Cylindromyrmex escobari

Fernandez-C. & Escobar (1997) reported collecting the single type specimen, reported as C. brasiliensis, from decayed wood found in a forest. Costa Rican specimens have been collected from montane wet forest.

Identification
De Andrade (1998) - The basalmost species of the brevitarsus clade. Differing from all the other species by the antero-median margin of the clypeus convex and by the absence of striae on the gaster.

C. escobari differs from the other species of the brevitarsus clade mainly by the absence of striae on the first gastric tergite. In particula, it differs from Cylindromyrmex electrinus by the larger and more massive mandibles with 13-14 denticles instead of smaller and less massive and with 6-7 denticles. From Cylindromyrmex darlingtoni and Cylindromyrmex brevitarsus, escobari differs by the more elongate body. C. escobari in general body shape resembles more C. darlingtoni than brevitarsus. A comparison of escobari and darlingtoni proves that they are very different from each other. C. escobari can be separated from darlingtoni by the strongly convex anterior border of the clypeus by the frontal carinae not reaching the anterior clypeal border and by the more elongate femora.

Comparisons were made also between the worker of escobari and the gynes of Cylindromyrmex boliviae and Cylindromyrmex godmani, two species the workers of which are still unknown and occurring close to the area where escobari was collected. Escobari has concolour femora and tibiae (yellowish-orange to light brown) and godmani has black femora and yellow tibiae. Escobari differs from boliviae by the postpetiole striate instead of smooth or with very superficial, short striation restricted to the center of the posterior half, and by thinner striation.

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

Nomenclature

 *  escobari. Cylindromyrmex escobari De Andrade, 1998a : 616, fig. 17 (w.) COLOMBIA. De Andrade, 2001 : 57 (q. measurements).

Worker
TL 81.16; HL 1.56; HW 1.28; SL 0.732; SW 0.25; WL 2.16; PeL 0.68; PeW 0.56; HFeL 1.00; HFeW 0.37; HTiL 0.85; HTiW 0.26; HBaL 0.50, HBaW 0.09; CI 82.0; SI 34.7; HFeI 37.0; HTiL 30.5; HBaI 18.0.

Head ca. 1.5 time longer than broad with subparallel sides. Occiput high. Vertexal angles convex. Frontal carinae more than half broad as the maximum head width. Anterior third of the frontal carinae diverging backwards and reaching at least the middle of the eyes posteriorly. Dorsum of the frontal carinae with an impressed, broad, median sulcus anteriorly. Frontal carinae not reaching the anterior border of the clypeus. Antero-median clypeal margin strongly convex. Compound eyes intermediate in size between the species of the longiceps and striatus clade, light flat and on the posterior half of the head. Ocelli represented by superficial impression only. Scapes stout and surpassing the anterior border of the eye posteriorly. Proximal third of the scape 1/2 narrower than the remaining part. Mandible strongly convex dorsally. Masticatory margin of the mandibles each with, a set of 13-14 irregular denticles followed by an apical tooth.

Mesosoma gently convex dorsally and slightly less, than 1/5 longer than the head (mandibles included). Pronotum with parallel sides. Promesontal and propodeal sutures superficially impressed. Mesonotum slightly narrower than pronotum. Tegula superficially marked. Propodeum with the sides weakly convex. Basal face of the propodeum separated from the declivous one by a superficial margin.

Petiole rectangular, anteriorly truncate and the dorsally convex. Petiolar sides diverging backwards. Ventral process of the petiole large and subtriangular. Pospetiole ca. 1.5 broader than long. Postpetiolar sides diverging posteriorly. Postpetiole in dorsal view antero-laterally angulate. Postpetiolar sternite antero-medially with a superficial triangular “lip” pointing backwards. Pygidium in side view obliquely truncate. Pygidium in dorsal view with the sides bearing many irregularly distributed small denticles converging to 4 small teeth over the sting.

Legs. Coxae and tibiae slightly inflated. Mid basitarsi strongly broadening distally. Hind basitarsi about 1/3 shorter than the maximum length of the hind tibiae. Mid basitarsi 1/2 of the length of the hind basitarsi. Outer apical edge of the hind and of the mid basitarsi respectively with 4.5 spine-like setae.

Sculpture. Head covered by thin, longitudinal striae, slightly thicker on the posterior third of the head dorsum and on the center of the ventral part of the head absent on the posterior corners of the ventral pan of the head. Mesosoma longitudinally striated. Pronotum and mesonotum with striae thicker than those on the propodeum. Pronotum with about 28-30 longitudinal striae similar to those on the posterior part of the head dorsum. Propodeum with about 30-35 longitudinal striae. Pleurae with very thin, superficial, longitudinal striae, less impressed on the propleurae. Petiolar dorsum with about 30-35 striae slightly thinner than those on the propodeum. Petiolar sides with very thin, superficial striae. Declivous face of the propodeum and anterior face of the petiole with superficial reticulation. Dorsum of the postpeliole with striae thinner than those on the petiolar dorsum. Remaining gastric tergites, sternites and legs smooth, with minute, superficial reticulation more impressed on the distal segment of the gaster. Ventral face of the hind coxae with thin, longitudinal striae.

Pilosity. Body with pointed hairs of at least three length and distributed as follows: (1) long, erect to suberect, sparse on the head, on the mesosoma, on the pedicel and on the gaster, dense on the pygidium; (2) shorter than the type (1), suberect and variably distributed on the whole body: (3) shorter than the type (2), sparse, suberect or subdecumbent on the whole body. In addition, the hypostomal bridge surrounded by a layer of hairs similar to the type (1) but appressed and apically curved. Outer ventral border of the mandibles with hairs similar to those of the hypostomal bridge but shorter.

Colour black. Mandibles, antennae and coxae dark ferrugineous brown. Leg yellow-orange to light brown with darker tarsi. .

Type Material
Holotype: Worker labelled: “Colombia, Narino, Ricaurte La Planada, 1°17' N 78° 15' W. 1800 m, interior bosque, bmh-PM. Col: F. Escobar”, in.

Etymology
C. escobari is named after Federico Escobar, the collector of this species.

References based on Global Ant Biodiversity Informatics

 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.