Murmidius convexus, Jałoszyński & Ślipiński, 2022

Jałoszyński, Paweł & Ślipiński, Adam, 2022, Revision of the family Murmidiidae (Coleoptera: Coccinelloidea), Zootaxa 5109 (1), pp. 1-102 : 72-74

Murmidius convexus sp. n.

( Figs 220–226 )

Type material examined. Holotype ( Brazil): sex unknown, “Nova Teutonia, Sta. / Catarina, / Braz. / XII:14:51 / Fritz Plaumann leg.” ( FMNH) . Paratypes (3 exx): 1 ex., same data as for holotype but 09.08.1957 ; 1 ♂, “ Rio Caraguata , M. Grosso / Brazil V:1953 / 21º 48’; 52º 27’; 400M. alt. / Fritz Plaumann leg.” ; 1 ♀, same data except for “III:1953” ( FMNH) .

Diagnosis. Body short oval and moderately convex, moderately to dark brown; antennal club only slightly elongate; anterior clypeal margin smooth; pronotum lacking lateral and sublateral longitudinal impressions; clypeus with fine microreticulation, semi-matt, reticulation on frons, vertex and pronotum indistinct, surface glossy, elytra smooth and glossy; elytra with fine and dense but inconspicuous punctures not arranged in rows; prosternal carinae about as long as 3/4 of prosternum, with anterior portions distinctly divergent anterad; mesoventral plate with evenly and relatively weakly rounded anterior margin, with distinct anterior submarginal carina but lacking lateral carinae; elytral epipleura not strongly narrowed at the level of metaventrite where they are much narrower than width of mesofemur; metaventrite with strong but small, not alveolate punctures on sides; penis slender, in lateral view strongly curved; in ventral view penis largely parallel-sided and only with apical portion gradually narrowing toward subtriangular, pointed apex; tegmen slender, tapering from base to subtriangular apex bearing three pairs of moderately long setae.

Description. BL 1.23–1.50 mm; BL/EW 1.32–1.40. Body short oval ( Figs 220–222 ) and in lateral view mod- erately convex ( Fig. 223 ); pigmentation moderately dark, slightly reddish-brown; dorsum covered with extremely short whitish setae (barely discernible under magnification 80 ×); clypeus with distinct, very fine, semi-matt microreticulation, reticulation on frons, vertex and pronotum indistinct, surface glossy, elytra smooth and glossy.

Head 0.33–0.40 mm wide; frons and vertex weakly convex, with fine, shallow and dense punctures; clypeus semi-matt; eyes large, strongly convex, coarsely faceted. Antennal club only slightly elongate.

Pronotum ( Figs 220–221 ) strongly transverse, widest at base; PL 0.25–0.30 mm, PW 0.68–0.80 mm, PL/PW 0.37–0.38; lateral margins weakly rounded and moderately strongly convergent anterad, with narrow but distinct lateral carinae; mesal corners of antennal cavities weakly projecting anterad; lateral and sublateral longitudinal impressions lacking; anterior pronotal margin with distinct marginal line. Punctures on disc uniform, fine and dense, inconspicuous.

Prosternum ( Fig. 222 ) with barely discernible transverse microreticulation and with fine, inconspicuous setiferous punctures; prosternal carinae about as long as 3/4 of prosternum and with slightly curved outwards distal ends; notosternal carinae arcuate and not reaching anterior prosternal margin, the latter lacking marginal carina.

Elytra ( Figs 220–221 ) together oval, with strongly rounded sides, broadest indistinctly in front of middle, EL 0.88–1.08 mm, EW 0.93–1.08 mm, EL/EW 1.00–1.09. Humerus with distinct callus; elytra densely but finely punctate, punctures shallow, inconspicuous, not arranged in rows, those on anteromedian region of each elytron separated by spaces subequal to their diameters, punctures reducing in depth toward sides and apices. Epipleura not narrowed near middle, with convex margin.

Hind wings fully developed.

Mesoventral plate ( Fig. 224 ) lacking lateral longitudinal carinae, with distinct and complete anterior submarginal carina; anterior margin evenly, broadly, but not strongly rounded.

Metaventrite ( Fig. 224 ) with distinct, not alveolate and small punctures on sides; median region with fine, inconspicuous setiferous punctures. Discrimen externally poorly discernible.

Tarsi with short, inconspicuous setae on tarsomeres 1–3.

Aedeagus ( Figs 225–226 ) 0.70 mm long, very slender; penis in ventral view tubular up to short, tapered, subtriangular and pointed apical region, in lateral view penis strongly curved; tegmen slender, as long as half of penis, tapering from base to subtriangular apex bearing three pairs of moderately long setae.

Distribution. Neotropical ( Brazil).

Etymology. The specific epithet convexus refers to the body form.

Remarks. Murmidius convexus closely resembles M. drakei . Both species are Neotropical and show some variability in the body shape, length and pigmentation. Adults of M. convexus tend to be larger and more convex, with darker pigmentation. It seems that the prosternal carinae can be used to distinguished these species, as among the studied specimens those identified as the new species M. convexus have the carinae clearly divergent anterad, whereas M. drakei has the carinae almost perfectly parallel. More specimens are needed to assess whether this is a constant character. A constant external difference seems to be the anterior submarginal carina of the mesoventral plate, which is complete in M. convexus and broadly obliterated at middle in M. drakei . The most reliable features are associated with the aedeagus: in M. convexus the tegmen is tapering towards subtriangular apex, whereas that in M. drakei is parallel-sided and truncate.

Figures

FIGURES 220–226. Morphological structures of Murmidius convexus sp. n. Body in dorsal (220–221), ventral (222) and lateral (223) views; pterothorax in ventral view (224); and aedeagus (225–226).