Pachyseius angustus Hyatt 1956, sp. nov.
Creators: name: Babaeian, Esmaeil
name: Mašán, Peter
name: Saboori, Alireza
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Mesostigmata
Pachylaelapidae
Pachyseius
Pachyseius angustus

description: Pachyseius angustus Hyatt, 1956 [sensu Babaeian & Kazemi (2011)]
Pachyseius angustus was originally described on the basis of two females from the British Isles. Subsequently, it has been recorded in the literature from Western Europe (Skorupski & Luxton, 1998; Ducarme et al., 2004). This species was reported as new to Iranian by Babaeian & Kazemi (2011), based on a female specimen found in an unspecified substrate of a sandy riverbank. In their paper no additional information on its morphology and identity was providded. Recent examination of the Iranian specimen, and study of holotype of Pachyseius angustus provided by one of us (Mašán, 2007; p. 211), has led to the conclusion that the material from Iran is not conspecific with that of the original type series of Hyatt (1956). Comparisons of shape and arrangements of ventral shields, and setation of scutal and soft integument in both species leave little doubt that close relationship exists. They are very similar in the arrangement of the shield elements of peritrematal-exopodal complex (peritrematal shields are free from adjacent exopodal shields, with terminal end reaching slightly beyond posterior margin of coxae IV, and inner margin abutting to exopodal shields; exopodal shields II–III and III–IV are separate and contiguous to each other), and the chaetotaxy of the ventrianal shield and soft integument (ventrianal shield bearing two pairs of pre-anal setae, soft integument with 11 pairs of setae). There is no doubt the two species may readily be confused with each other.
The holotype specimen of Pachyseius angustus has recently been examined by Mašán (2007), who added some complementary characters and metric data to the original description of Hyatt (1956). The Iranian species may be distinguished from P. angustus by the following female characters: (1) genital pores placed on soft integument, off the epigynal shield (placed on posterolateral angles of the shield in P. angustus); (2) post-stigmatic section of peritrematal shields terminally truncated (tapered in P. angustus); (3) exopodal shields III–IV relatively narrower, as wide as terminal section of peritrematal shields (relatively wider in P. angustus, about several times wider than narrowed terminal section of peritrematal shields); (4) broader species, with idiosoma widely suboval (P. angustus is markedly narrower species, with idiosoma oblong); (5) sternal, epigynal and ventrianal shield with compact reticulation on their surface (in P. angustus, compact reticulate pattern developed only on anterior part of sternal shield, excluding three parallel, curved and about transversely oriented striae on ventrianal shield); (6) tarsus II with one largely expanded spur-like seta (with three spur-like setae in P. angustus). The Iranian specimen appears to belong to an undescribed species of Pachyseius, but we do not have enough material to allow a full description.
description: Published as part of Babaeian, Esmaeil, Mašán, Peter & Saboori, Alireza, 2016, The genus Pachyseius Berlese, 1910 in Iran (Acari: Pachylaelapidae), pp. 420-428 in Zootaxa 4088 (3) on pages 424-426, DOI: 10.11646/zootaxa.4088.3.7, http://zenodo.org/record/261246