Merogomphus flavoreductus Sawant, Chandran A.V., Koparde & Kunte, 2025

Merogomphus flavoreductus Sawant, Chandran A.V., Koparde & Kunte sp. nov.

Holotype. 1♂ ( IBC-CD337 ), Hadpid , Sindhudurg District, Maharashtra, India (16.3848° N, 73.6249° E; 80 m a.s.l.), 16.viii.2024, Dattaprasad Sawant leg. GoogleMaps

Paratypes. 1♀ ( IBC-CD347 ) location, collector same as holotype, 4.ix.2024; GoogleMaps 1♀ ( IBC-CD348 ) location, collector same as holotype, 6.ix.2024 GoogleMaps .

Etymology. The specific name flavoreductus is given for the reduced yellow markings on pterothorax and abdomen of the individuals combining two Latin words flavo (=yellow, Latin) and reducta (=reduced, Latin).

Proposed English Name. Dark Longleg. The common English name is given due to reduced yellow markings on black pterothorax and abdomen of the individuals.

Description of holotype male IBC-CD337 ( Figs. 7–8 View FIGURE 7 View FIGURE 8 ). In life, male has greenish yellow markings on black ground colour, which fade post-mortem and become darker.

Head ( Fig. 7a–b, d View FIGURE 7 ). Head black. Labium, labrum, mandibles, clypeus, antefrons black, crest of postfrons has broad pale greenish yellow band, median ocellus creamy yellow, rest black with yellow tinge; antennae brown. Eyes turquoise-green in life, greenish grey post-mortem. Postocular area and occiput black.

Thorax. Prothorax ( Fig. 7b, e View FIGURE 7 ). Black, marked with greenish yellow as follows: horizontally elongated oval yellow spot on middle part of anterior lobe; two spots separated by thin black line on the posterior edge of middle lobe, postero-laterally one triangular spot on each side, one small obscure round spot near anterior margin of middle lobe on each side; a big horizontally elongated oval spot on posterior lobe.

Pterothorax ( Fig. 7c, e–f View FIGURE 7 ). Black, marked with greenish yellow as follows: mesothoracic collar broad, connected at mid-dorsal carina; narrow stripes tapering anteriorly on mesepisternum slightly diverging from mid-dorsal carina, antehumeral spot absent; a broad stripe on mesepimeron; two inconspicuous spots on metepisternum, one at upper end, other in the mid part; metepimeron covered with a large spot, sparing only anterior border; a small obscure spot on mesinfraepisternum and metinfraepisternum each, barely visible in life.

Legs. Black; hindlegs are exceptionally long, each femur of hindleg bears 5–6 prominent spines along with numerous fine spines; rest all legs bear small spines; obscure yellow markings on flexor surface of foreleg femurs.

Wings ( Fig. 7c, g View FIGURE 7 ). Hyaline, very faintly tinted with brown; venation black; Pt elongated rectangular, blackish brown, nervures black, covers 4–5 cells below; Arculus at level of Ax 2–3. Crossveins below subcosta 14 in FW and 11 in HW. Cubito-anal space with one crossvein. Anal triangle three celled with a square-shaped central cell; anal loop absent; discoidal field includes two cell rows in all FW and HW. Ax 15 in left FW, 16 in right FW, 11 in both HW. Px 13 in both FW, 12 in both HW.

Abdomen ( Fig. 7c View FIGURE 7 ). Black, marked with greenish yellow as follows: S1 has a mid-dorsal triangular spot extending anteriorly as a thin line, a trapezoid spot on each postero-lateral side in the lower half; S2 has a mid-dorsal band with two bulges, an irregular spot with anterior projection on each postero-lateral side; auricles greenish yellow with anterior margin black; S3–6 with paired mid-dorsal triangular spots at the anterior end; S3 one triangular spot on anterior end of each lateral side and an additional elongated spot ventro-laterally; mid-dorsal spots of S4–6 at anterior end expand laterally to make band which ends ventro-laterally; S7 anterior half with greenish yellow band enclosing a horizontal narrow black streak interrupted at mid-dorsal point; S8 with small inverted triangular spot at anterior end; S9 with a very small obscure spot at centre of dorsum, a pointed spine on mid-dorsum at the posterior end; S10 black. Antero-basal greenish markings on S3–7 have a small black circular mark on each lateral side.

Accessory genitalia ( Fig. 8a–e View FIGURE 8 ). Anterior hamuli black, short; posterior hamuli black, long, almost straight, bending forwards at apex, apex pointed; Vescia spermalis blackish brown, proximal segment funnel shaped; middle segment broad, with prominent blunt spine on dorsum; distal segment creamy yellow with two short flagella, base of flagella broad, roughly rectangular shaped, tips blunt and transparent.

Caudal appendages ( Figs. 8f–h View FIGURE 8 ). Cerci curved, boomerang-shaped, creamy white, outer margin smooth, broad at base, pointed apex, blackish blue tinge appear post-mortem; lateral spine dark brown, broad and blunt; cerci apex straight without any chiselled margin, tip slightly curled upwards; epiproct black, bean shaped in lateral view, broad at base, pointed at apex, turned upwards.

Measurements. Abdomen without appendages 40; HW 31; total length 54.

Description of paratype female IBC-CD347 ( Figs. 9–10 View FIGURE 9 View FIGURE 10 ). In life, females have bright citron-yellow markings on black ground colour, which become dull post-mortem.

Head ( Fig. 9a–b, d View FIGURE 9 ). Black; head and marking on frons crest similar to male. Eyes bottle green in life, greyish green post-mortem. Postocular area and occiput black.

Thorax. Prothorax ( Fig. 9b, d–e View FIGURE 9 ). Similar to male, except being darker and absence of the obscure spots of middle lobe near anterior margin.

Pterothorax ( Fig. 9e–f View FIGURE 9 ). Similar to male, antehumeral stripes are slightly narrower than that of male.

Legs ( Fig. 9g View FIGURE 9 ). Black; hindlegs very long, each femur of hindleg bears 5–7 prominent spines; rest similar to male.

Wings ( Fig. 10a View FIGURE 10 ). Hyaline; Pt elongated rectangular, blackish brown, covers 4–5 cells below; Ax 16 in both FW, 12 in both HW. Px 12 in both FW, 10–11 in HW.

Abdomen ( Fig. 9c View FIGURE 9 ). Black, marked with citron yellow, markings similar to male except following: S1–2 laterally yellow in lower half, S3 with spindle shaped spot on lateral, S4 with small spot on lateral; S10 with a small irregular spot on dorsum.

Caudal appendages ( Fig. 10b–d View FIGURE 10 ). Cerci short, conical, bluntly pointed, creamy yellow with bluish tinge, almost of same length as S10, inner margin has a bulge near base. Epiproct very small, globular, creamy yellow with bluish tinge. Vulvar scale conical, sharply pointed, notched in the middle.

Measurements. Abdomen without appendages 39; HW 32; total length 50.

Variation in females ( Fig. 11–12 View FIGURE 11 View FIGURE 12 ). IBC-CD 348 female has brighter yellow markings, presumably due to its younger age ( Fig. 11 View FIGURE 11 ). Markings on prothorax, mesinfraepisternum and metinfraepisternum are more prominent. Spots on metepisternum are sharply defined. However, S4 has a very faint yellow spot on the lateral. S10 has a slightly bigger yellow spot on the dorsum. Rest of the characters are similar to IBC-CD347.

Measurements. Abdomen without appendages 40; HW 33; total length 54.

Differential diagnosis. Merogomphus aryanadensis can be readily distinguished from other Indian Merogomphus spp. by the thin band of yellow on crest of frons with a ‘curly bracket-shaped’ incursion of black, mesothoracic collar with a gap in between, shape of the stripe on metepisternum and mid-dorsal extension of the basal ring on S7 ( Fig. 13 View FIGURE 13 ). All other Merogomphus spp. including M. flavoreductus have a broad yellow band on the crest of frons ( Fig. 13g, m, s View FIGURE 13 ). Moreover, males of M. aryanadensis have pointed cerci tips which are parallel to each other, whereas the other three species have cerci tips approaching each other ( Fig. 13d, j, p, v View FIGURE 13 ). Male epiproct of M. aryanadensis is placed slightly higher as compared to the others ( Fig. 13d View FIGURE 13 ). Distal segment of vesica spermalis of M. aryanadensis male ends in two long flagella, whereas remaining three species have short flagella in distal segment of vesica spermalis ( Fig. 13f, l, r, x View FIGURE 13 ). M. aryanadensis has fewer yellow markings on the body as compared to M. longistigma and somewhat similar markings as in M. flavoreductus and M. tamaracherriensis ( Figs. 14–15 View FIGURE 14 View FIGURE 15 ). However, above mentioned characters distinctly separate the new species from latter.

Merogomphus flavoreductus is uniquely characterised by the absence of a middle yellow stripe on the lateral thorax and the lack of a mid-dorsal yellow spot on S3 ( Figs. 13–15 View FIGURE 13 View FIGURE 14 View FIGURE 15 ). Morphologically, M. flavoreductus males are most similar to M. tamaracherriensis , but differ by the absence of a spot on the mid-dorsum of S3, boomerang-shaped cerci, a broader epiproct, a wider base of the flagella in the distal segment of the vesica spermalis, and the presence of small black spots on the greenish-yellow abdominal markings laterally ( Figs. 13–15 View FIGURE 13 View FIGURE 14 View FIGURE 15 ). Merogomphus longistigma differs from M. flavoreductus by the presence of extensive yellow markings and more acutely curved male cerci ( Figs. 14–15 View FIGURE 14 View FIGURE 15 ). Merogomphus aryanadensis has pointed male cerci tips which are parallel to each other ( Fig. 13f, l View FIGURE 13 ). Rest of the differences are mentioned in the earlier paragraph.

Habitat and habits. Merogomphus aryanadensis was first photographed from the type locality in October 2020 near a shaded, seasonal stream approximately one metre wide, that flows into the Karamana River across a private land. At that time, only a single male was observed. It was readily distinguishable from its sympatric congeneric, M. tamaracherriensis , by its smaller size. Upon inspecting the photographs, the parallel cerci tips were recognisable, as were the differences in body markings. In the following years, thorough searches of the locality were hindered by a herd of Asian Elephants that had entered the area from the nearby forest. In August 2024, two males were seen perched on the leaves of Ochlandra reeds, at a height of 0.5 metre, on the banks of the same stream. When disturbed, they ascended into the foliage, reaching approximately three metres, and returned to their original positions after 30 minutes. These individuals were collected as holotype and paratype for this study ( Fig. 16a View FIGURE 16 ). The female paratype was collected from a more open habitat, perched on a shrub near an irrigation canal, at a distance of about 10 metres from the stream ( Fig. 16b View FIGURE 16 ). Other odonate species seen along with M. aryanadensis were Hylaeothemis apicalis Fraser, 1924 , Vestalis submontana Fraser, 1934 , Orthetrum chrysis (Selys, 1891) , Caconeura risi ( Fraser, 1931) , and Idionyx gomantakensis Subramanian, Rangnekar & Naik, 2013 .

Merogomphus flavoreductus was initially observed in October 2021 at its type locality in Hadpid village, Sindhudurg District ( Fig. 16c View FIGURE 16 ). Due to morphological similarities with M. tamaracherriensis , it was misidentified. Since then, M. flavoreductus has been consistently observed at the same stream from August through October. This stream in Hadpid village features a seasonal water flow over a rocky bed, located in the low-altitude Konkan region. It is surrounded by cashew plantations and natural forest, with its northern boundary adjacent to a State Highway. Observations indicate that M. flavoreductus predominantly occupies a 200-metre stretch where males are typically seen basking on rocks and leaves, while females remain slightly away from the water, occasionally approaching the stream for oviposition ( Fig. 16d View FIGURE 16 ). The stream has a small weir dam where M. flavoreductus shares the habitat with Disparoneura quadrimaculata ( Rambur, 1842) , Burmagomphus chaukulensis Joshi, Ogale & Sawant, 2022 , Gomphidia kodaguensis Fraser, 1923 and M. souteri during the late monsoon ( Fig. 17b View FIGURE 17 ).

Distribution ( Fig. 18 View FIGURE 18 ). Merogomphus aryanadensis is presently known only from the type locality ( Fig. 18 View FIGURE 18 ). It is likely to inhabit similar environments within the Agasthyamalai landscape.

Merogomphus flavoreductus is also known only from the type locality in Sindhudurg District ( Fig. 18 View FIGURE 18 ). However, similar individuals were observed by DS in other locations from Devgad , Kankavli and Sawantwadi talukas of Sindhudurg District . Close observation of body markings, caudal appendages and genitalia would be helpful to confirm the identity. Consequently , the potential distribution range of M. flavoreductus may extend from the low-altitude regions of Ratnagiri District in Maharashtra to the Uttara Kannada District in Karnataka State .

Phylogeny ( Fig. 19 View FIGURE 19 ). Genetic analysis revealed that M. aryanadensis and M. flavoreductus differed from M. tamaracherriensis by 9.96% and 4.98% respectively in the COI gene compared. The phylogenetic tree ( Fig. 19 View FIGURE 19 ) illustrates that the newly described species are nested within the Merogomphus clade, however, nodal support values were weak.