Drepanosticta annandalei Fraser, 1924

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 : 190-192

Drepanosticta annandalei Fraser, 1924

( Figure 1a–j )

Drepanosticta annandalei: Fraser (1924) : Original description, pp. 412–413, Fig. 12 (terminal segments of abdomen including appendages); Fraser (1931b): Fig. 4 (appendages in lateral view), Plate 1; Fraser (1933): pp. 148–149, Fig. 70 (appendages in lateral view).

Drepanosticta? annandalei: Chhotani et al. (1983) : Record of two females from South Andamans, p. 474, Figs 1–2 (wings venation).

Specimens examined. 2 ♂♂, Moriss Dera (12.5523 N, 92.96802 E, altitude 32 m), Middle Andaman Island, India, 09.ix.2017, Pichai Santhakumar leg. ( NZC) ; 2 ♂♂, same location and collector, 13.iv.2018 ; 1 ♂, 2 ♀♀, Bamboo Teri (11.720 N, 92.656 E, altitude 28 m), Ferrargunj, South Andaman Island, India, 12.xii.2013, Gurusamy Srinivasan leg. ( NZC); all specimens have been examined by K.A. Subramanian .

Notes. Fraser (1924) described D. annandalei from one adult male and a teneral male and female from Mount Harriet, South Andaman Island. An illustration ( Fig. 12 in plate 24) of the male anal appendages in lateral view was provided. On the separation of D. annandalei from D. carmichaeli Fraser (1924: 413) merely states that it is distinguished by “its simple black and white colouring”. However it is clear from the description in Fraser (1924) that the male lacks antehumeral stripes and that abdominal S9–10 are entirely black, which also separates the two species. Moreover it is implicit in Fraser’s description that the pale markings on S8 are white (or whitish), not blue as in D. carmichaeli . The holotype of D. annandalei may no longer exist, according to Kimmins (1966) it was in the Indian Museum. However according to a footnote in the appendix to Kimmins (1966: 223) the entomological collections of the Indian Museum were later transferred to the Zoological Survey of India “but enquiry revealed that most of these types could not be traced, possibly lost by flood damage during wartime storage.” Sheela et al. (2016) do not list the species in their catalogue of the types in the National Zoological Collection of India. The recently collected material from South and Middle Andaman Island reported here generally agrees with Fraser’s description, although the sides of the synthorax are darker than it suggests (presumably this is due to variation) the markings of the terminal abdominal segments are in good agreement.

Although Fraser’s illustration of the male anal appendages may not inspire much confidence, when compared against Fig. 1g –i here it is actually fairly accurate. The anal appendages provide additional characters to separate D. annandalei from D. carmichaeli , the cerci viewed laterally have a more robust build than those of D. carmichaeli and have a strongly petiolate appearance at the midpoint with the apical part broadly expanded ventrally and lacking a distinct ventral heel, while the paraprocts are more robust, lack subbasal spurs and have rounded apices with a slight inward hook in ventral view ( Fig. 1g –i ).

Drepanosticta annandalei is also distinguished easily from all other species in the D. carmichaeli -group excepted D. sumatrana by S9–10 largely black as opposed to having at least some pale coloration dorsally on one or both of these segments in the remaining species of the group. Fraser (1924) notes for the synthorax that in the type “the middorsal carina and upper part of humeral suture” were paler than the rest, as noted above the paler area at the mesopleural suture is visible in the recently collected material and the subtriangular area defined by and including the bifurcated section of the middorsal carina behind the mesostigmal plates is pale; this later is an unusual character in the group.

It is worthwhile to note here, in order to prevent any future confusion, that in the type collection of NHMUK there is a specimen labelled as Drepanosticta annandalei . However this specimen is not Fraser’s D. annandalei , it originates from Jalor in Peninsular Thailand and the name on the labels is an unrealized manuscript name of Laidlaw’s. Laidlaw wrote about this specimen on two occasions, in 1907 ( Laidlaw & Förster 1907) as Platysticta quadrata and later ( Laidlaw 1931) as Drepanosticta sp. , stating that “I do not care to name this species …”. The specimen concerned is actually allied to D. hamadryas Laidlaw, 1931 , possessing a “distinct beard-like brush” on the cerci ( Laidlaw 1931: 188), although at some point after Laidlaw wrote the terminal part of the abdomen including the anal appendages was lost.

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

FIGURE 12. Drepanosticta wildermuthi sp. nov., holotype ♂. Appendages in (a), dorsal view, (b), lateral view & (c), ventral view; (d), genital ligula.

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).