Euconnus (Rhomboconnus) oaxacanus, Jałoszyński, 2020

Jałoszyński, Paweł, 2020, Euconnus (Rhomboconnus): redescriptions of species described by Schaufuss and Sharp, and descriptions of five new Mexican species (Coleoptera, Staphylinidae Scydmaeninae), Zootaxa 4759 (2), pp. 209-222 : 216-218

Euconnus (Rhomboconnus) oaxacanus sp. n.

( Figs 5 , 12 , 34–38 )

Holotype: Mexico (Oaxaca State): ♂, three labels: “ MEXICO: Oaxaca / Café Carlota, 1041 m / 18.04773 - 96.68953 / 14 Jun 2016, R. S. Anderson / 2016-145 liquidambar/cloud forest” [white, printed], white registration label with micro QR code and collection No. UTCI 000017448 , “ EUCONNUS / ( RHOMBOCONNUS ) / oaxacanus m. / P. Jałoszyński, 2020 / HOLOTYPUS ” [red, printed] ( UTCI) . Paratype: 1 ♀, same data as for holotype, except for 1035 m, 18.04791, -96.69076, and coll. No. UTCI 000016791 ( UTCI) .

Diagnosis. Head in male slender, with narrowly projecting and nearly straight posterior margin of vertex; tempora nearly straight but with distinct short expansion slightly in front of middle; pronotum nearly barrel-shaped, indistinctly broader than long and broadest slightly behind middle, with sharply marked transverse antebasal groove distinctly deepened at each end and with distinct, short sublateral carinae; dorsum sparsely setose; antennomeres VIII and X about as long as broad and IX slightly transverse; aedeagus with ventral plate in distal half gradually narrowing toward apex and slightly curved; endophallus with long and broad sclerites, of which the longest is pointed at apex, with nearly symmetrical distal half.

Description. Body of male ( Fig. 5 ) strongly convex, elongate, with moderately long and slender appendages, BL 2.20 mm; cuticle glossy, dark brown with reddish hue, vestiture slightly lighter than cuticle.

Head ( Fig. 12 ) slender, strongly narrowing posteriorly, broadest at eyes, HL 0.48 mm, HW 0.38 mm; vertex and frons confluent, together evenly convex, posterior margin of vertex short and nearly straight; tempora nearly straight except for a short expanded and convex portion slightly in front of middle, nearly 5 × as long as eyes in dorsal view; supraantennal tubercles barely marked; eyes moderately large, finely faceted and weakly projecting from silhouette of head. Punctures on vertex and frons fine and inconspicuous; setae sparse but relatively numerous, moderately long and suberect with admixture of shorter and nearly recumbent setae, especially in posterior half of head, additionally posterior portion of each temple and posterior margin of vertex with several long and thick bristles. Antennae slender and relatively long, AnL 1.25 mm; antennomeres I–II strongly elongate, III about as long as broad, IV–VII each strongly elongate, VIII about as long as broad, IX slightly transverse, X about as long as broad, XI as long as IX–X together, 2.2 × as long as broad; antennomeres X and XI slightly flattened.

Pronotum ( Fig. 12 ) in dorsal view nearly barrel-shaped, with long anterior margin, broadest slightly behind middle and weakly narrowing anterad, PL 0.48 mm, PW 0.50 mm; sides weakly rounded, anterior margin indistinctly bisinuate, posterior margin nearly straight, base with sharply marked transverse groove connecting tiny lateral pits, and with short and distinct sublateral carinae laterad each pit, extending from base to the level of transverse groove. Punctures inconspicuous; disc sparsely covered with extremely fine, barely discernible and nearly recumbent setae, with several long, suberect setae on anterior half, additionally sides with long and dense thick bristles.

Elytra together suboval, broadest distinctly in front of middle, EL 1.25 mm, EW 0.88 mm, EI 1.43; apices rounded together. Punctures on elytral disc slightly more distinct than those on head and pronotum but superficial and inconspicuous; vestiture with moderately sparse, short and barely discernible nearly recumbent setae and with sparser, much longer and suberect setae similar to those on pronotum.

Legs moderately long and slender; unmodified.

Aedeagus ( Figs 34–38 ) stout, AeL 0.43 mm, in ventral view drop-shaped with apical region rapidly narrowed; endophallus with relatively broad complex of sclerites ( Fig. 38 ), of which the longest is nearly symmetrical with slender, pointed apex; parameres slender, each with three long apical and subapical setae.

Female. Externally similar to male, but with slightly smaller, round eyes. BL 2.25 mm; HL 0.50 mm, HW 0.38 mm, AnL 1.23 mm; PL 0.50 mm, PW 0.53 mm; EL 1.25 mm, EW 0.88 mm, EI 1.43.

Distribution. Southern Mexico.

Etymology. After the Mexican Free and Sovereign State of Oaxaca.

Remarks. Euconnus oaxacanus can be distinguished from all species of Rhomboconnus solely by the lateral expansion on otherwise nearly straight tempora.

Figures

FIGURES 1–8. Dorsal (1–3, 5–8) and lateral (4) habitus of Euconnus (Rhomboconnus). Euconnus cavifrons (L.W. Schaufuss) (1); E. giraffa Sharp (2); E. agiraffa sp. n. (3–4); E. oaxacanus sp. n. (5); E. bicarinatus sp. n. (6); E. cordobanus sp. n. (7); E. maya sp. n. (8).

FIGURES 9–15. Head and pronotum of Euconnus (Rhomboconnus) in dorsal view. Euconnus cavifrons (L.W. Schaufuss) (9); E. giraffa Sharp (10); E. agiraffa sp. n. (11); E. oaxacanus sp. n. (12); E. bicarinatus sp. n. (13); E. cordobanus sp. n. (14); E. maya sp. n. (15). Abbreviations: ami, anteromedian impression; abg, antebasal groove; abp, antebasal pit; slc, sublateral carina.

FIGURES 34–43. Aedeagus in ventral (34, 36, 39, 41) and lateral (35, 37, 40, 42) views, and endophallic sclerites in ventral view (38, 43) of Euconnus (Rhomboconnus). Euconnus oaxacanus sp. n. (34–38); E. bicarinatus sp. n. (39–43).