Murmidius irregularis Reitter

Jałoszyński, Paweł & Ślipiński, Adam, 2022, Revision of the family Murmidiidae (Coleoptera: Coccinelloidea), Zootaxa 5109 (1), pp. 1-102 : 56-58

Murmidius irregularis Reitter

( Figs 163–169 )

Murmidius irregularis Reitter, 1878: 165 .

Murmidius chapini Hinton, 1935: 274 ; syn. n.

Type material examined. Lectotype [here designated by A. Ślipiński] ( Mexico): unknown sex, “ M. irregularis / m. n.sp. Reitt. / Teapa Type”, “?Plata 60. / alius /?familiae / Teapa” [faded and unreadable], two unreadable labels, “Type”, “B.C.A.,Col.II,(1)” ( BMNH) . Holotype of Murmidius chapini ( Guatemala) : ♂, “Alta V. Paz / aGuatema- la” “27.4 Cacao / TreceAguas”, “Schwarz & / Barber coll.”, “TypeNo. / 63551, U.S. N.M.”, “ Holotype / Murmidius / chapini / Hinton”, “Type, Murmidius / chapini / 34 Hntn.” ( USNM) .

Emended diagnosis. Body short oval and weakly convex, chestnut brown; antennal club only slightly elongate; anterior clypeal margin smooth; pronotum lacking lateral and sublateral longitudinal impressions; clypeus with extremely fine microreticulation, frons and vertex with indistinct, superficial traces of microreticulation, pronotum and elytra lacking microsculpture; elytra with fine but distinct and dense punctures not arranged in rows; prosternal carinae as long as 3/4 of prosternum; mesoventral plate with evenly rounded anterior margin, lacking submarginal carina but with distinct lateral carinae curving anteromesad and nearly reaching anterior mesoventral margin; elytral epipleura not strongly narrowed at the level of metaventrite where they are nearly as wide as width of mesofemur; metaventrite with large, circular, unevenly distributed punctures on sides; penis slender, in lateral view distinctly but weakly curved; in ventral view largely sub-parallel with broadly rounded apex; tegmen as long as half of penis, with rounded apex bearing one pair of short setae, in addition subapical area with two longitudinal rows of minute setae distant from sides of tegmen.

Redescription. BL 1.08–1.20 mm; BL/EW 1.30–1.50. Body short oval ( Figs 163–165 ) and in lateral view weakly convex ( Fig. 166 ); pigmentation chestnut or reddish-brown; dorsum covered with extremely short whitish setae (discernible under magnification 80 ×); cuticle glossy, on clypeus distinctly but very finely microreticulate, superficial traces of reticulation can also be seen on frons and vertex.

Head 0.30–0.33 mm wide; frons and vertex weakly convex, with fine but distinct and dense punctures separated by spaces subequal to their diameters; clypeus less glossy than frons; eyes large, strongly convex, coarsely faceted. Antennal club only slightly elongate.

Pronotum ( Figs 163–164 ) strongly transverse, widest at base; PL 0.23 mm, PW 0.58–0.63 mm, PL/PW 0.36– 0.39; lateral margins weakly rounded and moderately strongly convergent anterad, with fine and narrow lateral carinae; mesal corners of antennal cavities weakly projecting anterad; lateral and sublateral longitudinal impressions lacking; anterior pronotal margin lacking marginal line. Punctures on disc fine and barely discernible, except for anterolateral groups of large and distinct punctures that extend mesad along anterior pronotal margin.

Prosternum ( Fig. 165 ) with barely discernible transverse microreticulation and with fine, inconspicuous setiferous punctures; prosternal carinae about as long as 3/4 of prosternum and their anterior portions distinctly curved laterad; notosternal carinae nearly straight and nearly reaching anterior prosternal margin, the latter with distinct narrow marginal carina.

Elytra ( Figs 163–164 ) together oval, with strongly rounded sides, broadest distinctly in front of middle, EL 0.70–0.83 mm, EW 0.80–0.83 mm, EL/EW 0.85–1.03. Humerus with distinct callus; elytra densely punctate, punc- tures small but distinct, not arranged in rows, those on anteromedian region of each elytron separated by spaces 1–1.5 × as wide as their diameters, punctures slightly reducing in depth toward sides and apices. Epipleura not narrowed near middle, with convex margins.

Hind wings fully developed.

Mesoventral plate ( Fig. 167 ) with fine lateral longitudinal carinae curved anteromesad and not connected into anterior submarginal carina; anterior margin evenly, broadly rounded.

Metaventrite ( Fig. 167 ) with large, circular and distinct punctures unevenly distributed on sides; median region with fine, inconspicuous setiferous punctures. Discrimen externally indiscernible.

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

Aedeagus ( Figs 168–169 ) 0.30 mm long, moderately slender; penis in ventral view largely sub-parallel with broadly rounded apex, in lateral view distinctly but weakly curved; tegmen stout, as long as half-length of penis, with broadly rounded apex bearing one pair of short setae accompanied by two longitudinal rows of minute setae distant from lateral margins of tegmen.

Distribution. Central America: S Mexico and Guatemala.

Remarks. Although the fragile lectotype of M. irregularis was not dissected, the synonymy with M. chapini seems well supported by almost identical body shape and external structures, as well by distribution in southern Mexico and Guatemala. These two specimens are both conspicuously small and short oval. There are similarly small specimens among those identified as M. stoicus (which typically is larger than M. irregularis ), but they come from distant regions ( China, Myanmar) and clearly differ in genital structures.

Figures

FIGURES 163–169. Morphological structures of Murmidius irregularis Reitter. Body in dorsal (163–164), ventral (165) and lateral (166) views; pterothorax in ventral view (167); and aedeagus (168–169).