Taxonomic History (provided by Barry Bolton, 2014)
Cyphomyrmex rimosus is a small dull brown to blackish brown ant with deep antennal scrobes, enlarged frontal lobes that obscure the lateral margins of the face, no propodeal spines, an apedunculate petiole, tubercles on the mesosoma, and appressed scale-like hairs. These ants are sometimes difficult to detect on account of their small size, slow movement and tendency to become immobile and even feign death when disturbed. Cyphomyrmex rimosus has a monomorphic worker caste and is considered one of the ‘lower’ attines and cultivates fungus gardens grown on scavenged vegetable matter, dead insects and insect fras. The species is native to the Neotropics, but has established introduced populations in the southern United States and the Galapagos islands. It is not considered a significant pest species in its native or introduced range.
Native Range (Snelling & Longino, 1992). Neotropics. Argentina, Brazil, Guinanas, Venezuala.
Introduced Range. Galapagos: Isabella, Santa Cruz. United States (Snelling & Longino, 1992): Alabama, Florida, Georgia, Mississippi.
The species is part of a complex of closely related and highly variable taxa that can be difficult to distinguish (Kempf, 1966 (1965)). Snelling and Longino (1992)revised the C. rimosus group and split it into five subgroups. The rimosus subgroup contains seven species, including C. rimosus and its close relative C. minutus. Both species occur in Florida, but whereas C. rimosus is argued to be introduced on the grounds that it has spread rapidly since it was first detected, Cyphomyrmex minutus is considered native (Deyrup, 1991). Cyphomyrmex minutus was treated as a junior synonym of C. rimosus prior to the revision of Snelling and Longino (1992), so it is difficult to determine which species earlier studies are referring to. For example, many of the Neotropical and North American records in the literature refer to the more widespread C. minutus (Snelling & Longino, 1992).
Cyphomyrmex rimosus usually live in colonies of less than 100 workers, but colonies of over 300 workers have been observed (Murakami & Higashi, 1997). Most colonies are usually monogynous, but there are reports of some polygynous colonies as well (Murakami & Higashi, 1997; Snelling & Longino, 1992). The fungus gardens are composed of yeasts in the unicellular phase rather than in the multicellular, mycelial phase typical of all other attine gardens (Mehdiabadi & Schultz, 2010). In addition to feeding on the yeast fungus grown in their gardens, C. rimosus is also known to take the nectar and sap of plants (Murakami & Higashi, 1997). The queens are reported to practice monandry and semi-claustral nest founding (Mehdiabadi & Schultz, 2010; Tschinkel, 1987). Nests are frequently simple, shallow, impermanent structures under rocks, logs or any other surface, and the species prefers open habitats. Further details of the natural history of C. rimosus, in is given in Mehdiabadi & Schultz (2010), Murakami & Higashi (1997)and Snelling and Longino (1992).
(Source unkown). Anida en raíces de las plantas, bajo piedras, forrajea entre la hojarasca. Es frecuente en áreas ocupadas por Wasmannia auropunctata. Presente en jardines de las viviendas y sitios húmedos.
English translation: Nests in plant roots, under rocks, foraging among the fallen leaves. It is common in areas occupied by Wasmannia auropunctata. Present in gardens of dwellings and wet locations.
Diagnosis among workers of introduced and commonly intercepted ants in the United States. Antenna 11-segmented. Antennal club 2-segmented. Antennal scapes easily extended beyond eye level. Antennal scrobe present and well developed. Eyes medium to large (greater than 5 facets) but distinctly less than half head length. Eyes located below antennal scrobe near midline of head. Frontal lobes obscure face outline between mandible and eye. Posterolateral corners of head unarmed, without spines. Mandibles triangular. Pronotal spines absent. Propodeum lacking spines or teeth, but tubercles are present. Waist 2-segmented. Spongiform not attached to any portion of waist. Dull brown to blackish brown. Surfaces with appressed scale-like hairs.
In the United States, C. rimosus is most likely confused with C. minutus. Snelling and Longino (1992) separate the two species by the following characters. The head width of C. rimosus is greater (0.62 mm vs. 0.56 mm), and in C. rimosus the hairs on first gastral tergite are not completely appressed and separated by less than their own lengths whereas those of C. minutus are closely appressed and usually separated by more than their own lengths.
Among other introduced and commonly intercepted ants in the United States, C. rimosus can be distinguished the enlarged frontal lobes that obscure the lateral margins of the face, 11-segmented antenna, deep antennal scrobes, indistinct antennal club, and lack of propodeal spines. The antennal scrobes and lack of spines separates C. rimosus from other attine genera (Acromyrmex and Atta). Cephalotes species also have enlarged frontal lobes that obscure the lateral face margins, but C. rimosus can be distinguished from them by the eyes which are placed below antennal scrobe near midline of head (as opposed to at or near apex of antennal scrobe in Cephalotes).
Deyrup, M. (1991) Exotic ants of the Florida keys (Hymenoptera: Formicidae). In: Eshbaugh, W.H. (Ed.) Proceedings of the 4th symposium on the natural history of the Bahamas. Bahamian Field Station, San Salvador, Bahamas, pp. 15-22.
Deyrup, M. (2003) An updated list of Florida ants (Hymenoptera: Formicidae). Florida Entomol., 86, 43-48.
Deyrup, M., Davis, L. & Cover, S. (2000) Exotic ants in Florida. Trans. Am. Entomol. Soc., 126, 293-326.
Kempf, W.W. (1966 (1965)) A revision of the Neotropical fungus-growing ants of the genus Cyphomyrmex Mayr. Part II: Group of rimosus (Spinola) (Hym., Formicidae). Stud. Entomol., 8, 161-200.
Mehdiabadi, N.J. & Schultz, R. (2010) Natural history and phylogeny of the fungus-farming ants (Hymenoptera: Formicidae: Myrmicinae: Attini). Myrmecol. News, 13, 37-55.
Murakami, T. & Higashi, S. (1997) Social organization in two primitive attine ants, Cyphomyrmex rimosus and Myrmicocrypta ednaella, with reference to their fungus substrates and food sources. J. Ethol., 15, 17-25.
Snelling, R.R. & Longino, J.T. (1992) Revisionary notes on the fungus-growing ants of the genus Cyphomyrmex rimosus group (Hymenoptera: Formicidae: Attini). In: Quintero, D. & Aiello, A. (Eds.) Insects of Panama and Mesoamerica: selected studies. Oxford University Press, Oxford. xxii + 692 p., pp. 479-494, English summary p. 653, Spanish summary p. 662-663.
Tschinkel, W.R. (1987) Relationship between ovariole number and spermathecal sperm count in ant queens: a new allometry. Ann. Entomol. Soc. Am., 80, 208-211.
Taxon Page Author History
On 2012-07-11 15:31:42 Eli Sarnat modified References
On 2012-07-11 15:30:43 Eli Sarnat modified Identification
On 2012-07-11 15:30:30 Eli Sarnat modified Identification
On 2012-07-11 15:29:33 Eli Sarnat modified Biology
On 2012-07-11 15:17:41 Eli Sarnat modified Distribution
On 2012-07-11 15:16:39 Eli Sarnat modified Overview
On 2011-03-31 23:46:13 Eli Sarnat modified Distribution
On 2011-03-31 23:46:13 Eli Sarnat modified Biology
Taxonomic Treatment (provided by Plazi)
Forel, A., 1893:
(No. 50 a a 50 r). [[ worker ]] [[ queen ]] [[ male ]].
(50). Common, in open or shady ground. Communities of four or live to twenty - rarely larger - to one hundred individuals. The formicarium is a simple cavity under a stone or stick, at the roots of grass, or occasionally in rotten wood. The ants are very sluggish, hardly moving when disturbed. I have not found the workers in beating foliage, and judge that they are nocturnal, and probably terrestrial, in their habits. I have perhaps included more than one species under this number. Those found in a nest are always of. the same colour, or nearly so; and, though the colour may be due to age, it is singular that there should be no variation in a community. There seem also to be differences of size and form; but my object in separating the species is simply to get better notes on them, and of course the work is very roughly done. I have found these ants crawling, towards evening, on the floor of a dark outhouse. They move slowly.
(50 a). Wallilobo (leeward), Nov. 8 th. Open valley near sea-level. Nest under the edge of a stone; an unusually large community. Many grass-seeds were found in the nest.
(50 b). Bowwood Valley, near Kingstown, 800 ft. Open place under stone. Oct. 2 lst.
(50 c). Near Palmyra Estate (leeward), 1000 ft. Nov. 4 th. Shady place near stream; under turf on a rock. A small community. All I could find are in the bottle.
(50 d). Richmond Valley, 1000 ft. Nov. 13 th. Shady banks of stream; under turf on a rock.
(50 e). Wallilobo Valley (leeward), 500 ft. Nov. 8 th. Under sod on a rock.
(50 f). Golden Grove (leeward); open place, 300 ft. Oct. 10 th. Small nest (ten or twelve ants) under a stone ..
(50 g). Forest above Chateaubelais (leeward), 1000 ft. Oct. 11 th. Under a stick.
(50 h). Old Botanical Garden, Kingstown, 500 ft. Oct. 22 nd. Under bark of rotten log.
(50 i). Wallibou (leeward); seaside thickets. Oct. 8 th. From two or three small nests under stones.
(50 j). Near Palmyra Estate (leeward), 1000 ft. Nov. 4 th. Shady banks of stream. Small nest under sod on a rock.
(50 k). Near Cumberland (leeward); open valley, 200 ft. Oct. 10 th. Small nest under a stone.
(501). Various localities. Specimens from different nests.
• (50 m). Petit Bordelle Valley, 1200 ft. Nov. 12 th. Shady banks of stream; under sod on a rock.
(50 n). Brighton Estate, southern end of island. Nov. 17 th. Open place, 500 ft.; under sod on a rock. A community of about a hundred individuals.
(50 o). Hermitage Estate, Cumberland Valley, 1000 ft. Dec. 2 nd. Small nest tinder dry sod on a rock; edge of forest.
(50 p). Windward side, Grand Sable Estate. Jan. 3 rd. Thicket near seashore; side of a rock under earth. A community of about forty workers, with a good many males and females.
(50 q). Windward side; sandy bed of the Dry River; near the sea; ' open land. Jan. 2 nd. Under a stone,
(50 r). Richmond Valley; thick forest, 1100 ft. Dec. 29 th. Male found under rotting leaves, & c.
Kempf, W. W., 1966:
Cyphomyrmex rimosus , presently taken as a polytypical species, is both the commonest form in the genus and at the same time a residue of classification. The puzzling variability of the complex, which gave rise to a number of infraspecific names in the past, needs a special study, not possible at this time.
Yet I must point out that the infraspecific arrangement for rimosus , as proposed at the beginning of this paper, does not imply a judgement upon the validity of the actually recognized 11 morphs and 6 synonyms. It only serves the purpose of keeping track of these names.
The separation of hamulatus , salvini and transversus as full species, and the return of cochunae and venezuelensis to the rimosus complex are novelties. The former step, i. e. the raising of the three "races" to specific category seems to be justified by morphological and distributional considerations; cochunae , elevated to species level by Kusnezov (1957) does not deserve this rank being probably just a synonym of one of the previously described morphs of rimosus ; venezuelensis did not prove a synonym of transversus , as proposed by Weber (1958), and was put back under rimosus awaiting clarification of its true status.
Snelling, R. R., 1992:
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.
Wild, A. L., 2007:
Alto Paraná , Caaguazú (MZSP). Literature records: Canindeyú , “Paraguay” (s. loc.) (Emery 1894a, Fowler 1981).
Kempf, W. W., 1968:
Dr. Weber did not fail in discovering a flaw in my grouping. The rimosus-group, which I already set up in 1962, did not quite live up to expectations. As a matter of fact, longiscapus and to a lesser degree also wheeleri , costatus and possible allies, do not completely conform to the group definition. While definitely distinct from the strictly homogeneous strigatus-group, they might be set apart as a third group within the genus. This situation has already been recognized in the second part of my Cyphomyrmex revision (Kempf, 1965: 163, 166-7).
Specimen Habitat Summary
Found most commonly in these habitats: 2 times found in Tropical hardwood forest, 1 times found in in cypress and pine swamp, 1 times found in Zona litoral, 1 times found in Hammock, 1 times found in Moist tropical forest, 1 times found in pine-oak forest, transitional to hardwood swamp forest, 1 times found in Port of entry, 1 times found in PPBio Grid, L-O 01
Collected most commonly using these methods or in the following microhabitats: 1 times under rock, 2 times sifting leaf litter, 1 times Colecta manual; cultivando hongos en bordillo de cemento (jardín), 1 times hand collected, 1 times Pitfall trap, 1 times FIT, 1 times Gallery on fallen tree with termites, 1 times Garden, 1 times In soil, 1 times Log stage 3, 1 times Pitfall 09, ...
Elevations: collected from 5 - 1067 meters, 355 meters average
Type specimens: syntype of Cyphomyrmex rimosus: casent0904979, casent0909377; syntype of Cyphomyrmex rimosus curiapensis: casent0901677; syntype of Meranoplus difformis: casent0901675
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