A remarkable new genus and species of Euryproctini (Hymenoptera: Ichneumonidae, Ctenopelmatinae) from Thailand

. Rhytidaphora Reshchikov & Quicke gen. nov. (type species Rhytidaphora thailandica Reshchikov & Quicke gen. et sp. nov.) from Thailand is described and illustrated. It belongs to the tribe Euryproctini of the subfamily Ctenopelmatinae (Hymenoptera, Ichneumonidae) based on the absence of glymma and the subapical notch on the ovipositor. The new taxon differs from all other genera of Euryproctini by the occipital carina being broadly incomplete dorsally, the hypostomal carina joining the occipital carina shortly before the base of the mandible, distinctly pectinate tarsal claws, and immovably fused and strongly sculptured second and third metasomal tergites.

Members of the Ctenopelmatinae are overwhelmingly endoparasitoids of sawfl y larvae. Together with their hosts these wasps display distribution patterns with the highest diversity in the North temperate zone. Their tropical fauna most probably developed from invasions from the Holarctic along mountain ranges (Malaise 1945;Smith 2011;Reshchikov 2015). Thus, 140 species of Euryproctini are recorded from the Holarctic region and only 9 species are known from the Oriental region (Yu et al. 2016;Sun et al. 2021a).
Here we describe a new genus and species of Euryproctini from Thailand based on recently collected specimens. Its morphology suggests that it is a member of the Euryproctini, where we place it. The tribe can be characterized by the absence of glymma and the subapical notch on the ovipositor. The fi rst character state is broadly derived in the subfamily; however, other tribes have only a few genera with the glymma absent. Thus, euryproctines (except some Hadrodactylus Förster, 1869) lack the T2 ridges between the anterior margin and the spiracle, differing from the members of the tribe Ctenopelmatini. Ovipositor structure differs between Euryproctini and Pionini Smith & Shenefelt, 1955; the latter have a needle-like ovipositor without a subapical notch. Seleucus Holmgren, 1860, which was recovered by Quicke et al. (2009) as a sister group to Euryproctini, also has the ovipositor with the subapical notch and the glymma absent, but the second and third metasomal tergites (T2-3) are exceptionally elongated (Holmgren 1860). Our new genus and the species described here were readily recovered within Euryproctini in our phylogenetic analysis (see discussion). They differ from all other known members of the tribe Euryproctini by the occipital carina being broadly incomplete dorsally, joining the hypostomal carina shortly before the base of the mandible, distinctly pectinate tarsal claws, and immovably fused T2 and T3.

Material and methods
This work is based on material collected by the TIGER project (http://sharkeylab.org/tiger) in Chae Son National Park in Lampang Province in 2007, and by the research group of the third author in Doi Phu Kha National Park, Nan Province in 2020.
Type specimens are deposited at the following collections: CUMZ = Collection of the Insect Museum, Chulalongkorn University Museum of Natural History, Bangkok, Thailand QSBG = Queen Sirikit Botanic Garden, Chiang Mai, Thailand A 407 base pair sequence partial 3′-barcode for the new species was obtained following a failed fi rst sequencing run. GenBank accession numbers and provenances of the taxa included in the analysis are given in Table 1. A molecular dataset of the barcode region of cytochrome oxidase c subunit 1 (CO1) was compiled for a total of 46 species of Ctenopelmatinae, two Tryphoninae Shuckard, 1840, which were used for rooting the tree, plus a species of Scolomus, a genus originally placed in Ctenopelmatinae but subsequently transferred to Metopiinae; however, placement of the latter is still uncertain (Bennett et al. 2019).   (2022) Most of the recent DNA extractions were carried out using normal procedures for 96-well plates (Ivanova et al. 2006), and PCR and sequencing reactions were carried out using standard protocols (Hajibabaei et al. 2005). Most sequences were obtained using the LCO-HCO primer pair combination (Folmer et al. 1994: LCO 5′-GGT CAA CAA ATC ATA AAG ATA TTG G-3′, HCO 5′-TAA ACT TCA GGG TGA CCA AAA AAT CA-3′) or, less often, LepF1-LepR1 (Smith et al. 2005: LepF1 5′-ATT CAA CCA ATC ATA AAG ATA TTG G-3′, LepR1 5′-TAA ACT TCT GGA TGT CCA AAA AAT CA-3′). Sequence alignment was carried out manually and was largely trivial as there were no indels. Sequences were analysed using maximum likelihood with the programme RAxML ver. 8.2.X (Stamatakis 2014), using a GTR + G rate model with the three codons as separate data partitions, with 100 replicates with two threads. Trees were visualised using Figtree (ver. 1.4.3) (Rambaut 2016).
The morphological terminology follows Gauld (1991). Images were taken using a Leica M205 C microscope with Montage multifocus, Interactive measurement and fusion optics stereo microscope combined with Leica Application Suite. Metasomal tergites and sternite are abbreviated as T and S, respectively.

Etymology
The generic name Rhytidaphora derives from Greek "ρυτίδα" -"wrinkle" and "φέρω" -"bear", referring to the sculpture of the metasoma. The gender is feminine.
COLORATION. Yellow, except for the following which are marked with black: antenna (dorsally), teeth of mandible, dorsal part of head, pterostigma, hind coxa dorsoapically, hind femur and tibia apically, hind tarsus (except fi rst tarsomere basally), lateral parts of mesoscutum entirely and its anterior medial part, pair of spots on T3 and T4 (Figs 1-2).

Male
Unknown.

Distribution
Thailand.

Molecular analysis
As in the only previous study in which Ctenopelmatinae were relatively well represented (Quicke et al. 2009), the molecular analysis did not recover any large ctenopelmatine tribes as monophyletic (Fig. 3). The placement of Scolomus within Ctenopelmatinae, even though this genus has been transferred to Metopiinae (Gauld & Wahl 2006), is consistent with the idea that Metopiinae may be derived from within the Ctenopelmatinae (Quicke et al. 2009). The Euryproctini as currently constituted were recovered spread across the tree in fi ve separate clades but with low support. Nevertheless, nine of the included euryproctine genera formed a monophyletic grouping (Fig. 3, top) including Rhytidaphora gen. nov., and is therefore consistent with the placement of the new genus based on our morphological assessment.

Discussion
Members of Euryproctini can be recognized from other Ctenopelmatinae by the combination of: absence of glymma and of tyloids on the male antenna; the epicnemial carina reaching the anterior margin of the mesopleuron; the groove between metapleuron and propodeum shallow and not U-shaped; the ovipositor with subapical notch; and tarsal claws not pectinate. Otherwise, only Occapes Townes, 1970 has pectinate claws within Euryproctini. In our analysis Rhytidaphora gen. nov. is readily recovered within Euryproctini (Fig. 3), and actually nested among Synomelix Foerster, 1868 species. However, a number of unique character combinations suggest that Rhytidaphora is a new genus and not actually a derived species of Synomelix. Species of Synomelix have the mandibular teeth of equal length (lower teeth longer in Rhytidaphora), fore wing with areolet present (absent in Rhytidaphora), occipital carina complete. The pectinate tarsal claws can be considered as a possible synapomorphy for Occapes and Rhytidaphora. In Syndipnus Förster, 1868 and the newly described genus, T2 and T3 are immovably fused (Fig. 2D). This character occurs also in the Rhorus mesoxanthus (Gravenhorst, 1829) speciesgroup of the Pionini (Reshchikov et al. 2017b) and a few other ichneumonids. The distinctly striate deep transverse impressions of T1-5 (Fig. 2F) is a unique character within Euryproctini and Ctenopelmatinae in general. There are only shallow transverse grooves on T1-3 in Rhinotorus Foerster, 1869 (Reshchikov 2016) and Gilen Reshchikov & Achterberg, 2018(Reshchikov & van Achterberg 2018. There is also similarity with the euryproctine genus Hypsantyx Pfankuch, 1906, which also has a huge petiolar area on the propodeum (Fig. 2C, F).