Myrmica onoyamai

The nest of this species was found in anthropogenic conditions that were quite exposed, hot and dry compared to general surrounding woodland, and the location may not be typical for this species. It was under a small stone in a pile of sandy gravel dumped by the side of the road, possibly to grit the road in icy conditions, although it had been there some time because its surface was covered in moss and lichens. The road was in a river valley in an area of mixed woodland at an altitude ca. 900 m, about 10 m from the river. We suggested that M. onoyamai living in more natural conditions might be associated with warmer exposed biotopes such as sub-alpine grassland and sandy screes at the base of cliffs. (Radchenko and Elmes 2010)

Identification
A member of the schencki group. Its workers and queens well differ from those of all other members of this group by a distinctly wider frons and by proportionally less extended frontal lobes: in workers mean FI 0.35, mean FLI 1.20 vs. mean FI < 0.33, mean FLI > l.28 in other schencki-group species. The male of M. onoyamai most resembles males of Myrmica koreana, but differs from them by shorter hairs on the head margins, by the much less sculptured, almost smooth scutum and scutellum, by the not angled dorsal plane of the scape and by wider postpetiole. (Radchenko and Elmes 2010)

Distribution based on Regional Taxon Lists
Palaearctic Region: Japan.

Nomenclature

 *  onoyamai. Myrmica onoyamai Radchenko & Elmes, in Radchenko, Elmes & Alicata, 2006: 507, figs. 23-42 (w.q.m.) JAPAN. See also: Radchenko & Elmes, 2010: 208.

Worker
Head longer than broad, with slightly convex sides, straight occipital margin, and quite broadly rounded occipital corners. Anterior clypeal margin broadly rounded and shallowly notched medially. Frontal carinae feebly curved, frons wide (the widest among all known species of the schencki-group), frontal lobes narrow, not extended. Scape strongly angled at the base, with small vertical dentiform ridge forming a small shield on the vertical face of foot.

Alitrunk with weakly convex promesonotal dorsum; promesonotal suture visible from above; metanotal groove very shallow. Propodeal spines long, acute, straight, not widened at the base, slightly divergent (seen from above), projecting backwards at an angle less than 45°. In profile, anterior surface of petiole slightly concave, meeting the dorsal surface at a blunt rounded angle; dorsal surface convex and gradually sloping posteriorly, without dorsal plate. Postpetiole somewhat shorter than high, with convex dorsum. Spurs on middle and hind tibiae well developed and pectinate.

Only frons with sinuous longitudinal rugae, remainder part of head dorsum with reticulation. Antennal sockets surrounded by concentric rugae. Clypeus with longitudinal rugae, frontal triangle smooth. Sides of alitrunk with quite coarse sinuous rugae, promesonotal dorsum with reticulation. Petiolar node with sinuous longitudinal rugae, its dorsum also has reticulation, postpetiole with longitudinally-concentric rugae. Surfaces between rugae on head and alitrunk smooth and shiny, those on petiole and postpetiole punctured.

Head margins with fairly short suberect hairs, hairs on alitrunk and waist erect, longer and more abundant; scape with suberect, and tibiae with subdecumbent hairs. The overall colour brown, head dorsum blackish-brown, appendages yellowish-brown.

Queen
Generally like workers in shape of head and scape, colour and pilosity of the body except they have coarser sculpture, especially on the alitrunk, petiole and postpetiole. 'The frons is slightly relatively wider and the propodeal spines are blunter and wider at their base.

Male
Head longer than broad, with convex sides and occipital margin, and gradually rounded occipital corners; anterior clypeal margin widely rounded and shallowly notched medially. Scape short, but longer than first and second funicular segments together, very feebly and gradually curved. Antennae 13-segmented, with 5-segmented club.

Alitrunk relatively long, scutum slightly convex, scutellum does not project dorsally above scutum when seen in profile. Propodeum with blunt rounded tubercles. In profile, petiole relatively long and low, with rounded dorsum of node, its anterior surface almost straight and quite steep; postpetiole higher than long, with weakly convex dorsum.

Head dorsum finely but densely punctured, frons and temples with very fine striation. Scutum and scutellum smooth and shiny, only posterior part of scutum and posteriolateral parts of scutellum with very fine striation. Propleura smooth and shiny, only with fine striation on their posterior parts; mesopleura and propodeum not coarsely rugose. Petiole and postpetiole smooth and shiny.

Type Material
Radchenko and Elmes (2010) - Holotype, w, Japan, Yalllamashi Pref., ea 15 km NE of Sudama interchange, nr. Hokuto City, By Shiokawa riv. nr. Shiokawa Dam. c. 900 III No. J-99, 24.vii.2002, leg. G. W. Elmes ; paratypcs: 64 w, 25 g, 1 m from the nest of the holotype (London, Kiev, Elmes, Helsinki). Unfortunately, in the original description of this species (Radchenko, Elmes and Alicata 2006) we wrongly gave the type locality as "Japan, lsI. Honshu, Nagano Pref., about 11 km E of Matsumoto on road to Tobira pass, ca. 1400 m a.s.l.". BMNH,,. This site where we also collected Myrmica samples, is some tens of kilometres from the actual site on Honshu Island where we collected the holotype series.

Etymology
Radchenko and Elmes (2010) - we dedicated this species to the Japanese myrmecologist Prof. Keiichi Onoyama of Obihiro University, Japan.