Lachnomyrmex longinoi

This ant has most commonly been found in leaf litter samples from wet forests (100–1200m) of Costa Rica and Panama.

Identification
Feitosa and Brandão (2008) - Body densely and irregularly rugose; metanotal groove obsolete; teeth of propodeal lobes well developed and projected over petiolar peduncle; petiolar node high and subtriangular; pilosity on dorsum of postpetiole exceptionally dense; first tergite of gaster completely devoid of long flexuous hairs. The well developed teeth of propodeal lobes allied to the dense pilosity on postpetiole dorsum separate this species from the related Lachnomyrmex amazonicus, Lachnomyrmex nordestinus, Lachnomyrmex plaumanni, and Lachnomyrmex victori. Gynes of L. longinoi can be confounded with Lachnomyrmex scrobiculatus by the subtriangular petiolar node and the presence of long hairs on first gastral tergite. However, gynes of L. scrobiculatus present an anteroventral projection in the postpetiole, which is absent in this species.

Key to Lachnomyrmex

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica, Honduras, Nicaragua, Panama.

Nomenclature

 *  longinoi. Lachnomyrmex longinoi Feitosa & Brandão, 2008: 25, figs. 9, 18 (w.q.) COSTA RICA.

Worker
Holotype HL 0.72; HW 0.74; ML 0.24; SL 0.43; EL 0.16; WL 0.84; PSL 0.19; PL 0.35; PPL 0.18; GL 0.88; TL 3.21; CI 102; SI 58; OI 21. Workers (n=20). HL 0.66–0.72; HW 0.65–0.74; ML 0.22–0.25; SL 0.39–0.46; EL 0.13– 0.17; WL 0.76–0.87; PSL 0.16–0.19; PL 0.31–0.36; PPL 0.16–0.19; GL 0.85–0.94; TL 2.98–3.32; CI 98–102; SI 58–66; OI 20–24.

Color dark brown to black, with lighter appendages. Body densely covered by vermiculate short rugae, forming irregular areolae on head and promesonotum, and slightly sparser on mesopleura and lateral surfaces of propodeum; mandibles with short longitudinal striae restricted to basal portion; petiole and postpetiole irregularly rugose. Abundant pilosity on head and promesonotum dorsum; dorsum of petiolar node with about six long hairs; dorsum of postpetiole densely covered by long flexuous hairs; first gastral tergite entirely devoid of long hairs.

Head as long as broad, with vertexal margin weakly convex; frontal lobes subquadrate; eyes with about seven facets on maximum diameter. Promesonotum elevated well above the level of propodeum in profile; metanotal groove virtually obsolete; propodeal spines straight; teeth of propodeal lobes widen basally and slight longer than the half-length of propodeal spines. Petiolar node elevated and subtriangular in lateral view; postpetiole strongly convex dorsally and without ventral projections.

Queen
(n=5). HL 0.65–0.79; HW 0.65–0.79; ML 0.21–0.24; SL 0.39–0.44; EL 0.17–0.20; WL 0.87–1.06; PSL 0.16–0.20; PL 0.36–0.43; PPL 0.17–0.24; GL 0.96–1.12; TL 3.24–3.86; CI 100–102; SI 56–61; OI 26–27.

Similar to worker. In addition, eyes with around 12 facets at maximum; wings with the basic pattern of venation for the genus; propodeal spines and teeth of propodeal lobes reduced; petiolar node comparatively lower; ventral face of postpetiole moderately projected; surface of first gastral tergite covered by long flexuous hairs, relatively dense anteriorly, becoming sparser posteriorly.

Type Material
Holotype worker. COSTA RICA: Guanacaste: Est. Pitilla, 9km S Sta. Cecília, LN 330200_380200, 16– 18.viii.1993, P. Ríos col., no. INBIOCRI0001657358 [INBC]. Paratypes. same data as holotype, no INBIOCRI001657147 (1 worker) [MZSP]; no INBIOCRI0001657202 (1 worker) [INBC]; COSTA RICA: Alajuela: Río San Lorencito, 1990, P. Hammond col. (2 workers) [BMNH]; same data (1 worker) [MZSP]; Guanacaste: Pitilla Field Station, 2.v.1995, R. Anderson col., no. 17721 (1 worker) [WPMC]; Heredia: La Selva, 15.iv.1985, J. Memmott col. (3 workers) [BMNH]; Limón: Cerro Cocori, Fca. de E. Rojas, vi.1991, E. Rojas col., no. INBIOCRI000636130 (1 worker) [INBC]; 30km N Cariari, i.1993, E. Rojas col., no. INBIOCRI000675271 (1 worker) [INBC]; Puntarenas: Península Osa, Aenn. Fund. Neotrop., 23.vi.1997, R. Anderson col., no. 18686/18687 (5 workers and 1 gyne) [WPMC]; same data (1 gyne) [MZSP]; same data (1 worker) [CASC]; same data (1 worker) [CPDC]; same data (1 worker) [USNM]; Cerro Helado, 15km NE Rincón, 24.vi.1997, R. Anderson col., no. 18689 (1 worker and 1 gyne) [WPMC]; Península Osa, Cerro Helado, 21.vi.1997, R. Anderson col., no. 18685 (2 workers and 1 gyne) [WPMC].

Etymology
This species is named in honor of Dr. John “Jack” Longino in recognition of his many years of devoted work on the ants of Costa Rica and for his valuable support during the elaboration of this work.