Taxonomy of the Proisotoma complex. VI. Rediscovery of the genus Bagnallella Salmon, 1951 and epitoky in Bagnallella davidi (Barra, 2001), comb. nov. from South Africa Potapov, Mikhail Deharveng, Louis Janion-Scheepers, Charlene ZooKeys 2021 2021-11-23 1072 185 204 FA6E65F7-465E-5545-A23A-15E1F95B8A1A Salmon, 1951 Salmon 1951 Collembola Bagnallella GBIF Animalia Bagnallella Collembola 0 185 Arthropoda genus  Type species.   Folsomia sedecemoculataSalmon, 1943  Diagnosis.  Anurophorinaewith all abdominal segments clearly separated and a  Proisotoma-like furca: manubrium with few anterior chaetae (1+1-3+3), dens slender, crenulated, with rather numerous anterior and posterior chaetae, mucro clearly set off from dens, with two or three teeth. 7+7-8+8 ocelli in known species. With simple or bifurcate maxillary palp and four sublobal hairs, two or four prelabral chaetae. Macro s-chaetae 22235 on Abd.I-V. Tergal macro s-chaetae on abdomen situated in front of p-row of chaetae. B-row of chaetae on Ti.1-2 complete (both B4 and B5 present). Ventral chaetae on Th.III present or absent. Sexual dimorphism present or absent.  Position of the genus in the subfamily Anurophorinae. To date an appropriate generic name did not exist for the small group species related to  Proisotoma Boerner, 1901 sensu lato which were discussed in the monograph of Potapov et al. (2006). This group, so-called "  Proisotoma tenella,  Proisotoma ripicola,  Proisotoma biseta", consists of forms sharing characters such as: the three last abdominal segments separated, manubrium with anterior chaetae, four prelabral chaetae, and presence of three and five s-chaetae on Abd.IV and V, respectively. Recently, one more species,  Proisotoma sedecimoculata(Salmon, 1943), became a probable candidate to belong to this group ( Potapov and Janion-Scheepers 2017). This species was described by Salmon (1943)as  Folsomia sedecimoculataand was afterwards proposed as a generotype for the new genus  BagnallellaSalmon, 1951.  Bagnallellawas erected based on three last abdominal segments fused, bidentate mucro and eight ocelli. Later,  Bagnallellawas lost in the taxonomy of the subfamily and was mostly treated as a junior synonym of either  Folsomiaor  Proisotoma. After the examination of the type specimen, it was discovered that the three last abdominal segments were actually separated ( Potapov and Janion-Scheepers 2017). Here, we suggest restoring  Bagnallellafor the group of species mentioned above, rather than erecting a new generic name. Several other forms described under different generic names also fit to  Bagnallellaat lesser or larger degree of accuracy. For these species, the two  Bagnallellakey characters were mentioned in the associated descriptions or were seen by us, apart from three forms with unknown sensillar chaetotaxy. Nevertheless, we suppose the last ones (notated with question marks in the list of species of  Bagnallellabelow) belong to the genus. Among these species,  Bagnallella sedecimoculatais poorly described and so is not the best to be a generotype, but we prefer to keep a generic name already created by John Salmon. The incertae sedis genus  Bagnallellacombines the characters of two large generic groups by the separation of its two last abdominal segments and the presence of three and five s-chaetae on Abd.IV and V respectively in characteristic position. The former character is a diagnostic feature of the  Proisotoma Boerner, 1901 complex, the latter indicates basic set of s-chaetae in  CryptopygusWillem, 1902 and related genera belonging to  Cryptopyguscomplex ( Potapov et al. 2006, 2013, 2020). The latter complex is characterized by the fusion of the two last abdominal segments. The genus  Bagnallellatakes a neatly intermediate position between  Cryptopygus(  Cryptopyguscomplex, Southern Hemisphere) and  Scutisotoma(  Proisotomacomplex, Northern Hemisphere). The three genera share, apart from the characters of the subfamily, the presence of a furca, a mid-tergal position of macro s-chaetae on body tergites, and the absence of any specific apomorphy. The combinations of the two key characters mentioned above are shown in Figure 1. After the separation of the two last abdominal segments, we suggest treating  Bagnallellain the  Proisotomacomplex.   Figures 1-4.S-patterns of Abd. IV-VI in the genera  Cryptopygus Bagnallellaand  Scutisotoma( 1)  B. sedecimoculata( 2) and  B. dubia( 3, 4) 2, 3furca, anterior view 4macrochaetae and s and ms-chaetae on body. s = s-chaetae, ms = ms-chaetae.  Distribution and ecology of    Bagnallella.The genus is distributed worldwide. More local species (  B. davidi,  B. douglasi,  B. mishai,  B. biseta,  B. koepckei) are distributed in the Southern Hemisphere that indicates further relation to the "austral"genus  Cryptopygus. Due to apparent ruderal  B. tenellaand pioneer  B. ripicola, the genus also occurs in the Northern Hemisphere. The ecology of the former species is especially remarkable, as  B. tenellais often recorded in mass abundances ( Agrell 1939; Arle 1970; Neves and Mendonca2016). We speculate that  B. davidihas an unusual biology and ecology due to its morphological modifications (described below).  World list of the genus    Bagnallella   Bagnallella biseta(Rapoport, 1963), comb. nov.   Bagnallella davidi(Barra, 2001), comb. nov.   Bagnallella dubia(Deharveng, 1981), comb. nov.   Bagnallella douglasi( Mendonca, Queiroz & Silveira, 2015), comb. nov. ?  Bagnallella koepckei(Winter, 1967), comb. nov.   Bagnallella mishai( Mendoncaet Silveira, 2019), comb. nov. ?  Bagnallella nigromaculosa(Folsom, 1932), comb. nov. ?  Bagnallella paronai( Boerner, 1907), comb. nov.   Bagnallella ripicola(Linnaniemi, 1912), comb. nov.   Bagnallella sedecimoculata(Salmon, 1943), comb. nov.   Bagnallella tenella(Reuter, 1895), comb. nov.  Descriptions and remarks to species of the genus. Below we give the diagnosis, description, remarks, and distribution, with, if possible, ecological remarks of all species of  Bagnallella. Some sections may be omitted if the associated species have good morphological descriptions in the literature.