Stenamma heathi

This species is known from a few collections. The only information beyond what is given in the description, and subsequent revision, comes from a litter sifting sample by Phil Ward (casent0005815): collected from leaf litter in a Sequoiadendron grove.

Identification
This is one of the more distinctive western Stenamma, most readily recognized by the peculiar sculpturation of the first tergite. Very nearly the entire segment is shagreened and finely, densely punctulate. Over the basal third of the segment extend a variable number of fine longitudinal rugulae which tend to form a reticulate pattern in some specimens. Finally, scattered over the entire segment are numerous coarse punctures, from each of which arises a long, coarse hair. The overall effect is very peculiar and is shared, in North American species, only with Stenamma exasperatum. Other western species, such as Stenamma californicum, Stenamma dyscheres and Stenamma punctatoventre have sculptured first tergites, but in these species the sculpturation consists of fine, dense punctulation and is restricted to the basal third, or less; fine longitudinal basal striae may be present or not. These species wholly lack the conspicuous coarse, piligerous punctures. (Snelling 1973)

Distribution
Mexico and USA. Smith 1957: California and Nevada. In addition to the type locality this species is known from the Yosemite and Sequoia National Parks of California and from Washoe County, Nevada. As reported in Snelling 1973: Sierra San Pedro Martir, Baja California, Mexico (col. W.S. Creighton).

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

Nomenclature

 *  heathi. Stenamma brevicorne subsp. heathi Wheeler, W.M. 1915b: 410 (w.) U.S.A. Snelling, R.R. 1973c: 31 (q.). Raised to species: Creighton, 1950a: 137. See also: Smith, M.R. 1957b: 154.

Worker
Smith (1957) - Length 2.5-3.3 mm. Second to 6th funicular segments broader than long, the last funicular segment almost as long as the combined lengths of the three preceding segments. Eye subelliptical, approximately 0.10 mm in its greatest diameter which contains from four to six ommatidia. Thorax, in profile, with variable sized mesoepinotal impression which is sometimes well pronounced and approximately twice as long as deep. Base of epinotum distinctly sloping posteriorly. Epinotal spines well developed, slender, with acute apices, approximately 0.25 to 0.33 the length of the base of the epinotum. Petiolar node, in profile, angular; from above and behind, varying from subrectangular to subconical, with truncate or weakly emarginate superior border. Postpetiolar node, from above and behind, as broad as long or broader than long, with subparallel sides except in the anterior third or fourth where the sides converge anteriorly.

Much of the head reticulate-punctate but the sculpturing not always easily seen because of the color of the head. Frontal striae present but also not always clearly discernible. Thorax above coarsely and rather irregularly reticulate, many of the interspaces often quite broad; rugulae on the anterior portion of the prothorax quite often transverse and the rugulae on the promesonotum frequently with a longitudinal trend. Petiolar node rugulose-punctate to rugulose-reticulate, punctate; dorsal surface of postpetiolar node similarly sculptured. Longitudinal rugulae at the base of the gaster not as long and prominent as in sequoiarum. Much of the first gastric segment with a shagreening and scattered punctures which gives this region a subopaque effect, especially in certain lights. Frontal area, clypeal furrow, epinotal declivity and gaster, except at noted, smooth and shining.

Hairs light yellowish or grayish, moderately abundant, but not obscuring the ground surface of the body; apparently most abundant on the gaster.

Body and appendages varying from yellowish brown or light reddish brown to dark reddish brown; the gaster usually scarcely darker than the remainder of the body.

The most notable variations in the worker are: The proportions of the head; the number and shape of the teeth on the mandible; the number of ommatidia in the greatest diameter of the eye, this ranging from about 4-6; the mesoepinotal impression often pronounced, about twice as long as deep but occasionally smaller and less well defined; petiolar node when viewed from above and behind commonly subrectangular but occasionally subconical; postpetiolar node from about as broad as long to broader than long; sculpturing on the thorax highly variable as is also the color of the body. The single Nevada worker is dark reddish brown with a blackish, first gastric segment; this segment is also more opaque than ordinarily because of the nature of the sculpturing.

Type Material
Smith (1957) - Kings River Canyon (Fresno County), California. Described by W. M. Wheeler from 25 workers taken from a single colony by Professor Harold Heath. American Museum of Natural History, Museum of Comparative Zoology at Harvard College, U. S. National Museum.

Etymology
Patronym. The type specimens were collected by Professor Harold Heath.

Additional References

 * Snelling, R. R. 1973. Studies on California ants. 7. The genus Stenamma (Hymenoptera: Formicidae). Contributions in Science (Los Angeles). 245:1-38.
 * Wheeler, W. M. 1915. Some additions to the North American ant-fauna. Bulletin of the American Museum of Natural History. 34:389-421.