Folsomiella pseudocaeca, Mendonça & Fernandes & Abrantes, 2005

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 pseudocaeca sp. nov.

( Figs. 14–23)

Length: 0.80–0.88 mm. Entirely white. Body with strong granulation. Chaetotaxy of smooth, thin and sparse setae; sensorial setae smooth and acuminate, with three times the length of common setae, and arranged at each half­tergite following the formula: 022/ 21111. Dorsal chaetotaxy as in Figures 14 and 15.

Antennae shorter than the head diagonal, measuring 140 ìm and 160 ìm, respectively; antennal segment IV with trilobed apical vesicle, subapical organite present, one lateral microsensillum, six subcylindrical sensilla; sensory organ of antennal segment III formed by two rounded microsensilla in a integument fold, two guard sensilla with different shape and size: a ventral one, subcylindrical, and a dorsal one, smaller and leaf­shaped, one microsensillum at ventral side ( Fig. 16); antennal segments I and II with seven and twelve setae, respectively ( Fig. 17). Without eyes; postantennal organ formed by seven vesicles arranged in circle, measuring 16 µm ( Fig. 18). Maxilla globular, with eight teeth, maxillar head of 20 µm ( Fig. 19). Labial chaetotaxy as in Figure 20, seta F with approximately twice the length of seta E. Labral chaetotaxy: 2/2334.

Tibiotarsi I, II and III with 19, 19 and 18 setae, respectively, without clavate tenent hair, seta M present. Unguis measuring 23 µm, with one small tooth at the inner lamellae and one pair of teeth at the lateral lamellae ( Fig. 21).

Ventral tube with 3+3 setae; tenaculum with 3+3 teeth. Manubrium with 16 setae; dens measuring 40 µm, with 5+5 setae at dorsal side and a straight mucro, measuring 18 µm, with its apex slightly curved ( Fig. 22). Female genital plate with six setae, including two smaller setae placed near the genital furrow and four distal ones arranged in a semicircle. Each even anal valve with 2 setae hr ( Fig. 23).

Type Locality: State Park of Serra da Tiririca , Niterói, Rio de Janeiro state, Brazil. Found on soil at 1200 m alt., at 18­XI­2002, by J. D. C. Souza .

Type material: Brazil: Rio de Janeiro state: Niterói: State Park of Serra da Tiririca: Female Holotype on slide Nº 1238 CM / MNRJ, 18­XI­2002, J. D. C. Souza col.; one female paratype on slide Nº 1175 CM / MNRJ, 01­III­2002, J. D. C. Souza col.

Discussion: Folsomiella pseudocaeca sp. nov. is very similar to F. caeca (Folsom) , described from Panama, in habitus, structure of antennal segments III and IV, postantennal organ, unguis, furca and the number of dental setae. Although it was not possible to compare the maxilla of F. pseudocaeca with that from F. caeca (as there were no available specimen of this species for comparison and its maxilla has not been illustrated), the different chaetotaxy of F. pseudocaeca allow its easy separation from F.caeca . The new species has only thin and smooth setae, whereas F. caeca has serrated setae distributed over the dorsal side of the head and body, as clearly visible in the illustrations of Najt & Thibaud (1987), based on specimens from Ecuador.

Derivatio nominis: The species is named upon its marked morphological resemblance to F.caeca .