Coelometopon dedzae, Bilton, 2023

Bilton, David T., 2023, New species and new records of minute moss beetles from East Africa (Coleoptera: Hydraenidae), Acta Entomologica Musei Nationalis Pragae 63 (1), pp. 103-110 : 104-106

Coelometopon dedzae sp. nov.

( Figs 1–2 , 4 )

Type locality. Malawi, Mount Dedza, 14°21′42.3″S 34°10′50.0″E, 2030 m.

Type material. HOLOTYPE: J, labelled: “ MALAWI: Mt. Dedza / Dedza env., 2030 m / S14°21’42.3’’ E34°10’50.0’’ / 28.XI.2018, P.Hlaváč lgt.” ( NMPC) with red holotype label . PARATYPES: 1 J 2 ♀♀, same data as Holotype and red paratype label ( NMPC).

Description. Male. Colour. Dorsum ( Fig. 1A ) dark brown to black, legs dark to reddish brown. Maxillary palpi yellowish brown.Antennal club black, stem segments paler yellowish brown. Venter brown to dark brown.

Head broadly triangular, broadest at posterior margin of eyes and narrowing to labral apex. Eyes strongly raised, protruding, and occupying approximately 1/3 of side margin of head. Labrum set beneath margin of clypeus, transverse, with semicircular apicomedian emargination. Anterior and lateral margins evenly rounded, strongly raised and inflexed anterodorsally, with dense erect setae, longer laterally. Clypeus with front angles produced and raised, particularly laterally; front margin arcuate, with stout recurved yellow setae. Dorsal surface dull, granulate, with scattered, curved, yellow setae. Frontoclypeal suture arcuate, weakly impressed. Frons and vertex shining, with dense, strongly raised large granules, particularly interior to compound eyes; with very sparse, curved, yellow setae; setae stouter longer and much denser in front of and around interior margins of eyes. Ocelli indistinct, resembling granules, in posterior part of vertex.

Pronotum transverse, cordiform, broadest at middle. Sides obtusely produced at widest part, narrowing strongly to protruding front angles, and weakly emarginated in front of and behind middle. Posterior angles obtuse. Anterior margin broadly sinuate in middle half, then strongly curved forwards to front angles; posterior margin sinuate around acuminate middle. Median longitudinal furrow of disc moderate, somewhat interrupted in middle; deeper anteriorly and posteriorly, with large, sparse granules in deeper areas. Anterior admedian fovea shallow, deeper anterolaterally and here granulate. Posterior admedian fovea deeper than anterior, with large granules. Anterior adlateral fovea shallow and open laterally, granulate; posterior adlateral fovea deeper, opening laterally to pronotal margin, granulate. Dorsal surface of pronotum shining, without microreticulation, granules restricted to setose ridges between foveal areas.

Elytra elongate, widest approximately in middle, where pseudepipleuron formed from 8 th interval is broadest. Sides almost parallel-sided behind this widest point, weakly narrowing to posterior 1/5, and then strongly rounded to conjointly weakly emarginated apex. Sides of elytra granulate, granules spaced 0.5–1 granule’s width apart, and bearing long, posteriorly recurved, yellow setae. Elytra shining, with some intervals bearing low costae, all costae with rows of long, golden posteriorly recurved setae. Costae most strongly raised on intervals 2 and 4; less so on intervals 5 and 6. Second elytral interval costate in 3 sections. Interval 4 costate in 4 sections. Costae lower posteriorly, but row of setae reaching elytral apex. Interval 5 with setae below shoulder and between costae 2 and 3 of interval 4, overlapping with these costae somewhat. Interval 6 with two weak costae. Interval 7 raised from just behind shoulder to just before apical narrowing of elytra, with row of shorter, yellow, recumbent. Intervals 1 and 3 flat; 3 with short row of similar granules and setae just behind middle.

Venter. Mentum transverse, produced into blunt process apicomedially and with broad, shallow trapezoidal depressions posteriorly either side of midline; lateral margins broadly raised. Shining, with very weak, almost obsolete remnants of microreticulation outside depressions; with stout, erect setae at front angles, along raised margins and posteriorly around depressions. Submentum triangular, shining, without microreticulation; with stout, erect setae as mentum. Prosternum with very low median ridge anterior to procoxae; dull, with scale-like vestiture. Pronotal hypomera very broad, dull, with granulate reticulation and stout, recumbent outwardly-directed setae. Elytral epipleura and pseudepipleura dull; pseudepipleura broad, especially around anterior 1/3, but continued to close to apex. Epipleura continued to apex, but narrowing in posterior 1/4; surface minutely granulate, with a row of shallow depressions. Pseudepipleura granulate, with row of stout, semi-erect setae close to outer margin of epipleura. Mesoventrite dull, granulate, with microscopic scale-like vestiture; raised into small projection between mesocoxae. Metaventrite shining in centre, dull at sides, where surface is minutely reticulate. With shallow elongately oval central depression occupying posterior half of ventrite; depression staggered, deeper in centre. Area around and in front of depression with sparse, shallow, medium punctures, each bearing a long, stout decumbent to recumbent seta. Dull sides of metaventrite with sparse but very coarse, shallow punctures, bearing similar setae. Anterior margins of metaventrite with raised, narrow, arcuate carinae, fringing mesocoxae; centre below posterior junction of mesocoxae with shallow depression in shape of inverted V. Posterior edges of metaventrite, immediately in front of metacoxae, with scale-like vestiture.Abdominal ventrite 1 with strong, curved carina behind each coxa. Abdominal ventrites 1–6 weakly shining, with weak granulate microreticulation; surface increasingly rugose towards margins. Ventrites 1–5 each with 2 irregular transverse rows of punctures bearing decumbent setae. Ventrite 6 with rugose punctures and setae in lateral 0.3s; shining centrally and here with characteristic scale-like reticulation, isodiametric anteriorly and elongate posteriorly.

Aedeagus ( Fig 2A ) robust, main piece broadening apically in ventral and dorsal views. Complex in structure; membranous process minutely spinose, large, expandable; parameres sinuate, joined near base of main piece, reaching proximal part of expanded apical portion of main piece, tipped with long, straight setae; main piece with complex internal sclerotizations, including an internal sclerotised plate occupying the entire lumen and supplied with musculature proximally – presumably constituting part of a pumping mechanism.

Female. Largely as males; last tergite rounded, edges with short, stout, truncate, flattened spines.

Variation. Some variation in degree of granulation of pronotal depressions between specimens.

Measurements. Holotype BL = 2.70 mm; EL = 1.60; EW = 1.15 mm. Paratype male BL = 2.65 mm; EL = 1.60; EW = 1.20 mm. Paratype females BL = 2.60–2.70 mm; EL = 1.15–1.65 mm; EW = 1.15–1.20 mm.

Differential diagnosis. A member of the leleupi group of Coelometopon (see PERKINS 2005), which includes four described East African species: C. cavifrons Janssens, 1972 , C. kilimanjaro Perkins, 2005 , C. leleupi Janssens, 1972 and C. madidum Janssens, 1972 . It shares with these species a relatively large size (2.60–2.70 mm), a short labrum, mostly hidden under the clypeus, wide lateral depressions on the pronotum and details of aedeagal anatomy. The new species would key to C. cavifrons in PERKINS (2005), a species known from the Uluguru Mountains of Tanzania. It can most easily be distinguished from C. cavifrons by the uniformly dark coloration and the anatomy of the aedeagus.

Etymology. Named after the type locality. The specific epithet is a noun in the genitive case.

Distribution and ecology. Only known from the type locality, an isolated massif in central Malawi which rises 2198 m and supports remnant patches of native evergreen forest close to its summit ( Fig. 4 ). No ecological data on the specimens, but likely sampled from or near madicolous habitats, given the known ecology of members of this genus.

Figures

Fig. 1. Malawi Hydraenidae, habitus. A – Coelometopon dedzae sp. nov.; B – Hydraena mulanje sp. nov.; C – Ochthebius erinaceus sp. nov.

Fig. 2. Malawi Hydraenidae, aedeagus, lateral and ventral views. A – Coelometopon dedzae sp. nov.; B – Hydraena mulanje sp. nov.; C – Ochthebius erinaceus sp. nov.

Fig. 4. Distribution map for taxa covered in this paper. Red circles indicate localities for Decarthrocerus jeanneli Orchymont, 1948 (bordered circle type locality).