Amblyseius obtusus ( Koch, 1839 )

Amblyseius obtusus ( Koch, 1839) View in CoL ( fig. 10 View Fig )

Zercon obtusus Koch, 1839: 13 .

Seius obtusus : Berlese, 1889: 7.

Typhlodromus obtusus : Chant, 1957: 306.

Typhlodromus (Amblyseius) obtusus : Chant, 1959: 90.

Amblyseius (Amblyseius) obtusus View in CoL : Muma, 1961: 287.

Amblyseius obtusus View in CoL : 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 View Fig , 1 View Fig ) 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 View Fig , 2 View Fig ) 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 View Fig , 3 View Fig ). The posterior part of the peritremal shield is narrow, slightly curved, and rectangularly cut off at the end ( fig. 1 View Fig , 4 View Fig ). There are 10–11 chelicerae on Df, and 3 on Dm ( fig. 10 View Fig , 5 View Fig ). Spermatheca with a tube-shaped corrugated neck and a small saucer-shaped funnel ( fig. 10 View Fig , 6 View Fig ). Leg IV has 3 long macrochaetes; the longest is on the knee ( fig. 10 View Fig , 7 View Fig ). 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 View Fig , 8 View Fig ). The spermatodactyl is massive, L-shaped, flattened at the end in the form of a rounded “scapula” ( fig. 10 View Fig , 9 View Fig ). 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 View Fig , 6 View Fig ).

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.