Drepanosticta carmichaeli ( Laidlaw, 1915 )

Phan, Quoc Toan, Yokoi, Naoto, Makbun, Noppadon, Joshi, Shantanu, Subramanian, K. A., Ngo, Quoc Phu & Dow, Rory A., 2021, A review of the Drepanosticta carmichaeli-group, with the description of D. wildermuthi sp. nov. from the Central Highlands of Vietnam (Odonata: Zygoptera: Platystictidae), Zootaxa 5067 (2), pp. 187-210 : 194-198

Drepanosticta carmichaeli ( Laidlaw, 1915)

( Figures 3–4 )

Drepanosticta polychromatica Fraser, 1931 Synonym Nov.

Protosticta carmichaeli: Laidlaw (1915) : Original description, pp. 390–391, Fig. 3 (appendages in lateral view) from “Singla, Darjiling Dist. , 1.500 ft. ”, West Bengal, India.

Drepanosticta carmichaeli: Laidlaw (1917) : pp. 341–342, Fig. 1 (head & thorax), Fig. 4 (terminal segments of male abdomen in dorsal & lateral view), Fig. 5 (wings), plates 14–15; Fraser (1931a): p. 67, Fig. 2d (genital ligula in lateral view); Fraser (1931b): Figs 3 , 4 , Plate 2 (appendages in lateral and dorsal lateral views), pp. 337–338 (description of male and female specimens); Fraser (1933): Fig. 67 (wings), Fig. 68 (appendages in lateral & dorsal view), pp. 142–143; Bhasin (1953): Records from Dehradun and Almora, Uttarakhand, pp. 66; Prasad (1974): Records from Garwhal Hills, Uttarakhand, remarks on variation, pp. 41; Prasad & Singh (1976): Records from Dehradun, notes on variation, pp. 121; Prasad & Singh (1994): Records from Rajaji National Park, Uttarakhand, pp. 195, 202. Kalkman et al. (2020): Distribution in South Asia: Bhutan, India, Nepal, Pakistan, pp. 10; Anonymous (2021): Records and photographs from India.

Drepanosticta polychromatica: Fraser (1931b) : Original description, p. 8; Fraser (1933): pp. 144–145 (description of male specimens); Kalkman et al. (2020): pp. 10, 61.

Specimens examined. 2 ♂♂, 1 ♀, Tarbere river (probably Teesta river , 26.23433 N, 89.0000 E, 1000m), Sakka, Darjeeling, India, 3.vii.1963, Syoziro Asahina leg. ( NMNS) ; 3 ♂♂, 1 ♀, India, Arunachal Pradesh, East Kameng District, Seijosa (26.9585 N, 93.011 E), 28.iv.2003, Krushnamegh Kunte leg. ( NCBS) .

Notes. Kalkman et al. (2020: Note 7 on p. 61) already commented on the probable synonymy of Drepanosticta polychromatica with D. carmichaeli . After examining the type specimen of the former via photographs we can confirm this synonymy as discussed below.

Laidlaw (1915) described Protosticta carmichaeli from two males from Singla in Darjeeling (within present day Darjeeling district in West Bengal), also listing two female specimens from the same location but noting that the “condition of the female specimens is such as to make description impossible” Laidlaw (1915: 390). He stated that the terminal segments of the abdomen are entirely black and also that the dorsal surface of the head and the entire thorax is black (bronzy black dorsally, “underneath dull black”), however the description was made from “spirit specimens, all in poor condition”, pale markings are often difficult or impossible to discern in such specimens. Fig. 3 in Laidlaw (1915) shows cerci with a distinct ventral heel in their apical part in lateral view, no subbasal spur on the paraprocts is mentioned and no such spur is visible in the illustration, but this is just as likely to be an accidental omission of a detail. We do not know the current whereabouts of any part of the type series of D. carmichaeli , from Laidlaw (1915) it is implicit that it was in the Indian Museum. Sheela et al. (2016) do not list the species in their catalogue of the types in the National Zoological Collection of India and it is not listed in the current type database of the NHMUK or by Kimmins (1970). Laidlaw (1917: 340) states that “with a fair number of specimens at hand I have been able to deposit a paratype in the British Museum and in my own collection”, however he had additional material in 1917 (see below) it seems that the “ paratypes ” he refers to were not actually part of the type series and therefore not paratypes in the currently accepted sense. Similarly although Fraser (1933) mentions that he had “ paratypes ” in his collection it is highly doubtful that these specimens were actually paratypes (in fact since the type series only consists of four specimens, since Fraser (1933) uses the plural, it is impossible for all specimens mentioned by Laidlaw (1917) and Fraser (1933) as “ paratypes ” to actually be paratypes). There are three specimens (all male) of D. carmichaeli in NHMUK that clearly came from the Indian Museum (from photographs showing the specimens and labels provided by Benjamin Price on 15.x.2021). Two of these are from the series treated by Laidlaw (1917) and therefore not part of the type series. The third specimen has labels stating “Peshoke Spur, Darjiling Dist”, “H.S. Lister” and “Ind. Mus.” Despite having been in the Indian Museum and originating from Darjeeling the other information does not agree with that given for the type series in Laidlaw (1915). Other specimens in NHMUK of D. carmichaeli have different information. Unfortunately it is likely that the actual type series no longer exists.

Laidlaw (1917) erected the genus Drepanosticta for carmichaeli and, partly working from fresh material in better condition from Kalimpong (collected in 1916) and Pashok (collected in 1915), both in present day West Bengal, close to the type locality (Singla), gave a description and illustrations based on two males with blue bands across the vertex, synthorax “golden-brown” at the sides and becoming “brown-black” ventrally, blue antehumeral stripes, a “pale, silvery blue” stripe on the metepisternum and S8–9 blue dorsally with a blue basal mark dorsally on S10 (see Fig. 4 in plate 14 in Laidlaw 1917). As shown in Laidlaw’s Fig. 1 in plate 14 the pale stripe on the metepisternum runs from the wing bases, where it is broad, and tapers toward the spiracle, just reaching the metakatepisternum. The caption to the same figure states “Unshaded parts of [syn]thorax and prothorax bright blue, doted parts olive-brown” which compared with the figure implies that the pronotum of the specimen illustrated was olive-brown centrally with blue bands to either side (on all three lobes) and the dorsum of the synthorax was olive-brown. This is rather contradictory to what is written in the main text in the same publication, where it is stated that the prothorax “is olive-green dorsally …” rather than olive-brown as in the figure caption. The antehumeral stripes are well defined and complete, but narrower centrally than at either end, in the male illustrated in Fig. 1 in plate 14 in Laidlaw (1917). Although difficult to see, Fig. 4a in plate 14 in Laidlaw (1917) also shows a distinct ventral heel on the cerci in lateral view, but again no subbasal spur is visible on the paraprocts or mentioned in the text. Laidlaw (1917) notes in the captions to plate 14 that Fig. 1 was ”Drawn from spirit specimen in collection of Indian Museum” but no such comment is made on Fig. 4 , so that might have been made from a different specimen.

Fraser (1931b) listed D. carmichaeli from the same locations given by Laidlaw (1917), giving a description and illustrations of the anal appendages. It is not clear if Fraser had additional material from the these to that listed by Laidlaw but the months he lists (April to July) are not identical to those given by Laidlaw (1917: April to June) and the measurements that he gives for the male are also not identical (abdomen 36–37 mm, Hw 23–24 mm but abdomen 36 mm, Hw 24 mm in Laidlaw 1917). Interestingly Fraser (1931b) does not include Darjeeling in the distribution of D. carmichaeli , this omission was presumably accidental but unfortunate, especially given that he described D. polychromatica from Darjeeling in the same paper. Fraser (1931b: 337) states that the antehumeral stripes of the male are “ill-defined” and that S8–10 are blue dorsally and describes “a broad, slightly oblique pale blue stripe traversing the whole length of mesepimeron”. It should be noted that Fraser used mesepimeron to denote what would now be referred to as the mesepimeron plus metepisternum (see Fig. 3 in Fraser 1933) so that the stripe on the mesepimeron he mentions is presumably on the metepisternum with modern terminology (otherwise his description is at odds with any specimen or image purporting to be this species seen by us). Fraser’s (1931b) illustration of the anal appendages of the male does not show a distinct heel on the cerci in lateral view (Fig. III in Plate II), although a weak, rounded heel is visible in the dorsal-lateral view (Fig. IV in Plate II), however many of Fraser’s illustrations from this period are over simplified and cannot be relied upon to accurately show diagnostic characters. The subbasal spur on the paraprocts is mentioned for the first time in Fraser (1931b) but is not visible in the illustrations. Fraser (1933) merely reproduces the text and illustration of the anal appendages of D. carmichaeli from Fraser (1931b), the only addition is Fig. 67 showing a forewing (this is not stated but follows from the counts of Px in the description). We are not aware of anything published after Fraser (1933) that includes information that would add to this discussion except in Prasad & Singh (1976) who report variation in size and wing venation in specimens from Dehradun.

Fraser (1931b) described the male of D. polychromatica from Gopaldhara in Darjeeling, India and noted that it is closely allied with D. carmichaeli . Gopaldhara is about 27 km south of the type locality of D. carmichaeli . The number of specimens available to Fraser is not stated, he does state that the type is in his collection (and therefore should now be in NHMUK) and only gives single measurements rather than ranges for the abdomen and Hw, suggesting that he only had one specimen, however this is not definitive. There is a specimen labelled as D. polychromatica in the type collection at NHMUK, with a label by D.E. Kimmins stating “I believe this to be the type” and a holotype label ( Fig. 4a–c ) but no label by Fraser indicating that it is actually the type, however given the lack of any evidence to the contrary we assume that it is the type and it agrees well in details of wing venation with Fraser’s description.

In the key in Fraser (1931b: 337) D. carmichaeli is distinguished from D. polychromatica by “Pterostigma slightly longer than broad; thorax with ill-defined blue stripes, blackish brown beneath” ( D. carmichaeli ) compared with “Pterostigma squared; thorax with well-defined blue stripes, pale beneath” ( D. polychromatica ). Under D. carmichaeli Fraser (1931b: 338) states that D. carmichaeli is distinguished from D. polychromatica by “its larger size, different character of the thoracic markings, different shape of pterostigma, distal origin of Riv + v [R 4, arising at the subnodus in D. polychromatica but proximal to the subnodus in Fraser’s material of D. carmichaeli ] and longer Cuii [CuP].” Under D. polychromatica Fraser (1931b: 338) states “The sharply defined blue and dark brown stripes on the sides form the best medium for separating these two closely-allied species but in addition it is to be noted that whilst the thorax of D. carmichaeli is lighter than that of D. polychromatica , the abdomen is strikingly darker; the 10 th abdominal segment is blue in the former, unmarked in the latter.” On the anal appendages of D. polychromatica Fraser wrote “shaped similarly to those of D. carmichaeli but the inferiors stouter and the basal spine less pronounced.” No additional information is given in Fraser (1933) and D. polychromatica does not appear to have been recorded since.

As far as the wing venation characters Fraser uses to separate the two species go, R 4 arises at the subnodus in all males in the series from Arunachal Pradesh (which are D. carmichaeli by the characters of color and pattern used by Fraser) examined by us, so this is clearly a variable character. In the same series from Arunachal Pradesh the length of CuP is actually longer than in D. polychromatica , so again this character is non-diagnostic.As noted above Prasad & Singh (1976) already commented on some variation in wing venation. The shape of the pterostigma is variable even in single specimens in the series from Arunachal Pradesh and includes the condition seen in D. polychromatica so this character is also non-diagnostic. This leaves only the coloration of the synthorax and S10. In the series from Arunachal Pradesh the venter of the synthorax is pale near the abdomen but darkens towards the legs, so this character is also variable. The exact length of the pale lateral marking on the synthorax is somewhat variable even in the series from Arunachal Pradesh and variation can be seen in the extent of these stripes in the males identified as D. carmichaeli on Anonymous (2021), the degree of definition of this stripe also appears variable, as does the ground color of the synthorax. The male D. carmichaeli specimen from Darjeeling in Asahina’s collection agrees well in the coloration of the synthorax with the D. polychromatica holotype.

The subbasal spurs on the paraprocts are variably visible in individual specimens of D. carmichaeli , so that the apparent difference noted by Fraser also seem to be merely variation. Fraser does not mention any other differences in the anal appendages of D. polychromatica and D. carmichaeli but of course this does not mean that there are no other differences. The anal appendages of the holotype of D. polychromatica are shown in lateral view in Fig. 4c , those of D. carmichaeli in Fig. 3b, d . Although at first sight there appears to be a difference in the length of the apical downturned part of the cerci between the two, the cerci of the D. polychromatica holotype are crossed over each other, making the apical parts look shorter in lateral view ( Fig. 4c ). Moreover the heel on the cerci is variably developed and even the length of the downturned part of the cerci relative to the rest appears somewhat variable in the series from Arunachal Pradesh, so again these characters are non-diagnostic. This leaves only the color of S10 to separate the two taxa and although S10 is blue dorsally in all specimens of D. carmichaeli seen by us ( Fig. 3b ), there is some variation in its extent and there is no reason to suppose that it is not entirely absent on some individuals. In conclusion there do not appear to be any genuinely diagnostic differences between D. carmichaeli and D. polychromatica and we consider that the latter is a junior synonym of the former.

Distribution. India (Arunachal Pradesh; Sikkim; Uttarakhand; West Bengal), Bhutan, Pakistan and Nepal ( Fig. 13 ).

Figures

FIGURE 1. Drepanosticta annandalei ♂ [a, c, e, g, h, i] & ♀ [b, d, f, j], Bamboo Teri,Andaman Island, India (NZC). (a, b), head & thorax, lateral view; (c), head, dorsal view; (d), synthorax, dorsal view; (e, f), terminal segments of abdomen, lateral view; (g–i) appendages in lateral, dorsal and ventral view; (j), pterostigma, ♀.

FIGURE 2. Drepanosticta brownelli ♂, Nankushan Mountain, China (KPMNH). (a), head and thorax, lateral view; (b), prot- horax, lateral view; (c–e), appendages in oblique dorsal, lateral and ventral view.

FIGURE 3. Features of Drepanosticta carmichaeli ♂ [a–f], Darjeeling, India (NMNS) & ♀ [g–j], Arunachal Pradesh, Seijosa, India (NCBS). (a, g), head and thorax, lateral view; (b), abdominal tip, lateral view; (c, d), appendages in dorsal and lateral view; (e), genital ligula; (f), pterostigma; (h, i), prothorax in lateral & dorsal view; (j), abdominal tip, lateral view.

FIGURE 4. Drepanosticta polychromatica, holotype ♂ (NHMUK). (a), holotype male with labels; (b), head and thorax, lateral view; (c), abdominal tip, lateral view.

FIGURE 5. Drepanosticta emtrai ♂, Ta Thom, Laos (ZCDTU). (a), head and thorax in lateral view; (b), tip of abdomen; (c), genital ligula; (d), pterostigma.

FIGURE 13. Distribution map of Drepanosticta carmichaeli group. D. vietnamica (yellow circle); D. annandalei (red circle); D. brownelli (white circle); D. carmichaeli (red square); D. emtrai (blue square); D. hongkongensis (pink square); D. jurzitzai (red triangle); D. wildermuthi sp. nov. (yellow triangle); D. sumatrana (pink triangle); D. tenella (red diamond).