Temnothorax gallae

An arboreal nesting species that has been found inhabiting cynipid galls on the canyon live oak (Quercus chrysolepis Liebm.) and galls of Andricus spectabilis (Mackay, 2000). It is likely to be found in different types of oak woodland habitats.

Identification
Mackay (2000) - A member of the Temnothorax tricarinatus species complex. The entire dorsum of the head of this species is usually sculptured, with fine costulae mixed with the background punctures and the antenna has 12 segments. The propodeal spines are well developed, longer than the distance between the bases (shorter in smaller workers). The sides of the pronotum are rugose, as well as the top of the mesosoma (can be seen most easily by looking obliquely from the side), but the rugae on the sides of the pronotum are poorly defined and mixed with the background punctuation, and not shiny in the intrarugal surfaces. The rugae are somewhat mixed with the background punctures. The node ofthe petiole is somewhat sharp in profile, the top of the node is coarsely reticulo-rugose, and looks "pinched" or constricted laterally as seen from top, the subpeduncular tooth is well developed. The erect hairs are all blunt and short (about 0.05mm).

This species is similar to chandleri (see discussion of Temnothorax chandleri for details). It is easy to confuse with Temnothorax mariposa (=nitens), due to the shape of the petiole (also sharp in profile, but can be separated by the roughly sculptured head, which is predominantly smooth and shining in Temnothorax mariposa, and by the longer propodeal spines, much longer than space between bases, spines of Temnothorax mariposa about half the length of the distance between the spines). This species could also be confused with Temnothorax nevadensis. It differs in that the propodeal spines are long (nearly twice length of distance between bases), and are slightly incurved at the tips. The petiole has an appearance that it has been pinched from the sides, resulting in the sides of the node being slightly concave in the middle. In comparison, the propodeal spines of Temnothorax nevadensis are about the length of the distance between their bases (or less), but are also slightly incurved. The petiole is usually rounded or somewhat truncate in profile, but is not "pinched" from the sides and the top of the node is convex. This latter species is usually light brown in color. Temnothorax gallae is usually dark brown in color. This species superficially resembles Leptothorax muscorum, but has a well-defined medial carina on the clypeus.

Distribution
USA. California.

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

Habitat
Nests in canyon oaks, in galls, and likely to be found in different types of oak woodland habitats.

Abundance
Not commonly collected.

Other Insects
Smith (1949) reports Temnothorax gallae has been collected from twig galls made on the canyon live oak by the cynipid Heteroecus pacificus(Ashm.), H. sanctaeclarae (Fullaway) and Disholcaspis truckeensis (Ashm.) and Mackay (2000) states they will also nest in galls of Andricus spectabilis.

Plants
Nests in galls on canyon live oak Quercus chrysolepis (Liebm.).

Nomenclature

 *  gallae. Leptothorax (Leptothorax) gallae Smith, M.R. 1949e: 112 (w.) U.S.A. Combination in L. (Myrafant): Smith, D.R. 1979: 1393; in Temnothorax: Bolton, 2003: 271. See also: Mackay, 2000: 346.

Worker
Worker.--Length 3 mm. Head measured through its greatest breadth and length, one and one-seventh times as long as broad, with approximately straight posterior border, rounded posterior corners and weakly convex, somewhat subparallel sides. Eye rather large, located at approximately the middle of the side of the head. Antenna 12-segmented; apex of scape failing by more than its greatest diameter to attain the posterior border of the head; funiculus with a 3-segmented club, which is scarcely longer than the remainder of the funiculus, last segment of the club longer than the combined length of the two preceding segments. Frontal area present but not strongly defined. Middle of the anterior border of the clypeus with a distinct but weak impression or emargination. Mandible 5-toothed. Thorax slender, highest in the vicinity of the junction of the promesonotum, sloping both anteriorly and posteriorly from this region; from above, widest in the pronotum and narrowest at the base of the epinotal spines, with rounded humeri and obsolescent or missing dorsal thoracic sutures, also lacking the mesoepinotal impression. Epinotal spines fairly robust, not strongly divergent, longer than the distance between their bases. Femora and tibia, especially the former, noticeably incrassated. Peduncle of petiole with a small but distinct anteroventral tooth. Petiolar node, in profile, angular, the anterior slope almost straight, the posterior slope shorter and more irregular than the anterior. Postpetiolar node, from above, about one and one-fourth times broader than long, with rounded humeri and subparallel sides, somewhat constricted in the posterior half. Gaster with distinct angles.

Mandibles striate, also punctate. Clypeus with about 7 to 9 prominent carinae, one of them median and the other lateral. Head densely and minutely punctate with the front bearing delicate longitudinal rugulae. Cheeks rugulose or rugulosepunctate. Thoracic dorsum rugulosepunctate, the rugulae most evident on the promesonotum; meso and metapleurae longitudinally rugulose punctate. Petiolar and postpetiolar nodes more minutely rugulosepunctate than the thorax.

Head, thorax, petiole and postpetiole subopaque frontal area and gaster shining. In some lights the head is almost shining.

Body with moderately abundant, coarse, suberect to erect, pale yellowish or grayish hairs; those on the gaster more abundant than elsewhere. Antennae and legs hairless, bearing only appressed pubescence.

Brown; posterior part of gaster and much of head blackish.

Queen
Queens have been collected but this caste is undescribed.

Male
Males have been collected but this caste is undescribed.

Etymology
Descriptive. Named for its propensity to nest in galls.

References based on Global Ant Biodiversity Informatics

 * Des Lauriers J., and D. Ikeda. 2017. The ants (Hymenoptera: Formicidae) of the San Gabriel Mountains of Southern California, USA with an annotated list. In: Reynolds R. E. (Ed.) Desert Studies Symposium. California State University Desert Studies Consortium, 342 pp. Pages 264-277.
 * Mackay W. P. 2000. A review of the New World ants of the subgenus Myrafant, (genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology 36: 265-444.
 * Smith M. R. 1949. A new Leptothorax commonly inhabiting the canyon live oak of California (Hymenoptera: Formicidae). Psyche (Cambridge) 56: 112-115.