Copelatus maushomi, Sheth & Ghate & Hájek, 2018

Sheth, Sayali D., Ghate, Hemant V. & Hájek, Jiří, 2018, Copelatus Erichson, 1832 from Maharashtra, India, with description of three new species and notes on other taxa of the genus (Coleoptera: Dytiscidae: Copelatinae), Zootaxa 4459 (2), pp. 235-260 : 244-245

Copelatus maushomi s p. nov.

( Figs 4 , 21–22 )

Type locality. India, Maharashtra, 120 km NE of Mumbai, Igatpuri environment, 19°42.3′N, 73°33.1′E, 600 m a.s.l.

Type material. Holotype ♂ (NMPC), labelled: "INDIA occ. centr. / MAHARASHTRA prov. / 120 km NE of MUMBAI / IGATPURI env., 600m [printed] // INDIA 2002 Expedition / 19°42.17′N, 73°33.06′E / 1. – 12. VIII. 2002 / P.Šípek & M.Fikáček leg. [printed] // HOLOTYPE / COPELATUS / maushomi sp. nov. / S. Sheth et al. det. 2016 [red label, printed]" (NMPC). Paratypes: 4♂, 1♀ same data as holotype (LHCM, NMPC, ZSMG). Each paratype is provided with the respective red printed label.

Description of male holotype. Habitus ( Fig. 4 ) elongate oblong oval, nearly parallel sided; outline not continuous as pronotal posterior corners protrude; broadest in basal third of pronotum; very slightly convex. Dorsal surface matt due to dense striolation.

Coloration. Dorsally almost uniformly testaceous; head slightly darker than pronotum and elytra, infuscate posterior to eyes; pronotum indistinctly infuscate on disc; elytra laterally and apically somewhat paler; appendages testaceous. Ventral part testaceous to brownish.

Head. Moderately broad, ca. 0.6× width of pronotum, almost semicircular. Labrum medially emarginate. Anterior margin of clypeus slightly concave. Antennae with antennomeres slender, club-shaped, antennomere I longest. Eyes emarginate anterolaterally, small, eye width only ca. 0.1× width of head. Reticulation consisting of well impressed polygonal meshes; meshes slightly larger in anterior region. Rather long, longitudinal or oblique strioles present between eyes and on vertex. Punctation double; several large setigerous punctures present in fronto-clypeal depressions, frontal depressions at level of anterior margin of eyes, and in depressions along inner margin of eyes; very fine and sparsely distributed punctures placed among meshes of microreticulation, punctures denser posteriorly.

Pronotum. Transverse, broadest in basal third. Anterior angles acute, posterior angles rectangular. Sides largely and evenly curved, with lateral beading very thin and indistinct. Anterior margin straight, posterior margin sinuate. Surface reticulation consisting of polygonal meshes, similar to that of head, but slightly less impressed. Disc of pronotum completely longitudinally striolate; strioles mostly long, well impressed, rarely confluent; few short, shallow strioles present between long strioles. Punctation double; row of coarse setigerous punctures present along anterior margin, basal margin (except medially), and laterally close to sides; fine punctures placed among meshes of microreticulation. Scutellar shield broadly triangular.

Elytra. Elytral striation consisting of nine complete shallow discal striae; striae almost imperceptible due to dense striolation of elytra. Strioles very long, rarely confluent. Surface reticulation consisting of fine, shallowly impressed isodiametric polygonal meshes. Punctation consisting of setigerous punctures only, few punctures present along elytral striae, but predominantly apically and along lateral margin of elytra; fine punctures, due to dense striolation not perceptible.

Legs. Protibia modified, angled near base, distinctly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1–3 distinctly broadened, with four rows of adhesive setae on their ventral side.

Ventral side. Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex rounded; distinctly bordered laterally; reticulation or punctation absent. Metaventrite with microsculpture consisting of polygonal meshes; punctation imperceptible. Lateral parts of metaventrite ('metasternal wings') tongue-shaped, slender. Metacoxal lines well impressed, incomplete—absent in anterior fourth. Metacoxal plates covered with deep, longitudinal or oblique strioles; reticulation consisting of elongate, longitudinal polygonal meshes. Punctation on metacoxae absent. Metacoxal processes rounded and incised at posterior margin. Abdominal ventrites I–II with longitudinal strioles; ventrites III–IV with oblique strioles laterally, absent medially. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I–II, oblique on ventrite III and transverse on ventrites IV–VI. Punctation consisting of fine punctures medially, and larger and deeper punctures laterally.

Male genitalia. Median lobe in lateral aspect almost evenly curved; narrowing from base to pointed apex; broadest in middle ( Fig. 21 ). A fold present till subapical region. Parameres more or less 'D'-shaped, slightly sinuate on outer margin, apex very narrow and long; apical lobe club-shaped ( Fig. 22 ).

Female. Females do not differ in external morphology from male except for nearly straight, apically less broadened protibia, and slender pro- and mesotarsi without adhesive setae.

Variability. All specimens of the type series are rather uniform and vary only in extent of infuscation of head and pronotum.

Measurements (N=5). TL: 4.6–5.0 mm (holotype: 4.8 mm); Tl-h: 4.2–4.5 mm (holotype: 4.4 mm); MW: 2.0– 2.1 mm (holotype: 2.0 mm).

Differential diagnosis. Based on the presence of nine dorsal striae on the elytra, the new species can be tentatively classified within the Copelatus consors species group sensu Guignot (1961). This group so far contains eighteen species: 11 in the Afrotropical and seven in the Nearctic region ( Nilsson & Hájek 2018).

Copelatus maushomi sp. nov. does not seem to be related to any species of the C. consors group. With small eyes, pronotum distinctly broader than elytra, and elytra with dense striolation, the new species has very unique appearance within all known Copelatus species. The shape of the male median lobe suggests that the species may be related to Indian species of the C. nigrolineatus group— C. deccanensis sp. nov. and C. schuhi .

Etymology. The species is named after the 'maushom'—a local name for the monsoon, indicating that the specimens were collected at the beginning of the monsoon season. The name is a noun in the genitive case.

Collecting circumstances. The specimens were collected in small deep pools in a stony stream below a table mountain ( Fig. 44 ). The place was visited at the beginning of the monsoon. Sudden large amount of water could have brought the specimens to the normal stream from less accessible habitat, e.g. wet gravels on the stream bottom or other interstitial water habitats (M. Fikáček, pers. comm. 2017).

Distribution. The species is so far known only from the type locality ( Fig. 45 ).

Figures

FIGURE 45. Distributional map of Copelatus species in Maharashtra.

FIGURES 1–4. Habitus of Copelatus. 1–2. C. deccanensis sp. nov.: 1. male holotype; 2. male paratype with striolate elytra (Harishchandragad); 3. C. schuhi, male (Lonavala); 4. C. maushomi sp. nov., male holotype.

FIGURES 17–22. Male genitalia of Copelatus. 17–18. C. deccanensis sp. nov.; 19–20. C. schuhi; 21–22. C. maushomi sp. nov. 17, 19, 21. median lobe in lateral view; 18, 20, 22. paramere. Scale bar 0.5 mm.

FIGURES 41–44. Habitat of Copelatus. 41. ephemeral puddle (Tamhini); 42. rock puddle (Harishchandragad); 43. puddle (Tamhini); 44. mountain stream (Igatpuri area; photo M. Fikáček).