Temnothorax palustris

The first known specimens were collected in pitfall traps, and this seems a good way to sample for the species. In a site where the species is known to occur, it can be baited with cookie crumbs. Our experience is that members of this species accept shortbread cookie crumbs with an enthusiasm not always seen in Temnothorax species, and immediately return to the nest. This may be the only practical way to find a nest, because the nest entrances that we have seen are completely unmarked holes about 2 mm in diameter. (Deyrup and Cover 2004)

Identification
Prebus (2017) - A member of the sallei clade.

Deyrup and Cover (2004) - This species resembles Temnothorax texanus Wheeler, a species of adjacent well-drained sandy sites, differing primarily in the structure of the petiole and postpetiole and color."

Distribution
Southeast United States. Known from the Apalachicola and Osceola National Forests, possibly occurs in marshes and flatwoods in Georgia and Alabama.

Distribution based on Regional Taxon Lists
Nearctic Region: United States.

Habitat
Frequently flooded and burned pine forests.

Abundance
Known from a few collections.

Nests in sandy soil, near the surface, in root mats that extend into small open sandy hummocks.

Nomenclature

 *  palustris. Leptothorax palustris Deyrup & Cover, 2004a: 52, figs. 1, 2 (w.q.m.) U.S.A. Combination in Temnothorax: new combination (unpublished).

Worker
Distinguished from all other Nearctic Temnothorax by the following combination of character states: head with fine, longitudinal, well-separated dorsal carinae, otherwise shining; mesosoma with fine, longitudinal, well-separated dorsal carinae, anastomosing dorsally; propodeal spines slender, acute, projecting distinctly upward from the smoothly convex dorsum of the mesosoma; postpetiole in dorsal view almost twice as wide as petiole, and almost as long as wide, shining; color yellowish, head yellowish brown. Most similar to Temnothorax texanus Wheeler, but postpetiole relatively longer, color lighter.

Features visible in lateral view described from left side. Head: dorsum with fine, well-separated, longitudinal, irregular carinae, with scattered, short cross-carinae; interstices weakly shining; clypeus with a strong median carina, separated by a distance equal to about half its length from the sublateral longitudinal carinae, a lateral carina also present on each side; malar space slightly more than 1.5 times maximum length of eye; antennae with 12 joints. Mesosoma: evenly convex in profile; dorsum with a few coarse carinae forming a rough network, interstices weakly shining; pronotum and mesopleuron each with several irregular, indistinct longitudinal carinae, interstices weakly shining; metapleuron with five distinct longitudinal carinae, interstices shining; propodeal spines long, slender, in lateral view spine making a 135 degree angle with the dorsum of the mesosoma; petiole in profile concave ventrally, with a small, sharp angle at anterior border; node of petiole with a blunt anterior angle, no posterior angle; postpetiole in dorsal view shining anteriorly, minutely roughened posteriorly; 1.8 times as wide as petiole; postpetiole as long as wide when measured from side to side at midlength, and along midline from convex anterior to convex posterior borders. Gaster: shining, without sculpture. Dorsum of head and body with sparse, flattened, parallel sided hairs, erect on head and mesosoma; slightly retrorse on petiole, postpetiole, and gaster. Color: translucent dark yellow, dorsum of head brown, middle and hind femora with wide postmedian bands of brownish yellow. Measurements in mm: Total length (length of head excluding mandibles, + length of mesosoma, excluding propodeal spines, + length of petiole, postpetiole, gaster): 2.90; head length 0.65; head width 0.50; length of mesosoma: 0.93; length of petiole: 0.25; length of postpetiole: 0.27; length of gaster: 0.80.

Queen
Queens of some North American Temnothorax are unknown or undescribed; this diagnosis includes only species from southeastern North America. Distinguished from these by the following combination of character states (Fig. 2): mesopleuron shining, with only a few fine carinae near edges (unlike Temnothorax smithi Baroni Urbani, schaumii Roger; bradleyi Wheeler); propodeal spines long, slender (unlike pergandei Emery, bradleyi); propleuron with conspicuous irregular carinae (unlike tuscaloosae Wilson, torrei (Aguayo), pergandei ); petiole in profile triangular with a single single conspicuous dorsal angle, not rounded dorsally (as in allardycei (Mann)), or truncate and biangulate (as in longispinosus Roger and texanus Wheeler); maximum length of eye slightly shorter than malar space (unlike curvispinosus Mayr).

Methods as for holotype. Head: dorsally with well-separated longitudinal irregular carinae with scattered cross-carinae, interstices shining; clypeus shining, with longitudinal carinae: one median carina, a sublateral and lateral on each side, right side with a submedian carina, absent on the left side; malar space 1.2 times maximum length of eye; antennae with 12 joints. Mesosoma: pronotum with a few strong carinae forming an irregular network anteriorly, becoming weak and longitudinal posteriorly, interstices shining; mesonotum with dense, longitudinal, slightly irregular carinae, interspaces shining; mesopleuron shining, smooth, with small irregular carinae along dorsal, ventral, posterior borders, transverse mesopleural suture strongly developed, slightly foveolate; propodeum with strong longitudinal carinae, propodeal spines elongate, slender, acute. Petiole in profile with a single, strong, dorsal angle, not truncate, ventrally concave, with a small, sharp angle at anterior border. Postpetiole dorsally minutely roughened, 1.50 times as wide as long. Gaster shining, without sculpture. Pilosity of head and body as in worker. Color: translucent dark yellow, dorsum of head and apex of gaster brown.

Measurements in mm: total length: 4.96; head length: 0.82; head width: 0.77; length of mesosoma: 1.25; length of petiole: 0.37; length of postpetiole: 0.35; length of gaster (segments except first strongly retracted): 1.40.

Male
Males of some North American Temnothorax are unknown or undescribed. Even in the Southeast there are two species, smithi and tuscaloosae, whose males are unknown, at least to us. Male palustris are distinguished from other known southeastern species by the following character states: node of petiole low and rounded, hardly more declivitous posteriorly than anteriorly (unlike texanus, whose declivity is high and abruptly declivitous posteriorly); color black (unlike torrei, curvispinosus, allardycei ); mesonotum not conspicuously bulbous anteriorly and overhanging posterior edge of pronotum (as in pergandei); antennae with a four-segmented antennal club (unlike bradleyi, which has no antennal club; we suspect that smithi, whose workers resemble those of bradleyi in many ways, has similar males); mesonotum lacking the conspicuous parapsidal furrows found in longispinosus. Methods as for holotype. Head: minutely reticulate dorsally, smooth below middle ocellus; faintly sculptured behind ocelli; length of eye 1.10 times the distance between edge of eye and lateral ocellus; antennae with 13 joints, last four conspicuously enlarged to make an elongate club. Mesosoma: pronotum minutely, faintly reticulate, weakly shining; mesonotum without parapsical furrows, roughened with irregular, shallow, longitudinal depressions, irregularly minutely reticulate; midline near anterior border impunctate; mesopleuron shining, smooth except for irregular shallow depressions usually associated with insertions of hairs; metapleuron and propodeum faintly, minutely reticulate, weakly shining. Petiolar node smooth, shining, in profile low and rounded, posterior declivity only slightly steeper than anterior declivity. Postpetiole shining, with a conspicuous submarginal band of irregular shallow depressions and minute reticulations. Gaster smooth, shining. Color: blackish brown; tarsi yellowish white; antennae, mandibles, trochanters, apices of femora light brown; wings, including veins, whitish.

Measurements in mm: total length: 3.27; head length: 0.52; head width: 0.60; length of mesosoma: 0.93; length of petiole: 0.25; length of postpetiole: 0.20; length of gaster: 0.77; length of forewing: 2.20.

Type Material
Holotype: Florida: Liberty Co., Apalachicola Nat’l. For., 14-V-2000, S. Cover & M. Deyrup. 0.4 mi. S. jct. For. Serv. Rds. 107 & 126, 30°12.38’N, 84°45.88’W., elev. under 200’, seasonally flooded shrub marsh. Nest in open, a tiny open hole. Nest chambers less than 2” deep, in root mat on fine white sand. Found by cookie bait. Same data for 71 paratype workers, 1 dealate paratype queen associated with holotype, 3 paratype dealate queens associated with paratype workers, 3 alate paratype queens associated with paratype workers,1 paratype male associated with holotype, 3 paratype males associated with paratype workers.

Holotype, 2 paratype workers from nest of holotype, dealate queen and male from nest of holotype, 9 paratype workers: Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts; 8 workers, one queen, one male: National Museum of Natural History, Smithsonian Institution, Washington, D.C.; 3 workers, one queen, 1 male: Los Angeles County Museum, Los Angeles, California; 7 workers, one queen: Florida State Collection of Arthropods, Gainesville, Florida; 4 workers, one queen: The Natural History Museum, London; remaining type material temporarily in the arthropod collection of the Archbold Biological Station, Lake Placid, Florida.

Etymology
Ecological. palustris, Latin, from palus(feminine) = marsh, and the suffix - tris, = belonging to, or a place where; feminine ending in apposition to palus, not Leptothorax (masculine).

References based on Global Ant Biodiversity Informatics

 * Deyrup, M. and S. Cover. 2004. A new species of the ant genus Leptothorax from Florida, with a key to the Leptothorax of the southeast (Hymenoptera: Formicidae). Floridae Entomologist 87(1):51-59
 * Tschinkel W. R.,T. Murdock, J. R. King and C. Kwapich. 2012. Ant distribution in relation to ground water in north Florida pine flatwoods. Journal of Insect Science 12: 114