Parabelbella Bulanova-Zachvatkina, 1972

Miko, Ladislav, Ermilov, Sergey G. & Smelyansky, Ilya E., 2011, Taxonomy of European Damaeidae (Acari: Oribatida) VI. The oribatid mite genus Parabelbella: Redescription of P. elisabhetae and synonymy of Akrodamaeus, Zootaxa 3140, pp. 38-48 : 45-46

Parabelbella Bulanova-Zachvatkina, 1972

Type species. Parabelbella crenatosetosa Bulanova-Zachvatkina, 1967 . Synonyms. Epidamaeus (Akrodamaeus) Norton 1987 .

Diagnosis. With general characters of Damaeidae and unnamed subgroup of Damaeus and Epidamaeus sensu lato: i.e., all tibial solenidia free, tibial seta d lost, genua I – III with seta d and solenidion coupled, and with typical damaeid leg setation (usually trochanters 1 – 1 – 2 – 1, femora 7 – 6 – 4 – 4, genua 4 – 4 – 3 – 3, tibia 4 – 4 – 3 – 3 and tarsi 20 – 17 – 17 – 14). Spinae adnatae absent, propodolateral apophysis present or absent. One pair of distinct prodorsal tubercles present (Ba). Sensillus flagellate, usually long, smooth or with fine very short barbs. Parabothridial apophyses unequally developed, Sa longer and sharp, Sp smaller and usually triangular. Ventral tubercle Va well developed, triangular or tooth-like; other tubercles (Vp, E2a, E2p) usually developed as distinct tubercles or ridges, rarely with some absent.

Known species. Altogether seven North and South American, and European species belong to this genus with some certainty. A list of the seven species follows:

P. crenatosetosa Bulanova-Zachvatkina, 1967 (type-species)

P. elisabhetae Bulanova-Zachvatkina, 1967

P. flagellata ( Balogh and Mahunka, 1969) n. comb. (= Metabelba f., = Epidamaeus (Akrodamaeus) flagellatus ) P. golosovae ( Lyashchev et Tolstikov, 1993) n. comb. (= Epidamaeus (Akrodamaeus) g.) P. inaequipes ( Banks, 1947) n. comb. (= Belba i., = Epidamaeus (Akrodamaeus) i.) P. longiseta ( Banks, 1906) n. comb. (= Oribata l., = Epidamaeus (Akrodamaeus) l.) P. m e r i d i a n a ( Norton, 1979) n. comb. (= Epidamaeus (Akrodamaeus) meridianus )

Remarks. As mentioned earlier, Subías (2004, online version 2011) proposed that Damaeus (Heterodamaus) exilior Mihelcic, 1964 belongs to Parabelbella and Heterodamaeus is a junior synonym of this genus. However, original description of the species does not allow to conclude about this synonymy, and for final decision the study of original material is needed. Until confirmation of presence of Parabelbella characters we cannot accept placement of exilior within this genus.

The three European species differ from all American species by the shape of notogastral setae, which are relatively shorter, barbed and usually finely attenuated and distally curled. Setae of American species are quite long and setiform, as found in many other Damaeidae ; setae p 1 may be very long and flagellate, but in all cases the setae are smooth. Both types of setae are found also in other Damaeidae (e.g. within Epidamaeus ), but nevertheless this correlation with geographical distribution may indicate internal relationships among the species from the two regions. Akrodamaeus could potentially be retained at subgeneric rank within Parabelbella , for example, but such an organization seems unnecessary with so few described species in Parabelbella , and any such consideration should await the description of many unnamed species of this genus in North America (Roy A. Norton, pers. comm., 2011). One could speculate that barbed and curled notogastral setae are more derived than smooth setiform setae, but the rules of priority would preclude having a restricted sense of Parabelbella (European species only) as a subgenus within Akrodamaeus . Also, the many movements and strange associations of genus-group taxa in Damaeidae have caused enough confusion, so at present it seems most reasonable to avoid proposals of subgenera and instead consider species-groups whenever finer resolution is needed for discussion.

Parabelbella crenatosetosa and P. g o l o s o v a e are quite similar ( Fig. 12 ), considering how little we know of the former species. Both were found in Central Asia, and both have similar size, similar development of propodolateral apophysis P and a similar sensillus. The notogastral setae show some similarity, except the curled, flagellate tips of P. golosovae are not known to be present in P. crenatosetosa . Such a small detail, together with body surface microsculpture may have been easily overlooked or remained unmentioned by Bulanova-Zachvatkina, so the potential synonymy of the two names cannot be completely excluded. This should be checked in the future, ideally using topotypical material of P. crenatosetosa . For now, we assume that the characters distinguishing P. g o l o s o v a e are not present on P. crenatosetosa .

European species of the Parabelbella can be distinguished with the following key:

1 Larger species, body length over 550 µm. Propodolateral apophysis weakly developed or absent. Notogastral setae longer, reaching the insertion of next posterior setae. Mutual distance of notogastral setae c 1 –c 1 about the same as c 1 –c 2........... 2

- Smaller species, body length under 400 µm. Propodolateral apophysis distinct, well developed. Notogastral setae short, at least in anterior part of notogaster not reaching insertions of next posterior seta. Seta c 1 positioned close to each other, their mutual distance clearly shorter than that of c 1 –c 2................................. P. elisabhetae Bulanova-Zachvatkina, 1967

2 (1) Notogastral setae long and curled at the tip. Body surface with characteristic microsculpture, prodorsum surface regularly granulated, but on notogaster and ventral plate granules forming characteristic, net-like pattern............................................................................................ P. golosovae Lyashchev et Tolstikov 1993

- Notogastral setae short, without long flagellate ends. Body surface without distinct net-like microsculpture............................................................................... P. crenatosetosa Bulanova-Zachvatkina 1967

Figures

FIGURE 12. Reproduced original illustrations of: A – Parabelbella crenatosetosa Bulanova-Zachvatkina, 1967; B – Parabelbella golosovae (Lyaschev & Tolstikov, 1993), n. comb.