Pelossus indicus, Majumder & Ghate & Chandra, 2022

Majumder, Amitava, Ghate, Hemant V. & Chandra, Kailash, 2022, First report of the genus Pelossus Thomson, 1864 (Cerambycidae: Cerambycinae Pelossini) from India with description of a new species, Zootaxa 5105 (4), pp. 593-599 : 594-598

Pelossus indicus sp. nov

( Figs. 1–2 )

Type material: HOLOTYPE: ♂, ‘ India: Chhattisgarh / Kabirdham / Bhoramdev Wildlife Sanctuary / Sakri River / 22 ° 05’40.9” N and 81 ° 09’52.1” E, Alt. 427m / 30. ix. 2013 / A. Raha & Party Coll. // HOLOTYPE / Pelossus indicus sp. nov. / des. Majumder, Ghate, Chandra 2021’ (red label) (ZSI).

TWO PARATYPES (white locality label, pink label: “ PARATYPE / other data ditto as holotype)

Description.

Measurements (in mm): Holotype, ♂: body length 11 (from vertex to tip of elytra), width 3 (at the base of elytra); elytra length 7; pronotum length 3, width 2; antenna length 20. Small, elongate beetle; body colour dark brown to blackish brown at places (head, pronotum and femora) with fine golden or grey pubescence all over the body.

Head: Sub vertical; frons small, sub squarish, depressed in middle, little raised at apex, warty, impressed with median, shining longitudinal sulcus covered with greyish golden pubescence; clypeus small, brownish, separated from the frons with a depressed triangular impression; mandibles moderately robust; vertex warty, covered with greyish golden pubescence ( Fig. 1 D ); antennal supports distinctly raised with their tips slightly angulated, with prominent median smooth sulcus in between; eyes very large, coarsely facetted, slightly emarginated, occupying major portion of head laterally ( Fig. 1 J ).

Antennae long, almost twice the length of the body, brownish black throughout, with greyish pubescence; segment I (scape) strongly thickened, less pubescent and warty, warts sharp at apex, II gradually thickened in apical region, densely pubescent, nearly half of segment I, III segment almost double in length of I but little shorter than IV, remaining segments nearly equal in length, segments VII onwards thinner ( Figs. 1 A - C ).

Thorax: Prothorax broader than head, slightly longer than broad, brownish black with golden pubescence, pubescence more on disc less on lateral margins; pronotal surface rough, granulated, disc depressed, lateral margin very finely curved with some indistinct, blunt tubercles. Width of prothorax distinctly less than width at humeral angles of elytra ( Figs. 1 A, E ).

Elytra elongate, about two and half times the width at humerus, gradually narrowing towards apex; apex of each elytron individually rounded, densely pubescent; each elytron finely punctured, with very small punctures throughout and few large punctures in basal region, punctures sparse in apical region; overall punctures often obscured by pubescence; basal region of elytra around scutellum slightly elevated; scutellum small, transverse and V shaped, black; one moderately prominent longitudinal ridge or costa, on each side of suture, starting from just behind humerus but falling short of apex; humeral angles rounded ( Fig. 1 F ). Thorax ventrally dark brown to black, glossy due to sparse pubescence; procoxal cavities open, prosternal process very narrow, visible part small, triangular, with broad tip, depressed in middle; mesocoxal cavities open to epimera, mesosternal process triangular, its apical part with shallow channel in middle; metasternum broad, with median sulcus in posterior two third region ( Fig. 1 G ).

Legs of moderate length, distinctly compressed, hind femora not extending to apex of abdomen. All femora strongly clavate, all tibia slender, subequal to femora in length, with usual apical spine; tarsus with first tarsal segment much longer, nearly double in length than that of remaining segments united; claws divaricate ( Fig. 1 B ).

Male genitalia: Median lobe longer than tegmen; apical portion of median lobe much smaller than median struts; apex of median lobe very blunt, rounded. Ring portion of tegmen ‘V-shaped. Paramere lobes of medium length, with broad, rounded tip, very close to each other, almost overlapping, with sparse setae; endophallus long, with pair of laminar sclerites seen in the other species of this genus ( Fig.2 ).

Etymology: The species name indicus is derived from the country of occurrence: India.

Distribution: India; so far known only from type locality: Chhattisgarh; female unknown

Differential diagnosis and discussion: The genus Pelossus Thomson, 1864 was founded on Corethrogaster ruber Thomson, 1858 . The original description of the genus is brief and is in French. The characters of our specimen matched with the original description of the genus as well with some recently described species under Pelossus , as discussed below. These males collected from Chhattisgarh are different from the other known Asian species of the genus in having darker and slender body and with the elytra narrowed towards apex. Therefore, these males are described as a new species under the genus Pelossus and are compared with the other similar species.

Five species of Pelossus are known from Asia, as listed in introduction. The new species Pelossus indicus is significantly different from all these five species in possessing dark brown to blackish brown body colour, as the other species are of lighter colouration; besides colouration, P. indicus sp. nov. also differs from the other Asian species in the shape of prothorax, elytral characters and the structure of the male genitalia.

P. unicolor ( Gressitt, 1951) [type locality W. Lichuan Dist., Hupeh province, China], which is recorded from China and Vietnam, is a smaller species (female holotype, 8 mm length, 2 mm breadth), with body colour reddish brown [as per the original description by Gressitt 1951] and the elytra are without any carinae or costae, so in both these characters it differs from P. indicus sp. nov. Additionally, considering the structure of male genitalia of P. unicolor that was subsequently described and illustrated by Yokoi et al. (2016), based on a Vietnamese specimen, it appears that the lobes of parameres in P. unicolor are of uniform breadth from base to apex while those are club like in P. indicus sp. nov. The species P. kalimantanus Yokoi, Makihara & Noerdjito, 2016 (type locality East Kalimantan, Indonesia) is different in having ochraceous body colour and elytra with dark blackish apical region but these characters are absent in P. indicus sp. nov.; in addition the male genitalia in P. kalimantanus are also different, especially because the lobes of parameres are divergent in this species while those are very close to each other in P. indicus sp. nov.. The species P. wakabayashii Yokoi, Makihara & Noerdjito, 2016 (type locality Kalimantan Timur, Indonesia), differs from P. indicus sp. nov. in possessing testaceous body colour (as against blackish brown in P. indicus sp. nov.) and in having pronotum more rounded at sides; besides the male genitalia in P. wakabayashi are also very different with sinuate median struts and divergent lobes of parameres while the median struts in P. indicus sp. nov. are not sinuous and paramere lobes are very close, not divergent. The species P. maruyamai Niisato, 2017 (type locality Langkawi Is., West Malaysia) is similar in appearance but smaller (8.6 mm) and light brown than P. indicus sp. nov. (11 mm, blackish brown); further in P. maruyamai the elytral costae are indistinct while in P. indicus sp. nov. the costae are distinct; in addition, the median struts are also distinctly different in both the species. In the recently described species, Pelossus philippinensis Vives, 2018 (type locality N. Luzon, Abra Province, Philippines), the body colour is brown, prothorax is evenly rounded at sides, the elytra are parallel sided for most of their length and only narrowed in apical region, possess two costae per elytron, median struts are sinuate, the lobes of the parameres are gently rounded and possess sparse setae ( Vives, 2018) whereas in P. indicus sp. nov. body colour is blackish brown, the prothorax is nearly parallel sided and not evenly rounded, the elytra are narrowed slightly beyond middle and there is a single costa per elytron, the median struts are not sinuate, shape of the tegmen is very different and the lobes of parameres are more broadly rounded. In addition, P. philippinensis appears robust and is a slightly longer species (length 12 mm) as opposed to slender and smaller P. indicus sp. nov. (length 11 mm).

There are many species of Pelossus in the African Region but, as pointed out by Yokoi et al. (2016), the Asian species differ from all those in possessing mesocoxal cavities open, at least narrowly, to epimera. Hence it is not necessary to compare Pelossus indicus sp. nov. with the African species; however, it may be pointed out here that Pelossus costatus ( Adlbauer 2012) [described as Lygrus costatus Adlbauer, 2012 ; length 8.5 to 11 mm, type locality Zambia] appears quite similar in colouration and general structure but here the antennal scape is smooth, as against very rough, and elytra are more parallel sided than those of P. indicus sp. nov. Similarly, P. becki Adlbauer, 2015 (type locality Aethiopia) is also a dark brown species but is also very large at 15 mm (length) while P. similis Adlbauer, 2015 (type locality Zambia) is a smaller (length 7–8 mm), yellow brown species and so both are significantly different from P. indicus sp. nov. (see Adlbauer 2015).

Figures

FIGURE 1. Pelossus indicus sp. nov. holotype, male. A, Dorsal habitus; B, Ventral habitus; C, Lateral habitus; D, Head and frons; E, Pronotum; F, Elytra; G, Coxal cavities and sternum; H, Antennal segments; I, Tarsus and claw; J, Lateral view of head and pronotum.

FIGURE 2. Pelossus indicus sp. nov. holotype, male genitalia. Aedeagus in: A, Ventral; B, Dorsal; and C, Lateral view; D, Tip of median lobe and parameres.