Burmagomphus magnus, Zhang, Hao-Miao, Kosterin, Oleg E. & Cai, Qing-Hua, 2015

Zhang, Hao-Miao, Kosterin, Oleg E. & Cai, Qing-Hua, 2015, New species and records of Burmagomphus Williamson, 1907 (Odonata, Gomphidae) from China, Zootaxa 3999 (1) : -

Burmagomphus magnus sp. nov.

Figures 11–18 , 36

Etymology. magnus is a Latin adjective meaning ‘big’, chosen because the species described is among the largest in its genus.

Material examined. Holotype: ♂, Huayudong (22°40’20’’N, 103°56’16’’E), altitude 150 m, Nanxi Town, Hekou County, Hani-Yi Autonomous Prefecture of Honghe, Yunnan Province, China, 0 5 May 2010, Hao-miao Zhang leg.; Paratypes: 4♂, same data as holotype; 1♂, 1♀, same site and collector, 0 3 May 2014; 1♂, same site and collector, 0 4 May 2014; 1♂, same site and collector, 0 8 May 2014; 1♂, 1♀, same site and collector, 11 May 2014.

Holotype male: Head. Eyes green while alive ( Fig. 36 ). Face black with pale yellow markings ( Fig. 11 ). Labium largely pale yellow. Mandible bases pale yellow. Labrum with a pair of very large oval pale spots. Anteclypeus entirely black. Postclypeus almost black with a short and fine stripe on lower margin centrally and very small rounded spots on either side. Top of frons with a very broad yellow stripe. Vertex black with paired tubercles behind and centrally of lateral ocelli. Occiput black, with hind margin straight, fringed with long setae.

Thorax. Generally black with pale yellow markings ( Figs 12 , 36 ). Prothorax with two pale spots on each side of middle lobe. Synthorax with mesothoracic collar interrupted at mid point, dorsal stripes not connecting with collar stripes. Antehumeral stripe extends throughout mesepisternum length but isolated from its continuation on mesokatepisternum. Sides of synthorax largely pale yellow with two broad black stripes, one along the interpleural sutre, the other along the metapleural suture, thus forming three broad yellow stripes. Mesokatepisternum and metakatepisternum with large yellow spots. Legs largely black. Coxae with yellow spots in all legs, and fore leg femur with inner yellow stripes.

Wings. Hyaline, venation black. Forewings: 13 (left) and 15 (right) antenodals above Sc and 14 (left) and 13 (right) antenodals below Sc; 12 (left) and 13 (right) postnodals above R1, 11 (left) and 13 (right) postnodals below R1. Hindwing: 10 antenodals above Sc, 9 antenodals below Sc; 10 (left) and 11 (right) postnodals above R1, 14 (left) and 13 (right) below R1. Triangles not crossed. Median space without crossvein. Anal loop one-celled. Anal triangle 3-celled. Pterostigma brown, well braced, below covering 3 (left) and 4 (right) cells on forewings, 4 cells on hindwings.

Abdomen. Black with pale marking as follows ( Fig. 36 ): S1 with a large spot laterally and a dorsal spot connecting with dorsal spot in basal half of S2; sides of S2 with two oval pale spots, proximal one including auricles; S3–7 with basal spots; S9 with a very large dorsal spot posteriorly, without a spine; S10 and anal appendages black. Cerci of about same length as S10 but longer than epiproct, in dorsal view tapering and almost parallel, but apical 1/4 slightly curved outwards ( Fig. 13 ); when viewed laterally, lower margin with a short rounded swelling at about 2/3 of cercus length ( Fig. 14 ). Epiproct with a deep and very even median concavity, thus forming two divergent branches with convex outer margins, in lateral view their tips slightly curved upwards. Posterior hamulus relatively narrow at base and strongly broadening apically, with its anterior side convex in apical half and posterior and apical sides straight forming an extended, acute but rounded angle; antero-apical spine strong, straight and rather long ( Fig. 15 ).

Female: Head and thorax color pattern similar to male ( Figs. 16–17 ), vertex with two long and slightly curved divergent horns behind lateral ocelli ( Fig. 16 ). Wing bases slightly tinted with amber. Abdomen with a big yellow spot on either side of S1 and S2. S1 with a dorsal spot connecting with dorsal spot in basal 2/3 of S2; S3–7 with a basal ring; S9 with a large semicircular dorsal spot with uneven margins posteriorly; S10 with three small semicircular spots along posterior margins. Vulvar lamina shown in Fig. 18 .

Variation in paratypes. Most male paratypes possess smaller yellow spots on S10, and the yellow paired stripes on labrum are narrower.

Measurements (mm). Holotype male: total length 53.0, abdomen (including anal appendages) 39.0, hind wing 31.5; Paratype: males: total length 50.0–53.0, abdomen (including anal appendages) 37.0–40.0, hind wing 29.5–31.5; females: total length 51.0–52.0, abdomen (including anal appendages) 38.5–39.0, hind wing 33.5–34.0.

Differential diagnosis. B. magnus is close to B. intinctus and differs from it by: (i) longer and tapering cerci, extending caudally beyond the epiproct arms (more evenly thick and extending to a level with the epiproct arms in B. intinctus , figs. 6–7); (ii) the cercus ventral swelling long and rounded (tooth-like in B. intinctus , fig. 7); (iii) the cerci apices more processed in lateral view and slightly divaricate in dorsal view (with shorter, blunt and straight apices in B. intinctus , figs. 6–7); (iv) epiproct arms with convex outer margins in dorsal view (nearly straight in B. intinctus , fig.6) and with apices not hooked inward in dorsal view and up in apical view as in B. intinctus (figs. 6– 7). From B. arvalis , B. magnus well differentiated by completely black occiput without a light spot. B. magnus is much larger (male abdomen 37–40 mm; male hindwing 29.5–31.5 mm) than B. arvalis and B. apricus but approaches B. intinctus (male abdomen 36.5 mm, male hindwing 31–32 mm) in size.

Female of B. magnus is similar to female of B. dentatus but has the pair of vertex horns set more widely apart from each other, so that their bases are disposed behind the lateral ocelli and set wider than the occiput, with their apices divergent. Female of B. intinctus well differentiated from both above-mentioned species by a pair of double short horns behind each lateral ocellus, widely separated by a long transverse vertex ridge ( Fig. 9 ).

Habitat. The habitat for this species was a lowland river. In some section the river was wide and deep, and males of B. magnus were found at sandy beach. Some other sections of the river were much narrower, with a lot of big boulders and rocks, and a great number of males were found perching on them. The males held their territory and perched for a long time, but they sometimes patrolled a short distance. Males were found during the daytime from 09:00 to 17:00 but absent during noontime, when the females appeared for laying eggs.

Distribution. Currently known only from eastern Yunnan province, China.

Figures

FIGURES 11 – 18. Burmagomphus magnus sp. nov., holotype male (11 – 15) and paratype female (16 – 18): (11) head in frontal view; (12) thorax in lateral view; (13) appendages in dorsal view; (14) appendages in lateral view; (15) posterior hamulus in lateral view; (16) head in frontal view; (17) synthorax and basal abdominal segments in lateral view; (18) S 8 – 10 in ventral view.

FIGURES 34 – 39. Living photos of new species: (34 – 35) Burmagomphus apricus, holotype male, Menglun Town, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province, 18 May 2013; (36) B. magnus, paratype male, Nanxi Town, Hekou County, Hani-Yi Autonomous Prefecture of Honghe, Yunnan Province, China, 0 4 May 2014; (37) B. dentatus, paratype male, Libo County, Guizhou Province, China, 10 June 2010; (38 – 39) B. latescens, holotype male, Mengding Town, Lincang City, Yunnan Province, China, 19 September 2014. Photo 37 was taken by Samson So, all the others by Hao-miao Zhang.

FIGURES 6 – 10. Burmagomphus intinctus (Needham, 1930), details of specimens from Jingning, Lishui City, Zhejiang Province: (6) male appendages in dorsal view; (7) male appendages in lateral view; (8) male posterior hamulus in lateral view; (9) female head in frontal view; (10) female S 8 – 10 in ventral view.