Murmidius tydeus Hinton

Jałoszyński, Paweł & Ślipiński, Adam, 2022, Revision of the family Murmidiidae (Coleoptera: Coccinelloidea), Zootaxa 5109 (1), pp. 1-102 : 30-32

Murmidius tydeus Hinton

( Figs 74–80 )

Murmidius tydeus Hinton, 1942: 4 .

Type material examined. Holotype ( Singapore): sex unknown, “Singapore, C.J. Saunders ”, “ BM 1929-369 ”, “ Murmidius tydeus Hinton ”, “Type” ( BMNH).

Additional material examined. W Malaysia: 3 exx, Pahang, Tioman Is., Kg. Tekek vic., 15-26.vii.1992, R . Schuh leg. ( RSH, MIZ); 1 ♂ , Terengganu, Tesik Kenyir , 26.vii. - 2.viii.1999, H. Forster leg. ( NHMB) .

Emended diagnosis. Body strongly elongate, oval, weakly convex, dark brown; anterior clypeal margin microserrate; antennal club short oval; pronotum with distinct lateral longitudinal impressions and fine but distinct sublateral impressions, the latter as long as half-length of pronotum and anteriorly not connected by transverse groove; anterior pronotal margin barely noticeably swollen; elytral punctures arranged in distinct rows on entire disc and somewhat elongate; punctures on head dorsum fine and dense, uniform; punctures on pronotal disc larger than those on frons, dense and sharply marked, in addition pronotum with sparse larger punctures near anterior margin between sublateral impressions; antennal club short oval; prosternal carinae nearly reaching anterior 2/3 of prosternum; mesoventral plate with broadly subtriangular anterior margin and complete submarginal carina, laterally confluent with longitudinal lateral carinae; elytral epipleura not narrowed at the level of metaventrite; metaventrite with large but not alveolate punctures on sides; penis remarkably slender, with rounded apex, in lateral view strongly curved with rounded apical region; median strut nearly as long as tegmen; tegmen with shallowly emarginate apex bearing three pairs of short setae.

Redescription. BL 1.25–1.30 mm; BL/EW 1.73–1.76. Body strongly elongate oval ( Figs 74–75 ) and in lateral view weakly convex ( Fig. 77 ); pigmentation dark brown with reddish hue, legs indistinctly lighter; dorsum covered with sparse, extremely short whitish setae barely noticeable under magnification 40 ×; cuticle moderately glossy, on clypeus indistinctly and very finely microreticulate, on remaining body parts only barely discernible, superficial traces of microsculpture can be seen.

Head 0.31–0.33 mm wide; frons weakly convex, with fine, dense and sharply marked but shallow punctures separated by spaces subequal to their diameters; clypeus more matt than frons; eyes large, strongly convex, coarsely faceted. Antennal club ( Fig. 76 ) short, oval.

Pronotum ( Figs 74–75 ) strongly transverse, widest at base; PL 0.25 mm, PW 0.60–0.63 mm, PL/PW 0.40–0.42; lateral margins nearly straight, weakly convergent anterad, with narrow lateral carinae; mesal corners of antennal cavities distinctly projecting anterad; lateral longitudinal impressions distinct, narrow and deep, sulciform, reducing in width and depth toward pronotal base, subparallel to lateral pronotal margins; sublateral longitudinal impressions fine, in some specimens composed of several connected large punctures, but distinct, posteriorly reaching middle of pronotum; anterior pronotal margin barely noticeably swollen. Punctures on disc larger than those on frons, densely distributed, those on median area separated by spaces subequal to their diameters, punctures between lateral and sublateral impressions less distinct, large punctures present and unevenly distributed near anterior pronotal margin between sublateral impressions.

Prosternum ( Fig. 76 ) smooth with fine, inconspicuous punctures; prosternal carinae anteriorly nearly reaching 2/3 of prosternum; notosternal carinae slightly recurved, not reaching anterior prosternal margin, the latter with narrow marginal carina along middle portion.

Elytra ( Figs 74–75, 77 ) together oval, with weakly rounded sides, broadest near middle, EL 0.93–0.98 mm, EW 0.73–0.75 mm, EL/EW 1.28–1.31. Humerus with distinct, bulging callus; each elytron with 9 longitudinal rows of distinct, large but shallow oval punctures, 2 lateralmost rows less regular; surface between rows virtually impunctate.

Hind wings fully developed.

Mesoventral plate ( Fig. 78 ) with lateral longitudinal carinae anteriorly curved mesad and confluent with complete submarginal carina; anterior margin broadly subtriangular, indistinctly angulate at middle.

Metaventrite ( Fig. 78 ) on most of its surface very finely and sparsely punctate, on sides with unevenly distributed large, slightly elongate shallow punctures. Discrimen externally visible in some specimens, in others indiscernible.

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

Aedeagus ( Figs 79–80 ) 0.38 mm long, strongly elongate; penis in ventral view with rounded apex, in lateral view strongly but not evenly curved, with rounded apex; tegmen with shallowly emarginate apex bearing three pairs of short setae; median strut nearly as long as tegmen.

Distribution. Malay Peninsula.

Remarks. This is a remarkable species easy to identify by its strongly elongate body, narrow and short but wellmarked sublateral pronotal impressions, densely punctate pronotum with nearly straight sides and elytral punctures arranged in rows. The most elongate of all remaining Murmidius species is M. elongatus , which, however, is stouter, has more rounded sides of elytra, and does not have rows of punctures on the elytra.

Figures

FIGURES 74–80. Morphological structures of Murmidius tydeus Hinton. Body in dorsal (74–75), ventral (76) and lateral (77) views; pterothorax in ventral view (78); apical portion of penis (79) and aedeagus (80).