Syndicus (s. str.) microphthalmus, Jałoszyński, 2023

Jałoszyński, Paweł, 2023, Two new species of Syndicus in southern India (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5230 (4), pp. 489-495 : 490-492

Syndicus (s. str.) microphthalmus sp. n.

( Figs 1–6 )

Type material studied. Holotype: INDIA: ♁, two labels: “ 27.-29. VIII. 1999 / S-INDIA, Tamil Nadu / Kodaikanal / 18 km → Munnar / 2300 m, leg. Riedel ” [white, handwritten], “ SYNDICUS (s.str.) / microphthalmus m. / P. Jałoszyński, ’23 / HOLOTYPUS” [red, printed] ( MNHW).

Diagnosis. Male: microphthalmous, eyes weakly convex, each only slightly oval, lacking posterior emargination and only as wide as apical width of scape; endophallus with indiscernible vesicular elements, with large and darkly sclerotized central complex and distal tubular portion flanked by elongate, sinuate and distally broadening sclerites.

Description. Body of male ( Fig. 1 ) strongly elongate, strongly convex; pigmentation dark brown, legs, antennae and palps indistinctly lighter, body covered with yellowish setae distinctly lighter than cuticle; BL 3.58 mm.

Head ( Figs 1, 2 ) broadest at eyes, HL 0.63 mm, HW 0.78 mm; tempora in dorsal view nearly 3 times as long as eyes, in anterior half weakly converging posterad, in posterior half strongly, rapidly curved mesad, posteromedian margin of vertex weakly concave posteriorly. Eyes conspicuously small and weakly convex, finely faceted, each indistinctly oval and lacking posterior emargination, as wide as apical width of scape. Frons and vertex confluent and transverse; supraantennal tubercles distinctly elevated, diffuse. Posterior region of frons and median portion of vertex with shallow but distinct small punctures separated by spaces subequal to their diameters. anterior region of frons and sides of vertex with much finer, shallower and sparser punctures; setae sparse, long and suberect, postgenae with thick and sparse bristles. Antennae slender and weakly thickening distad, AnL 1.75 mm, antennomeres 1–7 each distinctly elongate (7 weakly so), 8 barely discernibly elongate, 9 about as long as broad, 10 and 11 together distinctly shorter than 8 and 9 combined.

Pronotum strongly convex, stout, broadest near anterior third, PL 1.20 mm, PW 1.00 mm. Sides strongly rounded in anterior half, posteriorly weakly sinuate, anterior corners not marked, anterior margin strongly arcuate, posterior corners obtuse-angled and blunt, posterior pronotal margin weakly arcuate. Pronotal disc demarcated from short posterior ‘collar’ only by transverse row of two dorsal pairs and two lateral pairs of large, deep and oval pits, lacking posterior constriction. Punctures on disc unevenly distributed, those on sides and near anterior pronotal margin distinct but small and shallow, separated by spaces subequal to diameters of punctures, toward middle punctures becoming sparser and those on median region of pronotal disc are separated by spaces 2–3 times as wide as diameters of punctures. Setae sparse, long and suberect, slightly thicker than those on head; thick bristles present on sides of pronotum.

Elytra together oval, broadest indistinctly in front of middle; EL 1.75 mm, EW 1.23 mm, EI 1.43; humeral calli weakly marked; basal impressions shallow; elytral apices separately rounded. Punctures on entire surface of elytra much denser and slightly larger than those on median region of pronotal disc, separated by spaces 0.5–2 times as wide as diameters of punctures; setae similar to those on pronotum but appear slightly thicker.

Hind wings absent.

Legs slender and long, unmodified; glandular openings on dorsal regions of femoral clava small, barely discernible, situated in subapical regions, dorsal longitudinal groove on each femur running from base to glandular opening, but obliterated in distal femoral region; protibiae straight, mesotibiae weakly curved inwards, metatibiae barely discernibly sinuate.

Aedeagus ( Figs 3–6 ) weakly elongate, AeL 0.58 mm; median lobe in ventral view broadest in submedian region, apex broadly subtrapezoidal; endophallus with darkly sclerotized, symmetrical components: medially situated central complex with two pairs of lateral projections, distally connected with broad tubular structure flanked by elongate, sinuate sclerites; proximal vesicular structures indiscernible; parameres slender, in lateral view weakly and evenly curved, apices lacking setae.

Female. Unknown.

Distribution. Southern India: Tamil Nadu.

Etymology. The adjective microphthalmus refers to the exceptionally small eyes.

Remarks. Syndicus microphthalmus is the first known member of this genus with strongly reduced, small, round and weakly convex eyes; all remaining nominal Syndicus spp. have large, bean-shaped eyes with a distinct posterior emargination and strongly projecting laterally from the outline of the head. It also belongs to a group of likely not closely inter-related species with indiscernible vesicular portion of the endophallus, which in other species of Syndicus s. str. is usually easily observable in the proximal endophallic region. Among Indian species, S. microphthalmus is somewhat similar to S. gibbus Jałoszyński, 2004 . These two species are remarkably largebodied (BL over 3.2 mm) and have conspicuously large, stout pronota. However, the entire prothorax in S. gibbus is extremely enlarged, in lateral view higher than elytra and in dorsal view as wide as elytra, while in S. microphthalmus the elytra are more convex and higher than the prothorax, and the latter is clearly narrower than elytra. The aedeagus of S. microphthalmus is also unique and does not resemble that of any Oriental congeners.

Figures

FIGURES 1‒6. Syndicus (s. str.) microphthalmus sp. n., holotype male. Dorsal habitus (1); head in lateral view (2); aedeagus in ventral (3, 5) and lateral (4, 6) views.