Rugosimirax bimacula Liu & Polaszek 2024, sp. nov.

Rugosimirax bimacula sp. nov.

urn:lsid:zoobank.org:act: 58EFC8C7-A0F5-4DD0-9DE2-1B6656DA94A3

Fig. 2

Diagnosis

Body length 1.5 mm, light yellow-brown; head transverse, eyes 2.4 × as long as temple dorsally; POL:OD:OOL = 3.4:1.0:1.8; frons flat in front of anterior ocellus, and impunctate at sides; clypeus 2.0 × as wide as medial length; notaular courses obvious only in anterior ¼; scutellar hind depressions distinct, oblong elliptical and close to each other with carina separating them; propodeum with oblique rugae at sides, and transverse rugae which form open and ill-defined U-shaped areola; vein 1-R1 very short, indistinct as a extension of pterostigma; T2 1.8 × as wide as median length; ovipositor sheath 1.2 × as long as hind basitarsus, with long and dense setae apically.

Etymology

The specific epithet ‘ bimacula ’ derives from Latin, referring to two pale maculae on basal and apical pterostigma.

Material examined

Holotype BRUNEI • ♀; Pagon Ridge; 8 Feb.1982; B.C.St.G. Allen leg.; NHMUK010639289.

Description

Female

MEASUREMENT. Body length 1.5 mm, fore wing length 1.9 mm (Fig. 2a).

HEAD. Transverse in dorsal view, 1.9 × as wide as long, 1.2 × as wide as mesoscutum. Eyes 2.4 × as long as temple dorsally. Temple smooth, nearly impunctate, except minute hairy punctures and shiny, constricted behind eyes in dorsal view (Fig. 2b). Ocelli small, distance between fore and hind ocellus 1.4 × as long as transverse diameter of a hind ocellus, POL:OD:OOL = 3.4:1.0:1.8, anterior ocellus clearly flat anteriorly and impunctate at sides. Face (Fig. 2c) polished, except superficial small punctures close to the eyes, setose and shiny, convex medially, transverse, 1.4 × as wide as high. Clypeus 2.0 × as wide as medial length. Antenna (Fig. 2d) as long as body length, with scape, pedicel and 1 st, 2 nd, penultimate and ultimate flagellomeres 1.8, 2.0, 5.1, 4.2, 2.9 and 3.6 × as long as wide, 1 st 1.2 × as long as 2 nd, other flagellomeres subsequent to 2 nd nearly the same size as 2 nd.

MESOSOMA. Length:width:height = 11.5:7.5:8.0. Mesonotum (Fig. 2e) shiny with distinct punctures anteriorly, becoming shallower towards posterior half and polished along posterior margin, notaular courses only obvious in anterior ⅓. Scutellar sulcus slightly curved, narrow, not crenulated. Scutellum shiny with minute hairy punctures, largely glabrous medio-posteriorly, scutellar hind depressions distinct, oblong-elliptical and close to each other, separated by a carina. Propodeum shiny, with oblique rugae at sides and transverse rugae forming open and ill-defined U-shaped areola, elsewhere nearly polished. Mesopleuron highly polished, impunctate.

LEGS. Hind femur (Fig. 2h) 3.5 × as long as its widest part. Length of hind femur:tibia:basitarsus = 2.0:2.3:1.0. Basitarsus of hind leg 0.6 × as long as tarsomeres 2–5.

WINGS. Fore wing (Fig. 2g): pterostigma narrow, 3.2 × as long as its widest part; vein 1-R1 present, indistinct as a extension of pterostigma; vein r:2-SR:2-M = 1.0:3.8:2.2, 1-SR:1-M = 1.0:3.0, 1-CU1:2- CU1 =1:1.4; first discal cell of fore wing 1¼ × as wide as high. Hind wing: vein M+CU:1-M:r-m = 1.9:2.4:1.0.

METASOMA. Nearly as long as mesosoma. T1 (Fig. 2i) smooth, spoon-shaped (attenuated apically), 1.8 × as long as its maximum width, indistinctly narrowed medially. T2 1.8 × as wide as median length. T3 about as long as T2, longitudinally striate. Hypopygium not as long as apex of metasoma. Ovipositor sheath 1.2 × as long as hind basitarsus, with long and dense setae apically.

COLOUR. Light yellow-brown (Fig. 2a). Palpi and spurs pale yellow. Flagellomeres and apex of ovipositor sheath dark brown. Legs more yellow, except apical tarsomeres. Wing membrane hyaline, pterostigma (except basal and apical paler maculae), vein r, 2-SR, 1-SR, 1-M and 1-CU1 brown, other veins light brown.

Male

Unknown.

Host

Unknown.

Distribution

Borneo (Brunei).

Remarks

This species is peculiar in Rugosimirax for having the hind depressions close to each other, with a carina separating them. R. bimacuila is close to Rugosimirax obsolescens sp. nov. but can be easily differentiated from it by the characters in the key.

Discussion

Species of Miracinae have never been well-classified into genera, despite having only 70 species worldwide. The problem is largely due to the use of different diagnostic criteria for the included species listed in each review (Papp 2013; Ranjith et al. 2019; Ghramh et al. 2019; Slater-Baker et al. 2022). To better distinguish Centistidea from Mirax, we have checked all the descriptions of species and identified specimens including primary types in the NHM collection. We have found that the sculpture on the propodeum, and the degree of development of the notauli could be a practical way to separate these three genera, though they often overlap in other characters (see the genus key below).