Atta (Acromyrmex) jamaicensis André , 1893: 149. Two syntype workers, Jamaica (repository unknown) [not examined];
Atta (Trachymyrmex) jamaicensis André ; Wheeler 1907: 712 [Description of queen and male; combination in Atta (Trachymyrmex) ];
Trachymyrmex jamaicensis ( André ) ; Gallardo 1916: 242 [Combination in Trachymyrmex ]
Atta (Trachymyrmex) sharpii Forel , 1893: 372. Syntype worker(s) worker, near Brighton Estate , St. Vincent
Atta (Trachymyrmex) sharpii Forel ; Wheeler 1907: 712 [Synonymy, under Atta (T.) jamaicensis ( André ) ], [See Mayhé- Nunes and Brandão (2007: 15) for further discussion about synonymies of Atta (T.) sharpii Forel ]
Atta (Trachymyrmex) maritima Wheeler , 1905: 107. Syntype workers, Andros and New Providence Islands , Bahamas
Atta (Trachymyrmex) maritima Wheeler ; Wheeler 1907: 712 [Synonymy, under Atta (T.) jamaicensis ( André ) ]
Acromyrmex (Trachymyrmex) jamaicensis var. maritima Mann , 1920: 428. Syntype workers, Mangrove Cay, Andros Island and Bluff, Eleuthera Island , Bahamas , [Mann revived Atta (Trachymyrmex) maritima Wheeler from synonymy as variety of Acromyrmex (Trachymyrmex) jamaicensis ( André ) ]
Trachymyrmex jamaicensis var. maritima (Mann) ; Kempf 1972: 253 [Combination in Trachymyrmex ]
Trachymyrmex jamaicensis var. maritima (Mann) ; Mayhé-Nunes and Brandão 2007: 13 [Synonymy, under T jamaicensis ]
Trachymyrmex jamaicensis var. frontalis Santschi , 1925: 238. Worker, Diquini , Haiti
Trachymyrmex jamaicensis var. frontalis Santschi ; Mayhé-Nunes and Brandão 2007: 13 [Synonymy, under T. jamaicensis ]
Trachymyrmex jamaicensis subsp. cubaensis Wheeler , 1937: 459. Syntype workers, coast below Pico Turquino, Sierra Maestra , Cuba
Trachymyrmex jamaicensis subsp. cubaensis Wheeler ; Mayhé-Nunes and Brandão 2007: 13 [Synonymy, under Trachymyrmex jamaicensis ]
Diagnosis
Worker: HL 1.2-1.35, HW 1.35-1.45, CI 107-113, SL 1.2-1.25, SI 86-89, ML 2-2.1. A large, relatively slender species with relatively long antennae and legs. Antennal scapes surpass posterior corners of head by 1-2 times their maximum diameter. Head shape slightly longer than broad (CI 107-113) in full-face view, sides subparallel behind the eyes, slightly tapering anteriorly between the eyes and mandibular insertions. Posterior margin moderately concave. Clypeus with row of coarse, long hairs on anterior margin, projecting forwards over the dorsal surface of the mandibles; in side view a few shorter erect hairs often present posterior to the anterior row. Preocular carinae relatively short, stopping at about 1/3 the distance between eye and posterior corner of head, always subparallel to frontal carinae, not traversing antennal scrobe. Frontal carinae long, reaching back to posterior corner of head. Antennal scrobe well developed but shallow, extending above the posterior margin of the head as a small tooth. In full-face view, frontal lobes broad, rounded, symmetrical in shape. Anterolateral promesonotal tooth long, thin, sharply pointed, projecting forward and upwards. Propodeal teeth sharply pointed, variable in size, approximately as long as the distance between their bases. Head and mesosoma sparsely tuberculate, with small tuberculi bearing short, fine, recurved setae. In full-face view, two ridges are present on the posterior third of head, between the frontal carinae. Gaster strongly tuberculate, in dorsal view tuberculi form four more or less distinct longitudinal ridges on first gastric tergite. Color dark reddish-black or gray-black, appendages and two petiolar segments usually a lighter reddish-brown.
Queen: HL 1.25, HW 1.6-1.7, CI 128-136, SL 1.15-1.2, SI 68-75, ML 2-2.05. As in worker diagnosis but with typical caste-specific mesosomal morphology related to wing-bearing and head with small ocelli. In dorsal view, dorsolateral pronotal teeth large and conspicuous, sharp, narrowly triangular. Ventrolateral pronotal teeth large, lobelike (rarely triangular). Mesoscutum with coarse, longitudinal, finely tuberculate rugulae; tuberculi bearing short, stiff, slightly recurved suberect setae. Posterior portion of scutellum bearing two prominent lobelike teeth projecting posteriorly. Pronotal sides, mesopleura, and propodeum with only a few miniscule tuberculi, if any.
Male: HL 0.72-0.75, HW 0.69-0.75, CI 96-100, SL 0.87-0.99, SI 121-139, ML 2.1-2.4. A comparatively large male with relatively long appendages and antennal scapes. Posterior corners of head much rounded in full-face view, ocelli very large, elevated above remainder of head, forming a short, vertical "turret " in side view. Dorsolateral pronotal teeth unique, taking the form of thin, needlelike spines. Ventrolateral teeth absent. Gaster finely tuberculate, each tubercle bearing a short erect to suberect more or less recurved seta.
Discussion
Trachymyrmex jamaicensis is a unique species in the context of the US American fauna. No other Trachymyrmex shows the combination of large body size, dark coloration, almost quadrate head shape, antennal scrobes extending to posterior corners of head, long scapes, and four tuberculate longitudinal ridges on the first gastric tergite.
Etymology
André (1893) described T. jamaicensis based on two worker specimens collected by M. Fox in Jamaica (no date given). The species name obviously refers to the Caribbean island on which the types were collected.
Biology
In the United States T. jamaicensis occurs only in southeast Florida and the Florida Keys, but it is also widely distributed through much of the Caribbean (see distribution map). Smith (1954) suggested that Trachymyrmex jamaicensis is a non-native species that was recently introduced from the Caribbean, whereas Deyrup(1994) argues for an early, natural introduction because of morphological differences between the Florida and Caribbean populations. A thorough study of population genetics and morphology would be required to test these hypotheses.
In Florida, T. jamaicensis inhabits coastal tropical hardwood hammocks on shallow, sandy, coralline-rock-derived soils. Nests usually have several chambers; Weber (1967) found eight chambers in a colony excavated in the Bahamas. Based on partial nest excavations, Wheeler (1905, 1907) estimated that T. jamaicensis colonies contain 150 to several hundred workers. Due to the increasing urbanization of the coastline, Deyrup (1994) considers T. jamaicensis potentially endangered in Florida, which would give T. jamaicensis the distinction of being the first endangered fungus-growing ant species (IUCN 2006).
Additional material examined: BAHAMAS : Andros Island ( WM Wheeler, WM Mann ) ; Bimini Island ( NA Weber ) ; Eleuthera, Rainbow Bay ( DB & RW Wiley, JR Wiley ) ; San Salvador ( Deyrup ) ; HAITI : Diquini ( WM Mann ) , Manneville ( WM Mann ) , Port du Prince ( WM Mann ) ; PUERTO RICO : Culebra Island ( WM Wheeler ) , Guánica State Forest ( JT Longino ) ; U.S.A. : Florida , Broward County : Dania ( WF Buren ) ; Dade County : Elliot Key ( M Deyrup ) ; Martin County : Jonathan Dickinson State Park ( M Deyrup, L Davis ) ; Monroe County : Bahia Honda State Recreation Area ( M Deyrup ) , Big Pine Key, Watson's Hammock ( M Deyrup, EG Riley, PS Ward ) , Fat Deer Key ( UG Mueller ) , Grassy Key ( M Deyrup ) , Indian Key ( M Deyrup ) , Key Largo ( M Deyrup, UG Mueller ) , Long Key ( M Deyrup, EO Wilson ) , John Pennekamp Coral Reef State Park ( M Deyrup ) , Shark Key ( N Carlin, M Deyrup ) .
(Figs. 1-30)
Diagnosis: Monomorphic attine ants with the antennal scrobe margins always reaching and even surpassing the posterior margin of the head; frontal and preocular carinae well marked, subparallel throughout their whole extension, limiting the impressed antennal scrobe; extremities of frontal and preocular carinae always separate and with up to three triangular or rounded compressed tubercles or vertical teeth close to the posterior margin (figs 1, 5, 9, 13, 15, 19, 23, 27); preocular carina not curved mesad above eyes. Frontal lobes from moderately approximate to moderately expanded laterad, but in most species the interfrontal width near 2/3 of the head width across the eyes (FLI 50-70). Occipital projections (teeth or spines) always present on head. Posterior margin in full-face view smoothly concave, notched in the middle. The paired vertexal carinae indicated by a series of weakly connected piligerous denticles, flanking the shallowly impressed sagital furrow, which in front joins the transverse impression of frons, behind the frontal area. Outer border of mandibles sinuous. Mandibles with discal area smooth and shining, the fine striae confined to the mandibular bases and sides. All funicular segments, including 2nd, longer than broad.
Key to Trachymyrmex of the Jamaicensis species group (workers)
1 With the body in side view, length of lateral pronotal and anterior mesonotal projections notably different, either the mesonotal is much bigger than pronotal (Fig. 10), or appears as a multitubercular low tumulus (Fig. 16) ......................................................................................................................................................2
- Lateral pronotal and anterior mesonotal projections almost of the same size or the mesonotal a little shorter, but always spine-like......................................................................................................................3
2 Lateral pronotal spine-like projections shorter and slenderer than anterior mesonotal ones; midpronotal projections present; pronotal inferior corner and anterior margin of katepisternum unarmed; postpetiole in dorsal view trapezoidal, little broader behind than in front, its postero-dorsal border straight.................... ............................................................................................................ T. isthmicus Santschi (Figs 9-14, 30)
- Lateral pronotal spine-like projections longer than tumuliform and multituberculated anterior mesonotal ones; midpronotal projections absent or obsolete; pronotal inferior corner and anterior margin of upper region of katepisternum armed with a notable triangular tooth; postpetiole in dorsal view broader than long, its posterior border concave............................................................ T. ixyodusn. sp. (Figs. 15-18, 30)
3 Apically spatulate curved coarse hairs distributed over the whole body (Figs. 3, 26) ...............................4
- Curved coarse hairs apically spatulate absent over the whole body, except gaster....................................5
4 Antennal scape scarcely surpassing the posterior margin of head when lodged in the scrobe, with head in frontal view; anterior margin of the crenate frontal lobe with a protruded pointed tooth; propodeal spines distinctly longer than the distance between their inner bases (better seen in postero-dorsal view).............. ................................................................................................................... T. zeteki Weber (Figs 23-26, 30)
- Antennal scape surpassing the posterior margin by nearly a third of its length, when lodged in the scrobe, with head in frontal view; anterior margin of the smooth frontal lobe unarmed; propodeal spines distinctly shorter than the distance between their inner bases (better seen in postero-dorsal view)............................. .................................................................................................................. T. atlanticusn. sp. (Figs 1-5, 30)
5 Base of the anterior mesonotal spine thicker than the base of lateral pronotal ones; midpronotal projections absent or rarely represented by a pair of minute separate spines; supraocular projection spine-like; head and gaster darker than yellowish brown mesosoma; last funicular segments as dark as antennal scapes............................................................................................. T. jamaicensis ( André ) (Figs 19-22, 29)
- Base of the anterior mesonotal spine almost as thin as the base of lateral pronotal ones; midpronotal projection represented by a single truncate tooth; supraocular projection absent or vestigial; the whole body dark reddish brown; last funicular segments lighter than other antennal segments ..................................... ............................................................................................... T. haytianus Wheeler & Mann (Figs 5-8, 29)
(Figs. 19-22, 29)
Atta (Acromyrmex) jamaicensis André , 1893:149 (worker). Wheeler, 1907: 712 (gyne and male). Weber, 1966: 588 (figures of gyne and worker head). Kempf, 1972: 253 (catalog). Bolton, 1995: 420 (catalog).
Atta (Trachymyrmex) sharpii Forel , 1893: 372 (worker). Wheeler, 1907: 712 (synonymy).
Atta (Trachymyrmex) maritima Wheeler , 1905: 107 (worker). Wheeler, 1907: 712 (synonymy).
Acromyrmex (Trachymyrmex) jamaicensis var maritima : Mann, 1920: 428 (revived from synonymy). Kempf (1972: 253) catalog. Bolton (1995: 420) catalog NEW SYNONYMY .
Trachymyrmex jamaicensis var frontalis Santschi , 1925 (worker) NEW SYNONYMY .
Trachymyrmex jamaicensis cubaensis Wheeler , 1937 (worker). NEW SYNONYMY .
[Types not examined]
Worker measurements (n = 10). TL 5.3 (4.5-5.7); DHL 1.42 (1.23-1.49); HW 1.38 (1.25-1.48); IFW 0.83 (0.69-0.94); ScL 1.17 (1.08-1.31); HWL 0.86 (0.78-0.92); MeL 2.03 (1.75-2.18); PL 0.42 (0.32-0.48); PPL 0.53 (0.45-0.58); GL 1.48 (1.23-1.58); HfL 2.04 (1.75-2.18).
Worker description: Dark ferruginous, with lighter spots on coxae and inferior margin of pronotum; in most specimens, the head and gaster are darker than the rest of the body. Integument opaque and finely granulose. Pilosity: scarce very short curved hairs confined to body projections, more abundant on antennal scapes and gaster tip.
Head, in full face view (Fig. 19), from a little longer than broad to a little broader than long (DCI average 100; 92-117). Outer border of mandible feebly sinuous; eight teeth on chewing border, gradually diminishing in size towards base. Clypeus median apron without conspicuous projections. Frontal area shallowly impressed. Frontal lobe semicircular, moderately approximate to moderately expanded (FLI average 60; 50- 67), with faintly crenulated 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 the posterior margin of head; preocular carina posteriorly ending in the posterior margin of head as a stout blunt spine larger than the frontal carinae projections. Occipital spine slender and as long as the preocular carinae projections. Supraocular projection tuberculiform. Paired denticulate vertexal carinae indicated by a series of weakly connected piligerous denticles, flanking the shallowly impressed sagital furrow, which in front joins the transverse impression of frons behind the frontal area. Inferior corner of occiput, in side view, with a small denticulate ridge. Eye convex, weakly 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 tip of the preocular carinae projections by nearly one fourth of its length; gradually thickened towards apex, covered with small piligerous tubercles.
Mesosoma (Figs. 20, 21). Pronotal dorsum marginate in front and on sides; antero-inferior corner with a strong and blunt tooth; inferior margin smooth; pair of median pronotal teeth absent or, when present, very small and arising from a common or separate bases, their tip microtuberculated or acute, not projected above the tip of the stronger lateral pronotal spines, which point obliquely upwards (with the pronotum in frontal view). Anterior pair of mesonotal spines nearly of the same length of the lateral pronotal pojections, with more robust base and upward directed; the second smaller, but much stronger than the almost always absent third pair. Anterior margin of katepisternum smooth, without a projecting tooth. Metanotal constriction impressed. Basal face of propodeum laterally marginated by a row of two denticles on each side; propodeal spines as long as the distance between their inner bases. Hind femora varying from a little shorter to a little longer than mesosoma length.
Waist and gaster (Figs. 20, 22). Dorsum of petiolar node with one pair of truncate teeth, the sides parallel in dorsal view, with a series of lateral denticles; sternum without sagital keel. Postpetiole almost as long as broad in dorsal view, and shallowly impressed dorsally, with straight postero-dorsal border. Gaster, when seen from above, suboval. Tergum I with convex lateral faces separated from the dorsal face by a weak longitudinal row of piligerous tubercles on each side; anterior two thirds of dorsum with three glabrous shallow longitudinal furrows, separated by a pair of rows of piligerous tubercles. Sternum I without an anterior sagital keel.
Gyne and Male. See Wheeler (1907).
Material examined: BAHAMAS , Andros Island, Mangrove Cay , Mann col. 27 workers ( MZSP , USNM , CECL ) ; ibidem, v-vi, 1904 , W.M. Wheeler col. 4 workers ( MZSP ) ; Fresh Creek , Mann col. 15 workers ( MZSP , USNM , CECL ) ; Spanish Wells , Mann col. 6 workers ( USNM ) ; Blutt , Mann col. 9 workers ( MZSP , USNM , CECL ) ; South Bimini , 2.ix.1951 , C. & P. Vaurie , 1 worker ( USNM ) . CUBA , Soledad , 12.vi.1927 , W.S. Creighton , 6 workers ( MZSP ) ; Nueva Gerona Island , 12.xi.1927 , Creighton col. 6 workers ( MZSP , USNM ) . HAITI , Manneville , Mann col. 10 workers ( MZSP , USNM , CECL ) ; Diquini , Mann col. 6 workers ( MZSP , USNM ) . JAMAICA , Kingston , M. Grabham (?), 3 workers ( USNM ) ; St. Eliz. , Malvern, 380m [ 18° 57´N , 77° 43´W ], 12.iii.1984 , J. Longino , specimen code JTLC000006114 , 2 workers ( JTLC ) . PUERTO RICO , Mona Island , 31.xi.1944 , H.A. Beatty col., 4 workers ( MZSP , USNM ) . USA : Florida , Dania , (several dates in 1945 ), W.F. Buren , 35 workers ( MZSP , USNM , CECL ) ; Marathon , 28.ii.1946 , W.F. Buren , 9 workers ( MZSP , USNM ) ; Big Pine Key, 10m , 16.ix.1982 , P.S.Ward# 5745 , “ground forager, hard wood, hammock”, specimen code JTLC000006115 , 2 workers ( JTLC ) .
Comments: The described infraspecies of T. jamaicensis are, in our view, local varieties based more on the degree of development of character states than in their presence or absence. Wheeler (1907) proposed the first two synonymies of T. jamaicensis ( T. sharpii Forel and T. maritima Wheeler ) at a time when he believed that this was a single species of the genus widely distributed in the West Indies. Some years later, however, Wheeler (1937) described other varieties of T. jamaicensis , and Mann (1922) revalidated T. jamaicensis var. maritima in a new concept. Although we were not able to study type material of all these varieties, in our comparative studies of the many available Antillean samples of T. jamaicensis , we were not able to discern samples that could merit specific recognition. Based on this and on the minor characters the authors used to differentiate infraspecies forms of T. jamaicensis , we are proposing the synonymies above.
Trachymyrmex jamaicensis presents noticeable variation in color and several morphological characters. In relation to the typical Jamaican form, specimens from Haiti, Cuba, and Florida are darker and present more slender and a little longer lateral pronotal spines. Specimens from the Bahamas may have, in relation to the other localities, very slender lateral pronotal spines, relatively short projections on the tip of frontal and preocular carinae, as well as smaller second mesonotal projection pair, thinner occipital projections, and longer petioles. Some specimens from Cuba and Puerto Rico also present relatively long petioles. Workers from Cuba and Florida may have two midpronotal teeth, and in the case of some Florida specimens, arising from separate bases. All Florida specimens present mesosomal projections stouter than in other samples and more expanded frontal lobes in relation to specimens from other localities, but agree in all other details with the description we provide above.
Wheeler (1905) described the nesting habits of T. jamaicensis (cited by him as Atta [T.] maritima ), that prefer to nest in pure foraminiferous sand of the seashore at or just above the high water mark, but may be found more inland as well. The inconspicuous nests are surmounted by very flat moundlets, with a single somewhat eccentric entrance, leading to one to many small ovoid chambers. The fungus is nourished with buds, small flowers, bits of dead and living leaves and caterpillar excrement. The workers feign death when disturbed. Weber (1967) visited Bimini Islands in 1959 to examine nests of this species and to secure fungus cultures. He only found nests in the northwestern portion of the South Island among scrub vegetation. He described the nest entrance crater, which may attain up to 50mm height and 3 to 8 chambers, which can extend to a depth of 70cm. Not all chambers were filled with fungus gardens, that when present were in the form of friable lamellae suspended from rootlets. The ants foraged at night or early mornings, ceasing when the sun shone on nests. The workers feigned death or quickly ran into the crater when disturbed. The largest workers in the colony were responsible for the foraging or for bringing up sand from the nest, while the smallest and palest stayed inside the nest and took care of the fungus garden, to which they brought yellowish flower stamens, woody particles, green dicot leaf sections and possibly insect feces. Weber (1972) depicted a cluster of inflated hyphal ends freshly removed from a garden of T. jamaicensis and presented a drawing of ends of two hyphae, showing stages in the development of inflations.
Atta (Trachymyrmex) sharpi Forel , 1893 was synonymyzed with Trachymyrmex jamaicensis by Wheeler in 1907. Notwithstanding, Kempf (1972) cited this name as valid in his catalog, and so Bolton (1995) considered Kempf´s move as a revalidation of the name T. sharpi . However, Kempf commented on all taxonomic novelties he proposed in the catalog, not citing any Trachymyrmex in this list. Also, the Museu de Zoologia da USP keeps the original cards Kempf used to construct the catalog, but the information regarding Wheeler´s synonymy is missing in the cards related to T. sharpi . We interpret the citation in the catalog as an error and are thus not proposing again the synonymy of T. sharpi , with which we fully agree. This is not the case of T. maritimus , which was revived from synonymy by Mann (1920), cited by Kempf (1972) as a subspecies of T. jamaicensis , and that we consider now a synonym of T. jamaicensis .
The first known fossil of any fungus-growing ant, Trachymyrmex primaevus , was described by Baroni Urbani (1980) from several Dominican amber pieces. He compared this species with T. jamaicensis , the only known valid species of the island of Hispaniola at the time of the description, although he stated that the definite relationships of the fossil to the known recent Trachymyrmex species were not clear. Baroni Urbani´s reconstruction of T. primaevus workers clearly shows heavily longitudinally striate mandibles and preocular carinae curved inwards, characters shared with Trachymyrmex of the Septentrionalis group, distributed today all over the Americas, but hitherto unknown in Caribbean localities. We will deal formally with the fossil species and the Septentrionalis species group in a forthcoming paper.
