Amblyseius obtusus
Creators: name: Kolodochka, L. O.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Mesostigmata
Phytoseiidae
Amblyseius
Amblyseius obtusus

description: Amblyseius obtusus (Koch, 1839) (fig. 10)
Zercon obtusus Koch, 1839: 13.
Seius obtusus: Berlese, 1889: 7.
Typhlodromus obtusus: Chant, 1957: 306.
Typhlodromus (Amblyseius) obtusus: Chant, 1959: 90.
Amblyseius (Amblyseius) obtusus: Muma, 1961: 287.
Amblyseius obtusus: Ghiliarov et al., 1977: 235; Kolodochka, 2006: 229.
M a t e r i a l. Type. Germany (?), from “gardens, meadows and bank of stream and pool” (cit.: Demite et al., 2024), (collection date and No. of the specimen unknown; not located; not examined).
Non-type. 54 specimen (45 F, 6 M) — Autonomous Republic of Crimea, Cherkassy, Chernihiv, Kyiv, Mykolaiv, Ternopil, Transcarpathian Regions.
R e d e s c r i p t i o n. F e m a l e. The dorsal shield (fig. 10, 1) is well sclerotised, with a dark wmarginal border, smooth, broadly oval, the lateral notches are not pronounced; 7 pairs of solenostomes, of which ic are the largest (it, iv, id, isc, il, is, ic). Setae AD1, AM1 of moderate length; AL4, PM2 are long, PM3 are very long, whip-shaped, the rest are microchaetes. Seta AM1 equal to or slightly longer than the distance to the theca of seta AL1. Seta PM3 approximately equal to width of dorsal shield at level of setae D4. Peritremes extend beyond thecae AD1. The ventroanal shield (fig. 10, 2) is somewhat wider than the genital shield, rounded-pentagonal; anal pores are small and round. The posterior metapodal shield is elongated-oval, no less than twice as long as the linear anterior one (fig. 10, 3). The posterior part of the peritremal shield is narrow, slightly curved, and rectangularly cut off at the end (fig. 1, 4). There are 10–11 chelicerae on Df, and 3 on Dm (fig. 10, 5). Spermatheca with a tube-shaped corrugated neck and a small saucer-shaped funnel (fig. 10, 6). Leg IV has 3 long macrochaetes; the longest is on the knee (fig. 10, 7). Genu and tibia III, genu II and I also with macrosetae, but shorter.
Measurements: Lds 405, Wds 290; Lvas 125, Wvas 110, Lian 33, Ltar 128; setae length: AD1 28; AD2 6; DD3 6; D4 6; PD2 8; PD4 8; AM1 33; AM2 6; AL1 8; AL2 8; AL3 90; PL1 13; PL2 11; PL3 10; PM1 8; PM3 140; PM4 280; AS 11; PS 8; PV 100; MChIV: ge 110, ti 90, ta 75, MChIII: ge 40, ti 54, MChII: ge 38; MChI: ge 36.
Male. Preanal setae 3 pairs; anal pores are round (fig. 10, 8). The spermatodactyl is massive, L-shaped, flattened at the end in the form of a rounded “scapula” (fig. 10, 9). Lds — 310.
D i f f e r e n t i a l d i a g n o s i s. Females of A. obtusus differ from the other species of the genus by the longest dorsal setae of the PM4 pair (280 μm). The characteristic shape and structure of the spermatheca also serves as a reliable distinguishing feature of this species (fig. 10, 6).
D i s t r i b u t i o n, h a b i t a t, o c c u r r e n c e. Europe (20 countries), South Caucasus (Azerbaijan, Armenia), North Africa (Tunisia), Western Asia (Iran, Turkey), North America (Canada), Hawaii, southwestern Pacific Ocean (New Zealand), South America (Venezuela). In Ukraine: Wood-and-Steppe, Steppe, Polissia, Transcarpathia, Crimea (yayla on Main ridge), prefers herbaceous plants with low-lying rosette leaves or lying on the ground, occasionally found on trees, incl. conifers; common.
Notes. The holotype of this species has been lost, but judging by repeated redescriptions and images on material from various countries, it is quite widespread and well known as a species that does not cause controversy in assessing its independence.
Description, morphometry and illustrations are based on non-type specimens from the Kyiv Region after comparing them with voucher specimens from the collection of B. A. Wainstein and illustrations of this species in publications by various authors.
description: Published as part of Kolodochka, L. O., 2024, Predatory Mites (Parasitiformes, Phytoseiidae) Of The Fauna Of Ukraine: Review Of The Genus Amblyseius With A Key To Species, pp. 461-496 in Zoodiversity 58 (6) on pages 481-483, DOI: 10.15407/zoo2024.06.461, http://zenodo.org/record/14704320