Mixaderus chassaini, Gompel, 2021

Gompel, Nicolas, 2021, New Mixaderus species from the Mascarene Islands (Coleoptera: Aderidae), Zootaxa 4969 (1), pp. 166-174 : 168

Mixaderus chassaini n. sp.

( Figures 1d , 2b,i,r )

Etymology. This species is named in the memory of my late colleague Jacques Chassain, who made several contributions to the systematics of Eucnemidae and Elateridae from the Mascarene islands.

Type locality. France: La Réunion, La Possession, Les Lataniers [20°56’ S 55°21’ E] .

Distribution. France: La Réunion.

Description. Body length. ♂ holotype: 1.60 mm. Body bicolour, head brown, pronotum pale, elytra brown with white stripes. Appendages pale with darker femora.

Head. Transverse, brown, slightly wider than pronotum. Frons flat. Palpi yellow. Punctuation dense, punctures intermediate, comparable to the punctuation near the anterior margin of the pronotum. Pubescence double, dense, wholly, yellow, homogeneous, largely covering the tegument. Eyes interrupting the posterior edge of the head in side view ( Figure 2r ).

Antennae ( Figure 2i ). Thin, a third shorter than elytra, entirely yellow, pubescent. Regularly cylindrical, but apex broader, with antennomeres 9‒10 transverse and antennomere 11 more than twice longer than penultimate.

Pronotum. Convex and sub-quadrate, with a pair of dimples just anterior to the posterior border. Sides weakly but regularly curved. Surface, densely punctuated, the space between punctures smaller than the puncture diameters. Pubescence dense, double, golden anteriorly and white in the posterior third.

Elytra. Length: ♂ holotype: 1.05 mm. Sides weakly convex forming a short oval, with humeral callus well marked. Punctuation strong and deep, but less dense than on the pronotum (space between punctures equivalent to the puncture diameters). Disc slightly convex. Pubescence dense, wholly, golden, comprised of setae borne from the punctuation and interspersed pruinosity, with a distinct pattern of white pubescence on the elytra, formed of four elements on each side: a weak and small humeral spot, a broad uninterrupted anterior transversal band at the level of the disc, broadening on the elytral disc, a second, posterior uninterrupted transversal band on the declivity, curved and irregular, and a broad mark at the apex, confluent with the second band.

Legs. Simple (no apparent sexual characters), tarsae and tibiae yellow, femora dark orange.

Aedeagus ( Figure 2b ). Progressively and regularly tapered from base to apex. Large accessory lobes emerging from the apicale, half-way between base and apex, extending beyond apical tip of the phallus, ending in a spatula shape with four long bristles.

Type material. France: La Réunion: La Possession, Les Lataniers , (110 m) [20°56’ S 55°21’ E], 6.III.2013, Battage bois d’olive, V. Legros leg. (1 ♂ holotype, MHNRUN) .

Figures

FIGURE 1. Habitus of new species of Aderidae from the Mascarene Islands. a, Mixaderus reunionensis n. sp. (♂ holotype from La Réunion); b, Mixaderus tamisieri n. sp. (♂ paratype from La Réunion); c, Mixaderus mauritiensis n. sp. (♀ holotype from Mauritius); d, Mixaderus chassaini n. sp. (♂ holotype from La Réunion); e, Mixaderus lemagneni n. sp. (♂ paratype from La Réunion); f, Mixaderus voisini n. sp. (♀ paratype from La Réunion). Scale bars: 0.5 mm.

FIGURE 2. Anatomy of new species of Aderidae from the Mascarene Islands. a–g: aedeagus of a, Mixaderus reunionensis n. sp. (♂ holotype from La Réunion); b, Mixaderus chassaini n. sp. (♂ holotype from La Réunion); c, Mixaderus tamisieri n. sp. (♂ paratype from La Réunion); d, Mixaderus lemagneni n. sp. (♂ paratype from La Réunion); e, Mixaderus gomyi Gompel, 2012 (♂ holotype from La Réunion); f–g, Mixaderus voisini n. sp.: f, anterior struts retracted (♂ holotype from La Réunion); g, anterior struts extended from phallobase (♂ paratype from La Réunion). h–o: antennae of h, Mixaderus reunionensis n. sp. (♂ holotype from La Réunion); i, Mixaderus chassaini n. sp. (♂ holotype from La Réunion); j, Mixaderus tamisieri n. sp. (♂ paratype from La Réunion); k, Mixaderus lemagneni n. sp. (♂ paratype from La Réunion); l, Mixaderus gomyi Gompel, 2012 (♂ holotype from La Réunion); m, Mixaderus mauritiensis n. sp. (♀ holotype from Mauritius); n, Mixaderus voisini n. sp. (♀ paratype from La Réunion). o,p: male right prothoracic tarsae of o, Mixaderus gomyi Gompel, 2012 (♂ holotype from La Réun- ion); p, Mixaderus lemagneni n. sp. (♂ paratype from La Réunion). q–v: Mixaderus head schematics in side view. q, Mixaderus reunionensis n. sp.; r, Mixaderus chassaini n. sp.; s, Mixaderus tamisieri n. sp.; t, Mixaderus lemagneni n. sp.; u, Mixaderus voisini n. sp.; v, Mixaderus mauritiensis n. sp. Scale bars: 0.1 mm.