Maxwelleus Meregalli, 2022

Abstract, Massimo Meregalli, 2022, Maxwelleus, a new genus of Curculionidae from the Himalayas, with two new species (Coleoptera: Curculionidae: Molytinae: Euderini), Zootaxa 5105 (2), pp. 281-288 : 282

Maxwelleus Meregalli gen. n.

http://zoobank.org/ urn:lsid:zoobank.org:act:DBC37C64-DC18-48B3-B13C-74B4DB8B046C

Type species, by present designation: Maxwelleus tibetanus Meregalli sp. n.

The gender is masculine.

DIAGNOSIS. Molytinae: Euderini of large size, body 12.5-13.8 mm long, integument matt, smooth. Rostrum robust, curved, rounded in cross section. Eyes large, flat, with more than 100 ommatidia. Pronotum longer than wide, with a distinct transverse groove or constriction behind apex. Elytra flat on dorsum, lacking highly raised glossy granules or tubercles, striae not impressed, with shallowly impressed, rather distantly spaced minute punctures, odd-numbered intervals with a few narrow, but very evident, transverse patches of yellow scales. Femora untoothed. Claws each with strongly developed broad, flat inner tooth as long as 2/3 claw length. Internal sac of aedeagus lacking sclerites.

DESCRIPTION. Rostrum robust, regularly, distinctly curved in lateral view, almost round in cross section, of same approximate circumference from base to apex, surface smooth, punctured, antennae inserted near apex, scrobes narrow, linear, directed towards lower part of eye, clypeus short, transverse, mandibles three-toothed, labial and maxillary palps 3-segmented. Antennae with 7-segmented funicle, first two antennomeres elongate, 3–6 as long as wide or slightly longer than wide, at least 4–6 moniliform; club oval, first antennomere as long as other two together. Eyes large, oval, flat, with at least 100 ommatidia. Pronotum longer than wide, with deep transverse groove before apex, surface smooth or with large irregular obtuse tubercles on disc, median keel at most distinct in anterior part of disc, apex scarcely prominent above head, narrowly sinuate at middle, ocular lobes moderately developed, with short setae. Apex of prosternum deeply incised medially, median groove of prosternum absent; procoxae globular, punctured, touching internally, placed distant from anterior margin. Scutellum visible, minute. Elytra elongate, sides scarcely widened, only slightly wider than maximum width of pronotum, with 9 complete striae, stria 10 short, joined to 9 before midlength, all striae narrow, not impressed, composed of small shallow, not adjacent punctures, narrower than intervals; surface smooth, intervals flat, or odd-numbered intervals weakly convex, lacking highly raised granules or tubercles, at most with low small granules; mesepimeron broadly triangular, mesanepisternum subquadrate; metepimeron narrowly rectangular, with a row of aligned small punctures, metanepisternum barely visible behind metepimeron. Metathoracic wings absent. Femora slender, moderately thickened, untoothed, at most with minute inner ridge; tibiae narrow, slender, apex with fringe of setae, at least on meso- and metatibiae with obliquely ascending dense fringe of setae; tarsi slender, tarsomere 3 with lobes elongate, barely broader than tarsomere 2, claws each appendiculate, inner tooth strongly developed, broad, flat, as long as 2/3 of claw length. Ventrites smooth, ventrite 1 in front of metacoxa as long as 2, 3 and 4 together as long as 2, 5 semicircular, punctured; metaventral process wide, almost as wide as metacoxal cavity. Aedeagus with dorsum of penis membranous, temones almost as long as penis, internal sac, when not everted, longer than penis with temones, with minute sclerotized speckles, lacking large sclerotized sclerites; tegmen oval, manubrium as long as tegmen, parameroid lobes more or less elongate, strongly developed; sternum VIII subquadrate, external side curved upwards, strongly sclerotized. Female not known.

DISCUSSION. The diagnostic combination of characters distinguishes Maxwelleus from the other Euderini , including various taxa currently in study and not yet described. It differs from all of them by the large size, the very peculiar shape of the pronotum with a transverse groove behind the apex, the absence of a prosternal groove, the smooth, matt integument, lacking high glossy granules or tubercles, the untoothed femora and the strongly developed inner tooth of each tarsal claw.

DERIVATION OF THE NAME. The new genus is named after my colleague and friend Maxwell Barclay, curator of the Coleoptera at the NHMUK, who has always provided indispensable contributions to my research with loans of specimens housed at the NHMUK and continuous assistance.

BIONOMY. The is no information on the labels of the two specimens examined. Considering the large size of the body, the big flat eyes, he smoothness of the integument, it seems likely that, different from most other Euderini , the species of this genus do not live in soil or leaf litter, but are associated with shrubs or trees.