Strumigenys kumadori

A close relative of Strumigenys lewisi, this species was informally noticed for decades and finally clearly separated by notable differences between the queens' of these two species.

It is mainly found in leaf-litter of mountainous forests in Korea. They make their colony in the rotten trees, beneath barks, rotten acorns, cracked rocks, and fallen leaves under stones located in shady forests. This species was previously known as Strumigenys sp. by Choi (1995) in Korea (Dong & Kim, 2020).

Identification
Dong & Kim (2020) - This species can be distinguished from other Korean Strumigenys species by the combination of following characteristics:
 * Head distinctly longer than wide with deeply concaved occipital margin.
 * Apicoscrobal hair distinctly long, usually flagelliform, rarely filiform.
 * Clypeus fan shaped.
 * Mandibles long, linear and elongated.
 * Pronotal humeral hair flagelliform.
 * Posterior margin of propodeal lamella straight or slightly convex, not distinctly concave.

This species is morphologically very similar to its sibling species, Strumigenys lewisi Cameron, 1886, making it very hard to distinguish them from each other, especially for the worker caste. Gynes are much easier to distinguish from S. lewisi by following combination of the characteristics. Strumigenys kumadori: Compound eyes distinctly larger than S. lewisi. Each ocellus with separate dark patterns. Promesonotal suture distinct and concave. Posterior margin of scutellum perpendicular in lateral view.

Yoshimura and Onoyama (2007) - A member of the godeffroyi complex in the Strumigenys godeffroyi-group. Strumigenys lewisi and Strumigenys kumadori are very similar to Strumigenys geminata. S. lewisi and S. kumadori can be separated from the latter by having a more feeble propodeal spine and the lateral surface of pronotum completely reticulate-punctate or at most with a small smooth patch above the fore coxa.

Strumigenys kumadori is distinguished from S. lewisi by the following characters: 1) in the workers, all of two paired hairs on the apicoscrobe and anterior portion of the mesonotum are long and distinctly flagellate in the former, but both of the hairs are plumose-filiform or filiform in the latter (Figs 12,13 – see figures in caste section below and in the caste section for Strumigenys lewisi), 2) the eyes of the queens are relatively large in the former, but relatively small in the latter (Fig. 56), 3) the lateral ocelli of queens are distinctly large (Figs 20, 55) with pigmented outer margins in the former, but relatively small (Figs 26, 55) or vestigial and not distinctly bordered with pigment around them in the latter, 4) the mesoscutum of queen in dorsal view is wide (MsWI>63) and weakly constricted at posterior 1/3, and lateral corners by the constriction are not angular in the former, but narrow (MsWI<63) and strongly constricted, and the lateral corners are angular in the latter, 5) the transverse furrow on mesoscutum of queen is curved posteriorly in the former (Fig. 19), but nearly straight in the latter (Fig. 25), 6) fore wings of queen are relatively broad in the former (Fig. 41), but are reduced and narrow in the latter (Fig. 43), 7) the radial vein on the hind wing does not reach the costal margin in the former (Figs 41, 42), but does so in the latter (Figs 43, 44), 8) the mandible of male is relatively narrow in the former (Figs 30, 32), but is relatively wide in the latter (Figs 36, 38), 9) on the male genitalia in lateral view, volsella is gently curved and the corner is not broadened in the former (Fig. 46), but is abruptly curved and the corner is distinctly broadened in the latter (Fig. 50).

In the present study, the characters in the queen have most distinctly separated between the two species, S. kumadori and S. lewisi. The eyes, ocelli, mesonotum, and wings are useful characters to distinguish these two species. While much developed, the male's mesosoma did not provide useful characters to separate the two species, while the queen's one did. The reduced male mandible, however, provided useful distinguishing characters.

Distribution based on Regional Taxon Lists
Palaearctic Region: China, Japan, Republic of Korea.

Biology
Our collection data of the colonies suggest polygyny occurs in S. kumadori only in large colonies with more than 37 workers. Masuko et al. (1985) reported that S. kumadori is predominantly monogynous, and further reported (1999) that 17% of 96 colonies of S. kumadori contained two or more queens regardless of the number of workers, and demonstrated that even in polygynous colonies a single individual in each colony was fertile (i.e., functional monogyny).

The distribution areas and sites of S. kumadori and S. lewisi. overlap in Honshu, Kyushu, and Korea (JADG, 2003a, 2003b, 2003c; Terayama, 1999). We additionally confirm the presence of both species in Taiwan. Nest habitats of the two species are the same or very similar (Masuko et al., 1985), and we actually confirmed that both species were collected from a single leaf litter sample taken from a quadrat of 0.5m x 0.5m. Therefore, these two have completely sympatric distribution.

Nomenclature

 *  kumadori. Strumigenys kumadori Yoshimura & Onoyama, 2007: 668, figs. 3-9, 17-22 (w.q.m.) JAPAN.

Worker
HL 0.67, HW 0.45, CI 67.7, ML 0.32, MI 48.5, SL 0.36, SI 80.5, DSA 3 L 0.15, DSA 3 W 0.19, DSA 3 I 127.3 (Holotype worker). HL 0.62 - 0.67, HW 0.44 - 0.47 CI 69.0 - 72.3, ML 0.30 - 0.32, MI 46.0 - 50.5, SL 0.36 - 0.39, SI 79.4 - 86.6, DSA 3 L 0.13 - 0.15, DSA 3 W 0.17 - 0.20, DSA 3 I 113.6 - 140.0 (6 measured).

Ventrolateral margin of head at level of eye not extended outward. Antenna consisting of 6 segments. Fully closed mandible in full-face view curvilinear. On the mandible, a distinct, long and spiniform preapical tooth present close to apical teeth. Apical teeth consisting of two distinct spiniform teeth and three small intercalary teeth between them: basal one of the two spiniform teeth longer than the apical one: basal one of the three intercalary teeth distinctly smaller than apical two. With mesosoma in lateral view, the diameter of the excavated area of mesopleural gland moderate, much less than the maximum width of the first coxa. Mesosoma except for propodeal declivity without spongiform tissue. Propodeal declivity equipped with a broad and conspicuous lamella; propodeal tooth very feeble and not sclerotized; posterior margin of the lamella convex, and immediately under the propodeal tooth of the margin sometimes slightly concave. Ventral margin of petiole in lateral view with longitudinal spongiform tissue. With petiole in lateral view, anteriormost point of lateral spongiform lobe nearly reaches level of anterior face of node.

Dorsal and lateral surfaces of pronotum entirely reticulate-punctate, sometimes with a small patch above the fore coxa. Metapleuron and side of propodeum entirely smooth. Limbus distinct. Abdominal tergite IV longitudinally sculptured at the basal portion, but not entirely covered.

With head in full-face view, a pair of distinct long flagellate hairs present on apicoscrobe; posterior to the apicoscrobal hairs with laterally projecting distally plumose filiform hairs; anterior to the apicoscrobal hairs without laterally projecting hair. With head in lateral view, dorsal surface from level of eye to preoccipital margin with erect to reclinate ground-pilosity; hairs on preoccipital margin distinctly differentiated from those on level of eye; from highest point of vertex to preoccipital margin with the anteriorly directed ground-pilosity, which is very feebly curved basely so that each hair is elevated and inclined upward away from the cephalic outline. A pair of long, flagelliform hairs present on the pronotal humeri and mesonotum. Dorsum of hind femur without short erect hairs, but with two or three (usually two) long erect flagellate hairs. Dorsal surface of hind basitarsus with one freely projecting flagellate hair. The whole of the dorsal surface of abdominal tergite IV with long filiform hairs. Basal portion of abdominal sternite IV covered with matted hair-like tissue.

Body almost unicolorous, reddish brown to yellowish brown.

Queen
HL 0.65 - 0.67, HW 0.47 - 0.50 CI 72.4 - 76.1, ML 0.29 - 0.33, MI 45.3 - 48.8, SL 0.36 - 0.38, SI 74.0 - 78.0, DlO 0.04, DlOI 7.49 - 8.79, EL 0.12 - 0.14, EI 25.7 - 29.1, HD 0.32 - 0.34, PrH 0.21 - 0.25, MsW 0.33 - 0.36, MsWI 66.8 - 75.6, MsH 0.12 - 0.15, MsHI 25.1 - 29.8, DSA 3 L 0.13 - 0.16, DSA 3 W 0.22 - 0.23, DSA 3 I 135.8 - 169.1 (9 measured).

Generally similar to the worker with the usual caste differences. Head thicker than that of queen of Strumigenys lewisi in lateral view. With head in full-face view, the ocelli distinctly developed, situated at posterior 1/4 of the head. Eye relatively large. A distinct, long and spiniform preapical tooth present close to apical teeth. Apical teeth consisting of two spiniform teeth and three small intercalary teeth between them: basal one of the two spiniform teeth longer than another apical one: basal one of the three intercalary teeth distinctly smaller than the apical two. With mesosoma in lateral view, the highest point of the mesoscutum nearly situated on extension line of the mesopleural wing process; mesopleural gland orifice distinct, but its maximum width not reaching maximum width of the procoxa; the pits on the mesepisternum invisible. Metanotum in lateral view slightly convex posteriorly. Propodeal spine developed and sclerotized, and under which the lobe of spongiform tissue distinctly developed. With the spongiform tissue on propodeal declivity in lateral view, its posterior margin concave under the propodeal spine, and the remaining convex posteriorly. With mesoscutum in dorsal view, its anterior margin rounded, both lateral margins weakly constricted at posterior 1/3, lateral corners by the constriction not strongly angular. Transverse furrow on the mesoscutum weakly curved posteriorly. Mesoscutum wide (MsWI more than 63), its width exceeding 3/4 of the head width in frontal view. With petiole in lateral view, the lobe of spongiform tissue strongly developed.

Most of veins on both of the fore and hind wings absent or vestigial. Only costal (C) and radial (R 1) veins and r-rs cross vein clearly present on fore wing. Vestiges of the radial sector (Rs), M + Cu, and cubital (Cu) veins sometimes visible as pigmented lines but not sclerotized. On the hind wing, radial (R) vein present, but not reaching to costal margin; jugal lobe absent.

Head and mesosomal dorsum entirely reticulopunctate. Central part of mesepisternum and most part of propodeum ventral to propodeal spiracle not punctate and smooth. Dorsal margin of petiole reticulate- punctate. Dorsal surface of postpetiole not punctate and smooth. Limbs present on abdominal tergite IV. Abdominal tergite IV longitudinally sculptured at the basal portion, but sculpture not extended to posterior half.

Pairs of hairs on the pronotal humeri long and flagellate. Mesonotal dorsum with erect, and straight or flagellate hairs. Dorsum of hind femur without short erect hairs, but with two or three (usually two) long erect flagellate hairs. Dorsal surface of abdominal tergite IV with long filiform hairs. Hair-like tissue on the basal portion of abdominal sternite IV dense. Fore and hind wings densely hairy.

Body almost unicolorous, reddish brown to yellowish brown. Outer margins of ocelli distinctly bordered by brown to black pigment on inside portions among the three.

Male
HL 0.46 - 0.48, HW 0.42 - 0.44, CI 87.3 - 95.6, SL 0.09 - 0.11, SI 21.9 - 24.9, DlO 0.05 - 0.07, EL 0.19 - 0.20, HD 0.34 - 0.36, PrH 0.23 - 0.26, MsW 0.40 - 0.43, MsWI 90.8 - 103.2, MsH 0.13 - 0.15, MsHI 30.7 - 35.4 (6 measured).

With head in full-face view, portion posterior to the eyes subglobose; anterior to the eyes distinctly narrowed anteriorly. Ocelli distinct; the median ocellus situated about posterior 1 / 4 of the head length, the lateral ocelli not reaching to the posterior border of the head. Eyes distinctly developed and prominent, occupying central 1 / 3 of lateral margin of the head in full-face view. Eye in lateral view broadened ventrally, and its outer margin expanded anteroventrally and flattened posteriorly. Anterior tentorial pits indistinct. Anterior margin of the clypeus in full-face view slightly convex, but nearly straight. Frontal carinae undeveloped and antennal insertions exposed. Antennae long and filiform, consisting 13 segments. Scape short and broad. Pedicel short and broadened apically. With mandible in full-face view, its apical portion abruptly curved and narrowed; the basal lamella recognizable but very weakly projected; apical to the lamella edentate. Mandible in lateral view very narrowly subtriangular. With labrum in full-face view; its apical portion distinctly extended laterally; the distal lobes entirely reduced, and apical margin of the labrum concave toward the midpoint. Palp formula 1, 1 (1 observed on SEM). Mesosoma in lateral view shorter and higher than that of the queen. Mesoscutum distinctly developed and strongly raised dorsally in lateral view. Mesoscutellum developed and extended posteriorly. With the mesonotum in dorsal view, the median notal suture weakly impressed but mostly invisible; the notauli weakly impressed; the parapsidal furrows distinctly impressed and continued to the distinct transscutal suture, so that the axillae distinctly divided; anterior margin of the scuto-scutellar suture distinctly sculptured longitudinally. With mesopleuron in lateral view, its anteroventral margin distinctly more expanded than that of queen. Metanotum in lateral view slightly extended posteriorly. With the propodeum in lateral view, a distinct spiracle situated at the midheight; the posterior margin with distinct corner, but the spine or dent reduced; the lamella absent ventral to the propodeal corner, even if its ventral portion with a carina along the propodeal declivity. With the petiole in lateral view, the node more gently raised than that of worker and queen; the lateral spongiform lobe entirely reduced; the longitudinal spongiform tissue feebly present. Ventral surface of abdominal sternite III in lateral view usually with a distinct process and a weak lamella, but rarely the process reduced. Abdominal segment IV in lateral view thicker than that of worker and queen, the ventral expansion more gentle.

With genitalia in ventral view, the basal ring broader than long; lateral margins of the parameral plate weakly concave; the cuspis of volsella distinctly shorter than the digitus. With genitalia in lateral view, an anteriorly-directed process, such as the barb, present at apical 1/4 of its ventral margin; the digitus of volsella gradually curved ventrally and not broadened at the corner.

Fore and hind wings similar to those of queen.

Head, pronotum, mesonotum, and metanotum entirely reticulate-punctate. Central part of mesepisternum and most part of propodeum ventral to propodeal spiracle not punctate and smooth. Dorsal margin of petiole reticulate-punctate. Dorsal surface of postpetiole not punctate and smooth. Limbus absent.

Two pairs of standing filiform hairs present on the vertex. With head in lateral view, long and frontally projecting hairs absent anterior to median ocellus. Mesonotum with long, erect, and filiform to flagellar hairs. Dorsal surface of the petiole, abdominal tergite III and IV with sparse filiform hairs.

Body almost unicolorous, blackish brown to reddish brown, legs same or lighter.

Type Material
Holotype worker, Japan: Gozenyama, Ibaraki Pref., 11. viii. 2002, M. Yoshimura leg., specimen code [649 - 1]. ( Type No. [OMNH TI 196], Osaka Museum of Natural History ). Paratypes. colony code [649] in Yoshimura collection: 1 alate queen, 4 dealate queens, 37 workers, 2 males, same data as holotype.

Etymology
The species is named from the Japanese “ Kumadori ”, a traditional make-up for the Kabuki actor.

References based on Global Ant Biodiversity Informatics

 * Harada Y. S. Koto, N. Kawaguchi, K. Sato, T. Setoguchi, R. Muranaga, H. Yamashita, A. Yo, and S. Yamane. 2012. Ants of Jusso, Isa City, Kagoshima Prefecture, southwestern Japan. Bull. biogeogr. Soc. Japan 67: 143-152.
 * Harada Y., K. Nishikubo, K. Matsumoto, M. Matsuda, Y. Inazawa, Y. Ozono, S. Koto, N. Kawaguchi, and S. Yamane. 2011. Ant fauna of Japanese beech (Fagus crenata) forests in southwestern Japan. Bull. Biogeogr. Soc. Japan 66: 115-127.
 * Kida Y., and S. Hori. 2013. Ants from Okushiri-Island, Hokkaido, Japan. Ari 35: 1-5.
 * Masuko, K. 2010. Nest density and distribution of subterranean ants in an evergreen broadleaf forest in Japan with special reference to Amblyopone silvestrii. Entomological Science 13:193
 * Sato T., N. Tsurusaki, K. Hamaguchi, and K. Kinomura. 2010. Ant fauna of Tottori prefecture, Honshu, Japan. Bulletin of the Tottori Prefectural Museum 47: 27-44.
 * Terayama M., S. Kubota, and K. Eguchi. 2014. Encyclopedia of Japanese ants. Asakura Shoten: Tokyo, 278 pp.
 * Yoshimura M., and K. Onoyama. 2007. A new sibling species of the genus Strumigenys, with a redefinition of S. lewisi Cameron. Memoirs of the American Entomological Institute 80:664-690.