Podapolipoides chorthippus n. sp. (Acari: Prostigmata: Podapolipidae), an ectoparasite of Chorthippus sp. (Orthoptera: Acrididae) from southern Iran

The ectoparasitic mite Podapolipoides chorthippus Majidi and Hajiqanbar n. sp. (Acari: Prostigmata: Podapolipidae), is described and illustrated from Fars province, southern Iran. Colonies of mites were recovered from pronotum and near hindwing bases of acridid grasshoppers, Chorthippus sp. (Orthoptera: Acrididae: Gomphocerinae). This is the first parasitism record of the genus Podapolipoides on grasshoppers of the genus Chorthippus.


Introduction
Symbiotic relationships, including parasitism, with arthropods have been frequently evolved among different groups of mites. One of the most sophisticated ones is Prostigmata (Acari: Acariformes) which is comprised of species that occupy various habitats (Walter et al. 2009). Some species of this lineage are phoretic or parasitic on insects, mostly classified in Parasitengona and Heterostigmata cohorts, yet some other families like Cheyletidae and Dytiscacaridae have evolved parasitism (Walter et al. 2009; Mortazavi et al. 2018. Within Heterostigmata, the family Podapolipidae Ewing, 1922 with 32 genera and more than 290 described species, is one of the largest families in Prostigmata (Majidi et al. 2019). Members of this family are highly specialized obligate parasites of insects of five orders namely, Coleoptera, Orthoptera, Blattodea, Heteroptera and Hymenoptera (Husband & OConnor 2014; Seeman 2021.

Materials and Methods
Collected grasshoppers were preserved in vials with 96% ethanol. Subsequently, grasshoppers and alcohol sediments from the vials were examined for parasitic mites. Host grasshoppers were collected from Latifi region, located in Fars province, Southern Iran in 2017. Colonies of mites were separated from pronotum and near wing bases of acridid grasshoppers, Chorthippus sp. (Orthoptera: Acrididae: Gomphocerinae) ( Figure 1). Mite specimens were cleared in Nesbitt's solution and mounted in Hoyer's medium. Morphology of the mites was studied using a compound microscope (Olympus BX51, Tokyo, Japan) equipped with phase contrast illumination. Photographs were taken with the aid of Samsung i70 digital camera. All measurements in the descriptions are given in micrometers for the holotype and five paratypes (in parentheses). The terminology follows Lindquist (1986). Details of geographical position have been recorded using GPS mobile device. Setae with no longer than the diameters of setal acetabulae are considered as microsetae and those with only acetabulae and no setal remnants are assigned as vestigial setae. The host insect was identified with the help of Dr. Mustafa Ünal (Abant İzzet Baysal Üniversitesi, Turkey).
Idiosomal venter ( Figure 3B) -with apodemes I, II and presternal apodeme (appr) developed; apodemes II (ap2) not reaching to presternal apodeme; coxal fields I without setae 1a; coxal fields II with one pair of smooth and pointed setae 2a 6; coxal fields III fused and bearing only one pair of smooth and pointed setae 3b 16.

Differential diagnosis
The male of new species belongs to a cluster of species sharing setae c 2 100-125 µm long (see the following key for related these species): Podapolipoides faini Husband, 1995, P. locustanus Lavoipierre, 1941, P. alatus Husband, 1990, P. cochisensis Husband, 1993and P. anacridii Hajiqanbar and Joharchi, 2011. According to length of setae sc 2 (80-96), P . chorthippus (86) is similar to P. faini (80) and P. cochisensis (96) but differ from from P. cochisensis by the length of setae 3b 16 (vs vestigial in P. cochisensis) and P. faini in the length of cheliceral stylets 14 (vs 8 in P. faini) and coxal seta 3b shorter than gnathosomal width (vs equal to gnathosomal width in P. faini) also coxal seta 2a shorter than 1/3 gnathosomal width (vs about 1/3 gnathosomal width in P. faini), and in P. chorthippus larvae setae c 2 is longer than d (vs c 2 is subequal to d in P. faini). Regarding to setae 1a, P . chorthippus n. sp. with no setae 1a is similar to P. alatus but differs from it by setae sc 2 reaching to beyond bases of setae c 2 (vs not reaching to bases of setae c 2 in P. alatus). Based on apodemes II, P . chorthippus n. sp. resembles P. anacridii, P. faini and P. locustanus but differs from P. anacridii by ap1 reaching appr (vs not reaching appr in P. anacridii) and differs from P. locustanus by setae sc 2 reaching beyond bases of setae c 2 (vs not reaching beyond bases of setae c 2 in P. locustanus). Among the congeners found in neighboring countries, it is similar to P. jordani Husband, 1992. However, male of the new species differs from that of P. jordani by sc 2 reaching beyond bases of setae c 2 , ap2 not reaching appr, and length of tc″ 103 (vs sc 2 not reaching beyond bases of setae c 2 , ap2 reaching appr, tc″ 156 in P. jordani). The remainder of the comparative measurements is summarized in Table 1.
Based on length of setae v 1 and v 2 (v 1 > v 2 ), larval females of the P. chorthippus n. sp. can be easily distinguished from all other species of the genus except P. flechtmanni Husband, 1993. Based on longer setae v 2 than v 1 , and almost the same length of setae h 1 , sc 2 and f, larval females of P. chorthippus are similar to those of P. flechtmanni. However, they differ in shape of setae d, f, h 2 . In P. chorthippus, setae d are thin and pointed, f serrate, and h 2 slightly thickened (vs d, f, h 2 thick and minutely spine-like in P. flechtmanni); setae c 2 12-22 at least two times longer in P. chorthippus n. sp. (vs 6 in P. flechtmanni); and coxal setae I and II microsetae (vs 2 in P. flechtmanni).

Etymology
The new species is named based on the genus name of the grasshopper host (Chorthippus).