Halolaelaps orientalis (Blaszak and Ehrnsberger, 1998)

Halolaelaps orientalis Ishikawa, 1979 (? = Halolaelaps schusteri

Hirschmann, 1966)

A Palaearctic species ranging from the Canary Islands to Japan. There are no records from the shores of the Arctic Ocean, Bering and Okhotsk seas. This species was previously listed as the most common member of the celticus -group on the shores of the northern and southern seas of continental Europe, as well as the Canary Islands ( Błaszak and Ehrnsberger 1998).

Since an error in the original description of Halolaelaps schusteri (structure of setae j 1, z 1) has been corrected during the analysis of the type material ( Błaszak et al. 2004, p. 2), there are no characters left allowing us to securely distinguish between females of H. schusteri and H. orientalis ( Błaszak and Ehrnsberger 1998) . Therefore, all records of “ H. orientalis ” in the Western Palearctic ( Błaszak and Ehrnsberger 1998 ; Avdonin 2002 ; Avdonin and Striganova 2004 ; Maslov 2013 ; Bizin and Makarova 2022) probably belong to H. schusteri , as possibly does the record from Japan as well. The male of H. orientalis has not been described yet. Having analyzed its morphological structures, these two species are highly likely to be synonyms. In marine debris, H. orientalis forms “quasi-stationary aggregations” ( Avdonin and Striganova 2004). In six districts of the Atlantic coast, including the Canary Islands, this species has been noted to live together with H. celticus ( Błaszak and Ehrnsberger 1998) . The dispersion of H. orientalis with floating algae is possible ( Avdonin 1999). It feeds actively on nematodes and copepods (Copepoda) ( Avdonin and Striganova 2004); the consumption of damaged enchytraeids and dipteran Sphaeroceridae (larvae and adults) was also recorded ( Avdonin 1999, 2002).

Morphological diagnostics of Halolaelaps species belonging to the celticus -group in general [the subgenus Halolaelaps (Halolaelaps) sensu Błasczak and Ehrnsberger 1998 ] are greatly hampered by the uncritical attitude of the above authors to the asymmetry and intra-population variability of the dorsal idiosomal chaetome. Such cases were revealed by various researchers ( Maslov 2013 ; O.L.M.: personal observations), including Błasczak and Ehrnsberger (1998,

p. 165, 167) themselves, thus leading to doubt the validity of the species they described (Błasczak and Ehrnsberger 1997, 1998).