Mycetarotes senticosus, Kempf, W. W., 1960

Kempf, W. W., 1960, A review of the ant genus Mycetarotes Emery (Hymenoptera, Formicidae)., Revista Brasileira de Biologia 20, pp. 277-283 : 282-283

Mycetarotes senticosus sp. n.

(Figs. 4-6)

Worker (holotype) - Total length 3,7 (3,7-4,0) mm; maximum length of head capsule 0,94 (0,94-0,98) mm; maximum width of head including eyes 0,87 (0,87-0,92) mm; length of scape 0,91 (0,91-0,94) mm; Weber's length of thorax 1,16 (1,19-1,27) mm. Yellowish-brown; cheeks and occiput rather ferruginous. Integument opaque; head, postpetiole and gaster sharply, rest of body more finely reticulate-punctate. Pubescence scarce and appressed. Erect hairs absent.

Head (fig. 4) longer than broad; sides scarcely convex; occipital corners, not considering the three prominent and subacute teeth, rather broadly rounded. Mandibles striolate, with 6 teeth on chewing border. Anterior margin of clypeus convex, notched in the middle. Frontal area impressed. Frontal carinae convex and covering the antennal socket, prolonged caudad as a pair of prominent ridges, which bifurcate in the rear before reaching occiput; inner branches more approximated to each other, sharp, strongly raised, terminating as a prominent tooth on occiput; outer branches weaker, obliquely running caudad, fading out before reaching the occipital corner. Occiput between mesial teeth excised. Carinule of cheeks distinct, curving mesad posteriorly and fading out at level of eyes.

Thorax (fig. 5) rather slender and elongate; promesonotum in profile convex; impressed at mesoepinotal junction. Pronotum with 3 pairs of spines, one spine anteroventrally at each side, 4 spines dorsally arranged in a transverse row. Mesonotum with 3 pairs of spines, disposed in two longitudinal rows, gradually diminishing in size to the rear. Basal face of epinotum anteriorly with a pair of short, posteriorly with a pair of long, acute, rather elevated spines. Sides of epinotum with a distinct tooth above and somewhat in front of the spiracle.

Petiole (fig. 6) longer than broad, its dorsum posteriorly with a pair of obliquely raised short spines. Postpetiole scarcely longer than broad, subtrapezoidal in dorsal aspect, dorsally strongly flattened with a pair of spinelike tuberosities near the anterior border; posterior border emarginate in the middle; circular pit rather vestigial. Gaster anterolaterally marginate.

The paratypes agree with the holotype in all essential features of structure and livery. Their measurements have already been given in the description of the holotype.

Types - 4 workers. Brazil, Sao Paulo State: Federal highway BR - 2. Sao Paulo - Curitiba, km 40, May 7, 1960 (W. W. Kempf) 2 workers (holotype and paratype); Rio de Janeiro State: Petr6polis, April 21, 1945 (W. W. Kempf) 1 worker (paratype); Santa Catarina State; Chapec6, December 1957 (F. Plaumann) 1 worker (paratype). All specimens in my collection (WWK).

This species differs from parallelus as follows: Clypeus notched in the middle; longitudinal carinae of vertex sharper and more prominent; teeth and spines of occiput better developed, rather acute; occipital corners more rounded; mesonotum with an additional pair of spines; epinotal spines more elevated; petiole longer than broad; postpetiole not longer than broad, having anteriorly on dorsum a pair of prominent tubercles and posteriorly an ill-defined circular pit.

All four specimens were taken as strays from forest floor cover. This may mean another distinctive trait, since parallelus is a denizen of open areas.