Mycetarotes parallelus (Emery)

Kempf, W. W., 1960, A review of the ant genus Mycetarotes Emery (Hymenoptera, Formicidae)., Revista Brasileira de Biologia 20, pp. 277-283 : 279-282

Mycetarotes parallelus (Emery)

(Figs. 1-3, 7-13)

Cyphomyrmex parallelus Emery , 1905: 162-163, fig. 23 (Worker, female; Brazil Mato Grosso: Coxipo).

Atta (Mycocepurus) luederwaldti Forel , 1911: 293-294 (Worker, female; Brazil Sao Paulo City: Ipiranga). New Synonymy.

Mycocepurus luederwaldti Luederwaldt , 1918: 68 (Nest).

Types - M. parallelus , workers and female collected by F. Silvestri, in the Emery collection at Genova, Italy; not seen. M. luederwaldti , workers and female collected by H. Luederwaldt, in the Forel collection at Geneva, Switzerland; syntypes in DZSP and CTB examined.

Worker - For a full description see Emery (1905). All specimens examined by myselft differ from the description and figure of the type in having the head slightly less elongate and the more or less vestigial carinule on genae not really prolonged caudad to the lateral occipital tooth, but curving mesad and terminating at the level of the eyes. I believe that Emery slightly exaggerates the head length. As regards the carinule, the base of the lateral occipital tooth is prolonged foreward in the form of a very indistinct and blunt margination which, in full face view, gives the impression of a carinule meeting, and joining up with, the carinule coming from the anterior end of the cheeks.

The distinguishing characters for this caste consist in the entire clypeus border, the rather feeble longitudinal ridges on vertex, the less conspicuous and more obtuse occipital teeth (fig. 1). Thoracic spines rather blunt and low, there being only two pairs of spines on the mesonotum (fig. 2). The petiole is about as broad as long. The postpetiole lacks anteriorly a pair of well-defined tuberosities, is more elongate and has posteriorly on dorsum a pronounced circular impression (fig. 3).

Female - Already described by Emery (1905), who also gives a figure of the head. As regards the genal carinule, there applies the same as stated above for the worker. The wings, hitherto unknown, are identical with those of the male sex (see below and figs. 10, 11).

Male (undescribed) - Total length 3,7 mm; maximum length of head capsule 0,65 mm; maximum width bf head including eyes 0,80 mm; maximum diameter of eyes 0,29 mm; length of scape 0,31 mm; Weber's length of thorax 1,16 mm; length of fore wing 2,86 mm. Fuscous reddish-brown; head more infuscated than rest of body; funiculi and legs more testaceous-brown. Wings smoky brown with dark brown veins. Integument finely but sharply reticulatepunctate and opaque. Erect hairs absent. Appressed hairs generally sparse and inconspicuous; longer, subappressed on clypeus, underside of head, anteromesial face of coxae and tip of gaster.

Head as shown in fig. 9. Chewing border of mandibles vestigially denticulate with a distinct apical and subapical tooth. Palpi 4 (3): 2. Median portion of clypeus strongly vaulted in both directions. Frontal carinae obliquely raised laterad. Scape shorter than funicular segments I-III combined, failing to attain the occipital corner when laid obliquely back over the head. Funicular segment I distinctly shorter than segment II. Ocelli on prominent tubercles. Occipital corners tridentate. Occiput excavate.

Thorax as shown in figs. 7, 8. Pronotum with a strong scapular spine. Mesonotum with fine rugulae, anteriorly and laterally vaulted, with deeply impressed Y-shaped Mayrian furrows or notauli. Prescutum with a shallow median longitudinal impression, laterally marginate above, before dropping down to the furrow of the notauli. Mesoscutal sclerites laterally sharply marginate and projecting, disc longitudinally impressed laterally, with a longitudinal swelling flanking the common stem of the Mayrian furrows. Transcutal furrow broad and deeply impressed, bisected in the middle by a sharp, short, longitudinal carina. Paraptera with a pair of appendages, the anterior lobate, the posterior dentate. Scutellum with a pair of stout, raised, longitudinally carinate tuberosities, terminating posteriorly in a pair of strong spines. Basal face of epinotum with a prominent tubercle at each side and an acute spine at the posterior corner. Wings as shown in figs. 10, 11. Note the clearly defined pterostigma and the venation of the Formica-type in the fore wing.

Pedicelar segments resembling those of worker. Pair of spines on petiole reduced to short, blunt teeth. Postpetiole flattened and depressed, without a circular pit in front of the posterior border. First gastric tergite with a longitudinal median impression. Genitalia as shown in figs. 12, 13. Note the spinelike process dorsally on clasping surface of paramere and the hooklike digitus of the volsellae (fig. 12).

Description based on 12 males from the same colony, which did not offer any noticeable variation as regards measurements and structural characters.

Distribution - From central and southeastern Brazil to northern Argentina.

Specimens examined - Brazil, Goias State: Anapolis (W. W. Kempf) 1 worker (WWK)); Rio de Janeiro State: Escola Nacional de Agronomia, km 47 (C. R. Goncalves) 41 workers, 2 females, 12 males (DDSV, WWK), Tres Pocos(T. Borgmeier) 1 worker (CTB); Sao Paulo State: Agudos (W. W. Kempf, R. Mueller) 4 workers (WWK), Guaratingueta (W. W. Kempf) 1 worker (WWK), Sao Paulo (H. Luederwaldt) 5 workers (nidotypes of M. luederwaldti Forel ) (DZSP, "CTB), Sao Paulo, Institute de Botanica (W. W. Kempf) 4 workers, 1 female (WWK). Argentina: Tucuman (N. Kusnezov) 4 workers (CTB).

Synonymy - As Borgmeier (in litt.) already surmised, M. luederwaldti (Forel) is nothing but a synonym of parallelus (Emery) . The nidotypes of the former fully agree with the description and figures of the latter as given by Emery (1905).

Biology - According to Luederwaldt (1918) this ant lives in the open fields. Nest were found at the same sites where Mycocepturus occurred, but were less common. A nest in good conditions to be more carefully examined, was found in the soil at a depth of approximately 15 cm. The sphaerical cavity measured about 4 cm in diameter. The fungus garden did not consist of separated and suspended lobulate clusters as is the case in Mycocepurus goeldii , but formed a single, solid and homogeneous mass fastened to the bottom and to rootlets traversing the cavity.