Megarthrus narendrani, Cuccodoro, Giulio & Liu, Zhiping, 2016

Cuccodoro, Giulio & Liu, Zhiping, 2016, Megarthrus of southern India and Sri Lanka, with notes on their phylogenetic and biogeographical relationships (Coleoptera: Staphylinidae: Proteininae), Zootaxa 4097 (4), pp. 530-544 : 534-537

Megarthrus narendrani sp. nov.

( figs 4 , 15–30 )

Specimens examined. 85: Holotype, male: INDIA: Tamil Nadu: "Madras, Palni H. [Hills], au dessus de [above] Kodaidanal, 2200m, 12. xi. 1972, leg. Besuchet, Löbl & Mussard, #23 [sifting in degraded forest with Rhododendron ]" (MHNG; accession number MHNG ENTO 00008936). Paratypes, 62: same data as holotype (MHNG, 22 males and 15 females); Palni Hills 16km. E. Kodaikanal, 1400m, 15.xi.1972, leg. Besuchet, Löbl & Mussard #28 [sifting in forest] (MHNG, 2 females); Palni Hills 23km. E. Kodaikanal, 1200m, 16.xi.1972, leg. Besuchet, Löbl & Mussard #29 [sifting in forest, near river] (MHNG, 2 males and 1 female); Palni Hills, Kodaikanal, 2100m, 11.xi.1972, leg. Besuchet, Löbl & Mussard #22 [sifting in forest above town] (MHNG, 1 male and 2 females); Anaimalai Hills, Valparai, 1100m, 20.xi.1972, leg. Besuchet, Löbl & Mussard #39 [sifting in forest with coffee trees] (MHNG, 1 male and 2 females); Anaimalai Hills, 18km N. Valparai, 1250m, 18.xi.1972, leg. Besuchet, Löbl & Mussard #35 [sifting in forest] (MHNG, 1 male); Chambaganoor, leg. Donkier (FMNH, 1 female); Kerala: Palni Hills, 30km E Munnar, 77°16’E 10°08N, 1900m, 24.xi.1972, leg. Boukal & Kejval #4 (MHNG, 1 female; NHMW, 4 females); Cardamon Hills, Muttapatti near Munnar. 1700m, 24.xi.1972, leg. Besuchet, Löbl & Mussard #48 [sifting in forest, at foot of group of arboreal ferns] (MHNG, 1 male and 3 females); Cardamon Hills, Kumily, 1000m, 6.xi.1972, leg. Besuchet, Löbl & Mussard #12b [sifting logs and trunks of dead trees] (MHNG, 1 female); Cardamon Hills, [pass 13 km NE of] Munnar, 1900m, 26.xi.1972, leg. Besuchet, Löbl & Mussard #51 sifting logs and trunks of dead trees] (MHNG, 1 male and 2 females). Additional specimens, 22 (all entirely black due to too long storage in inappropriate preservation fluid before dry mounting): Tamil Nadu, Kodaikanal, 700–1000m, 17.i.1972, leg. R. Mussard (MHNG, 1 male); same data, but 1800m, 8.i.1972, (MHNG, 9 males and 6 females); same data, but 2200m, 10.i.1972 (MHNG, 4 males and 2 females).

Description. Habitus as in fig. 4. Combined length of head, pronotum and elytra = 1.60–1.85 mm; maximal pronotal width = 0.80–1.00 mm. Body and appendages predominantly yellow brown, except darker thoracic ventrites and, occasionally, also abdomen; elytra each with broad blackish transverse subapical spot. Dorsal pubescence fairly uniform, sparser on elytral disc; frontal pubescence parallel, medial setae directed backward; elytral and pronotal setae slightly arcuate, recumbent; metaventral setae becoming longer and denser anteriorly, slightly longer than prosternal setae; pubescence on abdominal tergites IV–VI parallel, uniform; that on sternites IV–VII becoming slightly longer posteromedially, lacking subapical macrosetae. Surface of frons and vertex oblongogranulate; pronotum granulofossulate; anterior portion of prohypomera almost smooth; elytra punctate, coarsely; metaventrite coarsely punctate laterally, smooth medially and posteriorly.

Frons above clypeus forming sharp ridge, the latter carinate; lateral outlines markedly concave to apex truncate; mesal portion of disc weakly convex in lateral view, evenly; entire U-shaped frontal impression shallow. Eyes almost hemispherical, with highest point slightly above level of vertex; supraocular margins sinuate in dorsal view. Temples almost smooth; in dorsal view abruptly angled just behind eyes, then weakly convex. Occipital ridge well marked, darkened; anterolateral portions sinuate, extended from lower eye margins dorsally to nearly third of neck width, then recurved posteroventrally back to upper level of eyes; posterolateral portions connected dorsally with irregular transverse ridge. Antenna (fig. 28) without patches of sensilla; scape gradually expanded, conical, not flattened and without longitudinal ridges; pedicel cylindrical, without longitudinal ridge; short and dense pubescence present on antennomeres 8–11; antennomeres 9–10 symmetrical. Maxillary palpi with palpomere 4 about twice as long as palpomere 3, the latter subcylindrical.

Pronotum (fig. 26) with centre moderately convex in frontal view; disc shallowly depressed along lateral portions of anterior and posterior margins, and deeply depressed along lateral edges, the latter markedly raised anteriorly; medial groove very shallow, weakly arcuate in lateral view; hypomera without discal pit, at level of junction with posterior prosternal margin with short ridge, the latter arcuate outward, anterior portion not reaching half of hypomeral width and posterior portion not reaching middle of hypomeron. Proventrite with shallow posteromedial ridge. Protrochanters without longitudinal ridge. Scutellum with anterior margin of disc straight and lateral margins oblique to broadly convex apex.

Elytra with disc evenly convex, without notable relief except humeral callus obsolete and moderate depression along anterior portion of lateral edge; lateral edge arcuate in dorsal view, markedly carinate, with anterior portion markedly serrate, broadly, serration fading posteriorly; sutural margin slightly arcuate in lateral view; posterior margin arcuate toward obtuse inner apical angle. Metaventrite without foveiform impressions in front of metacoxae. Mesofemora as long as metafemora and longer than mesotibiae, with subbasal oblique ridge; metatibia as long as metafemora and longer than mesotibiae.

Male. Anterior frontal margin conspicuously carinate, carina sinuate. Protarsomeres 1 lacking tenent setae. Metatarsomeres 1 shorter than metatarsomeres 2–4 combined. Mesofemora and mesotrochanters as in fig. 22 . Peglike setae arranged in a single row on mesotibiae ( fig. 21 ); mesotrochanters with 1–3 peg-like setae. Abdominal sternites IV–VI unmodified; tergite VIII with apex as in figs 20 ; sternite VIII as in fig. 19 ; hemitergites IX with lateral lobe reduced, similar to that in fig. 55; sternite IX without subbasal medial protuberance. Aedeagus as in figs 15–18 .

Female. Anterior frontal margin slightly carinate, evenly. Abdominal tergite VIII as in figs 29, 30; sternite VIII as in fig. 27. Genital segment as in figs 23–25; gonocoxal plate without dorsal and ventral medial ridges.

Comparisons and diagnostic notes. Megarthrus narendrani sp. n. shares most characters with M.

bimaculatus and M. nilgiriensis sp. n. (see comparisons and diagnostic notes under M. bimaculatus ), however the conformation of their genitalia are diagnostic. In one hand this new species resembles M. nilgiriensis sp. n. with regard to the ventral outline of the aedeagal ventral wall sinuate in male and the presence of two transverse subbasal sclerites in female genital tergites, but M. narendrani sp. n. has the aedeagal tip truncate (while not in M. nilgiriensis sp. n.) and the female valvifers each with a dorsal apophysis locate near their midlength (instead of at level of basal margin in M. nilgiriensis sp. n.). In the other hand M. narendrani sp. n. share with M. bimaculatus sp. n. the dorsal apophysis of female valvifers located near their midlength, but the latter species has the lateral outlines of the middle portion of the valvifers parallel instead of converging and its female genital tergites also lack subbasal sclerites.

Distribution and natural history. The species occurs in the far South of the Western Ghats (Palni, Anaimalai, and Cardamon Hills), where it was collected mainly sifting forest leaf litter at elevations ranging from 700 to 2200 m a.s.l.

Etymology. The species is named in honour of the Keralan hymenopterist Thekke Kuruppathe Narendran (1944 –2013).

Figures

FIGURES 1 – 5. Megarthrus, habitus, male; M. lanka sp. n. (1), holotype; M. rufomarginatus Cameron (2); M. bimaculatus Fauvel (3); M. narendrani sp. n. (4), holotype; M. nilgiriensis sp. n. (5), holotype. Scale bar = 0.5 mm.

FIGURES 15 – 22. Megarthrus narendrani sp. n., male; aedeagus in ventral (15, 18) and lateral (16, 17) views; abdominal sternite VIII in ventral view (19); apex of abdominal tergite 8 in dorsal view (22); mesotibia (21); mesofemur and mesotrochanter (22). Scale bar = 0.1 mm.

FIGURES 23 – 30. Megarthrus narendrani sp. n.; female genital segment, ventral part in dorsal (23) and lateral (24) views, and dorsal part (25) in ventral view; antenna (28); outline of pronotum (26); female abdominal sternite VIII in dorsal (27); female abdominal tergite 8 in dorsal (29) and lateral (30) views. Scale bar = 0.1 mm.