Murmidius australicus, Jałoszyński & Ślipiński, 2022

Jałoszyński, Paweł & Ślipiński, Adam, 2022, Revision of the family Murmidiidae (Coleoptera: Coccinelloidea), Zootaxa 5109 (1), pp. 1-102 : 26-28

Murmidius australicus sp. n.

( Figs 59–66 )

Type material examined. Holotype ( Australia): sex unknown, “ 32.08S 151.27E / Allyn River / Chichester S.F. / NSW 10-11 Nov. / 1981 T.Weir”, “Berlesate / ANIC 748 / rainforest / leaf litter” ( ANIC) . Paratypes (18 exx): 1 ♂ and 2 exx of unknown sex, “ 10km ESE of / Moruya NSW / 27 Oct. 1982 / Doyen and / Lawrence”, “under bark / and in / rotten wood”; 3 exx, “ 35.22S 148.50E / Blundells Ck. 3km / E of Piccadilly / Circus, 850 m, ACT / Feb.1984 Weir, / Lawrence, Johnson”, “flight intercept / window/trough / trap”; 1 ex., same data but Jan. 1985; 5 exx, “ 35.30 S 150.18E / Kioloa SF 15km NE / Batemans Bay , NSW / Dec. 86 M. G.Robinson / flight interc.trap” [one specimen lacking the last label line]; 3 exx, “ Bunya Mts, S.E.Eld. / 17-18.ix.1966 / G. Monteith ”; 1 ex., “ 11.43S 142.41W QLD / 12km EbyN Heathlands / 18 Jan. 1992 / T. A.Weir, I.D.Naumann ”, “Berlesate / ANIC 1215 / closed forest / litter”; 5 exx (mounted on two separate pins), “ DAMS / 9.12.33”, “ J.G. Brooks / Bequest 1976”; 4 exx “Tamworth N.S.W./ 9-12-92. Lea”; 1 ex “ Mt. Tambourine / Q A.M. Lea ” (paratypes in ANIC, MNHW, SAM, QMB) .

Diagnosis. Body oval, strongly flattened, light brown; antennal club short oval; anterior clypeal margin microserrate; pronotum with distinct lateral longitudinal impressions and sublateral impressions, the latter nearly reaching pronotal base and in most specimens are anteriorly connected by transverse groove or impression accentuating swollen anterior pronotal margin; elytral punctures arranged in distinct rows on entire disc; punctures on head dorsum and pronotal disc uniform, very fine and shallow; prosternal carinae reaching anterior 2/3 of prosternum; mesoventral plate with evenly rounded anterior margin and submarginal carina incomplete, developed only on sides; elytral epipleura not narrowed at the level of metaventrite; metaventrite with large, alveolate punctures on sides; penis conspicuously long and slender, in lateral view weakly, almost evenly curved with flattened apical region; median strut almost as long as tegmen; tegmen with truncate apex bearing several pairs of moderately long setae.

Description. BL 1.05–1.48 mm; BL/EW 1.50–1.62. Body elongate oval ( Figs 59–60 ) and in lateral view dis- tinctly flattened ( Fig. 62 ); pigmentation light brown, legs slightly to distinctly lighter; dorsum covered with moderately sparse, short whitish setae in most specimens well-visible under magnification 40 ×; cuticle moderately glossy, on frons and clypeus distinctly finely microreticulate, on pronotum microreticulation less distinct, and even less so on elytra.

Head 0.25–0.38 mm wide; frons weakly convex, with dense and somewhat diffuse, shallow punctures separated by spaces subequal to their diameters; clypeus more matt than frons; eyes large, strongly convex, coarsely faceted. Antennal club ( Fig. 59 ) short, oval.

Pronotum ( Figs 59–60 ) strongly transverse, widest at base; PL 0.25–0.30 mm, PW 0.53–0.73 mm, PL/PW 0.37–0.48; lateral margins weakly rounded or, especially in small specimens, nearly straight, weakly convergent anterad, with narrow lateral carinae; mesal corners of antennal cavities distinctly projecting anterad; lateral longitudinal impressions distinct, broad and deep anteriorly and reducing in width and depth toward pronotal base, subparallel to lateral pronotal margins; sublateral longitudinal impressions distinct, in most specimens posteriorly reaching nearly pronotal base, only rarely shortened, anteriorly connected by transverse impression or groove; anterior pronotal margin in front of transverse groove in most specimens distinctly elevated, swollen. Punctures on disc very fine, shallow and somewhat diffuse, densely distributed, those on median area separated by spaces subequal to their diameters, large punctures lacking.

Prosternum ( Fig. 61 ) smooth with fine, inconspicuous punctures; prosternal carinae anteriorly reaching 2/3 of prosternum; notosternal carinae strongly recurved, nearly reaching anterior prosternal margin, the latter with narrow marginal carina.

Elytra ( Figs 59–60 ) together oval, with rounded sides, broadest near middle, EL 0.75–1.10 mm, EW 0.73–0.98 mm, EL/EW 1.10–1.17. Humerus with distinct, bulging callus; each elytron with 9 longitudinal rows of large, dis- tinct but shallow punctures, 2 lateralmost rows often with gaps or less regular; surface between rows glossier than pronotum.

Hind wings fully developed.

Mesoventral plate ( Fig. 63 ) with lateral longitudinal carinae anteriorly curved mesad, but most of evenly round- ed anterior margin lacking submarginal carina.

Metaventrite ( Fig. 63 ) on most of its surface virtually impunctate, except for sides which are covered with unevenly distributed large, circular punctures with flat bottoms, with several arranged in row along posterior margin of metaventral femoral line. Discrimen externally visible in some specimens, in others indiscernible.

Tarsi with long but inconspicuous setae on tarsomeres 1–3.

Aedeagus ( Figs 64–66 ) 0.42 mm long, conspicuously slender; penis in ventral view with subtriangular, rounded apex, in lateral view weakly curved and extremely thin, with flattened apical region; tegmen with undivided, truncate apex bearing about 4 pairs of moderately long setae; median strut almost as long as tegmen.

Distribution. Australia (New South Wales and Queensland).

Etymology. Named after the country and continent where it occurs.

Remarks. Specimens from Australia were previously identified as M. ovalis , but already Hinton (1942) noticed and discussed morphological differences between European, Oriental and Australian populations. His observations are here corroborated by examination of fine details and the male genitalia, which turned to be distinct from those of M. ovalis .

Adults of M. australicus are highly variable in the body length and proportions of body parts, but stable in the relatively light brown pigmentation, oval and strongly flattened body, distribution of punctures and microsculpture, and length of prosternal carinae. Murmidius australicus and M. ovalis are the only round and oval species with microserrate (or crenulate) anterior clypeal margin (the third species with this feature, M. tydeus , is conspicuously elongate); both are very similar to each other also in pigmentation, presence of lateral longitudinal pronotal impression, incomplete submarginal carina on the mesoventral plate, and distinct longitudinal rows of elytral punctures. Murmidius australicus is always distinctly flatter, and its pronotum bears more distinct and usually longer sublateral longitudinal grooves. The grooves tend to be anteriorly connected by a transverse impression running along swollen anterior pronotal margin, which is a conspicuous character that M. ovalis lacks. However, unusually small speci- mens may have the submedian impressions less pronounced and the transverse impression more diffuse. In doubtful cases the aedeagus is an unambiguous key structure, in M. australicus being clearly slenderer, with particularly thin penis compared to that in M. ovalis .

Figures

FIGURES 59–66. Morphological structures of Murmidius australicus sp. n. Body in dorsal (59–60), ventral (61) and lateral (62) views; pterothorax in ventral view (63); aedeagus (64), isolated tegmen (65) and penis (66).