Schaefferia cf. quinqueoculata ( Yosii, 1956 )

Babenko, Anatoly, 2019, A new species of Schaefferia Absolon (Collembola: Hypogastruridae) from Chukotka, Russia, with remarks on the related forms, Zootaxa 4571 (2), pp. 247-254 : 252

Schaefferia cf. quinqueoculata ( Yosii, 1956)

Figs 4 , 10

Hypogastrura (Denigastrura) quinqueoculata Yosii, 1956: 12

Type-locality: Atago Iwaya cave, Gifu Prefecture, Japan

Material studied. 4 females and one male (slides) and 4 specimens (alcohol), Minamisaku , Nagano Prefecture, Japan [35.923° N 138.4934° E], forest soil and stripe of mushrooms, 0 5 Nov. 2002, T. Nakamori leg. Deposited in the author’s collection .

Remarks. Yosii (1956) described this species on material from central Japan. Later he ( Yoshii 1991) added further details based on specimens from several caves located in Iwate Prefecture, in the more northern part of Honshu Island. Both descriptions are not complete and partly contradict each other. More detailed description of chaetotaxy is given in his 1991 paper as follows: chaetal pattern is strongly variable, namely, on abd. I–III, s.s. is p-5, the setae m-1, m-3 and m- 4 may be present or absent, on abd. IV s.s. is p-4 and m-1 is often on one side and m- 3, m-4 are usually present. Such a description indicates a high level of variability but does not allow an exact interpretation of the pattern of chaetotaxy. Description of S. quinqueoculata chaetom by Jordana et al. (2012) is simply based on that of Thibaud et al. (2004) who used a broad conception for this species. Yosii’s types of S. quinqueoculata could not be found. There is no such material in Museum of Natural History of Geneva where the main part of the Yosii’s collection is kept (Peter J. Schwendinger, pers. comm.), nor in the sorted collection of Kyoto University Museum (M. Hasegawa, pers. comm.).

Taizo Nakamori (Yokohama National University) collected fresh material of a similar non-cave form from central Japan. As true S. quinqueoculata , it is characterised by the presence of only traces of dark pigment (only eye field clearly darker), usual 7 blunt sensilla on Ant.4, 5+5 ocelli (one specimen with 5+6), typical PAO , 4+4 chaetae on VT, unguis with inner and a pair of lateral teeth, retinaculum with 4+4 teeth, short furca with 5(6) dental chaetae and clearly separate mucro. Its labium is complete with all usual papilla ( Fig. 4 ) which distinguishes this form from S. czernovi . The dorsal chaetae are long, thin and usually smooth ( Fig. 10 ), their distribution is almost stable and only few asymmetries were observed in the material examined. General chaetotaxic pattern is of the typical A - type; that is the head and thorax with all usual chaetae present and abdomen as in Fig. 10 . Using the key in Jordana et al. (2004) the specimens are identified as S. czernovi , but not as S. quinqueoculata . The only sound difference in chaetotaxy of this form is the presence of a 2’ chaetae on Abd.5, i.e. 4+4 a -chaetae situated between macrochaetae p 5 ( Fig. 10 ). The only other described congener with such trait is S. scossiroli Dallai et Sabatini, 1981 from Italy but it has only 3+3 ocelli. It is not possible to definitively decide if the form described above is conspecific with true cave S. quinqueoculata although it is plausible. If so, a higher variability of the species in caves can be explained by long period of isolation. A new collection of this species from the type-locality is needed.

Distribution. Japan

Conclusion. Christiansen & Wang (2006, p. 82) noted that Typhlogastrura Bonet, 1930 is “ an artificial genus consisting of all members of the denticulata branch of Ceratophysella, which have successfully invaded caves and become troglomorphic ”. The same seems to be true for the genus Schaefferia . The species of the latter genus dwell in both edaphic and cave habitats and include Ceratophysella species of the same branch with reduced number of eyes and shortened furca, which may not be closely related to each other. The genus is not especially diverse on the global scale and includes according to Bellinger et al. (2018) only 34 species. Nevertheless, two general revisions have been devoted to it during the last fifteen years, i.e. Thibaud et al. (2004) and Jordana et al. (2012). Neither of these revisions is able to separate S. bermani sp. nov., S. czernovi and S. quinqueoculata . For instance, following Thibaud et al. (2004), would result in the three species being identified as synonyms of S. quinqueoculata . Alternatively, using the key in Jordana et al. (2012), S. bermani sp. nov. would be identified as the European S. maxima , while both S. czernovi (partly) and S. cf. quinqueoculat a as S. czernovi , despite their morphological and distributional differences. The main reason of these anomalies, is a reliance on insufficiently detailed descriptions. Resolution of this confused situation probably requires a revision of most species in the genus based on types and fresh material from the type-localities.

Figures

FIGURES 1–8. Schaefferia bermani sp. nov. (1–2, 5–8), S. czernovi (3) and S. cf. quinqueoculata (4): 1, dorsal chaetotaxy; 2, labial palp; 2a, labial papilla E, lateral view; 3, labial palp; 4, ibid; 5, maxillary head; 6–7, dens and mucro, different views; 8, unguis. Scales: Figs 1—0.1 mm, 2–8—0.01 mm.

FIGURES 9–10. Abdominal chaetotaxy: 9, Schaefferia czernovi; 10, quinqueoculata. Scale: 0.1 mm.