Tapinoma schreiberi

The types were found in a pine-fir forest.

Identification
Hamm (2010) - This species is superficially similar to Tapinoma sessile, but this bicolored ant can be distinguished from the latter by its head and mesosoma (which are rufous) and its gaster (which is black). The workers and queens are, on average, larger than T. sessile, although males seem smaller and are concolorous. The comparisons in size between the sexual castes of T. sessile and T. schreiberi  are made using very low numbers of individuals; caution should be exercised when using these data. I do not believe that this species is the Tapinoma dimmocki of Fisher and Cover (2007) because workers of both species are aggressive toward one another and were never found in the same nest.

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

Nomenclature

 *  schreiberi. Tapinoma schreiberi Hamm, 2010: 25, figs. 5-8 (w.q.m.) U.S.A.

Worker
Holotype. HL, 0.82 mm; HW, 0.84 mm; SL, 0.82 mm; EL, 0.20 mm; MFC, 0.32 mm; EW, 0.16 mm; FL, 0.76 mm; LHL, 0.70 mm; PW, 0.60 mm; ES, 3.2 mm; SI, 100; and CI, 102.44.

Appearance is superficially similar to Tapinoma sessile, although generally larger. The following mean values (± SD) of measurements were the made from 148 workers: HL, 0.77 ± 0.06 mm; HW, 0.75 ± 0.07 mm; SL, 0.77 ± 0.08 mm; EL, 0.19 ± 0.02 mm; MFC, 0.29 ± 0.03 mm; EW, 0.15 ± 0.01 mm; FL, 0.69 ± 0.05 mm; LHL, 0.63 ± 0.05 mm; PW, 0.54 ± 0.06 mm; ES, 2.75 ± 0.41 mm; SI, 99.50 ± 7.02; and CI, 95.80 ± 7.29. The worker is bicolored with the head and mesosoma rufous in color; the gaster is black to brown, although in older workers this color fades to gray. The head is concave at the vertex and ocelli are absent. The antennal scape surpasses the vertex by approximately one third its total length; the flagellum possesses 12 segments. The anteroclypeal margin has a shallow concavity that does not surpass the antennal sockets. The mandibles with four teeth and seven denticles with the apical tooth the longest, slightly larger than the subapical tooth, the basal angle is not distinct and the curve between the masticatory and basal margin is smooth and not interrupted. In total, six anterior clypeal setae overhang the mandibles. Erect hairs are absent on the dorsum of the mesosoma though are present on propleuron, coxae and gastral sternites, and posterior tergites.

Queen
Mean values (± SD). Four alate queens. LACM: HL, 0.93 ± 0.03 mm; HW, 1.03 ± 0.02 mm; SL, 0.87 ± 0.02 mm; EL, 0.26 ± 0.01 mm; MFC, 0.41 ± 0.02 mm; EW, 0.2 ± 0.02 mm; FL, 0.84 ± 0.02 mm; LHL, 0.74 ± 0.04 mm; PW, 1.04 ± 0.0.03 mm; WL, 1.23 ± 0.04 mm; WGL, 4.08 ± 0.22 mm; ES, 5.20 ± 0.42 mm; SI, 93.60 ± 1.63; and CI, 110 ± 1.28. The queen is bicolored with the head and mesosoma rufous in color; the gaster is black to brown, although in older workers this color fades to gray. The head is slightly concave at the vertex and three ocelli are present. The antennal scape surpasses the vertex by approximately one third its total length; the flagellum possesses 12 segments. The anteroclypeal margin has a shallow concavity that does not surpass the antennal sockets. The mandibles with seven teeth and seven denticles with the apical and subapical teeth the longest, the basal angle is not distinct and the curve between the masticatory and basal margins is smooth and not interrupted. A total of six anterior clypeal setae overhang the mandibles. Erect hairs are absent on the mesosoma and gaster. The queens of this species seem slightly larger than T. sessile queens.

Male
Mean values (± SD). LACM: HL, 0.68 ± 0.06 mm; HW, 0.68 ± 0.01 mm; SL, 0.73 ± 0.01 mm; EL, 0.26 ± 0.01 mm; MFC, 0.20 ± 0.03 mm; EW, 0.21 ± 0.01 mm; FL, 0.75 ± 0.01 mm; LHL, 0.64 ± 0.01 mm; PW, 0.76 ± 0.01 mm; MML, 1.08 ± 0.03 mm; WGL, 3.1 ± 0.31 mm; ES, 5.46 ± 0.37 mm; SI, 107 ± 2.39; and CI, 100 ± 4.16. The vertex of the head is flat to slightly convex, three ocelli at the vertex. Antennae with 13 segments, the scape surpasses the vertex of the head by one half its length. Apical tooth longest, masticatory margin of mandible with a series of small denticles. The male is concolorous and rufous or piceous brown, and is thus very similar to T. sessile, though generally smaller.

Type Material
Holotype. Worker, collected by P. S. Ward and deposited in the at Harvard University, bearing the following labels: “CA Nevada Co. Sagehen Creek 39_ 26N, 120_ 14W 1,920 m, 27-VI-1994 PS Ward # 12585” “grd. forager(s) pine-fir forest.” This specimen also will carry a label designating it as the holotype. Additional material from this series of collected workers resides at the and.

Etymology
The species is named in honor of Dr. Fred Schreiber, a professor for > 35 yr at California State University Fresno and mentor to countless students.

References based on Global Ant Biodiversity Informatics

 * Hamm C. A. 2010. Multivariate discrimination and description of a new species of Tapinoma from the western United States. Annals of the Entomological Society of America 103: 20-29