Alloseius pratensis (Karg)

Mašán, Peter & Halliday, Bruce, 2010, Review of the European genera of Eviphididae (Acari: Mesostigmata) and the species occurring in Slovakia 2585, Zootaxa 2585, pp. 1-122 : 36-39

Alloseius pratensis (Karg)

( Figs 19–33, 92, 96, 97, 104)

Iphidosoma pratensis Karg, 1965: 263 ; 1971: 121; 1993: 94; Bregetova, 1977a: 561 .

Alliphis montanus Koroleva, 1968: 1727 ; Mašán, 1994a: 18. New synonymy.

Alliphis pratensis .⎯ Kethley, 1983: 2599.

Alliphis rotundianalis Mašán, 1994a: 12 . New synonymy.

Alliphis stenosternus Gu & Liu, 1996: 300 , in part, male and deutonymph only, not female holotype, misidentification. Scarabaspis altaicus Sklyar, 1999: 109 . New synonymy.

Amendments to diagnosis (adults and deutonymph). Female ( Figs 19, 20, 23, 25, 26, 28–30, 104).

Dorsal idiosoma ( Fig. 19). Idiosoma 425–535 µm long and 315–380 µm wide. Dorsal shield 395–465 µm long, 300–335 µm wide. Dorsal setae heterogeneous in length, sublateral setae longest, often with hyaline extensions ( Fig. 26), 30–40 µm long, approximately double length of some short central setae. Vertical setae j1 columnar, extremely short, 6–12 µm long; setae j5 20–26 µm long. Posterior dorsal setae J5 and Z5 usually modified, short, thick, apically rounded, columnar or rod-shaped; setae J5 8–11 µm long, Z5 13–18 µm long.

Ventral idiosoma ( Fig. 20). Sternal shield smooth, without ornamentation on surface, anterolateral and mediolateral corners pointed, shield 81–91 µm long and 55–66 µm wide at narrowest point; sternal setae short, simple, needle-like, 13–17 µm long. Epigynal shield 41–58 µm wide, widest at level of genital setae, delicately striate; striae short, irregular, longitudinal. Anal shield striate and punctate on surface, 109–119 µm in width; post-anal seta thicker than adanals. Soft opisthogastric integument with ten pairs of setae.

Male ( Figs 21, 22, 92, 96, 97). Dorsal idiosoma ( Fig. 21). Dorsal shield 320–370 µm long and 195–230 µm wide, with some anterolateral longitudinal sculptural lines. Dorsal setae heterogeneous in length, anterior and marginal setae approximately double length of central setae; J3 and J5 short, thick; j1 16–18 µm, j4 21–27 µm, j5 10–14 µm, J3 and J5 5–8 µm, Z5 9–12 µm.

Ventral idiosoma ( Fig. 22). Sterno-genital shield 140–165 µm long, surface smooth. Opisthogastric integument with three pairs of post-genital sclerites and a pair of large elongate metapodal platelets. Anal shield large, subcircular, slightly wider than long, 68–76 µm long and 69–86 µm wide, transversely striated in anterior part. Peritrematal shields relatively wide, well developed along the whole peritreme, with a pattern of longitudinal lines ( Fig. 92); post-stigmatic section wide, short and usually tapered posteriorly.

Deutonymph ( Figs 24, 27, 31–33). Dorsal idiosoma ( Fig. 32). Idiosoma dorso-ventrally flattened, suboval. Dorsal shield 330–385 µm long and 225–260 µm wide, entire, covering whole dorsum, bearing 30 pairs of setae and delicate net-like surface pattern. Dorsal setae relatively short, especially in central area, simple and needle-like, only vertical setae j1 slightly stouter, lance-like; z1 minute, in ventral position.

Ventral idiosoma ( Figs 24, 33). Presternal platelets absent. Sternal shield well sclerotised, relatively large, 140–165 µm long, with short longitudinal marginal striae, anterior margin undulating, posterior end tapered and rounded, bearing four pairs of setae and three pairs of pores; first pair of pores slightly elongate, slit-like, oriented transversely. Endopodal platelets II–III connected to sternal shield anteriorly, and to endopodals III– IV posteriorly; endopodal platelets with rounded outer margins. Sternal setae st5 inserted in soft integument close to posterior margin of sternal shield, between coxae IV. Opisthogastric integument with three pairs of minute post-genital sclerites and a pair of narrow curved metapodal platelets. Anal shield relatively wide, suboval, slightly wider than long, 66–80 µm long, 71–83 µm wide, weakly striate, bearing relatively small anus and three subequal needle-like circum-anal setae; cribrum well developed, relatively wide and almost truncate on posterior margin. Exopodal platelets I–III absent, exopodals IV present, narrowed and curved. Peritrematal shields developed along the medial and posterior parts of peritremes, slightly widened close to stigmata; peritremes well developed, anterior ends reaching well beyond coxae I; post-stigmatic pore small, distinct. Sexual dimorphism of ventral chaetotaxy well developed: female deutonymph with more setae on lateral and opisthogastric soft integument than male deutonymph; lateral and opisthogastric soft integument with ten pairs of setae in female deutonymphs, eight pairs of setae in male deutonymphs (excluding st5 setae inserted also in soft integument); all ventral setae simple, short and needle-like.

Gnathosoma . Cheliceral segments and digits relatively stout and robust ( Figs 31, 33). Epistome as in Fig. 27.

Remarks. This species described under the name Iphidosoma pratensis by Karg (1965) was transferred into the genus Alliphis by Kethley (1983), and was then designated as the type species of the new genus Alloseius by Mašán & Halliday (2009a). Subsequently, we have obtained rich collections of this species from fresh cow dung pads, with all adult and developmental stages now available. The morphological differences between the adult males and females are so strong that they were described as different species. The males and/or deutonymphs were described as a following species: Alliphis montanus by Koroleva (1968), Alliphis rotundianalis by Mašán (1994a), Alliphis stenosternus by Gu & Liu (1996), and Scarabaspis altaicus by Sklyar (1999). Strong sexual dimorphism is common in various genera of Eviphididae , including Crassicheles , Neocrassicheles , Thinoseius , and Uroiphis . In A. pratensis , the sexual dimorphism is also visible in the deutonymphs. Male adults and male deutonymphs have eight pairs of setae in the lateral and opisthogastric integument ( Fig. 22), while female adults and female deutonymphs have ten pairs ( Figs 20, 24). Males and deutonymphs of Alloseius pratensis have been mostly classified in the genus Alliphis . However, the position and shape of their first pair of sterno-genital pores in this species are not typical for the genus Alliphis . Males and deutonymphs of A. pratensis are relatively common on various dung beetles (Scarabaeoidea), but the absence of females in phoretic populations is another phenomenon atypical of Alliphis (females are common in cow and horse dung pads).

In the original description of Alliphis rotundianalis from Slovakia by Mašán (1994a), the main character for distinguishing this species from Alliphis montanus was based on the specific form of the anal shield in the male. Unfortunately, Koroleva (1968) did not accurately illustrate correct shape of the male anal shield, and her statement of exceptional form of the anal shield, unusual among the all other congeners, was overlooked.

The male anal shield after Koroleva is subtriangular, not subcircular. Both species are conspecific in all other morphological features given for male and deutonymph by Koroleva.

This species seems to be Palaearctic in range, reported from Germany, Slovakia, Ukraine, Russia and China. We have examined further collections from Italy and France (unpublished material).

Occurrence in Slovakia. (a) Verified published data. Považský Inovec Mts.: Lúka [7373] ( Mašán 1994a). Trnavská Pahorkatina Wold: Brunovce [7373] ( Mašán 1994a).

(b) New data. Borská Nížina Lowland: 21 ♀♀, 30 ♂♂, 52 DN, 23 May 2009, Veľké Leváre [7468]. Malé Karpaty Mts. : 4 ♀♀, 12 ♂♂, 33 DN, 9 May 2009, Bratislava , zoopark [7868]. Muránska Planina Plateau: 1 ♂, 20 May 2002, Muráň, Nemecké Lúčky ( Hister sp. ) [7286]; 1 ♂, 3 DN, 20 May 2002, Muráň, Nemecké Lúčky ( T. vernalis ) [7286]; 2 ♂♂, 1 DN, 20 May 2002, Muráň, Nemecké Lúčky ( A. stercorosus ) [7286]. Po ľ ana Mts.: 2 ♂♂, 3 DN, 17 August 1997, Hriňová, Zadná Poľana [7382]. Považský Inovec Mts.: 36 ♀♀, 23 ♂♂, 77 DN, 5 PN, 14 L, 3 May 2009, Modrová [7373]. Slovenský Kras Karst: 6 ♂♂, 6 DN, 28 July 1992, Silica [7489]. Ve ľ ká Fatra Mts.: 4 ♂♂, 2 DN, 21 July 2004 Liptovské Revúce [7081] .