Metabelba (Pateribelba)

Miko, Jan Mourek Ladislav & Bernini, Fabio, 2011, Taxonomy of European Damaeidae (Acari: Oribatida) IV. Partial revision of Metabelba Grandjean, 1936 with proposal of one new subgenus, one new species and redescriptions of two known species, Zootaxa 3099, pp. 1-42 : 5-6

Subgenus Metabelba (Pateribelba) n. subg.

Diagnosis. Metabelba with propodolateral apophysis (P) absent, fully reduced.

Type species. Metabelba sphagni Strenzke, 1950 .

Other included species: Metabelba italica ( Sellnick, 1931) ; Metabelba romandiolae ( Sellnick, 1943) ; Metabelba lanceolata van der Hammen, 1952 (= junior synonym of M. sphagni ; possible synonymy suggested by Miko, 2006 and finaly confirmed in our study); Metabelba platynotus Grandjean, 1954 ; Metabelba ericius Kunst, 1957 ; Metabelba rhodopeia Kunst, 1961 ; Metabelba gladiator Mihelčič, 1963 (= junior synonym of M. romandiolae ; possible synonymy suggested by Bernini et al., 1987 and confirmed in our study); Metabelba filippovi Bulanova- Zachvatkina, 1965; Metabelba flagelliseta Bulanova-Zachvatkina, 1965 ; Metabelba monilipeda Bulanova-Zachvatkina, 1965 ; Metabelba pseudoitalica Bulanova-Zachvatkina, 1965 ; Metabelba paraitalica Kulijev, 1967 ; Metabelba machadoi Pérez-Iñigo, 1986 and Metabelba denscanis n. sp.

All of the listed species are new combinations of Metabelba (Pateribelba) .

Etymology. The prefix " Pateri- " is derived from the Latin masculine noun pater = father. We wish to honor the Croatian acarologist and tardigradologist dr. Franz Mihelčič (1898–1977), who was a catholic priest— pater in Spain and Tyrol ( Austria); see Kofler (1978) for his biography and bibliography. He was the first to propose the grouping of Metabelba species into two subgenera based on the presence or absence of the propodolateral apophysis. Moreover, he was probably the first to collect specimens of M. denscanis n. sp., even if he did not recognize it as a new species (see below).

Species incertae sedis: Damaeus propinquus Sellnick, 1943 ; Metabelba benoiti Balogh, 1958 , Metabelba angolensis Balogh, 1958 ; Metabelba heteropoda Balogh, 1958 ; Metabelba horrida Balogh, 1958 ; Metabelba tanganyikensis Balogh, 1958 .

Remarks. The above species lists are based partly on Subías (2004, 2008, 2009, 2011), who listed 30 named species of Metabelba , including six species marked as " species inquirenda". However, some of the synonymies that he proposed (without explanation) need to be substantiated. Also, the concept of the genus differs according to author (see above), so several previously included species are not members of Metabelba in its current sense. This is the case of Oribata montanus Kulczynski, 1902 , which was considered by several authors (van der Hammen & Strenzke 1953; Sellnick 1960; Kunst 1961; Mihelčič 1964) to be a member of Metabelba due to the presence of companion setae d on tibiae II and III. However, it has a different setation of trochanters (1-1-2-1) and femora (7-6- 4-4) and Miko (2006) recently included this species in Caenobelba Norton, 1979e .

Metabelba craigheadi Jacot, 1939 apparently does not belong to the genus as it was recombined to Epidamaeus by Marshall et al. (1987). The transfer was based on the study of the type specimen and numerous freshly collected specimens (R. A. Norton, pers. comm. 2010). Moreover, Jacot (1939) in the original description of M. craigheadi mentioned the presence of spinae adnatae and figured only one seta on trochanter IV and four setae on femur IV, which is not consistent with the diagnosis of Metabelba .

The taxonomic position of several other species remained uncertain untill now. Sellnick (1943) described two species of Damaeidae from Central Italy (Romagna): Damaeus propinquus and D. romandiolae . The original descriptions are unfortunately brief, lack figures, and do not include details on the leg setation, which are important diagnostic characters at the genus level. Van der Hammen & Strenzke (1953) suggested that both species probably belong to Metabelba . Bernini (1982) also considered romandiolae to be a member of Metabelba , but did not offer a redescription. These opinions seem to have been accepted by Subías (2004, 2008), who included propinquus in Metabelba s. stricto and romandiolae in Metabelba (Parametabelba) , whereas Subías (2009, 2011) listed the former species as Metabelba (Metabelba) propinqua "species inquirenda". We confirm that romandiolae indeed has the characters of Metabelba and transfer it to Metabelba (Pateribelba) n subg., which we support with the detailed redescription presented below. Damaeus propinquus is small, spinae adnatae are absent, and apophysis P is present, which indicates that it might belong to Metabelba s. stricto. Unfortunately, the original description contains no information on the leg setation; therefore, we consider D. propinquus as being a species incertae sedis, until it is thoroughly revised.

Balogh (1958) described five species of Metabelba from tropical Africa, but the descriptions are insufficient and lack figures. In one of these, Metabelba benoiti Balogh, 1958 , the propodosoma is angular between legs I and II, so it might belong to Metabelba s. stricto. In the remaining four species— Metabelba angolensis Balogh, 1958 ; Metabelba heteropoda Balogh, 1958 ; Metabelba horrida Balogh, 1958 and Metabelba tanganyikensis Balogh, 1958 —the propodosoma is rounded between legs I and II, and so they may belong to Metabelba (Pateribelba) n. subg. Unfortunately, Balogh (1958) provided no information on the leg setation in any of the species. Therefore, it is not possible to confirm if the species really belong to Metabelba in its modern sense, so we consider them to be species incertae sedis (see also Subías 2004, 2008, who classified them as " species inquirenda ").

Metabelba pulverosa Strenzke 1953 has been considered by some authors ( Bulanova-Zachvatkina 1965, 1975; Subías 2004, 2008, 2009, 2011) as a junior synonym of " Metabelba pulverulenta " ( C. L. Koch, 1839), which was originally described as Nothrus pulverulentus . However, van der Hammen & Strenzke (1953) documented, that the identity of M. pulverosa and " M. pulverulenta " can be rejected, (based on Oudemans (1937) who reproduced Koch’s description and figures), since the form described by Koch lacks propodolateral apophysis and notogastral setae are inserted more laterally than in M. pulverosa . They supported the hypothesis of Grandjean (1936) that Nothrus pulverulentus C. L. Koch, 1839 is in fact a member of Porobelba Grandjean, 1936 , possibly a senior synonym of P. spinosa ( Sellnick, 1920) . We therefore consider M. pulverosa Strenzke 1953 as a valid species. For further details on this synonymy see van der Hammen & Strenzke (1953) and Miko (2006).

Subías (2009, 2011) included Belba limasetosa Bulanova-Zachvatkina, 1962 in Metabelba s. stricto. In our view, this recombination is unjustified, because Bulanova-Zachvatkina (1962, 1975) figured tibia IV of this species with seta d present, whereas in Metabelba seta d is absent from tibia IV. Metabelba filippovi Bulanova-Zachvatkina, 1965 ; M. flagelliseta Bulanova-Zachvatkina, 1965 ; M. monilipeda Bulanova-Zachvatkina, 1965 ; M. pseudoitalica Bulanova-Zachvatkina, 1965 and M. paraitalica Kulijev, 1967 all lack apophysis P, and so were misplaced in Metabelba s. stricto by Subías (2004; 2008) but were recombined to Metabelba (Parametabelba) by Subías (2009, 2011). In contrast, M. rohdendorfi Bulanova-Zachvatkina, 1965 and M. rara Bulanova-Zachvatkina, 1965 have apophysis P well developed and thus belong to Metabelba s. stricto.

Subías (2009, 2011) synonymised M. paraitalica with M. pseudoitalica , the latter name having priority, but gave no reasons. According to original descriptions, the species are similar, but M. paraitalica differs in having flagellate notogastral seta ps1, apophysis Sa being shorter than Sp and the propodosoma being comparatively long and narrow (see Bulanova-Zachvatkina 1965 and Kulijev 1967). Therefore, we consider M. paraitalica as a separate species, until the type material is studied in detail.

Metabelba orientalis Balogh and Mahunka, 1967 , described from Vietnam, has apophysis P present, which is the diagnostic character of Metabelba s. stricto, but the authors provided no information on leg setation. The study of the holotype, deposited in the Mahunka’s collection in the Soil Zoology Collection in Hungarian Natural History Museum Budapest revealed, that the setation of trochanters and femora strongly differs from other Metabelba species and M. orientalis should thus be recombined to another genus of Damaeidae (Mourek unpubl.). The species will be redescribed in detail in a subsequent paper.

Metabelba flagellata Balogh and Mahunka, 1969 , described from Bolivia, was redescribed and recombined to Epidamaeus (Akrodamaeus) flagellatus by Norton (1979c).

Metabelba glabriseta Mahunka, 1982 , described from Ethiopia, also lacks apophysis P. The author provided no information on leg setation, but according to Ermilov et al (2010), who studied the ontogeny of this species, the species has the leg setation typical for the genus Metabelba . This was also confirmed with the study of the holotype deposited in the Mahunka’s collection (Mourek unpubl.) and the species will be redescribed in a subsequent paper.

Dasybelba aphelesa Woolley and Higgins, 1979 , described from Colorado ( USA), was considered a member of Metabelba s. stricto by Subías (2004, 2008). According to the characters presented in the text and figures of the original description, the species definitely does not belong to Metabelba . Dasybelba Woolley and Higgins, 1979 , as defined in the original description, probably in fact includes species from different genera, their relations with other damaeid genera are uncertain and need further study (R. A. Norton, pers comm. 2009).

At the end of this work we present a tentative diagnostic key for the species of Metabelba (Pateribelba) n. subg., which is based on literature survey and detailed study of available species. Species incertae sedis described by Balogh (1958) are not included in the key.