Austrogastrura travassosi ( Arlé, 1939 ) sensu Thibaud & Palacios-Vargas (1999)

Fernandes, Liliane Henriques, Bellini, Bruno Cavalcante & Mendonça, Maria Cleide De, 2010, Revision of the genus Austrogastrura Thibaud & Palacios-Vargas, 1999 (Collembola: Poduromorpha: Hypogastruridae), Zootaxa 2542, pp. 61-68 : 62-64

Austrogastrura travassosi ( Arlé, 1939) sensu Thibaud & Palacios-Vargas (1999)

Figs 1–11 , Tab. 1 .

Syn. Choreutinulla travassosi ( Arlé 1970)

Type material. Brazil, Mato Grosso do Sul, Salobra, in the margins of Rio Miranda, 20.x.1938. Arlé coll.; 5 males and 9 females on slides.

Other examined material. Brazil, Paraíba, Cacimba de Dentro, Fazenda Cachoeira da Capivara, 17.vi.2008. Bellini & Zeppelini coll.; 7 males and 6 females on slides Nº1898 CM/ MNRJ.

Redescription. Total body length 1.0 mm. Habitus typical for Hypogastruridae . Body color pale in ethanol; specimens with bright orange color in nature ( Fig. 1 ), eyepatches strongly pigmented. Body elongated, subcylindrical. Cuticular granulation moderate.

Antennae shorter than head diagonal, measuring 150Μm and 170Μm, respectively; antennal segment IV with trilobed apical vesicle, subapical organite, lateral microsensillum and five subcylindrical sensillae; sensory organ of antenna with two globular exposed microsensilla, two guard sensilla and one microsensillum on ventral side; antennal segments I and II bear 7 and 12 setae, respectively ( Figs 2, 3 ).

5+5 eyes measuring 12Μm; postantennal organ with 4 lobes arranged in a circle, measuring 12Μm ( Fig. 4 ). Chewing mouthparts typical for Hypogastruridae ; maxilla with 3 teeth and 6 fringed lamellae; maxillary outer lobe with 2 sublobal hairs; labium with 5 papillae (A–E); labral chaetotaxy: 2/544.

Leg setae from I to III as follow: precoxae 0,3,3; coxae 4,6,6; trochanters 6,6,5; femora 12,11,11; tibiotarsi 18,18,17, three of them are slightly spatulated tenent hairs, M seta present; two pretarsal setae. Ungues (24m) with one tooth on apical third of inner margin; unguiculi absent ( Fig. 5 ). Ventral tube with 4+4 setae ( Fig. 6 ). Tenaculum with 3+3 teeth. Furca complete; dens short, measuring 42Μm, with 6 dorsal setae, one internal longer than others; mucro slender, about 1/2 of dens length, with notch in apical part ( Figs 7, 8 ). Anal valves with 15+15 setae and 3+3 hr setae ( Fig. 9 ). Male plate with about 28 genital smooth setae; female plate with 2 eugenital setae and 6–8 circumgenital setae ( Fig. 10 ). No anal spines.

Dorsal micro- and macrosetae on head and body ciliated; sensory setae smooth; setae on abdominal segments V and VI much longer than others ( Fig. 11 ). Head sd2 seta present; a0 and c1 setae absent; two Oc setae present. Thoracic segment I bears 2+2 dorsal setae; thoracic segments II and III with two sensillae (m6/ 7 and p4); no lateral microsensilla. Abdominal segments I–IV with one pair of sensillae in position p4, on abdominal segment V in position p3. Ventral chaetotaxy of head and body with simple, smooth thin setae.

Remarks. The detailed examination of the type material and other specimens of A. travassosi collected by Roger Arlé made possible the redescription of the species. Furthermore, it testified that the redescription of A. travassosi made by Thibaud & Palacios-Vargas (1999) was incorrect. It was based on specimens from Restinga da Marambaia and Prainha, southeastern Brazil, which is far from the type locality of A. travassosi and the specimens collected by them actually belong to a new species, described below in this paper. For differences between these two species see remarks to A. marambaia sp.nov.

Choreutinulla edaphica Rapoport, 1962 , was pointed out by Arlé (1970) as synonym of A. travassosi . With the redescription of the late species and the comparison with the original description of C. edaphica and a better characterization given in Najt (1969), we conclude C. edaphica is not a synonym of A. travassosi . The first species has smooth setae covering the body, apical vesicle of the fourth antennal organ inside a tegumentary fold, tibiotarsi without tenent hairs and ungues without any internal teeth, contrasting with the redescription of A. travassosi . In fact, the combination of distinct characteristics of C. edaphica plus a higher rate between dens and mucro was not observed in any other species of Austrogastrura (see Table 1 ). In the other hand, C. edaphica is clearly an Austrogastrura species for presenting the following combination of characters: 5+5 eyes, PAO with four lobes, forth antennal segment with five sensilla, six setae on the dorsal dens and absence of anal spines. Even if we could not have access to the type series of C. edaphica , its identity as a valid species is supported by the literature ( Rapoport 1962, Najt 1969). For this reason we revalidate the species as Austrogastrura edaphica ( Rapoport, 1962) comb. nov.

A. travassosi can be easily distinguished from A. lobata and A. edaphica by ciliated dorsal setae, trilobed apical organ of the forth antennal segment, and clear inner tooth on unguis. Other morphological features of the species of the genus are compared in Table 1 .

Distribution. Good’s biogeographic zone 27: South Brazilian ( Good 1974).

Habitat. The type location of A. travassosi is Salobra municipality, Mato Grosso do Sul State, western Brazil. The specimens were collected over wet cow tracks and moist soil at the margins of Rio Miranda. The climate of this region is ‘Aw’ according to Koeppen’s system, which indicates a tropical climate with rainy summers and dry winters ( Kottek et al. 2006). A. travassosi was also found in Cacimba de Dentro municipality, in Paraíba State, northeastern Brazil. The climate of this region is ‘As’ according to Koeppen’s system, which means an equatorial climate with two distinct seasons: a dry summer and rainy winter ( Kottek et al. 2006). The area is located in a semi-arid biome named Caatinga, which flora is xeromorphic, basically composed by small trees, bromeliads and cacti. Specimens of A. travassosi forms aggregations, which are well visible due to theirs bright orange color ( Fig. 1 ). This behavior was observed only during wet season and specimens were found over rocks and above dead foliage. Apart of this period, when specimens formed aggregations, we didn’t see A. travassosi on the environment.

Figures

FIGURE 1. Alive specimens of Austrogastrura travassosi.

FIGURES 2 – 11. Austrogastrura travassosi: 2, antenna; 3, sensory organ of the antennal segment III; 4, right eye patch and postantennal organ; 5, tibiotarsus and pretarsus with unguis of leg III; 6, ventral tube; 7, dens and mucro; 8, mucro (dorsal view); 9, anal valves and male plate; 10, female plate; 11, dorsal chaetotaxy (one ciliated seta on detail).