A new species of Aulacus ( Hymenoptera , Aulacidae ) from Hokkaido , Japan

Aulacus machaerophorus sp. n. is described from females collected in Sapporo, Hokkaido, Japan. This new species has some interesting characteristics such as a very short ovipositor, absence of a ventral lobe and ovipositor guide on hind coxa, and smooth and shiny axillula, and is considered to be closely related to Nearctic species, A. schiffi. A key to three Japanese species of Aulacus is given.


Introduction
Aulacus Jurine, 1807 is composed of 78 extant species and has been recorded from all biogeographical regions except Antarctica and the Afrotropical (Chen et al. 2016).Wasps of this family are koinobiont endoparasitoids and use Xiphydriidae (Hymenoptera) and Buprestidae and Cerambycidae (Coleoptera) as hosts (Chen et al. 2016;Jennings and Austin 2004;Smith 2001).Aulacidae consists of two genera, Aulacus and Pristaulacus.Aulacus is distinguished from Pristaulacus by the following features: occipital carina absent; tarsal claw with a basal tooth or none; pronotum without a dentiform process along latero-ventral margin; petiole slender, at least 2.5 times as long as wide.Aulacus is considered to be a paraphyletic group with respect to Pristaulacus (Turrisi et al. 2009).
Seven species of Aulacus have been recorded from the Palaearctic Region, with two from Japan, A. japonicus Konishi, 1990 from Iwate, Tohoku and A. uchidai Turrisi and Konishi 2011 from Hokkaido (Konishi 1990;Turrisi and Konishi 2011).Recently, we collected Aulacus specimens from Sapporo, Hokkaido, and found that they have distinctive and peculiar characteristics separate them the known species.Here we describe a new species based on these specimens.

Materials and methods
Specimens used in this study are dried except one which is preserved in 99% ethanol.They are deposited as follow: Hokkaido University Museum, Sapporo, Japan (SEHU); the Ehime University Museum, Matsuyama, Japan (EUM); and National Museum of Natural History, Smithsonian Institution, Washington, DC, USA (USNM).Morphological technical terms follow Huber and Sharkey (1993) and surface sculpture follows Eady (1968).The methods of measurements follow Konishi (1990) and Smith (2008), and measured traits are shown in Fig. 1.In this paper, we use the following abbreviations: OOL = distance between outer margin of posterior ocellus and eye; POL = distance between inner margins of posterior ocelli.Most photographs (Figs 1-14) were obtained at the Laboratory of Environmental Entomology, Ehime University, using a Nikon Digital Sight DS-Fi1 camera attached to a Leica S8APO stereomicroscope.Fig. 15 was taken under a digital microscope HiROX KH-1300 and the image captured with the 2D measurement software SHX-13M ver.2.9.0.Several partially focused images were combined and post-processed using Adobe Photoshop® CS6.Description of female.Length: 4.1-6.5 mm Color: Black; median portion of mandible yellowish brown; apical 1/3 to entire scape yellowish brown; apical portion of pedicel yellowish brown; trochanter yellowish brown to black; basal and apical portions of femora yellowish brown; fore tibia yellowish brown; mid tibia yellowish brown, sometimes black with basal and apical portions yellowish brown; hind tibia with basal and apical portions yellowish brown; fore and middle tarsi yellowish brown to light yellowish brown; hind tarsus yellowish brown, sometimes dark yellowish brown; wings hyaline, stigma and veins black; setae silver, setae on mandible gold.

Genus
Head glossy (Figs 3-7), 0.6-0.7 times as long as wide; lower area of gena coriaceus; malar space 0.4-0.5 times as long as eye height; head length behind eye in dorsal view 0.4-0.5 times as long as eye height; lower interocular distance 1.2-1.4times as long as eye height; posterior margin of head weakly concave in dorsal view; occiput and postocciput smooth with dense setae and punctures; temple smooth; vertex smooth, with setae and sparse punctures, coriaceus between eye and posterior ocellus; OOL:POL=1:1; frons coriaceus and sparsely punctate with setae; antennal socket situated at about lower level of eye, separated from anterior tentorial pit by its own diam- eter; face densely punctate with setae and coriaceus-granulate; clypeus granulate and densely punctate with setae, with a protuberance situated at middle of apical margin; punctures on face and clypeus much stronger and denser than on temple; mandible smooth, basal area and upper half with some setae; antenna (Fig. 7) with fine hairs, 3.1-4.4times as long as head length; pedicel 1.4-1.9times as long as wide; 1st flagellomere 3.0-4.0time as long as wide, 0.6-0.7 time as long as 2nd.
Biology.All specimens used in this study were collected on the tree trunk of a blighted broad leaf tree in a broad-leaved forest.
Etymology.From the Latin machaerophorus, meaning bearing a short sword.This new species has a short ovipositor like a short sword.
Remarks.This new species possesses the following peculiar features: frons without transverse carina and rugulose sculpture; axillula smooth, shiny; hind coxa without ventral lobe and ovipositor guide; ovipositor very short (0.2-0.3 times as long as fore wing); apical portion of ovipositor with some short setae.
In Aulacus species so far described, a Nearctic species, A. schiffi Smith, 1996 is considered to be most closely related to A. machaerophorus.They share the short ovipositor; hind coxa without projecting ventral lobe and ovipositor guide; smooth frons without transverse carina; and ovipositor with setae (Smith, personal communication).Among these characteristics, the presence or absence of setae on ovipositor has not been reported in other Aulacus species and therefore needs further examination.Aulacus machaerophorus can be separated from A. schiffi by the absence of diagonal carinae on the axillula, the shorter ovipositor (ovipositor is 0.5 times as long as fore wing in A. schiffi) and wing venation (A.schiffi has a longer discal cell, 2Rs+M between the discal and submarginal cells is much shorter, and 2r-m is absent).This relationship of A. machaerophorus and A. schiffi is suggest close relationships of some of the fauna and flora of eastern Asia and eastern North America.For example, relationship of North American and eastern Asian species of Stronglygaster (Tenthredinidae) (Smith and Naito 1995) and example of the flora see Tiffney (1985).
Other Palaearctic species have rugulose frons with transverse carina judging from figures in Chen et al. (2016) and Sundukov and Lelej (2015).On the other hand, Australian and Nearctic Aulacus species have the frons with or without transverse carinae and the hind coxa with or without a ventral lobe and ovipositor guide (Jennings et al. 2004;Smith 2008).
This new species can be distinguished from two Japanese species by the following key.

Figure 1 .
Figure 1.Methods for measurements of wing venation: a Rs between 1R and Rs+M b M between Rs+M and M+Cu.