Tetraponera inermis

Nests are located in rotten sticks on the ground, and are small in size. At the type locality I found one dealate queen gleaning the surfaces of leaves, walking rapidly and raising her gaster in the air. She then returned to her nest-a cavity in a small soft dead twig on the ground-which proved to contain eggs, larvae and worker pupae. Thus, this species exhibits non-claustral colony-founding, a trait presumably shared with other members of the T. grandidieri group. The gaster-raising behavior was observed in foraging workers of T. inermis but not those of the other two species with which T. inermis is sympatric: T. grandidieri and Tetraponera merita. Camponotus reaumuri (related to Camponotus putatus) is a possible mimic of T. inermis. (Ward 2009)

Identification
Ward (2009) - The worker of this species can be recognized by the absence of a tooth on the basal margin of the mandible; the more or less concolorous reddish-brown body (the upper half of propodeum is often a richer dark red, and the metasoma is paler); and the lack of a protruding metanotal spiracle when the mesosoma is viewed in profile. In addition, the head tends to be broader than that of Tetraponera grandidieri and Tetraponera hespera (CI 0.88-0.97, versus 0.77-0.88 in T. grandidieri and 0.78-0.90 in T. hespera). From T. hespera it can also be distinguished by the ratio of metatibial length to head width (LHT /HW 1.02-1.09 in T. inermis, and 1.10-1.22 in T. hespera).

Distribution
T. inermis occurs in eastern Madagascar from Montagne d' Anjanaharibe to the vicinity of Tolagnaro (Fort Dauphin). Collections all come from rainforest, at elevations ranging from 30 m to 1040 m. (Ward 2009)

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  inermis. Tetraponera inermis Ward, 2009: 297, figs. 5, 15, 16, 25 (w.q.m.) MADAGASCAR.

In the Forel collection (MHNG, Geneva) there is a problematic worker from “Nosibe, village de l'Imerina” [ = Anosibe an' Ala at 19°26'S 48cl3'E] (leg. Sikora). This worker is large (HW 1.49, LHT 1.79) and unicolored, with an elongate head (CI 0.78), yet the metanotal spiracles are not protruding in lateral view. This individual combines features of T. inermis and T. grandidieri (unicolored form). At the moment I am unable to identify it with certainty.

Worker
n = 11. HW 1.02-1.27, HL 1.05-1.42, LHT 1.05-1.38, CI 0.88-0.97, FCI 0.12-0.15, REL 0.31-0.36, REL2 0.35-0.39, SI 0.72-0.76, FI 0.29-0.31, PLI 0.50-0.55, PWI 0.43-0.53.

Similar to Tetraponera grandidieri (q.v.). Basal margin of mandible lacking tooth; anterior clypeal margin broadly convex and crenulate, directed forward; head relatively broad (CI 0.88-0.97); metanotal spiracle not visible in lateral view of mesosoma, subtended laterally and anterolaterally by a pair of concavities that are separated by a transverse carina; dorsal face of propodeum broadly convex in posterior view; standing pilosity and appressed pubescence generally sparse; integument mostly sublucid, with fine coriarious/puncticulate sculpture; head and mesosoma reddish-brown, upper part of propodeum often a darker red than rest of mesosoma; metasoma and appendages paler.

Type Material
Holotype worker. MADAGASCAR Toamasina: 1 km SSW Andasibe (=Perinet), 920 m, 18°56'S 48°25'E, 16.xi.1990, ex rotten stick on ground, rainforest, P. S. Ward#10941 (CASENT0012862).

Paratypes. Series of workers and queens, same locality as holotype, 16.xi.1990 and 12.xii.1990 (P. S. Ward#10940, 19041, 11143) (, CASC,, , , ).

Identification Clarifications
In earlier identifications of museum material I assigned the code name Tetraponera psw81 to this species. During initial examination of Tetraponera hirsuta I misidentified it as T. inermis, using the code name Tetraponera psw81. This is the basis for the record of “Tetraponera psw081” from Manongarivo (Fisher 2002: 318). In fact, T. inermis is not known from that region.