Pachylaelaps Berlese, 1888

MAŠÁN, PETER & HALLIDAY, BRUCE, 2014, Review of the mite family Pachylaelapidae (Acari: Mesostigmata), Zootaxa 3776 (1), pp. 1-66 : 30

Genus Pachylaelaps Berlese, 1888

Pachylaelaps Berlese, 1888b: 196 .

Type species Gamasus pectinifer G. Canestrini, 1881 , by subsequent designation ( Berlese, 1904), but see below.

The type species of Pachylaelaps is always said to be Gamasus pectinifer G. Canestrini, 1881 , but that is impossible. The genus name Pachylaelaps was first used by Berlese (1888b, 30 November, date from Poggi, 2008), with two included species, Pachylaelaps haeros Berlese, 1888 and Pachylaelaps athleticus Berlese, 1888 . The type species of the genus must therefore be either P. haeros or P. athleticus . Gamasus pectinifer cannot be the type species of the genus because it was not one of the species originally included when the genus was described (International Code of Zoological Nomenclature, Article 67.2). Only ten days later Berlese (1888a, 10 December) redescribed the genus and added a third species, " Gamase Savignii ", apparently referring to Acarus savignyi Audouin, 1826 . Berlese (1892c) then moved P. haeros and P. athleticus into his new subgenus Pachylaelaps (Megalolaelaps) , and placed G. pectinifer in Pachylaelaps (Pachylaelaps) . This arrangement would make Pachylaelaps (Megalolaelaps) an objective junior synonym of Pachylaelaps (Pachylaelaps) . Berlese (1904) then re-described Pachylaelaps yet again, and stated that its type species was P. pectinifer . That invalid type species designation has been followed ever since. Pachylaelaps haeros and P. athleticus are both now placed in the genus Megalolaelaps , which is the type genus of the family Megalolaelapidae . The use of either of these species as the type species of Pachylaelaps would seriously disrupt the taxonomic concept of the genus, which has been stable for over 100 years. We therefore maintain the current usage of P. pectinifer as the type species of Pachylaelaps in the interest of stability.

Further re-descriptions of Pachylaelaps were provided by Evans & Hyatt (1956), Costa (1971) and Koroleva (1977b). Mašán (2007a) clarified the concept of the genus Pachylaelaps by removing some species that obviously belong in other genera (e.g. Onchodellus , Pachydellus ), and described the new subgenus Longipachylaelaps , which may be easily separated from Pachylaelaps s. str. by the presence of normal needle-like clunal setae J5 (minute microsetae in Pachylaelaps s. str.) and only one pair of hypertrophied slit-like gland openings gdS4 on the posterolateral margin of the dorsal shield (two pairs gdZ1 and gdS 4 in Pachylaelaps s. str.).

Pachylaelaps can be now easily identified by the following characters: (1) sperm access system of females associated with coxae IV ( Fig. 4 ); (2) female tarsus II with two spur-like distal setae, pl1 and pl2; (3) genu I with 13 setae; and (4) tibial projections on male palp present (except for species of Pachylaelaps pectinifer group). It currently comprises up to 60 known species found mostly in the Palaearctic Region, and only rarely in Africa, North America, Australia and South Pacific Islands.

Figures

FIGURES 1–4. Pachylaelapidae species, females, coxae III and IV showing attachment of sperm induction tubes. 1. Onchodellus slovacus; 2. Pachydellus sculptus; 3. Olopachys suecicus; 4. Pachylaelaps longulus. Based on Mašán (2007a).