Gynacantha chaplini sp. nov. from Bangladesh 1st June 202195

Gynacantha chaplini sp. nov., a new from Bangladesh (: )

Md Kawsar Khan

Department of Biological Sciences, Macquarie University, N.S.W. 2109, Australia; Department of Biochemistry and Molecular Biology, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh;

Received 2nd July 2019; revised and accepted 16th March 2021

Abstract. Gynacantha chaplini sp. nov. is described based on a male collected from the north-eastern region of Bangladesh. Distinguishing features of the adult male are illustrated and discussed. Gynacantha chaplini sp. nov. is distinguished from its congeners by a dark brown trapezium-shaped mark on the postfrons. An updated key is provided to identify the males of the Gynacantha species known from South Asia (Bangladesh, Bhutan, India, Nepal, Pakistan, Sri Lanka). Further key words: Anisoptera, , conservation, diversity and distribution, South Asia

Introduction Gynacantha Rambur, 1842, is a large of the family Aeshnidae with 99 recognised species (Paulson & Schorr 2021). Most species of this genus are forest dwellers. They forage and mate at dawn and dusk, and females are often seen ovipositing in the early afternoon. Currently, 15Gynacantha spe- cies are known from South Asia (Kalkman et al. 2020). Of them, 11 species were documented by Fraser (1936). There have since been four new Gyn­ acantha species described from the region, namely: Gynacantha rammohani Mitra & Lahiri, 1975, from West Bengal, India; G. arnaudi Asahina, 1984, from Assam, India; G. andamanae Yeh & Veenakumari, 2000, from the An- daman and Nicobar Islands, India; and G. pallampurica Lahiri, Sandhu & Walia, 2007, from Himachal Pradesh, India. According to the IUCN Red List criteria, nine of those species are »Data deficient«, three are »Least con- cern«, and three species have not yet been assessed. Of the 15 species, eight

Odonatologica 50(1/2) 2021: 95-105Odonatologica – DOI:10.5281/zenodo.4746248 50(1/2) 2021: 95-105 96 Md K. Khan are endemic to India and one is endemic to Pakistan, while the remaining six species are more widespread (Table 1). To date, three species of Gynacantha have been recorded from Bangladesh (Shah & Khan 2020), viz. Gynacantha subinterrupta (Khan 2015b; Tuhin & Khan 2018), Gynacantha khasiaca (Khan 2015a, 2018) and ‘Gynacantha hyalina Selys, 1882’ (Chowdhury & Mohiuddin 2011; Khan 2015a). The latter probably belongs to , since G. hyalina is no longer regarded as occurring in South Asia (Kalkman et al. 2020) and Fraser’s (1936) keys are unreliable, at least in this instance. During a recent Odonata survey in the north-eastern region of Bangla- desh I collected an unusual Gynacantha species. After comparison with the described species, this is considered as new to science and described here.

Materials and methods The wing venation is described with the terminology following Theischinger & Hawking (2006). Coloration, body markings and mor- phological measurements are taken and described from the dried specimen. All measurement taken are provided in millimetres [mm].

Gynacantha chaplini sp. nov. (Figs 1, 2) Material studied Holotype ♂. Bangladesh, Sylhet division, Sylhet district, Khadimnagar Tea Garden, sandy forest stream, (24.923 N, 91.935 E; 50 m a.s.l.), 10-vii-2017, leg. Md Kawsar Khan. Deposited in the Australian Museum, Sydney, New South Wales, Australia.

Etymology The species is named in honour of the famous British actor and director, Sir Charles Spencer „Charlie“ Chaplin (masculine noun, singular in the geni- tive case). The trapezium-shaped marking of the postfrons of the new spe- cies resembles Chaplin’s iconic toothbrush moustache.

Male (holotype; Figs 1, 2) Head – Labium and labrum greenish; mandible pale brown; frons green- ish, without a T-shaped marking; postfrons with a dark brown trapezium-

Odonatologica 50(1/2) 2021: 95-105 Gynacantha chaplini sp. nov. from Bangladesh 97

Table 1. Gynacantha species in South Asia, with synonyms, distribution, and IUCN red list status (IUCN; DD – Data deficient, LC – Least concern, NA – Not assessed). The states from which the species are known are provided in parentheses.

Species Synonym Distribution IUCN Gynacantha apicalis Pakistan (Faisal- DD Fraser, 1922 abad) Gynacantha albistyla India (West Bengal DD Fraser, 1927 and Bihar) Gynacantha andamanae India (Andaman NA Yeh & Veenakumari 2007 island) Gynacantha arnaudi India (Assam) DD Asahina, 1984 Gynacantha bainbriggei India (Assam, DD Fraser, 1922 West Bengal) Gynacantha lyttoni India, Nepal LC Selys, 1891 Fraser, 1926 Gynacantha biharica India (Bihar) DD Fraser, 1927 Gynacantha dravida Bangladesh, India, DD Lieftinck, 1960 Sri Lanka Gynacantha incisura Bhutan, Myanmar, LC Fraser, 1935 Nepal, Thailand Bangladesh, Gynacantha khasiaca Gynacantha nigripes Bhutan, India, DD McLachlan, 1896 Martin, 1909 Myanmar, Nepal Gynacantha millardi India, Sri Lanka NA Fraser, 1920 Gynacantha odoneli India (West DD Fraser, 1922 Bengal) Gynacantha palampurica India (Himachal NA Lahiri, Sandhu & Walia, 2007 Pradesh) Gynacantha rammohani India (West DD Mitra & Lahiri 1975 Bengal) Gynacantha subinterrupta Gynacantha hanumana Bangladesh, India, LC Rambur, 1842 Fraser, 1922 Nepal shaped marking instead; eyes green, brown above; antennae dark brown; vertex greenish; occipital triangle small, greenish yellow.

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Thorax – Prothorax orange; median lobe of pronotum swollen. Synthorax or- ange without any marking, segment appear not well defined. Legs: femora of fore legs pale yellowish inside, dark brown outside, tibia, tarsus, and claws dark brown; femur of middle and hind legs orange, other segments dark brown.

Wings – Membrane transparent, veins black; nodal index: 18–20/19–14:19– 15/16–17; pterostigma brown, overlaying five cells in fore wing and four cells in hind wing; cubital cross-veins 7–8/6–7; triangles with 5 cells, hyper-trian- gles with 5–5/5–4 cells; 3–5 rows of cells between IR2 and Rspl, 4–5 rows in the right wings, 3–4 rows in the left wings; anal loop with 9 cells in the left wing and 12 cells in the right wing; anal triangle three-celled in both wings.

Abdomen – The pattern of each abdominal segment is well defined. Lat- erally blue stripes present on the anterior border of S4–S8. S1 unmarked and orange; S2 dorsally black with a transverse yellow line in the middle, blue markings present in the apical portion laterally; auricles dorsally and ventrally greenish blue with five well defined teeth; denticles present along margin of the genital fossa (in between anterior and posterior hamules). Proximal segments of vesicula spermalis thick, square-shaped, light yellow, middle segments brown, swollen, distal segments dark brown, apical seg- ment swollen, light yellow. S3 constricted, dorsally black and unmarked, anterior half laterally blue; S4 dorsally black, unmarked; S5 dorsally black with two small blue spots adjacent to the apical border; S6–S9 with ground colour black, two triangular blue markings near apical border; S10 black, unmarked, 1.5 mm long. Cerci black, 4.9 mm long, no incision on the inner side, basally thick, broadening gradually toward tip, apex pointing down- ward; epiproct white with brown tip, less than half the length of cerci, ba- sal third broad and becoming gradually narrower toward apex, apical third finger-shaped, apex roundly blunt.

Measurements [mm]: Total length 63.3; abdomen length including caudal appendages 53.4; fore wing 40.1; hind wing 40.1; cerci 4.9; epiproct 2.1.

Female Unknown.

Odonatologica 50(1/2) 2021: 95-105 Gynacantha chaplini sp. nov. from Bangladesh 99

Figure 1. Gynacantha chaplini sp. nov., holotype male. A – in life; B – view, lateral, preserved; C – head, dorsal; D – caudal appendages, dorsal. Photos: MKK

Figure 2. Gyn­ acantha chap­ lini sp. nov., holo­type male: A – head, dorso- anterior view showing mark on frons; B – S1–S3, ventral; C – S1–S3, dor- sal; D – caudal a p p e n d a g e s , dorsal; E – cau- dal appendages, lateral; F – Pe- nis, lateral.

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Habitat The single known male of Gynacantha chaplini sp. nov. was perched on a plant over the streams besides the Khadimnagar Tea Garden near the Khadim­nagar National Park, Sylhet, Bangladesh (Fig. 3). The streams are locally known as ‘chora’ and drain into the Surma river. The climate of the area is warm and humid with an average daily maximum temperature of 30.7°C and an average annual rainfall of 3 931 mm, most of which is re- ceived during monsoon season from June to September.

Diagnosis Gynacantha chaplini sp. nov. can be easily recognised by the presence of a dark brown trapezium-shaped dorsal marking on the postfrons (Fig. 2a). It can be further distinguished from the other Gynacantha species by the un- marked synthorax, and by the size proportion and shape of the elements of the caudal appendages, i.e., epiproct less than half the length of cerci, apex of the cerci pointed downward (Figs 1a, b, 2c, d).

Figure 3. Stream close to the Khadimnagar Tea Garden near the Khadimnagar National Park, Sylhet, Bangladesh, type locality of Gynacantha chaplini sp. nov. Photo: MKK (10-vii-2017)

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Table 2. Morphological traits of South Asian Gynacantha species (cf. Table 1). Pf: mark on postfrons (T – T-shaped, unm – unmarked); Pt: pterostigma length [mm]; HwL: hind wing length [mm]; FwAx: fore wing antenodal cross-veins; Tr: number of cells in triangle (F – fore wing, H – hind wing); AnL: number of anal loop cells; AbdL: abdomen length [mm]; S1–S3: abdominal segments 1–3 (c – constricted, mc – moderately constricted, nc – not constricted); E/C: length ratio Epiproct/Cerci; Inc: incision on cerci present; Cerc: form of inner cerci (bis – bi- sinuous, sin – sinuous, str – straight); AC: Apex of cerci (1 – dilated, tip directed outward, 2 – dilated, tip directed downward, 3 – dilated, tip pointed downward, 4 – undilated, tip directed outward, 5 – constricted, tip directed outward, 6 – tip directed inward).

Species Pf Pt HwL FwAx Tr AnL AbdL S1–S3 E/C Inc Cerc AC Fw 5; G. albistyla unm – 34–38 17–18 8–10 41–43 mc 1/2 str 1 Hw 4 G. anda­ Fw 5–7; Arrow 3.5–4 42 26 11 45 c 1/3 str 1 manae Hw 5–6 Fw 5; G. arnaudi T 4.5–5.5 42–44 24 – 50–54 – 1/4 + sin 4 Hw 5 G. bain­ Fw 6–7; Arrow 3–4 43–44 23–24 10–12 45 – 2/5 bis 2 briggei Hw 5–6 G. baya­ Fw 6; unm 3 38–40 18–19 10–11 45 c 1/3 str 1 dera Hw 5 Fw 6–7; G. biharica T 3–4 42 24–25 12 45 c <1/2 sin 1 Hw 5–6 G. chaplini Trape– Fw 5 4–5 40.1 19–20 9–12 53.4 c <1/2 str 2 sp. nov. zium Hw 5 Fw 5–7; G. dravida T – 50–51 25–28 13–17 50–51 c 1/3 bis 1 Hw 6 Fw 5; G. incisura T 3.5 45 19–20 8–9 47 c <1/3 + str 4 Hw 5 Fw 5, G. khasiaca T 4–5 45 25–27 8–9 48–49 c >2/3 sin 6 Hw 5 Fw 6; G. millardi unm 3 44 20–22 9–12 46 nc 1/3 sin 1 Hw 5 Fw 6; G. odoneli unm 3 39 18–22 10–11 41 c <1/2 str 1 Hw 5 G. palam­ Fw 5; T – 37–39 17–21 – 41–45 c <1/2 str 5 purica Hw 5 G. sub­ Fw 5–6; T 3–4 42–45 22–24 11–14 44–50 c <1/3 sin 3 interrupta Hw 5–6

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Discussion The male of Gynacantha chaplini sp. nov. can be distinguished from all described males of the other South Asian Gynacantha species by a dark brown trapezium-shaped mark on the postfrons (Table 2). Seven of these species have a T-shaped mark on the postfrons. Four species (G. albistyla, G. odoneli, G. millardi, G. bayadera) have an unmarked postfrons. A dark arrow-shaped mark is present on the postfrons of G. andamanae and G. bainbriggei, and only the crest of the frons is significantly darkened (deep dark reddish-brown) in G. albistyla. An updated key to the males of the South Asian Gynacantha species is given below. Two of the 15 species known only from a female specimen are excluded from the key. They are Gynacantha rammohani Mitra & Lahiri, 1975, from India and Gynacantha apicalis Fraser, 1922, from Pakistan.

Key to males of Gynacantha from South Asia 1a – Small species, hind wing <40 mm ...... 2 1b – Larger species, hind wing >40 mm ...... 3 2a – Postfrons unmarked; epiproct < ½ the length of cerci (Fig. 4a) ...... G. odoneli 2b – Postfrons without T mark; epiproct ½ the length of cerci ... G. albistyla 2c – Postfrons marked with a T ...... G. palampurica 3a – Postfrons marked with a T ...... 4 3b – Postfrons marked otherwise ...... 7 3c – Postfrons unmarked ...... 9 4a – Cerci with a distinct emargination near base ...... 5 4b – Cerci without a distinct emargination near base ...... 6 5a – Apex of cerci pointing downward (Fig. 4b) ...... G. arnaudi 5b – Apex of cerci pointing outward (Fig. 4c) ...... G. incisura 6a – Epiproct > ½ of the length of cerci (Fig. 4d) ...... G. khasiaca 6b – Inner border of cerci sinuous, apical third broadly marked, epiproct > ⅓ but < ½ the length of cerci ...... G. biharica 6c – Inner border of cerci bi-sinuous, epiproct ⅓ the length of cerci (Fig. 4e) ...... G. dravida

Odonatologica 50(1/2) 2021: 95-105 Gynacantha chaplini sp. nov. from Bangladesh 103

6d – Epiproct < ⅓ the length of cerci (Fig. 4f) ...... G. subinterrupta 7a – Postfrons with a trapezium-shaped mark (Fig. 2a) . G. chaplini sp. nov. 7b – Postfrons marked with an arrow ...... 8 8a – Inner border of cerci bi-sinuous; epiproct ²/₅ the length of cerci (Fig. 4g) ...... G. bainbriggei 8b – Inner border of cerci not curved; epiproct ⅓ the length of cerci ...... G. andamanae 9a – Abdominal segment 3 markedly constricted (Fig. 4h) ...... G. bayadera 9b – Abdominal segment 3 not markedly constricted (Fig. 4i) .. G. millardi

Figure 4. A–I – Gynacantha species, male; A, D–G – caudal appendages, dorsal; A – G. odoneli Fraser, 1922; D – G. khasiaca McLachlan, 1896; E – G. dravida Lief- tinck, 1960; F – G. subinterrupta Rambur, 1842; G – G. bainbriggei Fraser, 1922; Figures A, D, F and G redrawn from Fraser (1936); Figure E drawn from the pho- tograph of the Odonata of India website (media code bq098). B, C – Left cercus, dorsal, redrawn from Asahina (1984); B – G. arnaudi Asahina, 1984; C – G. incisura Fraser, 1935; H, I – S1–S3, dorsal; H – G. bayadera Selys, 1891, drawn from the Natural History Museum (London) specimen no NHMUK 011249681; I – G. mil­ lardi Fraser, 1920, drawn from Priyadarshana et al. (2015).

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Acknowledgements I thank Albert Orr, Gunther Theischinger, K.A. Subramanian, and an anony­mous reviewer for their constructive comments. I thank Sukanya Hasan and Zoe Wild for drawing the illustrations. I also thank Payal Barua and Leelaboti Khona for their inspiration and support.

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Theischinger G. & Hawking J.H. 2006. The Yeh W.C. & Veenakumari K. 2000. Descrip- complete field guide to dragonflies of Aus- tion of Gynacantha andamanae, spec. nov. tralia. CSIRO Publishing, Clayton from South Andaman Island, Indian Ocean International Tuhin M.S.H. & Khan M.K 2018. An up- (Anisoptera: Aeshnidae). Journal of Odonatology dated list of Odonata of southwestern 3: 163-167 Bangladesh. Journal of threatened Taxa 10: 12995-13001

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