Nesomyrmex stramineus

Nesomyrmex stramineus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Crematogastrini
Genus:	Nesomyrmex
Species group:	angulatus
Species:	N. stramineus
Binomial name
	Nesomyrmex stramineus; (Arnold, 1948) Specimen Labels

Mbanyana and Robertson (2008) - Nests in dead wood on trees. Specimens have been collected from savanna woodland and Afromontane forest.

Identification

Hita Garcia et al. (2017) - A member of the angulatus species-group. The following character combination distinguishes N. stramineus from the other species of the group: eyes with 7–9 ommatidia in longest row; in profile mesosomal dorsum with conspicuously impressed metanotal groove; propodeal spines relatively long and thin, several times longer than their basal width; in profile petiolar node high, rectangular nodiform, appearing around twice as high as long; in dorsal view petiolar node laterally denticulate; subpetiolar process without a long cuticular flange running back to the postpetiolar junction; dorsum of propodeum with standing hairs; first gastral tergite with standing hairs evenly distributed throughout.

Nesomyrmex stramineus is very close to Nesomyrmex denticulatus and Nesomyrmex innocens. For more details on its differentiation from them we refer to the species account of N. innocens.

Among the species which have the metanotal groove impressed stramineus is most closely related to Nesomyrmex innocens, the two species sharing the characters of relatively small eyes and having short hairs on the first gastral tergite (as opposed to the first gastral tergite being hairless). In fact, stramineus and innocens form an extremely close species-pair and may eventually prove to be expressions of a single species. For the present the two may be separated as the sculpture in innocens, although punctulate as in stramineus, is much more strongly developed and sharply defined, with traces of rugular sculpture also present at least on the head. Besides this the petiolar tubercles are not as strongly developed in innocens as they are in stramineus, and the propodeal spines are shorter and broader.

Keys including this Species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -26.11666667° to -33.08927°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Afrotropical Region: Eswatini, South Africa (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

stramineus. Limnomyrmex stramineus Arnold, 1948: 223, fig. 10 (w.) SOUTH AFRICA. Combination in Leptothorax: Brown, 1971a: 4; in Nesomyrmex: Bolton, 2003: 272. See also: Bolton, 1982: 332; Mbanyana & Robertson, 2008: 38.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Bolton (1982) - TL 2.8, HL 0.63, HW 0.53, CI 84, SL 0.36, SI 68, PW 0.38, AL 0.68.

Mandibles very delicately shagreened, almost smooth. Median portion of clypeus with anterior margin evenly arcuate-convex, with a very narrow cuticular apron. Median clypeal carina vestigial. Frontal carinae and antennal scrobes absent, the antennal scapes short. Maximum diameter of eye 0.13, about 0.25 x HW and with 7-8 ommatidia in the longest row. Sides of head behind eyes very feebly convex, the sides narrowing in front of the eyes so that the width immediately in front of the eyes is 0.47 and across the clypeus at its widest is 0.38 (compare with HW 0.53). Occipital margin approximately straight and the occipital corners evenly rounded. Alitrunk in profile with promesonotum evenly and shallowly convex, the propodeal dorsum on the same level but shorter and more strongly convex, the two convexities separated by the conspicuously impressed metanotal groove. Propodeal spines narrow and somewhat down curved along their length, longer than their basal widths. Slope of the declivity between the spines and the rounded metapleural lobes straight. In dorsal view the alitrunk with the pronotal shoulders obtusely and bluntly angled, the promesonotum narrowing posteriorly to the metanotal groove. Behind this the propodeum broadening to the level of the spiracle then narrowing again to the bases of the spines; the latter divergent and in the holotype with the right spine slightly longer than the left. Petiole node in dorsal view with a strong lateral tubercle on each side, a pair of smaller tubercles on the posterior margin and a very feeble pair anterodorsally which are almost effaced. Post petiole with a low but broad lateral tubercle on each side. In profile the petiole peduncle short, with a small triangular anteroventral process and with a very small sub-denticulate process dorsally. The node itself higher than long, the lateral and posterior tubercles distinct. Sides of first gastral tergite in dorsal view curving evenly away from the articulation with the post petiole, without a sharp, flattened appearance. Head, alitrunk, petiole and pcstpetiole very finely and very densely superficially reticulate-punctulate, without rugulose sculpture. First gastral tergite with only the faintest vestiges of superficial sculpture basally. Dorsal surfaces of head and body with scattered very short blunt stout hairs; such hairs absent from appendages and sides of head but one or two may project from the curved part of the occipital corner on each side. Colour uniform pale yellow.

References

Arnold, G. 1948. New species of African Hymenoptera. No. 8. Occas. Pap. Natl. Mus. South. Rhod. 2: 213-250 (page 223, fig. 10 worker described)
Bolton, B. 1982. Afrotropical species of the myrmecine ant genera Cardiocondyla, Leptothorax, Melissotarsus, Messor and Cataulacus (Formicidae). Bulletin of the British Museum (Natural History). Entomology, 46: 307-370 (page 332, see also)
Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 272, Combination in Nesomyrmex)
Brown, W. L., Jr. 1971a. Characters and synonymies among the genera of ants. Part IV. Some genera of subfamily Myrmicinae (Hymenoptera: Formicidae). Breviora 365: 1-5 (page 4, Combination in Leptothorax)
Hita Garcia, F., Mbanyana, N., Audisco, T.L. & Alpert, G.D. 2017. Taxonomy of the ant genus Nesomyrmex Wheeler (Formicidae, Myrmicinae) in the Afrotropical region, with a review of current species groups and description of a new species of the N. angulatus group from Mozambique. European Journal of Taxonomy 258: 1–31 (DOI:10.5852/ejt.2017.258).
Mbanyana, N. and H.G. Robertson. 2008. Review of the ant genus Nesomyrmex in southern Africa. African Natural History. 4:35-55.

References based on Global Ant Biodiversity Informatics

Hita Garcia F., Mbanyana N., Audisio T. L., and G. D. Alpert. 2017. Taxonomy of the ant genus Nesomyrmex Wheeler (Formicidae, Myrmicinae) in the Afrotropical region, with a review of current species groups and description of a new species of the N. angulatus group from Mozambique. European Journal of Taxonomy 258: 1–31.
IZIKO South Africa Museum Collection
Mbanyana N., and H. G. Robertson. 2008. Review of the ant genus Nesomyrmex (Hymenoptera: Formicidae: Myrmicinae) in southern Africa. African Natural History 4: 35-55.