Brachystomellidae, Stach, 1949

Janion-Scheepers, Charlene & Deharveng, Louis, 2022, A shocking-red new species of Setanodosa Salmon, 1942 (Collembola: Brachystomellidae) from South Africa, Zootaxa 5154 (4), pp. 483-495 : 492

Brachystomellidae of South Africa

At present, three genera and seven species of Brachystomellidae are known from South Africa including S. jacquesi sp. nov. The map ( Fig. 9 ) indicates the geographical locations of published records ( Janion-Scheepers et al. 2015) and barcoded specimen records of this study. It highlights large geographical gaps, which are not real, as Brachystomella is widespread and common in most regions of South Africa. All species are known from the southern part of the country as most collection efforts have been concentrated in this area ( Janion-Scheepers et al. 2015). Interestingly, a single record of Brachystomellidae has been published for the whole Ethiopian region outside South Africa ( Thibaud 2013), Brachystomella contorta Denis, 1931 from Ivory Coast, a species considered as pantropical ( Zon et al. 2013). This species was not present in the material examined so far from South Africa. Despite the paucity of distributional data, the rarity of the family Brachystomellidae north of southern South Africa may reflect the wellknown global pattern of a southern hemisphere distribution of the family, which is extensively documented in the literature ( Najt & Weiner 1996, Weiner & Najt 2001, Greenslade 2018).

One genus ( Probrachystomellides ) and four species of Brachystomellidae ( P. nicolaii , Brachystomella parvula africana , B. coatesi and B. georgensis ) are endemic to South Africa. One additional species of Brachystomella , B. parvula ( Schäffer, 1896) , has a wider distribution and is possibly introduced. This species, considered cosmopolitan in distribution ( Fjellberg 1998), is the most frequently cited from South Africa, but these ancient records need confirmation, as we have not found it so far in our samples (since 2008). According to Weiner & Najt (1991), Brachystomella platensis Najt & Massoud, 1974 , described from South America ( Najt & Massoud 1974) where it was probably introduced, but mostly present in Australia ( Greenslade & Najt 1987, Najt & Weiner 1996, Greenslade 2018), is closely related to B. georgensis from which it differs by a few characters. We provisionally assigned the specimens of most South African populations that we have barcoded to this species, as cf. platensis ( Table 1 ). A most interesting side-result of our study is that COI sequences of specimens of this species from Australia (Melbourne) are identical to those of specimens from South Africa. Brachystomella cf. platensis is therefore present in both regions. Its identity is however uncertain, given in particular its similarity with B. georgensis . This will be checked in further morphological and molecular studies which are beyond the scope of this paper. The only species of Setanodosa described from South Africa, S. capitata , has also been recorded from Australia by Womersley (1939), a record which seeks confirmation ( Greenslade 1994).

The genus Brachystomella is by far the most common in soils of southern South Africa, with several unpublished records of unidentified species that were not considered in this paper. Ecologically, it is present in soil, less frequently in more xeric habitats. The genus Setanodosa is much less frequently observed. Morphologically, it corresponds to the “hemiedaphon xerophil” biological form of Gisin (1943), with its very developed and strongly clavate tenent hairs. The genus is found on rocks but is also present in litter. However, the number of records, most of unidentified species, is not enough to speculate on the ecology of Setanodosa species. The third genus, Probrachystomellides , is only known so far from the type locality ( Probrachystomellides nicolaii ).

Figures

FIGURE 9. Distribution map of Setanodosa jacquesi sp. nov. and Brachystomellidae recorded to date from South Africa based on the checklist of South African Collembola (Janion-Scheepers et al. 2015) and barcoded material (Table 1).