Obrieniolus, a new monotypic genus of Naupactini (Coleoptera, Curculionidae, Entiminae) from the Peruvian Andes and its phylogenetic placement

Abstract A new monotypic genus of Naupactini (Coleoptera: Curculionidae), Obrieniolus del Río is described based on the new species Obrieniolus robustus del Río, endemic to Peru. This genus is easily recognized by the black, denuded and shiny integument, with imbricate microsculpture and the rounded body, with short, cordiform and moderately convex elytra. According to a cladistic analysis based on 69 continuous and discrete morphological characters, the new genus is the sister taxon of a group formed by Amitrus Schoenherr, Trichocyphus Heller, Amphideritus Schoenherr, Asymmathetes Wibmer & O’Brien and Galapaganus Lanteri. The paper includes habitus photographs, line drawings of genitalia, mouthparts, and other external features of taxonomic value, and a dichotomous key to the genera of Naupactini distributed in the South American Transition Zone.

In the present contribution we describe a new Andean genus and species which cannot be accommodated within any of the existing weevil genera. This new monotypic taxon is endemic to Peru and ranges throughout the Puna province, mainly characterized by a shrublike steppe, with bushes 40 to 150 cm high. A cladistic analysis was performed to analyze the relationship of the new genus with other Naupactini from the Andes and the Pacific coastal deserts, a monophyletic clade within this tribe (del Río and Lanteri unpublished).

Materials and methods
The material studied comes only from the Charles W. O´Brien personal collection (CWOB). The holotype and three paratypes have been returned to CWOB collection, and one paratype has been deposited in the Museo de La Plata collection (MLP).
Dissections of female and male genitalia were done according to standard entomological techniques. Measurements were taken with an ocular micrometer. Abbreviations used in the description are as follows: LB: length of body, measured from apex of rostrum to apex of elytra; WRa: width of rostrum across apex; WRb: width of rostrum at base; LR: length of rostrum from anterior margin of eye to apex; LA: maximum length of antenna; A1: length of funicular article 1; A2: length of funicular article 2; WC: maximum width of club; LC: maximum length of club; WP: maximum width of pronotum; LP: maximum length of pronotum; WE: maximum width of elytra; LE: maximum length of elytra. For line drawings we used a camera lucida adapted to a stereoscopic microscope Nikon MZ1000.
Phylogenetic analysis.  (54) and to the genitalia (10 of females and five of males). Sixteen continuous characters correspond to ranges of ratios between measurements and were treated as such, avoiding the use of ad hoc methods to establish ranges (Goloboff et al. 2008). Multistate characters with intraspecific variation were treated as polymorphic, as indicated in TNT (e.g. [0 1]). All discrete characters were treated as unordered.
Parsimony analysis was performed with the software "Tree Analysis using New Technologies" (TNT) (Goloboff et al. 2003) using the 'traditional' search approach based on 100 replicates using TBR branch swapping, and hold 10. Discrete characters were mapped on the most parsymonious cladogram through Winclada version 1.00.08 (Nixon 2002). Homoplasy was estimated using consistency and retention indices (Kluge and Farris 1969;Farris 1989). Branch support was evaluated by bootstrap (Felsenstein 1985) with 100 replicates, and values over 50% were indicated below each branch (Fig. 14).
The most parsimonious tree was rooted with Mendozella curvispinis, which is the only terminal taxon distributed in the Monte province, belonging to the South American Transition Zone but not to the Paramo-Puna subregion (Lanteri 1989; Lanteri and Morrone 1991).
Etymology. The genus is named after the outstanding weevil specialist Charles W. O´Brien, who loaned us the material for this study.

Remarks.
Obrieniolus is distinguished by the particular shape of the body (cordiform, extremely rounded and short), completely covered with imbricate microsculpture, the strongly separated punctures of the elytral striae, and the bursa copulatrix studded with dense and minute spines directed backwards, near the vagina. Other generic characters are common in most Naupactini inhabiting mountain environments, e.g. the black, denuded and strongly sclerotized integument, the absence of metathoracic wings and the reduced shoulders. Natural history. Obrieniolus seems to be endemic to northeastern Peru, Department of La Libertad, at about 2800 m of elevation. Its distribution corresponds to the Puna biogeographic province, that also extends in eastern Bolivia, northern Argentina and Chile (Morrone 2006), which is a steppe shrublike formation with bushes 40 to 150 cm high. The area where Obrieniolus occur is close to the Coastal Peruvian Desert province, a narrow strip along the Pacific coast from northern Peru to northern Chile (Morrone 2006), characterized by the extremely dry climate.
Obrieniolus robustus was found under rocks, in dry hills with grasses and sparse small shrubs. No specific host plant associations are known. The possibility of parthenogenesis is inferred based on the absence of males. This kind of reproduction seems to be frequent in the Andean species of Naupactini (Lanteri and Normark 1995; del Río 2010).
Legs. Black, naked of scales, with imbricate microsculpture. Front coxae slightly separate, 3x closer to anterior margin than to posterior margin of prosternum (almost reaching anterior margin); protibiae with row of 7-11 acute medium sized denticles and strongly acute mucro; meso and metatibiae without denticles and mucro; metatibial apex with broad outer bevel (placed in whole tibial apex), oblique regarding tibial axis, with small whitish iridescent scales; dorsal comb slightly shorter than apical comb or subequal.

Cladistic analysis: results and discussion
The parsimony analysis resulted in a single most parsimonious cladogram 195.20 steps long, with CI = 0.58 and RI = 0.53 (Fig. 14). Melanocyphus is the sister taxon of the remaining genera, that form a clade justified by eight synapomorphies, such as the narrow epistome (char. 29 The sister clade of Obrieniolus is divided into two groups, one including Trichocyphus and Amitrus, and the other, with Amphideritus, Asymmathetes and Galapaganus. The first group is characterized by the wide intercoxal area of ventrite 1 (char. 10), the very stout antennae (char. 34.1) and the row of setae along the ovipositor, on the external side of baculi (char. 59.1). The second group is mainly supported by the gular angle strongly obtuse (char. 33.2) and the antennal scape reaching to slightly exceeding hind margin of eyes (char. 35.1).
Each genus included in the tree was recovered as monophyletic with high nodal support (BP over 80%), except Asymmathetes, which is not monophyletic. On the contrary, the relationships among the Andean genera are weakly supported.
The new genus Obrieniolus is superficially similar to Amitrus, because both have a strongly sclerotized black integument, devoid of scales and are almost lacking setae, and have a distinct sculpture. However, the current cladistic analysis shows that the new genus is not closely related to Amitrus or to any other genus, justifying its treatment as a separate generic taxon. Characters such as the strongly sclerotized integu-ment, dull coloured, sculpturate, and usually devoid of scales, as well as the reduction of elytral humeri and metathoracic wings, are common in several groups inhabiting the high Andes, under similar extreme environments.
The Andean Naupactini are distributed in different biogeographic provinces of the Paramo-Puna subregion: Melanocyphus inhabit the Colombian Paramos; Obrieniolus occur in the Northern Puna, in the boundaries of the Peruvian Coastal Desert; Trichocyphus and Amitrus also inhabit in the Puna, but they reach a southern and broader distribution range; Amphideritus have representatives in the Paramos of Venezuela and Colombia, and along the Pacific coastal deserts of Peru and Chile; Asymmathetes inhabit the Paramos of Ecuador; and the species of Galapaganus inhabit in the Peruvian Coastal Desert, the Galapagos islands and continental Ecuador.