Murmidius melon, Guerrero, Ramirez & Vidal, 2018

Jałoszyński, Paweł & Ślipiński, Adam, 2022, Revision of the family Murmidiidae (Coleoptera: Coccinelloidea), Zootaxa 5109 (1), pp. 1-102 : 49-50

Murmidius melon Guerrero, Ramírez & Vidal

( Figs 142–148 )

Murmidius melon Guerrero, Ramírez & Vidal, 2018: 386.

Material examined. Chile: 1 ♂, 6 ♀♀ and 2 exx of unknown sex, Zapallar, Acontagua, 27.xi.1950, leg. Ross & Michelbacher ( CAS) ; 1 ex., Quebrada El Tigre, Prov.Aconcagua, 12.viii.1966, 32°31’S, 71°26’W, leg. E. Schlinger & M. Irwin ( CAS) .

Emended diagnosis. Body short, oval, moderately convex, reddish brown to nearly pitchy black; antennal club slightly elongate; anterior clypeal margin smooth; pronotum with distinct lateral longitudinal impressions, lacking sublateral impressions; entire head and pronotum with fine microsculpture on head taking form of indistinct, fine reticulation, on pronotum superficial and not forming closed meshes, moderately glossy; pronotum with fine, inconspicuous punctures; elytra impunctate, with traces of superficial microreticulation not forming closed meshes, more glossy than head and pronotum; prosternal carinae long, anteriorly slightly exceeding middle of prosternum; mesoventral plate with shallowly bisinuate anterior margin with distinct median projection, lacking submarginal carina, with complete lateral carinae which are weakly oblique and weakly convergent anterad, large area between mesal margin of mesocoxa and lateral mesoventral carina distinctly microreticulate; elytral epipleura not narrowed at the level of metaventrite and broad, near middle about as broad as width of mesofemur; metaventrite virtually impunctate; penis slender and subcylindrical, in lateral view strongly curved; in ventral view largely parallel-sided except for gradually narrowing, subtriangular, pointed apex; tegmen moderately slender, with shallowly emarginate apex bearing two pairs apical setae of which one is conspicuously long, and the other barely noticeable.

Redescription. BL 1.33–1.45 mm; BL/EW 1.29–1.37. Body short, oval ( Figs 142–143 ) and in lateral view moderately convex ( Fig. 145 ); pigmentation reddish brown to pitchy black, legs slightly lighter than dorsum; dorsum very finely setose (setae whitish and well-visible under magnification 40 ×) and glossy, with fine microreticulation on head, and traces of superficial microsculpture on pronotum and elytra, lacking closed meshes, least distinct on elytra.

Head 0.35–0.40 mm wide, entirely finely microreticulate but not matt; frons and vertex weakly convex, with indistinct and sparse punctures obscured by microsculpture; clypeus similarly microreticulate as frons and vertex; eyes large, strongly convex, coarsely faceted. Antennal club weakly elongate.

Pronotum ( Figs 142–143 ) strongly transverse, widest at base; PL 0.23–0.28 mm, PW 0.73–0.85 mm, PL/PW 0.29–0.34; lateral margins weakly rounded and strongly convergent anterad, with narrow lateral carinae; mesal corners of antennal cavities distinctly projecting anterad; lateral longitudinal impressions distinct, step-wise demarcated laterally and gradually becoming shallower mesally, broad and deep anteriorly and reducing in width and depth toward pronotal base, their lateral margin parallel to lateral pronotal margins; sublateral longitudinal impressions lacking; anterior pronotal margin demarcated by distinct marginal line. Punctures on disc fine and obscured by extremely fine microsculpture lacking well-defined, closed meshes.

Prosternum ( Fig. 144 ) with fine transverse microreticulation especially distinct anterad and laterad prosternal carinae and with fine, indistinct punctures; prosternal carinae slightly exceeding half of prosternum; notosternal carinae indistinctly sinuate and nearly reaching anterior prosternal margin, the latter with narrow marginal carina.

Elytra ( Figs 142–143 ) together oval, with strongly rounded sides, broadest distinctly in front of middle, EL 1.03–1.15 mm, EW 1.05–1.13 mm, EL/EW 1.00–1.05. Humerus lacking callus; elytra virtually impunctate; surface with indistinct, superficial traces of microsculpture, moderately glossy.

Hind wings absent.

Mesoventral plate ( Fig. 146 ) with complete lateral longitudinal carinae weakly convergent anterad, posterior end of each carina distant from mesocoxa; anterior margin shallowly bisinuate, with median projection, lacking submarginal carina. Large area laterad each longitudinal carina and mesad mesocoxae distinctly reticulate.

Metaventrite ( Fig. 146 ) with sparse and fine setiferous punctures. Discrimen externally well-marked in some specimens, in others indiscernible.

Tarsi with short, inconspicuous setae on tarsomeres 1–3 ( Fig. 144 ).

Aedeagus ( Figs 147–148 ) 0.30 mm long, slender; penis nearly tubular, in ventral view largely parallel-sided except for gradually tapering, subtriangular and pointed apex, in lateral view strongly curved; tegmen relatively slender, with shallowly emarginate apex bearing two pairs of conspicuously unequal apical setae: one extremely long, and one barely discernible.

Distribution. Neotropical ( Chile).

Remarks. Murmidius melon is extremely similar to M. globosus ; see Remarks for the latter species.

Figures

FIGURES 142–148. Morphological structures of Murmidius melon Guerrero, Ramírez & Vidal. Body in dorsal (142–143), ventral (144) and lateral (145) views; pterothorax in ventral view (146); and aedeagus (147–148).