Eupines (Byraxis) decens (Broun, 1893)

Shen, Jia-Wei & Leschen, Richard A. B., 2020, Revision of Eupines King of New Zealand (Coleoptera: Staphylinidae: Pselaphinae: Goniaceritae), Zootaxa 4777 (1), pp. 1-84 : 23-24

Eupines (Byraxis) decens (Broun, 1893)

Fig. 13 ; map Fig. 50

Bryaxis decens Broun, 1893a: 1046 .

Eupines (Byraxis) decens : combination and subgeneric assignment by Raffray 1904: 207. Raffray 1911: 83, 1924: 157; Hudson 1923: 364, 1934: 183; Nomura and Leschen 2006: 254; Maddison 2010: 417; Shen and Leschen 2019: 264 .

Type locality: [AK] Paparoa, near Howick.

Type depository: BMNH LT ♂, 1 PLT .

Diagnosis: Head with vertexal foveae asetose and small; antennae 10-segmented with 2-segmented antennal club; A4, A5, A6, A7 and A8 unmodified, A9 largest, basally concave at inner side in dorsal view, with spine in small lateral apical excavation, A10 conical in dorsal view and flattened in lateral view, with long lateral subapical spine. Abdominal ventrite 2 with pair of small and nude discal protuberances; ventrite 6 with pair of long median struts, slightly longer than half of ventral length. Protrochanters with long ventral spine, about as long as protrochanteral width; protibiae and mesotibiae unmodified.

Redescription: Body length 1.32–1.36 mm; body colour dark brown with lighter coloured elytra and legs. Head wider than long; frons slightly narrowed at end, about three-fifths width of head at eye level; eyes well de- veloped and prominent, with about 32 facets; vertexal foveae asetose and small; antennal tubercles barely visible; postantennal notches punctiform; postantennal cavities medium-sized in dorsal view, slightly longer than half length of antennal tubercles in dorsal view; antennae 10-segmented with 2-segmented antennal club; A4, A5, A6, A7 and A8 unmodified, A9 largest, basally concave at inner side in dorsal view, with spine in small lateral apical excavation, A10 conical in dorsal view and flattened in lateral view, with long lateral subapical spine. Pronotum as long as wide, slightly narrower than head at eye level; lacking lateral antebasal foveae. Elytra as long as wide, widest at apical two-thirds; humeral calli moderately developed; sutural stria shallowly extending from base to apex. Abdomen with tergite 1 about 1.5 × longer than tergite 2; ventrite 2 with pair of small and nude discal protuberances; ventrite 6 with pair of long median struts, slightly longer than half of ventral length. Legs with protrochanters modified with long ventral spine, about as long as protrochanteral width; protibiae and mesotibiae unmodified. Aedeagus about 0.30 mm long, with slender and slightly asymmetric parameres curved inwards, with pair of short apical setae; median lobe with two long sclerites, wide near base and gradually convergent towards apex, both curved inwards in dorsal view, left one longer and more curved than right one.

Comments: This species is similar to E. (B.) petila by its similarly modified A10. However, the strongly asymmetrical aedeagus and long median struts of ventrite 6 of E. (B.) decens ( Figs. 13 G–J) can immediately separate it from E. (B.) petila .

Distribution: North Island. AK, CL.

Additional material examined: 4 ♂♂, AK: 1, Ex. Broun Collection, Hunua Ra., Maketu, Auckland, Byraxis decens Broun, T. Broun Collection, A. E. Brookes Collection; 1, Coll. A. E. Brookes, Hunua Ra., Drury, 1/1/1916, 1870, Byraxis decens Broun., Var. A. E. Brookes Collection; CL: 2, Ex. Broun Collection, Tairua, E. coast, North Is., 1870, Byraxis decens Broun, T. Broun Collection, A. E. Brookes Collection.

Figures

FIGURE 13. Diagnostic characters of E. (B.) decens (Broun, 1893). A) Habitus. B) Antenna, in dorsal view. C) Same, in lateral view. D) Same, in ventral view. E) Protrochanter. F) Ventrite 2. G) Ventrite 6. H) Aedeagus, in dorsal view. I) Same, in lateral view. J) Same, in ventral view. Scale bars: A = 1 mm, B–F = 0.2 mm, G–J = 0.1 mm.

FIGURE 50. Geographic distributions of E. (B.) crassicornides Newton, 2017, E. (B.) decens (Broun, 1893), E. (B.) dispar (Sharp, 1874), E. (B.) dugdalei sp. n., E. (B.) fraudulenta (Broun, 1886) and E. (B.) gigas sp. n. in New Zealand.