Cyphomyrmex rimosus (Spinola)

Snelling, R. R. & Longino, J. T., 1992, Revisionary notes on the fungus-growing ants of the genus Cyphomyrmex, rimosus-group (Hymenoptera: Formicidae: Attini)., Insects of Panama and Mesoamerica: selected studies., Oxford: Oxford University Press, pp. 479-494 : 491

Cyphomyrmex rimosus (Spinola) (Figs 30.9, 30.17, 30.21, 30.2 5)

Cryptocerus? rimosus Spinola , 1 8 5 3:65;

Meranoplus difformis F. Smith , 1858:195;

Cataulacus deformis (sic') Roger, 186 3:2 10. new synonymy.

Cyphomyrmex rimosus : Emery, 189 3: 2. Emery, 1894:224, 225.

Cyphomyrmex rimosus var. fuscus Emery , 1894:225;. new synonymy.

Cyphomyrmex rimosus var. fusculus Emery , 1922:342.

Cyphomyrmex rimosus subsp. curiapensis Weber , 1938:190;;.

Cyphomyrmex rimosus subsp. cochunae Kuszenov , 1949:4 39- 41.. new synonymy.

We have examined the syntypes of C. rimosus , a worker and three males, in the MIZS. Morphologically they are identical to the form described by Emery (1894) as var. fuscus . The worker syntype of C. rimosus , here designated the lectotype, is callow and it is probably for that reason that Emery described normally-coloured workers as var. fuscus . Emery had earlier (1893) examined the syntypes of C. rimosus and so had a clear idea of the appearance of the worker; the var. fuscus was distinguished only by its darker colour.

Cataulacus deformis is usually listed as a synonym of C. minutus . The name is a misspelling of F. Smith's Meranoplus difformis . Roger introduced this variant spelling when he declared that Mayr's minutus was the same as 'deformis'. It is an arguable point, and a trivial one, but we believe that it is most appropriate to maintain the difformis - deformis link.

Weber (1958) established the synonymy of C.r. curiapensis with C. fuscus . Kusnezov's subspecies was described as a simple colour variant. Although we have seen no type material of this form, we find nothing in the original description to suggest that it is anything other than what it appears to be: an insignificant colour form not worthy of formal recognition. Previous records for C. rimosus are from Argentina, Brazil, the Guianas, and Venezuela.

This species has been introduced and is established in the south-eastern United States. We have seen the following specimens: Alabama: Baldwin Co, Gulf State Park, 16 Apr. 1950 (E.O. Wilson; USNM). Mobile Co, Mobile, 6 May 1950 (E.O. Wilson; LACM); Mobile, 26 Jan. 1950 (A. J. Graham; USNM), in abandoned fire ant mound. County unknown, Cottage Hill, 2 Dec. 1949 (J. M. Coarsell; USNM). florida: Alachua Co, near Gainesville airport, 11 Nov. 1981 (J.C. Trager; JCT, LACM), in disturbed flatwood; La Crosse, 1 July 1981 Q.C. Trager; JCT, LACM), in pasture; Archer Road Lab., Gainesville, 16 June 1984 QC. Trager; JCT, LACM), under boards 2 colonies). Highlands Co, Archbold Biological Station. Price Tract, 10 Oct. 1981 (J.C. Trager; JCT, LACM), in rotting branch on ground; Highlands Hammock State Park, 7 Sept. 1981 R.K. Snelling; LACM), in mowed grass area adjacent to forest. Leon Co, Tallahassee, 10 Jan. 1 98 3 G.B. Marshall; LACM), hardwood litter berlesate. Mississippi: Harrison Co, IO miles N. Gulfport, Nov. 1957 H.T. Yanderford; USNM; Lyman, 24 Mar. 1 9 70 (C. H. Craig; USNM), ex fire ant mound..Mates have been taken within nests between 6 May and 1 July.

In addition to the differences cited in the above key, workers of C. rimosus may be further differentiated from those of C. minutus by the more prominent dorsal mesosomal tubercles; in particular, the anterior mesonotai tubercle is bluntly triangular in C. rimosus , rather than very low and obtuse as in C. minutus . In C. rimosus the metafemur is sometimes angulate at the basal one-third of the ventral surface, but often it is broadly rounded, and there is, at most, a very weak ridge extended distally from the angulation. The metafemur is distinctly angulate in C. minutus and an often lamella-like carina extends distally from the angulation.

Females of the two species differ in many of the same features as do their workers, except, of course, those of mesosomal contour. The head width of C. rimosus females is 0.75 mm or more; that of C. minutus is less than 0.70 mm, usually about 0.67mm. Males of C. rimosus are a little larger than those of C. minutus (head width, across eyes, 0.73 vs. 0.68 mm), the lateral ocelli are elevated, the occipital tubercle is bluntly spinelike, and the propodeal teeth, although short, are definitely spine-like.

The following biological information has been provided by J.C. Trager for two samples collected 16 June, 1984 in Gainesville:

These ... were under boards in a weedy lot next to my lab. The brood and fungus gardens of the colonies were kept apart but adjacent on grass stolons or compacted grass blades near the center of single nearly round 5-8 cm-diam. chambers, 1-2 cm deep. Males were clustered on the underside of the board (the warmest, driest part of the nest). The insect fragments, grasshopper feces, etc. collected with one series were heaped separately at opposite sides of the periphery of the nest chamber. This rigid compartmentalization of castes and materials is typical of... this ant. [Queens are usually] associated with the brood [and] most often there are 1 or 2 queens per nest, but I've seen 3 or 4 on occasion. Mating flights take place at the first faint light of dawn, following heavy rains alter a dry spell during the summer months.