Mycetophylax

Klingenberg, C. & Brandão, C. R. F., 2009, Revision of the fungus-growing ant genera Mycetophylax Emery and Paramycetophylax Kusnezov rev. stat., and description of Kalathomyrmex n. gen. (Formicidae: Myrmicinae: Attini)., Zootaxa 2052, pp. 1-31 : 5-7

Mycetophylax Emery, 1913

(Figs. 1-3, 6 a-g, 7a)

Cyphomyrmex (in part) Mayr, 1884: 9

Myrmicocrypta (in part) Wheeler, 1907: 728; Forel 1907: 144

Cyphomyrmex (Mycetophylax) Emery 1913: 251; key to species, Santschi, 1922: 357; raised to genus by Santschi 1923: 268

Myrmicocrypta (Mycetophylax) Santschi, 1916: 383, Gallardo, 1916: 320

Sericomyrmex (in part) Santschi, 1916: 383

Type species: Myrmicocrypta brittoni (Mayr, 1884) (original designation) (junior synonym of Mycetophylax conformis )

Worker: Monomorphic ants belonging to the Attini tribe. Integument areolate, smooth and shiny at the metapleural gland. Sculpture of the mandible discs varies between species. Hairs short, appressed.

Head longer than wide, almost triangular, the greatest width of head at posterior third. Compound eyes at the anterior third of head capsule, convex, surpassing the lateral margin in frontal view. Anterior margin of labrum slightly concave in the middle otherwise rounded. Triangular mandibles with seven to ten teeth at masticatory margin, which is smooth, without any trace of sculpture. Apical teeth longer than the others, which are reduced in size basally; the most basal tooth appearing as a denticle. Posterior portion of clypeus extending up to the level of the antennal insertions. Posterior margin of clypeus visible as a distinct suture; frontal area triangular and shallowly impressed. Area between preocular carina and frontal carina free of hairs, distinct (in M. morschi this area is particularly impressed, although the lateral expansion covers only the base base of the scapes, and not as in the true antennal scrobes of Cyphomyrmex , where most if not all of the scape can be lodged inside the scrobe). Frontal lobes laterally produced and covering the antennal insertions; frontal carinae reaching the posterior third of the head. Vertexal margin concave; posterolateral lobes rounded.

Mesosoma without spines, smooth or bearing only rounded protuberances. Pronotal shoulders rounded. Promesonotum moderately convex in profile. Propodeal spiracle clearly visible, as well as the opening of the metapleural gland. Petiole longer than high; in lateral view, peduncle very short, with an undifferentiated node. Subpetiolar process always distinct, blunt, with rounded apex. In dorsal view, postpetiole always wider and longer than the petiole. Posterior margin of postpetiole straight, without an impression or distinct lobes. Gaster without tubercles or protuberances; a little smaller than the head.

Gyne: Color, pilosity and sculpture as in conspecific workers, but with three equally developed ocelli in the middle of the head. Anteriorly rounded scutum, scutum-scutellar sulcus convex in relation to the scutum. Axilla well developed. Parapsides almost indistinct, set between parapsidial lines and latero-posterior margin of the scutum which is limited by a carina. Anepisternum and katepisternum divided by a suture. Katepisternum anterior border sinuous. Petiole, postpetiole and gaster like those of the workers. Gaster with the same width as the head.

Male: Pilosity similar to that of conspecific workers and gynes. Triangular mandibles with five to seven teeth; the apical always longer than the others. Clypeus bulging until the frontal area. Head without antennal scrobes, at most with a depressed area where the antennae articulate; antennal scapes almost twice as long as the funiculus and always surpassing the posterolateral corners of the head. Small, impressed, hairless frontal area. Compound eyes set at the anterior half of head, occupying almost half to one fourth of its lateral margin, in full face view. Three equally developed ocelli. Antennae with 12 to 13 segments. Anterior part of scutum smooth with a median hairless furrow. Parapsidial lines parallel in relation to the main body axis. In dorsal view, prescutellum slender and scutellum narrower posteriorly. Posterior border of scutellum concave, with two protuberances directed backwards. Katepisternum and anepisternum divided by a distinct suture. Petiole and postpetiole like those of conspecific workers. Gaster slender, twice as wide as the postpetiole, with the same width as the head including compound eyes.

Comments: The species of the more narrowly defined Mycetophylax can be easily separated from other Attini by the subtriangular head shape, well developed frontal lobes which completely cover the antennal insertions, absence of deeply impressed antennal scrobes (see comments for M. morschi below), triangular mandibles, median clypeal seta present, mesonotum without spines or protuberances, and the posterior margin of postpetiole straight without any impression; in alate forms the radial cell of forewing is closed (see diagnoses and descriptions). The lack of a well supported phylogeny for the Attini does not afford hypotheses on the evolutionary history of most characters, but these character states in combination are exclusive to Mycetophylax in the revised concept.

Mycetophylax , in this new definition, is a rather compact taxon, including three species that nest only in "restingas" (sandy dunes) along the South Atlantic coast, where they may be locally abundant, and in Venezuela and Puerto Rico, along beaches of the Caribbean Sea. Mycetophylax conformis was found inland only once in French Guiana (U. Mueller, pers. comm.), but also nesting in sandy soil. For geographic distribution see map (Fig. 7 a).

At the Isle of Florianopolis (state of Santa Catarina, Brazil), M. simplex and M. morschi occur at the same beaches, but do not compete for fungus substrate. M. simplex builds nests in the bare sandy area, while M. morschi prefers areas covered with permanent vegetation. Biological data or life history observations are too scant to afford any interpretation. For observations on nest and colony structures of these species see Klingenberg et al. (2007).

Identification key for workers and gynes of Mycetophylax

1. Head as long as wide or a little longer than wide (CI 91-106). Vertexal carina absent. Antennal scapes not attaining the posterolateral corners of the head. Mesosoma smooth without acute spines or protuberances, dorsal profile almost straight in lateral view....................................................................................................................................... 2

- Head longer than wide (CI 82-97). Vertexal carina present. Antennal scapes surpassing the posterolateral corners of the head. Dorsal profile of mesonotum, in lateral view, with an anterior, low, but discernible tumulus. Also in lateral view, scutum of gynes lower in relation to the other Mycetophylax gynes (Fig. 2 c, d, h, 6 c)... Mycetophylax morschi

2. Color brownish to yellow. Mandibles with eight to nine teeth. Integument of the frontal lobes semitransparent, resulting in a pair of round transparent structures above the antennal insertions. Juncture of posterior and dorsal margins of propodeum angulate in side view, not spinose. Gaster without ventral keel (Fig. 3 c, d, h, 6 e)........................

................................................................................................................................................... Mycetophylax simplex

- Color dark brown to black. Mandibles with eight to ten teeth. No transparent integument patch on frontal lobes. Propodeum armed with a pair of spines. Gaster with a faint ventral keel (Fig. 1 c, d, h, 6 a)........................................ ................................................................................................................................................ Mycetophylax conformis

Identification key to Mycetophylax males

1. Head wider than long, vertexal margin convex or straight. Antennal insertions not fully covered by frontal lobes. Pronotum mostly concealed by the scutum, barely visible with the mesosoma in dorsal view (Figs 1 e, f, 3, e, f, 6 a, b, e, f 7). Propodeum unarmed......................................................................................................................................2

- Head longer than wide, vertexal margin concave to straight. In larger specimens, posterolateral corners of the head with protuberances. Frontal lobes covering antennal insertions. In dorsal view scutum covering pronotum only at posterior two thirds (Figs. 2 e, f, 6 c, d). Posterior margin of scutellum convex, with distinct short projections. Propodeum armed with a pair of spines.............................................................................................. Mycetophylax morschi

2. Antennae with 13 segments. Clypeus not separated from the frontal area by a distinct suture. In lateral view, scutum higher than pronotum at the level of the pronotal posterior margin. Posterior margin of scutum slightly convex........ ................................................................................................................................................... Mycetophylax simplex

- Antennae with 12 segments. Posterior border of clypeus distinct from the frontal area by a rounded suture. At the level of the posterior margin of the pronotum, in lateral view, the pronotum and scutum have the same height. Posterior margin of scutum straight................................................................................................. Mycetophylax conformis