Aulonochares Giron & Short, 2019

Giron, Jennifer C. & Short, Andrew Edward Z., 2021, The Acidocerinae (Coleoptera, Hydrophilidae): taxonomy, classification, and catalog of species, ZooKeys 1045, pp. 1-236 : 1

Genus Aulonochares Giron & Short, 2019 Figs 1D , 2 , 4 , 11J , 21 , 22A-C

Aulonochares Girón & Short, 2019: 112.

Gender.

Masculine.

Type species.

Aulonochares tubulus Girón & Short, 2019: 120; by original designation.

Diagnosis.

Medium sized beetles, total body length 5.8-7.5 mm. Body shape elongated oval in dorsal view; weakly convex in lateral view (Fig. 21 ). Color orange brown to dark brown; ventral surface covered with rather long golden setae, especially on abdominal ventrites, and more densely so (with shorter setae) on surface of femora. Head subquadrate in dorsal view, seemingly constricted at anterior margin of eyes (Fig. 11J ). Eyes relatively small, separated by distance nearly 6.5 × the maximum width of an eye (Fig. 11J ). Clypeus with lateral margins nearly parallel, slightly convex, with anterior margin only slightly narrower than posterior margin (Fig. 11J ). Labrum fully exposed. Mentum and submentum roughly punctate (Fig. 21C ). Antennae with nine antennomeres, with cupule slightly asymmetrical and round in outline. Maxillary palps long, nearly 1.5 × longer than maximum width of head, with inner and outer margins of maxillary palpomere 2 evenly curved (Fig. 21A ). Pronotum with ground punctation shallow and uniformly sparse. Elytra without sutural striae, with outer margins slightly flared; serial punctures, ground punctures and systematic punctures similar in size, shallowly impressed. Surface of prosternum flat (slightly carinate only along midline of antero-mesal projection of anterior margin). Posterior elevation of mesoventrite simple, without carinae or ridges; anapleural sutures concave, anteriorly converging, anteriorly separated by distance nearly 0.3 × as wide as anterior margin of mesepisternum. Metaventrite densely and uniformly pubescent. Protibiae with spines of anterior row very small and appressed (Fig. 21C ); apical spurs of protibiae very short (not exceeding the length of the first tarsomere) and stout. Hydrofuge pubescence covering most surface of metafemora (Fig. 21C ). Ventral face of tarsomeres 1-4 densely covered by stiff setae. Apex of fifth abdominal ventrite strongly emarginate; emargination fringed by stout setae. Aedeagus tubular (Fig. 22A-C ), somewhat cylindrical, with parameres forming a 5-7 × longer than wide tube; basal piece very short and strongly concave; gonopore reduced, located at apex of median lobe.

Differential diagnosis.

Aulonochares can be easily mistaken with Novochares in the New World, and the two genera can be collected together. The subquadrate shape of the head (Fig. 11J ; as opposed to trapezoid as in Fig. 11G ), the roughly punctate mentum, the long setae composing the ventral pubescence of the abdominal ventrites, ventrally densely setose tarsomeres, along with the tubular shape of the aedeagus (Fig. 22A-C ) are very distinctive and uniquely combined in Aulonochares among Neotropical acidocerines.

Distribution.

Neotropical: Brazil (Amazonas, Roraima), French Guiana, Guyana, Suriname, Venezuela; Fig. 4 .

Natural history.

Specimens of Aulonochares have been collected in densely forested sandy streams and detrital pools in forests along creeks. They seem to prefer habitats with abundant detritus or decaying organic matter. Females of A. tubulus and A. ligulatus have been observed carrying their egg cases underneath their abdomen ( Girón and Short 2019; pers. obs.).

Larvae.

Immature stages are not known for the genus.

Taxonomic history.

Recently described by Girón and Short (2019).

Remarks.

Only three species are known for the genus ( Girón and Short 2019).

Species examined.

Aulonochares lingulatus Girón & Short, A. novoairensis Girón & Short, A. tubulus Girón & Short. Holotypes and paratypes of all three species were available for this study. We have not seen any specimens of the genus from outside the Guiana Shield region of South America.

Selected references.

Girón and Short 2019: original description of the genus and all its currently known species; Short et al. 2021: phylogenetic placement.

Figures

Figure 1. Variation across Acidocerinae, dorsal and lateral views A Colossochares ellipticus B Peltochares sp. C Peltochares conspicuus D Aulonochares tubulus E Helochares sp. F Helochares tristis G Novochares sp. H Helopeltarium ferrugineum I Batochares sp. J Helobata larvalis K Radicitus sp. L Nanosaphes tricolor M Agraphydrus cf. attenuatus N Tobochares luteomargo O Tobochares sulcatus P Quadriops similaris Q Crucisternum ouboteri R Primocerus neutrum S Agraphydrus coomani T Agraphydrus sp. U Globulosis flavus V Crephelochares nitescens.

Figure 2. Phylogeny of the Acidocerinae simplified from Short et al. (2021), indicating the distribution, preferred habitat, and currently described number of species for each genus. For habitat, filled black circles indicate that at least some species of the genus are commonly found in this habitat; light grey circles indicate the genus has been found in this habitat, but is rare or not typical for the group; white circles indicate no species have been recorded for the genus in this habitat.

Figure 4. Known distribution of genera of Acidocerinae: Acidocerus, Agraphydrus, Aulonochares, Batochares, Chasmogenus, Colossochares, and Crephelochares.

Figure 11. Head of miscellaneous Acidocerinae A-D anterolateral view: A Tobochares luteomargo with white arrow pointing to straight anterior margin of eye B Tobochares emarginatus with white arrow pointing to Tobochares canthus emarginating anterior margin of eye C Quadriops politus with white arrow pointing to Tobochares canthus fully dividing the eye in dorsal and ventral faces D Batochares sp. black arrow pointing to transverse carina on labrum E-L dorsal view of head: E Batochares sp. F Helochares tristis G Crephelochares nitescens, H Chasmogenus australis with black arrow pointing to preclypeal membrane I Colossochares ellipticus J Aulonochares tubulus K Peltochares conspicuus L Helobata larvalis.

Figure 21. Habitus of Aulonochares spp. A-C A. tubulus: A dorsal habitus B lateral habitus C ventral habitus D A. lingulatus, dorsal habitus. Scale bar: 5 mm.

Figure 22. Aedeagi of Aulonochares and Batochares spp. A A. tubulus B A. novoairensis C A. lingulatus D B. sp. Scale bars: 0.5 mm.