First record of the genus Oodera Westwood, 1874 (Hymenoptera, Pteromalidae, Cleonyminae, Ooderini) from the Arabian Peninsula, with the description of four new species

Abstract The genus Oodera Westwood, 1874 (Hymenoptera, Pteromalidae, Cleonyminae) is recorded for the first time for the Arabian Peninsula, from the Kingdom of Saudi Arabia and the Sultanate of Oman. The present study is based on specimens reared from xylophagous beetle larvae of the family Buprestidae (Coleoptera) infesting dead Acacia trees from Al-Dakhiliyah and Dhofar governorates in Oman and Al-Baha, Asir and Riyadh regions in Saudi Arabia. Four new species, Oodera arabicasp. nov., O. omanensissp. nov., O. rapuzziisp. nov., and O. similissp. nov. are described, illustrated and compared with closely related Oodera species. An illustrated key and the xylophagous host records of the species are also provided.


Introduction
Oodera Westwood, 1874 (Hymenoptera, Pteromalidae, Cleonyminae) is a relatively small genus comprising currently twenty valid species (Werner and Peters 2018). It includes different-sized species (3.6−17 mm) (Werner and Peters 2018). Based on Holt et al. (2013), they are distributed in the Oriental region (eight species), Afrotropical region (six species), Palaearctic region (six species) and Nearctic region (one species) (Noyes 2018;Werner and Peters 2018). However, the relatively recent report of O. formosa (Giraud) from the United States of America results from an accidental introduction from Europe (Werner and Peters 2018). Almost all Oodera species are reported as parasitoids of xylophagous beetle larvae of the families Buprestidae and Curculionidae (Coleoptera, Scolytinae) (Bouček 1958;Bouček and Rasplus 1991;Yang 1996;Gibson 2003;Werner and Peters 2018). Other details about their biology are still unknown (Werner and Peters 2018).
The phylogenetic status of Oodera has remained in dispute for a long time (Gibson 1989). It has been proposed as forming a link or a bridge between Cleonyminae (Pteromalidae) and Eupelminae (Eupelmidae) (Bouček 1958(Bouček , 1988Graham 1969) and has been classified and keyed in Eupelmidae rather than Cleonyminae by some authors (Ashmead 1904;Nikol'skaya 1952;Graham 1969). It was transferred from Eupelmidae to Pteromalidae by Bouček (1958) who established the monotypic tribe Ooderini for the genus in the subfamily Cleonyminae, family Pteromalidae (Heraty et al. 2013). The presence of a peculiar system of spines and spine-like setae along the ventral margin of the profemur, and the absence of a flexible transscutal articulation both support the monophyly of Oodera (Gibson 2003). On the other hand, the very distinctive structures and modifications of its middle legs (thickened mesotibial spur; presence of mesotarsal pegs; the presence of a membranous area anterior to each mesocoxa) might support the hypothesis of it being a sister of Eupelmidae or some part of it (Gibson 1989).
The first comprehensive work dealing with the taxonomy of the genus Oodera was that of Werner and Peters (2018), who revised the world species based on the morphological examination of 115 specimens. They reported twenty valid species for the genus, of which ten species were described as new to science. An illustrated key to all species, re-description of the other valid ones, with taxonomic treatments to some of them, were also given.
In the present study, Oodera is recorded for the first time for the fauna of the Arabian Peninsula, from Oman and Saudi Arabia. Specimens were reared from the dead wood of Acacia sp. trees. Four new species are described and illustrated. An illustrated key and the xylophagous hosts of species are also provided.
Photographic images were taken using a Canon EOS 70D camera attached to a Leica MZ 125 stereomicroscope. Individual source images were then stacked using HeliconFocus v6.22 (HeliconSoft Ltd) extended depth of field software. Further image processing was done using the software Adobe Photoshop CS5.1 (ver. 12.1x 32) and Adobe Photoshop Lightroom 5.2. Morphological measurements of the different parts were made with the help of a Zeiss Stemi 2000-C stereomicroscope with an ocular micrometer (100 lines per mm). Body part measurements were taken with the same magnification (20× eyepiece, 2.5× objective) for calculating different body ratios accurately and facilitate comparison. The detailed description for each species under study is based on the holotype specimen; for the diagnosis, all specimens under study were measured, and the minimum and maximum values are used.
The distribution of the prospected sites is plotted using ArcGIS 10.4. (Fig. 1). The type specimens of the new species are deposited in King Saud University Museum of Arthropods (KSMA), Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.
O. omanensis vs. O. formosa (Southern and Central Europe, Russia, Eastern United States, Eastern Canada). Head and mesosoma blue and purplish (dark green and coppery in formosa); scape of antenna red-brown, with black tint apically (yellow, darkening apically in formosa); head width 4.5× eye distance (3.00-3.78× eye distance in formosa); eye 0.75× as height as head (0.55−0.68× as height as head in formosa); corona with structure interrupted (with structure continuous in formosa); pronotum with broadest part behind midlength (with broadest part at midlength in formosa); mesoscutellum almost completely lineate, finely areolate slightly before frenal line (lineate in anterior half to anterior two-thirds, rugulose in posterior half or third in formosa); profemur robust to medium, 1.92-2.00× as long as wide (usually medium to elongated, 1.94-2.33× as long as wide, in formosa).
O. omanensis sp. nov. also resembles the new species O. similis, but differs from it in the following combination of characters: forewing partly infumate, with dark brown to black veins (hyaline in O. similis, with pale brown veins); head with bluish to purplish luster (green and coppery in O. similis); mesoscutellum with green basal half, violet posteriorly (entirely green in O. similis); pronotum distinctly narrow anteriorly, with dense lanceolate whitish setae longitudinally along the middle area, with broadest part behind midlength (distinctly broad anteriorly, with fewer setae along the middle area longitudinally, with broadest part before midlength in O. similis); propodeum medium, ppd.l/msc.l 0.13-15 (large, ppd.l/msc.l 0.17−0.21, in O. similis); volsella of male genitalia with four sharp teeth, aedeagus with parallel outer sides (with five teeth, aedeagus with strongly convex outer margins in O. similis).
Etymology. Named in reference to the country of Oman, where the type specimen was collected.   Description. Female (holotype): Body length 5.6mm (excluding the ovipositor).
Host record. Etymology. This species is named in honour of Pierpaolo Rapuzzi, who participated in the breeding of this species from the dead wood of Acacia sp. Diagnosis. Both sexes (N = 3). See Table 1. Description. Female (holotype): Body length 6.3 mm (excluding the ovipositor).
Male. Similar to female except for second and third metasomal sternites with blue reflection. Genitalia (Fig. 11C, F). Narrowly rounded above; volsella with five sharp, outwardly curved teeth, of which the innermost is minute.
Remarks. This species resembles the Oriental species O. srilankiensis Werner & Peters 2018 (Sri Lanka) in having the body robust; antennal scape red-brown, rest

Discussion
In the present study, four new species of the genus Oodera reared from dead Acacia trees are collected from different regions of Oman and Saudi Arabia (new locality record), with the help of beetle specialists. The study is based on morphological data of 25 specimens (13 females and 12 males). An illustrated key to Arabian species and detailed description of the new species are provided, in addition to analysis with similar valid species. Intraspecific variation is found to be slight as the number of the collected specimens is relatively small because of the rarity of this genus.
The current study is the second contribution to the study of this beautiful and interesting group of Chalcidoidea, covering a new area (Arabia) that was not considered in previous studies (example Werner and Peters 2018). Four new species are added to the world fauna thus increasing the total number to 24 species.
The world species of Oodera was first revised by Werner and Peters (2018), who recognized 20 valid species from which 10 are described as new species. Full descriptions of the new species, and re-description of formerly known ones are given, together with an illustrated key to world species. Few taxonomic changes are also discussed.
The main observation emerging from our study, is the strong correlation of Oodera fauna with the intermediate biogeographical situation of the study area. Almost, all of the studied specimens were collected from southwestern and southeastern parts of Arabia, that are exclusively Afrotropical (Larsen 1984;Burckhardt and Mifsud 1998), only one specimen is collected from Riyadh (Palaearctic). A hypothesis that is supported by Werner and Peters (2018) who concluded that Oodera species seemingly prefer warmer to temperate regions.
However, because of the biodiversity richness of Arabia, due to its rich floristic diversity, more species of this genus are expected to occur. Therefore, further collections and studies are still needed to clarify the distribution of this genus in other parts of this area.