Folsomiella albida ( Arlé, 1959 )

Mendonça, Maria Cleide De, Fernandes, Liliane Henriques & Abrantes, Edu- Ardo Assis, 2005, Two new species of Folsomiella Bonet and redescription of F. albida (Arlé, 1959) (Collembola, Brachystomellidae), Zootaxa 1006 (1006), pp. 11-21 : 11-21

Folsomiella albida ( Arlé, 1959)

( Figs. 24–30)

Organella albida Arlé, 1959

Folsomiella albida Salmon, 1964

Length: 0.68–1.55 mm. Entirely white. Body with middle­sized granulation. Chaetotaxy of smooth, thin setae sparsely distributed from thorax to abdominal tergite III; setae of abdominal tergite IV­VI longer, slightly serrated, with their apexes thickened; sensorial setae smooth and acuminate, arranged at each half­tergite following the formula: 022/ 21111. Dorsal chaetotaxy as in Figure 24.

Antennae shorter than the head diagonal, measuring 135 ìm and 165 ìm, respectively; antennal segment IV with apical vesicle bearing one lobe, subapical organite present, one lateral microsensillum, six subcylindrical sensilla; sensory organ of antennal segment III with two rounded microsensilla in a thin integument fold, two subcylindrical guard sensilla, one microsensillum at ventral side; antennal segments I and II with seven and twelve setae, respectively ( Fig. 25). Without eyes; postantennal organ formed by eleven or twelve vesicles arranged in ellipse measuring 20 µm ( Fig. 26). Maxilla globular, with eight teeth, maxillar head of 25 µm ( Fig. 27). Labral quetotaxy: 2/2334.

Tibiotarsi I, II and III with 19, 19 and 18 setae, respectively, with one thin tenent hair, seta M present. Unguis measuring 30 µm, one tooth at the inner lamellae and one pair of teeth at the lateral lamellae ( Fig. 28).

Ventral tube with 3+3 setae; tenaculum with 3+3 teeth. Manubrium with 14 setae; dens measuring circa 20 ìm, with 5+5 setae at dorsal side and a straight mucro, measuring 12 ìm, with its apex slightly curved ( Fig. 29). Female genital plate with ten setae, including two smaller setae placed near the genital furrow and five distal ones arranged in a semicircle. Each even anal valve with 2 setae hr ( Fig. 30).

Examined Material: Brazil: Rio de Janeiro state: Rio de Janeiro city, National Park of Tijuca : one specimen in slide Nº 874 CM / MNRJ ; three specimens in slide Nº 875 CM / MNRJ, 23­IX­1999, M. C. de Mendonça col. ; three specimens in slide Nº 1386 CM / MNRJ, 28­VIII­2003, E. A. Abrantes col. ; two specimens in slide Nº 1460 CM / MNRJ, 25. III.2004, M. C. de Mendonça col. Teresópolis, Granja Comary : 10 specimens in slide Nº 1150 CM / MNRJ, 29­XI­2001, R. Eizemberg col.

Discussion: F. albida was briefly described by Arlé (1959), based on specimens from Teresópolis and from Tijuca Forest, both localities in Rio de Janeiro state, Brazil. Additional specimens collected in both above cited localities were carefully compared with the original description of F. albida and only differed slightly. In the chaetotaxy, Arlé cited the presence of thin and smooth setae at the last abdominal segments and acuminate out that some of those setae were longer than the dens: mucro. Our specimens have the last tergites (IV­VI) covered by serrated setae, with their apex slightly thickened. The maxilla of our specimens bear eight teeth at its apexes, as shown in Figure 27. Although the maxilla in Folsomiella and in the other genera of Brachystomellidae has a very peculiar shape, it was not possible to compare the maxilla of F. albida with that from the other species of the genus, as the shape of the maxilla was omitted in the descriptions of those species.