Tetramorium lanuginosum Mayr, 1870

Yamane 1, Seiki, Hosoishi 2, Shingo & Ito 3, Fuminori, 2022, Japanese Tetramorium queens: identification key and species diagnoses (Hymenoptera, Formicidae, Myrmicinae), ZooKeys 1084, pp. 43-64 : 43

Tetramorium lanuginosum Mayr, 1870

Figs 1b, h , 2c , 4c , 5c

Queen diagnosis.

Measurements (n = 5): TBL 2.5-3 (2.7), HL 0.69-0.73 (0.71), HW 0.69-0.73 (0.7), SL 0.45-0.5 (0.46), EL 0.2-0.21 (0.2), EW 0.16-0.18 (0.17), PtW 0.27-0.28 (0.28), PptW 0.29-0.3 (0.29), CI 95.9-101.4 (98.6), SI 61.6-72.5 (65.9), ELI 27.4-30.4 (28.7). Body yellowish-brown, with gaster much darker. Head almost as long as broad. Frons medially with longitudinal rugae; other portions of head puncto-reticulate. Clypeus irregularly and superficially sculptured and shiny, with median carina. Eye large; distance between anterior eye margin and mandibular base much shorter than half eye length. Pronotum, mesonotum, lateral mesosoma, except for lower portion of mesopleuron and petiolar and postpetiole nodes puncto-reticulate except for lower portion of mesopleuron rather shiny (mesoscutum may have rather distinct longitudinal rugae). Peduncle of petiole smooth and shiny; dorsal face of petiole not defined, smoothly continuous to declivity; subpetiolar process almost missing. Gastral tergite 1 without longitudinal carinae at base. Vertex and mesosoma with many bifid and fewer trifid erect hairs; these hairs much fewer on gastral tergites.

Caste difference.

Worker measurements (n = 5): TBL 2.1-2.6 (2.4), HL 0.64-0.68 (0.65), HW 0.6-0.65 (0.62), SL 0.43 (0.43), EL 0.14-0.15 (0.15), EW 0.09-0.11 (0.1), PtW 0.18-0.23 (0.21), PptW 0.23-0.25 (0.24), CI 93.8-98.4 (95.4), SI 66.2-71.7 (69.2), ELI 22.1-23.4 (22.7). Worker consistently smaller than the queen. Head only slightly longer than broad in the worker. In the worker, dorsum of head rather extensively reticulate, with weak longitudinal rugae, and mesosomal dorsum densely reticulate, completely lacking rugae; in the queen, at least some rugae recognised on mesonotum. Lateral face of mesosoma entirely sculptured; in the queen, lower portion of mesopleuron more or less smooth and shiny. Eye smaller, only slightly longer than distance between anterior eye margin and mandibular base; in the queen, eye distinctly longer than the distance. Bifid hairs denser on gastral tergite 1 than in the queen.

Specimens examined.

C. Ryukyus: 11q (2 dealated, 9 winged), Takabaru, Yoro-jima, Amami Islands, 2.vii.2015, rotting branch on ground, Sk. Yamane leg. (JP15-SKY-27); 4q (3 winged, 1 dealate), Suehiro Park, Shuri, Okinawa-jima, Okinawa Is., emerged from colony (FI19-25) collected on 11.iii.2019 from soil and reared in lab. S. Ryukyus: 5q (winged), Ishigaki-jima, Yaeyama Is., emerged from colony (FI19-15) collected on 7.ii.2019 from under stone in forest and reared in lab; 1q (dealate), Komi, Iriomote-jima, Yaeyama Is., 16.v.1979, K. Ogata leg. (Figs 2c , 4c , 5c ); 7q (4 winged, 3 dealate), Inbi-dake, Yonaguni-jima, Yaeyama Is., emerged from colony (FI15-96) collected on 7.xi.2015 from decayed wood in forest and reared in lab.

Distribution

in Japan. Nansei Islands. The northern limit lies in Kuchinoerabu-jima and Tanega-shima of the Ôsumi Islands ( Yamane and Fukumoto 2017).

Remarks.

Tetramorium lanuginosum belongs to the T. obesa species group of the former ' Triglyphothrix Forel, 1890' ( Bolton 1976). This group is characterised by the mixture of simple and bifid hairs on the body, with fewer or no trifid hairs. Tetramorium lanuginosum queens have many bifid hairs on the head and mesosoma (very few on gastral tergite 1), but trifid hairs are absent on the gaster and fewer on head and mesosoma. This species is easily distinguished in both the worker and queen by the presence of bifid and trifid hairs on the body, erect hairs on the antennal scape and mid- and hind-tibiae and the petiole without distinction of the dorsum from posterior declivity.

Figures

Figure 1. Some important characters used in the key to species a-e petiole in profile view a T. pacificum b T. lanuginosum c T. bicarinatum d T. smithi e T. tsushimae f-h anterior half of first gastral tergite f T. bicarinatum g T. simillimum h T. lanuginosum i-k antennal scape showing pilosity on its anterior margin l-n left hindtibia i, l T. cf. kraepelini j, m T. nipponense k, n T. simillimum o, p configuration of ocelli o T. tanakai p T. cf. kraepelini.

Figure 2. Japanese Tetramorium queens: habitus in profile view a T. bicarinatum (Nagashima, Kagoshima-ken, Kyushu) b T. cf. kraepelini (Itoman, Okinawa-jima, Okinawa-ken) c T. lanuginosum (Komi, Iriomote-jima, Okinawa-ken) d T. nipponense (Umi-jinja, Shikano-shima, Fukuoka-shi) e T. pacificum (Upper Thompson Nature Park, Singapore) f T. simillimum (Yoron-jima, Amami Is., Kagoshima-ken). (Same specimens were used for ' head in full-face view' and ' habitus in dorsal view').

Figure 4. Japanese Tetramorium queens: head in full-face view a T. bicarinatum b T. cf. kraepelini c T. lanuginosum d T. nipponense e T. pacificum f T. simillimum g T. smithi h T. tanakai i T. tsushimae.

Figure 5. Japanese Tetramorium queens: habitus in dorsal view a T. bicarinatum b T. cf. kraepelini c T. lanuginosum d T. nipponense e T. pacificum f T. simillimum.