Burmagomphus chaukulensis Joshi, Ogale & Sawant

Joshi, Shantanu, Sawant, Dattaprasad, Ogale, Hemant & Kunte, Krushnamegh, 2022, Burmagomphus chaukulensis, a new species of dragonfly (Odonata: Anisoptera Gomphidae) from the Western Ghats, Maharashtra, India, Zootaxa 5133 (3), pp. 413-430 : 414-429

publication ID	https://doi.org/ 10.11646/zootaxa.5133.3.6
publication LSID	lsid:zoobank.org:pub:580FE77E-F1FE-4807-8A62-EA27CEB04B2A
DOI	https://doi.org/10.5281/zenodo.6524173
persistent identifier	https://treatment.plazi.org/id/227087A8-354F-B85C-FF55-8A57FE167BF4
treatment provided by	Plazi
scientific name	Burmagomphus chaukulensis Joshi, Ogale & Sawant
status

Treatment

Burmagomphus chaukulensis Joshi, Ogale & Sawant View in CoL

( Figs. 1–8 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 )

Holotype. ♂ ( IBC-BN809 ), Cement Sakaw , Chaukul , Sawantwadi Taluka, Sindhudurg District, Maharashtra, India (15.9193 N, 74.0259 E; Alt: 805 m), 4.vi.2020, Hemant Ogale leg. GoogleMaps

Paratypes. ♂ ( IBC-BN810 ) , ♀ ( IBC-BN812 ), the location, date of collection, and collector the same as for the holotype .

♂ ( IBC-BN811 ) , ♀ ( IBC-BN813 ) the location and collector the same as for the holotype, date of collection 6.vi.2021 .

♂ ( IBC-BN814 ), Mulwand , Sawantwadi, Sindhudurg, Maharashtra, India (15.9860 N, 74.0300 E; Alt: 690 m), 10.vi.2021, Hemant Ogale leg. GoogleMaps

Etymology. The species epithet is derived from the type locality (adjective in genitive).

Proposed English Name. Spiny Horntail: specific name is given for the spines on posterior hamuli, and the name ‘Horntail’ is proposed for the genus based on the shape of caudal appendages in absence of any current common name for the genus.

Description of holotype IBC-BN809 ( Figs. 1–2 View FIGURE 1 View FIGURE 2 )

In life, black with yellow markings tinted pale green. Post-mortem, the markings from thorax till abdominal segment S2 became greenish-yellow, the rest pale brownish-yellow.

Head ( Fig. 1a View FIGURE 1 ). In life eyes green, post-mortem dark brown. Face black marked with yellow: entirely on labium, paired spots on labrum and large spots on postfrons connected medially. First antennal segment striped brown, rest black. Median ocelli triangular, wider than lateral. Vertex, occiput and rest of head black.

Thorax ( Fig. 1b View FIGURE 1 ). Prothorax black with yellow markings medially at anterior margin of anterior lobe, and laterally on middle lobe. Pterothorax marked yellow with mesothoracic collar. Mesepisternum with dorsal slightly oblique stripes, small spots wing bases, small oval spot near mesothoracic collar laterally. Dorsal carina processed into a spine. Mesepimeron with a broad stripe, slightly broader and rounded anteriorly. Mesepisternum with an irregular yellow stripe made up of three sections: middle section large, anterior section short and pointed, slightly disconnected from middle section. Metepimeron yellow. Coxae yellow near base, rest of legs black.

Wings ( Fig. 2 View FIGURE 2 ). Hyaline, median space tinted pale yellow. Pt dark brown. Cubito-anal space with one crossvein. Ax [1 st and 5 th primary]: 14 (left)—13 (right) in FW, 10 in HW; Px: 10 in FW (two incomplete stems), 11 (left)—10 (right) in HW. Crossveins below subcosta 13 in FW, 12 in HW. Base of HW excavate with tornus forming an obtuse angle. Triangle crossed only in right HW. Anal triangle three celled with a central rectangular cell. Anal loop absent. Discoidal field commencing with two cells in FW and three cells in HW.

Abdomen ( Fig. 1c–d View FIGURE 1 ). Black with yellow markings (copper-yellow post-mortem). Lateral and dorsal markings on S1-2. S1 with a triangular markings dorsally; marking on S2 broad at posterior end, thinner and tapering posteriorly, ending before margin. S3–7 with basal rings, pointed posteriorly on dorsum of S2–3, S9 with a large trilobed marking at posterior margin.

Accessory genitalia ( Fig. 3a–e View FIGURE 3 ). Anterior hamuli short, broader at base, tapering at apices, dark brown and covered with thick setae at apices. Posterior hamuli nearly rectangular, wide with an apical ridge and sharp spines at anterior and posterior ends, anteriorly sharply curved with a single apical spine; posteriorly with variable number of spines: 1 (left) or 2 (right). Vesica spermalis black, V2 internally and V4 brown. V1 large, rounded; base slightly bi-lobed, covered with setae. V2 broader at base, curved at the junction with V3. V3 thin, constricted at the junction with V4. V4 apically with paired rectangular ridges at base. Distal segment translucent brown, with rounded lateral flaps; apices bifurcated with two protuberances giving rise to a pale brown, thick and coiled filament.

Caudal appendages ( Fig 1e–g View FIGURE 1 ). Both black, divaricate with apices curved inwards. Cerci broad at base, apices with a sharp inwardly curved spine, outer margin expanded into two lobes. Paraproct ca one and half times longer than cerci, laterally flattened, broad at base, rounded in the middle, ending in a thin, upwardly curved spine.

Measurements (in mm). Abdomen + caudal appendages= 30.7, FW= 27.7, HW= 25.

Variation in paratype males ( Figs. 4–5 View FIGURE 4 View FIGURE 5 )

Thoracic markings consistent among males. Number of spines on posterior corner of left and right hamuli is variable, two on both sides in IBC-BN810, 2 (left) and 3 (right) in IBC-BN811, and 1 on both sides in IBC- BN814.

IBC-BN810 is presumably a younger male as indicated by the shriveled up abdomen, sheen to the body, and translucent pale brown Pt ( Fig. 4a View FIGURE 4 ). Pt light brown in IBC-BN814.

Ax [1 st and 5 th primary]: 13–14 (left): 13–14 (right) in FW, 9–10 (left): 9–10 (right) in HW; Px: 10–11 (left): 10–12 (right) in FW, 9–11 (right): 9–11 (left) in HW. Crossveins below subcosta 12–15 in FW, and 9–12 in HW.

Measurements (in mm). Abdomen + caudal appendages = 31.3–32.6, FW = 27.8–28.9, HW = 26.5–27.6.

Description of paratype female IBC-BN812 ( Figs. 6–7 View FIGURE 6 View FIGURE 7 )

Head ( Fig. 6a View FIGURE 6 ). Black. Eyes green in life dark brown post-mortem, marked yellow as follows: labium & mandibles, elongated spots on lateral margins of labrum, faint miniscule markings- medially on anteclypeus and base of postclypeus and latero-apical margins of postclypeus, postfrons with two large oval markings disjointed medially. Paired, small black postocellar spines.

Thorax ( Fig. 6b–e View FIGURE 6 ). Prothorax ( Fig. 6d View FIGURE 6 ) black, yellow at anterior margin and rectangular markings on mediolateral lobes. Pterothorax marked yellow as in male: mesothoracic collar, short dorsal stripes, small spots near wing bases, small median stripes at margin of mesepisternum, broad stripe on mesepimeron, metepisternum with an irregular stripe: broad at base, constricted then broadening again, pointed at curved at spiracle, metepimeron completely yellow. Coxae and base of femur yellow; rest of legs black.

Wings ( Fig. 6c View FIGURE 6 ). Unevenly tinted pale yellow at bases, especially in median and subcostal areas. Ax [1 st and 5 th primary]: 15 in FW, 11 (left)—10 (right) in HW; Px: 11 (left)—13 (right) in FW, 11 (left)—12 (right) in HW. Crossveins below subcostal 14 in FW, 10-11 in HW. Pt brown. Triangle not crossed. One crossvein in cubito-anal space.

Abdomen ( Fig. 6c, e View FIGURE 6 ). Black, marked yellow as follows: S1–2 lateral and dorsal stripe, basal rings on S3– 7, posterior margin of S9 apically, and paired markings on posterior margin of S10 tapering towards the center.

Caudal appendages ( Fig. 7a–c View FIGURE 7 ). Black, cerci broad at base, pointed at apices, curved slightly inwards.

Vulvar scale rounded, with a semicircular notch at middle.

Measurements (in mm). Abdomen + caudal appendages = 32.4, FW = 27.6, HW = 29.4.

Differences in the paratype female IBC-BN813 ( Fig. 8 View FIGURE 8 )

Ax [1 st and 6 th primary]: 16 (left)—15 (right) in FW, 11 in HW; Px: 14 in FW, 15 (left)—14 (right) in HW. Crossveins below subcosta 15 in FW, 11 (left, 5 th crossvein looped)—12 (right) in HW. Measurements (in mm). Abdomen + caudal appendages = 34.1, FW = 28.7, HW = 30.2-31.

Differential diagnosis. Kosterin et al. (2015) proposed a grouping of Burmagomphus spp. based on thoracic markings (see Figs. 11–12 View FIGURE 11 View FIGURE 12 ) that we follow here. Group 1 comprises of species with fused dorsal and antehumeral stripes (representatives in India: B. divaricatus , B. pyramidalis pyramidalis , B. hasimaricus ). In Group 2, the dorsal and antehumeral stripes are separated and short (e.g., B. cauvericus Fraser, 1926 , and B. laidlawi ; both endemic to Western Ghats). Group 3 exhibits an extensive antehumeral stripe that is not connected to the dorsal stripe (the sole Indian representative: B. sivalikensis Laidlaw, 1922 ). Based on short, unconnected antehumeral and dorsal stripes ( Figs. 1 View FIGURE 1 , 4 View FIGURE 4 ) the newly described B. chaukulensis belongs to the Group 2 along with the two Western Ghats endemics: B. cauvericus and B. laidlawi .

Burmagomphus chaukulensis is most similar to B. laidlawi in terms of thoracic markings ( Figs. 1 View FIGURE 1 , 10–12 View FIGURE 10 View FIGURE 11 View FIGURE 12 ), but the following characters easily distinguish it from B. laidlawi : (a) spines on both ends of posterior hamuli in B. chaukulensis , spines only on anterior side in B. laidlawi ( Figs. 3 View FIGURE 3 , 5 View FIGURE 5 , 10 View FIGURE 10 ), (b) shape of V3–4 tubular in B. chaukulensis with apical filament thicker at base, versus V4 small, saddle-shaped, with thin apical filament in B. laidlawi ( Figs. 3c–e View FIGURE 3 , 10c–d View FIGURE 10 ), (c) cerci sharply pointed to a spine with a bilobed base at apices of B. chaukulensis , versus inwardly curved apices with small basal spines at apices in B. laidlawi ( Fig. 13 View FIGURE 13 ), (d) stripe on mesepisternum reduced and pointed anteriorly in B. chaukulensis ,versus broad, rounded and not pointed anteriorly in B. laidlawi ( Fig. 11–12 View FIGURE 11 View FIGURE 12 ), and (e) markings on S8 (unmarked in B. chaukulensis , yellow posterior margin, dorsal markings at base and two spots in B. laidlawi ). Males of B. chaukulensis are slightly smaller than males of B. cauvericus and B. laidlawi (abdomen length 30–31.5 in B. chaukulensis , versus 35 in B. cauvericus and 33 in B. laidlawi .

Burmagomphus chaukulensis differs from B. cauvericus in terms of: (a) smaller size (abdomen length 30– 31.5 versus 35 in B. cauvericus ), (b) posterior hamuli with spines on both ends in B. chaukulensis , no spines on posterior end in B. cauvericus , and (c) thoracic stripes on mesepimeron and metepisternum separated from each other and parallel in B. chaukulensis , fused at base in B. cauvericus ( Figs. 11–12 View FIGURE 11 View FIGURE 12 ). Burmagomphus chaukulensis can be distinguished from Burmagomphus spp. of Group 2 outside of the Western Ghats, viz., B. pyramidalis Laidlaw, 1922 , B. asahinai Kosterin et al., 2012 , B. bashanensis Yang & Li, 1994 , by the thoracic maculation and the shape of posterior hamuli (wide with spines at two ends, see Kosterin et al. 2012).

Female of B. chaukulensis can be distinguished from B. laidlawi by: (a) the shape of the short stripe on metepisternum (pointed anteriorly and ‘sword-shaped’ in B. chaukulensis . broad in B. laidlawi ; Figs. 6 View FIGURE 6 , 8 View FIGURE 8 , 10 View FIGURE 10 ), and (b) the markings of S9–10 (S10 with prominent paired spots in B. chaukulensis , reduced in B. laidlawi ). Female of B. chaukulensis is similar in size to B. laidlawi , but smaller than B. cauverius (abdomen length: 32-33 in B. chaukulensis , 35 in B. cauvericus , and 32 in B. laidlawi ).

Burmagomphus chaukulensis female has a straight broad stripe on mesepisternum, whereas B. divaricatus , B. hasimaricus and B. pyramidalis have a bifurcated stripe on mesepisternum. Burmagomphus chaukulensis female ( Figs. 6 View FIGURE 6 , 8 View FIGURE 8 ) can be easily distinguished from females of B. cauvericus , B. divaricatus , B. hasimaricus and B. pyramidalis by the parallel thoracic stripes (the latter species have stripes on mesepimeron and metepisternum fused).

Habitat and habits: The type locality is a hill stream (805 m ASL), locally known as ‘Jambhulkond’ (roughly translating to ‘a stream surrounded by Syzygium trees’, Fig 14a View FIGURE 14 ). This particular stretch is approx. 500m in length with forested hill slopes on both sides. Large rocks cover the streambed, and odonates can be seen commonly basking on exposed parts of these rocks. Along with B. chaukulensis , Heliocypha bisignata (Hagen in Selys, 1853), Orthetrum luzonicum (Brauer, 1868) , Pseudagrion indicum Fraser, 1924 , P. rubriceps Selys, 1876 , Trithemis festiva (Rambur, 1842) , T. kirbyi Selys, 1891 , Vestalis apicalis Selys, 1873 and V. gracilis (Rambur, 1842) also inhabit this stream. The second locality (Mulwand) is a sacred grove, from which a perennial river originates. The upstream stretches of this river are rocky, surrounded by tropical evergreen and moist deciduous forests. The downstream stretches are a shallow wetland with aquatic grasses ( Fig. 14b View FIGURE 14 ). We observed B. chaukulensis in high numbers at Chaukul from the first week of June to the first week of July. Teneral individuals were found in the first week of June. Nearly 30 individuals could be observed on a single day in the first week of July. After mid-July, we could not observe a single individual at Chaukul. This species thus appears to breed during southwest monsoon, with peak activity in mid June to early July, just before the southwest monsoon peaks in the region.

Males mostly perch on large rocks in the riverbed, sometimes settling on nearby bushes. This species is most active between 10 am and 1 pm. We observed 3-4 mating pairs during this time, but no oviposition. At Mulwand, three males and one mating pair were observed on 10 th June 2021.

Distribution, With the addition of B. chaukulensis there are now three endemic Burmagomphus spp. in the Western Ghats. B laidlawi is found throughout the Western Ghats whereas B. cauvericus is more restricted in it’s distribution. Burmagomphus pyramidalis is the only other species of Burmagomphus that occurs in Western Ghats and Peninsular India. All other species of the genus are found in Western and Eastern Himalaya. Burmagomphus divaricatus was recently reported from Nagaland, India ( Joshi et al. 2017). A distribution map of Burmagomphus spp. is provided in Fig. 15 View FIGURE 15 .