubercles. Free margin of occipital plate gently concave, raised to form low ridge with low central mound extending back onto plate.
Thorax. Prothorax mostly black and dark brown, dull, indistinct paler markings laterally on anterior carina of anterior pronotal lobe, yellow lateral mark, tiny, faint, dorsal spot and apical central mark, divided centrally, on middle pronotal lobe, tiny longitudinal brown streak centrally on posterior pronotal lobe. Synthorax dark brown to black with pale yellow-green markings as follows (Figs 57, 64): short, narrow, mesothoracic collar, broadly divided at middorsal carina, joined to narrow dorsal thoracic stripes that extend beyond level of apex of antealar crest. Antehumeral stripe below dorsal thoracic stripe, tapering from near antealar carina to ca two-thirds of mesepisternum length. Stripe running most of length of mesepimeron. Metepisternum with stripe running from metakatepisternum broken in four places so appearing as series of pale patches (Fig. 64; more clearly visible in the teneral male shown in Fig. 65). Broad stripe occupying most of metepimeron, dark below. Mesokatepisternum, metakatepisternum dark with large pale marks. Metaposternum pale with dark lateral streaks, dark subrectangular mark adjacent to S1. Legs (left anterior leg removed for DNA extraction, left middle leg missing below coxae, right anterior leg detached) robust and relatively short. Coxae mottled pale and black, rest black. Wings: sectors of arculus separated at origin with 5 (right) or 4 (left) cross veins up to and at first bifurcation of superior sector in Fw, 3 in Hw. Discoidal field with 2 rows of cells from origin, transitioning to three rows before level of nodus in both wings. 15 (right) or 13 (left) Ax in Fw, 9 in Hw, 12 Px in Fw, 10 (right) or 11 (left) in Hw; incomplete basal Ax absent in Fw. Pt brown, covering ca 4 underlying cells in Fw, ca 4.5 to 5 in Hw.
Abdomen. Slender after base of S3, expanding moderately from base of S7, maximum width and height reached apical part of S8, then almost constant. Dorsum of S10 with pair of prominent ca conical protuberances basally (Fig. 110), bearing many small tubercles on posterior faces. Black with few pale markings as follows: S1 mostly pale laterally, obscurely dull dark brown dorsally. S2 short lateral stripe running from base below and including part of auricle, well separated from another lateral mark placed posteriorly, narrow yellowish middorsal stripe. Remaining segments black laterally, S3–7 with very thin, very faint middorsal line barely apparent. Cerci (Figs 104, 110) black, broad at base in lateral view (Fig. 110), tapering gradually almost for most of their length, turned sharply up to sharp apex, teeth present along much of lower margin. Short, rounded dorsal spur present at the extreme base of the cercus, clearly visible in lateral view. In dorsal view (Fig. 104) relatively slender, tapering evenly to sharp apex. Epiproct (Figs 104, 116) black, slightly shorter than cerci, deeply divided with arms broadly separated, space between trapezoidal, arms gently divergent, tapering to apex, apex rounded in appearance in dorsal and ventral views, outer margins gently convex, apices rounded. In lateral view (Fig. 110) slender, curved gently down then up along lower margin, almost straight over much of upper margin. Accessory genitalia as shown in Figures 92, 98 (Fig. 98 shows a paratype), anterior hamule small, directed downwards and inwards, tapering to sharp tip, hooked to rear in apical ca one-half. Posterior hamule very long, more than two and a half times the height of posterior hamule, directed postero-ventrally, anterior margin directed almost straight down to ca one-third length, then postero-ventrally at ca 45 degrees to shortly below apex, apex directed downwards and slightly outwards. Posterior margin more gently and evenly curved from base to apex. Vesical low, simple. Penis examined in a paratype (see below). Penis vesicle low, simple.
Measurements (mm). Hw 28, abdomen excluding anal appendages 35.5, cerci ca 0.9.
Penis. Figure 98 shows that of SAR13_14_GOM49: penultimate segment extended to rear of join with terminal segment, bifurcated in this part, in lateral view with short sharp apices. Terminal segment extending beyond penultimate segment, dorsal margin almost straight in lateral view, apically short ventrally cornua, a short, ventrally directed flap just before these.
Description of female. Based on SAR13_14_GOM44. As male excepted as noted. Head (Figs 22, 40). Tubercles in same position of male, but narrow, not extending past inner margins of lateral ocelli; pits behind lateral ocelli.
Thorax (Figs 72, 82). Lateral dark streaks on metaposternum faint and small. Right anterior leg missing, right posterior leg removed below coxa for DNA extraction. Wings: sectors of arculus separated at origin with 5 (left) or 4 (right) cross veins up to and at first bifurcation of superior sector in Fw. 15 (right) or 16 (left) Ax in Fw, 11 (right) or 10 (left) in Hw, 12 (right) or 11 (left) Px in Fw, 11 in Hw; incomplete basal Ax present in all wings.
Abdomen. Gradually tapering from base to S8, contracting on S9 before expanding slightly apically (giving pinched appearance). Black with few pale markings as follows: S1 mostly pale. S2 lateral stripe running from base to apex including small rounded auricle, narrow yellowish middorsal stripe. S3 with short basal stripe. Cerci black, tapering to sharp points, ca one and a half times as long as S10. Vulvar scale (Figs 124, 127) longer than S9, extending well onto basal half of S10, divided at ca half length, arms running ca parallel, outer edge almost straight to apex, inner edges straight until over S10, then curved out to apex. Sternum of S8 with slight swelling in the same position as the distinct tubercle seen in L. coomansi females.
Measurements (mm). Hw 30.5, abdomen excluding anal appendages 35.
Variation in paratypes. There is little variation in the type series. The labial palps are sometimes more extensively or entirely pale even in mature males. The incomplete basal Ax are normally present in all wings, but are lacking in both Hw of one female. One male has tiny basal lateral marks on S3. Teneral specimens are, of course, generally paler.
Measurements (mm). Males: Hw 28–28.5, abdomen excluding anal appendages 36, 12–19 Ax in Fw, 9–13 in Hw, 7–14 Px in Fw, 10–14 Px in Hw. Females: Hw 30–30.5, abdomen excluding anal appendages 34–36, 16–18 Ax in Fw, 11–13 in Hw, 12–13 Px in Fw, 11–13 Px in Hw.
Remarks. The female is associated with the male based on similarity of markings and DNA, with 98.8% identical sites in COI and 99.9% identical sites in ITS between the male and the female analysed.
This species is closely related to L. pasia, from which it differs in markings, structure of the male anal appendages and penis and in the shape and length of the vulvar scale. This close relationship is also evident in the molecular analyses: the two are sister species in the gene trees (Figs 1, 2) and phylogeny (Fig. 3) presented. Leptogomphus sii is widely distributed in Sarawak, but known from relatively few locations (Fig. 127). It occurs at streams in mixed dipterocarp forest in hilly and mountainous terrain.
description: Published as part of Dow, Rory A., Stokvis, Frank & Ngiam, Robin W. J., 2017, Revision of the Genus Leptogomphus Selys in Borneo, including gene trees and a two marker molecular phylogeny (Odonata: Anisoptera: Gomphidae), pp. 201-257 in Zootaxa 4358 (2) on pages 227-230, DOI: 10.11646/zootaxa.4358.2.1, http://zenodo.org/record/1067996