Feitosa & Brandão, 2008
The only known Lachnomyrmex platynodus specimen was collected in a leaf litter sample from a sub-montane wet forest (1300m) at Mt. Ayanganna, Guyana.
Feitosa and Brandão (2008) - Body predominantly blackish and irregularly rugose; promesonotum strongly convex and elevated well above propodeum level; metanotal suture obsolete; teeth of propodeal spines relatively thin; petiolar node dorsally flat, without a posterior slope; postpetiolar dorsum only minimally convex and mostly smooth; first tergite of gaster with around five long flexuous hairs. This species is known only by the holotype; however, it is unlikely to be confounded with any other congener. The combination of blackish color, dorsum of waist predominantly smooth, petiolar node flat, and first gastral tergite with a few sparse hairs is unique in the genus.
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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.
- platynodus. Lachnomyrmex platynodus Feitosa & Brandão, 2008: 34, figs. 13, 18 (w.) GUYANA.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Holotype measurements. HL 0.72; HW 0.72; ML 0.22; SL 0.46; EL 0.14; WL 0.87; PSL 0.16; PL 0.35; PPL 0.19; GL 0.94; TL 3.28; CI 101; SI 63; OI 19.
Color predominantly black, with ferruginous reflections, appendages dark brown. Body covered by vermiculate, relatively sparse short rugae, forming irregular areolae on promesonotum; rugae somewhat longer and longitudinal on head dorsum, and slightly sparser on mesopleura and lateral surfaces of propodeum; mandibles with longitudinal striae barely visible and almost reaching the masticatory margin; lateral faces of petiole and postpetiole irregularly rugose; dorsum of petiolar node and postpetiole predominantly smooth, with a few short, fine irregular rugae. Abundant pilosity, except by dorsal surface of propodeum; dorsum of petiolar node and postpetiole each with more than 10 long hairs; first gastral tergite with around five long, sparse flexuous hairs.
Head as long as broad, with vertexal margin virtually flat; frontal lobes subquadrate; eyes with approximately five facets on maximum diameter. Promesonotum strongly convex in profile, elevated well above the propodeum level; metanotal groove obsolete, so that the promesonotum outline reaches the propodeum in a slight declivity; propodeal spines straight; teeth of propodeal lobes relatively thin, slightly surpassing propodeal spines half-length. In lateral view, petiolar node moderately elevated and flat, without a posterior slope; postpetiole somewhat elongate and only weakly convex, with sternite feebly projected.
Holotype worker. GUYANA: Guyana Esequiba: Mt. Ayanganna, 5º22.483N 59º57.969W, 13.x.2002, T.R. Schultz, J. Lapolla, C. Marshall & R. Williams cols, no. 413878, specimen code CASENT0173881 [USNM].
This is species is named after its flat petiolar node. From Greek, platy: flat and from Latin, 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.