Description of a new species of Gaeolaelaps (Acari: Laelapidae) from Iran

Abstract A new species of Gaeolaelaps (Acari, Mesostigmata, Laelapidae), Gaeolaelaps izajiensis sp. n. is described based on the morphological characters of adult females which were collected from soil sample in the Izeh and Ghaletol regions of the Khuzestan province, Iran. It can be distinguished from the other members of the genus by some morphological characteristics of dorsal shield, form and reticulation of epigynal shield, the exopodal plates, and the peritremes.


Introduction
Mites of the family Laelapidae are ecologically divers and comprise parasites and predators which found in various habitats (Strong and Halliday 1994, Beaulieu 2009, Lindquist et al. 2009, Nemati and Mohseni 2013. They are good candidates for biological control of the pests which spend time in the soil or other plant growing media (Beaulieu 2009). The family increased in the size with around 90 known genera and more than 1300 species (Beaulieu et al. 2011). Gaeolaelaps is a large cosmopolitan genus of the Laelapidae family which consists of more than 100 described species Mohseni 2013, Kazemi et al. 2014). Different types of the habitats were reported for the Gaeolaelaps mites including: soil, litter, nests and bodies of vertebrates and invertebrates (Bregetova 1977, Beaulieu 2009, Lindquist et al. 2009, Trach 2012. Gaeolaelaps species are typically known as small invertebrate predators, and collected from the bodies and nests of many arthropods including cockroaches, termites, mole crickets, beetles, ants, millipedes and mygalomorph spiders (Bregetova 1977, Rosario 1981, Tenorio 1982, Strong and Halliday 1994, Fain et al. 1995, Strong 1995, Beaulieu 2009, Faraji and Halliday 2009. Twenty species of Gaeolaelaps have been reported from Iran of which nine were described as new for science , Nemati and Mohseni 2013, Kazemi et al. 2014, Kavianpour and Nemati 2014, Vatankhah et al. 2016. It is noticeable that the majority of these species (seven species) have been collected from soil , Nemati and Mohseni 2013, Kazemi et al. 2014, Kavianpour and Nemati 2014, one species (Vatankhah et al. 2016) has been described from the nest of Formica sp. (Hymenoptera: Formicidae) and one species from the body of a carabid beetle, Acinopus sp. (Coleoptera: Carabidae) which the later had been previously excluded from Gaeolaelaps by Kazemi et al. (2014). Four of these species including G. farajii Nemati & Mohseni, 2013;G. jondishapouri Nemati & Kavianpour, 2013;G. khajooii Kazemi, Rajaei &Beaulieu, 2014 andG. orbiculatus Nemati &Mohseni, 2013 were reported from the south of Iran (Khuzestan and Kerman provinces) while one species (G. ahangarani Kazemi & Beaulieu, 2014) has been described from the north (Mazandaran province) and three species (G. iranicus , G. mossadeghi Kavianpour & Nemati, 2013and G. lenis Vatankhah & Nemati, 2016 from the central part of Iran (Esfahan province). Here a further new species is described, which will be the tenth species from Iran; it was collected from the soils of Izeh and Ghaletol, Khuzestan province, Iran.

Materials and methods
Gaeolaelaps specimens were extracted from soil samples using Berlese funnels, placed in lactic acid at 55 °C for clearing and then mounted in Hoyer's medium as permanent microslides for microscopic examination. Taxonomically relevant structures of this species were illustrated with the use of a drawing tube and figures were performed with Corel X-draw software, based on the scanned line drawings. Measurements of structures are expressed as minimum-maximum ranges in micrometers. The dorsal setae notation, leg and palp chaetotaxy follows that of Lindquist and Evans (1965), Evans (1963a, b) and Evans and Till 1965 respectively. Terminology for idiosomal glands and lyrifissures follows Kazemi et al. (2014). Legs were measured dorso-medially excluding the stalk and pretarsus.
The genus definition of Kazemi et al. 2014 was followed (see notes in discussion).

Diagnosis (adult female).
Dorsal shield with constriction at lateral margins near setae s6 and distinct reticulation posterior to j6 along with line reticulation in lateral margins of podonotal part, possesses 39 pairs of simple thin acicular setae; sternal shield with reticulation in lateral regions, epigynal shield with elongate and nearly quadrangle cells and abutting anal shield, exopodal plates fragmented between coxae II and IV; peritremes relatively long and extending to the posterior margin of coxae I.
Ventral idiosoma (Fig. 2). Base of tritosternum 25-30 long, 7-10 wide (at basal level), pilose laciniae free for 59-73 and fused basally for 7-9. Pre-endopodal area granulated, with a pair of slightly sclerotised pre-sternal plates. Sternal shield 120-127 long (along midline from anterior edge to its posterior margin), 98-110 wide (at level of projection between coxae II-III) and 81-88 at level of st2, smooth in median region and posterior part and reticulated in lateral margins, with distinct anterior and posterior margins, posterior margin irregular. Sternal setae smooth, st1-st3 (20-23), iv1 slit-like, located slightly behind st1, iv2 pore-like, between st2-st3. Setae st4 (16-19) and pore-like iv3 located on integument behind posterior margin of sternal shield.  Reticulate tongue-shaped epigynal shield with elongate and nearly quadrangle cells, 171-180 long at midline from anterior margin to posterior level and abutting anal shield, 73-83 wide at epigynal setae, ratio of length to width (L/W) 2.14-2.4, with one pair of simple acicular setae (st5 = 18-20). Paragenital pores (iv5) on soft integument posterior to epigynal setae, between epigynal margin and coxa IV. Anal shield subtriangular, reticulated, 54-60 long (at midline from the anterior margin to the posterior edge of the cribrum), 54-56 wide (at widest point), post anal seta (14-15) nearly equal to para-anal setae (15-17). Cribrum thin and extending posterolaterally to the level of post-anal seta insertion. Opisthogastric surface with: one pair of narrow and slightly elongate paragenital platelets; one pair of suboval metapodal plates (24-26×10-12); one pair of minute platelets between paragenital and metapodal plates; eight pairs of smooth acicular setae: Zv1-3 and Jv1-5; and five pairs of pore-like structures, plus para-anal gland pores gv3 on lateral margins of anal shield. Jv2 located on soft opisthogastric cuticle at postero-lateral part of epigynal shield (Fig. 4). In holotype this part of soft cuticle bent down and Jv2 appeared on anterior margin of anal shield as shown in Figures 2 and 5. Stigma located at anterior level of coxa IV. Peritremes narrow and long, extending anteriorly to posterior margin of coxae I with fusing at posterior margin of sub-triangular accessory shield, peritrematal plate wider in middle part, and with one glandular poroid gp and one lyrifissure ip (Fig. 3), separated from exopodal shield. Poststigmatal plate narrow and with two pore-like structures. Exopodal II-III small and subtriangular, along with two fragmented platelets at posterior part of coxa III. Exopodal III-IV narrow, angular and reached to the tip of endopodal III-IV at posterior level of coxa IV. Endopodal plates II/III incorporated to lateral margins of sternal shield, III-IV strip like extending to the posterior margin of coxa IV.
Insemination structures. Not seen.

Male. Unknown.
Etymology. The name of the new species refers to Izaj, the ancient name of Izeh (a town in Khuzestan province, southwest Iran) where the holotype was collected.
Remarks. Gaeolaelaps izajiensis sp. n. is differentiated from all other members of the genus by the following combination of characters: dorsal shield with constriction at lateral margins near setae s6, with 39 pairs of simple thin acicular setae; reticulated epigynal shield with elongate and nearly quadrangle cells and abutting anal shield, exopodal plates fragmented between coxae III and IV; peritremes long and extending to the posterior margin of coxae I. Some species of Gaeolaelaps genus have long epigynal shield like: G. loksai (Karg, 2000), G. pinnae (Karg, 1987) and G. macra (Karg, 1978) in which the epigynal shield extending near anal shield with only one pair of opisthogastric setae between epigynal and anal shields. Gaeolaelaps macra and G. loksai have short peritremes which extended to near anterior and middle level of coxa II, respectively. Gaeolaelaps pinnae has long peritreme extending to anterior part of coxa I but has long dorsal setae which exceed the base of successive setae in series, seta J1 and some other opisthonotal setae barbed distally and iv2 slit-like (Karg 1978(Karg , 1987(Karg , 2000.

Discussion
Gaeolaelaps has been defined in details by Beaulieu (2009) andKazemi et al. (2014). The new species described in this paper is well accordance with definition of Kazemi et al. (2014) except for the characteristic no. 10 (p. 504). They stated that epigynal shield tongue or flask-shaped, not markedly broadened posteriorly, bearing one pair of simple setae, and not touching anal shield.
In some species of this genus (G. loksai (Karg), G. pinnae (Karg) and G. macra (Karg)) epigynal shield extending near subtriangular anal shield in which there is only one pair of opisthogastric setae between these two shields, but in fact none of Gaeolaelaps species has epigynal shield abutting subtriangular anal shield. Our new species has epigynal shield uniquely long and extended to the anal plate with one pair of setae (Jv2) located at posterior latero-corners of epigynal shield on unsclerotised cuticle of opisthogasteric area. In this paper, we have followed the definition of Kazemi et al. (2014) to consider our new species as a member of Gaeolaelaps with the following modification to the no. 10 characteristic (length of epigynal shield): 10. Epigynal shield tongue-or flask-shaped, not markedly broadened posteriorly, bearing one pair of simple setae, and not touching anal shield in most of the species except for G. izajiensis n. sp.