Stenamma californicum

Very Little is know about this species. The types were found in fern humus and a second collection is noted as being from the leaf litter in chaparral. Other collections have been taken in oak woodlands.

Identification
A relatively small and variable species in the diecki group. Eyes with 3-5 facets in greatest diameter; thoracic rugulae coarse, close, interspaces moderately to strongly shiny; postpetiole shiny between rugulae; first tergite lightly punctulate on basal third or less; first sternite punctulate and firiely striolate, at least at sides. The sculptured first sternite, within this group, is shared with Stenamma dyscheres, but that species is usually larger, has distinct, rather coarse rugulae on the sides of the thorax, usually has distinct longitudinal striae on the first sternite and the first tergite is not distinctly punctulate.

Workers are uniformly light ferruginous with the sutures and margins a little darker.

Distribution
USA and Mexico. Known from California, Arizona and Baja California.

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

Habitat
Oak woodland, chaparral.

Abundance
Rarely collected.

Castes
Snelling (1973) reports there are ten males known from a collection of a mating flight from the Berkeley Hills. There is no taxonomic description of Stenamma californicum males.

Nomenclature

 *  californicum. Stenamma californicum Snelling, R.R. 1973c: 16, figs. 16, 17, 24, 25, 27 (w.q.) U.S.A.

Worker
Measurements. HL 0.63-0.83 (0.76); HW 0.53-0.70 (0.63); SL 0.53-0.60 (0.60); WL 0.76-1.00 (0.93); PW 0.36-0.46 (0.43).

Head. A little longer than broad, CI 77-85 (82), longer than scape; slightly narrowed toward occiput. Eyes small, with 3-5 facets in greatest diameter, OMD 2.9-3.6 (3.0) x EL; OI 7.7-9.5 (8.7). Scape rather stout, shorter than to equal to HW, SI 85-100 (98), ending below level of occipital margin, cylindrical at base, distinctly thicker apically than near base. Mandible with five large, equally spaced teeth, one or two minute denticles sometimes present. Mandible shiny, striate on basal half, coarsely and closely punctate apically. Clypeus shiny; median lobe longitudinally depressed, laterally carinulate, appearing notched in frontal view; in profile, median lobe short, oblique, extending below antennal socket by about maximum eye length. Depressed frontal area shiny; frontal lobes shiny; remainder of head densely punctulate and dull or slightly shiny, irregularly finely rugulose, forming reticulae on sides and occiput.

Thorax. Pronotal neck dull, densely punctulate, with one or two fine transverse rugulae on vertical surface; sides moderately shiny, lightly punctulate, with a few widely spaced, irregular longitudinal rugulae; dorsum slightly shiny, densely punctulate, with distinct median longitudinal rugulae and short irregular rugulae laterad. Mesonotum dull, densely punctulate, reticulo-rugose. Mesopleura densely punctate and dull, with a few short, irregular longitudinal rugulae. Metanotal depression broad, shallow, poorly defined. Propodeal base slightly shiny, densely punctulate, with a pair of rugulae extending from middle of base to bases of spines, otherwise without prominent rugulae; sides with prominent longitudinal rugulae, interspaces slightly shiny and densely punctulate; spines variable, from corners largely angulate to having short, distinct spines, distance between spines at least twice length of spines; deciivitous face distinctly shiny, lightly punctulate.

Petiole. Anterior peduncle thick in profile, dorsal face slightly shorter than anterior face of node; node broadly triangular in profile, summit narrowly rounded; triangular ventral projection present, or not, anteriorly. Postpetiole, from above with sides slightly convex, about as broad as long; ventrally with distinct anterior projection. Sides of petiole and postpetiole dull, densely punctulate, nodes slightly to moderately shiny, without prominent rugulae.

Gaster. First tergite lightly punctulate over basal half or less and moderately shiny, apical half more lightly punctulate to nearly smooth, shinier than basal half but not polished. First sternite variable but always densely punctulate over basal half or more of sides, often most of disc densely punctulate and slightly shiny.

Pilosity. As usual in the genus, with numerous fully erect hairs on most body surfaces, clypeal and frontal hairs longest, those of frons short, uniform in length, rather sparse.

Color. Uniformly light ferruginous, sutures and margins a little darker.

Queen
(dealate). Measurements. HL 0.83; HW 0.75; SL 0.61; WL 1.23; PW 0.63.

Similar to worker except for usual sexual modifications. Head a little broader, CI 90; eyes about 0.23 mm long, OMD 0.71 x EL; OI 28; distance between posterior ocelli about equal to distance between anterior ocellus and posterior ocelli, the latter about 3 times diameter of anterior ocellus. Scape a little short of occipital margin; SI 82. Head more coarsely and distinctly reticulate. Metapleura mostly smooth and shiny, with a few fine longitudinal rugulae above and posteriorly with a few coarser short rugulae, the interspaces densely punctulate. Gaster much as in worker.

Type Material
Snow Creek Canyon, San Jacinto Mts., Riverside Co., CALIF., 20 March 1954 (J. N. Belkin, et al.) in fern humus. Holotype and 14 paratype workers: Holotype and 8 paratypes in ; one paratype each in, , , ACC, GCW and WSC.

Etymology
Toponym. Named for the state of California.

References based on Global Ant Biodiversity Informatics

 * Adams T. A., W. J. Staubus, and W. M. Meyer. 2018. Fire impacts on ant assemblages in California sage scrub. Southwestern Entomologist 43(2): 323-334.
 * Boulton A. M., Davies K. F. and Ward P. S. 2005. Species richness, abundance, and composition of ground-dwelling ants in northern California grasslands: role of plants, soil, and grazing. Environmental Entomology 34: 96-104
 * Cover S. P., and R. A. Johnson. 20011. Checklist of Arizona Ants. Downloaded on January 7th at http://www.asu.edu/clas/sirgtools/AZants-2011%20updatev2.pdf
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * 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.
 * Holway D.A. 1998. Effect of Argentine ant invasions on ground-dwelling arthropods in northern California riparian woodlands. Oecologia. 116: 252-258
 * Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
 * Johnson, R.A. and P.S. Ward. 2002. Biogeography and endemism of ants (Hymenoptera: Formicidae) in Baja California, Mexico: a first overview. Journal of Biogeography 29:10091026/
 * Snelling R. R. 1973. Studies on California ants. 7. The genus Stenamma (Hymenoptera: Formicidae). Contributions in Science (Los Angeles) 245: 1-38.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Ward P. S. 1987. Distribution of the introduced Argentine ant (Iridomyrmex humilis) in natural habitats of the lower Sacramento Valley and its effects on the indigenous ant fauna. Hilgardia 55: 1-16