Colonus gracilis, Rubio & Stolar & Baigorria & Baptista, 2023

Colonus gracilis View in CoL sp. n.

( Fig. 1-7; 10, 12, 14; 27-28)

ZooBank: http://zoobank.org/ DE61CBCB-EF2F-4978-AF82-D7188FFD74FB

Holotype, ♂ ( IBSI-Ar 01297 ), INTA Experimental Station (S27.6575°, W55.4374°, 283 m a.s.l.), Cerro Azul, Misiones, Argentina, 22/X/2018, coll. C.E. Stolar. GoogleMaps

Paratype, 1♀ ( IBSI-Ar 01946 ), [same data as holotype] GoogleMaps .

Diagnosis. – Male of C. gracilis sp. n. resembles C. melanogaster , and C. pallidus and C. robustus to a lesser extent by the general palp aspect, especially in retrolateral view of the vRTA ( Fig. 2-3; compare with Rubio & Baigorria, 2016: Fig. 3 e-f, h-i and Pett et al., 2021: Fig. 6 E-F). It can be distinguished from the former species by having a vRTA with a twist and curvature at the tip that directs it to the retrolateral side, and by having a generally slenderer body, notable especially in the width of the carapace and the relationship of its edges with the PLE ( Fig. 1; compare with Pett et al., 2021: Fig. 6D). In addition, the chelicerae paturon of C. gracilis sp. n. has dark mahogany to black integument (vs. pale in C. melanogaster ). Colonus gracilis sp. n. differs from C. pallidus and C. robustus by having a shorter, twisted and curved vRTA, with the tip directed retrolaterally ( Fig. 2-3). Female of C. gracilis sp. n. is very similar to those of C. melanogaster by the structures of the epigyne ( Fig.5-7; compare with Fig. 11-14 in this paper), but can be distinguished from this by having the border of the CO less sclerotized, each atrium (At) longer than wide, the lateral pouch (LP) directed more anteriorly, and the second stretch of the CD widest (indicated with an asterisk). Additionally, the female carapace (C) of C. gracilis sp. n. is slenderer than that of C. melanogaster (notable especially in the relationship with its edges and the PLE). See the comparison of figures 9-10, 11-12 and 13-14.

Etymology. – The specific name refers to the slender cephalothorax and abdomen of this species (Latin gracilis = slender); adjective.