Cylindromyrmex darlingtoni

The most northern ranging species in the genus. The Cuban types were collected in decaying wood. A worker was also found collected from a rotten downed-log in a higher elevation wet forest in the Dominican Republic, Duarte Province.

Identification
De Andrade (1998) - A species belonging to the brevitarsus clade and resulting in an unresolved position together with brevitarsus and Cylindromyrmex electrinus, but differing from both bythe frontal carinae surpassing the anterior border of the clypeus, instead of as long as the clypeus, and by the mandibles with 9-10 denticles instead of 6-8. C. darlingtoni differs from electrinus by the mid and fore basitarsi shorter and broader distally instead of long and with parallel sides, and from brevitarsus, by the ventral face of the hind femora with only traces of longitudinal striae instead of markedly striate.

Wheeler (1937) - This species is peculiar in the structure of the mandibles in the worker and female, and in the retention of distinct promesonotal and mesoepinotal sutures by the former.

Distribution based on Regional Taxon Lists
Neotropical Region: Cuba, Dominican Republic, Greater Antilles.

Nomenclature

 *  darlingtoni. Cylindromyrmex (Hypocylindromyrmex) darlingtoni Wheeler, W.M. 1937b: 441 (w.q.) CUBA. See also: De Andrade, 1998a: 622.

Worker
Length 5.6-6 mm.

Head sub oblong, one third longer than broad without the mandibles, as broad in front as behind, with straight, parallel sides and angularly excised posterior borders. Eyes small, flat, nearly as long as the greatest diameter of the antennal scapes, one third as long as their distance from the posterior corners of the head and situated at its posterior two-fifths. Ocelli minute but distinct. Mandibles large and convex, with evenly rounded external borders, the apical borders broad, with about 10 subequal, low, blunt teeth. Antennal scrobes, clypeus and frontal lobes of the usual conformation. Frontal area distinct, elongate-lanceolate. Antennal scapes less than three times as long as broad; first funicular joint as broad as long, joints 2-7 more than twice as broad, 8th as broad as long, the large terminal joint as long as the 9th and 10th together. Thorax short, somewhat less than twice as long as broad, parallel-sided, semi circularly rounded behind, with rounded humeri and short neck; promesonotal and mesoepinotal sutures distinct, interrupting the sculpture but not impressed. In profile the thoracic dorsum is nearly flat, the sides of the pronotum marginate, of the meso- and epinotum submarginate, the declivity of the latter abrupt, forming nearly a right angle with the base. Petiole distinctly longer than broad, with a blunt tooth at each of its anterior corners, the node distinctly widened behind and in this region with rounded, convex sides; in profile the anterior surface is flat and perpendicular, the dorsal surface evenly convex. The anteroventral process of the petiole is large, subrectangular in profile, and laterally compressed. Postpetiole about one and two-thirds times as broad as the petiole and a third broader than long. Gaster long but not much broader than the postpetiole. Pygidium truncated posteriorly and beset with numerous spinules. Legs short, the femora and tibiae broad and flattened, the hind tarsi decidedly longer than the hind tibiae, which are furnished with a long and a short pectinated spur.

Shining; mandibles finely striate and coarsely punctate apically, smooth at the base; head including the scrobes, thorax, petiole and postpetiole rather finely striate, the striae occasionally interrupted by sparse, elongate, piligerous punctures; pleurae and first gastric segment more finely striated, but the latter only on the anterior half where it is also coarsely and sparsely punctate. Remaining gastric segments, scapes and legs smooth, with numerous fine, superficial punctures.

Erect hairs yellowish, sparse, delicate, moderately long, of uneven length. The anterior border of the gula bears a conspicuous fringe or tuft of bristles, and there are some long, sparse hairs along the ventral surface of the lateral borders of the mandibles and a few long deflected hairs on the anterior, truncated surface of the clypeus. Pilosity sparse on the legs, most abundant on the tarsi. Gastric segments distinctly pubescent.

Black; tips of scapes, funiculi, legs and pygidium brownish red. femora dark brown, terminal funicular joint and tarsi, except the basitarsi, paler and more yellow.

De Andrade (1998) - TL 6.52; HL 1.28; HW 1.08; EL 0.25; SL 0.54; SW 0.20; WL 1.64; PeL 0.58; PeW 0.60; HFeL 0.73; HFeW 0.33; HTiL 0.63; HTiW 0.23; HBaL 0.34; HBaW 0.08; CI 84.4; SI 37.0; HFeI 45.2; HTiL 36.5; HBaI 23.5.

Head ca. 1.5 times longer than broad, with parallel sides. Occiput high. Vertexal angles convex. Frontal carinae about half broad as the maximum head width. Frontal carinae anteriorly diverging backwards and reaching at the middle of the eyes posteriorly. Dorsum of the frontal carinae with an impressed, broad, median sulcus anteriorly. Frontal carinae slightly longer than the anterior border of the clypeus. Compound eyes small, flat and behind the mid line of the head. Impar ocellus minute, pair ocelli reduced to a superficial pit. Scapes almost reaching the anterior border of the eyes. Proximal third of the scape 1/2 narrower than the distal parts. Mandibles convex dorsally. Masticatory margin of the mandibles each with a series of 9-10 irregular denticles followed by an apical one.

Mesosoma convex dorsally and as long as the head (mandibles included). Pronotum with parallel sides. Promesonotal and propodeal sutures, superficially impressed. Mesonotum narrower than pronotum. Propodeal sides gently convex and converging posteriorly. Basal face of the propodeum separated from the declivous one by a faint margin.

Petiole subquadrate, slightly broader than long. anteriorly truncate and dorsally convex. Petiolar sides diverging backwards. Ventral process of the petiole large and subtriangular. Postpetiole ca. 1.3 broader than long. Postpetiolar sides gently diverging posteriorly. Postpetiole in dorsal view gently angulate antero-laterally. Postpetiolar sternite antero-medially with a superficial, triangular lip pointing backwards. Pygidium truncate; its sides bearing many irregularly distributed small denticles converging to small teeth over the sting.

Legs. Femora and tibiae lightly inflate. Fore and mid basitari strongly broadening distally. Hind basitarsi short, ca. 1/2 shorter than the maximum length of the hind tibiae. 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, thicker on the posterior third of the head dorsum, absent on the angles of the ventral part of the head. Mesosoma longitudinally striated, some mesosomal striae bifurcated. Dorsum of the pronotum with about 40 longitudinal striae similar to those on the posterior part of the head dorsum. Pronotal striae prolonging to the dorsum of the mesonotum and propodeum. Pleurae with thin, superficial, longitudinal striae, less impressed on the propleurae. Petiolar dorsum with about 30 striae similar to those on the pronotum. Petiolar sides with minute and superficial reticulation. Declivous face of the propodeum superficially and sparsely reticulate. Anterior face of the petiole smooth. Dorsum of the postpetiole densely covered by striae similar to those on the petiolar dorsum. Second gastric tergite with extremely thin, superficial, longitudinal striae on the center of the anterior half only. Postpetiolar sternite and remaining gastric segments smooth and with sparse punctures. Pygidium, border of the sternites, and legs superficially reticulate. Hind coxae with trace of longitudinal striae.

Pilosity. Body with pointed hairs of at least three lengths and distributed as follows: (1) long, erect to suberect, one on the external border of the scape, a pair between the frontal carinae and clypeus, rare on the mandibles, on the mesosoma, on the pedicel, on the gaster and on the legs, sparse on the pygidium; (2) shorter than the type (1) and sparsely distributed on the whole body: (3) shorter than the type (2), suberect on the head dorsum and mesosoma, subdecumbent on the pedicel, decumbent on the ventral part or the head, on the gaster and on the leg. In addition, the hypostomal bridge surrounded by a layer of hairs similar to the type (1) but appressed and apically curved.

Colour black. Mandibles and antennae browish red. Coxae and femora dark brown. Last funicular joint, tibiae and tarsomeres yellowish-orange, tarsi darker.

Queen
Length 7.5-8 mm.

Closely resembling the worker. The head is not longer in proportion to its width but the eyes are much larger though only feebly convex, as long as their distance from the posterior corners of the head. Ocelli larger than in the worker. Scapes broader, with their anterior border more strongly excised at the base. Thorax long; pronotum, without the neck, subtrapezoidal, nearly twice as broad as long, with straight, submarginate, posteriorly diverging sides. Promesonotal suture semicircular, distinct and impressed. Mesonotum and scutellum small and flat. Gaster longer than in the worker owing to a lengthening of the individual segments. Wings short (5 mm.)

Sculpture very much like that of the worker but the striae on the posterior portions of the mesonotum and scutellum and dorsal portion of the mesopleurae feeble or absent, so that these regions are smoother and more shining. Gaster more densely punctulate than in the worker. Pilosity and color as in that caste. Wings grayish hyaline, veins dark brown, pterostigma black.

De Andrade (1998) - TL 8.16-8.44; HL 1.34-1.36; HW 1.08-1.10; EL 0.46-0.47; SL 0.57; SW 0.21; WL 2.28-2.36; PeL 0.70-0.72; PeW 0.66; HFeL 0.76-0.77; HFeW 0.35-0.36; HTiL 0.66; HTiW 0.24; HBaL 0.40; HBaW 0.08; CI 80.6-80.9; SI 36.8; HFeI 45.4-46.0; HTiL 36.4; HBaI 20.0.

Very similar to the worker but differing from it in the following details: compound eyes very large, flat and mostly on the posterior part of the head; ocelli well defined; mesosoma broad medially: parapsidal furrows superficially impressed; petiole slightly longer than broad; anterior half of the mesonotum and of the scutellum with very thin, superficial striae; posterior half of the mesonotum and of the scutellum with few traces of short striae or simply smooth.

Type Material
Described from four workers and two females taken by Dr. Darlington June 30, 1936, in decayed wood on the Gran Piedra Range, Oriente, at an altitude between 2000 and 3000 ft.

De Andrade (1998) - Worker and gyne. Type locality: Cuba. Type material: 2 workers and 2 gynes labelled: “Gran Piedra Rge. Ote Cuba. 2-3000 ft., 30.VI. 1936. P. J. Darlington. MCZ cotype”, in, examined.