| Lachnomyrmex amazonicus|
Feitosa & Brandão, 2008
Lachnomyrmex amazonicus is known from Amazonian Brazil, in 60–200m elevation rainforest. It is one of the few species in the genus occurring in lowland forests rather than in submontane localities. All records refer to workers obtained in samples of sifted litter from the forest floor.
- 1 Identification
- 2 Distribution
- 3 Biology
- 4 Castes
- 5 Nomenclature
- 6 References
Feitosa and Brandão (2008) - Body irregularly rugose; promesonotum in profile elevated well above the level of propodeum; metanotal groove weakly impressed to obsolete; propodeal spines slightly directed upwards; teeth of propodeal lobes reduced; dorsum of postpetiole with more than 10 long, flexuous hairs; first gastral tergite entirely devoid of long hairs. The general habitus of this species allies it with Lachnomyrmex longinoi, Lachnomyrmex nordestinus, Lachnomyrmex plaumanni, and Lachnomyrmex victori. These species share the irregular body sculpturation, the obsolete metanotal groove, and the absence of long hairs on the first tergite of gaster. However, L. amazonicus can be distinguished from these species by the combination of promesonotum strongly convex, propodeal spines directed upwards, and dorsum of postpetiole bearing more than 10 long hairs.
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Distribution based on Regional Taxon Lists
Distribution based on AntMaps
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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)
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- amazonicus. Lachnomyrmex amazonicus Feitosa & Brandão, 2008: 11, figs. 2, 20 (w.q.) BRAZIL.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Holotype. HL 0.58; HW 0.58; ML 0.16; SL 0.31; EL 0.11; WL 0.66; PSL 0.14; PL 0.28; PPL 0.13; GL 0.76; TL 2.57; CI 100; SI 54; OI 18. (n=6). HL 0.52–0.66; HW 0.54–0.66; ML 0.16–0.21; SL 0.31–0.41; EL 0.08– 0.13; WL 0.57–0.74; PSL 0.11–0.17; PL 0.22–0.29; PPL 0.12–0.15; GL 0.68–0.82; TL 2.26–2.84; CI 100– 103; SI 50–63; OI 13–19.
Color dark reddish-brown to blackish, with waist and gaster slightly lighter; appendages yellowish to light brown. Body densely covered by vermiculate 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 short longitudinal striae restricted to basal portion; petiole and postpetiole finely and irregularly rugose. Abundant pilosity on head and mesosoma dorsum; dorsum of petiolar node and postpetiole each with more than 10 long, flexuous hairs; first gastral tergite entirely devoid of long hairs.
Head as long as broad, with vertexal margin weakly convex; frontal lobes laterally rounded; eyes with about seven facets on maximum diameter. Promesonotum strongly convex in profile, elevated well above the level of propodeum; metanotal groove shallow to virtually obsolete; propodeal spines slightly directed upwards; teeth of propodeal lobes reduced, with around 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.
Differing from worker by the larger eyes, with around 14 facets at maximum diameter; propodeal spines straight, without the apexes curved upwards.
Holotype worker. BRAZIL: Pará: Parauapebas, Fl. Nacional de Carajás, Garagem, 06º02'54S 50º04'55W, 25.iv–02.v.2008, Rogério R. Silva col., no. 5 Museu de Zoologia da Universidade de Sao Paulo. Paratypes. same data as holotype, no. 1 (1 worker) California Academy of Sciences; same data, no. 4 (1 worker) Laboratório de Mirmecologia CEPEC / CPDC same data (1 worker) Museo de Historia Natural, Bogata; same data, no. 5 (1 worker) National Museum of Natural History; same data (1 worker) William and Emma Mackay; same data, nos. 1/2/3/4/5 (5 workers and 3 gynes) [MZSP]; BRAZIL: Amazonas: Manaus, 22.ix.1993, A.B. Casimiro col., no. 4829 (1 worker) Instituto Nacional de Pesquisas da Amazonia; iii-iv.1994, R. Didham col. (3 workers) The Natural History Museum; same data (1 worker) [MZSP]; Mato Grosso: Alta Floresta, 10º47'S 56º49'W, 28.iv.1999, H.L. Vasconcelos col. (1 worker) [INPA]; Pará: Melgaço, Caxiuanã, 1º44'9S 51º29'15"W, 27–29.i.2003, A.Y. Harada, E.P. Fagundes, P. Batra, R. Calisto & Mó cols, no. 5 Museu Paraense Emilio Goeldi; 1º45'15S 51º31'20"W, 23–25.i.2004, A.Y. Harada, E. P. Fagundes, R. Calisto & Mó cols, no. 5 (1 worker) [MZSP]; Parauapebas, Fl. Nacional de Carajás, Casa de Hóspedes, 06º03'41S 50º03'13W, 25.iv–02.v.2008, Rogério R. Silva col., no. 1 (1 worker) [MZSP]; Núcleo Urbano, 06º03'53S 50º03'42W, 25.iv–02.v.2008, Rogério R. Silva col., no. 1 (1 worker) [MZSP]; Zoobotânico, 06º03'41S 50º03'13W, 25.iv–02.v.2008, Rogério R. Silva col., no. 1 (1 worker) [MZSP].
The name refers to the region from where this species is known, the Amazon Basin.
- 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.