Philopterus Nitzsch, 1818

Najer, Tomas, Papousek, Ivo, Adam, Costica, Trnka, Alfred, Quach, Van Thi, Nguyen, Chinh Ngoc, Figura, Roman, Literak, Ivan & Sychra, Oldrich, 2020, New records of Philopterus (Ischnocera: Philopteridae) from Acrocephalidae and Locustellidae, with description of one new species from Regulidae, European Journal of Taxonomy 632, pp. 1-37 : 7

Genus Philopterus Nitzsch, 1818

Type species: Philopterus ocellatus (Scopoli, 1764) .

Remarks

Until now, all Philopterus known from both Acrocephalidae and Regulidae were included in so called “ reguli ” species group. This species group was established by Złotorzycka & Lucińska (1976), but their description of the group is very general. It uses formulations which do not enable identification of this group without extensive comparison of large series of material (e.g., “mostly trapezoidal” or “mostly shaped differently than in another groups”). Besides Ph. reguli , the authors place in this group also Philopterus rubeculae ( Denny, 1842) , Philopterus capillatus ( Złotorzycka, 1964) , Philopterus desertus ( Złotorzycka, 1964) , Philopterus pallescens ( Denny, 1842) , Philopterus rutteri ( Kellogg, 1899) , Philopterus modularis ( Denny, 1842) , Philopterus emiliae Balat, 1955 , Philopterus mirificus ( Złotorzycka, 1964) and Philopterus necopinatus ( Złotorzycka, 1964, the two latter species being known from Acrocephalus J.A. Naumann & J.F. Naumann, 1811). In the end of the description they declare identity of the whole group as questionable.

Mey (1983) claims that diagnostic features of this group should be shape of head and anterior dorsal plate, pleural chaetotaxy of abdominal segment IV, chaetotaxy of pronotum and “characteristic features of male genitalia” (without being more concrete). However, in any of these characteristics he does not describe how should they look like to be diagnostic for the species group. He places to this group only Ph. reguli , Ph. pallescens and Ph. rutteri . For Ph. modularis and seven other species ( Ph. emiliae , Ph. rubeculae , Ph. capillatus , Ph. desertus , Ph. davuricae Fedorenko & Volkov, 1977 , Ph. markevichi Fedorenko & Volkov, 1977 and Ph. mugimaki Fedorenko & Volkov, 1977 ), he newly established the modularis species group; however, he does not provide further description of this group. Concerning Philopterus fedorenkoae ( Mey, 1983) , Ph. mirificus and Ph. necopinatus , he states that their relationship to the reguli species group cannot be resolved until examination of more material.

We examined the holotype of Philopterus reguli (NHML). This specimen is morphologically different (e.g., in shape of head, shape of dorsal preantennal head plate, thoracic and abdominal chaetotaxy, shape of subgenital plate) from all other examined Philopterus from Regulidae . Therefore, we hereby pronounce it to be a straggler and below we describe the species infesting Regulidae as a new species, Philopterus gustafssoni sp. nov. We also examined the material on which Złotorzycka & Lucińska (1976) based description of “ reguli ” species group. All these specimens (see below) are in fact Ph. gustafssoni sp. nov., so if the species group exists, it should be rather named gustafssoni species group. Concerning other species of the group, the types of Ph. mirificus and Ph. necopinatus are lost ( Jaloszynski et al. 2014), so we could not assess morphological similarity of these two species and Ph. gustafssoni sp. nov. We tried to contact Eberhard Mey in order to get information about type material of Ph. fedorenkoae and specification of “ reguli ” (now gustafssoni ) species group diagnosis, but without any success. Figures accompanying description of Ph. fedorenkoae ( Mey 1983) show that this species differs from Ph. gustafssoni sp. nov. in several features (e.g., shape of head and dorsal head plate, pronotal chaetotaxy, shape of male subgenital plate), so it does not belong to the species group regardless it exists or not. We can also state that all by us examined Philopterus from Acrocephalus warblers (including those which might be Ph. fedorenkoae , see below) are clearly different from Ph. gustafssoni sp. nov. (see below) and do not form one species group. In other figures provided by Mey (1988), Ph. pallescens , Ph. rutteri , Philopterus hercynicus ( Mey, 1988) and Philopterus peripariphilus ( Mey, 1988) show similar head shape, anterior dorsal plate shape and pronotal chaetotaxy (with more than one pair of pronotal setae) as Ph. gustafssoni sp. nov. This paper, however, does not contain illustrations of male genitalia (except Ph. hercynicus ) and subgenital plates. Therefore, we cannot resolve justification of this species group without extensive revision of Philopterus from Paridae Vigors, 1825 . This revision is currently ongoing and it will be presented in a separate article, so hereby we only state that Ph. acrocephalus does not belong to this species group.