Allometopon hesperotoxon Lonsdale, 2016, spec. nov.
Creators: name: Owen Lonsdale
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Clusiidae
Allometopon
Allometopon hesperotoxon

description: Allometopon hesperotoxon spec. nov.
Figs 100–106, 335
Description. General: Body length 3.4–4.5mm. Arista short plumose. M1+2 ratio 3.0–3.7. First flagellomere circular to slightly enlarged. Female clypeus relatively broad.
Chaetotaxy: Three fronto-orbital setae (anterior seta shorter). Ocellar seta well-developed. Postvertical absent (small in Johor female). Interfrontal seta small but well-developed. First flagellomere along margin with hairs longer than width of base of arista. Anterior dorsocentral half length of posterior seta; closely set posteriorly. Acrostichal seta present. One lateral scutellar seta.
Colour—male: (Figs 101, 102) Setae yellow. First flagellomere light yellow, brown dorsal stripe vestigial to absent; frons yellow with ocellar tubercle dark brown; gena, parafacial and postgena white and tomentose, lower margin of gena and inner margin of parafacial shiny and brownish; distal third of palpus dark brown; clypeus brownish dorsally and laterally; back of head yellow. Notum entirely yellow. Pleuron, coxae and base of femora yellowish-white with dark anepisternal spot; remainder of legs yellow. Halter white. Wing dusky along R2+3 past R1. Abdomen brown dorsomedially with tergite 1 yellow aside from brown distal margin, and cercus and surstylus white.
Colour—female: (Figs 100, 103) As described for male except as follows: setae light brown; dorsal stripe on antenna pronounced to slightly faded; midline of frons with orange or brown stripe; clypeus yellowish-orange; back of head with small brown spot below ocelli. Scutum yellow with brown lateral stripe behind light yellow postpronotum and medial stripe that tapers past suture to a point; anterior margin of scutum narrowly brown; scutellum brown, yellowish at base of apical scutellars in one female; metanotum brown with mediotergite slightly paler. Wing slightly darker. Abdomen brown on tergites 2–6 with lateral margin yellowish; remainder yellow excluding white cercus, and tergite 7 light brown with dorsomedial surface yellow. Malaysian females differ as follows: colour darker; back of head with one pair of stripes radiating from foramen that is only dark along lateral margin; posterolateral corner of frons brown to base of outer vertical; postpronotum brown; anterior margin of scutum more broadly brown, medial and lateral stripes confluent anteriorly; one female with tergite 6 mostly yellow dorsally and anterolaterally.
Male terminalia: (Figs 104–106) Externally as described for A. eotoxon, except basal lobe not tuberculate, anterobasal process broadly rounded, and surstylus thinner medially and more sharply truncated apically. Ventral lobe of hypandrium with two setae, apparently fused into very long hypandrial arm. Phallapodeme rod-like, welldeveloped and with ventral shield broad, projecting and dome-like. Pregonite large, round, weakly sclerotized and with several medial setae. Postgonite very small and rounded. Basiphallus well-developed. Epiphallus very small and thin. Distiphallus half length of phallapodeme. Paraphallus well-developed with thin basal “thumb” (similar to Sobarocephala).
Female terminalia: (Fig. 335) Spermatheca spherical and dark with small, clear disc at base bearing numerous minute papillae; duct many times length of spermatheca. Ventral receptacle well-developed with short flagellum.
Etymology: The specific epithet compounds the Greek for "bow" (toxon), referring to the shape of the surstylus, and the Greek for west (hesperos) refers to the distribution of this taxon with respect to its sister species, A. eotoxon.
Distribution: Indonesia (North Kalimantan), Malaysia (Johor, Pahang).
Holotype: INDONESIA. North Kalimantan Prov.: E. Kalimanto, Kac., Pojungan Kayan-Mentorang Nat. Res., [03°12′N 115°30′E], vi–xii.1993, D.C. Darling, log emergence trap, 2°52′N, 115°49′E, 378m (1♂, MZB).
Paratypes: INDONESIA. Same collection as holotype (1♂, ROME; 1♀, MZB; 1♀, CNC).
Additional material examined: MALAYSIA. Malay Penins: Pahang, F.M.S., Fraser’s Hill, 4200ft., 27.vi.1931, Ex. F.M.S. Museum, B.M. 1955-354 (1♀, BMNH), Johor Gunung Muntahak, 15km NW Kota Tinggi, 26–27.v.2004 /5 (1♀, MHNG).
Comments: The species Allometopon eotoxon (Fig. 52) (Papua New Guinea), A. hesperotoxon (Indonesia (North Kalimantan), Malaysia (Johor, Pahang)) and A. machaeroges (Fig. 157) (Ivory Coast) exhibit highly similar male genitalia including a large, hooked surstylus and are well-supported as monophyletic. Underlying colouration is also similar, especially elements of the notal pattern and the reduction of the brown markings on the back of the head, and the males of both A. hesperotoxon and A. machaeroges are secondarily pale on the frons and notum. While the females of A. hesperotoxon are more similarly patterned to the male of A. eotoxon, recovery of these females with the males of A. hesperotoxon at Kayan Mentarang National Park suggests conspecificity, as does the darker pigment on the head and pleuron.
description: Published as part of Owen Lonsdale, 2016, Revision of the genus Allometopon Kertész (Diptera: Clusiidae), pp. 1-127 in Zootaxa 4106 (1) on pages 32-33, DOI: 10.11646/zootaxa.4106.1.1, http://zenodo.org/record/258766