Two new species of Exetastes (Hymenoptera: Ichneumonidae: Banchinae) from the Peruvian Andes

Two new species of Exetastes Gravenhorst, 1829 from the Peruvian Andes are described and illustrated: E. andensis sp. nov. and E. tullu sp. nov. Presently, 38 species of Exetastes have been recorded in the Neotropical region. Our discoveries are the fi rst records of the genus in Peru and the Andean region.

Exetastes had not been recorded in Peru or any other Andean region prior to our discoveries. The aim of the present work is to describe and illustrate two new species of Peruvian Exetastes and to discuss their placement within the species groups proposed for the Neotropical region.

Morphological abbreviation
Diagnosis (updated from Gauld et al. 2002;Watanabe 2020) Moderate to large body size wasps. Metasoma usually slightly posteriorly compressed. Clypeus in lateral view from weakly convex basally, to almost pyramidal, without a subapical median swelling, in anterior view, not strongly transverse, margin usually fairly evenly sclerotized but thin, slightly concave. Mandibles weakly and evenly tapered apically, lower tooth equal in length, or slightly shorter or slightly longer than upper tooth; both teeth pointed or with the apex of the upper tooth broad and obliquely chisel-shaped (Townes 1970;Khalaim & Ruiz-Cancino 2012). Occipital carina dorsally complete, its lower part joining hypostomal carina a little above base of mandible. Antenna slender. Scape apically obliquely truncated. Mesosoma short, with the epicnemium sloping slightly backwards ventrally. Pronotum short, anteriorly with a transverse groove before broadly concave hind margin, its upper hind corner bluntly lobed, covering spiracular sclerite. Epomia absent or present as short trace-like ridge. Notauli absent. Mesopleuron with subalar prominence present as a low rounded to sharp promontory. Epicnemium without a distinct vertical tooth-like lamella near lower corner of pronotum. Posterior transverse carina of mesosternum entirely absent. Metanotum with hind rim simple or with a small tooth-like projection posteriorly. Metapleuron with submetapleural carina narrow, only slightly and evenly broadened anteriorly. Metasternum with weak ridges between coxal insertions. Propodeum short and quite steeply declivous. All propodeal carinae (except sometimes the pleural carina) absent. Propodeal spiracle subcircular to slightly oval. Legs slender with tibial spurs long. Hind leg very long and strong, with enlarged coxa. All tarsomeres cylindrical. Tarsal claws simple. Mid tibia without distinct denticles on outer surface. Fore wing with a large kiteshaped areolet. 2m-cu slightly sinuous, with single but long bulla. Usually cu-a opposite or slightly distal to base of Rs and M. Hind wing with distal abscissa of Cu1 joining cu-a close to M. Upper outer corner of subbasal cell almost right-angled, 95-100°. T1 with spiracle in anterior or central part. Glymma vestigial. Sclerotized part of first sternite not reaching spiracle. T2 slightly elongate (l.l-1.4 times as long as broad), with broad shallow thyridium anteriorly. Laterotergites of T2-3 indistinct, laterotergites of T4-5 not distinctly separated. Female hypopygium rather large and completely selerotized. Ovipositor short to moderately long (0.3-1.3 times as long as hind tibia), usually curved downward, compressed basally, its apex usually with a distinct dorsal subapical notch, without teeth on distal end of upper valve; rarely apically elongate tapered with a vestigial apical notch. Male with genital capsule short with a broad shallow notch ventrally.

Holotype
Mesosoma. Mesosoma entirely granulate, matt, mostly finely and densely punctate. Epomia and notaulus absent (Fig. 2B). Scutellum (Fig. 4B) pyramidal in profile. Subalar prominence strongly raised and sharply rounded. Metapleuron evenly convex, with submetapleural carina moderately raised, extending about 0.6 of length of pleuron. Propodeum (Fig. 2E) granulate, with reticulate sculpture; pleural carina absent anteriorly, strong posteriorly. Fore tibia slender, unspecialized. Hind femur 5.8 times as long as its maximum width in lateral view. Tarsal claw simple. Fore wing with 3rs-m meeting Rs without joining 2rs-m, enclosing an areolet that is narrowly truncate above, with abscissa of M between 2rs-m and 2m-cu as long as abscissa of M between 2m-cu and 3rs-m; cu-a more or less opposite base of Rs and M. Metasoma. T1 2.8 times as long as posteriorly wide; with spiracle positioned in anterior 0.46; granulate, matt, mostly finely and densely punctate (Fig. 2C). T2 0.9 times as long as posteriorly wide; granulate, matt, mostly finely and densely punctate. Ovipositor sheath elongate and slim, with transverse striation on outer surface. Ovipositor (Fig. 2F) projecting beyond apex of subgenital plate by 0.8 times length of hind tibia; stout, compressed, decurved, with subapical notch.

Variation
The paratype has the scuto-scutellar groove and anterior edge of T5-7 black.

Etymology
The specific epithet ʻtulluʼ means ʻthinʼ in Quechua, noun in apposition. Head. Clypeus, in profile, basally weakly convex, subapically slightly concave; 1.5 times as wide as high.
Mesosoma. Mesosoma entirely granulate, matt, mostly finely and densely punctate. Epomia absent. Notaulus faint (Fig. 3B). Scutellum, in profile, pyramidal (Fig. 4A). Subalar prominence strongly raised, sharply rounded. Upper half of metapleuron convex, lower half concave, upper margin scrobiculate, with submetapleural carina moderately raised extending about 0.7 of length of pleuron. Propodeum (Fig. 3D) granulate, matt, mostly finely and densely punctate; pleural carina present anteriorly, absent posterior to spiracle. Fore tibia slender, unspecialized. Hind femur 7.9 times as long as its maximum width in lateral view. Tarsal claw simple. Fore wing with 3rs-m meeting Rs without joining 2rs-m, enclosing an areolet that is narrowly truncate above; abscissa of M between 2rs-m and 2m-cu shorter than abscissa of M between 2m-cu and 3rs-m; cu-a distal to base of Rs and M.

Discussion
The species groups proposed by Gauld et al. (2002) are mainly distinguished by the shape of the scutellum and the length and shape of the ovipositor (see Table 1 for additional characters). The new Peruvian species do not fit within any of these species groups and are too heterogeneous to be placed in their own species group, suggesting the need for a reassessment of the features used to establish the species groups, ideally within a phylogenetic context.
The Peruvian Andes are one of the regions where Darwin wasps are least studied and may include numerous species of Exetastes that do not agree with the diagnostic features of the genus. For example, Exetastes andensis sp. nov. has the upper mandibular tooth broad and weakly subdivided (Fig. 2D), a feature which is also present in the Banchus genus group. However, genera of this group have large metasomal laterotergites which meet ventrally (Broad 2010), whereas Exetastes has laterotergites of T2 and T3 narrow, less than 0.3 times as broad as long (Townes 1970). The mandibles of Exetastes have a variety of shapes and proportions: lower tooth equal in length to upper tooth; lower tooth slightly shorter or longer than upper tooth; both teeth pointed; or with the apex of the upper tooth broad and obliquely chisel-shaped (Townes 1970;Khalaim & Ruiz-Cancino 2012). It is assumed the shape found in E. andensis sp. nov. is just part of this variability.
Exetastes tullu sp. nov. has mandibles with their upper and lower teeth equal in length, and without subdivisions, as in many species of Exetastes. This species has a highly distinctive elongate body but with a relatively short ovipositor (Fig. 3A). The length of the ovipositor of both new species does not fit with any of the species groups as defined by Gauld et al. (2002), being somehow intermediate between species of the ʻamancoiʼ group and species belonging to the other groups (Table 1). This is the second time that members of the genus are reported from South America, after two Brazilian species previously known from subtropical coastal Guaratuba, Paraná (Brullé 1846). For the Central American fauna it was mentioned that many species are restricted to higher altitude sites, around 1500-2000 m a.s.l. (Gauld at al. 2002;Veijalainen et al. 2014). This is probably also the case for species of Exetastes in the Andes. The Neotropical fauna of Banchinae is expected to be one of the most speciose ones (Klopfstein et al. 2019). The present work provides a significant improvement to the knowledge of biodiversity in the Andean region and to the morphological features characterizing the genus Exetastes, and it is hoped that more interest in the study of these Darwin wasps will arise from continued documentation of their diversity.