Bibrax arachnoides, Tapuy-Avilés & Díaz-Guevara & Caterino, 2025

Bibrax arachnoides sp. nov.

Figs 5 E, F View Figure 5 , 7 A – D View Figure 7

Type material.

Holotype • ♂ ( MECN -EN 40778 ): “ Ecuador: Pastaza, -1.4267, -78.0439, Rio Anzu Reserve , 1342 m, 11.XI.2024, M. Caterino, sifted litter ” / “ Caterino DNA voucher, Ext. MSC-13131, Morphosp. RAn.014 ” / “ MECN -EN 40778 ” GoogleMaps . Paratypes (6 ♂, 1 ♀) • Ecuador: Pastaza, Sumak Kawsay in situ Reserve , 26-JAN-2024, Díaz-Guevara ( MECN -EN 23781 -23787)

Diagnosis.

BL = 1.68 mm (4). Body densely setose, densely and finely punctate beneath; head rounded at base, vertexal foveae shallowly impressed, short vertexal tubercles present at base; frons narrowing and rising to common antennal base, with shallow median sulcus on surface; eyes (of male) strongly reduced, comprising short longitudinal series of two or three indistinct facets; gular teeth well-developed; antennae with scape very long, slightly sinuate, antennomere II (pedicel) slightly longer than II – V combined, in male slightly convex on outer margin, produced at inner apical corner, III – VIII all bead-like, but V and VII larger and bearing elongate setae, IX – XI forming loose club, X and XI slightly more closely associated than IX and X; pronotum elongate, ~ 1.25 × longer than wide, widest near front, sides rounded; pronotal disk with lateral and median subbasal foveae; disk with only weak lateral longitudinal impressions; elytra rather short (wingless), humeri evenly sloped, sides rounded, each elytron with sutural and lateral basal foveae, lateral fovea with strong impression running posterad ~ 1 / 3 elytron length; subhumeral fovea absent; protibia swollen; male metatrochanter with inner margin expanded, subquadrate, distal corner projecting perpendicularly as small, truncate tooth; last male abdominal ventrite weakly depressed, bearing small basal marginal tooth and larger median apical marginal flange; penultimate male ventrite not obviously modified. Aedeagus (Fig. 5 E, F View Figure 5 ) with subspherical basal bulb, bearing large, round dorsal diaphragm; basal apodemes paired, thin, slightly curved; tegmen short, widened from base to middle, sclerotized portion bent strongly ventrad into a hook with deeply divided, densely bristled lobes extending laterodistad; between them an unsclerotized, setose median lobe extends from tip.

Distribution.

This species is known from two localities in the foothills of the Andes, in western Pastaza Province, Ecuador.

Remarks.

This species and the next two are very similar and share the probable synapomorphy of a swollen antennomere II. They may share this synapomorphy with B. chullachaqui , which is otherwise quite distinct in its large eyes, short body setae, and various other characters. Bibrax arachnoides has slightly different modifications of the last male abdominal ventrite (with a small basal tooth), metatrochanter (more generally subquadrate along apical margin with a perpendicular distal tooth), and antennomere II (more or less symmetrically swollen). The male genitalia of all these species are unambiguously distinct.

Etymology.

We name this species for the somewhat spider-like appearance, common to members of Bibrax , as a result of their geniculate antennae appearing to be an extra pair of legs.