Lachnomyrmex laticeps 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 : 19-21

Lachnomyrmex laticeps Feitosa & Brandão , new species

Figures 6 , 18

Holotype worker. COSTA RICA: Heredia: 13Km NE Vara Blanca, 10º16'N 84º05'W, 15.ii.2001, R. Vargas col., no. INBIOCRI0003622583 [ INBC].

Paratypes. same data as holotype, no. INBIOCRI0003622582 (1 worker) [ MZSP]; same data, no. INBIOCRI0003622585 (1 worker) [ INBC]. COSTA RICA: Alajuela: Peñas Blancas, Refugio Eladio, 10º19'N 84º43'W, 800m, 7.iii.2006, J. Longino col., no. JTLC 000008160 (1 worker) [ MZSP]; same data, no. JTLC 000008161 (1 worker) [ CASC]; Heredia: 16km SSE La Virgen, 1050–1150m, 10º16'N 84º05'W, 17.iii.2001, INBIO-OET-ALAS transect, no. INB0003214022 (1 worker) [ USNM]; P.N. Braulio Carrillo, 10º20'N 84º02'W, 500m, 17.x.2005, TEAM-OET, no. INB0003679758 (1 worker) [ BMNH].

Worker diagnosis. Pilosity exceptionally dense on body, including the first tergite of gaster; vertexal margin of head considerably broad (HW> 0,73mm); metanotal groove shallow and broadly impressed, without a well definite posterior limit.

Holotype measurements. HL 0.83; HW 0.82; ML 0.30; SL 0.52; EL 0.14; WL 0.99; PSL 0.24; PL 0.42; PPL 0.21; GL 1.10; TL 3.86; CI 98; SI 63; OI 17.

Worker measurements (n=2). HL 0.77–0.83; HW 0.74–0.79; ML 0.29–0.30; SL 0.52; EL 0.12–0.13; WL 0.94–0.98; PSL 0.22–0.24; PL 0.39; PPL 0.20–0.22; GL 1.07; TL 3.69–3.78; CI 94–96; SI 66–70; OI 16.

Worker description. Color reddish to dark brown, with lighter appendages. Body finely and densely covered by vermiculate rugae, somewhat longer and longitudinal on cephalic dorsum, and slightly sparser on mesopleura and lateral surfaces of propodeum; mandibles with short striae restricted to basal portion; petiole and postpetiole strongly and irregularly rugose. Pilosity extremely abundant, except by dorsal surface of propodeum; dorsum of petiolar node and postpetiole and first gastral tergite densely covered by long flexuous hairs.

Head visibly longer than broad, with vertexal margin virtually flat and considerably broad; frontal lobes rounded laterally; eyes with about seven facets on maximum diameter. Promesonotum strongly convex in profile; metanotal groove broadly impressed, without a distinct posterior limit; propodeal spines straight to discretely directed upwards; teeth of propodeal lobes well developed, surpassing propodeal spines half-length. Petiolar node elevated and subtriangular in lateral view; postpetiole dorsally convex and with sternite somewhat projected.

Gyne. Unknown.

Etymology. The name refers to the broad vertexal border of the workers head. From Latin: latus: broad, ceps: head.

Comments. The excessively dense body pilosity and the dorsally flat head separate this species from the related Lachnomyrmex grandis and L. pilosus . The collections of L. laticeps so far were made during expeditions to 500–1100m mature wet forests in northern Costa Rica. There is a record of workers collected manually beneath a treefern trunk ( Longino 2007). John Longino found a L. laticeps nest in a clay bank above a small stream, at Refugio Eladio, 800m elevation in the Peñas Blancas river valley. There was a small flaskshaped entrance structure leading to a small chamber. The chamber contained a few workers only, no brood or sexuals (pictures in Longino op. cit.).

Figures

FIGURE 6. Holotype worker of Lachnomyrmex laticeps from Heredia, Costa Rica: A, head in full face view; B, lateral view. Image by John Longino, specimen INBIOCRI 0003622583.

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