An update of the genera Idiasta Foerster and Rhacalysia Cameron (Hymenoptera, Braconidae, Alysiinae) and the descriptions of new species from the Neotropical Region

Abstract Taxonomic combinations have been made involving the two genera Idiasta Foerster and Rhacalysia Cameron. Four new species are described from Brazil: Idiasta rupinasp. nov., Rhacalysia amplasp. nov., Rhacalysia jataisp. nov., and Rhacalysia monteiroisp. nov. Dichotomous identification keys to the Neotropical species of Idiasta and Rhacalysia are provided. Phaenocarpa delicata Papp, 1969 is included in Rhacalysia and is a new combination.


Introduction
Idiasta Foerster, 1863 and Rhacalysia Cameron, 1910 are both genera of the tribe Alysiini (Braconidae, Alysiinae). Members of Idiasta possess the largest set of plesiomorphic characteristics within the Phaenocarpa complex (Wharton 2002). The taxon this park is classified as dense ombrophilous forest, and the physiognomies vary according to altitude: low-montane forests occur up to 600-800 m; montane forests are between 600-1600 m; high-montane forests may occur above 1300 m; and altitude fields occur above 1600 m (Rizzini 1979). Rhacalysia jatai sp. nov. was collected in Estação Ecológica de Jataí, Luiz Antônio, São Paulo, in a seasonal forest (Coutinho 1978). Wharton et al. (2017) was used to identify specimens in subfamily and genus. The morphological terminology is based on van Achterberg (1993); terminology for body sculpture follow Eady (1968). The measurements follow Wharton (1977), with additions and modifications by Zolnerowich (2005, 2008), except for legs, which are as in Peris-Felipo (2016). All the material is deposited in the DCBU collection (Departamento de Ecologia e Biologia Evolutiva da Universidade Federal de São Carlos, SP, Brazil).
Digital Scanning Electronic Microscope (SEM) photographs of uncoated specimens were taken with a FEI Quanta 250 SEM in a low vacuum mode. Color digital photographs were taken with a Leica M165C stereomicroscope, using a Leica DFC295 HD camera, LEICA APPLICATION SUITE software version 3.7. ADOBE PHO-TOSHOP CS5 Extended version 12.1. was used for minor corrections of images and for the preparation of plates.

taxonomic accounts
Genus Idiasta Foerster, 1863 Type species. Idiasta (Alysia) maritima Haliday, 1838 Diagnosis. Mandibles with three teeth, ventral and diagonal ridges well developed. First flagellar segment equal or shorter than second. Fore wing pterostigma broad, discrete, wedge-shaped; 2-SR vein longer than 3-SR. Hind wing with m-cu present, often well developed, M+CU generally equal to or longer than 1-M.
Head. 1.6× as wide as long; 1.8× as wide as face, 1.6× as wide as mesosoma, 3.3× as wide as apex of first metasomal tergite; slightly wider at eyes than temples in dorsal view. Eye glabrous, 1.2× as high as wide, 2.6× as wide as temple in lateral view (Fig. 2). Occiput, vertex, frons and temples smooth, with some sparse setae. Face 1.7 × as wide as high, setose; slightly rugulose above clypeus (Figs 3, 4). Epistomal sulcus well defined but almost shallow, slightly rugulose. Clypeus protruding, smooth, setose, 1.5× as wide as high; lateral margin of clypeus in contact with paraclypeal fovea (Fig. 3). Malar space ca. 1/10 eye height. Paraclypeal fovea occupying 2/7 of distance between lateral margin of clypeus to eye. Mandible 3-dentate (Fig. 4), 1.9× as long as apical width, slightly wider in apex than base; setose, rugulose antero-medially, punctate; diagonal ridge well developed on apical half of mandible, ventral ridge complete; teeth 1 and 2 connected by flange, incision present but unobtrusive; teeth 1 and 3 approximately equal in size, tooth 2 wider and longer than others. Antenna 1.8× as long as body, with 32 flagellar segments. First flagellar segment 3.3× as long as wide; second flagellar segment 8.2× as long as wide, 2.5× length of first segment; third flagellar segment 6.5× as long as wide, 1.8× length of first. Maxillary palp 1.7× as long as head height.
Mesosoma. 1.4× as long as high, 1.9× as long as wide, 1.7× as high as head. Pronotum in dorsal view with small but distinct pronope, crenulate in posterior margin; in lateral view, crenulate in upper middle area. Mesoscutum 1.1× as wide as long, scattered setae present along notauli. Notauli deep, crenulate anteriorly, absent posteriorly. Mesoscutal pit deep, slightly elongate, occupying a little less than 1/5 extent of mesoscutum. Scutellar sulcus 2.5× as wider as long, with well-developed mid ridge and some weak ridges at posterior margin of lateral areas. Scutellar disc smooth, setiferous; parascutellar area weakly rugulose posteriorly, with setae near scutellar sulcus. Metanotum setiferous anteriorly, in dorsal view rugose medially, depressed lateral fields crenulate; mid ridge complete and two well-developed median lateral ridges; metanotum in lateral view with high median flange. Mesopleuron with scattered setae in ventral area, antero-basal margin crenulate towards anterior subalar area; posterior margin crenulate. Precoxal sulcus deep, long, widely crenulate, separated from posterior margin (Fig. 5). Propodeum with anterior half nearly smooth and median carina; posterior half rugose, including inside areola; areola pentagonal, ca. as long as wide. Metapleuron rugose (except medially) and setose.
Fore wing. Approximately as long as body. Pterostigma 3.4× as long as wide, 2.25× as wide as vein r length; r 0.3× as long as 2-SR, arising distad midpoint of pterostigma; submarginal cell 2.6× as long as high; 2-SR 2.5× as long as r-m, 1.4× as long as 3-SR; 3-SR 2.65× as long as r, 1.8× as long as r-m; SR1 5.15× as long as 3-SR; 2-CU1 1.1× as long as m-cu, this interstitial; cu-a postfurcal by distance less than its length; subdiscal cell closed, nearly parallel-sided; CU1a arising slightly above middle of subdiscal cell (Fig. 6).
Hind wing. With three hamuli, 5.7× as long as wide; vein 1-M 1.15× as long as M+CU, 2.0× as long as 1r-m; m-cu interstitial, spectral (Fig. 7). Legs. Hind femur 6.35× as long as wide. Hind tibia 11.2× as long as its maximum subapical width, 0.9× as long as hind tarsus. First segment of hind tarsus 1.7× as long as second segment.

Metasoma.
First metasomal tergite 1.6× as long as apical width; apex 1.5× as wide as base; strongly strigose surface, dorsal carinae convergent and uniting in basal third, continuing as a distinct median carina to apex, dorsope deep. Ovipositor 1.3× as long as hind tibia, 1.45× as long as mesosoma; straight and strongly directed upwards (Fig. 1). Ovipositor sheath setose.
Male. Similar to female but body length 2.4 mm; hind wing 2.0 mm; head 3.0× as wide as apex of first metasomal tergite; antenna with 36 flagellar segments; first flagellar segment 3.9× as long as wide; second flagellar segment 7.95× as long as wide, 1.8 × length of first segment; third flagellar segment 7.0× as long as wide, 1.4× length of first segment; maxillary palp 2.4× as long as head height. Mesoscutum slightly longer than wide; scutellar sulcus 2.25× as wide as long. Fore wing with 2-SR vein 1.9× as long as r-m, 1.6× as long as 3-SR; 3-SR 1.2× as long as r-m. Hind wing 1-M 0.8× as long as M+CU, 2.6× as long as 1r-m. Hind femur 5.15× as long as wide; first segment of hind tarsus 1.5× as long as second segment. Antenna brown except yellowish basal half of first flagellar segment; wing venation and pterostigma light brown.
Etymology. The species name refers to the ecosystem from which the studied material was collected.
Comments. Idiasta rupina and I. dixi are related Neotropical species and share the notauli absent posteriorly, fore wing cu-a postfurcal, and hind wing m-cu not tubular. The color pattern of the body is also similar. However, Idiasta rupina can be differentiated by the glabrous eye (with sparse setae in I. dixi), high median flange of the metanotum (absent in I. dixi), fore wing m-cu interstitial (slightly antefurcal in I. dixi). Additionally, Idiasta rupina differ in the following quantitative ratios: eye 2.5 × as wide as temple (3.1× in I. dixi); maxillary palp ca. twice as long as head height (1.4 × in I. dixi); sulcus scutellar 2.5× as wide as long (1.4× in I. dixi); fore wing vein 3-SR 2.6 × as long as r (3.5× in I. dixi); SR1 5.1× as long as 3-SR (4.5× in I. dixi); ovipositor 1.4× as long as mesosoma (ca. 1.0× in I. dixi).
Hosts. Unknown. Distribution. Afrotropical, Asian, and Neotropical Regions. Diagnosis. Rhacalysia ampla can be differentiated from other species of genus by the notauli incomplete, precoxal sulcus sculptured only in anterior fourth, fore wing with m-cu interstitial, CU1a arising below middle of subdiscal cell, and hind wing with three hamuli.
Color. Mostly dark brown. Mandibles light brown to yellow, darker at base. Clypeus, scape, pedicel, scutellum, and metanotum brown to light brown. Flagellar segment 17-20 whitish (holotype). Mesonotum brown to reddish brown. Propodeum and metapleuron yellowish to dark orange. First metasomal tergite orange to yellowish orange, base of terga 2 sometimes orange, other tergites brown. Tegula, ovipositor, and most of legs yellow. Trochanter and tronchantellus pale yellow, telotarsus darkened; hind leg with distal tibia and tarsus brown. Wings hyaline; venation and pterostigma light brown to brown.
Male. Unknown. Etymology. The species name refers to the form of the paraclypeal fovea. Distribution. Brazil, State of Rio de Janeiro, Teresópolis, dense ombrophilous forest. Comments. Rhacalysia ampla is similar morphologically to R. delicata, with which it shares many characteristics. Members Rhacalysia ampla can be differing by the precoxal sulcus weakly sculptured only in the anterior fourth of mesopleuron ( Fig. 13) (sculpture shallow but long in R. delicata), vein CU1a of fore wing arising below middle of subdiscal cell (Fig. 15) (at middle in R. delicata), and the following quantitative ratios: eye ca. 3.0× as wide as temples (2.2× in R. delicata); mesosoma 2.0-2.4× as high as head (1.7× in R. delicata); pterostigma 1.9-2.2× as wide as vein r length (3.0× in R. delicata); hind femur 5.7-6.1× as long as wide (5.0× in R. delicata); and ovipositor 1.0-1.2× as long as hind tibia (2.0× in R. delicata).  Diagnosis. Rhacalysia jatai can be recognizable by the notauli and precoxal sulcus entirely smooth, fore wing with m-cu interstitial, CU1a arising at middle of subdiscal cell, hind wing with four hamuli; ovipositor 2.2× as long as mesosoma, body yellow (without brown parts).
Head. 1.7× as wide as long; 1.7× as wide as face, 1.6× as wide as mesosoma; 1.9 × as wide as apex of first metasomal tergite; slightly wider at eyes than temples in dorsal view. Eye glabrous, ca. as high as wide, 2.5× as wide as temple in lateral view (Fig. 22). Occiput, vertex, and temples smooth, with some sparse setae. Frons with weak pit mesally. Face 2.3× as wide as high, setose; low mid ridge dorsally and some weak transversal striae just above epistomal sulcus (Fig. 21). Epistomal sulcus deep, crenulate. Clypeus protruding, smooth, setose (setae as long as clypeus width), 1.6× as wide as high; lateral margin of clypeus does not contact with paraclypeal fovea. Malar space ca. 1/12 eye height. Paraclypeal fovea enlarged to form broad groove reaching to eye (Fig. 21).
Mandible 3-dentate (Fig. 19), 1.6× as long as apical width, apex 1.5× as wide as base; setose, slightly rugulose medially; diagonal ridge well developed on apical half of mandible, ventral carina present on basal third of mandible; teeth 1 and 2 connected by flange, indistinct incision; tooth 3 rounded, slightly wider than tooth 1; tooth 2 wider and longer than others. Antenna with apical flagellar segments missing, 31 flagellar segments present. First flagellar segment 3.5× as long as wide; second flagellar segment 5.6× as long as wide, 1.6× length of first segment; third flagellar segment 4.9× as long as wide, 1.4× length of first segment. Maxillary palp ca. twice as long as head height.
Legs. Hind femur 5.2× as long as wide. Hind tibia 11.2× as long as its maximum subapical width, 1.1× as long as hind tarsus. First segment of hind tarsus 1.95× as long as second segment.
Color. Body parts vary between dark brown to yellow . Head mostly yellow, vertex yellow to brown, ocellar field and epicranial suture dark brown; mandible light yellow. Flagellar segments brown to dark brown, except 18-19 whitish (holotype). Propleuron yellow; mesonotum yellow-orange, with more or less developed lateral and antero-medial spots brown, other parts of mesosoma varying from yelloworange to dark brown. Legs yellowish to orange; telotarsus brown; hind leg with tibia and tarsus darker. Metasoma yellow except for metasomal tergites 4 towards to apex and ovipositor sheaths brown. Wings hyaline to dusky, venation and pterostigma light brown to dark brown.
Male. Unknown. Etymology. The species is named in honor of Ricardo Ferreira Monteiro, the collector of the studied material.
Comments. Rhacalysia monteiroi shares many morphological characteristics with R. jatai; both species can be differentiated by the coloration pattern of body, relative length of the ovipositor, and relative length/wide of the posterior femur (see above).
The three specimens of R. monteiroi studied here vary considerably in some characteristics. In short, the sculpturing of face (striate or rugulose above the clypeus), notauli (smooth or weakly crenulate), precoxal sulcus (smooth or crenulate), and first metasomal tergite (with or without median carina); the coloration of vertex, pronotum, metanotum, propodeum, and metapleuron yellowish or brown . Despite this, the observed variations were not significant to consider them as different species.
Members of the genera Idiasta and Rhacalysia can be morphologically differentiated as follows: paraclypeal fovea not extending to eye in Idiasta (Fig. 3); paraclypeal fovea enlarged to form broad groove extending to eye in Rhacalysia (Figs 10, 21).

Discussion
The wing venation pattern of Idiasta is widely maintained in Rhacalysia. The morphological support for the retention of the generic status of Rhacalysia has been the enlarged paraclypeal fovea (Fischer 1967(Fischer , 1994Wharton 1980Wharton , 2002. However, although it is decidedly an apomorphic character within Alysiinae, it is not clear that all species with the enlarged paraclypeal fovea form a monophyletic group (Wharton 2002). The insertion antefurcal of vein m-cu of fore wing (and therefore 2-SR+M present) was considered diagnostic characteristic of Idiasta by Wharton (2002), supposedly differing from the trend observed in Rhacalysia species (this vein less antefurcal). Indeed, m-cu of fore wing is interstitial in most known Rhacalysia species but is antefurcal in R. congoensis and R. profundinigra. Moreover, this vein is interstitial in I. rupina (Fig. 6) and postfurcal in Apiasta Wharton, 2002, a subgenus of Idiasta known from Australian Region and considerably similar to Rhacalysia in morphology (Wharton 2002). It has also been argued that the density of setae on the ovipositor sheath is typically higher in Idiasta than Rhacalysia (Wharton 1980(Wharton , 2002. Here, we observed that the setae ovipositor sheath in R. ampla, R. jatai, and R. monteiroi are separated by a distance shorter than its length (Fig. 18), although sparser than I. rupina. Thus, this feature must be used carefully.
In addition to the enlarged paraclypeal fovea, all known species of Rhacalysia shares the follow characteristics: fore wing with pterostigma distinct and wide, vein r arising from its distal middle, vein r shorter than pterostigma width, cu1 postfurcal (Figs 15, 25, 32); mid ridge present on face (at least weakly developed); and first metasomal tergite widened towards to apex (apical width ca. twice the basal) (Fig. 17). Furthermore, the vein CU1a of fore wing not interstitial, m-cu of hind wing welldeveloped, and indistinct incision between mandibular teeth 1 and 2 (Figs 11,19,29), are characteristics shared by all species except R. congoensis, with relatively distinct morphology, in which the CU1a of fore wing is interstitial, m-cu of hind wing absent, and there is well defined incision between teeth 1 and 2.
Studies covering more Rhacalysia specimens in the future, should provide a clearer and more conclusive morphological delineation in relation to the genus Idiasta, especially if together the analysis of molecular data. Nevertheless, as well as Fischer (1994) and Wharton (2002), we maintain the genus position of Rhacalysia, and consider R. delicata part of it, based on the new species described here.
Considering our records, the distribution of Idiasta is slightly altered: the genus is no longer recorded from Argentina, Peru, and Venezuela. In turn, considering delicata species as Rhacalysia, the genus Rhacalysia is now known from many countries of the Neotropical Region.