Micronella itacaman, Queiroz, Gabriel C. & Mendonca, Maria Cleide de, 2013

Queiroz, Gabriel C. & Mendonca, Maria Cleide de, 2013, New species of Brachystomellidae and characterization of Micronella porcus (Denis, 1933) from Brazil, ZooKeys 316, pp. 81-98 : 84-86

Micronella itacaman sp. n. Figs 1-14

Type material.

Holotype: female, on slide. Label: Nº 2332 CM/MNRJ, Itatiaia, RJ, Brasil, Queiroz, G.C. leg, 27.iii.2012, 22°22'59"S, 44°40'1"W. Paratype: 1 female on slide, Label: Nº 2138 CM/MNRJ (D), Itatiaia, RJ, Brasil; Queiroz, G.C. leg, 14.vii.2011, 22°22'59"S, 44°40'1"W. Deposited at MNRJ, Rio de Janeiro, Brazil.

Type locality.

Brasil, Rio de Janeiro: Itatiaia municipality, Parque Nacional de Itatiaia (ICMBio), 22°22'59"S, 44°40'1"W, leaf litter and soil of "campos de altitude", 2,400 m a.s.l.

Other material. One female on slide, Label: Nº 2153 CM/MNRJ (A), Alto Caparaó, MG, Brasil, Queiroz, G.C. leg, 27.vii.2011, 20°26'7"S, 41°47'54"W. Deposited at MNRJ, Rio de Janeiro, Brazil. One specimen deposited at MNHN, Paris, Fran ce: female, on slide, MNHN-EA011504, Teresópolis, RJ. Brasil, Queiroz, G.C. leg; 30.iii.2011, 22°27'38"S, 43°1'45"W.

Description.

Habitus typical of the genus. Body length of holotype: 0.88 mm; body length range of paratypes: 0.63-0.90 mm. Color in ethanol: white, no pigmentation.

Ratio head diagonal: antenna = 1:0.63. Ant I with 7 chaetae. Ant II with 12 chaetae. Ant III and IV fused dorsally, ventral separation marked. Sensory organ of Ant III with two small club shaped sensilla, the mid-ventral one with a bilobed apex; two longer and subcylindrical guard sensilla; ventral microsensillum present (Figs 1-2). All dorsal chaetae of Ant I–III are serrated, ventral chaetae smooth and longer than those from dorsal side (10-13 μm dorsal; 13-15 μm ventral). Ant IV with simple apical bulb and five sensilla, three weakly differentiated from ordinary chaetae; dorsolateral microsensillum present; subapical organite round; with about 30 ventral chaetae (Fig. 2).

Without eyes. PAO bearing 7-8 vesicles disposed as a rosette (Fig. 3). Maxilla quadrangular with 6-7 teeth (Fig. 4). Labral formula: 2/2334. Labium typical of Brachystomella , with one papillated chaeta (L) and four proximal chaetae (Fig. 5).

Head chaetotaxy as in Figs 6-8; asymmetries in the number of axial chaetae. Chaetae a0 present; Oc chaetae 3+3. Dorsal chaetotaxy composed of ordinary serrated chaetae and sensilla subequal in size, becoming longer towards the distal segments of the body (15 µm in Th I and 25 µm in Abd VI) (Fig. 9). Ratio of body ordinary chaetae: sensilla = 1:1. Th I with 2+2 chaetae; sensillar formula by half tergum: 022/211110.

Chaetotaxy of legs I–III as follows: Scx I– 1, 2, 2; Scx II– 0, 2, 2; Cx– 3, 6, 7; Tr– 5, 5, 5; Fe– 12, 10, 10; Tita– 19, 19, 18. All chaetae of Scx I of legs I–III are serrated. Tenent hair on tibiotarsi acuminate; unguis of legs I and II with one extremely minute median inner tooth; tooth not seen on unguis of leg III (Fig. 10). Ventral tube with 3+3 chaetae. Without tenaculum. Furca completely absent, but with a well-defined furcal area with six chaetae arranged in two rows: anterior row with four chaetae and posterior row with two chaetae (Fig. 11). Abd VI with 4+4 serrated chaetae and one unpaired smooth chaetae on dorsal side (Fig. 12). Each anal valve with 12-13 chaetae and 2 hr chaetae; Abd VI with 3+3 smooth chaetae on ventral side (Fig. 13). Female genital plate as in Fig. 14.

Etymology.

“Itakamã” (pronounced itakaman) means "high stone" or "rocky mountain" in the indigenous language Tupi, spoken by the Brazilian natives, reference to the three highest mountain plateaus of southeast Brazil, where the species was found.

Discussion.

The new species, Micronella itacaman sp. n., is well characterized in the genus, as all the species share euedaphic characters such as absence of eyes and furca, but with PAO. It can be distinguished from its congeners by characters such as serrated chaetae on body and five sensilla on Ant IV. In relation to number of vesicles on PAO and ratio of ordinary chaetae: sensilla, the new species is most similar to Micronella porcus , as they have 6-8 vesicles and a ratio of ordinary chaetae: sensilla of approximately 1:1.