Byrrhinus angolensis Matsumoto, 2021

Matsumoto, Keita, 2021, New species and records of Angolan Limnichidae (Coleoptera: Byrrhoidea), Zootaxa 4985 (1), pp. 111-117 : 115-117

Byrrhinus angolensis Matsumoto sp. nov. [ Figures 10-12 ]

Type locality. Angola, Cassamba , Luio River .

Type materials. Holotype male, deposited at BMNH “ ANGOLA 1187m, Cassamba , Luio River, 13.19398S, 20.2235E; 30.xi-1.xii.2019, // General Coll. & UV LED, Matsumoto, K. leg. Okavango Wilderness Project, BMNH (E) 2020-30” with unique identification number “NHMUK014383825”. Additional label on red paper added “ Byrrhinus angolensis sp. nov. K. Matsumoto det. 2020 HOLOTYPE ♂ ” . Paratype (2 male; BMNH, AMG) : same locality data as the holotype, with unique identification number “NHMUK014383826” and “NHMUK014375572”.All paratype specimens have been labelled with a red paratype label: “ Byrrhinus angolensis sp. nov. K. Matsumoto det. 2020 PARATYPE ♂ ”.

Description of holotype, male. Body: Elongate, oval, dorsum convex, BL: 1.9 mm, EL: 1.5 mm, EW: 1.1 mm, PL: 0.4 mm, PW: 1.0 mm and HW: 0.5 mm. Colour: Dorsal side black; venter brown to dark reddish brown, tibia brown, tarsal claws brown. Dorsal and ventral surface densely covered with setae.

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Dorsum. Head: Partially retracted into pronotum; overall surface smooth, no punctation across surface. Antennae: 11 segmented, filiform, fully pubescent, antennomeres long and slender, 1st AS widest, 2nd AS slightly narrower than 1st AS, 3rd to 6th AS long and thin, 7th to 11th AS skewed oval. Pronotum: Transverse, widest at posterior, narrowest at anterior, narrower than elytra; anterior margin concave, posterior margin strongly sinuate; lateral margin nearly straight; surface covered with moderately dense punctation, surface between punctures smooth and shiny. Scutellum: Subtriangular, large, lateral sides slightly convex. Elytra: Longer than wide; anterior margin sinuate; anterior lateral angle obtuse; lateral margins gently curve from anterior end to anterior 2/3, increase in curvature towards the apex; surface with small and moderately dense punctuation; punctuation decreases in depth towards the elytral tip; elytral striae not clearly visible; surface between punctures smooth and shiny.

Venter. Overall surface with moderately dense micro-punctures with setae emerging from the punctures. Prosternum: Concave on anterior margin; prosternal process as long than wide, lateral margin concave, posterior margin semi-oval. Mesoventrite: Wider than long, narrows towards posterior; anterior margin concave where prosternal process fits, discrimen very small; lateral sub-parallel and gently curved, posterior nearly flat, anterior trisinuate. Metaventrite: Wider than long, flat in the middle; discrimen thin and not clearly visible. Abdomen: Five clearly visible ventrites. Intercoxal process sinuate with pointed apex. Posterior margin of 1st and 2nd ventrites convex, 3rd to 4th ventrites slightly concave, 5th ventrite nearly semi-circle. Surface covered with long, light yellow, recumbent setae.

Legs. Tibiae: Outer and inner lateral margin convex. Tarsi: Simple, segments increase in length towards the apex. Tarsal claws: Short, narrow, symmetrical.

Genitalia. Parameres twice as long as median lobe, long and slender, symmetrical, widest as base, apex acute, inner side near the apical end straight. Median lobe apex acute and slightly rounded, base to anterior 0.25 relatively straight, gentle convex curve near the apex. Phallobase strongly asymmetrical. Relatively sclerotised ( Figures 7 ).

Female. Unknown.

Distribution. Byrrhinus angolensis Matsumoto sp. nov. is known only from the type locality ( Figure 14 for habitat).

Etymology. The species named after Angola, where it was collected.

Differential diagnosis. According to the grouping system of Delève (1968), this new species would be in ‘group one’, which has a triangular median lobe and symmetrical parameres. This new species can be distinguished by the inner side near the apical end of the parameres straight, apex of parameres acute, majority of the median lobe straight and parallel.

Figures

Figures 10‒12. Byrrhinus angolensis Matsumoto sp. nov. 10, Dorsal habitus; 11, abdomen; 12, genitalia, ventral

Figures 6‒9. Simplocarina angolensis Matsumoto sp. nov. 6, Dorsal habitus; 7, abdomen; 8, genitalia, ventral; 9, genitalia, lateral.

Figures 13‒14. Limnichidae habitat. 13, Kangumbe, Lungué-Bungo River; 14, Cassamba, near Luio River.