Further Revisionary Studies On The Ant Genus Megalomyrmex Forel (Hymenoptera: Formicidae: Myrmicinae: Solenopsidini) C R F. B Abstract Author Brandão, Carlos Roberto F. Museu de Zoologia da Universidade de São Paulo - Av. Nazaré, 481 - CEP 04263 - 000, São Paulo, SP, Brasil. E-mail: crfbrand @ usp. br text Papéis Avulsos de Zoologia 2003 São Paulo 2003-12-31 43 8 145 159 http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0031-10492003000800001&lng=en&nrm=iso&tlng=en journal article 10.1590/S0031-10492003000800001 1807-0205 12640541 Megalomyrmex foreli Emery, 1890 Megalomyrmex foreli Emery, 1890:46-47 , pl. 5, fig. 3, worker. Type Locality: Jimenez, Limón , Costa Rica ( 10°13’N , 83°43’W ). Forel, 1899:57-58 , male. Megalomyrmex latreillei Emery, 1890:47 , pl. 5, fig. 4, worker. Type Locality: probably San Antonio de Cumbasa (see Brandão, 1990 ), San Martin , Peru ( 06°21’N , 76°19’W ). Brandão, 1990:436 , male. Nov. Syn. I. Zelner-Polania sent me for study three samples of Megalomyrmex of the Leoninus group from localities in Colombia that fill the gap in the known distribution of M. foreli and M. latreillei . These are: one worker from Caño La Curia, 580 m , Reserva Nacional La Macarena ( 02°45’S , 73°55’W ), Meta province , collected by F. Fernández, two workers collected at the banks of Rio Guayuriba, Meta province , by Richter in December, 1950 to January, 1951, 500-700 m ( 03°55’S , 73°05’W ), and six workers from Doncello, collected by Zelner-Polania in February, 1991. These samples are intermediate in all characters I thought could separate M. foreli from M. latreillei , including color pattern; therefore, I propose the synonymy of the former un- der M. foreli . The resulting taxon is very variable in character states otherwise constant in the genus, as the postpetiolar ventral process that, in certain localities (particularly in Colombia ), can be strongly produced into a long and thin spine, lacking or completely worn out in specimens from other places, although the anteroventral margin of the postpetiole in this case is always sharp. This process wears out with age, leaving only a scar. In these specimens, the gasters are concolorous with the rest of the body. The gaster is often darker in this species. Specimens from Costa Rica and Ecuador (limits of the known species distribution) are lighter in color than those from Colombia and Brazil ( Acre ). From IHVL , I received two samples of M. foreli from Caquetá , Colombia : two workers from San José del Fragua , R . Turayaco , 1000 m , collected in tuna baits in September 1 to 8, 2000 by E.L.G., and four workers from Parque Nacional Picachua ( 02°47’51”S , 74°61’18”W), 1500 m collected manually by F. Escobar and E. Gonzales (no. 5), in November 18, 1997 . I examined also a worker of M. foreli collected by L.A. T . de Alonso ( LET # 828 ) with ground tuna bait in primary forest in Jatun Sacha , Napo Province in Ecuador in January 26, 1994 , and two workers collected by J. Longino , in February , 26, 1981 in Rio Niño ( 300 m ) ( 08°31’S , 83°38’W ), Osa Peninsula , Corcovado , Costa Rica . From J. Delabie I received a worker ( CEPLAC # 991) collected in Darien , Cerro Pirre, Panama , in August 26 to 30, 1991 by R . Ruiz. It is clearly a member of the Leoninus group. Megalomyrmex foreli is the only species in the Leoninus group that probably occurs in Panama , although I have samples only from Costa Rica and Colombia and not from Panama itself. This particular specimen, although too small in relation to all other samples of M. foreli studied so far, shows the color pattern of the Costa Rican samples of M. foreli , but lacks an anteroventral process of the postpetiole. As I have seen only one specimen , I refrain to describe it as a new species for the time being, hoping to study more material of the Leoninus group from Panama . Jones et al. (1999) studied the venom alkaloids of M. foreli (= M. latreillei ) workers collected in Garza Cocha-Añyagu, 175 km eastern of Coca, Provincia de Sucumbios Ecuador in August 12,199 4. I have not studied this material. The locality record “Colombiana Farm” in Brandão (1990) is in the Alajuela province , and not in Santa Clara, as stated.