Stenognathriopes (Tenentiella) janssensi, Zeppelini & Silva, 2012

Zeppelini, Douglas & Silva, Diego Dias Da, 2012, A new Stenognathriopes (Collembola, Symphypleona, Bourletiellidae) from Brazilian coast, Zootaxa 3540, pp. 51-58 : 52-57

Stenognathriopes (Tenentiella) janssensi sp. nov.

Figs 1–30, Tab. 1

Type material. Holotype: female Brazil: Paraíba, João Pessoa , 3.iii.2009, D. D. Silva coll., on slide Deposited at Museu Nacional — Universidade Federal do Rio de Janeiro (MNRJ-UFRJ) number 2296 . Paratypes, 1 male same slide with holotype. 1 male and 5 juveniles, same data as holotype .

Other material. Female , Brasil: Paraíba, João Pessoa, 14.viii.2010, D. D. Silva coll., on slide, MNRJ-UFRJ number 2297. Male, Brasil: Paraíba, Conde, 21.ii.2010, D. D. Silva coll., on slide, MNRJ-UFRJ number 2298. 2 females and 2 males, Brazil: Paraíba, Pitimbú, 07.ix.2010, D. D. Silva coll., on slide MNRJ-UFRJ number 2299 .

Etymology: The species was named after Frans Janssens (University of Antwerp) as recognition to his remarkable contributions to the study of Collembola.

Description. Body and head purple with yellow spots all over ( Fig. 1B), some specimens with a white yellowish stripe covering most of dorsal great abdomen ( Fig. 1A); antennae and legs white yellowish. Head shape subtriangular due to elongated mouth parts.

Length. Total length 2.2 mm, body 1.3 mm, head 0.8 mm, antennae 0.9 mm, furcula 0.9 mm, habitus sminthuroid ( Fig. 2).

Head. Eyes 8+8 with one microseta between lenses A and C; labral chaetotaxy: a: 4, m: 3, p: 5 ( Fig. 3); clypeus with acuminate setae; posterior cephalic chaetotaxy as in figure 4, macrochaeta M4, ML5–6, IL2–3 and L1 spinelike. In latero-ventral position there is a seta between a pair of oval organs in each side of the head. Mandibles elongate, maxillae slender with narrow maxillary head ( Fig. 29) with narrow head as typical for the genus.

Antennae. Antennal segmentation ratio: 1: 2.4; 2.14; 5.35. Ant I with 7 setae varying in size, two of these are microsetae in proximal position ( Fig. 5); Ant II with 9 setae and 4 microsetae disposed in a latero-ventral position ( Fig. 6); Ant III with 4 spinelike dented setae inserted at the clear basal swelling ( Fig. 7). Apical organ of Ant III with 2 sense rods, Aai microsensillum acuminate ( Fig. 8). Ant IV with 9/10 subsegment ( Fig. 9), apical sensillum present ( Fig. 10). Antennae ~1.12 as long as cephalic length.

Leg I. Coxa with 1 seta; trochanter 4 setae ( Fig. 11); femur 12 setae, the external 3 with one or more rough dentations, 1 curved spine on medial surface, 1 oval organ laterally ( Fig. 12); tibiotarsus with 47 setae, 4 oval organs dorsally, tibiotarsal setae thick and coarsely serrated ( Fig. 13). 3 tenent hairs, one very big conical and lamellar, and two thick and capitated. Pretarsal setae absent. Unguis I with one tooth on external lamella, tunica absent; unguiculus acuminated, apical filament longer than unguis ( Fig. 14).

Leg II. Coxa with 3 setae; trochanter 6 setae ( Fig. 15); femur 16 setae and one oval organ ( Fig. 16); tibiotarsus with 44 setae and 4 oval organs, tibiotarsal setae thick and coarsely serrate; 3 tenent hairs, one very big conical and lamellar, and two thick and capitated ( Fig. 17). Pretarsal seta absent. Unguis II with one tooth on external lamella, without tunica; unguiculus acuminated, apical filament longer than unguis ( Fig. 18).

Leg III. Coxa with 4 setae; trochanter 6 setae ( Fig.19); femur 14 setae, one microseta medially, 2 oval organs, one medial one lateral ( Fig. 20); tibiotarsus with 46 setae, 4 oval organs, tibiotarsal setae thick with some strong dentations; 2 tenent hairs, one very big conical and lamellar, and one thick and capitated ( Fig. 21). Pretarsal seta absent. Unguis III with one tooth on external lamella without tunica; unguiculus acuminated, apical filament longer than unguis ( Fig. 22).

Abdominal appendages. Furca, manubrium 7+7 posterior setea; dens chaetotaxy as shown in figure 23, ventral dental setae 3:3:1:1:1, one seta of the second row small and displaced laterally. Mucro with edges smooth, ratio mucro, dens, manubrium 1: 3: 4.5 ( Fig. 23). Tenaculum tridentate with 3 apical setae on corpus ( Fig. 24). Ventral tube with 1+1 setae at distal part.

Thoracic segmentation not visible, at least one seta per segment.

Great abdomen. Macrosetae thick, blunt and finely dented, acuminate mesosetae present, tricobothria in linear pattern ( Fig. 25).

Small abdomen. Female anal valve chaetotaxy shown in Fig. 26, macrosetae E and F on upper valve thick and blunt, E2 and F2–3 roughly shaped, setae of series C and D slightly serrated, subanal appendage palmated and deeply branched, oval organs present on upper and lower valves ( Fig. 27), male anal valve in Fig. 28.

Biotope. Type locality is an urbanized beach in a residential neighborhood, along the coastal line of Joao Pessoa, capital of Paraiba, Northeastern Brazil ( Fig. 30). This area hosts about 7 km of nesting beaches for sea turtles and presents a narrow belt of vegetation about 30m wide in average. The vegetation is composed of more than 47 species of vegetation psamophyta heliophile ( Almeida et al. 2009), with predominance of crawling vegetation and shrubs. The sand dune is sparsely covered by leaf litter which is the habitat of the new species. The litter dries up completely from mid summer to the beginning autumn. Climate according to Köppen’s system is Am ( Koppen 1936; Shear 1966).

Distribution. Northeastern and Central Brazil (Good’s biogeographic zone 27) ( Good 1974, Christiansen & Bellinger 1995, Culik & Zeppelini 2003). All specimens were found in similar habitats on four localities, municipalities of Mataraca, Conde, Pitimbú and type locality João Pessoa. The distribution covers the whole coast of Paraíba State ( Fig. 30), meaning that the new species is likely to be found over the coast of northeastern Brazilian region, considering the similarity of available habitats.

Remarks. Some specimens present 10 inconspicuous subsegments on Ant IV. There may be some differences in the number of setae on femora depending mainly on the developmental stage of the specimen. This species shares the presence of 2+2 oval organs on head and one tooth on the external lamella of all ungues, with S. (Tenentiella) siankaana , and can be differentiated from it by the number of subsegments on Ant IV (14 in the Mexican species), the shape of tenent hair and tibiotarsal setae coarsely dented. It can be differentiated from other Stenognathriopes by the presence of oval organs on head and anal valve, shape of tenent hairs, number of Ant IV subsegments and a clear tooth on the external lamella of ungues.

The genus Stenognathriopes is composed of seven species, divided in two subgenera, Stenognathriopes and Tenentiella . The condition found in S. (Tenentiella) janssensi , sp. nov., in some characters which are diagnostic for both subgenera (e.g. coarsely serrated spines on tibiotarsus, not seen in the Mexican species, and the external tooth on all ungues, absent in all species of the subgenus Tenentiella ) makes difficult to determine which subgenera the species belongs to, it can be an indication that differences among the subgenera maybe a morphological continuous.

The description of the species S. yemenensis ( Bretfeld 2005) lacks some very important information about diagnostic features used by Betsch and Lasebikan (1979) to differentiate the genus Stenognathriopes from Rastriopes . The elongated shape of mandible and maxillae, shape of the head, tibiotarsal setae, oval organs on tibiotarsus and basal swelling on third antennal segment bearing dented spines. These features are constant in all species of the genus and it is likely that the information was simply omitted in the description instead of lacking in the species. The author mentioned that the chaetotaxy of head and tibiotarsus was not studied in S. yemenensis . Finally Bretfeld (2005) include an unpublished species from Brazil in the identification key that matches with the new species described here.

The new species resembles the Mexican S. (T.) siankaana , presenting modified condition of the tenent hair, the presence of cephalic oval organs and a tooth on the external lamella of ungues I–III. A detailed revision of specimens of all described species of the subgenus Stenognathriopes is needed, because some details of chaetotaxy and the presence of oval organs were not described clear enough, at least in the older ones, to allow further advances in the phylogenetic interpretations. The shape of the tenent hairs is also a matter of concern due to different standards of detail in the descriptions made for the structure, also the definitions for capitate, cylindrical, lamellar, are hard to differentiate with optic microscopy and can give room to some imprecision in the subgenera diagnostic. This deficiency can be solved with scanning microscopy.