Monomorium ferodens Heterick

Figs. 27, 77, 100.

Etymology.- Latin "ferox" ("fierce") + "dens"

Material examined.- Holotype: [[worker]], 40 km S Ambalavao, Res. Andringitra, 22°13'S, 46°58E 1275m 15.x.1993 B.L. Fisher #793(8)-13/sifted litter (leaf mold, rotten wood), montane rainforest (CAS). Paratypes: Prov. Fianarantsoa (specimens with same collection data as holotype): 2 [[worker]] (ANIC) 12 [[worker]] (BMNH); 2 [[worker]] (CAS); 12 [[worker]] + 1 [[worker]] (MCZ).

Other material examined: Prov. Fianarantsoa: 38 km S Ambalavao, Res. Andringitra, 23.x.1993 B.L. Fisher (3 5); R. S. Ivohibe, 6.5 km ESE Ivohibe, 24-30.x.1997 BL. Fisher (3 5). Prov. Toliara: 13 km NW Enakara, Res. Andohahela, 30.xi.192 BL. Fisher (5 [[worker]]); P.N. Andohahela, 3.8 km 113 ESE Mahamavo 21-25.i.2002 Fisher et al. (5 [[worker]]).

Worker description.- Head: Head rectangular; vertex planar or weakly concave; frons shining and smooth except for piliferous pits; frons a mixture of incurved, semi-erect setae and slightly shorter decumbent setae. Eye small, eye width less than 1x greatest width of antennal scape; eyes set above midpoint of head capsule; set posteriad of midline of head capsule; more-orless circular to semi-circular. Antennal segments 12; club three-segmented. Clypeal carinae weakly to strongly defined; anteromedian clypeal margin straight; paraclypeal setae moderately long and fine, curved; posteromedian clypeal margin approximately level with antennal fossae. Anterior tentorial pits equidistant from antennal fossae and mandibular insertions. Frontal lobes sinuate, divergent posteriad. Psammophore absent. Palp formula 3,2. Mandibular teeth four; mandibles linear-triangular and smooth (except for piliferous pits); masticatory margin of mandibles strongly oblique; basal tooth distinctly larger than t3 (four teeth present).

Mesosoma: Promesonotum shining and mainly smooth, vestigial striolae, if present, confined to anterior of lower mesopleuron, or, shining and smooth on dorsum, entire lower mesopleuron distinctly striolate; in profile broadly convex; promesonotal setae greater than twelve; standing promesonotal setae consisting of a mixture of incurved, semi-erect setae and slightly shorter decumbent setae; appressed promesonotal setulae few, mainly on sides of promesonotum. Metanotal groove strongly impressed, with distinct transverse costulae. Propodeum shining and smooth, metapleuron with multiple hair-like striolae; propodeal dorsum sloping posteriad, and depressed between raised propodeal angles; angulate, propodeal angle blunt; length ratio of propodeal dorsum to its declivity about 1:1; standing propodeal setae consisting of one prominent pair anteriad, with a few to many erect to decumbent setae on/around dorsal and declivitous faces of propodeum; appressed propodeal setulae very sparse or absent; propodeal spiracle nearer declivitous face of propodeum than metanotal groove; vestibule of propodeal spiracle distinct; propodeal lobes present as rounded flanges.

Petiole and postpetiole: Petiolar spiracle laterodorsal and situated slightly anteriad of petiolar node. Petiolar node, in profile, subcuboidal, vertex rounded; appearance of node shining and smooth throughout; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) between 4:3 and1:1. Anteroventral petiolar process absent or vestigial; ventral petiolar lobe present. Height ratio of petiole to postpetiole between 3:2 and 4:3; height-length ratio of postpetiole between 3:2 and 4:3; postpetiole shining and smooth; postpetiolar sternite not, or, only slightly depressed at midpoint, anterior process prominent.

Gaster: Pilosity of first gastral tergite consisting of a mixture of incurved, semi-erect setae and slightly shorter decumbent setae.

General characters: Color pale, depigmented yellow. Worker caste monomorphic.

Holotype measurements: HML 1.43 HL 0.51 HW 0.44 CeI 86 SL 0.40 SI 91 PW 0.31.

Other worker measurements: HML 1.21-1.57 HL 0.45-0.57 HW 0.37-0.47 CeI 80-87 SL 0.35-0.44 SI 87-97 PW 0.26-0.32 (n=20).

Remarks.- The worker (queens and males are unknown) of this unobtrusive, but interesting species can easily be confused with a small, pale worker of M. hildebrandti . However, it can readily be distinguished by its PF of 3,2 and the enlarged, down-curved basal tooth. In profile, the clypeal protuberance tends to form a blunter angle than is the case with M. hildebrandti , its configuration more closely resembling that found in M. sechellense . The species is comparatively rare, being known from four sites in Fianarantsoa and Toliara Provinces. All have been taken in sifted litter (leaf mold and rotten wood) in rainforest.