Aptinoma antongil

Specimens have been collected from canopy habitat on the Masoala Peninsula and on low vegetation near the summit of Montagne d'Anjanaharibe (1100 m) just north of Maroansetra. Like Aptinoma mangabe, this species is arboreal. However, it may not nest in dead twigs as does A. mangabe. Collections suggest that the species nests under canopy litter and moss. The collections in Masoala were made by exploring the canopy using ropes. A. antongil workers were found foraging under moss and litter at the junction of branches. (Fisher 2009)

Identification

 * In profile, metanotal groove distinct and set in shallow V-shaped impression. Propodeal dorsum more or less convex, meeting steeply sloped declivity in blunt, narrowly rounded curve. In dorsal view, lateral margin of pronotum evenly convex, without blunt angle at widest point. Body light to dark brown . . . . Aptinoma antongil


 * In profile, metanotal groove not set in a V-shaped impression. Propodeum in absolute profile without differentiated dorsal and declivitous surfaces, forming single evenly rounded surface. In dorsal view, lateral margin of pronotum with blunt angle at widest point. Body yellow to orange . . . . . Aptinoma mangabe

A. antongil can be separated from A. mangabe by color and shape of propodeum and metanotal groove as outlined in the key above. Minor workers of A. antongil are easily distinguished from minor workers of A. mangabe by length of scape. The scape surpasses the posterior margin of the head in minor workers in A. mangabe while in A. antongil it does not reach the margin. (Fisher 2009)

Distribution
The distribution is limited to forests around Antongil Bay, Madagascar.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Castes
Known only from the worker caste.

Major workers are variable in size and are distinguished from the minor workers by shorter scapes relative to head width (SI 63–73). Since only two minor workers were collected, further samples are needed to evaluate if there is a continuum of worker sizes from minors to the larger majors. (Fisher 2009)

Nomenclature

 *  antongil. Aptinoma antongil Fisher, 2009: 40, figs. 1, 2 (w.) MADAGASCAR.

Worker
Major measurements: maximum and minimum based on all specimens, n=10: HL 0.47–0.63, HW 0.48–0.63, CI 93–102, ED 0.10–0.13, SL 0.34–0.40, SI 63–73, WL 0.50–0.70, FL 0.39–0.49, PW 0.29–0.39.

Minor measurements: maximum and minimum based on all specimens, n=2: HL 0.40–0.42, HW 0.39, CI 94–98, ED 0.09, SL 0.30–0.32 , SI 77–80, WL 0.46, FL 0.34, PW 0.22–0.26.

With characters described in the genus diagnosis for major and minor workers: Anterior clypeal margin without a distinct shallow impression; medial clypeal margin with two or more pairs of setae directed anteriorly; additional pair of setae, slightly anterior of clypeal margin, directed anterodorsally. Scape not surpassing posterior margin of the head in full-face view in both major and minor. In dorsal view, lateral margin of pronotum evenly convex, without blunt angle at widest point. Metanotal groove in profile distinct and impressed. Dorsum of propodeum more or less convex, meeting the steeply sloped declivity in a blunt, narrowly rounded curve. In profile, propodeal spiracle along margin of declivitous face. Body light to dark brown.

Type Material
Holotype: major worker, Madagascar, Province Toamasina, Parc National de Masoala, 39.4 km 150° SSE Maroantsetra, 15.71°S, 49.97°E, 200m, 1 December 2001, under canopy moss and leaf litter, rainforest (coll. B.L.Fisher & H.J.Ratsirarson) collection code: BLF04719, pin code: CASENT0418269. Paratypes: 5 workers with same data as holotype but pins coded CASENT0418267, CASENT0418268, CASENT0418270 (, CASC, MBCC, ).