Revision of the Australasian genus Pseudidarnes Girault, 1927 (Hymenoptera, Agaonidae, Sycophaginae)

Abstract The species of Pseudidarnes are revised, and six species are described: P. acaudus Farache & Rasplus, sp. n.; P. astridae Farache & Rasplus, sp. n.; P. badiogeminus Farache & Rasplus, sp. n.; P. cooki Farache & Rasplus, sp. n.; P. kjellbergi Farache & Rasplus, sp. n.; P. laevis Farache & Rasplus, sp. n. Pseudidarnes minerva Girault, 1927 and P. flavicollis Bouček, 1988 are redescribed. A key to the species is provided as well as illustrations for all females and all known males (except the wingless male of P. minerva). We also provided further discussion on ecology, morphological patterns, and host taxonomy. Online dichotomous and multi-access interactive LUCID keys to all Pseudidarnes species are available at http://www.figweb.org/.


Introduction
Sycophaginae is one of the six subfamilies of chalcid wasps that are strictly associated with Ficus syconia. A recent phylogenetic analysis of the Chalcidoidea recovered Agaoninae (fig pollinators) + Sycophaginae as a monophyletic group (Agaonidae), syconium wall during the early development of the syconia before pollination (Cruaud et al. 2011b, Elias et al. 2008. Induction of large galls is usually correlated with small brood sizes, and their galls may occupy the whole syconium lumen (Bronstein 1999;Cook et al. 1997, West andHerre 1998). As other large gall inducers, Pseudidarnes species are usually rare in most host species and found in low abundance (0.1 ± 0.5, mean ± SE, insects per fig in F. obliqua) (Segar and Cook 2012).
Pseudidarnes males are usually winged, but wingless males of P. minerva were recorded with very low frequencies (Cook et al. 1997, Early 2000. The small wingless males mate with females inside the figs even before females leave their galls, while winged males usually (but not always) disperse before mating (Cook et al. 1997).
In this paper we describe and illustrate six previously unknown species (two from Australia and four from Papua New Guinea). Redescriptions are also provided for P. minerva and P. flavicollis. We finally elaborated both dichotomous and interactive online keys to the known species of Pseudidarnes.

Specimen sampling and morphological study
Maturing fig syconia were collected, opened, and transferred to tissue bags until the wasps emerge, which happens after a few hours -days. Wasps were killed using acetate and transferred to 70% ethanol. Most geographical coordinates and altitudes were estimated using label information. Field recorded coordinates were provided when available. Field-collected specimens were dehydrated through an ethanol and HMDS series (Heraty and Hawks 1998) and then mounted on cards following Noyes (1982). Morphological terminology follows Gibson (1997). Material examined sections of species descriptions were prepared using AUTOMATEX (Brown 2013), and posteriorly refined.
Type and specimen depositories, and their respective curators are:

Illustration
To produce high quality images, some specimens were point-mounted on grey card in order to avoid loss of contrast caused by white background. Images were produced with an EntoVision Premium Portable Imaging System, comprising a Leica M16 zoom lens, a JVC KY-75U 3CCD digital camera and a portable computer workstation running EntoVision Imaging Suite software (GT Vision, Hagerstown, MD U.S.A.). Cartograph v5.6.0 (Microvision, Evry, France) software was subsequently used to merge an image series (representing about ten to twenty focal planes), producing a single image with increased depth of field. Illumination was achieved using a "quadrant" setup, with four fibre optic light guides stemming from two individual light sources (Leica CLS 150 X), similar to the one described by Buffington and Gates (2008). Images were edited using Adobe Photoshop CS4© software.
Head. Face sculpture smooth to reticulate or slightly engraved, sometimes punctate. Antennae inserted well above to slightly below the middle line of compound eyes, but never very close to the clypeal margin. Toruli separated by one torulus diameter or less. Clypeal margin bilobed. Maxillary palpi composed of four segments. Labial palpi composed of three segments. Supraclypeal area delimited by subantennal grooves. Antenna with 13 segments (two anelli), and a 14 th segment very short and unconspicuous. Funicular segments 1-2 × as long as wide.
Mesosoma. Pronotum 1-2 × as long as high in lateral view. Notauli complete, deep and at least slightly crenulated. Mesoscutum as long as wide or longer than wide. Axilullar sulcus straight to slightly concave. Propodeum transverse, smooth to slightly reticulate and sometimes with a median sulcus. Wings hyaline, sometimes slightly infuscate medially. Marginal vein as long as stigmal vein, or longer. Postmarginal vein present (very short in P. cooki sp. n.). Marginal and postmarginal vein sometimes particularly widened (as Figs 4D, 6D, 8D, 10D & 16D).
Male. Very similar to female, usually slender and sometimes showing tinge variation. Male with very different colour patterns in P. astridae sp. n. (Figs 3-6).

Key to species of Pseudidarnes Girault (based mainly on females)
Online dichotomous and multi-access interactive LUCID keys to Pseudidarnes species are available at: http://www.figweb.org/Fig_wasps/Agaonidae/Keys/index.htm 1 Ovipositor sheaths extremely short, only weakly protruding beyond metasoma apex ( Figure 1A). Pedicel elongated, slightly shorter than the scape (Fig.  1D). Mesosoma entirely brown ( Fig. 2A)  Ovipositor sheaths short, about as long as the metasoma (Fig. 11A Petiole transverse in dorsal view (Fig. 18D). Median sulcus of the propodeum broad and extending over the anterior half of the sclerite (Fig. 18B). Postmarginal vein shorter than the stigmal (Fig. 18F)  Head. Antennae inserted far above the middle line of compound eyes. Scape slightly longer than pedicel. Pedicel very elongated (more than 2 × as long as wide), slender, and longer than first funicular segment. Anelli almost as long as wide, proximal anellus longer than wide. First funicular segment approximately 1.5 × as long as wide. Distal antennomeres not forming a distinct clava. Face sculpture slightly engraved. Face pilosity short and sparse. Supraclypeal area narrow, its delimiting sulci converging near epistomal groove, and its sculpture barely rugose. Lateral ocelli nearly 1 × its diameter far from the eye margin.
Mesosoma. Pronotum longer than high in lateral view. Mesoscutum slightly engraved reticulate. Frenal sulcus smooth. Mesepimeron sculpture mostly smooth, slightly engraved. Metascutellum very short and smooth, inconspicuous, and almost completely covered by frenum. Propodeum with a well delimited and slightly carinulated median sulcus, which extends to the posterior margin of the sclerite. Propodeum sculpture smooth, slightly rugose. Wings hyaline, with sparse pilosity. Marginal and postmarginal vein not particularly widened. Postmarginal vein as long as stigmal vein.
Metasoma. Petiole smooth and transverse in lateral view. Petiole dorsally without a longitudinal median sulcus. Ovipositor sheaths extremely short, only weakly protruding beyond metasomal apex.
Male. Unknown Etymology. The specific name refers to the short ovipositor sheaths exhibited by this species.
Biology. Associated with an undetermined Ficus species collected in Papua New Guinea. Reared together with Pseudidarnes laevis sp. n., but less abundant than the later.  Paratype. ♂ Same data as holotype (CBGP). Diagnosis. Body without metallic tinge. Pronotum long, nearly 1.5-2 × as long as high in lateral view. Mesoscutum with faint irregular transverse striae. Median area of metascutellum and median area of propodeum with irregular transverse rugae. Marginal and postmarginal vein widened.
Head. Antennae inserted far above the middle line of compound eyes. Scape more than 2 × as long as pedicel. Pedicel elongated, slender, but shorter than first funicular segment. Anelli almost as long as wide. First funicular segment 2 × as long as wide. Distal antennomeres not forming a distinct clava. Face sculpture smooth with sparse punctures, lower face slightly engraved. Face pilosity long and dense. Supraclypeal area wide, its delimiting sulci not converging near epistomal groove, and its sculpture mostly smooth. Lateral ocelli 0.5 × its own diameter far from the eye margin.  Metasoma. Petiole rugose, 1.7 × as long as high in lateral view. Petiole dorsally without a longitudinal median sulcus. Ovipositor sheaths long, distinctly protruding beyond metasoma apex. Ovipositor sheaths length 2.8 × hind tibia length and 0.5 × body length.
Male. Body length 4.2 mm. Characters agreeing with females, except the following. Body colour browner, mesoscutellum yellow in dorsal view. Posterior ocelli contiguous to the eye margin, and larger. Wing infuscation more pronounced. Etymology. The specific name is dedicated to our friend Astrid Cruaud for the long long walks we share together in the jungles of the world, trying to find fig trees.
Biology. Reared from syconia of Ficus xylosycia Diels. Ficus xylosycia hosted three Pseudidarnes species. Pseudidarnes badiogeminus sp. n. was collected together with P. astridae sp. n. in New Britain, whereas P. flavicollis Bouček was collected in Bulolo. We are convinced that the host identification is correct for both samplings and that the guilds of non-pollinating fig wasps may vary with geography.   Flagellomeres yellow brown. Head dark brown. Pronotum yellow brown laterally. Legs yellow, coxae browner.
Head. Antennae inserted far above the middle line of compound eyes. Scape nearly 2 × as long as pedicel. Pedicel elongated, slender, and as long as first funicular segment. Proximal anellus longer than wide. First funicular segment 2 × as long as wide. Distal antennomeres not forming a distinct clava. Face sculpture engraved, slightly rugose. Face pilosity short and sparse. Supraclypeal area narrow, its delimiting sulci converging near epistomal groove, and its sculpture barely rugose. Lateral ocelli 0.5 × its own diameter far from the eye margin.
Male. Body length 3.2 mm. Characters agreeing with females, except the following: ocelli larger and contiguous to the eye margin. Pedicel slightly shorter.
Etymology. The specific name refers to the similarity of P. badiogeminus with P. astridae, but showing different colour.
Biology. Collected from syconia of F. xylosycia. See P. astridae for further information. Head. Antennae inserted just above the middle line of compound eyes. Scape nearly 3 × as long as pedicel. Pedicel almost as long as wide, pyriform, and shorter than first funicular segment. Anelli transverse. First funicular segment approximately 1.5 × as long as wide. Distal antennomeres forming a distinctive clava. Face sculpture reticu-late. Face pilosity short and sparse, becoming longer near oral margin and eyes. Supraclypeal area wide, its delimiting sulci not converging near epistomal groove, and its sculpture mostly smooth. Lateral ocelli 1 × its own diameter far from the eye margin.

Pseudidarnes cooki
Mesosoma. Pronotum short, nearly as long as high in lateral view. Mesoscutum strongly reticulate. Mesoscutellum reticulate. Frenal sulcus densely crenulated. Mesepimeron sculpture reticulate. Metascutellum longer than frenum, reticulate. Propodeum with a well delimited and carinulated median sulcus, extending to the posterior margin of the sclerite. Propodeum sculpture reticulate, smooth near the Metasoma. Petiole rugose, 1.5 × as long as high in lateral view. Petiole dorsally with a longitudinal median sulcus. Ovipositor sheaths long, distinctly protruding beyond metasoma apex. Ovipositor sheaths length 2.25 × hind tibia length, 0.4 × body length. Male. Body length 2.4 mm. Characters agreeing with the females, except the following. Body slender. Antenna more yellow and inserted at the middle line of compound eyes or slightly below. Ocelli larger. Body sculpture fainter. Petiole more brown. Wings more pilose.
Etymology. The specific name is dedicated to our friend and colleague Dr. James Cook, in recognition of his amazing contribution to our knowledge of fig wasps. Biology. This species is strictly associated with Ficus obliqua G. Forst. and was studied by Segar and Cook (2012) (referred as Pseudidarnes sp.). It was reared in low abundance (0.1 ± 0.05, mean ± SE) and there were rarely more than four wasps in the same syconium.
Head. Antennae inserted far above the middle line of compound eyes. Scape nearly 2 × as long as pedicel. Pedicel elongated, slender, and shorter than first funicular segment. Anelli transverse. First funicular segment 2 × as long as wide. Distal antennomeres not forming a distinct clava. Face sculpture smooth with sparse punctures, lower face with engraved transverse striae. Face pilosity short and sparse, becoming longer near oral margin and eyes. Supraclypeal area wide, its delimiting sulci not converging near epistomal groove, and its sculpture mostly smooth. Lateral ocelli contiguous to the eye margin.
Mesosoma. Pronotum long, nearly 1.5-2 × as long as high in lateral view. Mesoscutum transversally striate. Mesoscutellum smooth. Frenal sulcus densely crenulated. Mesepimeron sculpture slightly striate. Metascutellum as well as lateral panel of metanotum crenulated, metascutellum longer than frenum. Propodeum with a well delimited and carinulated median sulcus, extending to the posterior margin of the sclerite. Propodeum sculpture mostly smooth, slightly rugose laterally. Wings hyaline, with rather dense pilosity. Marginal   Head. Antennae inserted at the middle line of compound eyes. Scape nearly 3 × as long as pedicel. Pedicel almost as long as wide, pyriform, and as long as first funicular segment. Anelli transverse. First funicular segment approximately as long as wide. Distal antennomeres forming a distinctive clava. Face sculpture reticulate. Face pilosity short and sparse. Supraclypeal area wide, its delimiting sulci not converging near epistomal groove, and its sculpture mostly smooth. Lateral ocelli nearly 1 × its diameter far from the eye margin.  Metasoma. Petiole slightly rugose, and transverse in lateral view. Petiole dorsally without a longitudinal median sulcus Ovipositor sheaths long, distinctly protruding beyond metasomal apex. Ovipositor sheaths length 3.8 × hind tibia length, 0.7 × body length.
Male. Unknown Etymology. The specific name is dedicated to our friend and colleague Dr. Diagnosis. Mesosoma metallic green, entirely smooth and shiny. First funicular segment 2 × as long as wide. Distal antennomeres not forming a definite clava.
Description. Female. Body length 3.7 mm. Ovipositor sheaths length 3.9 mm. Metallic tinge present at least in some body regions. Predominantly dark green. Antennae yellow brown. Legs yellow. Petiole dark brown. Metasoma predominantly brown, slightly green.
Head. Antennae inserted at the middle line of compound eyes or slightly above. Scape nearly 3 × as long as pedicel. Pedicel almost as long as wide, shorter than first funicular segment. Anelli transverse. First funicular segment 2 × as long as wide. Distal antennomeres not forming a distinct clava. Face sculpture smooth, with very sparse punctures. Face pilosity short and sparse. Supraclypeal area wide, its delimiting sulci not converging near epistomal groove, and its sculpture mostly smooth. Lateral ocelli nearly 1 × its diameter far from the eye margin.
Mesosoma. Pronotum longer than high in lateral view. Mesoscutum mostly smooth. Mesoscutellum smooth. Frenal sulcus densely crenulated. Mesepimeron sculpture mostly smooth. Metascutellum smooth, very short, inconspicuous, and almost completely covered by frenum. Propodeum with a vestigial median line not extending from the beginning of the proximal region. Propodeum sculpture smooth. Wings hyaline, with rather dense pilosity. Marginal and postmarginal vein not particularly widened. Postmarginal vein as long as stigmal vein, or slightly longer.
Metasoma. Petiole 2 × as long as high in lateral view. Petiole sculpture in lateral view slightly rugose. Petiole dorsally with a longitudinal median sulcus. Ovipositor sheaths long, distinctly protruding beyond metasoma apex. Ovipositor sheaths length 4.3 × hind tibia length, as long as body.
Male. Body length 3 mm. Characters agreeing with the females, except the following. Body slender. Anelli more transverse. Ocelli slightly larger than the female's ocelli. Wing more pilose.
Etymology. The specific name refers to the smooth body sculpturation exhibited by this species.
Diagnosis. Mesosoma metallic green, mostly reticulate. Median sulcus of the propodeum extending over most of the propodeum length, not reaching the posterior margin. Postmarginal vein as long as the stigmal. Petiole longer than wide in dorsal view. Ovipositor sheaths longer than metasoma.
Coloration. Metallic tinge present at least in some body regions. Predominantly green. Scape yellow. Petiole yellow brown. Flagellomeres brown. Coxae almost con- Head. Antennae inserted at or slightly below the middle line of compound eyes. Scape nearly 3 × as long as pedicel. Pedicel almost as long as wide, pyriform, and as long as first funicular segment. Anelli transverse. First funicular segment longer than wide to approximately as long as wide. Distal antennomeres forming a distinctive clava. Face sculpture reticulate. Face pilosity short and sparse. Supraclypeal area wide, its delimiting sulci not converging near epistomal groove, and its sculpture mostly smooth. Lateral ocelli nearly one diameter far from the eye margin. Mesosoma. Pronotum short, nearly as long as high in lateral view, or slightly longer than high. Mesoscutum reticulate. Mesoscutellum engraved. Frenal sulcus densely crenulated. Mesepimeron sculpture reticulate. Metascutellum very short, inconspicuous, and almost completely covered by frenum. Propodeum with a carinulated longitudinal median line, extending over most of the propodeum length, not reaching the posterior margin. Propodeum sculpture engraved reticulate, smooth near the proximal region of median line of propodeum. Petiole 1.5 × as long as high in lateral view. Metasoma. Petiole sculpture in lateral view slightly rugose. Petiole dorsally with a longitudinal median sulcus. Ovipositor sheaths long, distinctly protruding beyond metasoma apex. Ovipositor sheaths length 4.4 × hind tibia length, 0.9 × body length.
Male. Body length 2.3 mm. Characters agreeing with the females, except the following. body slender. Coxae brown, not concolorous with mesosoma. Anelli more transverse than  female. Head sculpture engraved. Ocelli ca. 2 × the diameter of the female's. Body sculpture fainter. Wing more pilose.
Wingless males were described for this species (Early 2000), but they are uncommon. Biology. Reared from Ficus rubiginosa Desf. ex Vent. syconia. Ficus rubiginosa is pollinated by Pleistodontes imperialis Saunders. Usually collected in low abundances, but sometimes they are quite abundant, at least in Eastern Australia and Auckland (as seen by Early 2000). Details about the biology of Pseudidarnes minerva and other wasps associated with F. rubiginosa in New Zealand were described by Early (2000).
Molecular data. GenBank sequences: COI HM770660; CytB HM770560; EF1a HM770504; rRNA 28S HM770665 (Cruaud et al. 2011a;Cruaud et al. 2011b Comments. Two specimens belonging to this species were included in the phylogenetic analysis by Cruaud et al. (2011a;2011b). The remaining specimen is a male in poor state of conservation as it was removed from its gall before emergence, and cannot be described.

Discussion
Due to their low abundance and relative rarity, some species were described here from very small series. Nevertheless, many specimens of P. laevis were collected from the same sample of figs, which indicates that they can sometimes show high infestation rates. This pattern is also observed in Anidarnes, which are also large gallers, and are usually found at low abundances (Bronstein 1999) but are more abundant in a few samples (personal observation, Farache et al. 2013). The relative low abundance (compared to fig pollinators and some other Sycophaginae that induce smaller galls) shown by Pseudidarnes and Anidarnes may explain the difficulty experienced by earlier taxonomists when studying and describing species belonging to these genera.
Here we collected and analysed wasps from both sexes in five from the eight studied species. Pseudidarnes males were similar to the females, in contrast to many other wasps associated with fig inflorescences, which are sexually dimorphic and show wingless males. Nevertheless, wingless males occur in very low abundance for P. minerva (Cook et al. 1997, Early 2000, so the fact that we did not find them in other Pseudidarnes species may be due to sampling effect, and therefore new dimorphic males may be found in the future. Also, wingless males do not leave their natal figs and remain within flowers and bracts, which may hamper their sampling by unaware collectors. The eight Pseudidarnes species were collected from five different hosts. F. xylosycia hosted three species, namely P. astridae, P. badiogeminus, and P. flavicollis. The former two species were reared together in the same sample. An undetermined fig species also hosted two species, P. laevis and P. acaudus (reared in a same sample). Despite the fact that more than one species may share the same fig, we did not find any Pseudidarnes species occurring in more than one host, which possibly indicates that they are host specific.
Pseudidarnes acaudus is the most divergent of all collected species, and is easily recognizable by its extremely short ovipositor sheaths. The other species can be separated into two morphological groups that correspond well to their geography and to their host association. Papuan species show a slender mesosoma, long funicular segments, and body sculpture that is mostly smooth, while Australian species have a short and robust mesosoma, shorter funicular segments, and a reticulate body sculpture. The taxonomy of the section Malvanthera is also geographically consistent since two of its subsections (namely Malvantherae and Platypodeae) are primarily Australian, while subsection Hesperidiiformes has its diversity centre in New Guinea (Rønsted et al. 2008). All Australian hosts collected belong to subsection Platypodeae, whereas F. xylosycia from Papua belongs to subsect. Hesperidiiformes. The host of P. laevis is unknown, but probably it belongs to subsect. Hesperidiiformes, since the only species belonging to other Malvanthera subsections known to occur in Papua is F. obliqua (Rønsted et al. 2008).
This is the first revisionary treatment of Pseudidarnes. We believe that, due to the lack of previous careful sampling, several Pseudidarnes species remain to be discovered especially in New Guinea, but also in Australia. We hope that this work will encourage discovery and further studies on the biology of Pseudidarnes species.