Malagidris belti

M. belti is a ground-nesting species of montane rainforest, where it has been recorded as nesting in moss. Workers have also been retrieved from leaf litter, from beating low vegetation, and from a Malaise trap, which indicates that although this species is basically a ground nester and forager, belti also ascends vegetation.

Identification
Bolton and Fisher (2014) - Within the genus, the worker of belti is quickly diagnosed by its relatively broad head (CI 81–84) and short scapes (SI 97–108), their relative dimensions obviously different from all the other species, which have narrower heads (CI < 75) and more attenuated scapes (SI > 140). In addition, the ventral surface of the petiole has a median longitudinal cuticular crest behind the subpetiolar process; the crest is low, but usually obvious. Only Malagidris dulcis has the metafemur as deep as belti (MfL/MfH 4.60–5.50 in dulcis, 4.62–5.22 in belti), but as well as the narrower head and longer scapes of dulcis (CI 68–74, SI 145–160), the side of the head behind the eye has 4–5 projecting setae (as opposed to 0–1 in belti).


 * Key to Eutetramorium group genera

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  belti. Aphaenogaster belti Forel, 1895c: 248 (w.) MADAGASCAR. Combination in Brunella: Forel, 1917: 234; in Atopula: Emery, 1915d: 68; in Aphaenogaster: Bolton, 1982: 341 (see also p. 364); in Malagidris: Bolton & Fisher, 2014: 21.

Description
Bolton and Fisher (2014):

Worker
TL 4.9–5.4, HL 1.02–1.20, HW 0.83–0.99, CI 81–84, SL 0.90–0.97, SI 97–108, PW 0.60–0.69, WL 1.38–1.56 (10 measured).

Mandible usually with 8 teeth and denticles in total, less commonly with 7 or 9; with fine longitudinal costulae basally, but costulae becoming superficial and fading out towards the masticatory margin. Median portion of clypeus slopes evenly to a narrow anterior cuticular apron; median clypeal seta arises from just above midpoint of anterior margin. Median portion of clypeus with a number of weak longitudinal rugulae. Scapes of moderate length (SI < 110), with fine decumbent to appressed pubescence but lacking standing setae; when laid straight back in full-face view the apex of the scape reaches, or just exceeds, the posterior margin. Club segments of funiculus longer than broad, but not remarkably attenuated. EL 0.21–0.26 (EL/HW 0.25–0.27), with 11–12 ommatidia in the longest row. With head in full-face view the sides behind the eyes shallowly convex, rounding broadly and evenly into the posterior margin, the latter more or less transverse to shallowly convex medially. Dorsum of head longitudinally rugose, the rugae strongest medially, weaker and less regular dorsolaterally, and with a few weak anasomoses, especially posteriorly; spaces between the rugae reticulate-punctulate. Ventral surface of head longitudinally costulate to rugulose, those closest to the ventral midline converging anteriorly. Dorsum of mesosoma reticulate-rugose; punctulate ground sculpture between the rugulae much less conspicuous than on the head, effaced in places. In dorsal view pronotum broadest behind the angulate humeri. Propodeal spines in dorsal view distinctly separated basally, in profile short (0.16–0.23). Propodeal declivity unsculptured. Side of mesosoma reticulate-rugose on pronotum and propodeum, but longitudinally rugose on mesopleuron. Metafemur relatively short, MfL 1.12–1.28 (MfL/HW 1.25–1.35), quite deep in posterior view (MfL/MfH 4.62–5.22). Peduncle of petiole in profile slightly longer than the node and with a small, dentiform anteroventral process. Subpetiolar process followed by a low cuticular crest along the mid-ventral surface of the peduncle, that extends back beyond the spiracle. Petiole node in profile narrowly rounded apically. In posterior view the sides of the petiole node weakly convergent in their dorsal halves, and merging into an evenly rounded dorsal outline. Petiole node with superficial remnants of punctulate sculpture. Postpetiole in profile convex dorsally, 1.21–1.37 times longer than high; in dorsal view postpetiole slightly longer than broad, maximum width 0.36–0.43; maximum dorsal width of postpetiole (0.36–0.43) slightly greater than its height. Dorsum of postpetiole node superficially reticulate-punctulate and sometimes with a few vestiges of minute rugulae; sculpture strongest posteriorly. Extreme base of first gastral tergite with short, inconspicuous basigastral costulae; remainder of tergite unsculptured except for setal pits.

Pilosity: with head in full-face view the side in front of the eye with 0–1 projecting setae, behind eye with 0–1 setae; with head in profile the dorsum behind the highest point with 3–5 pairs of setae (sometimes 3–5 short transverse rows of 4 setae) that are inclined anteriorly, dorsum closest to the posterior margin with a transverse row of 4–6 setae; pronotal dorsum with 2–4 setae anteriorly and 1 pair (rarely 2 pairs) very close to the junction with the mesonotum; mesonotum with 3 pairs and usually also with a short pair at the metanotal groove; propodeal dorsum lacks setae; ventral surface of metafemur usually without setae but sometimes with one present, close to the trochanter; petiole node with a pair of setae on its posterior face, and sometimes also with a posterobasal pair; postpetiole with 1–2 pairs dorsally and with a transverse row of 4 posteriorly; gaster with numerous short, simple setae. Full adult colour orange-brown to reddish.

Queen
(Gyne). Alate, with conspicuous ocelli and a broad transverse mesopleural sulcus. TL 6.0–6.2, HL 1.16–1.25, HW 1.00–1.08, CI 86, SL 0.98, SI 91–98, PW 0.75–0.82, WL 1.74–1.76, MfL 1.26–1.35, MfL/HW 1.25–1.26, MfL/MfH 4.50–5.25. EL 0.29–0.30 (EL/HW 0.28–0.29) (2 measured). Mesoscutum width 0.80–0.83, length 0.76–0.84. Postpetiole length 0.50–0.54, width 0.48–0.50, height 0.44–0.46. Most dimensions are slightly greater than the worker ranges, but the scape is relatively slightly shorter. Cephalic pilosity as worker but pronotum with 1 lateral pair and a transverse row of 4 posteriorly, just in front of the anterior margin of the mesoscutum; mesoscutum with about 16–18 setae, mesoscutellum with 2–4, metanotum with 2; setae absent from propodeum.

Male
Mandible with 6–8 sharp teeth. CI 78–82, SI 58–59, MfL ca 1.20 (2 measured). First funicular segment of antenna 0.42–0.50 × the length of the second segment. EL/HW 0.58–0.61. With head in profile the dorsal outline behind the posterior ocelli descends vertically to the occipital carina, which is borne on a posteriorly projecting prominence or lobe. With mesosoma in dorsal view the arc of the pronotum is concealed medially by the anterior bulge of the mesoscutum. Notauli with anterior portions discernible, but shallow and almost effaced. Peduncle of petiole with spiracles not borne on tubercles, in dorsal view the maximum width of the petiole is across the node. Postpetiole in dorsal view only 1.24–1.29 × longer than broad.

References based on Global Ant Biodiversity Informatics

 * Bolton B., and B. L. Fisher. 2014. The Madagascan endemic myrmicine ants related to Eutetramorium (Hymenoptera: Formicidae): taxonomy of the genera Eutetramorium Emery, Malagidris nom. n., Myrmisaraka gen. n., Royidris gen. n., and Vitsika gen. n. Zootaxa 3791(1): 1-99.
 * Fisher B. L. 1997. Biogeography and ecology of the ant fauna of Madagascar (Hymenoptera: Formicidae). Journal of Natural History 31: 269-302.
 * Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.
 * Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. IX. A synonymic list of the ants of the Malagasy region. Bulletin of the American Museum of Natural History 45: 1005-1055