Trachymyrmex jamaicensis, (Andre)

Rabeling, Ch., Cover, S. P., Johnson, R. A. & Mueller, U. G., 2007, A review of the North American species of the fungus-gardening ant genus Trachymyrmex (Hymenoptera: Formicidae)., Zootaxa 1664, pp. 1-53 : 11-13

T. jamaicensis ( Andre)

Atta (Acromyrmex) jamaicensis Andre , 1893: 149. Two syntype workers, Jamaica (repository unknown) [not examined];

Atta (Trachymyrmex) jamaicensis Andre ; Wheeler 1907: 712 [Description of queen and male; combination in Atta (Trachymyrmex) ];

Trachymyrmex jamaicensis ( Andre) ; 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 ( Andre) ], [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 ( Andre) ]

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 ( Andre) ]

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) , Guanica 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) .