Lachnomyrmex plaumanni

Feitosa and Brandão (2008) - This is species has been collected from northern Argentina to southeastern Brazil, along the submontane areas of the Brazilian Atlantic Forest (400–1200m). Despite the constant presence of L. plaumanni in leaf liter samples from the Atlantic Forest, all attempts to maintain colonies in artificial conditions so far have failed. Gynes and workers usually die a few days after capture. There is a single record of a L. plaumanni worker foraging in the vegetation. It was collected manually in a bromeliad fixed in a high live tree from Serra do Itapeti, state of São Paulo, Brazil (M.S. Morini, pers. comm.).

Identification
Feitosa and Brandão (2008) - Body sparsely covered by short, fine rugae; promesonotum elevated minimally above propodeum level; apex of propodeal spines curved downwards; teeth of propodeal lobes swollen and extremely reduced; dorsum of postpetiole with about six long hairs; first tergite of gaster entirely devoid of long flexuous hairs. Lachnomyrmex plaumanni is one of the smallest species in the genus and can be immediately recognized by the combination of sparse sculpturation, propodeal spines curved downwards, and dorsum of postpetiole with about six long hairs.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Brazil, Costa Rica.

Nomenclature

 *  plaumanni. Lachnomyrmex plaumanni Borgmeier, 1957: 125, figs. 47-52 (w.q.) BRAZIL. See also: Feitosa & Brandão, 2008: 34.

Worker
Feitosa and Brandão (2008) - Lectotype. HL 0.65; HW 0.63; ML 0.19; SL 0.38; EL 0.11; WL 0.71; PSL 0.14; PL 0.30; PPL 0.14; GL 0.79; TL 2.77; CI 97; SI 60; OI 17. Workers (n=58). HL 0.57–0.69; HW 0.57–0.68; ML 0.17–0.20; SL 0.35–0.42; EL 0.09– 0.14; WL 0.61–0.80; PSL 0.13–0.15; PL 0.25–0.35; PPL 0.11–0.14; GL 0.68–0.93; TL 2.51–3.07; CI 96–101; SI 56–65; OI 14–22.

Worker description. Color light reddish-brown to dark brown, with appendages lighter. Body sparsely covered by irregular short rugae, somewhat longer and longitudinal on head dorsum; mandibles with short longitudinal striae restricted to basal portion; petiole and postpetiole finely and irregularly rugose. Abundant pilosity on head and promesonotum dorsum; dorsum of petiolar node and postpetiole with about four and six long hairs, respectively; first gastral tergite entirely devoid of long flexuous hairs. Head as long as broad, with vertexal margin strongly convex; frontal lobes laterally rounded; eyes with about six facets on maximum diameter. Promesonotum moderately convex in profile, only discretely higher than level of propodeum; metanotal groove shallow to virtually obsolete; apex of propodeal spines distinctly curved downwards; teeth of propodeal lobes swollen and reduced, with less than one-third of propodeal spines length. Petiolar node moderately elevated, dorsally rounded, and with the posterior face weakly sloped in lateral view; postpetiole feebly convex dorsally and without ventral processes.

Queen
Feitosa and Brandão (2008) - (n=20). HL 0.58–0.71; HW 0.58–0.71; ML 0.17–0.25; SL 0.36–0.44; EL 0.13– 0.19; WL 0.73–0.91; PSL 0.13–0.16; PL 0.30–0.39; PPL 0.13–0.16; GL 0.79–1.02; TL 3.45–2.70; CI 97–102; SI 58–62; OI 21–28.

Differing from worker by the larger eyes, with around 12 facets at maximum diameter; propodeal spines relatively wider basally and with the apexes only minimally curved downwards.

Etymology
Feitosa and Brandão (2008) - Father Thomas Borgmeier (1957) named this species in honor of the Lithuanian entomologist, Fritz Plaumann (1902–1994), collector of the L. plaumanni type-series and known for his exhaustive work on the insect fauna of the state of Santa Catarina, Brazil. Plaumann is considered the most important insect collector of Latin America in the 20th century.

References based on Global Ant Biodiversity Informatics

 * Borgmeier T. 1957. Myrmecologische Studien, I. Anais da Academia Brasileira de Ciencias 29: 103-128.
 * Favretto M. A., E. Bortolon dos Santos, and C. J. Geuster. 2013. Entomofauna from West of Santa Catarina State, South of Brazil. EntomoBrasilis 6 (1): 42-63.
 * Feitosa, R.M. and C.R.F Brandao. 2008. A taxonomic revision of the Neotropical myrmicine ant genus Lachnomyrmex Wheeler (Hymenoptera: Formicidae). Zootaxa 1890:1-49
 * INBio Collection (via Gbif)
 * Kempf W. W. 1978. A preliminary zoogeographical analysis of a regional ant fauna in Latin America. 114. Studia Entomologica 20: 43-62.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
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 * Rosa da Silva R. 1999. Formigas (Hymenoptera: Formicidae) do oeste de Santa Catarina: historico das coletas e lista atualizada das especies do Estado de Santa Catarina. Biotemas 12(2): 75-100.
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 * Silva R.R., and C. R. F. Brandao. 2014. Ecosystem-Wide Morphological Structure of Leaf-Litter Ant Communities along a Tropical Latitudinal Gradient. PLoSONE 9(3): e93049. doi:10.1371/journal.pone.0093049
 * Suguituru S. S., D. R. de Souza, C. de Bortoli Munhae, R. Pacheco, and M. S. de Castro Morini. 2011. Diversidade e riqueza de formigas (Hymenoptera: Formicidae) em remanescentes de Mata Atlântica na Bacia Hidrográfica do Alto Tietê, SP. Biota Neotrop. 13(2): 141-152.
 * Suguituru S. S., M. Santina de Castro Morini, R. M. Feitosa, and R. Rosa da Silva. 2015. Formigas do Alto Tiete. Canal 6 Editora 458 pages
 * Suguituru S. S., R. Rosa Silva, D. R. de Souza, C. de Bortoli Munhae, and M. Santina de Castro Morini. Ant community richness and composition across a gradient from Eucalyptus plantations to secondary Atlantic Forest. Biota Neotrop. 11(1): 369-376.
 * Ulyssea M.A., C. E. Cereto, F. B. Rosumek, R. R. Silva, and B. C. Lopes. 2011. Updated list of ant species (Hymenoptera, Formicidae) recorded in Santa Catarina State, southern Brazil, with a discussion of research advances and priorities. Revista Brasileira de Entomologia 55(4): 603-611.