Chaloenus Westwood 1861
Creators: name: Reid, C. A. M.
name: Beatson, M.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Chrysomelidae
Chaloenus

description: Chaloenus Westwood 1861: 216
Type species: Chaloenus latifrons Westwood, by subsequent designation (Wilcox 1973)
Diagnostic description (based on Takizawa, 2012, and examination of 12 species). Small to medium sized alticine, length 3–8mm; head deflected at antennal insertions, especially in males, with genae and clypeus elongated; genae long, 0.5–2.0x eye length; male frontoclypeus without pits, setose foveae, tubercles or spines; postantennal calli well-defined, adjacent, convex, triangular to rectangular; antennal insertions close, separated by less than socket diameter; first antennomere greatly elongated, much longer than eye, second short, third elongated; labrum with truncate or convex apical margin; apical maxillary palpomere conical, shorter and narrower than preapical; pronotum strongly transverse, width 1.5– 2 x length, broadest at anterior half (usually at anterior angles); pronotum with or without discal depressions (not sharply defined); anterior pronotal border usually absent; procoxae strongly protruding, adjacent; prosternal process narrow but present between coxae; procoxal cavities closed by insertion of hypomera into apex of prosternal process; elytra non-striate to striate, rarely partially costate; elytra glabrous or with scattered erect setae; epipleuron broad at base (0.15– 2 x elytral width), gradually narrowed, upper and lower margins fusing well before elytral apex; mesoventrite process almost triangular, with truncate apex; metaventrite without posterior lobes between hind coxae; metafemur 1.5– 2 x width mesofemur, with internal folded extensor endosclerite for jumping; tibiae rarely sharply ridged externally, without apical spurs; length of first metatarsomere slightly shorter to slightly longer than 2+3; third tarsomere deeply bilobed; tarsal claws appendiculate with basal lobe large and acute; ventrites not laterally ridged; male last ventrite trilobate, with two slots defining median apical lobe; female last ventrite simple; penis elongate-cylindrical with expanded basal foramen, apex symmetrical.
Notes. The original paper erecting Chaloenus was published in issue ‘IV’ of the Journal of Entomology, dated December, 1861 (Westwood 1861). The statement that Medvedev “erroneously dated it as 1861” (Konstantinov & Prathapan 2008: 391) is therefore incorrect. Furthermore, the genus was originally credited with two species, both new, one described by Westwood and one by Baly. A type species was not clearly designated and the genus was not monotypic, therefore the statement by Wilcox (1973: 656), that C. latifrons Westwood is the type species by monotypy, was erroneous. Ironically, Wilcox's statement constitutes a type species designation in itself (International Code of Zoological Nomenclature 1999, Art. 69.1.1), which is C. latifrons Westwood, by subsequent designation of Wilcox. This was overlooked by Konstantinov & Prathapan (2008), who uneccessarily made the same designation.
Konstantinov & Prathapan (2008) synonymised Priostomus Jacoby, 1884, with Chaloenus. The genus Chaloenus has recently been revised (Takizawa 2012) with these two concepts, Chaloenus and Priostomus, retained as subgenera, separated primarily by antennal proportions.
Chaloenus is one of many genera of the leaf beetle subfamily Galerucinae with greatest diversity on the Sunda Shelf of south-east Asia. There are 42 described species (Takizawa 2012), 36 of which are recorded from Borneo. The new species described below is also Bornean and belongs to the nominate subgenus.
description: Published as part of Reid, C. A. M. & Beatson, M., 2013, Chrysomelid males with enlarged mandibles: three new species and a review of occurrence in the family (Coleoptera: Chrysomelidae), pp. 79-100 in Zootaxa 3619 (1) on pages 80-81, DOI: 10.11646/zootaxa.3619.1.6, http://zenodo.org/record/220769