Pachycerus barclayi, Meregalli, 2009

Meregalli, Massimo, 2009, Revision of the Indo-African Pachycerus Schoenherr, 1823, with a description of four new species (Coleoptera: Curculionidae: Lixinae), Zoological Journal of the Linnean Society 157 (2), pp. 295-325 : 319-322

PACHYCERUS BARCLAYI SP. NOV.

Type locality: India, Tamil Nadu, Manapparai , 10°35′N, 78°25′E .

Holotype male: India: ‘S. India, Manaparai [= Manapparai, 10°35′N, 78°25′E]/ A. Prebunnatha, Pillai ( BMNH). No collecting date is reported; however, the specimen was found in a drawer containing old collections, apparently referable to the first half of the 20th century or before.

Diagnosis: A Pachycerus of medium size, different from all the other species of the genus, and characterized by the convex body, the rostrum with a furrowed median line, the head between the eyes narrower than the base of the rostrum, the densely granulose pronotum, with a few scattered larger granules, the elytra with slightly convex granulose, nearly bare, intervals, the whitish scales that are bifid nearly from the base on the striae and the ventrites.

Measurements: Body length excluding rostrum: 11.48 mm. Rostrum: length, 2.24 mm; width, 1.18 mm; ratio, 1.89. Pronotum: length, 3.56 mm; width, 4.14 mm; ratio, 0.86. Elytra: length, 7.45 mm; width, 4.96 mm; ratio, 1.50. Ratio of elytral to pronotal length: 2.09.

Description ( Figs 97–107 ): Body oblong, convex, humeri not expanded outwards, integument black, moderately glossy, antennae and tarsi ferruginous, with a sparse vestiture of usually whitish bifid scales ( Figs 97–98 ). Rostrum robust, very deeply sculptured, in lateral view regularly curved, dorsolateral margins convergent from base to apex, very irregularly delimited, at base convergent, extended to frontal part of head, with deep convergent punctures, sometimes fused in short rows, margins of punctures in part raised, median part with a large flat surface, not connected to head, slightly broader forwards, delimited from dorsolateral margins by two irregular, scarcely impressed, broad furrows, joined together in front of head and progressively more superficial above antennal insertion, very densely sculptured; median line with equally sculptured surface, with very irregular punctures, single or in part joined together in short rows, interspaces of punctures forming narrow vermiculate wrinkles, central part with a shallow longitudinal impression; apex flattened, with two divergent, barely distinct furrows, with deep sculpture, delimited apically by a short trifurcate ridge; epistoma subquadrate, not expanded apicad; sides in front of eyes with a dense sculpture, with some larger granules on upper part; pregenae glossy, scarcely punctured; upper margin of scrobes weakly sinuate, directed below anterior margin of eye, which is not reached; inferior margin reaching underside of rostrum a little before base. Underside, in lateral view, downward expanded apicad, with a distinct median carinula. Vestiture composed of sparse whitish or yellowish lanceolate or hair-like scales, simple and scattered on surface, scarcely visible, excepting a more dense vestiture of shorter and larger, mainly bifid scales on longitudinal impression of median plate, forming a narrow white stripe; sides with scarce hair-like scales, slightly longer and larger on pregenae; underside with slender white setae. Scrobes narrow, deep, and curved downwards ( Figs 101–102 ). Antennae robust; scape shorter than funicle, regularly broadened towards apex, and weakly curved forwards; funicle short, thick, segment I subquadrate, segment II barely shorter than segment I, segments III–VII transverse, segments VI and VII slightly larger; club large, nearly as long as funicle, densely hairy ( Fig. 107 ). Head shortly globose, in profile curvature slightly sinuate with respect to base of rostrum; interocular space threequarters as wide as rostrum at base, surface densely and deeply sculptured, with irregular punctures deeper and larger between eyes, and smaller and poorly defined on vertex; eyes large, flat, elliptical, lower margin rounded, upper half and upper margin delimited by a furrow in its anterior part. Vestiture composed of whitish bifid scales, disposed in a median stripe connected anteriorly to stripe on rostrum and reaching apex of vertex, and with dense yellowish hair-like setae in periocular furrow. Pronotum very robust, convex, moderately transverse, base sublinearly prominent towards elytra, at centre not expanded against scutellum, sides very regularly curvilinear, maximum width near base, very moderately converging to apex, apex barely prominent above head, postocular lobes scarcely distinct, with a short fringe of setae; dorsum with a narrow, raised median line, continuous on anterior half, broadened into a flat granule at centre, and interrupted shortly behind the central granule; sides of median line flattened, with few glossy granules, surface punctulate, flattened area broadened in its median part, and narrowed forwards and basad, narrower apicad, vaguely rhomboidal, delimited antero- and posterolaterally by a few very large, glossy, very irregularly shaped granules; dorsolateral surface with dense and irregular round glossy granules, occasionally joined by short ridges; sides with less dense granules irregularly aligned in four longitudinal rows, with a larger flat granule in central position between the second and the third row; lower part of sides with smaller, flat granules, with two larger granules near base; surface among granules dull and punctulate. Vestiture composed of slender bifid whitish scales, connected at a third of their length, with long, narrow teeth, dispersed in the median flattened area, obliquely directed forwards, in a few vague patches among granules on the dorsolateral part, and forming a lateral stripe clearly delimited by the rows of granules, narrowed anteriorly; of much smaller and narrower brown bifid scales, connate at base, and sparsely dispersed below the white lateral stripe; and of simple hair-like, scarcely distinct, light-brownish scales, inserted among granules on the dorso-lateral surface ( Fig. 99 ). Scutellum minute, and barely distinct. Elytra oval, convex, at base as large as pronotum base, sides scarcely curvilinear in basal quarter, indistinctly compressed behind humeri, subrectilinear up to apical quarter, regularly converging at apex, distinctly bulging in dorsolateral view before apex between intervals 4 and 8, and transversely compressed behind bulge; in lateral view moderately and regularly curved, declivity scarcely distinct. Intervals large, glossy, slightly convex, odd intervals broader than even ones and slightly larger than striae, excepting interval 2, as large as interval 3 in basal half; all intervals with obtuse granules, dense and aligned in two rows in basal half, and more scattered, and dispersed in one row towards apex; interspaces among granules rough, punctulate, and duller; intervals 7 and 8 at base fused, slightly raised in a rough plate; striae deep, clearly distinct, with dense round punctures separated by an obtuse granule, sometimes as high as the intervals, and forming a short transverse ridge. Vestiture composed of whitish bifid scales, dispersed in the striae and between the granules of intervals ( Fig. 103 ), more dense on sides and declivity, particularly on striae 9 and 10 near base, and joined to the lateral stripe of pronotum; and of simple or rarely bifid narrower light-brownish scales sparsely placed on intervals; setae indistinct, hair-like, curved against integument, scarcely present on lateral intervals, and not particularly differentiated from scales. Legs relatively slender; femora weakly thickened in median part; tibiae rectilinear, internal side weakly sinuate, with minute granules; tarsi broad, segment II transverse, segment III broadly lobed, and longer than segment II; onychium inserted at basal third of segment III; claws connate up to middle of their length, thick, and barely divergent. Vestiture composed of scattered bifid whitish scales and long setae, semi-erect and denser on internal side of tibiae; underside of segments I–III with complete adhesive pad. Ventrites convex, ventrite I depressed in median part, ventrite II as long as ventrite I in its shorter part; ventrite IV slightly shorter than ventrite III, together as long as ventrite II, ventrite V transverse, and twice as wide as long; surface minutely punctulate, and with a few moderately larger punctures. Vestiture composed of whitish very slender bifid scales, connate near base, and at least five times as long as wide, inserted in the minute punctures, with at least one irregular bare glossy patch on ventrites II and III, in semilateral position, not clearly distinct; and some sparse semi-erect long setae inserted in the slightly larger punctures ( Fig. 104 ). Aedeagus slender, median lobe curved, sides subparallel, and weakly convergent anteriorly; apical lamella short, triangular, and not curved ( Figs 100, 105–106 ).

Etymology: I name this new species, with great pleasure, after my friend Maxwell Barclay, curator of the Coleoptera collections of the BMNH, acknowledging his kindness and assistance in all my studies based on the material preserved at the museum.

Affinities: Pachycerus barclayi sp. nov. is clearly differentiated from all of the other species of the genus, but has some similarities in the form of the pronotum and elytra with P. opimus and P. hippali sp. nov. Several important traits, however, separate P. barclayi sp. nov. from them, namely the head without supraorbital tubercles, the forehead between the eyes narrower than the rostrum at the base, rostrum with a shallow median furrow instead of a raised keel, elytra with intervals not raised, etc. All the other taxa of the genus are even more differentiated from P. barclayi sp. nov. In southern India, only P. sellatus occurs. This is a completely different species: much smaller, with a tubercle above the eyes, the rostrum with sharp median and dorsolateral keels, the pronotum flattened, with a broad rhomboidal median impression, the scales bifid from base, the elytra with scales also covering the intervals, etc.

Distribution ( Fig. 108 ): So far only known from the type specimen, collected at Manapparai, in southern India, in the Tamil region.

Figures

Figure 108. The Indo-African species of Pachycerus. Distribution map. Map taken from Encarta World Atlas 2000 (Microsoft Corporation), refined with Photoshop 7.0.

Figures 97–107. Pachycerus barclayi sp. nov., holotypus: body (97, 98); rostrum (101, 102); pronotum (99); antenna (107); detail of elytral scales (103); ventrites (104); aedeagus (100, 105, 106). Scale bars: 97, 98, 5 mm; 99, 104, 2 mm; 100–102, 105, 107, 1 mm; 106: 0.2 mm.