A new species of the genus Gaeolaelaps (Acari, Mesostigmata, Laelapidae) from Iran

Abstract The Genus Gaeolaelaps Evans & Till, 1966 is currently one of the largest genera of the family Laelapidae Berlese. The known representatives of this genus are active predators of small invertebrates such as other mites, insect eggs and nematodes. Gaeolaelaps iranicus Kavianpour & Nemati sp. n., was collected from soil and litter in various parts of Iran. The description and figures of this species are given. A key to the Gaeolaelaps species of Iran is provided.


Introduction
The mite family Laelapidae Berlese includes hundreds of species that are free-living predators in soil, as well as many others that have varying degrees of association with other animals, both vertebrates and invertebrates (Faraji and Halliday 2009). The genus Gaeolaelaps Evans & Till is currently one of the largest genera of the family Laelapidae. Some species of this genus, such as Gaeolaelaps aculeifer Canestrini, G. oreithyiae Walter and Oliver, and G. gillespiei Beaulieu, are aggressive predators of nematodes and immature arthropods (Beaulieu 2009, Smiley et al. 2003, Trach 2012, Walter and Moser 2010.

Materials and methods
Mites were collected from various soil and litter samples from different parts of Esfahan, Chaharmahal Va Bakhtiari and Khuzestan provinces in Iran. Mites were extracted from samples using Berlese funnels, placed in lactic acid at 55 °C for clearing and then mounted in Hoyer's medium on permanent microslides. All specimens were examined under a phase contrast microscope. Line drawings were made by use of a drawing tube and figures were performed with Corel X-draw software, based on the scanned line drawings. Seven specimens were used for most characters measurements. All the measurements are given in micrometers (μm). The dorsal setae notation followed that of Lindquist and Evans (1965). The term lyrifissures and pore are used to refer to slit-shaped and circular or oval-shaped cuticular openings, respectively. We have attempted to identify all pore-like structures, but we acknowledge that some may have been overlooked. The holotype and some of the paratypes are deposited in the Acarological Laboratory, Department of Plant Protection, Agricultural College, Shahrekord University Shahrekord, Iran. Some paratypes are deposited in the Senckenberg Museum fur Naturkunde Gorlitz Am Museum 1 02826 Gorlitz Germany and Acarological Laboratory, Department of Plant Protection, Agricultural College, Shahid-Chamran University, Ahwaz, Iran.
Stigma surrounded by short, narrow, pointed stigmatal plate, which extends posteriorly past level of mid-coxae IV (a distance ca. thrice diameter of stigma). Peritremes long, extending to anterior of setae s1. Narrow endopodal platelet present mesad coxae III-IV. Narrow exopodal plate surrounding coxae IV, and small exopodal plate between coxae II-III.
Insemination structures. Not seen.

Male. Unknown.
Etymology. The name of this new species refers to the currently known geographic range of the mite.
Notes. Gaeolaelaps iranicus sp. n. is differentiated by the following combination of characters: small size (330-400 long), the presence of four very long setae on tarsus IV (ad2, ad3, pd2 and pd3), and 36 pairs of dorsal setae, with the absence of PX2 and S1 on the opisthonotal part of the dorsal shield, and the presence of two pairs of r-setae (r6, R5) on soft cuticle, which are considerably shorter than the dorsal shield setae.
The dorsal shield chaetotaxy is not always properly described, especially in older descriptions. However, species with as few as 36 pairs of setae appear to be rare, but some species do lack one pair of PX setae, as found in G. iranicus. Some specimens of G. fishtowni (Ruf and Koehler 1993) appear to lack seta PX3 but this species is larger than G. iranicus (565-653), has thickened spine or spur-like setae on the femur, genu, tibia and tarsus of leg II and tarsus IV, and the dorsal shield is posteriorly attenuated.
G. vanpletzeni (Van Aswegen and Loots 1970) has 38 pairs of setae on dorsal shield, lacking the R series, and has only one pair of PX setae (PX2), while G. iranicus sp. n. has 36 pairs of dorsal setae, with R5 and PX3 present. G. spiniseta (Barilo 1991) has 38 pairs of dorsal setae, with one pair of PX setae (PX2), a larger size (505-525), and with elongate spine-like setae on tarsus IV.
Gaeolaelaps kargi (Costa) has two elongate setae on tarsus IV, S1 and PX2-3 present, the postanal seta as long as the para-anal setae, and lacks elongate setae on genu IV. In contrast, G. iranicus sp. n. has four elongate setae on tarsus IV, lacks S1 and PX2 , the post-anal seta is considerably longer than the para-anal setae, and has two elongate setae (ad1 and pd1) on genu IV.
Gaeolaelaps nolli (Karg) has two elongate setae on tarsus IV, a short peritreme (extending to the middle part of coxae II) and has z3, PX2 and S2, while G. iranicus sp. n. has four elongate setae on tarsus IV, a longer peritreme and lacks z3, PX2 and S2.

Key to the Gaeolaelaps of Iran (females)
* We suspect G. postreticulatus (Xu & Liang) recorded by Montazeri et al. (2011) from Iran is a junior synonym of G. nolli. ** The second author has examined the following materials: Two females, soil, Izeh, Khuzestan province, Iran, 2010.