Erromyrma latinodis

Apart from an excellent series from the Province Fianarantsoa and a small number from Province Antsiranana (MCZ) from tropical and lowland rainforest, I have seen no other Malagasy material pertaining to this tramp species. Malagasy specimens have been collected on low vegetation and on the ground. (Heterick 2006)

Identification
Heterick (2006) - Malagasy region: The sole member of the M. latinode group. Appearance somewhat suggestive of taxa from the Australasian Monomorium rubriceps species group. However, none of the latter has a PF of 3,3, and this count may represent an ancestral plesiomorphy, if indeed the ant is a member of that group. Certainly, the species has no close connections with the remaining African and Malagasy Monomorium fauna. The type specimens for the nominal taxa currently associated with M. latinode (i.e., ‘M. latinode’, ‘M. latinode bruneum’ and ‘M. voeltzkowi’) show variation in color and size, and the lectotype of M. latinode also exhibits some differences in the appearance of the head capsule.

Distribution based on Regional Taxon Lists
Afrotropical Region: Comoros, Mozambique, Saint Helena, United Republic of Tanzania. Australasian Region: New Zealand. Indo-Australian Region: Borneo, Indonesia, Malaysia. Malagasy Region: Madagascar, Mayotte. Oriental Region: Bangladesh, India, Sri Lanka, Thailand. Palaearctic Region: China, Japan.

Biology
In Oman, a nest series was found under a pomegranate tree. Several workers were collected from under a rock where the soil was dry and loose and in an area in cultivated rose plantations. Individuals were also found among leaf litter where soil was dry. (Sharaf et al 2018)

Nomenclature

 *  latinodis. Monomorium latinode Mayr, 1872: 152 (w.) BORNEO.
 * Imai, Baroni Urbani, et al. 1984: 8 (k.).
 * Senior synonym of bruneum, voeltzkowi: Bolton, 1987: 429.
 * Combination in Erromryma: Fisher & Bolton, 2016: 274.
 * See also: Heterick, 2006: 108.
 * bruneum. Monomorium latinode var. bruneum Emery, 1893f: 243 (w.) SRI LANKA.
 * Junior synonym of latinode: Bolton, 1987: 429.
 * voeltzkowi. Monomorium voeltzkowi Forel, 1907g: 78 (w.) TANZANIA.
 * Junior synonym of latinode: Bolton, 1987: 429.

Worker
Heterick (2006) - Lectotype (M. latinode): HML 2.02 HL 0.72 HW 0.59 CeI 81 SL 0.60 SI 103 PW 0.42. Lectotype (Monomorium latinode bruneum): HML 2.03 HL 0.73 HW 0.59 CeI 81 SL 0.56 SI 95 PW 0.46. Lectotype (Monomorium voeltzkowi): HML 1.66 HL 0.60 HW 0.46 CeI 77 SL 0.46 SI 100 PW 0.36. (non-types): HML 1.83–2.29 HL 0.65–0.83 HW 0.52–0.73 CeI 79–88 SL 0.50–0.62 SI 85–98 PW 0.38–0.49 (n=20).

HEAD: Head oval; vertex weakly convex; 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 posteriad of 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 weakly to strongly defined; anteromedian clypeal margin straight, or, emarginate, clypeal carinae terminating in blunt angles; paraclypeal setae moderately long and fine, curved; posteromedian clypeal margin extending slightly beyond level of posterior margin of antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes straight, parallel. Psammophore absent. Palp formula 3,3. Mandibular teeth five; mandibles triangular and smooth (except for piliferous pits); masticatory margin of mandibles approximately vertical or weakly oblique; basal tooth smaller than t4 (five teeth present).

MESOSOMA: Promesonotum shining and smooth on dorsum, entire lower mesopleuron distinctly striolate; (viewed in profile) anterior promesonotum smoothly rounded, thereafter more-or-less flattened, promesonotum on same plane as propodeum; promesonotal setae greater than twelve; standing promesonotal setae consisting of well-spaced, incurved, erect and semi-erect setae only; appressed promesonotal setulae very sparse or absent. Metanotal groove vestigial. Propodeum uniformly finely striolate; propodeal dorsum flat throughout most of its length; propodeum smoothly rounded or with indistinct angle; standing propodeal setae numerous, wholly or mainly erect or suberect, without conspicuous paired setae evident; 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 blunt-angled flanges.

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 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 absent; 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; postpetiolar sternite depressed near its junction with gaster, and sloping anteriad at angle of 45–60 to form large conspicuous lip at its anterior end.

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

GENERAL CHARACTERS: Color head, mesosoma and appendages brownish-yellow, gaster brown. Worker caste monophasically allometric, i.e., with variable size, but not morphology among workers from same nest.

Type Material
Heterick (2006) - Lectotype: worker, Borneo Sarawak (Malaysia), G. Doria. A single carded worker labeled syntype is here designated lectotype to fix the name for opulations of M. latinode, which has a more convex outline to the vertex than M. latinode bruneum or M. voeltzkowi. Other syntype specimens may still exist (seen by Bolton in 1987), and these should be treated as paralectotypes.