Brittonoma Kirejtshuk et Kovalev, 2017

Kirejtshuk, Alexander G. & Kovalev, Alexey V., 2022, Monograph on the Cillaeinae (Coleoptera: Nitidulidae) from the Australian Region with comments on the taxonomy of the subfamily, Zootaxa 5103 (1), pp. 1-133 : 77-78

28. Genus Brittonoma Kirejtshuk et Kovalev, 2017

Brittonoma Kirejtshuk et Kovalev, 2017: 449 ;

= Brittonema Kirejtshuk, 2011: 57 , nec Thorne 1967: 101;

Type species: Brittonema mandibulare Kirejtshuk, 2011: 58 ; recent, Australia, Queensland (original designation).

Notes. This genus was erected for two species compared with genera similar to the genus Cillaeus ( Kirejtshuk 2011) in the traditional sense, however, the recent studies established the characters making it possible to consider these genera and Brittonoma mainly as a result of convergent development ( Kirejtshuk & Kovalev 2016, 2017) and, on the other hand, this genus demonstrates some generalized characters common with those in Brachypeplus . Thus, the described members of Brittonoma sensu Kirejtshuk (2011) can be supposed as close relatives to Brachypeplus rather than to other genera similar to Cillaeus . Kirejtshuk & Kovalev (2017) proposed a new generic name but they did not specify the taxonomic acts concerning the species names of members of this generic taxon which should be automatically changed. Therefore, the combination of the generic and species names of this generic taxon first used here with indication by “comb. nov.”

Diagnosis. This genus can be diagnosed after the above key to Australian genera and subgenera and it is distinct from other genera from Australia and surrounding territories in a peculiar set of the characters, including the anterior part of frons simple and with anterior edge (sub)truncate; eyes located behind the midlength or at head base; body subflattened along midline; dorsum never concave (convex to subflattened) and with different sculpture; distance between metacoxae subequal with that between procoxae and comparatively slightly smaller than that between mesocoxae; antennae with rather long antennomeres 2–7 about 2.0 × as long as wide, and elongate antennal club (at least 2.0 × as long as wide, not oval or subcircular); prosternum with simple anterior edge (not projecting anteriorly and not forming a chin piece); pronotum subquadrangular, not arcuately narrowed anteriorly, flattened and with subrectilinear and plainly dilated sides (not explanate along sides), with somewhat convex to subtruncate base and with distinct tip of posterior angles; elytra not or narrowly (sub)explanate at sides and much less 1.5 × as wide together as long; abdominal laterosternites V and VI widened posteriorly (not strongly widened); legs comparatively long and narrow; posterior edge of metaventrite between metacoxae nearly straight; tibiae not dilated and subparallel-sided or subrectilinearly narrowing at apex (slightly subtriangularly widened to apex); protibia without subapical teeth along outer edge; meso- and metatibiae without sharp subapical spines along their outer edge; tarsomeres 1–3 widely lobed.

Comparison. This genus can be compared with the genera characterized by the dorsally subflattened body with the pronotum subquadrate or even widened anteriorly ( Cillaeopeplus , Cillaeus , Ithyphenes and Tokocillaeus ). Indeed, the pronotum clearly widened anteriorly is known only in Brittonoma and Allenipeplus (see above). Brittonoma differs from Cillaeopeplus also in the comparatively shorter head, shorter elytra (less than 2.0 × as long as wide), widely dilated tarsomeres 1 – 3, more or less smoothed integument of dorsum between punctures (at least on head and pronotum), and in the elytra with longitudinal rows of punctures but with weakly traced striae. Brittonoma differs also from Cillaeus and Tokocillaeus in the much narrower base of head, lack of median excision or suture of labrum, markedly shorter elytra with seriate punctation, pubescent dorsum; and from Ithyphenes in the head rather narrowed at base, flattened pronotum, shorter elytra, convex or subflattened pygidium, antennal grooves distinct and convergent posteriorly, narrowly separated coxae in all pairs, moderately to widely lobed tarsomeres 1 – 3, and pubescent dorsum. See also the above key to cillaeine genera and subgenera of Australia and surrounding territories and the detailed diagnosis of Brittonoma (= Brittonema ) in Kirejtshuk (2011).

Composition and distribution. This genus includes only the type species and Brittonoma pygidiatum ( Kirejtshuk 2011) .

Notes on bionomy. Both species of Brittonoma described seem to be associated with palms ( Kirejtshuk 2011).