Stenamma californicum

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Stenamma californicum
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Stenammini
Genus: Stenamma
Species: S. californicum
Binomial name
Stenamma californicum
Snelling, R.R., 1973

Stenamma californicum casent0005810 profile 1.jpg

Stenamma californicum casent0005810 dorsal 1.jpg

Specimen labels

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.


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.


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

Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).
Neotropical Region: Mexico.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


Oak woodland, chaparral.


Rarely collected.



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




The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

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

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



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.


(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 Los Angeles County Museum of Natural History; one paratype each in American Museum of Natural History, Museum of Comparative Zoology, National Museum of Natural History, ACC, GCW and WSC.


Toponym. Named for the state of California.


  • 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. (page 16, figs. 16, 17, 245, 25, 27 worker, queen described)