Adocimus Murray, 1864

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 : 15-17

3. Genus Adocimus Murray, 1864

Adocimus Murray, 1864: 310.

Type-species: Adocimus bellus Murray, 1864: 311 ; by monotypy.

Diagnosis. This genus is rather distinct among cillaeines by the characters mentioned in the above key to Australian genera and subgenera. It is characterized by the body medium to comparatively large sized (4.0–11.0 mm), rather narrow to moderately wide and elongate oval, moderately subflattened to slightly convex dorsally and more convex ventrally; usually finely and sparsely punctured integument, with punctured striae on elytra or only with their traces, glabrous or with pubescence frequently not visible without high magnification; head with faceted eyes located basally or rather anteriorly, anterior edge of frons subtransversely truncate or sometimes with one couple of paramedian small teeth in males; antennal grooves short, weakly expressed, arcuately convergent posteriorly; pronotum with more or less reduced lateral border (carina) and frequently turning on lower surface anteriorly (to narrowly explanate at base); abdominal laterosternites V and VI usually narrow and subparallel-sided or only slightly widened posteriorly; prosternum with flat and wide median portion extending on flattened process (not curved along procoxae); process strongly widened before transverse and unbordered apex; all pairs of coxae comparatively widely separated; tarsi with moderately or narrowly lobed tarsomeres 1–3; female pygidium with finely serrate apex; male anal sclerite usually scarcely exposed from pygidium and distinctly serrate along subtruncate or widely rounded apex.

Notes on systematic position. The different type of serration of the posterior edge of the female pygidium and male anal sclerite, convex underside and comparatively subflattened upper body plane, considerably reduced antennal grooves, characteristic features of thoracic sclerites (procoxal cavities closed by rather long process of prohypomera, characteristic prosternal process, distinct premesocoxal depressions etc.) and somewhat reduced vestiture are similar to those features observed in some genera spread in the East Hemisphere, mostly in the insular systems of the Indo-Malayan Region and Australia ( Allenipeplus , Caledomus , Cillaeopeplus , Cillaeus , Laferollaeus gen. nov., Liparopeplus , Ithyphenes , Oniphenes gen. nov., Paracillaeopsis stat. nov. and Xanthopeplus ). Adocimus also is similar to Ithyphenes , taking into consideration the prothoracic sides, partial reduction of antennal grooves and join flat plane of the prosternum and prosternal process. It is also important that a peculiar sexual dimorphism in the anterior part of the frons in Adocimus (Belonotus) bartenevi sp. nov. (see below) demonstrates a transition to the structural modification of the frons in Ithyphenes . The subgenera of Adocimus ( Adocimus s. str. and Belonotus sp. nov.) could be also regarded as separate genera, however, a final taxonomic interpretation of these taxa can be more clearly defined after a further revision of Ithyphenes .

Redescription (taking into consideration undescribed species). Body medium to comparatively large sized (4.0–11.0 mm), rather narrow to moderately wide and elongate oval ( Adocimus s. str.) or subparallel-sided elongate ( Belonotus subgen. nov.); moderately subflattened to slightly convex dorsally and more convex ventrally. Integument usually finely and sparsely punctured, underside in places smoothly microreticulate; elytral punctation seriate or rather reduced to diffuse (sometimes punctation very strongly reduced to absent), elytra distinctly striate ( Belonotus subgen. nov.) or without traces of striae ( Adocimus s. str.); body glabrous or with pubescence not visible without high magnification, at least sides of abdominal laterosternites V and VI and sides of abdominal ventrites sometimes with sparse, short, fine and somewhat conspicuous hairs.

Head slightly convex to subflattened and sharply ( Adocimus s. str.) or gradually narrowed ( Belonotus subgen. nov.) to base, moderately projecting anteriorly; with rather small and extremely finely faceted eyes located basally ( Adocimus s. str.) or rather anteriorly ( Belonotus subgen. nov.); anterior edge of frons subtransversely truncate or sometimes with one couple of paramedian small teeth in males; temples long and not abruptly delimited. Labrum with subtruncate anterior edge and divided by median suture into lobes. Mandibles stout, externally flat and with tridentate or bidentate apices (but not infrequently lower dens very small and scarcely traced). Antennal grooves short, weakly expressed, arcuately convergent posteriorly, with smoothed edges. Mentum very wide and with anterior lateral angles rather projecting anteriorly; pregenal process at hypostomal sinus moderately narrow and slightly curved. Terminal labial and terminal maxillary palpomeres subcylindrical. Antennae with 11 antennomeres, bearing club with three antennomeres and somewhat elongate.

Pronotum slightly transverse, subquadrangular, suboval or somewhat widened anteriorly, flattened or slightly convex on disc and gently sloping at sides, with more or less reduced lateral border (prothoracic carina) and frequently turning on lower surface anteriorly (to narrowly explanate at base); anterior angles with narrowly rounded (subangular) tip ( Belonotus subgen. nov.) or widely arcuately continuing to sides ( Adocimus s. str.); posterior angles usually widely rounded or sometimes subangular; anterior edge very shallowly bi-emarginate and slightly convex at middle and posterior edge gently convex. Scutellar shield transverse, subpentagonal ( Adocimus s. str.) or subtriangular ( Belonotus subgen. nov.). Elytra with truncate apices and widely rounded at outer apical angles, leaving last 3–4 abdominal segments completely exposed, sides steeply sloping and narrowly bordered, lateral carinae not visible or slightly visible from above. Abdominal laterosternites V and VI comparatively narrow and subparallel-sided or only slightly widened posteriorly. Postbasal lines of exposed tergites behind elytral apices sharply expressed and with lateral ends disappearing just behind spiracles or sometimes reaching posterior edge of tergites. Spiracles of three preapical abdominal segments elongate oval. Three terminal tergites medially convex and more or less widely depressed at sides. Male pygidium transverse or slightly elongate, with subtruncate or widely rounded apex and without serration or with slightly expressed serration along posterior edge. Female pygidium transverse or somewhat longer than wide or widely rounded at finely serrate apex.

Prosternum with flat and wide median portion extending on flattened process (not curved along procoxae); process strongly widened before transverse and unbordered apex. All pairs of coxae comparatively widely separated. Mesoventrite medially flattened and not excavate, but at sides of consolidated mesothoracic sclerites distinct isolated premesocoxal depressions. Metaventrite with distinct median suture (discrimen) in posterior part. Metepisterna narrow and subparallel-sided. Male hypopygidium with subtruncate to subemarginate posterior edge. Female hypopygidium very widely rounded to subtruncate at apex.

Legs moderately long. Tibiae moderately to rather stout and subtriangular, usually about as wide as antennal club and with strong spur; protibia slightly compressed ( Belonotus subgen. nov.) or swollen (less dorsoventrally compressed) and with group of short and thick spines at apex ( Adocimus s. str.). Femora moderately ( Belonotus subgen. nov.) or rather wide ( Adocimus s. str.), thick, with wide groove for receipt of tibia and with very convex posterior edge of profemur and very convex anterior edge of meso- and metafemora. Tarsi with moderately or narrowly lobed tarsomeres 1–3, protarsi wider than meso- and metatarsi.

Male anal sclerite usually scarcely exposed from pygidium and distinctly serrate along subtruncate or widely rounded apex. Aedeagus moderately or heavily sclerotized and of structure characteristic of many cillaeines. Ovipositor heavily sclerotized, valvifer rather wide at base, inner and outer lobes of gonocoxites well isolated, short styli located at rather acuminate apex.

Composition. This genus includes two subgenera, Adocimus s. str. with the single (type) described species from New Guinea, and Belonotus subgen. nov. with two species, Adocimus (Belonotus) bartenevi sp. nov. from Australia, and A. (B.) nitidulus ( Grouvelle, 1897) [ Brachypeplus ], comb. nov. (? = modiglianii Grouvelle, 1897 [ Cillaeus ]) from Malaysia (Perak) and Indonesia (Sumatra). There are also some undescribed species of both subgenera from the Australian and Indo-Malayan regions.

Distribution. Taking into consideration undescribed species, Malayan Peninsula and insular systems of the Indo-Malayan Region (mostly Papuan Province) and Australian Region.