First record of the genus Paragigagnathus Amitai and Grinberg, 1971 (Mesostigmata: Phytoseiidae) from Saudi Arabia with description of a new species

Abstract The genus Paragigagnathus Amitai and Grinberg (Acari: Phytoseiidae) is reported for the first time from Saudi Arabia. Paragigagnathus desertorum (Amitai and Swirski) and P. insuetus (Livshitz and Kuznetsov) were collected from Acacia sp. (Fabaceae) and Tamarix sp. (Tamaricaceae), respectively. Paragigagnathus madinaensis n. sp. is described and illustrated. The new species was found on Tamarix sp. in association with Obdulia daadi Al-Gboory (Prostigmata: Tenuipalpidae) from Al-Riyadh and Al-Madina regions of Saudi Arabia.

The genus Paragigagnathus was first placed in the subfamily Gigagnathinae Wainstein. Kolodochka (1994) transferred it to subfamily Amblyseiinae and tribe Amblyseiini Muma on the basis of dorsal setal pattern. After that, it was placed in the tribe Neoseiulini Chant and McMurtry because of cheliceral morphology, dorsal setal pattern and shape of female ventrianal shield (Chant and McMurtry 2003). Chant and McMurtry (2007) divided the genus Paragigagnathus in two species groups, desertorum and strunkovae, based on the position of sternal shield setae ST 3 (on or off the sternal shield). However, in some species this character is not distinctive (Chant and McMurtry 2007;Hajizadeh et al. 2010). A key to the eight valid species of this genus was created by Hajizadeh et al. (2010). They separated the species based on the following morphological characters: length and shape of dorsal setae, most of dorsal setae either with or without tubercles, sternal setae ST 4 on the soft cuticle or on metasternal shields and number of teeth on moveable digit.
Phytoseiid mites are poorly investigated in Saudi Arabia, and to date only 19 species are known (Dabbour and Abdel-Aziz 1982;Fouly and Al-Rehiayani 2011;Al-Atawi 2011a, 2011bNegm et al. 2012aNegm et al. , 2012b. This paper presents the first record of the genus Paragigagnathus from Saudi Arabia, with description of a new species P. madinaensis n. sp. and two new records, P. desertorum (Amitai and Swirski) and P. insuetus (Livshitz and Kuznetsov).

Materials and methods
Three regions of Saudi Arabia, Al-Riyadh, Al-Madina and Al-Baha, were surveyed for the collection of Phytosiid mites during the years 2012-2014. Two collection methods were used: (1) different plant parts were shaken over a white paper and the mites were transferred using a camel hair brush into 70% alcohol; (2) Tullgren funnels were used to extract mites from plant materials. The collected mite specimens were cleared in Nesbitt's fluid for 10-12 h. Subsequently, the specimens were mounted on slides in Hoyer's medium, and dried in oven at 40°C for 1 week. The mounted specimens were examined under a phasecontrast microscope (DM2500, Leica®, Germany). Template illustrations were either drawn with pencil by using a drawing tube (Olympus®, Japan) attached to the microscope, or different body parts of mites were pictured with an Auto-montage Software System (SYNCROSCOPY ® , Cambridge, UK) attached to the microscope. Final processing of drawings was done in Adobe Illustrator (Adobe Systems Incorporated, USA). The terminology used in this study follows that of McMurtry (2003, 2007). All measurements are given in micrometers. Holotype and eight paratypes of new species are deposited at the King Saud University Museum of Arthropods (KSMA) and Acarology Laboratory, Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University. One paratype (P1-accession no. Acy: 15/04) is deposited at the Agriculture Research Council, Plant Protection Research Institute, Pretoria, South Africa (ARC-PPRI). Amblyseius (Amblyseius) Ueckermann andLoots 1988: 118. Pamiroseius Wainstein 1973: 954;Kolodochka 1989: 221;McMurtry 2003: 39. Phytocerus Amitai andSwirski 1978: 124;McMurtry 2003: 39. Phytodromus Muma, Denmark 1993: 107. Paragigagnathus madinaensis n. sp. (Figures 1, 2) Female (Figures 1, 2). n = 16, the measurements of holotype followed by those of 15 paratypes (female) in parenthesis. Dorsal Idiosoma (Figure 1

Spermatheca
Vesicle is saccular, calyx thick, dish shaped, with annulated neck, atrium not adjacent to the calyx, major duct thick and long, minor duct not visible ( Figure 2C).

Chelicerae
Fixed digit with three small apical teeth and a pilis dentilis; movable digit with one subapical blunt tooth ( Figure 2D).

Etymology
The specific epithet 'madinaensis' refers to the city name 'Madina' where some paratypes of the new species were collected.   (Wainstein, 1973) by dish-shaped calyx of spermatheca and 3 pairs of preanal setae, while calyx of spermatheca is funnel shaped and preanal setae 2 pairs in later species.

Spermatheca
Vesicle is saccular, calyx, dish shaped, not very thick, atrium not adjacent to the calyx, major duct long, thick, minor duct not prominent.

Chelicerae
Fixed digit with one bifid tooth and a pilis dentilis; the movable digit smooth.

Spermatheca
Vesicle is saccular, calyx, dish shaped, thick, atrium not adjacent to the calyx, major duct long, thick, minor duct not prominent.

Chelicerae
Fixed digit with one tooth and a pilis dentilis; the movable digit with tooth.