Arctoseius Thor 1930

• Main Authors: Makarova, Olga L., Huhta, Veikko
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2017
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Arachnida; Mesostigmata; Ascidae; Arctoseius; Chukotka; Fennoscandia; Siberia
• Online Access: https://doi.org/10.5281/zenodo.6024014; http://treatment.plazi.org/id/FA6587FFFF85FF8E6B94FE5CFA71D6EE

Key to species of Arctoseius Thor, 1930 of Fennoscandia, North-Western Europe The key is mainly based on females, but reliable identification often requires investigation of males. Total length refers to length of dorsal shield. 1. Gnathotectum biramous; incisions of dorsal shield very deep, their length about 1/3 of dorsal shield width; tibia IV with six setae; peritremes not extending anteriorly beyond mid-level of coxae II; in female sternal shield weakly sclerotized, lacking endopodal elements, nearly rectangular. 2 - Gnathotectum triramous; incisions of dorsal shield shorter or absent; tibia IV with seven setae (exception A . sexsetus ); peritremes of different length; sternal shield with or without angular extensions formed by endopodal elements between coxae I–II and II–III. 4 2. Dorsal shield setae longer, most of them extending to base of next posterior seta in series, seta Z2 reaching or surpassing insertion of Z 3; opisthogastric soft integument with eight pairs of ventral setae ( ZL 3 absent); fixed digit of chelicera with 3–4 teeth; in male, dimorphically modified seta on telotarsus II absent. Female 350–420 µm, male 270–310 µm. Cosmopolitan. semiscissus (Berlese, 1892) - Dorsal shield setae shorter, most of them not extending to base of next posterior seta, seta Z2 not reaching insertions of Z 3; opisthogastric soft integument with nine pairs of ventral setae ( JL 1– JL 5, ZL 1– ZL 4); fixed digit of chelicera with six or more teeth; in male, one ventral seta on telotarsus II swollen basally, with sharply curved hair-like tip. 3 3. Epigynal shield usually with posterolateral margins abruptly expanded beyond the genital setae; fixed digit of female chelicera with six teeth (in male, 10–12 teeth); in general larger species. Female 350–420 µm, male 300–310 µm. European Arctic, Siberia, Chukotka. nikolskyi Makarova & Petrova, 1992 - Epigynal shield usually with almost parallel or gradually divergent posterolateral margins beyond the genital setae; fixed digit of adult chelicera with 7–11 teeth; in ...