Kerteszomyia guamensis Sasakawa 2017, n. sp.
Creators: name: Sasakawa, Mitsuhiro
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Lauxaniidae
Kerteszomyia
Kerteszomyia guamensis

description: 1. Kerteszomyia guamensis Sasakawa, n. sp.
Type material. Holotype male (USNM), Mt. Lamlam, Guam, Mariana Is., X 1957, NK. Paratypes: 2♀, same data as holotype (USNM); 1♀, Pilgo River, 26 V 1945, GB & JG (BPBM); 1♂, Mt. Balanas, VIII 1952, NK (USNM); 1♀, Pt. Ritidian, X 1952, NK (USNM); 2♀, Yigo, X 1957 & II 1958, NK (USNM).
Diagnosis. Small, yellow species, with wing 2.4 (♀)–2. 7 (♂, holotype) mm long; mesoscutum yellow, with two pale brown vittae just inside of dc-rows (indistinct in male), 1+2 dc and two rows of acr; sternopleuron with two stpl; costal spinules extending to basal 1/3 between apices of R 2 +3 and R 4 +5, ultimate section of CuA 1 about 1/5 length of penultimate; fore femur without ctenidium of setae, tibiae each with posterodorsal seta (pd) apically; hypandrium Vshaped, distiphallus tubular (fig. 1).
Description. Male. Head yellow; ocellar triangle dark brown; base of outer vertical bristle (vto) to occiput obliquely through dorsal postorbit pale brown; triangular angle between parafrontalia and parafacialia laterad of antennal base brown; antenna brown but inside of scape and pedicel yellow and ventral margin of first flagellomere yellowish, arista brown; palpus yellow. Thorax yellow; mesoscutum sparsely greyish-dusted, with central vittae indistinct (holotype) or distinct and extending to scutellum as anterior spot (paratype), and also lateral side below level of presutural (prs), supra-alar (sa) and post-alar (pa) bristle line pale brown, extending posteriorly to lateral sides of scutellum, both scutellar bristles (sc) growing on yellow area; pleura entirely yellow (holotype) or notopleuron ventrally and dorsal margins of meso- and sternopleura narrowly pale brown (paratypes). Wing hyaline, very faintly yellowish tinged; veins brownish yellow but yellow at base; calypter yellow, with fringe yellowish brown; halter yellow; legs yellow. Abdomen weakly shining, yellow, each tergite sometimes brown-tinged anteriorly.
Frons about 1.4 times as wide as eye, parallel-sided or slightly converging ventrally, sparsely setulose ventrally; fronto-orbital setae (or) two, upper one slightly longer than lower and shorter than inner vertical bristle (vti), orbital setulae (os) only two; postocellar bristle (poc) below vertex longer than oc which is about 1/2 length of vti; eye with white minute hairs very sparsely; gena about 1/3 eye height, with four (rarely three) long pm; first antennal flagellomere suborbicular, rounded apically, as long as wide, with pile whitish; arista almost as long as width of eye, minutely pubescent. Mesoscutum with acr in inner row distinct but only several ones in outer row and prsc about half length of posteriormost dc; scutellum with basal sc inclinate, apical sc divergent; mesopleuron with a long bristle (mspl), sternopleuron with two bristles (stpl); fore femur with four posteroventral setae, hind femur with one anterodorsal seta preapically; mid tibia with a long spur. Wing length 2.7 mm; costa with three sections in ratio of 3.6 (3.4–4.3): 1.0 (–2.0): 0. 7(–0.6), r-m slightly at proximal position of discal cell, M1 ratio 1.6: 1. Genitalia (Fig. 1): epandrium with long setae sparsely, surstylus with long setae posteriorly and many short setae along inner ventral margin; cercus almost as high as surstylus; phallus almost as long as hypandrium, distiphallus about 1.5 times length of basiphallus. Body length 2.5–2.7 mm.
Female. Similar to male, but wing shorter, 2.4–2.6 mm; costal ratio as 3.4–4.3: 1.0: 0.7, r-m usually at midpoint of discal cell, M 1 ratio 2.1–2.3; body length 2.5–2.7 mm.
Distribution. S. Mariana (Guam).
Remarks. This new species is immediately distinguishable by the pale brown bivittate mesoscutum, and much smaller in size than the immaculate K. maculifrons Malloch (1929a), the type species of the genus known from Luzon, Philippines. Two stpl in this species are also seen in a species (not described yet) from Madagascar (Stuckenberg, 1971), but only one in K. maculifrons.
description: Published as part of Sasakawa, Mitsuhiro, 2017, Insects of Micronesia, Volume 14, no. 10 Diptera: Lauxaniidae (Part 2), pp. 1-5 in Micronesica 2017 (2) on pages 1-2, DOI: 10.5281/zenodo.12117838