Stenamma nipponense
Stenamma owstoni

Key to Species

Worker Ants




Hymenoptera On-Line








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Japanese Name


Original Reference

Westwood, J.O. (1839) An Introduction to the Modern Classification of Insects; founded on the natural habits and corresponding organisation of the different families 2 (part 11): 193-224. London.


Total length of workers around 2 - 4 mm. Eyes small, shorter than the length of 2nd antennal segment in Japanese species. Median portion of clypeus raised, and with paired longitudinal carinae. Antennae 12-segmented; apical 4 segments sometimes forming an obscure club, or there is no segmentally defined club; scape reaching, or slightly exceeding, posterior margin of head. Posterior margin of head more or less flat, with a low occipital carina. Promesonotum raised. Metanotal groove distinct. Propodeal spines small. Petiole with an elongate peduncle and low node; subpetiolar process absent.


Workers of this genus are similar to those of Aphaenogaster and to minor workers of Pheidole. They can be distinguished from the former by their short antennal scapes and paired longitudinal clypeal striae, and from the latter by the lack of a 3-segmented antennal club. Stenamma comprises about 30 species, most of which are distributed in the Holarctic region. Colony density can be high in Canadian maple or Quercus forests (Francoeur, 1965, 1966). The number of workers in colonies is low - several tens of individuals were recorded in S. diecki by Francoeur (1965). Two species are known from Japan. They were revised by Yasumatsu & Murakami (1960). Arnoldi (1975) described S. kuriense from Kunashiri I. in the Kuril Islands, but its identity is not known to us, and we have not included it in the Japanese ant fauna.


  • Francoeur, A. (1965). Ecologie des populations de fourmis dans un bois de chenes rouges et d' erables rouges. . Naturaliste Can., 92, 263-276.
  • Francoeur, A. (1966). Le genre "Stenamma" Westwood au Quebec (Hymenoptera, Formicidae). Ann. Soc. Ent. Quebec, 11, 115-119.
  • Yasumatsu, K. & Y. Murakami (1960). A revision of the genus Stenamma of Japan (Hym., Formicidae, Myrmicinae). . Esakia, (1), 27-31.
  • Arnoldi, K. V. (1975). Revision der Stenamma-Arten (Hymenoptera, Formicidae) aus der UdSSR. Zool. Zhur., 54, 1819-1829.


Original text by Kazuo Ogata and Keiichi Onoyama. English translation by Kazuo Ogata, edited by Robert W. Taylor.