Cillaeopeplus Sharp

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 : 81-85

32. Genus Cillaeopeplus Sharp in Sharp & Scott, 1908

Cillaeopeplus Sharp in Sharp & Scott, 1908: 436;

Type species: Brachypeplus infimus Sharp, 1878a: 135 (designated by Ford 1958: 341).

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 small to medium (2.5–7.3 mm), rather narrow and subparallelsided, moderately subflattened to slightly convex dorsally and moderately convex ventrally; usually finely and densely punctured integument, with distinct punctured striae on elytra, densely microreticulate to glabrous; usually with dense conspicuous pubescence to sometimes rather short and nearly inconspicuous; head with eyes located basally, with short temples frequently externaly projecting behind eyes, anterior edge of frons subtransversely; antennal grooves rather long, distinctly expressed, convergent posteriorly; pronotum more or less subquadrangular, slightly convex, with rounded anterior and posterior angles, narrowly (sub)explanate along frequently finely serate lateral edges; abdominal laterosternites V and VI somewhat widened posteriorly; prosternum with process not curved or slightly along procoxae, somewhat to strongly widened before transverse to rounded and unbordered apex; all pairs of coxae narrowly separated; posterior edge of metaventrite between coxae usually very narrow angularly excised or somewhat wider and emarginate; tarsi with moderately to narrowly lobed tarsomeres 1–3; female pygidium without serration; male anal sclerite usually scarcely exposed from pygidium and without to extremely finely serrate.

Comparison and notes to composition and diagnostics. Sharp in Sharp & Scott (1908) included in this genus three Hawaiian species ( Cillaeopeplus infimus , C. perkinsi Sharp in Sharp & Scott, 1908 and C. dubius Sharp in Sharp & Scott, 1908) mentioned that this genus is distinct “by the structure of the tarsi, the third joint of which may be said to be without lobes” (Sharp in Sharp & Scott 1908: 135), although this character is scarcely can be used because the level of reduction of the tarsal lobes with setae on below surface of these lobes varies in width within many nitidulid groups, including Cillaeopeplus . The comparatively important characters of this taxon are the distinct head “neck”, basally located eyes and clearly projecting temples behind eyes, expressed serration of lateral pronotal edges, apically widened laterosternites of the exposed abdominal segments. Ford (1958) added two other Hawaiian species to this genus ( Cillaeopeplus swezeyi Ford, 1958 and C. staphyliniformis Ford, 1958 ), one of which differs from four other congeners in the very slightly projecting temples behind eyes (not sharply prominent externally from eyes). Gillogly (1962) described one species assigned to the genus under consideration from Mariana Island ( Micronesia) ( Cillaeopeplus gracilis Gillogly, 1962 ) with the shining integument on dorsum and scarcely projecting temples, although Ewing (2007) erroneously regarded the latter species as a member of the genus Brachypeplus . This species ( C. gracilis ) indeed is rather similar to the Hawaian species and, on the other hand, it is even more similar to the new Australian species (see below) and can be a closer relative to them. Most members of Cillaeopeplus have somewhat emarginate anterior edge and slightly projecting anterior angles of pronotum (but C. swezeyi and C. gracilis are with subtruncate anterior edge and anterior angles not projecting). Finally, Ewing (2007) put Notopeplus reitteri in the genus Cillaeopeplus without any proper comparison and without any argumentation with the congeners of both ( Cillaeopeplus and Notopeplus ), and, therefore, this synonymization needs to be confirmed. According to the original description of Notopeplus reitteri and in contrast to the species of Cillaeopeplus , Notopeplus reitteri has the much more robust body, another type of sculpture of dorsal integument and, particularly, the different structure of the pronotum arcuately narrowing anteriorly from the base and with more raised cilia along its sides (shown in the drawings of Sharp in Sharp & Scott 1908: Pl. XIV, Fig. 2 ).

Futher re-examination of Afro-Malgasy specimens and analysis of characters clarified that at least two generic groups from Africa and Madagascar, which were initially put in the genus Cillaeus , should be regarded separately from the latter and apparently from each other. For one group the name Paracillaeopsis stat. nov. has been already proposed, while the second includes species very similar to those of Cillaeopeplus above mentioned. In general Afro-Malgasy cillaeines are rather variable and their attribution needs to be revised. As a result, there seem to be some groups rather similar to Cillaeopeplus . The species described as members of Cillaeopeplus are possible to divide into two groups which can be treated as subgenera: one of them would be consisted mostly of the members known from Hawaii ( Sharp & Scott 1908; Ford 1958) and characterized by the somewhat smaller and more depressed body, acute temples strongly projecting externally from eyes, slightly exposed labrum without median suture, expressed microsculpture on interspaces between punctures on the upper body sclerites, in general shorter exposed abdominal segments, comparatively smaller mentum, somewhat longer and medially convex plane of the prosternal process with rounded apical edge. At the same time, other known members of Cillaeopeplus beyond Hawaii have the somewhat larger and not strongly depressed body with the more or less smoothed integument on their dorsal body sclerites, temples in most cases not projecting externally from eyes, labrum farther projecting anteriorly and completely divided by the median suture, in general exposed abdominal segments longer, larger mentum, shorter more and regularly subflattened plane of the prosternal process with subtruncate apex. However, many probable members of the Cillaeopeplus of the Indo-Malayan Region (particularly collected in New Guinea) still remain undescribed apparently show even greater diversity of many characters than the diversity of the described ones, and, therefore, a proposal to split Cillaeopeplus into subgenera seems to be not reasonable before a wider revision of this group, as a whole.

This genus is somewhat similar and considered as closely related to the comparatively more generalized genera Brachypeplus and Brittonoma among the Australian cillaeines (see the above key to Australian genera and subgenera). Cillaeopeplus is also rather similar and could be also related to Laferollaeus gen. nov. differing from the latter in the usually wider body, subtriangular head with distinct short “neck” and basally located eyes, subquadrangular and subflattened pronotum with usually subtruncate anterior edge, striate elytra with seriate punctation, abdominal laterosternites V and VI distinctly widened posteriorly, somewhat more widely separated procoxae and metacoxae, prosternal process subrectilinearly widened to subtruncate apex forming distinct lateral angles (not arcuately widened to widely rounded apical angles), markedly wider femora, and also in the not serrate posterior edge of the male anal sclerite. On the other hand, Cillaeopeplus is very distinct from the Australian Matthewsianus gen. nov. (apparently also closely related to Brachypeplus ) in the much narrower body with somewhat convex dorsum; subtriangular head with distinct “neck”; subquadrangular and slightly transverse pronotum with subtruncate anterior edge and gently convex to subtruncate posterior edge (not emarginate at posterior angles); narrowly explanate pronotal and elytral sides; distinctly striate elytra with seriate punctation, ultimate abdominal segment not partly retracted into previous one and not widely truncate at apex, more narrowly separate all pairs of coxae, distinct premesofemoral depressions; narrower and subtriangular tibiae.

This genus can be also compared with the following genera:

– with Allenipeplus but differs from the latter in the somewhat more subparallel-sided and less convex body; subtriangular head with distinct “neck” and eyes basally located; subquadrangular, subdepressed and slightly transverse pronotum with subtruncate anterior edge and gently convex posterior edge; striate elytra with more or less seriate punctation; abdominal laterosternites V and VI distinctly widened posteriorly, ultimate abdominal segment not strongly elongate; strongly widened apex of prosternal process and less distinctly isolated premesocoxal depressions;

– with Cillaeus but differs from the latter in the smaller, narrower, subparallel-sided and less convex body; subtriangular head with distinct short “neck” and eyes basally located, widely subtruncate labrum moderately exposed (not far projecting); subquadrangular, subdepressed and slightly transverse pronotum with subtruncate anterior edge and gently convex posterior edge; distinctly striate elytra with seriate punctation; abdominal laterosternites V and VI distinctly widened posteriorly; subtruncate apex of markedly shorter prosternal process; shorter legs with wider femora and tibiae, and also with comparatively narrow tarsi;

– with Macrostola but differs from the latter in the somewhat more subparallel-sided and less convex body; subtriangular head moderately projecting anteriorly (not strongly), eyes medium-sized and basally located (not very large with longitudinal diameter much greater than half of head length), moderately projecting and subtruncate labrum (not strongly projecting); subquadrangular, subdepressed and slightly transverse pronotum with subtruncate anterior edge and gently convex posterior edge (not with widely rounded anterior and distinct posterior angles); longer and densely striate elytra; abdominal laterosternites V and VI distinctly widened posteriorly and convergent antennal grooves;

– with Paracillaeopsis stat. nov. but differs from the latter in the well exposed and subtruncate labrum, subtriangular head with distinct short “neck” and eyes basally located; subquadrangular, subdepressed and slightly transverse pronotum; exposed abdominal laterosternites distinctly widened posteriorly (not subparallel-sided or slightly widened posteriorly), only slightly depressed sides of exposed tergites, ultimate abdominal segment near transverse (not more or less elongate), strongly widened apex of prosternal process and distinctly isolated premesocoxal depressions;

– with Tokocillaeus but differs from the latter in the not so elongate and somewhat subflattened (less convex) body; head with distinct “neck” and eyes basally located (not at midlength); pronotal sides gently and elytral sides moderately sloping (not steeply sloping); shorter and striate elytra with seriate punctation; abdominal laterosternites V and VI distinctly widened posteriorly (not subparallel-sided or slightly widened posteriorly); ultimate abdominal segment near transverse(not strongly elongate); convergent antennal grooves and less distinctly isolated premesocoxal depressions.

Redescription. Body medium-sized (2.5–7.3 mm long), rather narrow and elongate, subparallel-sided; somewhat subflattened to slightly convex dorsally and ventrally. Integument moderately coarsely to finely and moderately sparsely to densely punctured, interspaces between punctures smooth or smoothly microreticulate to alutaceous; elytra striate and with seriate punctation; body with fine, short and slightly conspicuous to inconspicuous pubescence, although abdomen more markedly pubescent; pronotal and elytral sides shortly and densely ciliate, pronotal apex and base sparsely ciliate.

Head subflattened and subtriangular, widest at base before clear “neck”; with moderately small eyes located anteriorly from short to nearly subtransverse temples, more or less projecting externally from eyes or not. Labrum short, transverse and undivided or moderately long, distinctly divided into lobes by median deep suture and with subtruncate anterior edge. Antennal grooves distinctly outlined and S-shaped convergent. Mentum moderately wide and somewhat widening anteriorly, and with anterior lateral angles rounded and projecting anteriorly. Pregenal process at hypostomal sinus moderately wide and slightly curved. Pronotum mostly subquadrangular and slightly transverse, usually with anterior edge subtruncate, anterior and posterior angles more or less rounded; sides gently sloping to narrowly bordered lateral edge. Scutellar shield rather transverse, subtriangular to subpentagonal, with subangular apex. Elytra frequently about 1.5 × as long as combined width, with subtruncate apices and widely rounded at outer apical angles, leaving last three abdominal segments completely exposed, sides steeply sloping at base and more or less flattened at apex. Abdominal laterosternites V and VI moderately or strongly narrow before or at middle and rather widened posteriorly. Three last tergites medially convex and more or less widely depressed at sides. Male pygidium somewhat wider than long, with widely rounded to subtruncate apex. Female pygidium slightly longer than wide, widely rounded and very finely serrate at apex.

Prosternum medially convex and with subflattened process (not curved along procoxae); process rather widened before subtransverse apex and with lateral angles rounded. All coxae comparatively narrowly separated. Lower surface of mesothorax medially subflattened (not excavate), but at sides with gently isolated depressions for receipt of mesofemora. Metaventrite with a distinct discrimen in posterior three fourths, posterior edge between metacoxae angularly excised. Metepisterna very narrow or subtriangular (somewhat widened anteriorly), with almost straight inner edge. Male and female hypopygidium widely rounded at apex.

Legs comparatively short. Tibiae usually moderately stout, subtriangilar, meso- and metatibiae widely rounded at outer subapical angles, spurs short and rather stout; outer side of meso- and metatibiae with two rows of spines becoming stout at apex. Femora of usual shape, moderately wide and moderately short, with straight to slightly convex anterior and posterior edges. Tarsi with narrowly lobed tarsomeres 1–3, male protarsi slightly wider than others.

Male anal sclerite well exposed from pygidium and with clear serration at apex, widely rounded and not serrate at apex. Aedeagus moderately or heavily sclerotized and of structure characteristic of many cillaeines. Ovipositor moderately sclerotized; valvifer moderately wide; gonocoxites with nearly straight lateral edges, their inner and outer lobes clearly isolated, inner lobes transversely separate at middle; styli located at distance from acuminate apex.

Composition and distribution. Only two species from the Australian Region (QLD) are known. Among recent faunas of other territories there have been found some probable their congeners among сillaeines from New Guinea with surrounding islands and also Sunda Islands. The examination of syntypes of “ Cillaeus ” rastrus (FMNH— “ Guam I., Marianas, Fadang, 30 May”, “Coll. & Pres. By Henry S. Dybas, Lot 2095”, “in dry fibrous fruit stalk of Pandanus”) shows that this species is rather similar to the Australian species of Cillaeopeplus and should be used in new combination: Cillaeopeplus rastrus ( Gillogly, 1962) , comb. nov. ( Cillaeus ). In addition to the abovementioned congeners from Hawaii, Micronesia and Australia, one more congener ( Cillaeopeplus gracilis ) described Gillogly (1962) from Micronesia (Mariana Island). Gillogly (1962). Besides, some species of “ Cillaeus ” described from the Indo-Malayan and Afro-Malgasy regions after revision will be transferred to Cillaeopeplus (see above).

Notes on bionomy. The members of this genus seem to be mostly associated with inhabitance under bark of trees. Ewing (2007) noted that the Hawaiin congeners “are found in dry to mesic forests and are fully winged.”

Figures

FIGURE 2. Adocimus (Belonotus) bartenevi sp. nov., orig. Holotype, male from QLD (“… 11 km W of Bald Hill, Mcllwaith Range…”); A: body, dorsal; B: head and thorax, ventral; C: head, dorsal; D: drawing of anterior part of frons, dorsal; E: lateral side of abdominal segments 5 and 6, dorsal; F: male anal sclerite and spiculum gastrale, ventral; G: tegmen, ventral; H: penis trunk, dorsal; I: proximal part of inner sac with armature. Scale bars: a = 1.0 mm to Fig. A; b = 1.0 mm to figs B–C and E–F; с = 0.25 mm to Figs G–I.