Tricheops Newman
Creators: name: Evans, Brenda
name: Ślipiński, Adam
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Cerambycidae
Tricheops

description: Tricheops Newman
Tricheops Newman, 1838: 171. Type species, by monotypy: Tricheops epipphiger Newman 1838. Ślipiński and Escalona 2016: 308.
Diagnosis. Tricheops and Bardistus are the only genera of Australian Cerambycidae with eyes that form 3 distinct lobes. Tricheops (Figs 1, 2, 3) is distinguished from Bardistus (Fig. 4) by a short dispenser bearing long setae apically in the division of lower eye lobe. Bardistus, in contrast, possess a carina-like dispenser bearing dorsal groove (Fig. 4 C) in the division of the lower eye lobe. Further, Tricheops has the antennal scape longer than antennomere 3 whilst Bardistus has the antennal scape sub-equal to antennomere 3 (Figs 1 A, 2A, 3A, 4A).
Description. Length. Medium sized beetles, 12–22 mm long and body elongate oval (Figs 1 A, 2A, 3A). Head. As long as wide and frontoclypeus moderately inclined and transverse. Gland opening at base of mandible reaching posteriorly into lower eye lobe with dispenser bearing group of setae. Longitudinal groove in front of eye absent and median frontal groove complete. Eyes moderately coarsely facetted and divided into 3 distinct lobes (Figs. 1 D, 2D, 3D). Lower lobes well extended ventrally, but broadly separated (Figs. 1 C, 2C, 3C). Gena in front of eye indistinct and labrum free transverse. Apical labial palpomere fusiform and as long, or slightly longer than penultimate palpomere. Apical maxillary palpomere fusiform and longer than the penultimate palpomere. Mandible pointed apically, mesal edge smooth (Figs 1 C, 2C, 3C). Antennal foramen prominent, widely removed from mandibular articulation (by 2.0 to 2.5 times diameter) and dorsal-most margin approximately level with uppermost level of eye (Figs 1 D, 2D, 3D). Antenna. 11-segmented and filiform. Scape gradually expanded toward apex, rounded apically and about 1.5 times length of antennomere 3. Pedicel about as wide as long. Antennomere 3 simple, antennomeres 4–7 without spines; terminal segment shorter than penultimate (Figs 1 A, 2A, 3A). Prothorax. Pronotum sub quadrate, length 0.9–1.1 times width and wider than head. Pronotum widest at middle, constricted at apex and base and lateral margins with broad pointed tubercle (Figs 1 A, 2A, 3A). Prosternum in front of procoxae 2–2.6 times as long as coxa. Prosternal process very narrow, blade-like and not dilated posteriorly. Procoxal cavities strongly transverse with broad angular gap laterally exposing protochantin and widely open posteriorly. Procoxae conical and projecting beneath level of prosternum (Figs 1 B, 2B, 3B). Pterothorax. Scutellum apically rounded and mesoventrite in front of coxae flat (Figs 1 B, 2B, 3B). Mesocoxal cavity broadly open to mesepimeron and mesotrochantin distinctly exposed flat (Figs 1 B, 2B, 3B). Elytra. Straight and interlocking along suture, base not emarginate laterally and lateral edge of elytron straight or weakly sinuate. Three weakly developed costae present and elytral striae and punctures absent. Elytral apices prominent or spinose (Figs 1 A, 2A, 3A). Legs. Protibial spurs paired. Meso- and metafemora broadest near middle and metafemur very long but not exceeding apex of abdomen. Metatarsomere 1 longer than tarsomeres 2–5 combined. Pretarsal claws widely divergent. Abdomen. Intercoxal process triangular and pointed apically (Figs 1 B, 2B, 3B).
Remarks. The unusual division of a lower eye lobe in Tricheops and Bardistus has been observed since the original descriptions by Newman, but the nature of that division so far has not been apparently investigated. In Bardistus the triangular space entering into the lower eye lobe is filled with raised, gutter-like structure originating at the complex pit at the base of the mandible and ending with setose brush (Fig. 4 C). The analogous structure in Tricheops is limited to a pit near mandibular base and a short elevation ending with brush of long setae (Figs 1 D, 2D, 3D). We believe that the pit is connected to intracranial pocket representing probably outlet of gland reservoir (Švácha and Lawrence 2014), while the gutter like structure and the setose brushes are serving as dispensing structures analogous to these described in stinking longhorn beetles (Syllitus Pascoe and Stenoderus Dejean) by Moore and Brown (1971).
description: Published as part of Evans, Brenda & Ślipiński, Adam, 2016, Review of the genus Tricheops Newman (Coleoptera: Cerambycidae: Cerambycinae) with description of two new species from Western Australia, pp. 569-577 in Zootaxa 4137 (4) on page 570, DOI: 10.11646/zootaxa.4137.4.9, http://zenodo.org/record/258411