Leptogomphus, Dow & Stokvis & Ngiam, 2017

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), Zootaxa 4358 (2), pp. 201-257 : 241-243

Leptogomphus species

( Figs 1 , 2 , 3 , 23 , 31 , 41 , 49 , 73 , 83 , 128 )

Material studied. 1 ♀ ( SAR 11_12_GOM33: RMNH.INS.506307), tributary of Pa’Lungan, ca 1,300m, Pulong Tau National Park, Miri Division, Sarawak, Malaysia, 3.84912N, 115.51678E, 9 iv 2012, leg. Fernado, in RMNH.

Description. Head ( Figs 23 , 31 , 41 , 49 ). Median lobe labium brownish, lateral lobes and hooks pale. Labrum, mandible bases, brown. Clypeus brown, postclypeus with pair of widely spaced, small, poorly defined yellow marks. Frons brown, postfrons with pale transverse stripe, just extending onto upper part antefrons ( Fig. 41 ). Vertex and occiput brown. Pair tubercles behind lateral ocelli, outer parts of these produced into a pair of moderately long, robust, rounded horns (referred to as tubercle horns in Fig. 31 ), rest of vertex smooth; ocelli yellowish. Tubular ridge running along hind margin of each compound eye onto occipital plate where it terminates as very robust, rounded projection (referred to as occipital tubes in Figs 31 , 49 ), occipital plate markedly raised in between these.

Thorax. Prothorax mostly brown, anterior pronotal lobe with anterior carina pale, middle pronotal lobe with two large indistinct lateral marks and posterior dorsal mark narrowly divided centrally. Pair of small mounds dorsally on middle pronotal lobe, bearing tiny tubercles. Synthorax brown with pale yellow-green markings as follows ( Figs 73 , 83 ): short mesothoracic collar, broadly divided at middorsal carina, joined to narrow dorsal thoracic stripes, slightly tapering toward wing bases, extending beyond level of apex of antealar crest, terminating just short of antealar carina, inner margins parallel. No antehumeral markings but tiny yellow spot at antealar carina in this position. Narrow pale marking along mesopleural suture, probably due to postmortem discoloration. Stripe running most of length of mesepimeron. Metepisternum with indistinct pale area below spiracle, small yellow mark near antealar carina. Broad stripe occupying much of metepimeron. Mesokatepisternum, metakatepisternum obscurely brown and pale. Venter pale. Legs (only middle leg still attached on left, left anterior leg detached at trochanter but still present in bag, left posterior leg used for DNA extraction) robust and relatively short. Pale brown, likely much darker when mature, tarsal claws pale basally, tips brown, teeth black. Tarsus of left anterior leg with only three basal spines, claws short without tooth, tarsus of right posterior leg with few spines, claws short, lacking teeth; tibia of same leg abnormally short. Wings: sectors of arculus separated at origin with 5 cross veins before first bifurcation of superior sector in Fw, 3 (right) or 4 (left) in Hw. Discoidal field with 2 rows of cells from origin, transitioning to 3 well before nodus in all wings. 15 (left) or 16 (right) Ax in Fw, 11 (left) or 13 (right) in Hw, 13 Px in Fw, 14 (left) or 13 (right) in Hw. Pt white, covering ca 4 underlying cells.

Abdomen. Compressed due to teneral condition. Dark brown with pale markings as follows: S1 with lateral mark and dorsal mark. S2 faint pale lateral stripe running from small auricle to apex. Lateral basal marks on S3–6, becoming smaller on successive segments. S2–7 with narrow middorsal line, widest on S2. S8–10 entirely dark. Cerci simple conical, tapering to sharp tip, longer than S10. Vulvar scale distorted but at least slightly longer than S9, not fit for illustration.

Measurements (mm). Hw 39, abdomen excluding anal appendages 39.5.

Remarks. This species is remarkable for its head structures and for the apparent reduction of pale markings on the metepisternum. It is clearly distinct from all known species morphologically, and in the two molecular markers examined (see Figs 1 , 2 , 3 ), however we will wait for a male specimen to become available before naming it. The peculiarities noted for the left anterior and right posterior legs appear to be merely deformities.

Our molecular analyses suggest that this species is most closely related to L. pendleburyi . At present this species is known from a single location in Pulong Tau National Park in the Tama Abu Range, Sarawak ( Fig. 128 ).

Figures

FIGURE 2. ITS gene tree for 20 specimens of Leptogomphus and three outgroup taxon.The best Maximum Likelihood tree is shown, with posterior probabilities from the Bayesian Inference analysis also depicted on the branches. Bootstrap values and posterior probabilities are shown if less than 100 or 1.0 respectively. RMNH collection codes are shown for each specimen, as well as the sex of the specimen and an indication of where it was collected.

FIGURE 3. Phylogenetic reconstruction for 30 specimens of Leptogomphus and three outgroup taxa using the combined COI+ITS dataset. The best Maximum Likelihood tree is shown, with posterior probabilities from the Bayesian Inference analysis also depicted on the branches. Bootstrap values and posterior probabilities are shown if less than 100 or 1.0 respectively. RMNH collection codes are shown for each specimen, as well as the sex of the specimen and an indication of where it was collected.

FIGURE1. COI gene tree for 29 specimensof Leptogomphusand three outgroup taxon.The best Maximum Likelihood tree is shown, with posterior probabilities from the Bayesian Inference analysis also depicted on the branches. Bootstrap values and posterior probabilities are shown if less than 100 or 1.0 respectively. RMNH collection codes are shown for each specimen, as well as the sex of the specimen and an indication of where it was collected.

FIGURES18–23.Female headdorsal:(18) L.coomansi SAR11_12_GOM48;(19)L.mariaeholotype;(20) L.sp.cf coomansi PomS260; (21) L. pasia holotype; (22) L.sii paratype SAR13_14_GOM44; (23) L. species SAR11_12_GOM33.

FIGURES28–31. Female head dorsaldetail; h—occipital horn; ot—occipital tube; p—pit; s—occipital spur; t—tubercle;thtubercle horn: (28) L. coomansi SAR11_12_GOM48; (29) L. mariae holotype; (30) L. sp. cf coomansi PomS260; (31) L. species SAR11_12_GOM33.

FIGURES 36–41. Female head frontal: (36) L. coomansi SAR11_12_GOM48; (37) L. mariae holotype; (38) L. sp. cf coomansi PomS260; (39) L.pasia holotype; (40) L.sii paratype SAR13_14_GOM44; (41) L.species SAR11_12_GOM33.

FIGURES 46–51. Female head frontal detail; h—occipital horn; ot—occipital tube; t—tubercle; th—tubercle horn: (46) L. coomansi SAR11_12_GOM48; (47) L pendleburyi SAR16_GOM8; (48) L. schieli paratype SAR15_GOM6; (49) L. species SAR11_12_GOM33; (50) L. williamsoni SAR13_14_GOM51; (51) L.sp. cf williamsoni SAR11_12_GOM59.

FIGURES 68–73. Female synthorax dorsal: (68) L. coomansi SAR11_12_GOM48; (69) L. mariae holotype; (70) L. sp. cf coomansi PomS260; (71) L.pasia holotype; (72) L.sii paratype SAR13_14_GOM44; (73) L.species SAR11_12_GOM33.

FIGURES 78–83. Female synthorax lateral: (78) L. coomansi SAR11_12_GOM48; (79) L. mariae holotype, right hand side, flipped for consistency; (80) L. sp. cf coomansi PomS260; (81) L. pasia holotype; (82) L. sii paratype SAR13_14_GOM44; (83) L.species SAR11_12_GOM33.

FIGURE128. Distributionof L. pendleburyi (yellowcircle), L. schieli (black square) and L. species from Pulong Tau National Park, Sarawak (white square).