Leptogomphus coomansi Laidlaw 1936
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 coomansi

description: Leptogomphus coomansi Laidlaw, 1936
(Figs 1, 2, 3, 4, 10, 11, 18, 19, 28, 29, 36, 37, 46, 52, 53, 60, 68, 69, 78, 79, 88, 94, 100, 106, 112, 118, 120, 126, 133, 134)
Leptogomphus coomansi Laidlaw 1936: 267 –269, Fig. 1 (original description, holotype ♂, allotype ♀, Singkawang area);— Lieftinck 1948: 245 –247, Plate 8, Fig. 10 (types re-examined);— Lieftinck 1954: 81;— Lieftinck 1971: 81 (note on holotype and “first described” female);—? Tsuda & Kitagawa 1989: 38 (♀, Poring, Sabah);—van Tol 1990: 98, 99, 101, 104, Figs 18, 26, 27, Table 1, 2 (key);—van Tol 1992: 72;—Thompson & van Tol 1993: 70 (Belait, Brunei);— Orr 2001: 198 –199 (Brunei);— Orr 2003: 40, 96–97, Figs 141, 142, plate 12c (discussed);— Dow & Reels 2010: 15 (Kubah NP, Sarawak);— Dolný et al. 2011: 73, 85 (Sungai Wain, Kailmantan Timur);— Bárta & Dolný 2013: 99 (images of female);— Dow & Reels 2013: 20, Fig. 16 (Ranchan Recreational Park, Sarawak);— Dow et al. 2013b: 19 (Kubah NP, Sarawak);— Dow & Ngiam 2015: 24 (Sungai Sii, upper Baram, Sarawak);— Dow et al. 2015a: 10, 27 (Batang Ai NP and locations in Kapit Division, Sarawak);— Steinhoff 2015: 8, Fig. 5b (GMNP, larva reared);—Dow 2016: 8 (Samunsam Wildlife Sanctuary, Sarawak).
Leptogomphus cf coomansi Laidlaw;— Cleary et al. 2004: 445 (Kalimantan Timur).
Leptogomphus mariae Lieftinck 1948: 249 –251, Plate 8, Fig. 10 (original description ♀, Kutai);— Lieftinck 1954: 82;— Lieftinck 1971: 99 –100 (note on holotype);—van Tol 1990: 99, 104, Table 1, 2 (female in key);—van Tol 1992: 148;— Orr 2001: 199 (females, Brunei);— Orr 2003: 40, 96 (discussed). Syn. Nov.
Leptogomphus spec. A;— Steinhoff 2015: 8 (female reared from larva, GMNP).
Material studied. Type material. Holotype 1 ♂ (JvT number 3460), Pakmiongtheo-Pandjoa, Singkawang, Kalimantan Barat, Kalimantan, Indonesia, 0.75725N, 109.1381E (coordinates for Montrado which is supposed to be close to Pandjoa), 3 iv 1932, leg. L.C. de Ruiter, in RMNH. Other type material. 1 ♀, holotype of L. mariae (JvT number 3463), Daguanan, Sangkulirang District, Kalimantan Timur, Indonesia, 0.977N, 117.9803E (coordinates for Sangkulirang) vi 1937, leg. M.E. Walsh, in RMNH; 1 ♀, allotype of L. coomansi, Sungai Bagak, Singkawang, 0.841492N, 109.056146E (coordinates for Gunung Poteng, Sungai Bagak assumed near to this), 10 vi 1933, leg. L.C. de Ruiter, in RMNH.
Other material. Kalimantan Barat, Indonesia: 1 ♂, same data as holotype, in RMNH.
Kalimantan Timur, Indonesia (in RMNH unless explicitly otherwise noted): 3 ♀♀, Tabang, Kali Bengin, 0.5667N, 116.0333E (approximate coordinates for Tabang), 125m, 1 ix 1956, leg. A.M.R. Wegner; 1 ♀, same data except 2 ix 1956; 1 ♂, 1 ♀, same data except 3 ix 1956; 1 ♀, same data except 4 ix 1956; 3 ♀♀, same data except 8 ix 1956; 1 ♂, same data except 10 ix 1956; 1 ♀, same data except 18 ix 1956; 1 ♀, same data except 21 ix 1956; 1 ♂, same data except 26 ix 1956; 1 ♀, same data except 28 ix 1956; 1 ♀, same data except 29 ix 1956; 1 ♀, same data except 30 ix 1956; 2 ♀♀, same data except 2 x 1956; 1 ♀, same data except 5 x 1956; 1 ♀, same data except 6 x 1956; 1 ♂, 2 ♀♀, same data except 7 x 1956; 1 ♀, same location and collector, 6 ix 1956, in BMNH; 1 ♂, same data except 7 x 1956, in BMNH; 1 ♂, same data except 9 x 1956; 1 ♂, same data except 17 x 1956; 1 ♂, same data except 24 x 1956; 1 ♀, same data except 27 x 1956.
Kalimantan Selatan, Indonesia: 1 ♀, Sungai Kalaan, 3 km SE of Belangian village, Riam Kanan Lake, Aranio District, Banjarbaru, - 3.5059N, 115.0923E (Riam Kanan), 100m, 15 xi 1996, leg. M. Bedjanic, in coll. Dow.
Sarawak, Malaysia: 1 ♂, Sungai Assam, Samunsam Wildlife Sanctuary, Kuching Division, 1.92705N, 109.60133E, 18 viii 2015, leg. R.A. Dow, in collection Dow; 1 ♀, last stream on Summit Trail, Gunung Gading, Gunung Gading NP, Kuching Division, 1.70242N, 109.83627E (Gunung Gading), 3 viii 2016, leg. R.A. Dow, in collection Dow; 1 ♀, Tebang, Kuching Division, 1.11905N, 110.22793E (Gunung Penrissen, Tebang supposed to be somewhere on this mountain), 7 ix 1958, leg. T.C. Maa, in RMNH; 1 ♀, same data except 8 ix 1958; 1 ♂, 1 ♀, streams on Belian trail, Kubah NP, Kuching Division, 1.617N, 110.192E, 15 ix 2008, leg. R.A. Dow, in collection Dow; 1 ♀ (SAR11_12_GOM48, RMNH.INS.506897, used for description and illustrations), perched on road up Gunung Serapi, same NP, 1.613N, 110.197E (Kubah NP), 3 ix 2012, leg. R.A. Dow, in RMNH; 1 ♂ (SAR09_10_GOM4, RMNH.INS.503526, used for description below and illustrations), ponded section of small stream very near confluence with Sungai Rayu, Matang Wildlife Centre, Kuching Division, 1.609N, 110.161E (Matang Wildlife Centre), 9 ix 2009, leg. R.A. Dow, in RMNH; 1 ♂ (RMNH.INS.506264), same location, 1 iv 2012, leg. R.A. Dow, in RMNH; 1 ♀, on road to Hindu Temple on Mount Matang, Matang Range, Kuching Division, 1.59632N, 110.20949E (Mount Matang), 5 vii 2015, leg. R.A. Dow, in collection Dow; 1 ♀, stream at Ranchan Recreational Park, Serian, Serian Division, 1.14N, 110.581E, 14 ii 2008, leg. G.T. Reels, in collection Dow; 1 ♀, Sungai Kepayang, Ulu Sebuyau, Samarahan Division, 1.27712N, 110.94812E, 10 vii 2015, leg. L. Southwell, in collection Dow; 1 ♂ (SAR07_8_GOM18, used in Fig. 94), tributary to Sungai Bebiong Mit, Batang Ai NP, Sri Aman Division, 1.202N, 112.058E (approximate coordinates in Batang Ai NP), 5 xii 2007, leg. R.A. Dow, in collection Dow; 1 ♂, same location and date, leg. G.T. Reels, in collection Dow; 1 ♂, Sungai Segak Mit, Ulu Mujok area, inside LEWS, Sarikei Division, 1.70636N, 112.08934E, 30 vii 2015, leg. R.A. Dow, in collection Dow; 2 ♂♂, Sungai Segak Besai, same area, 1.68253N, 112.15868E, 14 viii 2016, leg. R.A. Dow, in collection Dow; 1 ♀ (teneral), Sungai Mujok, same area, 1.6825N, 112.15791E (Sungai Mujok at LEWS boundary), 15 viii 2016, leg. L. Southwell, in collection Dow; 1 ♂ (teneral), Sungai Selabi, same area, 1.6929N, 112.16291E, 16 viii 2016, leg. R.A. Dow, in collection Dow; 1 ♀, Sungai Tekalit, same area, 1.67589N, 112.17488E, 17 viii 2016, leg. B. Megong & N. Mengiring, in collection Dow; 1 ♀, Sungai Sengkadan, same area, 1.6817N, 112.15192E, 17 viii 2016, leg. R.W.J. Ngiam, to be deposited in ZRC; 1 ♂ (teneral), same location, 18 viii 2016, leg. R.A. Dow, in collection Dow; 1 ♂, Sungai Temurok, same area but outside LEWS boundary, 1.69165N, 112.12991E, 4 viii 2015, leg. N. Masil, in collection Dow; 1 ♂, Sungai Lingga, same area, 1.70369N, 112.11807E, 5 viii 2015, leg. R.A. Dow, in collection Dow; 1 ♂, Sungai Mujok, same area, 1.71235N, 112.08381E (coordinates by Sungai Mujok), 17 viii 2016 (after 6 pm), leg. R.A. Dow, in collection Dow; 1 ♂, Sungai Sbong, Kapit Town area, Kapit Division, 2.009N, 113.118E, 11 ii 2008, leg. G,T. Reels, in collection Dow; 1 ♂ (RMNH.INS.509952), stream in disturbed forest, foot of Hose Mountains, Tunoh district, Kapit Division, 2.0698N, 113.6474E, 16 v 2010, leg. G.T. Reels, in RMNH; 1 ♀ (RMNH.INS.509950), tributary to Sungai Sii, Upper Baram, Miri Division, 2.99113N, 114.90581E (Sungai Sii), 16 vii 2014, leg. R.A. Dow, in RMNH; 1 ♂, stream on Oil Well trail, Lambir Hills NP, Miri Division, 4.2004N, 114.0303E, 22 iv 2011, leg. R.A. Dow, in collection Dow; 1 ♂ (RMNH.INS.506807), tributary to Sungai Liku, extension area to same NP, 4.23313N, 114.06127E, 16 vii 2012, leg. L. Southwell, in RMNH; 1 ♂ (teneral), 1 ♀, Sungai Melinau, GMNP, Miri Division, 4.0559N, 114.8257E, 16 ii 2006, leg. J. Simun, in collection Dow; 1 ♂ (teneral), Bat Observatory Stream, same NP, 4.024N, 114.819E, 28 xii 2007, leg. R.A. Dow, in collection Dow; 1 ♂ (teneral), same location, 30 xii 2007; leg. R.A. Dow, in collection Dow; 1 ♂, same location, 21 iv 2014 (6:15 pm), leg. P.O.M. Steinhoff, in collection Steinhoff; 5 ♂♂, same location, 22 v 2014 (6 pm and after), leg. P.O.M. Steinhoff, in collection Steinhoff; 1 ♂, Sungai Paku, same area, 4.048N, 114.836E (coordinates on Sungai Paku), 21 iv 2014 (6:15 pm), leg. P.O.M. Steinhoff, in collection Steinhoff; 1 ♂, second stream on old trail to Sarawak Chamber, 4.059N, 114.861E, 13 i 2008, leg. R.A. Dow, in collection Dow; 1 ♂, open area on summit trail near Camp 1, same NP, 13 ix 2008, leg. R.A. Dow, in collection Dow; 1 ♂, Lubang Cina, Headhunters Trail, same NP, Limbang Division, 4.198N, 114.895E (approximate coordinates on Headhunters Trail), 11 ii 2006, leg. R.A. Dow, in collection Dow; 1 ♂, same location, 14 ii 2006, leg. R.A. Dow, in collection Dow; 1 ♂, Mentawei boundary trail, same national park and Division, 4.239N, 114.877E (approximate coordinates), 13 ii 2006, leg. J. Simun, in collection Dow.
Brunei: 1 ♀, Sungai Ingei, Belait district, 4.1535N, 114.7201E (Sungai Ingei), 30 ix 1992, leg. D. Thompson, in RMNH; 1 ♀, track in freshwater swamp forest, along Ingei river, surroundings Ingei base camp, same area, 4.1535N, 114.7201E (Sungai Ingei), same date and collector, in BMNH; 1 ♂, same location and collector, 2 x 1992, in RMNH; 1 ♂ (RMNH.5008295), camp at Sungai Ingei, Belait district, 4.1535N, 114.7201E (Sungai Ingei), 24 ii 2014, leg. R.A. Dow; 1 ♂ (RMNH.5008363), same location, 10 iii 2014, leg. R.A. Dow, in RMNH; 5 ♂♂ (including RMNH.INS.500716), Sungai Lumut, Belait district, 4.6167N, 114.5167E (Sungai Lumut), 17 xi 2004, leg. V.J. Kalkman et al., in RMNH.
Description of male (based on SAR09_10_GOM4, RMNH.INS.503526 Kubah NP). Head (Figs 4, 10). Median lobe labium black, lateral lobes pale, hooks black. Labrum black with pale central transverse basal mark, not quite divided centrally. Mandible bases pale, genae brownish adjacent to mandible bases, rest black. Anteclypeus black. Postclypeus mostly black with pale basal transverse mark occupying most of width, in centre extending almost to anteclypeus. Ante- and postfrons not sharply divided, whole mostly greenish, very narrowly divided by black centrally, black to rear postfrons (Fig. 4). Vertex and occiput black. Pair of ridge-like transverse tubercles behind lateral ocelli, narrowly divided centrally and extending almost to compound eye margins, remainder of vertex smooth, ocelli orange. Free margin of occipital plate raised to form narrow ridge, narrowly extended forward centrally.
Thorax. Prothorax dark brown, most of anterior pronotal lobe pale yellow, pale yellow transverse marking to rear of middle lobe, deepest laterally, and centrally where narrowly divided, a small isolated yellow spot centrally on dorsum. Posterior pronotal lobe with tiny central yellow spot. Propleuron mottled brow and black. Synthorax dark brown with pale yellow-green markings as follows (Figs 52, 60): short, narrow mesothoracic collar, broadly divided at middorsal carina, joined to narrow dorsal thoracic stripes that extend beyond level of apex of antealar crest, terminating just short of antealar carina, almost parallel on their inner margins. Small spot below dorsal thoracic stripe on mesepisternum, near antealar carina. Stripe running most of length of mesepimeron. Metepisternum with irregular stripe running from metakatepisternum, surrounding spiracle, narrowly separated from subcircular spot at antealar carina (Fig. 60). A broad stripe occupying most of metepimeron. Mesokatepisternum dark brown and pale, metakatepisternum mostly pale. Venter pale. Legs (posterior pair removed for DNA extraction) robust and relatively short. Anterior and middle pairs with coxae mottled pale and dark grey, remainder mostly black. Wings: sectors of arculus separated at origin with 6 (right) or 5 (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. 17 (left) or 18 (right) Ax in Fw, 12 (left) or 13 (right) in Hw, 12 Px in all wings. Pt brown, covering ca 5 underlying cells.
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. 106), bearing many small tubercles on posterior faces. Dark brown to black with pale markings as follows: S1 mostly pale laterally, pale and dark dorsally. S2 pale lateral stripe running from base below and including auricle, except free margin of auricle, another pale lateral mark placed posteriorly, narrow yellowish middorsal stripe. S3 with small basal lateral pale marking, S3–6 with very narrow and rather irregular middorsal yellow line. Cerci (Figs 100, 106) broad at base in lateral view (Fig. 106), tapering to sharp tip, along upper margin sloping down from base to just before mid-length, then more gently to apex, along lower margin sloping down from base to ca one-third length, then gently up to apex, small teeth present along much of lower margin. In dorsal view (Fig. 100) relatively slender, outer margin curving slightly out from base, then running gently inward until just before apex, where turned slightly outward. Black, brown at base laterally, this more extensive dorsally. Epiproct (Figs 100, 112) black, and dark brown, just shorter than cerci, deeply divided in a “U” shape, outer margins gently convex, apices rounded. In lateral view (Fig. 106) curved gently down then up. Accessory genitalia as shown in Figures 88, 94, anterior hamule moderate sized, ca three-quarters height of posterior hamule, tapering toward rounded apex, hooked to rear in apical ca one-third. Posterior hamule large, ca parallel sided over much of length and directed postero-ventrally, curving gently toward sharp tip along posterior margin, abruptly hooked back to tip along front anterior margin, apex pointed slightly out. Penis missing (see below). Penis vesicle low, simple.
Measurements (mm). Hw 28, abdomen excluding anal appendages 35.5, cerci ca 1.
Description of female (based on SAR11_12_GOM48, RMNH.INS.506897 Kubah National Park). Head (Figs 18, 28, 36, 46). Pale marks yellow. Labrum pale central transverse basal mark divided centrally. Genae yellowish adjacent to mandible bases. Postclypeus with additional pair of tiny yellow marks widely spaced near anteclypeus, that on the right very faint. Marking on post frons not divided centrally. On each side behind the ridgelike transverse tubercles and adjacent to the compound eyes is a distinctive pit. Occipital plate bearing pair of occipital horns placed near eye margins, centrally with shallow notch to rear, slightly raised immediately to each side of this.
Thorax (Figs 68, 78). No small isolated yellow spot centrally on dorsum of pronotal middle lobe. Posterior pronotal lobe almost entirely yellow. Stripe running most of length of mesepimeron partially and narrowly intruded by brown on left side (Fig. 78). Mesokatepisternum dark brown with yellow triangular marking based by coxa. Venter pale. Legs: right middle removed for DNA extraction, left anterior detached below coxa, left middle detached below trochanter. A small, obscure pale area in the upper interior flexor surface of the anterior femur. Wings: 17 (right) or 19 (left) Ax in Fw, 12 (left) or (13) in Hw, 12 Px in all wings except left Fw, where 13. Pt brown, covering ca 4-5 underlying cells.
Abdomen. Only expanding slightly from base of S7. S1 large lateral yellow mark, separated from broad dorsal mark. S2 pale lateral stripe running from base, including small rounded auricle, to posterior carina, broad dorsal stripe, widest at base. Middorsal line on S3–6 better developed than in male, but still narrow. Cerci conical, longer than S10, tapering to sharp tip, tips slightly divaricate, a short but prominent, rounded, epiproct in between. Vulvar scale (as in Fig. 120) ca two thirds length of S9, divided at between one third and one half of its length from base. The sternite of S8, is strongly depressed for a short distance at around two-thirds length, immediately after this there is a prominent tubercle (as in Fig. 118).
Measurements (mm). Hw 32, abdomen excluding anal appendages 36.5.
Variation. Leptogomphus mariae is discussed separately below. There is considerable variation in the extent of pale markings on the labrum and clypeus. In a number of males, mostly from GMNP in Sarawak, the clypeus is entirely black, but various intermediate conditions between an entirely black clypeus and the condition seen in the male described here (and in the holotype) occur as well. No female examined, except the holotype of L. mariae (see below) and a teneral female from Sungai Ingei in collection Orr (A.G. Orr personal communication) has an entirely black clypeus, but a few others have only small pale marks there. Nearly all specimens examined (both sexes) have either most of the antefrons pale, or an extensive intrusion of pale colour from postfrons onto antefrons (not just narrowly along the upper part). However three males from Mulu have no pale colour on the antefrons. The occipital horns, when present, vary in orientation and length; they are entirely absent in nine of the females examined (six from Kalimantan, three from Sarawak) and only present on the right hand side in another three from Kalimantan. The pits behind the tubercles are present in all specimens considered to belong to L. coomansi.
There is variation in the exact width of the mesothoracic collar and the middorsal thoracic stripes; in one male from Lambir Hills the middorsal thoracic stripes are only connected to the mesothoracic collar on their inner side. In some individuals of both sexes there is a faint and very narrow section of antehumeral stripe present (never complete and never joined with the spot on the mesepisternum) around mid-length on the mesepisternum. There is variation in the exact shape of the stripe on the metepisternum and occasionally it is joined to the spot near the antealar carina on one or both sides of the synthorax. Small variations occur in wing venation and in the markings of the abdomen. The wing membrane varies between entirely hyaline to deeply brown tinted over much of the wing.
In males, there is some variation in how produced and how upturned the tip of the cercus is, but the main variation is in the curvature of the arms of the epiproct in lateral view; in some individuals they appear almost straight along the upper margin in its central part, in others the upper margin is strongly curved, almost semicircular. In females there is some variation in the exact shapes of the apices of the vulvar scale and its exact length. The peculiar tubercle on the sternite of S8 is present on all examined females where the condition of the specimen allows examination of this part, except that this character was only noticed after most older specimens from Kalimantan, Sabah and Brunei in RMNH and BMNH were examined by the first author, so it cannot be confirmed that it is present in these.
Considerable variation in size occurs in this species. Specimens from Sungai Ingei in Brunei are the smallest, but aside from this no clear geographical pattern is apparent to this variation.
Penis. Unfortunately the penis of the specimen used in the description above was lost during extraction. The penis has been examined in a number of other specimens (e.g. Fig. 94 which shows that of SAR07_8_GOM18). The penultimate segment is extended to rear beyond the join with the terminal segment, and is bifurcated in this part, apices broadly triangular in lateral view, sometimes bent outwards so looking almost square ended in lateral view. The terminal segment is large at base, with a slightly constricted section before the apical part, giving the upper margin a bi-lobed appearance in lateral view. The apical part of the terminal segment bears two short cornua, just before these is a short ventrally directed flap, this can appear like a spine in lateral view. There is some variation in the depth of the constriction of the terminal segment, it is frequently shallower than in the individual illustrated.
Leptogomphus mariae. Lieftinck (1948) described L. mariae based on a single female, noting that it is “probably most closely related to coomansi ”, but stating that it differs from L. coomansi (of which only the holotype male and one female were available at the time) “in its superior size, the structural features of the head, the much denser venation and longer pterostigma, and in details of colouration.” Examination of the holotype of L. mariae has revealed that here are a number of inaccuracies in Lieftinck’s description of L. mariae.
Lieftinck mentions a “small greenish spot placed upon the middle of the occipital plate” but no such spot is evident (Fig. 19); there is a slightly lighter region (dark brown rather than black) in this position but it is difficult to imagine that this ever appeared greenish.
On the pits behind the tubercles on the vertex, Lieftinck writes “Just behind each of these protuberances are two minute smooth concavities, one placed in front of the other.” In fact only a single pit is evident behind each tubercle (Fig. 29), falling well within the range of variation seen in L. coomansi females.
Lieftinck states “Occipital plate with two distinct, divergent, roundish lateral ridges which are widest basally, originating from a point a little distant from the eye margin near the rounded occipital margin, but soon curving cephalad and laterad, stopping short a short distance ahead along the mesial border of the eye, sloping gently down without forming a projecting spine or protuberance”. These “ridges” are actually horns (Fig. 29), as seen in L. coomansi (Fig. 28), but very strongly bent forward; possibly the position of the horns is not natural but the result of pressure applied to the head of the specimen, the top of the basal parts looks somewhat flattened and squashed.
Apart from the extreme angle to the occipital ridge of these horns, they fall within the variation in shape and size seen in L. coomansi.
Lieftinck states that “Prothorax entirely green above, only the sides of the median portion somewhat obscured.” A casual glance at the specimen conveys the impression that Lieftinck’s statement is more-or-less accurate, but a detailed examination reveals more extensive dark areas anterio-centrally on the middle pronotal lobe and in fact the colouration is much like that of the other Bornean species.
For the synthorax, Lieftinck refers the reader to his plate 8, where that of the female of L. coomansi is also illustrated. Differences in the dorsal markings in L. mariae fall within the variation seen in L. coomansi. Lieftinck’s illustration of the right hand side of the synthorax shows a significant difference in the pale marking on the metepisternum from that illustrated for L. coomansi in the same plate; the illustration of L. mariae is accurate but the marking on the left hand side (shown in Fig. 79 here) is typical for L. coomansi; and the marking of the right hand side falls within the variation seen in the L. coomansi females examined for this study.
Differences in density of wing venation and the length of the pterostigma between L. coomansi and L. mariae stated by Lieftinck are merely the result of the very few specimens examined; L. mariae actually falls within the variation seen in L. coomansi in these characters (at the upper end of pterostigma length). Although not explicitly mentioned, Lieftinck’s illustrations (his Fig. 10 on page 250) seem to show some differences in the vulvar scale of L. mariae compared to L. coomansi, but again examination of more material has shown that the vulvar scale of L. mariae falls within the variation in L. coomansi. The tubercle on the sternite of S8 of L. coomansi females is also present in the holotype of L. mariae.
Leptogomphus mariae is slightly larger than any female of L. coomansi examined in this study, with abdomen and Hw each ca 1mm longer than in the largest L. coomansi specimens (note that Lieftinck gives the Hw length of L. mariae as 35mm but the first author of this paper measured it as 34mm). The entirely black clypeus is unusual, but does occur in some L. coomansi males and one female in collection Orr; this female is at the lower end of the size range of L. coomansi (A.G. Orr personal communication), in contrast to the L. mariae holotype. The L. mariae holotype has a reduced pale marking on the frons compared with typical L. coomansi but there is sufficient variation in this character in L. coomansi to be sure that it is not a reliable diagnostic feature.
On balance there seems insufficient reason to keep L. mariae separate from L. coomansi at this time. The only characters in which it falls outside of the variation seen in typical L. coomansi females are the entirely black clypeus (Fig. 37) and slightly greater size. However some female L. coomansi have very reduced pale markings on the clypeus (entirely black in one, as mentioned above), and some males also have an entirely black clypeus; the size difference alone is not great enough to justify the separation of L. mariae from L. coomansi. Therefore we consider L. mariae to be a junior synonym of L. coomansi.
Measurements (mm). Males: Hw 27.5–32, abdomen excluding anal appendages 32–38.5, 15–19 Ax in Fw, 11– 14 Ax in Hw, 10–14 Px in Fw, 9–13 Px in Hw. Females: Typical L. coomansi: Hw 30–33, abdomen excluding anal appendages 34.5–39, 14–19 Ax in Fw, 11–14 Ax in Hw, 10–14 Px in Fw, 9–13 Px in Hw; holotype of L. mariae: Hw 34, abdomen excluding anal appendages ca 40.
Remarks. The COI gene tree (Fig. 1) shows L. coomansi divided into two clades. One clade consists of specimens from Belait district in Brunei and Lambir Hills in Sarawak (not far from Brunei), and also including L. sp. cf coomansi. The other clade consists of specimens from the upper Baram in Sarawak’s Miri Division, the Hose Mountains in Kapit Division and Kubah National Park in Kuching Division; these locations are well spread across Sarawak. However the ITS gene tree (Fig. 2) tells a somewhat different story, with L. sp. cf coomansi separated, albeit weakly, from L. coomansi, and little separation between the L. coomansi samples. The combined analyses (Fig. 3) retains the separation of L. sp. cf coomansi as the sister of L. coomansi seen in the ITS gene tree, but relationships within L. coomansi are dominated by the COI so that the same two clades seen in Fig. 1 appear in Fig. 3. No consistent morphological difference has been found between the two clades in L. coomansi seen in Figures 1, 3 and in the absence of further evidence we do not believe that they represent separate, cryptic species, and are merely the result of variation in the COI marker within one biological species.
As noted above, the pits behind the tubercles are present in all females examined and appear to offer a more reliable diagnostic character than the occipital horns, which are variably present. The peculiar tubercle on the sternum of S8 also appears to offer a diagnostic character for the female; swellings are present in this position in some of the other named species, but are not as well developed as in L. coomansi.
Leptogomphus coomansi occurs at forest streams in the lowlands of Borneo, and has been recorded from a wide range of stream sizes, from very small closed canopy streams to broad open canopy ones. It is widely distributed in Brunei, Kalimantan and Sarawak (Fig. 126). The only record of L. coomansi from Sabah that we are aware of is that of a female from Poring in Tsuda & Kitagawa (1989) without any further details apart from the date of collection. We consider this record as unconfirmed, at least until more material of this species from Sabah becomes available. However, the species is likely to occur in Sabah.
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 208-213, DOI: 10.11646/zootaxa.4358.2.1, http://zenodo.org/record/1067996