Lestes decipiens Kirby, 1893

Lestes decipiens Kirby, 1893 , bona species

4. Cambodian findings

Of the above mentioned taxa of Lestes spp. , only L. praemorsus decipiens was hitherto reported from Cambodia, for the first time by Roland et al. (2011), not identified to subspecies, later in many particular publications by the second author (further in the text OEK). Cambodia is an Indochinese country, the flora and fauna of which is still rather poorly studied as compared to the adjacent Thailand and Vietnam. However, for the second decade of XXI century, focused studies of the fauna of Odonata of Cambodia, mostly by OEK, have resulted in 204 species (three of which are still unpublished and seven not identified or described) registered in that country with the number of species expected to approach 300 ( Kosterin 2024). Since about one third of Cambodian species of dragonflies and damselflies had still to be revealed, the first author (further in the text PH) undertook two expeditions to the northeastern and eastern Cambodia in 2022 ( Hopkins 2024) and 2024. During the latter one, L. dorothea was found, which had not been reported for Cambodia before.

On 8 vi 2024, whilst exploring an area of the Seima Forest in Modulkiri Province, Cambodia, PH observed up to 4 males of a Lestes species (241078616 and 243313496). No collecting was made. However, preliminary identification of the photographs and video taken based on the pruinescence of the abdominal tip according to Kompier (2025) resulted in Lestes dorothea ( Figs 2–3 View FIGURE 2 View FIGURE 3 ), a species not previously recorded in Cambodia. They were found in a flooded area adjacent to the N76 road, less than 10 km apart from the border with Vietnam (12.190º N, 106.996 º E). The habitat was within evergreen dipterocarp forest and shaded, although some sunshine reached the forest floor in places. There were a deep area of stagnant water with both muddy margins and rich vegetation and an area of slow flowing flood water emanating from a small stream ( Fig. 4a View FIGURE 4 ).

This finding inspired OEK to reconsider his Cambodian specimens (12 males, 1 female) collected in preceding years and previously identified as Lestes decipiens and available for examination (seven more such specimens had been earlier donated to Naturalis Biodiversity Center, Leiden and so could not be checked). They originated from eight localities in Koh Kong, Preah Sihanouk, Kampot, Stung Treng and Mondulkiri Provinces of Cambodia. For 10 of them that identification was confirmed but one male turned out to be in fact L. dorothea , which is superficially similar to L. decipiens but differs strongly from it by the paraprocts( Fig.5a–d View FIGURE 5 ; note that in this figure, the pruinescence is absent as washed off by acetone). It was collected on 27 vi 2018 in a large open swamp with thick sedge, 15 km NNE of Sen Momorom (12.550º N, 107.258º E) ( Fig. 4b View FIGURE 4 ), designated as locality M 12 in Kosterin (2020a) and also considered in Kosterin (2018) (It should be noted that both papers ( Kosterin 2018; 2020a) unfortunately provided somewhat wrong coordinates (12.5771º N, 107.2587º E) for this place, which comprise an error of 2.8 km to the north). Along with the single male specimen of L. dorothea ( Fig. 5a–d View FIGURE 5 ), two male specimens of the true L. decipiens , were collected. So, both species co-occurred at that site. In his report of Odonata found at that swamp ( Kosterin 2020a), OEK listed L. decipiens (37611012) with the abundance score of 4, which means “abundant (~20–100 [individuals])”. This report was correct, but L. dorothea was missing. This location was also visited by PH on 13 vi 2024, who did not record L. dorothea but did record L. decipiens (241479436). Rather remarkably, PH also recorded Lestes nigriceps Fraser, 1924 at this swamp, without any prior knowledge that OEK had previously visited the place and found this species at exactly the same site in June 2018 ( Kosterin 2018; 2020a).

5. Morphological comparison of L. dorothea and L. decipiens

The photographs of morphological details of the holotype ( Figs 6 View FIGURE 6 , 7a–b View FIGURE 7 ) and allotype ( Figs 7c–d View FIGURE 7 , 8 View FIGURE 8 ) of L. dorothea , and of the lectotype ( Fig. 9 View FIGURE 9 ) and female paralectotype (incorrectly designated as “the allotype ” by Kimmins (1970)) of L. decipiens ( Fig. 10 View FIGURE 10 ), kept in the collection of Natural History Museum, London (BMNH) provided us a reference for the characters of this species.

The labels of the type specimens of L. dorothea ( Figs 6b View FIGURE 6 , 8b View FIGURE 8 ) provided more precise information of the type locality than that presented in the original description ( Fraser 1924), and also included the date. The holotype label says: “S. India: / Coorg, / Mercara. / 17-iv-1923. / Maj. F.C. Fraser.” ( Fig. 6b View FIGURE 6 ), hence Mercara is the species’ type locality, and the allotype label is as follows: “S. India: / Coorg, / Greenfields, Sidapur. / 26-iv-1923. / Maj. F.C. Fraser.” ( Fig. 8b View FIGURE 8 ). The original identification labels “ L. praemorsa dorothea ” treats this taxon in a subspecific level, which seems to be Fraser’s initial, not published opinion.

Kirby (1893) did not indicate the holotype of L. decipiens , so Kimmins (1970) designated one of its male syntypes, that from Mahagany, 20 ix 1891, as its lectotype. At the same time he designated a female syntype from 6 th Milestone, Nilavelli Road, 9 xii 1891, as “ allotype ”. However ICZN does not offer an option of subsequent designations of allotypes after original descriptions.Hence the latter female specimen is just one of the paralectotypes. (Also an allotype does not have any taxonomical value above being one of the paratypes.)

We also analysed two males of L. dorothea from Kerala, which is another Indian state in the southern Western Ghats ( Fig. 11 View FIGURE 11 ).

Since the Cambodian specimens available to us included only one female belonging to this group, preliminarily identified as L. decipiens , we also examined the females of L. dorothea ( Fig. 12 View FIGURE 12 a-e) and L. decipiens ( Fig. 12 View FIGURE 12 f-j) from the neighbouring Thailand and Vietnam, respectively. Their identification to species was proved by their being collected while in tandems with males. In sum, morphological details were examined in the following specimens and can be commented as follows: