A new species of Lathrolestes Förster (Hymenoptera: Ichneumonidae) from Peruvian Amazonia

Abstract Lathrolestes fiedleri sp. n. is described from Peru. This is the first record of the tribe and the genus for the country.

The purpose of this paper is to describe a new species of Lathrolestes from the Peruvian Amazonia. Lathrolestes belongs to Perilissini, one of the nine tribes of the subfamily Ctenopelmatinae. The genus includes 102 species Horstmann 1997 (Yu et al. 2012 is not cited here since L. pleuralis (Thomson, 1883) was placed as synonym of L. caudatus (Thomson, 1883) by mistake in the newest version of the catalogue), Reshchikov 2013a, Reshchikov 2013b]. Nine species are known from the Northern part of Neotropical region: four species from Costa Rica (Gauld et al. 1997), four from Mexico (Reshchikov 2011) and one from Ecuador . The new species, Lathrolestes fiedleri sp.n., was collected in the Ucayali Region of Peruvian Amazonia. This represents the first genus-level record of the subfamily Ctenopelmatinae from Peru (Veijalainen et al. 2013) and the second record of the genus Lathrolestes in South America (Reshchikov et al. 2012). An illustrated diagnosis with comparisons with other Neotropical species is provided.

Materials and methods
Lathrolestes is a rarely collected genus of Ctenopelmatinae, and it is generally poorly represented in collections. This study is based on 1 specimen which was found in the MUSM. The morphological terminology used in this study follows that of Gauld et al. (Gauld et al. 1997). Photographs were taken with a Canon Digital Camera 5D, combined with Zerene ®.

Diagnosis
Small to medium sized species, 4.0-7.5 mm. Occipital carina not intercepting hypostomal carina. Clypeus profile almost always flat, its apical margin thick. Head behind eyes usually narrowed. Mandibles with lower tooth distinctly longer than the upper. Pronotum with epomia absent or vestigial, never discernible as a long crescentic ridge. Epicnemial carina never reaching the fore margin of mesopleuron. Notch between postscutellum and propodeum V-shaped. Radius intercepting pterostigma at its middle or before its middle but never at its base. Areolet petiolate, oblique, sometimes absent. 2m-cu with a single bulla. Hind wing with cu-a intercepted below or at its middle. Tarsi not swollen. Tarsal claws pectinate, with basal lobe, or not pectinate. Glymmae deep. Epipleura of second and third metasomal tregites separate from tergites. Apex of subgenital plate of male not incurved on hind margin. Tip of aedeagus somewhat decurved and swollen, its apex rounded. Ovipositor sheath 0.3 to 15 as long as metasomal height. Ovipositor usully stout at base, with notch or nodus at appex but never nidle-like.

Description
Body length 7 mm. Antenna with 20 flagellomeres. Scape 1.3 times as long as wide. Head narrowed behind compound eyes (Fig. 1a), matt, not punctate, shagrined. Maximum length of gena 0.63X transverse eye diameter; minimum length of gena 0.4X transverse eye diameter. Width of face equal to height of eye (Fig. 1b). In lateral profile face slightly convex, with bulge, lateral parts at inner eye margin with slight impression. Interspace between hind half of lateral ocellus and eye and vertex matt or dimly shining, 1.6X transverse ocellus diameter (Fig. 1a). Clypeus rather long, 0.5 times as long as medially wide, separated from face by deep impression (Fig. 1b) Fore wing with cu-a strongly postfurcal. Propodeal carinae complete, strongly raised; area superomedia half as long as wide, anterior part (before costula) of area apicalis slightly longer than posterior part (Fig. 1c).

Diagnosis
This species differs from other species of the genus by the combination of the following character states: elongate clypeus, 0.5 times as long as medially wide, separated from face by deep groove (Fig. 1b) (in other members of the genus clypeus shorter, 0.2-0.4 times as long as medially wide, except L. gauldi Reshchikov et al, 2012 and L. protenus Barron, 1994, species with also elongated clypeus, separated from face by deep groove, but L. protenus Barron, 1994 has outstanding unique character state, occipital carina intercepting hypostomal carina before base of mandible (Barron 1994)); short first metasomal tergite, as long as apically wide (in other members of the genus 1.2 -1.8 times as long as apically wide, excluding L. zeugophorae Barron, 1994 and L. gauldi, but L. zeugophorae characterized by shorter clypeus and lack of costula) without longitudinal dorsal carinae (Fig. 1d); short area superomedia, 0.5 times as long as broad (Fig. 1c); infuscate wings ( Fig. 2) with resemblance of areolet; and claws elongate, not pectinate. This species is morphologically closely related to L. gauldi and can be grouped together by the combination of the character states mentioned above. Synapomorphies shared with L. gauldi are short area superomedia (0.5 times as long as broad), infuscate wings, vestigial areolet, and elongate, not pectinate claws. The new species clearly differs from the Ecuadorean species in coloration (reddish face, gena, hind coxa and femur, and metasomal tergites except the last three tergites; Figs 1, 2), and by the lack of longitudinal dorsal carinae of first metasomal tergite. Lathrolestes gauldi has a black face, gena, completely black hind legs and metasoma, and defined longitudinal dorsal carinae of the first metasomal tergite (see ).

Etymology
This species is named after Arkady Fiedler.

Distribution
Peru.

Conservation
This species seems to be a rare species, and further sampling is needed to clarify its distribution in the Western Amazonia.

Discussion
In the summer of 2014, while participating in the 8th International Congress of Hymenopterists in Cusco, I had the opportunity to go through the collections of Cusco University and Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos (MUSM). I also did some collecting in South Eastern Peru in August 2014. Previously I had checked the Neotropical Ichneumonidae collections of several other institutions (ANSP, AMNH, NHRS, USNM, ZMUT). Despite all my efforts and the large sampling effort taking place in many Amazonian study localities (Veijalainen et al. 2013) I encountered the first and so far only L. fiedleri sp. n. specimen in the MUSM collection. Similar to the previousely described Amazonian species, L. gauldi Reshchikov et al 2012, L. fiedleri sp. n. seems to be a rare species, and further sampling is needed to clarify its distribution in the Western Amazonia. I consider the description of this species as rather important for drawing attention to the loss of biodiversity in the region due to mining and logging (Gardner 2012, Goncalves et al. 2012, Risen 2011, Swenson 2011.