Taxonomy of ' Euconnus complex'. Part IV. Review of Euconnus subgenus Rhomboconnus (Coleoptera, Staphylinidae, Scydmaeninae) Author Jaloszynski, Pawel text Zootaxa 2015 2015-08-18 4000 4 483 491 journal article 10.11646/zootaxa.4000.4.7 17d81de0-fe4f-4bc7-94d0-9fb901527c2d 1175-5326 235208 F07361D4-B606-4525-8E3B-EAE848AB70FB Euconnus ( Rhomboconnus ) trianguliceps Franz ( Figs 3 , 10–11 , 13, 14 b) Euconnus ( Nudatoconnus ) trianguliceps Franz, 1980 : 123 , fig. 101. Euconnus ( Rhomboconnus ) trianguliceps Franz; 1986 : 20. Type material studied. Holotype : Ecuador (Guayas Prov.): ♂, four labels ( Fig. 13 ): "Ingenio San Carlos / b.Guayaquil,VIII,1975 / Ecuador ,lg.H.Franz" with "SA243" on the reverse side [white, printed; reverse handwritten in black], " Euconnus / trianguliceps m. / det.H.Franz" [white, handwritten and printed], " Holotypus " [red, handwritten], " Rhomboconnus / trianguliceps / m. / det.H.Franz" [white, handwritten and printed] ( NHMW ). Revised diagnosis. Head about as long as pronotum; BL < 2.2 mm ; pronotum and elytra with very short and recumbent, barely noticeable setae; pronotum broadest slightly anterior to base, with strongly rounded sides and with pair of small lateral antebasal pits. Redescription. Body of male ( Fig. 3 ) strongly convex, elongate, with long appendages, BL 2.01 mm ; cuticle glossy, uniformly dark brown with slightly lighter legs and palps; vestiture barely noticeable. Head rhomboidal and strongly elongate, broadest at eyes, HL 0.45 mm , HW 0.38 mm ; vertex and frons confluent, evenly convex except frons in front of eyes which is steeply declined anteriorly, posterior margin of vertex nearly straight and slightly broader than 1/3 of HW, slightly raised; supraantennal tubercles absent; eyes large, oval, finely faceted and not projecting from silhouette of head. Punctures on vertex and frons very fine and inconspicuous; setae very short and sparse, recumbent, additionally posterior part of each temple with oblique row of several long bristles and behind them dense tuft of similar, but curved or waving bristles (only partly preserved in holotype ). Antennae slender, AnL 1.30 mm ; all antennomeres except III distinctly elongate, antennomere III about as long as broad, antennomere XI slightly shorter than IX–X together, about twice as long as broad. Pronotum in dorsal view subtrapezoidal with rounded sides, broadest near posterior third but only slightly narrowing caudad, PL 0.44 mm , PW 0.53 mm ; base with shallow and small pit at each side, close to posterior pronotal margin. Punctures and setae on pronotal disc as fine and inconspicuous as those on frons and vertex, sides of pronotum near each posterior corner with remnants of thick bristles, in holotype visible only in lateral view. Elytra suboval, broadest near middle, EL 1.13 mm , EW 0.83 mm , EI 1.36; apices separately rounded. Punctures and setae on elytral disc as fine and inconspicuous as those on head and pronotum. Legs long and slender; unmodified. Aedeagus ( Figs 10–11 ) stout, AeL 0.33 mm , median lobe in ventral view drop-shaped; ventral apical projection broadened near base and strongly narrowing distally; endophallus with assemblage of darkly sclerotized components located at base of ventral apical projection; parameres not reaching apex of median lobe, slender, each with three robust setae. Female. Unknown. Distribution. South-western Ecuador ( Fig. 14 b). Remarks. This species externally only remotely resembles the type species of Rhomboconnus , i.e., E. perplexus . Its head is more slender, pronotum has different shape and bears shallow antebasal pits, the elytra have traces of basal foveae, and the pronotum and elytra are covered with only very short and recumbent, barely noticeable setae. However, the fine structures of the head, including posterior tufts of bristles and ventral characters are similar in both species, and their aedeagi are strikingly similar, so that only the shape of the aedeagal ventral apical projection and some internal details are different.