Monomorium platynode

Specimens of M. platynodis have been collected from sifted litter and by hand from a rotten log in tropical dry forest and rainforest.

Identification
Heterick (2006) - A member of the M. flavimembra complex in the M. monomorium species group. The uniformly orange workers are immediately identifiable through their truncated clypeus, three-toothed mandibles and high nodes. The very small males (the queen is not known) resemble those of Monomorium exiguum. The mandible of the male also has three strong teeth, and the entire anterior clypeal margin is straight and well-separated from the basal margin of the mandible. The male node seen in full-face view is bimodal.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Monomorium platynodis is a rather rare species, which, nonetheless, ranges throughout the entire island of Madagascar.

Nomenclature

 *  platynode. Monomorium platynodis Heterick, 2006: 135, figs. 22, 63, 64 (w.m.) MADAGASCAR.

Worker
Holotype: HML 1.15 HL 0.42 HW 0.34 CeI 81 SL 0.29 SI 85 PW 0.24.

HML 1.18–1.33 HL 0.44–0.50 HW 0.36–0.39 CeI 75–84 SL 0.31–0.35 SI 84–91 PW 0.25–0.27 (n=18).

HEAD: Head rectangular; vertex 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 large, eye width 1.5× greater than greatest width of antennal scape; (in full-face view) eyes set above midpoint of head capsule to 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, or, elongate, eye narrowed to point anteriad; Antennal segments 12; antennal club three-segmented. Clypeal carinae indistinct; anteromedian clypeal margin straight; paraclypeal setae moderately long and fine, curved; posteromedian clypeal margin approximately level with antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes sinuate, divergent posteriad. Psammophore absent. Mandibular with three evenly sized teeth; mandibles with sub-parallel inner and outer margins, smooth (except for piliferous pits); masticatory margin of mandibles approximately vertical or weakly oblique; basal tooth approximately same size as t2 (three teeth present).

MESOSOMA: Promesonotum shining and mainly smooth, vestigial striolae, if present, confined to lower anterior mesopleuron; (viewed in profile) promesonotum broadly convex; promesonotal setae seven to greater than twelve; standing promesonotal setae consisting of well-spaced, incurved, erect and semi-erect setae only; appressed promesonotal setulae few, mainly on sides of promesonotum. Metanotal groove strongly impressed, with distinct transverse costulae. Propodeum shining and smooth, with a few weak striolae on metapleuron; propodeal dorsum convex; propodeum always smoothly rounded; standing propodeal setae consisting of two or more prominent pairs anteriad, often with another pair of prominent setae posteriad, and other smaller setae on/around dorsal and declivitous surfaces of propodeum; appressed propodeal setulae very sparse or absent; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum. Vestibule of propodeal spiracle distinct in some specimens. Propodeal lobes present as rounded flanges.

PETIOLE AND POSTPETIOLE: Petiolar spiracle laterodorsal and situated slightly anteriad of petiolar node, or, lateral and situated within anterior sector of petiolar node; node (viewed in profile) cuneate, vertex tapered; appearance of node shining and smooth throughout; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) between 1:1 and 3:4; anteroventral petiolar process absent or vestigial; ventral petiolar lobe present; height ratio of petiole to postpetiole about 4:3; height-length ratio of postpetiole about 3:2; postpetiole shining and smooth; postpetiolar sternite 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 bright yellow-orange. Worker caste monomorphic.

Male
HML 1.31–1.44; HL 0.40–0.41; HW 0.35–0.38; CeI 88–93; SL 0.14–0.17; SI 39–46; PW 0.42–0.44 (n=3).

HEAD: Head width-mesosoma width ratio between 1:1 and 3:4; frons finely micropunctate. Compound eyes protuberant and elliptical; margin of compound eye clearly separated from posterior margin of clypeus. Ocelli not turreted. Ratio of length of first funicular segment of antenna to second funicular segment about 1:1. Maximum number of mandibular teeth and denticles three.

MESOSOMA: Mesoscutum broadly convex; pronotum and mesoscutum shining, with dorsum of mesoscutum faintly striolate. Parapsidal furrows vestigial or absent; notauli absent. Axillae separated by width of at least one axilla.

WING: Wing veins predominantly depigmented, with distal segments reduced to vestigial lines; vein m–cu absent; vein cu–a absent.

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated within anterior sector of petiolar node. Node (viewed in profile) conical, vertex rounded; appearance of node shining and smooth; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) about 4:3. Anteroventral petiolar process absent or vestigial. Height ratio of petiole to postpetiole between 4:3 and 1:1; height–length ratio of postpetiole between 4:3 and 1:1; postpetiole shining and smooth.

GASTER: Pilosity of first gastral tergite consisting of well-spaced, semi-erect setae.

GENERAL CHARACTERS: Color brown.

Type Material
Holotype: worker, Prov. Toamasina, Mont Anjanaharibe, 18.0 km 21 NNE Ambinanitelo 470 m 15º11′3″S, 49º36′9″E, 8–12.iii.2003 Fisher et al. BLF 8002/sifted litter tropical dry forest/ CASENT 0026538 8002(24). Paratypes: Prov. Toamasina (all specimens with same collection data as holotype): 13 workers ; 13 workers ; 13 males + 13 workers.

Etymology
Greek ‘platys’ (flat) + pl. of masc. ‘nodus’

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