Dineutus (Cyclous) unidentatus Aube, 1838

Deepa, Jaiswal, Shankar, Shiva, Kumar, Devadoss, Madasamy, Karuthapandi, Jadhav, Shrikant & Sulthana, Rehanuma, 2023, Molecular and Morphological identification of the genus Dineutus MacLeay, 1825 (Coleoptera, Gyrinidae) from Eastern Ghats, India, Journal of Insect Biodiversity and Systematics 9 (3), pp. 499-512 : 505

Dineutus (Cyclous) unidentatus Aube, 1838 ( Figs 2C, 2F, 2J)

Dineutus unidentatus Aube, 1838 , 6:788; Dineutus unidentatus, Regimbart, 1882 , 2:424; Dineutus unidentatus Severin, 1890 , 34:194.

Material examined. India, Odisha, 2♂♂, Shakti Waterfall (18°49'51.96''N, 82°36'0.72''E), 18.i.2022, Leg.: J .

Deepa & S. Shankar, Reg. No. FBRC /ZSI/INS/3341; Andhra Pradesh, 7♂♂, 15♀♀, Relli Lake (17°48'35.28''N, 83°19'45.84''E), 21.xii.2020, Reg. No. FBRC /ZSI/INS/2228; 6♂♂ 12♀♀, Thatipudi reservoir (18°10'42.96''N, 83°12'15.48''E), 26.xii.2019, Leg.: J. Deepa & S. Shankar, Reg. No. FBRC /ZSI/ INS/2271 .

Diagnostic characters ( Figs 2C, 2F, 2J). Body size 5.5–7.0 mm, oval, slender, depressed anteriorly, head black, copper or green in color, punctuated, clypeus bronze, reticulation distinct, antennae black with 6 segments, pronotum black, greenish on sides, lateral margin distinctly raised, elytra black, margins slightly pale, dense, visible punctuation on elytra, epipleural angle extended into straight spine, ventral side ferruginous, metacoxal process truncate, pointed, median lobe and paremere subequal, paramere with dense punctuation.

Distribution. Oriental ( Burma, India [Andhra Pradesh, Bihar, Madhya Pradesh, Kerala, Meghalaya, Odisha, Rajasthan, Tamil Nadu], Indonesia, Malaysia, Sri Lanka, Thailand) ( Vazirani, 1984).

Molecular identification. DNA barcoding is considered accurate for species identification ( Hebert et al. 2003; Iftikhar et al., 2016). A total of 22 sequences were generated, including mitochondrial COI and 16s RNA for the genus Dineutus and resulted in the identification of three species namely D. indicus , D. unidentatus and D. spinosus . Mitochondrial COI genes shows notable genetic distance between the three species Dineutus indicus and D. spinosus 12%, D. indicus and unidentatus 10%, D. spinosus and D. unidentatus 12% ( Table 2). 16S RNA genes shows genetic distance between Dineutus indicus and D. spinosus 4%, D. indicus and unidentatus 5%, D. spinosus and D. unidentatus 5% ( Table 3). Phylogenetic trees constructed for both genes found three lineages corresponding to the three nominal species ( Figs 3A, 3B). Phylogenetic tree of COI gene show two separate clades in which D. indicus in one, and both D. spinosus and D. unidentatus in other clade and also shows Dineutus unidentatus and D. spinosus are closely related when compared with three species.