Allometopon geniculatum (Sasakawa) Sasakawa, 2016

Owen Lonsdale, 2016, Revision of the genus Allometopon Kertész (Diptera: Clusiidae), Zootaxa 4106 (1), pp. 1-127 : 27-28

publication ID	https://doi.org/ 10.11646/zootaxa.4106.1.1
publication LSID	lsid:zoobank.org:pub:A5ADF236-5219-4014-9DC4-C43F981DD1A4
DOI	https://doi.org/10.5281/zenodo.3510928
persistent identifier	https://treatment.plazi.org/id/6866497B-F10D-346F-FF39-A7C1F17FFCBB
treatment provided by	Plazi
scientific name	Allometopon geniculatum (Sasakawa)
status	comb. nov.

Treatment

Allometopon geniculatum (Sasakawa) COMB. NOV.

Figs 74–79 View FIGURES 74 – 79

Sobarocephala geniculata Sasakawa, 2011: 11 View in CoL View Cited Treatment . Lonsdale 2014: 220 View Cited Treatment .

Description. General: ( Figs 74, 75 View FIGURES 74 – 79 ) Body length 3.0– 3.6mm. M1+2 ratio approximately 2.3. Type specimens in poor condition with aristae, first flagellomeres, most setae and halters missing. Female unknown.

Chaetotaxy: Setae partially evident from sockets: three fronto-orbitals, interfrontals not evident, two dorsocentral setae (closely spaced posteriorly), one pair of lateral scutellar setae; acrostichal and presutural intraalar setae absent.

Colour: Setae brownish-yellow. Head light yellow, whitish below frons, with antenna yellow, ocellar tubercle brown, and posterior region of postgena and back of head mostly brown above foramen excluding dorsomedial region; parafacial, gena and postgena silvery tomentose. Notum yellow with curved brown stripe along anterior margin of scutum past pronotum, metanotum brownish with katatergite brown, and scutellum light yellow; floating postsutural intra-alar stripes possibe artifact of preservation. Pleuron mostly light yellow, contrasting slightly darker scutum which may only differ due to state of preservation; anepisternum with large dark brown spot. Legs yellow. Halter yellow. Wing with faint anterodistal infuscation. Abdomen of paratype dark brown; abdomen of holotype (from Sasakawa (2011)) with “T1, T2 and anterior half of T3 yellowish-brown, posterior half of T3, T4–6, and S8 black; epandrium shining black, surstylus pale brown”.

Male terminalia: ( Figs 76–79 View FIGURES 74 – 79 ) Surstylus approximately as high as epandrium, thin and sharply angled on distal 1/3 with tubercle-like setae on inner-ventral margin; outer surface setose medially. Cerci small, short-haired and slightly divergent. Hypandrium with well-developed arm and moderately developed, rounded and bare ventral lobe. Pregonite membranous with several setae. Postgonite small and weakly sclerotized with several setae. Basiphallus relatively flattened; epiphallus present as minute distoventral point. Distiphallus narrow, pointed, minutely textured. Paraphallus subequal to distiphallus, tapered apically and minutely spinulose along dorsal surface.

Distribution: Thailand.

Holotype: THAILAND. Chiangmai: Doi Suthep, 28–31.iii.1958, T.C. Maa [Type No. 17245] (1♂ BPBM).

Paratype: THAILAND. Chiangdao, 5–11.iv.1958, T.C. Maa (1♂, BPBM).

Comments: Generic placement of Sobarocephala geniculata was considered uncertain by Lonsdale (2014), who suggested that it might belong to Allometopon , but was not certain given the poor condition of the available material. Following more thorough examination of this genus, it is now certain that this alternate generic placement is correct and the species is formally recombined here.

Similarities in colouration (notum yellow with anterior margin of scutum brown, anepisternum with large brown spot, stripes behind head confluent dorsomedially) and structure of the male genitalia (surstylus shape, small pregonite and postgonite, structure of hypandrium, distiphallus and paraphallus) suggest an association with A. lux ( Fig. 143 View FIGURES 143 – 147 ) ( Philippines), also unfortunately represented by material in poor condition, and the putative sister species A. giallo ( Fig. 80 View FIGURES 80 – 84 ) ( Vietnam) and A. grypostylis ( Fig. 90 View FIGURES 90 – 94 ) ( Laos, Thailand). Allometopon lux differs in having a clear wing, a slightly thicker surstylus with a straighter apex, and a long, ill-defined pregonite that is broad along the anterior margin. Allometopon giallo and A. grypostylis also have a similar gracile surstylus, but its apex is more gradually curved, the ventral lobe of the hypandrium is short and subtriangular with two distal setae, the pregonite is large and subtriangular with a cluster of setae posterodorsally and the scutellum is brown.