Trachymyrmex haytianus Wheeler & Mann

Mayhé-Nunes, Antonio J. & Brandão, Roberto F., 2007, Revisionary studies on the attine ant genus Trachymyrmex Forel. Part 3: The Jamaicensis group (Hymenoptera: Formicidae), Zootaxa 1444, pp. 1-21 : 6-7

Trachymyrmex haytianus Wheeler & Mann new status

( Figs. 5–8 , 29)

Atta (Trachymyrmex) jamaicensis haytiana Wheeler & Mann, 1914: 41 (worker). Trachymyrmex jamaicensis haytianus: Kempf, 1972: 253 (catalog). Bolton, 1995: 420 (catalog). [Type material: lectotype and 8 paralectotypes examined]

Worker measurements (n = 3). TL 4.7 (4.5–4.9); DHL 1.28 (1.26–1.31); HW 1.28 (1.25–1.32); IFW 0.70 (0.69–0.71); ScL 1.08 (1.05–1.11); HWL 0.74 (0.68–0.78); MeL 1.82 (1.77–1.85); PL 0.34 (0.32–0.35); PPL 0.48 (0.45–0.51); GL 1.32 (1.25–1.37); HfL 1.84 (1.82–1.86).

Worker description: Uniformly dark ferruginous, with lighter tip of tarsi and funiculi. Integument opaque and finely granulose. Pilosity scarce; very short hook-like hairs confined to body projections, more abundant on antennal scapes and gaster tip.

Head, in full face view ( Fig. 5 ), as long as broad (DCI average 100; 99–101). Outer border of mandible feebly sinuous; masticatory margin bears two apical and seven equally smaller teeth. Clypeus median apron without projections. Frontal area shallowly impressed. Frontal lobes semicircular, moderately approximate (FLI average 54; 54–55), with faintly crenulate free border, lacking prominent denticles on the antero-lateral border. Frontal carina moderately diverging caudad, reaching the antennal scrobe posterior end in a small tooth at its posterior end at the vertexal margin; preocular carina posteriorly ending in the posterior margin of the head as one or two small teeth of almost the same size of frontal carinae projections. Occipital spines longer and stouter than carinae projections. Supraocular projections absent or vestigial. Inferior corner of occiput with a small ridge, in side view. Eye convex, surpassing the head lateral border, with 13 facets in a row across the greatest diameter. Antennal scape, when lodged in the scrobe, projecting beyond the tips of the preocular carinae projections by nearly one fourth of its length; gradually thickened towards apex, covered with small piligerous tubercles.

Mesosoma ( Figs. 5–7 ). Pronotal dorsum emarginated in front and on sides; antero-inferior corner with a strong and truncated tooth; inferior margin with small piligerous denticles; median pronotal tooth tip rather truncate, not projected above the tips of the stronger lateral pronotal spines, which point obliquely upwards, with the pronotum in frontal view. Anterior pair of mesonotal spines a little shorter than the lateral pronotal projections, directed upwards; the spine-like second and third pair gradually smaller and thinner. Anterior margin of katepisternum smooth, without a projecting tooth. Metanotal constriction shallowly impressed. Basal face of propodeum laterally marginated by a row of three denticles on each side; propodeal spines pointing obliquely and laterad, as long as the distance between their inner bases. Hind femora almost of the same length of mesosoma.

Waist and gaster ( Figs. 6–8 ). Dorsum of petiolar node with a pair of minute spines, the sides subparallel in dorsal view, the spiracles produced as small tubercular projections; sternum without sagital keel. Postpetiole trapezoidal in dorsal view, two times broader behind than in front, and shallowly impressed dorsally, with straight postero-dorsal border. Gaster, when seen from above, globose to suboval. Tergum I with convex lateral faces separated from the dorsal face by a longitudinal row of piligerous tubercles on each side; anterior two thirds of dorsum with three shallow longitudinal furrows separated by a pair of piligerous tubercles rows. Sternum I without an anterior sagital keel or prominent tubercles.

Gyne and male: Unknown.

Lectotype worker: HAITI: Petionville, Mann leg. [no date] (“cotype” deposited in USNM, examined, here designated).

Paralectotype workers: same data as lectotype (5 deposited in USNM, 2 deposited in MZSP, 1 deposited in CECL).

Material examined: JAMAICA: St. Eliz., Malvern, 380m [18o 57´N, 77o 43´W], 12.iii.1984, J. Longino, specimen code JTLC 000007615, 1 worker ( JTLC); St. James, Great R., 0–80m [18o 26´N, 77o 59´W], 17.iii.1984, J. Longino, specimen code JTLC 000007616, 1 worker ( JTLC).

Comments: Wheeler & Mann (1914) say that this species was described from several workers collected from a single colony. Although we found only three individuals clearly labeled as “cotypes”, the other six workers bear identical locality labels, and so were considered as paralectotypes. T. haytianus was originally proposed as a subspecies of T. jamaicensis . The brief description of Wheeler & Mann (1914) contained only characters that distinguished it from the typical form, such as shorter spines and tubercles on the posterior corners of the head, well-developed median pronotal tooth, and black coloration. The colony was found in a canyon; its nest was briefly described as follows: “The nest entrance opened directly on the surface of the ground and was not surrounded by a crater.” Jack Longino kindly sent us additional samples of this species, from Jamaica, so T. haytianus and T. jamaicensis are sympatric, strengthening our argument for the recognition of this form as a good species.

Figures

FIGURES 5 – 8. Scanning electron micrograph of Trachymyrmex haytianus, paralectotype worker from Haiti, Pettionville. 5. Head in frontal view; scale bar = 500 μm. 6. Mesosoma and waist in lateral view; scale bar = 500 μm. 7. Mesosoma in dorsal view; scale bar = 500 μm. 8. Waist and gaster in dorsal view; scale bar = 250 μm.