Review of the Asian wood-boring genus Euxiphydria ( Hymenoptera , Symphyta , Xiphydriidae )

Five species of Euxiphydria are recognized, E. leucopoda Takeuchi, 1938, from Japan, E. potanini (Jakovlev, 1891) from Japan, Russia, Korea, and China, E. pseudoruficeps Okutani, 1966, from Taiwan, E. vietnamensis, sp. n. from Vietnam, and E. shaanxiana, sp. n., from China. Euxiphydria subtrifida Maa, 1944, is considered a new synonym of E. potanini. A key and illustrations are given to distinguish the species.


Introduction
Euxiphydria is an exclusively eastern Asian genus occurring from Japan and eastern Russia south to China, Vietnam, and Taiwan.Three species were listed by Smith (1978) and Taeger et al. (2010).Earlier keys to species by Gussakovskij (1935), Takeuchi (1938) and Maa (1944Maa ( , 1949) ) included from two to four species in the genus.An ad-labial palpus (Figs 20,35) with three palpomeres, first two palpomeres slender and third palpomere dilated, oval, with sensory pit.Forewing (Figs 1,23,36) with cell R closed, vein 2A+3A complete.Hind wing (Figs 1,23,36) with cell R closed, cells Rs and M present; anal cell present, petiole subequal to width of cell.Tarsal claws with long inner tooth near center of claw, about half length of outer tooth; claw of hind legs larger than those of fore-and midlegs.Tergite 10 posteriorly tubuliform, strongly protruding caudad.
Discussion.The above combination of characters will separate Euxiphydria from other xiphydriid genera.The only other genus with four maxillary palpomeres and three labial palpomeres is Carinoxiphia Wei (in Wei and Xiao 1999).In Carinoxiphia, the third labial palpomere is slender, the same width as the first two palpomeres, the radial cell of the forewing is open at its apex, the tarsal claws have a minute inner tooth, and the wings are hyaline.Other xiphydriid genera have a different palpomere formula, commonly with three or five maxillary palpomeres, have a slender third labial palpomere, are usually black with various white, yellow, or orange markings, the eyes are larger, commonly converging with the lower interocular distance equal to or shorter than the eye height, the head behind the eye in dorsal view is commonly strongly narrowing with the distance behind the eyes shorter than the eye length, the antennae various but commonly filiform, and the tarsal claws may be simple or with the inner tooth nearly as long as the outer tooth and close to the outer tooth.
Discussion.Euxiphydria leucopoda was transferred to Hyperxiphia by Maa (1949) without explanation, but it is actually an Euxiphydria as described by Takeuchi (1938).Euxiphydria leucopoda has three labial palpomeres with the third clavate and four maxillary palpomeres, as well as other characteristics of Euxiphydria except for the head which is short and narrowing behind the eyes in dorsal view.Hyperxiphia has three labial palpomeres of equal width and has five maxillary palpomeres.The holotype is a small specimen, about 9 mm long.The specimen from Mt. Haku is 12 mm long.Takeuchi (1938) described a variety, Euxiphydria leucopoda var.nakanishii, which he stated to be similar in structure to the typical, but smaller, the hind basitarsomere distinctly shorter than the following tarsomeres together, and differing in color with the head entirely black except for pale yellow below the antennae.This is actually a different species and genus and was correctly placed in Hyperxiphia by Maa (1949) For other subsequent references, see Smith (1978).
The lectotype of Xiphydria ruficeps Matsumura, described from "Hokkaido (Sapporo)" is at Hokkaido University, Sapporo, Japan.The number of specimens was not given by Matsumura, but the treatment of Matsumra's xiphydriid types by Watanabe (1956) serves as a lectotype designation.
Xiphydria akazui first appeared in Matsumura (1932) wherein Matsumura cited it as "Xiphydria akazui (X.ruficeps Mats.)" in the Japanese section (p.31), although only "Xiphydria akazui" was given in the English part of the book (p.44).In the footnote on page 44, Matsumura mentioned "This may be a form of X. ruficeps Mocz [sic]."Matsumura may have recognized that his name Xiphydria ruficeps was preoccupied by X. ruficeps Mocsáry, and thus merely proposed a replacement name, X. akazui, for his species rather than intending to describe a new species.He did not specifically state that X. akazui was a new species or that it was a proposal of a new name, but he follows with a brief description.Xiphydria akazui is entered in the catalogs by Smith (1978) and Taeger et al. (2010) as a new species, not a replacement name.If regarded as a new species, the type specimen of X. akazui, may be the same specimen as the type of X. ruficeps Matsumura.Indications supporting that Matsumura (1932) proposed a new name and did not intend X. akazui to be a new species are that Watanabe (1956) did not give it in his list of Matsumura's type specimens of Xiphydriidae.Matsumura always indicated that taxa were new when describing them, and there are no specimens of xiphydriids labeled X. akazui in Matsumura's collection at the University of Hokkaido; there is only one specimen with a red label and Watanabe's identification label of X. ruficeps (Ohara, pers.comm.).
We have not examined the holotype of X. potanini Jakovlev.Based on the description (Jakovlev 1891), especially the black and red color of the head and black legs, it cannot be the other species treated here.The description is sufficient to place X. potanini as the widespread species treated here.
We conclude that all species listed in the synonymy are conspecific and that characters previously used to separate them are variable, agreeing with Takeuchi (1938) and Maa's (1949) study of variation.Size does not mean much in xiphydriids where the same species can vary considerably in length.We have checked about 48 females and males, and they are 10-20 mm long.Number of antennomeres in multiarticulated species can vary.Of 30 specimens, 56 antennae were intact, and they have 13 antennomeres (13 antennae), 14 (34), 15 (7), and 16 (2).Of the 26 specimens with both antennae intact, five specimens have different number of antennomeres (13 and 14 in all cases) on each antenna.Watanabe (1956) also noted that number of antennomeres can vary from 13-15.The wing color and sculpture of the mesopleuron can vary slightly, the latter sometimes slightly denser in smaller individuals.Wing venation can vary in xiphydriids, as pointed out by Smith (2008), and shapes of the cells as pointed out by Semenov and Gussakovskij (1935) are rather vague.
Matsumura's species, X. ruficeps (and X. akazui if not considered a replacement name), is with little doubt synonymous with E. potanini.The descriptions are brief, but compare well with E. potanini, and the specimens are from Hokkaido and Honshu where nothing else can be confused with X. potanini.Zirngiebl (1937) described E. maidli from eastern Siberia.There is nothing in this area that can be confused with E. potanini.Zirngiebl's description agrees with E. potanini, and comparison with images of the paratype (S.Schmidt, pers.comm.)confirmed its synonymy.
Euxiphydria subtrifida was described from males from Chekiang, China.Even Maa (1949) had reservations about its validity, stating that it was probably inseparable from E. ruficeps.Males we have seen of E. potanini from China agree with Maa's description, and we therefore propose its synonymy under E. potanini.Diagnosis.Length, 11.5 mm.Black except head entirely orange (Fig. 24).Forewing uniformly lightly infuscated; hind wing somewhat paler on basal half (Fig. 23).An- tenna (Fig. 29) with 14 or 15 antennomeres; length of first four antennomeres as 1.0:0.3:0.8:0.4.Sculpture on frons consisting of straight to irregular carinae, not reticulate (Fig. 28).Head from above gently rounded behind eyes, distance behind eyes much longer than eye length (Fig. 27).Malar space narrow between eye and antennal groove, much shorter than width of groove (Fig. 28).Axilla and mesoscutellum with irregular longitudinal carinae, posterolateral and posterior sides smooth and shiny (Fig. 26).Mesepimeron with long, distinct, almost parallel carinae (Fig. 25).Hind basitarsomere subequal to length of remaining tarsomeres combined.Length of sheath slightly shorter than length of basal plate.Male unknown.
Discussion.The two specimens examined are very similar, though the carinae on the frons and mesoscutellum of the holotype are somewhat more distinct than in the other specimen.
Description.Female.Length, 14.0 mm.Color.Head red; black on ocellar area and extending posteriorly to near occiput through center of postocellar area (Figs 33,34).Abdomen black with white spot on side of eighth tergite (Fig. 30).Legs black with basal third of hind tibia and hind basitarsomere white (Fig. 30).Wings uniformly, lightly infuscated; hind wing somewhat more hyaline on basal half.
Head.Antenna with 19 antennomeres; length of first four antennomeres as 1.0:0.4:0.9:0.5.Frons with curved almost parallel carinae (Fig. 34).Upper half of gena and vertex from posterior margin of lateral ocelli smooth, shiny.Malar space between eye and antennal groove narrow, much less than width of groove (Fig. 34).Width of gena behind eyes about 1.4× eye width.Head from above straight behind eyes, distance behind eyes slightly longer than eye length (Fig. 33).
Abdomen.Basal plates densely punctate anterolaterally, shiny and with few punctures on medial posterior portion (Fig. 32); rest of abdomen shiny, finely punctate.Length of sheath slightly shorter than length of basal plate.
Male.Unknown.Etymology.Named for the country of collection.Discussion.The white lateral spot on the eighth abdominal tergite, partly white hind tibia and hind basitarsomere, the curved, almost parallel carinae on the frons, the head in dorsal view long behind the eyes, and the completely sculptured axilla and mesoscutellum will distinguish E. vietnamensis from other Euxiphydria species.This is the southernmost record for the genus.Head.Antenna with 15 antennomeres; length of first four antennomeres as 1.0:0.4:0.9:0.4.Frons reticulate in front of ocelli and between ocelli and eyes, with irregular almost parallel carinae dorsal to and between antennae (Fig. 41).Upper half of gena and vertex from posterior margin of lateral ocelli smooth, shiny.Malar space between eye and antennal groove narrow, much less than width of groove (Fig. 41).Width of gena behind eyes about subequal to eye width.Head from above rounded and narrowing behind eyes, distance behind eyes about equal to eye length (Fig. 40).
Abdomen.Basal plates mostly smooth and shining, finely punctate anteriorly, (Fig. 39); rest of abdomen shiny, finely punctate.Length of sheath subequal to length of basal plate.
Male.Unknown.Etymology.Named for the Chinese province in which it was collected.Discussion.The red head and black thorax, abdomen, and legs are similar only to E. potanini.In E. shaanxiana, the head is entirely red, behind the eyes in dorsal view sharply rounded with the distance about equal to the eye length, the sculpture on the frons consists of irregular carinae, and the axillae and mesoscutellum are more finely sculptured with the posterior portion smooth and shiny.