Gonatopus tagoi Mita, 2024, new species

Group 4, Gonatopus tagoi, new species (Figs 1–4, 10) Description. Holotype female. Apterous. Head (Fig. 2) excavated, 0.47× longer than wide; frons smooth with ocellar triangle sculptured; inner orbit of eye and vertex granulated; frontal line complete; malar space smooth; gena smooth; OL = 3.5; POL = 1.5; OOL = 9.0; maximum diameter of anterior ocellus 1.0; occipital carina absent; antennae distally thickened; each antennomere showing following ratio: 9.5: 6.5: 21.0: 13.0: 10.0: 9.0: 7.5: 7.5: 6.5; 10.0. Palpal formula 6/3. Pronotum (Figs 1, 3, 4) 1.1× longer than wide, smooth; anterior transverse groove and strong transverse impression present. Mesoscutum rugose, not granulated; lateral pointed apophyses absent; mesoscutellum smooth, almost flat in lateral view; mesopleuron transversely striate and granules; sides of mesopleuron almost flat (Fig. 3); meso-metapleural suture absent, but indicated among keels. Metanotal region roughly sculptured, flat in lateral view; metapectal-propodeal complex striate, partly granulate except anterodorsal surface smooth. Protarsomeres showing following ratio: 92: 18: 24: 104: 150: T1 0.88× T4; T3 producing into one hook; chela (Fig. 10) with T5 bearing two rows of 17 + 18 lamellae, one separated lamellae; apex of T5 bearing approximately 25 lamellae; enlarged claw with one large subapical tooth and one row of 12 lamellae. Tibial spurs1/0/1. Color. Head black except anterior part of frons, malar spaces, and clypeus testaceous, genae brown; mandibles testaceous with reddish brown teeth; antenna brownish black excluding scape, pedicel, basal margin of F1 testaceous, apex of F8 brown; pronotum light brown, with surface around transverse impression darkened; propleuron dorsally black, ventrally dark brown; mesoscutum testaceous; mesoscutellum, mesopleuron, metapectal-propodeal complex black; legs mostly yellowish brown but profemur, protibia and basitarsus brownish; metasoma brown except petiole black. Measurements (in mm). Head 0.57 long, 1.22 wide; antenna 2.72; mesosoma 2.43; procoxa 0.90; protrochanter 0.67; profemora 1.38; protibia; 1.27; T5 0.75; total body length 4.70. Male. Unknown. Specimens examined. Holotype: ♀,“JPN, Saitama Pref., Misato-shi, dry riverbed of Edo-gawa Riv., 25. VII. 2004, T. Tago leg.” (ELKU). Distribution. Japan (Honshu). Hosts. Unknown. Etymology. The species name is derived from Toshihiro Tago, the collector of the holotype. Remarks. The new species is classified to Gonatopus species group 4 because the holotype is apterous female with following characters: palpal formula 6/3; pronotum crossed by a strong transverse impression; enlarged claw with lamellae and one large apical tooth. Compared to the Palaearctic and Oriental species of group 4, there are no closely related species to the new species. According to the key (Eastern Palaearctic: Olmi & Xu 2015; Oriental: Xu et al. 2013), it can be compared to G. gobiensis (Ponomarenko, 1979) (usually testaceous species with meso-metapleural suture distinct and producing mesoscutellum), G. asiae Olmi, 1984 (testaceous species with lateral pointed protrusion of mesoscutum and distinct meso-metapleural suture) or G. insulae Olmi, 1984 (testaceous species with sides of mesopleuron distinctly rounded). However, it is clearly differentiated by the bicolored body, the inclined mesoscutellum, the flat metanotum, the flat mesopleuron and the laterally fully costate but longitudinal carinae and furrow missing on metapectal-propodeal disc. The holotype was collected by net-sweeping from the grassland on the dry riverbed of the Edo-gawa River, Central Honshu.