Monomorium flavimembra

Workers have been collected in tropical dry forest as ground foragers, in sifted litter and from colonies in wood (rotted logs and twigs) and root mats.

Identification
Heterick (2006) - A member of the M. flavimembra complex in the M. monomorium species group. Monomorium flavimembra is similar in morphology to Monomorium bifidoclypeatum, but the anteromedian clypeal sector is only weakly carinate, and the petiolar node is higher and less sharply conical. The basal tooth is usually present as a small obtuse angle but may be absent altogether. The rich, russet color of the upper part of the frons and mesosoma contrasts with the bright yellow clypeus, mandibles and appendages in most specimens, but the legs may have a brownish tinge. The four known queens, all dealated, are very small and ergatoid-like. Queens of more regular proportions (for a Monomorium whose workers reach about 2 mm TL) may exist among the unclassifiable CAS Monomorium queen material that cannot be associated with workers.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  flavimembra. Monomorium flavimembra Heterick, 2006: 120, figs. 19, 53, 54 (w.q.) MADAGASCAR.

Worker
Holotype: HML 1.33 HL 0.48 HW 0.43 CeI 89 SL 0.40 SI 94 PW 0.25.

HML 1.12–1.31 HL 0.41–0.50 HW 0.37–0.43 CeI 83–89 SL 0.34–0.42 SI 89–101 PW 0.23–0.27 (n=20).

HEAD: Head oval; vertex planar or weakly concave; frons shining and smooth except for piliferous pits; pilosity of frons a mixture of well-spaced, distinctly longer erect and semi-erect setae interspersed with shorter decumbent setae or setulae. Eye moderate, eye width 1–1.5× greatest width of antennal scape; (in full-face view) eyes set below midpoint of head capsule; (viewed in profile) eyes set around midline of head capsule; eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin. Antennal segments 12; antennal club three-segmented. Clypeal carinae indistinct; anteromedian clypeal margin broadly convex; paraclypeal setae short and thickened, not reaching basal margin of closed mandibles; pos teromedian clypeal margin extending slightly beyond level of posterior margin of antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes sinuate, divergent posteriad. Psammophore absent. Mandibular teeth three, plus minute, basal denticle or angle; mandibles with sub-parallel inner and outer margins, smooth (except for piliferous pits); masticatory margin of mandibles approximately vertical or weakly oblique; basal tooth a small to minute denticle or angle, much smaller than t3 (four teeth present).

MESOSOMA: Promesonotum shining and mainly smooth, vestigial striolae, if present, confined to lower anterior mesopleuron; (viewed in profile) promesonotum broadly convex anteriad, convexity reduced posteriad; promesonotal setae seven to twelve; standing promesonotal setae a mixture of well-spaced, distinctly longer, erect and semi-erect setae which are curved distally and often paired, interspersed with much shorter, incurved, decumbent setae; appressed promesonotal setulae very sparse or absent. Metanotal groove strongly impressed, with distinct transverse costulae. Propodeum shining and smooth, with a few weak striolae on metapleuron; propodeal dorsum flat throughout most of its length; propodeum smoothly rounded or with indistinct angle; standing propodeal setae consisting of one prominent pair anteriad, with other shorter setae very sparse or absent; appressed propodeal setulae very sparse or absent; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum. Vestibule of propodeal spiracle absent or not visible. Propodeal lobes present as blunt-angled flanges.

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated within anterior sector of petiolar node; node (viewed in profile) conical, vertex tapered to conical, 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 about 4:3; height–length ratio of postpetiole between 4:3 and 1:1; postpetiole shining and smooth; postpetiolar sternite not depressed at midpoint, its anterior end an inconspicuous lip or small carina, or without anterior lip or carina, or this structure vestigial.

GASTER: Pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with a few appressed setulae.

GENERAL CHARACTERS: Color light to dark reddish brown, gaster darker brown, appendages yellowish. Worker caste monomorphic.

Queen
HML 1.55–1.57 HL 0.51 HW 0.47–0.49 CeI 92–96 SL 0.43–0.45 SI 88–95 PW 0.34–0.35 (n=4).

HEAD: Head rectangular; vertex weakly concave or planar; frons shining and smooth except for piliferous pits; pilosity of frons a mixture of well-spaced, distinctly longer erect and semi-erect setae interspersed with shorter setae or setulae, which are decumbent or appressed, longer setae thickest on vertex. Eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin; (in full-face view) eyes set at about midpoint of head capsule; (viewed in profile) eyes set posteriad of midline of head capsule.

MESOSOMA: Mesoscutum broadly convex anteriad, convexity reduced posteriad; pronotum, mesoscutum and mesopleuron shining and mainly smooth, vestigial striolae, if present, confined to anterior katepisternum; length–width ratio of mesoscutum and scutellum combined between 2:1 and 3:2; axillae contiguous, or nearly so; standing pronotal/mesoscutal setae consisting of well-spaced, incurved, erect and semi-erect setae only; appressed pronotal, mescoscutal and mesopleural setulae few, mainly on sides of pronotum and mesopleuron; propodeum shining and smooth, with a few distinct striolae on metapleuron; propodeum smoothly rounded or with indistinct angle; propodeal dorsum flat throughout most of its length; standing propodeal setae consisting of up to a dozen or more longer erect and shorter sub-erect setae; appressed propodeal setulae very sparse or absent; propodeal spiracle nearer metanotal groove than declivitous face of propodeum; propodeal lobes present as well-developed, rounded flanges.

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated within anterior sector of petiolar node; node (viewed in profile) conical, vertex tapered; appearance of node shining and weakly striolate posteriad; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) between 4:3 and 1:1; anteroventral petiolar process absent or vestigial; height ratio of petiole to postpetiole between 4:3 and 1:1; height–length ratio of postpetiole between 2:1 and 4:3; postpetiole shining and weakly striolate posteriad; postpetiolar sternite without anterior lip or carina, or this structure vestigial.

WING: Wing not seen (queens dealated).

GASTER: Pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with a few appressed setulae.

GENERAL CHARACTERS: Color foreparts reddish brown, gaster brown, appendages yellow. Brachypterous alates not seen. Ergatoid or worker-female intercastes not seen.

Type Material
Holotype: worker, Prov. Antsiranana, Réserve Spéciale Ambre, 3.5 km 235 SW Sakaramy 325m, 12 29’S, 49 15’E, 26–31.i.2001, Fisher et al. BLF# 2676 /ex rotten log tropical dry forest/ CASENT 0401520. Paratypes: Prov. Antsiranana (three workers and three queens collection code 2676, seven workers collection code 2679, otherwise data as for the holotype): 12 workers ; 1 worker + 12 queens + 12 workers ; 1 worker (CAS) 1 queen + 12 workers + 2 workers.

Etymology
Latin ‘flavus’ (yellow) + pl. of ‘membrum’ (neut. ‘member’)

References based on Global Ant Biodiversity Informatics

 * Goodman S., Y. Anbdou, Y. Andriamiarantsoa, B. L. Fisher, O. Griffiths, B. Keitt, J. J. Rafanomezantsoa, E. Rajoelison, J. C. Rakotonirina, L. Ranaivoarisoa et al. 2017. Results of a biological inventory of the Nosy Ankao island group, Parc National de Loky-Manambato, northeastern Madagascar. Malagasy Nature, Association Vahatra, 2017, 11, 
 * Heterick B. 2006. A Revision of the Malagasy Ants Belonging to Genus Monomorium Mayr, 1855 (Hymenoptera: Formicidae). Proceeding of the California Academy of Sciences (PCAS) 57: 69-202