| Lachnomyrmex longinodus|
Fernández & Baena, 1997
The two workers known for this species, the singleton worker holotype and a second singleton collection, were collected in the leaf litter of montane wet forests in the occidental slope of the Colombian Andes.
Feitosa and Brandão (2008) - Body slender, with fine and primarily longitudinal rugulation; propodeal spines at least twice longer than the distance between their basis; petiole elongate, at least three times longer than broad, in dorsal view; first tergite of gaster sparsely covered by long flexuous hairs. This species is immediately recognizable by the singular body sculpturation, slender mesosoma, and the long propodeal spines and petiole. The only non type (worker) presents some slight differences in comparison to the holotype, including longer body rugulation and denser pilosity. These differences could be an effect of the bad condition of the holotype, which has the head mounted apart from the body, antennae lacking apical segments, and the body covered by a great quantity of glue.
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Distribution based on Regional Taxon Lists
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Very little is known about the biology of these cryptic ants. Workers are frequently found in leaf litter and soil samples processed in Winklers or Berlese extractors, but these ants are never especially abundant within samples. When a dealate gyne is found associated with workers in 1m2 samples of leaf litter, normally it is found singly, which suggests that colonies are relatively small and apparently monogynic; workers and nests are extremely difficult to spot in the field, because the workers are very slow moving and well camouflaged; if there is any leaf-litter nest structure, it is destroyed during sifting, but our impression is that they do not construct any permanent nidal structure. Species of Lachnomyrmex apparently nest within the leaf litter, inside natural cavities of the superficial soil layers, fallen logs, and rotten wood, as evidenced by the large number of soil-covered individuals collected, from information recorded in specimen label data, and from observations of collectors. Workers forage alone, in the leaf litter and in the low vegetation, occasionally among epiphytes and moss, probably preying on small soft-bodied arthropods and possibly harvesting plant exudates. (Feitosa and Brandao 2008)
Known only from the worker caste.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- longinodus. Lachnomyrmex longinodus Fernández & Baena, 1997: 110, fig. 1 (w.) COLOMBIA. See also: Feitosa & Brandão, 2008: 23.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Feitosa and Brandão (2008) - Holotype measurements. HL 0.72; HW 0.63; ML 0.24; SL 0.49; EL 0.15; WL 0.85; PSL 0.26; PL 0.39; PPL 0.16; GL 0.87; TL 4.49; CI 87; SI 77; OI 24. Worker (n=1). HL 0.69; HW 0.63; ML 0.24; SL 0.52; EL 0.16; WL 0.84; PSL 0.24; PL 0.36; PPL 0.16; GL 0.82; TL 4.37; CI 90; SI 82; OI 25.
Body and appendages reddish to dark brown, contrasting with darker gaster. Head and mesosoma with long, fine, predominantly longitudinal rugulation; mandibles almost entirely smooth and shining, with very short longitudinal striae restricted to the most basal portion; rugae transverse on anterior portion of pronotum, grading to longitudinal on rest of mesosoma; lateral surfaces of pronotum, meso and metapleura, dorsum of propodeum, coxae, and waist coarsely punctate. Pilosity very long, slightly denser on appendages; dorsum of petiole and postpetiole each with around eight long hairs; first tergite of gaster sparsely covered by long flexuous hairs.
Head visibly longer than broad, with vertexal margin only discretely convex; frontal lobes somewhat reduced and rounded laterally; antennal scrobes relatively narrow; eyes well developed, with around nine facets at greatest diameter. Mesosoma considerably slender; promesonotum moderately convex in profile, but well above propodeum level; metanotal groove shallow and broad, with an ill definite posterior limit; propodeal spines straight and very long, about two times longer than the distance between its bases; teeth of propodeal lobes well developed and acute, with little less than propodeal spines half-length. Petiole elongate, around three times longer than broad in dorsal view; petiolar node low, dorsally rounded, and with posterior margin only minimally sloped in lateral view; postpetiole with dorsal surface convex and ventral surface without projections.
Feitosa and Brandão (2008) - Holotype worker, COLOMBIA: Nariño: Barbacoas, Reserva Natural Privada Río Nambí, 1200–1300m, 30.iv.1994, F. Escobar col., no. 0423 [ICNC] (examined). This specimen has the head mounted apart from the body, antennae lacking apical segments, and the body covered by a great quantity of glue.
Feitosa and Brandão (2008) - The authors (Fernández & Baena 1997) named this species after its long petiolar node. From Latin, longi: long and nodus: node.
- Feitosa, R.M. & Brandão, C.R.F. 2008. A taxonomic revision of the Neotropical myrmicine ant genus Lachnomyrmex Wheeler (Hymenoptera: Formicidae). Zootaxa 1890, 1-49.
- Fernández, F.; Baena, M. L. 1997. Hormigas de Colombia VII: nuevas especies de los géneros Lachnomyrmex Wheeler y Megalomyrmex Forel (Hymenoptera: Formicidae). Caldasia 19: 109-114 (page 110, fig. 1 worker described)