Euconnus (Rhomboconnus) meteti, Jałoszyński, 2017

Jałoszyński, Paweł, 2017, Euconnus (Rhomboconnus) of Panama (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4323 (1) : -

Euconnus (Rhomboconnus) meteti sp. n.

( Figs 6 , 14 , 35–36, 43–44, 54)

Holotype: Panama (Darién Province): ♂, two labels: " PANAMA, Meteti / 11/08/2014 / 8,465°N, 77,970°W, / litter layer, leg. Tim Struyve" [white, printed], " EUCONNUS / ( RHOMBOCONNUS ) / meteti m. / P. Jałoszyński, '17 / HOLOTYPUS " [red, printed] ( MNHW).

Diagnosis. BL ~ 1.5 mm; head with short and weakly suberect but distinct setae, pronotum and elytra appear asetose, their vestiture composed of very short and recumbent inconspicuous setae; tempora strongly narrowing posteriorly with very short, barely discernible posterior portion bent mesally, which is not visible in dorsal view; pronotum broadest between middle and posterior third and strongly narrowed posteriorly and anteriorly; pronotal base with indistinct, faint transverse groove connecting a pair of small but distinct lateral pits; parameres not broadened in subapical region.

Description. Body of male ( Fig. 6 ) strongly convex, elongate, with moderately long appendages, BL 1.54 mm; cuticle glossy, uniformly dark brown, vestiture slightly lighter than cuticle.

Head ( Fig. 14 ) strongly narrowing posteriorly, broadest at eyes, HL 0.26 mm, HW 0.30 mm; vertex and frons confluent, evenly and relatively strongly convex except frons in front of eyes which steeply declines anteriorly, posterior margin of vertex projecting posteriorly as subtrapezoidal lobe slightly broader than 1/3 of HW; tempora indistinctly convex with extremely short, barely noticeable posterior portion bent posteromesally, which is visible only in lateral or dorsolateral view; supraantennal tubercles barely marked; eyes large, finely faceted and weakly projecting from silhouette of head. Punctures on vertex and frons very fine and inconspicuous; setae moderately long and dense, only slightly suberect but well visible; tempora laterally with sparse long bristles. Antennae slender, AnL 1.15 mm; all antennomeres except III elongate, III indistinctly transverse; antennomeres VII–XI forming indistinctly delimited club, antennomere XI much shorter than IX and X combined, ~2.3 times as long as broad, slightly flattened.

Pronotum ( Fig. 14 ) in dorsal view broadest between middle and posterior third, strongly narrowing anteriorly and posteriorly, PL 0.35 mm, PW 0.44 mm; base with faint transverse groove connecting lateral pair of small and shallow but distinct pits. Punctures as fine as those on frons and vertex, pronotal disc covered sparsely with barely discernible short and recumbent setae; sides with bristles.

Elytra suboval, broadest near middle, EL 0.93 mm, EW 0.73 mm, EI 1.28; apices separately rounded. Punctures and setae similar to those on pronotal disc.

Legs moderately long and slender; protrochanter with distinctly projecting distoventral corner forming small pointed tooth.

Aedeagus (Figs 35–36, 43–44) stout, AeL 0.38 mm, in ventral view drop-shaped with lateral margins gradually convergent toward apex; endophallus with three long and one short sclerites ( Fig. 54 ), of which the median one has its apical portion rapidly narrowed and developed as a short and pointed apical projection; parameres not broadened in subapical region.

Female. Unknown.

Distribution. Eastern Panama, Darién Province, Pinogana District.

Etymology. Locotypical, after the corregimiento (i.e., the smallest administrative division) Meteti in Panama (noun in apposition).

Remarks. Euconnus meteti is the smallest known Rhomboconnus , with BL 1.54 mm, whereas the second smallest species, E. plaumannioloides , is distinctly larger, with BL 1.75–1.76 mm. Euconnus meteti can be distinguished from all remaining species of Rhomboconnus also on the basis of its distinctly setose head and very finely setose pronotum and elytra, which are covered with so short and recumbent setae that that may be difficult to notice at magnification 80×. Moreover, E. meteti has a faint transverse antebasal pronotal groove with a small but distinct pit at each end ( Fig. 14 ), and the head shorter than pronotum (all remaining species have the HL/PL index equal to or higher than 1, see Table 1).

Figures

FIGURES 1 – 8. Dorsal habitus of Rhomboconnus species, males. Euconnus plaumannioloides sp. n. (1); E. timstruyvei sp. n. (2); E. silvafortunensis sp. n. (3); E. rhombopanamensis sp. n. (4); E. rhombocartianus sp. n. (5); E. meteti sp. n. (6); E. rhombomiramaranus sp. n. (7); E. rhomboimitator sp. n. (8).

FIGURES 9 – 16. Head and pronotum of Rhomboconnus species, males, in strictly dorsal view. Euconnus plaumannioloides sp. n. (9); E. timstruyvei sp. n. (10); E. silvafortunensis sp. n. (11); E. rhombopanamensis sp. n. (12); E. rhombocartianus sp. n. (13); E. meteti sp. n. (14); E. rhombomiramaranus sp. n. (15); E. rhomboimitator sp. n. (16).

FIGURES 49 – 56. Endophallic sclerites of Rhomboconnus species in ventral view (not to the same scale). Euconnus plaumannioloides sp. n. (49); E. timstruyvei sp. n. (50); E. silvafortunensis sp. n. (51); E. rhombopanamensis sp. n. (52); E. rhombocartianus sp. n. (53); E. meteti sp. n. (54); E. rhombomiramaranus sp. n. (55); E. rhomboimitator sp. n. (56).