Lachnomyrmex nordestinus Feitosa & Brandão, 2008

Feitosa, Rodrigo M. & Brandão, Carlos Roberto F., 2008, A taxonomic revision of the Neotropical myrmicine ant genus Lachnomyrmex Wheeler (Hymenoptera: Formicidae), Zootaxa 1890, pp. 1-49 : 29-30

Lachnomyrmex nordestinus Feitosa & Brandão , new species

Figures 11 , 18

Holotype worker. BRAZIL: Paraíba: João Pessoa, Mata do Buraquinho, 07º08'24''S 34º51'33''W, 25.vii.2002, R.R. Silva & F. Eberhardt cols, no. 5 [ MZSP].

Paratypes. same data as holotype (1 worker) [ MZSP]; BRAZIL: Ceará: Maranguape, viii.2003, Y. Quinet col., no. 80 (2 workers) [ UFCE]; same data (1 worker) [ MZSP]; Pernambuco: Jaqueira, Usina Colônia, M. do Espelho, 30.vii.2003, A. Bieber & I. Leal cols, no. P.05 (1 gyne) [ UFPE]; Recife, Horto Dois Irmãos, 08º00'32''S 34º56'40''W, 15–24.vii.2002, R.R. Silva & F. Eberhardt cols, nos. 2/ 7/13/28 /32/34/36/38 (7 workers and 1 gyne) [ MZSP]; same data, no. 32 (1 worker) [ AMNH]; same data, no. 33 (1 worker) [ BMNH]; same data, no. 34 (1 worker) [ CASC]; same data, no. 36 (1 worker) [ CPDC]; same data, no. 38 (1 worker) [ ICNC]; Sergipe: Areia Branca, P. E. da Serra de Itabaiana, 10º45'54''S 37º19'57''W, 19–25.v.2003, R.R. Silva, B.H. Dietz & L.S. Ferreira cols, nos. 10/17/26 /30/46/47 (6 workers and 2 gynes) [ MZSP]; same data, no. 38 (1 worker) [ MIZA]; same data, no. 46 (1 worker) [ USNM]; same data, no. 46 (1 worker) [ WPMC].

Worker diagnosis. Promesonotum strongly convex and elevated well above the level of propodeum, in profile; metanotal groove obsolete; apex of propodeal spines slightly curved upwards; teeth of propodeal lobes reduced; dorsum of postpetiole with around six long hairs; first gastral tergite entirely devoid of long flexuous hairs.

Holotype measurements. HL 0.65; HW 0.65; ML 0.22; SL 0.38; EL 0.13; WL 0.72; PSL 0.19; PL 0.31; PPL 0.13; GL 0.80; TL 2.84; CI 100; SI 59; OI 19.

Worker measurements (n=16). HL 0.63–0.74; HW 0.61–0.72; ML 0.20–0.24; SL 0.37–0.46; EL 0.12– 0.14; WL 0.68–0.80; PSL 0.15–0.24; PL 0.30–0.36; PPL 0.11–0.14; GL 0.77–0.93; TL 2.71–3.18; CI 96–100; SI 59–67; OI 19–22.

Gyne measurements (n=3). HL 0.71; HW 0.69–0.71; ML 0.21–0.24; SL 0.44–0.46; EL 0.18–0.19; WL 0.90–0.94; PSL 0.19–0.20; PL 0.33–0.38; PPL 0.15–0.16; GL 0.93–0.98; TL 3.27–3.40; CI 98–100; SI 62– 66; OI 25–26.

Worker description. Color light brown to blackish, contrasting with yellowish appendages and gaster. Body densely covered by vermiculate short rugae, forming irregular areolae on promesonotum dorsum; 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 promesonotum dorsum; dorsum of petiolar node and postpetiole with around 10 and six long flexuous hairs, respectively; first gastral tergite entirely devoid of long hairs.

Head as long as broad to slightly longer than broad, with vertexal margin only minimally convex; frontal lobes laterally rounded; eyes with about six facets on maximum diameter. Promesonotum strongly convex in profile, elevated well above the level of propodeum; metanotal groove virtually obsolete; propodeal spines well developed and slightly directed upwards; teeth of propodeal lobes reduced, with approximately one-third of propodeal spines length. Petiolar node moderately elevated and rounded dorsally, with the posterior face weakly sloped in lateral view; postpetiole gently convex dorsally and without ventral processes.

Gyne. Differing from the conspecific worker by the larger size of eyes, with about 15 facets at maximum diameter; propodeal spines comparatively shorter and straight apically; petiolar node only feebly elevated; ad dorsum of postpetiole with more than 10 long flexuous hairs.

Etymology. The epithet nordestinus refers to the northeastern Brazil (from Portuguese: Nordeste), the geographical region where this species occurs.

Comments. This species is very similar to Lachnomyrmex amazonicus and L. victori , but can be readily distinguished mainly by the scarcer pilosity on postpetiole dorsum. Gynes of L. nordestinus can be separated from L. victori by the absence of long flexuous hairs on the dorsum of the first gastral tergite.

All specimens known for L. nordestinus were collected in the leaf litter of the northeastern Brazilian Atlantic Forest (100–800m). This biome is seriously threatened by human activity, especially in this region.

Figures

FIGURE 11. Paratype worker of Lachnomyrmex nordestinus from Pernambuco, Brazil: A, head in full face view; B, lateral view; C, dorsal view. Image by Michele Esposito, specimen CASENT 0173878.

FIGURE 18. Distribution maps for the Lachnomyrmex species (L. fernandezi, L. grandis, L. laticeps, L. lattkei, L. longinoi, L. pilosus, and L. platynodus).