New records of phytoseiid mites from Italy, with description of a new species and a redescription of other two (Parasitiformes, Phytoseiidae)

The Italian phytoseiid fauna consists of 91 valid species. Eighteen of them were described as new species from materials collected in various Italian localities. In the present paper we report nine new records from the Italian fauna and describe the new species, Neoseiulus mediterraneus belonging to the subfamily Amblyseiinae. Complementary descriptions of two rare species, namely: Typhlodromus (Anthoseius) singularis and Typhlodromus (Typhlodromus) knisleyi, were also added.


Introduction
The family Phytoseiidae (Acari, Parasitiformes) being predatory, plays an important regulation role both in agricultural and natural ecosystems (McMurtry et al. 2013(McMurtry et al. , 2015Calvo et al. 2015;Lorenzon et al. 2018), and includes about 2,521 valid species (Demite et al. 2020). Many of them are considered important biocontrol agents of phytophagous mites and insects on crops, but despite more than a half century of intensive studies on this family and the great number of species described, only 20 species are presently reared in commercial insectaries (Knapp et al. 2018). It should be mentioned that this number has significantly grown in the last two decades with the increasing number of studies on bio-ethology, food preferences and ecology of less known or rare species (Quilici et al. 1997;Kreiter et al. 2002;Sznajder et al. 2011;Szabó et al. 2013;Tsolakis et al. 2016;Tsolakis and Ragusa 2017). The use of indigenous phytoseiid species, to control infestations of both endemic and invasive mite and insect pests, still represents the lower environmental impact strategy in agricultural ecosystems, and this should be the main scope of specialists in this field. It is commonly accepted that periodic surveys of phytoseiid mites on cultivated and spontaneous plants, are important to discover some rare species that could become future biocontrol agents of phytophagous mites on agricultural crops. As a matter of fact, it should be mentioned that the most common phytoseiids reared in insectaries world wide, i.e., Phytoseiulus persimilis Athias-Henriot, Neoseiulus cucumeris (Oudemans), Neoseiulus californicus (McGregor), Amblyseius swirskii Athias-Henriot, are rare species in natural ecosystems. Studies on phytoseiid mites in Italy, started in the 19th century by Canestrini and Fanzago (1876) and Berlese (1887Berlese ( , 1889, and continued by the latter author and Ribaga up to the first two decades of 20th century (Ribaga 1904;Berlese 1923). Afterwards, after a block of about 50 years, the studies on phytoseiid mites were resumed in a constant way starting from the 70s up to today (Ivancich-Gambaro 1975;Ragusa and Swirski 1976, 1982Ragusa 1979Ragusa , 1981Ragusa and Paoletti 1985;Duso and Sbrissa 1990;Tsolakis and Ragusa Di Chiara 1993;Ragusa Di Chiara and Tsolakis 1996;Tsolakis and Ragusa 1999;Tsolakis et al. , 2013Duso et al. 2004;Ragusa 2015, 2017;Lorenzon et al. 2018). At present, ninety-one valid phytoseiid species have been surveyed in Italy and 18 of them, were described as new species (Demite et al. 2020).
In the present paper we report nine new phytoseiid records from the Italian fauna, we describe a new species of Neoseiulus and redescribe two rare species, adding new information on them.

Materials and methods
Phytoseiid mites reported in the present paper were collected in different localities of Italy with the branch-shaking method (Tsolakis and Ragusa 1999). Specimens, fallen on a black plastic table, were collected using micro-aspirator and preserved in alcohol 70%. In laboratory they were cleared in Nesbitt solution and mounted on microscopic slides in Hoyer's medium. For the identification of the species and measurements, a differential interference contrast microscope (DIC) Zeiss Axioplan was used. Specimens of all species are kept in the Acari collection of the Laboratory of Agricultural and Applied Acarology "Eliahu Swirski", Department of Agricultural, Food and Forest Sciences, University of Palermo (Italy). All measurements are given in micrometres (μm), reporting mean (min-max) and were made using the Axiovision 40V 4.6.1.0 application (Zeiss, 2002(Zeiss, -2007. In the description of the new species, and the redescriptions we followed the nomenclature proposed by Lindquist & Evans (1965) as adapted to the Phytoseiidae by Rowell et al. (1978) for the dorsal and Chant and Yoshida-Shaul (1991) for the ventral chaetotaxy. For the terminology of various sections of the insemination apparatus (spermathecal apparatus), we followed Beard (2001), with some additions and changes. For setal patterns of leg IV podomeres (genu, tibia, tarsus), the formulae proposed by Evans and Till (1979) were adopted. For the macrosetae, we considered the concept defined by Beard (2001). Nomenclature of the adenotaxy was the one suggested by Athias-Henriot (1975). The following descriptive terms were here adopted after Athias-Henriot (1977): Habitus = a cluster of characters that determine the appearance of a structure, i.e., the shape of the dorsal shield, its reticulation (strong, slight, absent), the position of the setae, the shape of some setae, and isotrichy or anisotrichy; Hoplochorous = situated on a shield; Tylochorous = situated on a microsclerite, a small platelet on interscutal membrane; Gymnochorous = situated on the interscutal membrane; Holoadeny = presence of all dorsal solenostomes reported up to now for the Phytoseiidae family; Meriadeny = absence of one or more solenostomes; Receptaculum = the proximal segment of the major duct after the opening between the 3rd and the 4th pair of coxae, it may be simple or differentiate, in the latter case it is defined receptaculum; Embolus = the dimple present in the atrium on which the minor duct is inserted. The identification of the host plants was based on Pignatti (1982) and on the direct contribution of different botanists of the University of Palermo. For some species, we referred to various recent papers on Sicilian flora (Gianguzzi and La Mantia 2009;Musarella et al. 2018).

Results
All the phytoseiid species of the present work belong to our Acari collection. Various slides were labelled with the generic name followed by sp. (i.e., Neoseiulus spp.). Reorganising the collection, we classified them in their correct taxon status and we described the new species reported below.

Diagnosis of female
Dorsal shield slightly reticulated with a restriction at level of setae R1. Dorsal and peritrematal shields are fused at level of setae j1. All dorsal setae are slender and smooth except setae Z5 which are slightly serrated and the longest. Adenotaxy complete; solenostome gd3 well visible on peritrematal shield. Peritreme reaches the bases of setae j1. Sternal shield smooth with three pairs of setae (ST1-ST3) and two pairs of poroids (iv1 and iv2). Setae ST4 and poroids iv3 tylochorous. Genital shield with longitudinal striae; sigilla 1st-3rd pairs well visible. Sigilla of 4th and 5th pair well visible on the interscutal membrane between setae ZV1; sigilla of 6th pair posteroparaxial to setae ZV1. Ventrianal shield mostly reticulated with three pairs of preanal setae and a pair of small crateriform solenostomes (gv3). Setae JV5 smooth. Calyx of the insemination apparatus cup-shaped, without basal neck. Atrium nodular; minor duct well visible. Major duct cylindrical and narrow. Fixed digit of chelicera with seven teeth, movable digit with two teeth. Nine setae on genu II; three smooth and pointed macrosetae are present on leg IV, being of that on basitarsus the longest one.

Female
The description is based on 16 females.
( Figure 1 A-F) Dorsum ( Figure 1A) -Dorsal shield oval, waisted at level of setae R1, mostly reticulate. Seven pairs of small crescentic solenostomes are visible on the dorsal shield: gd1 posteroantiaxial to setae j3, gd2 posteroantiaxial to setae j4, gd4 posteroantiaxial to setae s4, gd5 posteroparaxial to setae z5, gd6 anteroparaxial to Z1, gd8 anteroantiaxial or anterior to Z4 and gd9 anteroparaxial to S5. Some poroids are visible on the dorsal shield. Some sigilla (muscle marks) are visible on the shield ( Figure 1A). The dorsal setae s4, S2, Z4 almost of the same length. Setae Z5 is the longest one. Same length have also the dorsocentral setae j1, j4 and j6. Setae r3 and R1 on the interscutal membrane. All setae are slender and smooth, except for Z5, thicker and slightly serrated. Measurements of dorsal and sublateral setae are as follows: mean (min-max) (mean of setae of the holotype are given in square brackets after the measurements of other specimens): j1 21 ( Peritreme ( Figure 1A) -Apex of peritreme reaches the bases of setae j1; 195 (183-202) [193] long. Solenostome gd3 sometimes visible on peritrematal shield at level of setae z4. Solenostome gdp crescentic, posterior to the opening of the stigma ( Figure 1A).

Etymology
The name "mediterraneus" refers to the Mediterranean countries where the type materials were found.

Remarks
Various slides with specimens of the new species were kept in the above mentioned Acari collection and labelled as Amblyseius sp. near umbraticus. Putting in order the collection and after the discovery of some specimens from Greece, we decided to describe the new species, considering the characters that differentiate it from the other nearer species.
Neoseiulus mediterraneus belongs to the cucumeris species group as defined by Chant and McMurtry (2003). Although it has been demonstrated that the above mentioned group is polyphyletic (Tsolakis et al. 2012), we adopted this taxonomy because no reorganization of this group has been proposed yet. Among the species included in the cucumeris species group, the new species resembles two other palearctic species, Neoseiulus umbraticus and N. pseudoumbraticus. Chant and Yoshida-Shaul (1982) described the latter species from specimens collected in Algeria, distinguishing it from N. umbraticus for some discrete characters: a different chaetotactic formula of genu II, presence/absence of pilus dentilis, different lengths of peritreme and number of macrosetae on leg IV (see Table 1). Neoseiulus mediterraneus shows the ancestral chaetotactic formula of genu II (2-2/1-2/1-1) among the above mentioned species, as well as for the whole cucumeris species group. Other ancestral characters are the distance between solenostomes gv3, greater in N. mediterraneus, the length of peritreme, longer in the new species, and a shorter macroseta on basitarsus IV.
Remarks -The species has been reported up to now only for Moldova (Wainstein 1973) and Iran (Faraji et al. 2007). The latter authors redescribed the species from one female collected on Citrus leaves. They reported some discordances with the original description regardings the lengths of various dorsal setae and the presence of a tooth on the movable digit that Wainstein (1973) considered edentate. In both our specimens a tooth is present on the movable digit, but in one of them it is vestigial. Wainstein described the species from only one specimen and probably he did not notice it or it was actually absent in the holotype. In the original description more than three teeth were reported on fixed digit, while Faraji et al. (2007) reported three teeth. On both our specimens we found four teeth (three between pilus dentilis and apical tooth and one beyond pilus dentilis). Waintein (1973) reported "seven pairs of small and large pores" on dorsal shield, while (Faraji et al. 2007) reported ten small visible pores. Evidently, the latter authors did not distinguish between solenostomes and poroids. In our specimens we verified the presence of seven small, but crataeriform solenostomes (gd1, gd2, gd4, gd5, gd6, gd8, gd9). Our measurements fit well with Waintein's original description, except for the setae j1 and z2, but also with Faraji's and co-authors' redescription (see Table 2). Proprioseiopsis dacus is reported in Italy for the first time. Typhloseiulus subsimplex (Arutunjan, 1972) Seiulus subsimplex Arutunjan (1972)  Remarks -The species have been reported up to now only for Armenia. This is the first record from Italy.
Remarks -As the previous species, Typhlodromus (A.) jordanis has been reported up to now only from Israel (Rivnay and Swirski 1980). We found this species on Tamarix spp. at the island of Pantelleria, but we never found it in Sicily. No information is available on the bio-ecology of this species.
Insemination apparatus ( Figure 2E) -Major duct short (4 long) and membranous. Receptaculum not visible. Atrium differentiated, slightly larger in comparison to the major duct (Ø 2), inserted at the basis of the calyx. A prominent ring enfolds the embolus; minor duct rarely visible. Calyx campanulate, membranous at the basis for about 1/3 of its length, thick walled afterwards, 13 long, 11 wide at the distal part and 9 at the mean distance. The membranous vesicle is commonly visible.
Chelicerae ( Figure 2D) -Fixed cheliceral digit 25 (24-25) long, with four teeth plus the apical one; three anteriorly and one posteriorly to pilus dentilis. Movable digit with one tooth plus the apical one, 27 long.

Remarks
In the original description (Chant 1957) the author reported only measurements of dorsal and ventral shields, presence of a tooth on the movable digit and of three teeth on the fixed one and no macrosetae on leg IV. Afterwards, Schuster and Pritchard (1963) redescribed the species from a single specimen from California, reporting some measurements and a clear drawing of the insemination apparatus. The above authors noted longer anterolateral setae in their specimen, a 34 long macroseta on basitarsus IV and a short and thick peritreme (reaching the level of setae z4). About a decade after, Chant et al. (1974) redescribed the species, adding measurements of some dorsal setae and giving information of some other discrete characters: chaeotaxic formulae of genua II and III, presence of a short macroseta on basitarsus IV, of three pairs of solenostome on dorsal shield (from the description we individuated them as gd2, gd6 and gd9), giving a schematic drawing of the insemination apparatus and reporting the presence of solenostome gv3 (Table 3). The above authors reported also a significant variation on peritreme's length and lengths of macrosetae on basitarsus IV, among specimens collected in various Canadian regions. They noted that in specimens with a short peritreme (apex reached at level of setae z4), an indistinguishable macroseta on basitarsus IV is present, while in specimens with a longer peritreme (apex at level of setae j3) there was a conspicuous macroseta on basitarsus IV, but they did not report any measurements of it. Chant et al. (1974) also noted that this species was collected also in the United States, but no remarks on Schuster and Pritchard redescription are mentioned. Congdon (2002) measured a specimen found on Tsuga heterophylla (Raf.) Sarg. (Pinaceae) in western Washington, reporting that this specimen matches the redescription given by Chant et al. (1974) in most characters, but it is intermediate between the specimen described by Schuster and Pritchard (1963) and Chant et al. (1974) as far as lengths of various dorsal setae are concerned (Table 3). Similarly, our specimens are intermediate between specimens reported in the latter two references and well match the specimen measured by Congdon (2002), except for the peritreme's length (Table 3). The species was, up to now, reported only from the Nearctic region (Canada and USA). This is the first record from the Palearctic region. For its distribution see Demite et al. (2020).

Female
The redescription is based on the holotype with additions based on four specimens. (Figure 3 A-E) Dorsum ( Figure 3A) -Dorsal shield almost oblong, rounded at the anterior and posterior levels, slightly waisted at level of setae R1 and weakly ornamented almost all over. Four pairs of crescentic solenostomes are visible on the dorsal shield: gd2 posteroantiaxial to setae j4 and posteroparaxial to setae z3, gd6 posteroparaxial to s6, gd8 anteroantiaxial or anterior to Z4 and gd9 anteroantiaxial to Z5. No poroids are visible on the dorsal shield and only sigilla saXIII and saXIV are visible on the shield (Figure 12). The dorsal setae j1 and j3 of the same length (23); the remaining dorsocentral setae, except J5, almost of the same length (14-17) ( Table 3). Similar lengths have the series z setae (15)(16)(17)(18)(19), while the anterolateral series s4 and s6 are quite longer (22 and 25 respectively). The longest setae on the dorsal shield are Z5 (57). Setae r3 and R1 on the interscutal membrane, of equal length (21). All setae are slender and smooth. Measurements of dorsal and sublateral setae of Sicilian specimen are as follows (in parentheses our measurements of the holotype and in brackets measurements reported in the original description): j1 21 (23)   Peritreme ( Figure 3A) -Apex of peritreme reaches anteriorly setae z2 (between setae j3 and z2). Solenostome gd3 not visible on peritrematal shield. Solenostome gdp crescentic, posterior to the opening of the stigma. Peritreme 139 (140) long.
Ventral idiosoma ( Figure 3B) -Sternal shield smooth with margins not well visible. Setae ST1 and ST2 inserted on the shield. Setae ST3 and ST4 tylochorous. Poroids iv1 and probably iv2 hoplochorus, the posterior margin of the shield is not well visible, but in our specimen iv2 is hoplochorus; poroids iv3 tylochorous. Length of sternal shield is not reported because of the bad position in the holotype. In our specimen distances between setae ST1-ST1, ST2-ST2 and ST1-ST2 are respectively 48, 57 and 30. Epigynial shield smooth, with a straight posterior margin. Genital sigilla not visible. Length between setae ST5, 55. Poroids iv4 on the interscutal membrane near the basis of the shield. Genital sigilla of 4th and 5th pair not visible in the holotype. Sigilla of 6th pair (sgpa) on the interscutal membrane, posteroparaxial to setae ZV1. The right ZV1 on a protrusion of the ventrianal shield. Ventrianal shield (VAS) almost triangular or sub-pentagonal, slightly waisted at level of setae JV2, and slightly reticulated; four pairs of setae (JV1-JV3 and ZV2), besides circumanal setae are present on VAS. Absence of the solenostomes gv3. The VAS of the holotype shows a lack of sclerotisation anteriorly to setae ZV2 in the left part of the scutum and a protrusion in the right part which included the seta ZV1. Length of VAS 106 (113), widths: at level of ZV2 97 (95) Insemination apparatus ( Figure 3E) -Major duct short and slightly sclerotised, 6 long and 3 wide. Receptaculum of the same width of the major duct. Atrium differentiated, slightly larger in comparison to the major duct (Ø 4); a light incidence distinguishes it from the calyx. A prominent ring enfolds the embolus; minor duct thin, poorly visible. Calyx campanulate, membranous at the base, thick walled afterwards, 16 long, 15 wide at the distal part and 11 at the mean distance. The membranous vesicle is always visible.
Chelicerae ( Figure 3D) -Fixed cheliceral digit 25 long, with four teeth plus the apical tooth; three anteriorly and one posteriorly to pilus dentilis. Movable digit with one tooth plus the apical one, 29 long.
Legs ( Figure 3C) -Ten setae are present on genu of leg I. Seven setae are present on genua of the remaining legs. Three smooth and pointed macrosetae are present on leg IV; on Sge and Sti macrosetae are pointed, on basitarsus slightly knobbed: Sge IV 24 (22)

Remarks
Typhlodromus (Typhlodromus) knisleyi was kept for a long time in the Acari collection of our laboratory and labelled as Typhlodromus sp. After its description from material collected at New Jersey (USA), only one specimen of T. knisley was reported from the Fraktò virgin forest (Greece) (Tsolakis and Ragusa 2009). This is the first record from Italy. It is certainly, a rare species mainly associated with forest plants. We have had the type material of T. (T.) knisleyi in loan by Harold Denmark and here we redescribe the species adding some characters not reported in the original description. Our measurements of the holotype are almost the same as those reported in the original description except for the setae j3 (27 in the original description and 23 measured by us) and the number of teeth on the fixid digit (two reported in the original description, but four, plus the apical one, in the present work: three anteriorly to pilus dentilis and one posteriorly).

Typhlodromus (Typhlodromus) kykladiticus Papadoulis & Emmanouel 1993
Typhlodromus kykladiticus Papadoulis & Emmanouel (1993)  Remarks -As above, also this species was collected in Sicily about a decade before its first description and kept in the Acari colection of our laboratory, labelled as Typhlodromus sp. The species has been reported up to now only from Greece.