Mycetagroicus cerradensis, Brandão & Mayhe-Nunes, 2001

Brandão, C. R. F. & Mayhé-Nunes, A. J., 2001, A new fungus-growing ant genus, Mycetagroicus gen. nov. with the description of three new species and comments on the monophyly of the Attini (Hymenoptera: Formicidae)., Sociobiology 38, pp. 639-665 : 644-647

Mycetagroicus cerradensis new species

Holotype: Worker, BRAZIL. Sao Paulo State: Rancharia [22° 15' S, 50° 55' W), 5. x. 1969, E. Amantc [ MZSP # 6004 Kempfs notebook ], deposited at MZSP .

Paratypes (all from Brazil): 41 workers, same data as holotype (38 MZSP - one prepared for SEM; 3 USNM; 3 CPDC); 4 workers, Distrito Federal: Brasilia [15° 47' S, 47° 55' Wl, Parque Nacional de Brasilia , 13- 14. v. 1971, "cerrado", W. L. & D. E. Brown [col.] (2 MZSP; 2 MCZC); 33 workers, Goias: Faz. Cachoeirinha , Jatai [17° 53' S, 51° 43' W], 20. vii. 1964, Exp. Dep. Zool col. [ MZSP # KL 4264 ] (20 MZSP; 3 CASC; 4 IBUS; 3 LACM; 3 USNM) ; 3 workers, Mato Grosso [today Mato Grosso do Sul ): Fazenda Fortaleza , Paranaiba [19° 40' S, 51° 11" W], 19. ii. 1976. J. L. M. Diniz [ Diniz's field book #951 ] ( MZSP); 3 workers, Minas Gerais: Paraopcba [19° 18' S, 44° 25' W], iii. 1990, J. A. Barcelos [leg.] (2 MZSP; 1 IBUS); 2 workers, Minas Gerais: Lassance [17° 54' S, 44° 34' W], 18. ix. 1985, P. Pacheco col. ( MZSP) ; 5 workers, Parana: Senges [21° 59' S, 48° 23' WJ. 03. xi. 1965, W. Kempf leg. [ MZSP #4154 ] (3 MZSP; 2 IBUS) ; 19workcrs, Sao Paulo: Fazenda Itaquere , Boa EsperancadoSul [21°59' S, 48° 23' W], 20. vii. 1964, K. Lenko leg. [ MZSP # 4472 , Lenko notebook] (10 MZSP- one prepared for SEM; 3 IBUS; 3 INPA; 3 BMNH) ; 6 workers, Sao Paulo: Agudos [22° 28' S, 49° 00' W], 13. xii. 1955, W. Kempf leg. [ MZSP # 1492 ; " Parque do Seminario " Kempf s notebook] (4 MZSP; 2 IBUS) ; 2 workers. Sao Paulo: Botucatu [22° 52' S, 48° 26' W], 11. iv. 1985; 11.x. 1984, M. F. Barros Pcrcira col ( MZSP) .

Etymology. The name refers to the distribution of this species, known only from the Brazilian "ccrrados", a savanna-like formation that once covered most of the Brazilian Central Plateau.

Description. Worker. Measurements (in mm): TL 3.36; HL 0.92; HW 0.92; IFW 0.52; ScL 0.78; TrL 1.34; HfL 1.23. Uniformly brownyellowish to medium brown; gaster darker than the rest of the body in the two Minas Gerais samples; the Paraopeba workers have also the frontal disk of the head darker than the rest of the body. Long and dense pilosity all over the body, hairs mostly erect, but flexuous, little shorter on the appendages than in other regions of the body (Figs 1, 3-5, 7).

Head as in Figs 1-3, 5. Dorsal surface of the mandibles with some 30 rugulae over a straight line perpendicular to the external margin at midlength, ending abruptly at the smooth flange parallel to the masticatory margin (Fig. 5). Masticatory margin with an apical tooth followed by 7-10 minute regularly spaced teeth (Fig. 5), except for the basal one which is separated from the others by a small diastema; the subapical teeth of similar size and triangular in young workers; external margin almost straight at base, weakly concave at apex, curving inwards at the level of the third subapical tooth. Clypeus (Fig. 1-2, 5) with pronounced concave anterolateral projections with rounded apex, at each side, arising near the base of the frontal lobes. Frontal area triangular, depressed but mostly inconspicuous. Frontal lobes subtriangular, the anterior border rounded, crenulated, and almost as long as the straight posterior borders; faces meeting in an attenuated angle of circa 120°. Frontal carinae sinuous, weakly diverging caudad, fading before reaching the occiput. Eyes with 12 facets across its greatest diameter. Antennal scapes surpassing the occipital corners by near one third of their length, when laid back over the head as much as possible. All funicular segments longer than broad.

Alitrunk (Figs 3-4, 6). Lateral pronotal spines triangular when seen from above, projecting laterad when seen in frontal view (Fig. 4). Pair of median projections on pronotum very short or absent; middle of the mesonotum with a low protuberance, better seen in side view, microscopically tuberculated (Fig. 3). Anepisternum separated from katepistcrnum by a strong ridge. Metanotal groove relatively large in side view, shallowly impressed. Propodeal spiracle opening slit-shaped in side view.

Petiole, postpetiole, and gaster (Figs 3, 6-7). Petiole without conspicuous projections; the node proper as seem from above slightly longer than broad, and broader anteriorly (Fig. 6). Postpetiole slightly broader than long in dorsal view. Gaster (Fig. 7) with regularly spaced hair pits, almost in straight parallel lines. The dorsal disk of the gaster marked by two faint widely spaced longitudinal keels.

Biology. Combining information from labels and field notes of Kempf and Lenko, we can say that this species occurs in the "cerrado"' (samples #4151, 4246, and 4472). Although we have no clear information on the collecting sites of most samples, all localities we listed above arc (or were) cerrado areas. Lenko recorded nests as subterranean, with one circular entrance circled by a 3 mm sand crater, surrounded by a 5 cm high mound with 12 cm at base. He has also recorded the workers of sample # 4472 carrying minute plant fragments and very small seeds of grasses and other unspecified items. The Botucatu sample label says "pasture".

Comments. The recognition of Mycetagroicus cerradensis new species is very easy by three main features: the presence of two prominent clypeal concave projections, rounded at apex, the subtriangular frontal lobes, and the absence of the median pronotal teeth.