Tetramorium melanogyna Mann

Bolton, B., 1979, The ant tribe Tetramoriini (Hymenoptera: Formicidae). The genus Tetramorium Mayr in the Malagasy region and in the New World., Bulletin of the British Museum (Natural History) Entomology 38, pp. 129-181 : 173-174

Tetramorium melanogyna Mann sp. rev.

Tetramorium melanogyna Mann, 1919: 345 , fig. 28. Syntype workers, female, Solomon Is.: Ugi, Pawa, 1916 (W. M. Mann) and Three Sisters, Malapaina, 1916 (W. M. Mann) (MCZ, Cambridge; USNM, Washington) [examined]. Tetramorium melanogyna Mann ; Bolton, 1977: 99 [as synonym of T. insolens (F. Smith) ].

A critical reappraisal of the material of melanogyna presently available for study has convinced me that I was mistaken in synonymizing this species with the much more widespread T. insolens , and I hereby reverse that decision, restoring melanogyna to its original status as a good species.

As far as is known melanogyna is restricted to the Solomon Islands and thus it is only specimens from here which may be confused with insolens , which also occurs on these islands. Samples of melanogyna workers will key out at insolens in Bolton (1977), but the two may be distinguished as follows.

insolens

Gaster lighter in shade than head and alitrunk.

Hairs on dorsal (outer) surface of hind tibiae suberect to subdecumbent.

Rugoreticulum on postpetiole dorsum very strong, as well developed as on pronotum.

In a majority of workers the rugose sculpturing of the alitrunk forming a transverse ridge at promesonotal junction.

melanogyna

Gaster darker in shade than head and alitrunk, or at least with an infuscated transverse band.

Hairs on dorsal (outer) surface of hind tibiae decumbent to appressed.

Rugoreticulum on postpetiole dorsum weak, more feebly developed than on pronotum.

Rugose sculpturing of alitrunk not forming a transverse ridge at promesonotal junction.

The queens of the two species are easily distinguished as in insolens the female has the same colouring as the workers, whilst in melanogyna the queen is uniform dark brown. Other names given as synonyms of insolens in Bolton (1977: 99) remain as such.

Correction to key. In the key to Tetramorium of the Oriental and Indo-Australian regions (Bolton, 1977: 72), the second half of couplet 13 should read, ' Dorsum of postpetiole unsculptured. .. ', not ' Dorsum of petiole' as is printed. This brings it in line with the first half of the couplet.