Meroplius angulospinus Kim & Kim, 2025, sp. nov.
Creators: name: Kim, Dongmin
name: Kim, Young-Kun
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Sepsidae
Meroplius
Meroplius angulospinus

description: Meroplius angulospinus sp. nov.
(Figures 1 and 2)
Type specimens. Holotype male: Donaenaruteo, Taean-eup, Taean-gun, Chungcheongnam-do, Republic of Korea, 36.817567°N, 126.321775°E, 25.V.2022, SJ Suh Coll. (KNU); paratypes: 1 male, 1 female, same data as holotype (KNU).
Diagnosis. This new species is particularly similar to M. fasciculatus (Brunetti, 1909) in the shape of the male fore femur spines and genitalia, but it can be easily distinguished by the following characteristics: the palpus is yellow (vs. black); the postpedicel is about 1.1–1.3 times as long as wide (vs. twice as long as wide); the apical half of the distal spine of the fore femur is much flatter and thicker (vs. not being); the male sternal appendage lacks very long plumose setae (vs. with very long plumose setae); the hypopygium does not have a clear sharp basal protrusion below the surstylus (vs. having one); and the surstylus has some inward-pointing dentation subapically (vs. does not have any) (Ozerov, 2018a). Additionally, the sternal appendages have setae along the upper margin and resemble those of the African species M. vikhrevi Ozerov, 2014 (Ozerov, 2014). However, most other species in this genus have distal spines on the fore femur that are straight and either oval or hair-like, whereas this species has an angular distal spine. The apical half of the spine is notably flatter and thicker, with a subtriangular or slightly boomerang shape, giving it a distinct appearance that makes it easily distinguishable from the other Meroplius species.
Description
Male. Body length: 3.1–3.4 mm; wing length: 2.2–2.5mm.
Head: Mostly dark; frontal vitta and fronto-orbital plate black, subshining, gradually darkening to brown toward lunule; face black with yellowish-brown facial carina; parafacial brown; gena dark brown, with height below eye slightly wider than 1/10 of vertical diameter of eye; 1 each of orbital, ocellar, inner vertical, outer vertical, postocellar, vibrissae, and numerous short subvibrissal setae present; outer vertical seta about 1.5 times longer than orbital seta (Figs. 1A–B). Antenna mostly brown to dark brown; scape dark brown; pedicel and postpedicel brown to light brown on inner surface, dark brown on outer surface, brown around articulation of pedicel and postpedicel; postpedicel rounded apically, about 1.1–1.3 times as long as wide; arista brown to dark brown, bare. Palpus very small, yellow; proboscis yellow.
Thorax: Black; scutum with delicately greyish microtomentum; proepisternum with greyish microtomentum; anepisternum shining black; anepimeron shining black, with greyish microtomentum on anterior half; katepisternum shining black, with densely greyish microtomentum along upper posterior corner; 1 postpronotal, 2 notopleural, 0+1 supra-alar, 1 postalar, 0+1 dorsocentral setae present; acrostichal and dorsocentral setulae vestigial, scarcely distinguishable; 1 posteromarginal anepisternal seta, 1 seta around posterior spiracle present; scutellum greyish dusted, with strong apical seta and fine, short basal seta (Fig. 1B).
Legs: Fore leg entirely yellow; mid and hind legs with coxae and trochanters yellow, femora dark with bases broadly yellow, knees yellow, tibiae mostly dark but partly yellow apically; fore coxa with 1 preapical dorsal seta; fore femur with 2 black spines ventrally, distal spine curved and subtriangular with apical half much flattened and thickened, and 1 subapical anteroventral seta approximately 3/4 of femur width (Fig. 1C); fore tibia thickened in apical half with protuberance (Fig. 1C); mid and hind femora, and hind tibia without setae; mid tibia with 1 ventral seta in apical third; hind tibia with a large osmeterium anterodorsally, occupying most of basal half of tibia.
Wing: Hyaline, covered with microtrichia; veins light brown; calypter and halter white.
Abdomen: Brownish-black, shining; tergites 4–5 with several marginal setae; sternal appendage as in Fig. 1D, with setae along upper margins, lateral edges abruptly straight. Epandrium and surstylus as in Figs. 1E–F, surstylus simple, without median projections, with some inward-pointing dentation subapically. Phallus as in Figs. 1G–H.
Female. Body length: 3.1–3.4 mm; wing length: 2.2–2.5mm.
Closely resembling the males except for the following: foreleg simple without spines; fore and mid tibiae without ventral seta; hind tibia without osmeterium anterodorsally (Fig. 2).
Etymology. The specific name is derived from the Latin words “angulus,” meaning “angle,” and “spina,” meaning “spine.”
Distribution. Republic of Korea.
Remarks. This new species was collected by sweeping around reed beds along the coastal tidal flats of the western coast of Republic of Korea, where mudflats are well-developed.
description: Published as part of Kim, Dongmin & Kim, Young-Kun, 2025, Two new species of the genus Meroplius Rondani (Diptera: Sepsidae) from Republic of Korea with a key to the Palaearctic species, pp. 561-570 in Zootaxa 5627 (3) on pages 562-565, DOI: 10.11646/zootaxa.5627.3.9, http://zenodo.org/record/15326440