Psenulus pallipes ( Panzer , 1798 ) , an adventive wasp species ( Apoidea , Crabronidae ) newly recorded in the fauna of Chile

We document the presence of the Palearctic Psenulus pallipes (Panzer, 1798) in Chile for the first time. We believe this represents an adventive population introduced into the Neotropical region most likely by accidental human transportation of nests. A map of distribution in Chile, illustrations of external morphology, and a discussion of morphological features to distinguish the introduced taxon from the Neotropical species are presented.


Introduction
With about 170 described species, the wasp genus Psenulus is the largest in the Pemphredoninae (Apoidea, Crabronidae), presenting the greatest diversity in the Oriental, Ethiopic, and Palearctic regions (Bohart andMenke 1976, Pulawski 2018, Rosa andMelo unpubl. data).Psenulus has an unusual world distribution by having less diversity in the Neotropical region than other groups of Pemphredoninae (and several other groups of crabronids).Recently, 9 new species have been recognized, totaling 12 species in this region (Rosa and Melo unpubl.data).An exploratory phylogenetic investigation carried out by Rosa and Melo (unpubl. data) showed that both the Neotropical and the Holarctic fauna form separate monophyletic groups.
In the present note, we report an adventive population of Psenulus pallipes (Panzer, 1798), which is also newly recorded in Chile.A map with this species' Chilean distribution, illustrations of the external morphology, and a discussion of the morphological features to distinguish P. pallipes from the Neotropical species are presented.

Methods
Materials of Psenulus pallipes from the following institutions were examined: American Museum of Natural History (New York, USA; AMNH) and the Bee Biology and Systematics Laboratory (Logan, Utah, USA; BLCU).We used the identification key of Schmid-Egger (2016) and compared the Chilean specimens with 1 female of P. pallipes and 1 male and 1 female of P. chevrieri (Tournier, 1889) from Germany.These Old World specimens have been kindly provided by C. Schmid-Egger and are currently deposited in the Coleção Entomológica Pe.Jesus Santiago Moure, Departamento de Zoologia, Universidade Federal do Paraná (DZUP).
The general morphological terminology follows Bohart and Menke (1976).The color images were obtained on a camera Leica DFC295 connected to a stereomicroscope Leica M125 and processed by Zerene Stacker software.The data from labels of examined specimens were transcribed (see Materials examined), and a backslash (\) was used to indicate a new line of text on the label, and the single quotation marks enclose different labels associated with a specimen.
This species belongs to the Holarctic group and is widely distributed in the Palearctic region.The Holarctic clade is supported by the following characters: lower orbital margin shorter than width of base of mandible; F2 wider than long; separation between metasomal petiole and rest of tergum I indistinct; sternum II with a depressed triangle-shaped area; posterior margin of sternum IV straight (Rosa and Melo unpubl.data).
Psenulus pallipes (Figs.1-4) is easily distinguished from all Neotropical species by the wide frontal carina (Fig. 1), whose dorsal surface is excavated and crossed by fine transverse striation, by its coarse punctation on the head and mesosoma, the carinate upper portion of the frons, vertex and gena, pilose base of the propodeum, strongly carinate base of the propodeum in females, possession of specialized silk spinnerets along posterior margin of sterna IV and V (Fig. 3), and the pygidial plate entirely delimited by carinae.The studied specimens of Psenulus pallipes were collected in 5 of the 15 regions of Chile (Fig. 5), belonging to 5 different provinces: Curico (VII Region), Malleco (XIX Region), Ñuble (VIII Region), Santiago (RM Region), and Valparaíso (V Region).These Chilean regions are within the Mediterranean and temperate zones of the country, between latitudes 32°S and 48°S (Nahuelhual et al. 2007, Muñuz et al. 2016).Psenulus pallipes occurs in areas of the Old World having similar temperate climates (Schmid-Egger 2016, Pulawski 2018).Its presence in Chile is considered here as representing an adventive population introduced into the Neotropical region most likely by accidental human transportation of nests.
support during a visit to the AMNH, and Kevin Williams for his help in obtaining additional specimens for this study.Financial support has been provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico (grant GARM 309641/2016-0; BBR 130397/2013-0).