Leptogomphus Selys in Borneo 1878
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

description: Leptogomphus sp. cf coomansi Laidlaw, 1936
(Figs 1, 2, 3, 12, 20, 30, 38, 54, 61, 70, 80, 126)
Leptogomphus pasia;—van Tol 1990: 97, 98 (part, male Danum Valley, Sabah, excluded from type series), Table 2 (part, male characters);—? Kalkman 2005: 14 (male, Kuala Belalong Field Studies Centre, Brunei).
Leptogomphus cf pasia;—van Tol 1990: 99, 102, Figs 6, 8, 16, 32, 33 (refers to same male specimen as above);—Dow & Ngiam 2015: 24 (Sungai Sii, upper Baram, Sarawak).
Material studied. Sarawak, Malaysia: 1 ♂ (teneral; SAR 15_GOM14), Sungai Selabi, Ulu Mujok, LEWS, Sarikei Division, 1.6929N, 112.16291E, 1 viii 2015, leg. RA. Dow, in collection Dow; 1 ♀ (SAR 15_GOM20), Sungai Temurok and tributaries inside Lanjak Entimau Wildlife Sanctuary boundary, Ulu Mujok, Sarikei Division, 1.70348N, 112.13513E, 4 viii 2015, leg. R.A. Dow, in collection R.A. Dow; 1 ♂ (SAR 07_8_GOM49), stream in unplanted valley, block E2N, Tubau, Sarawak Planted Forest Project, Bintulu Division, 3.113N, 113.662E, 20 x 2008, leg. A. Juhin, in collection Dow; 1 ♀ (SAR 15_GOM40), Sungai Lamah, mid Baram, Miri Division, 3.53978N, 114.22956E, 7 ii 2015, leg. L. Southwell, in collection Dow; 1 ♂ (teneral; SAR 11_12_GOM25), Long Liau/Sungai Dapoi area, ulu Tinjar, Miri Division, (coordinates not available), 4–7 v 2011, leg. L. Southwell, in collection Dow; 1 ♂ (SAR 09_10_GOM37: RMNH.INS.501357), stream in Lio Mato water catchment area, Lio Mato, Upper Baram, Miri Division, 3.163N, 115.235E, 13 x 2009, leg. R.A. Dow, in RMNH; 1 ♂ (SAR 13_14_GOM50), tributary to Sungai Sii downstream from Camp, Upper Baram, Miri Division, 2.99147N, 114.90256E (Sungai Sii), 17 vii 2014, leg. R.W.J. Ngiam, to be deposited in ZRC; 1 ♀ (PomS260-2014, used in illustrations), steep tributary of Deer Cave River, GMNP, Miri Division, 4.0297N, 114.8355E, 22 iv 2014, leg. P.O.M. Steinhoff, in collection Steinhoff.
Sabah, Malaysia: 1 ♂, brooklet crossing West Trail, near Sungai Segama, Danum Valley, 4.91667N, 117.66667E (Danum Valley), 170 m, 2 v 1987, leg. J. van Tol, in RMNH; 1 ♀, Sungai Palum Tambun, Danum Valley, 4.91667N, 117.66667E (Danum Valley), 150–160 m, 23 iv 1994, leg. M. Hämäläinen, in RMNH; 1 ♂ (SAB 12_GOM4; RMNH.INS.507752, used in illustrations), Kimamabang waterfall stream, Inobong, Crocker Range National Park, 5.9N, 116.117E (Inobong), 18 ix 2012, leg. R.A. Dow, in RMNH.
Descriptive remarks. Morphologically, males of this taxon differ from L. coomansi only in the presence of a complete antehumeral stripe; other characters fall within the range of variation in L. coomansi. The middorsal stripes are narrower than the average seen in L. coomansi, and in the male illustrated in Figure 54 they are just disconnected from the mesothoracic collar, but this is a condition approached in at least one specimen of L. coomansi examined (see the variation section under that species). In all males examined the arms of the epiproct are at the least curved end of the spectrum seen in L. coomansi. Females are associated with the males by supposition on the basis of their complete antehumeral stripes and the possession of an entirely black clypeus as in the males (but in L. coomansi females only seen in the holotype of L. mariae and one other specimen). These females also differ in the structures of the dorsum of the head from L. coomansi; they also possess pits, but the pits are orientated parallel to the longitudinal axis of the head (more transverse in definite L. coomansi) and run right up to rear of the lateral ocelli (separated from the lateral ocelli in definite L. coomansi), and the tubercles are correspondingly narrower (Fig. 30); occipital horns are not present in any of the specimens examined except the female from the Danum Valley, which has one broken occipital horn. The Danum Valley female is also unusual in that there are small areas at the rear of the pits that are raised up, forming additional small tubercles or very small horns; the sternum of S8 was not checked in this specimen. The other three females listed under this taxon are teneral (so reliable measurements cannot be given); the vulvar scale is not suitable for figuring in any, but appears similar to that it L. coomansi, but possibly slightly longer. The sternum of S8 is only exposed in the female from Sungai Lamah, which is the most teneral of the three, and severely distorted; the curious tubercle seen on the sternum of S 8 in L. coomansi might be present but not fully inflated, however this might be an artefact of the folding and distortion of the segment.
Measurements (mm). Males: Hw 29.5–31.5, abdomen excluding anal appendages 36–39.5, Ax 16–18 Fw, 11– 12 Hw, Px 10–12 both pairs. Females: teneral and not suitable for measuring.
Other remarks. In the molecular results, this taxon is not clearly distinguished from L. coomansi in COI (Fig. 1; possibly this is the result of introgression), but is weakly separated from it in ITS (Fig. 2); in the combined analysis (Fig. 3) it appears as the close sister to L. coomansi. Since only two samples of L. sp. cf coomansi are included in these analyses it is not possible to have great confidence that the inclusion of more samples would not result in a blurring of the distinction seen in ITS and the combined analysis presented here. Since none of the supposed females are included in the analyses, no light is thrown on their association with the males.
The status of this taxon is left open here until more material becomes available; an expanded molecular analysis is needed to resolve the issue of its relation to L. coomansi. One or both sexes may ultimately prove to be merely uncommon extremes of variation in L. coomansi, but may also prove to be a distinct, but recently separated, biological species.
This taxon is know from Sabah and Sarawak east of the Lupar River (see Fig. 126). In Sarawak it occurs at some of the same locations as L. coomansi, but appears to be much scarcer.
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 214-215, DOI: 10.11646/zootaxa.4358.2.1, http://zenodo.org/record/1067996