Panisus torrenticolus Piersig, 1898

Pešić, Vladimir & Goldschmidt, Tom, 2023, New DNA-assisted records of water mites from Sardinia, with the description of a new species (Acari, Hydrachnidia), Ecologica Montenegrina 69, pp. 24-44 : 32-33

Panisus torrenticolus Piersig, 1898 – group

Fig. 5 A-C

Material examined — ITALY, Sardinia, Comune di Fluminimaggiore, It 2022-1c, Sorgente Pubusinu , S of Fluminimaggiore, approx. 5km gravel road from the junction of the SS 126 to the E, strong karst spring, moss carpet on broken dam, 39.4099° N, 8.5275° E, 206 m asl., 7. Aug. 2021, leg. Goldschmidt 1♀ (sequenced; voucher ID: CCDB-44301-G06), dissected and slide mounted ( RMNH) .

Remarks — The single female from Sardinia, used in this study for molecular analysis, morphologically matches the description of Panisus torrenticolus . The latter species is diagnosed by a characteristic porosity of the muscle attachment sclerites, having a centre of fine pores surrounded by a circle of large pores and an outer area of finer pores ( Fig. 5A, B ). Further features include the frontal shield as long as wide, or longer than wide, and dorsolateral plates without or with only slightly projecting lateral extensions ( Fig. 5A ) ( Di Sabatino et al. 2010).

The sequenced specimen from Sardinia forms a unique BIN (BOLD:AFC5560) with the nearest neighbouring BIN BOLD:AET0970, which includes a specimen of P. chicamoi Valdecasas , García- Jiménez & Fernández- Campoamor, 2021(GBMNF37305-22) from Spain, a species recently described by Valdecasas et al. (2021) from Murcia, Spain. In our COI tree, the specimen from Sardinia appeared as sister clade of the latter species from Spain. The p -distance between these two BINs was estimated at 15.54% indicating a long independent history of these two clades.

In order to finally define the taxonomic status of the new lineage from Sardinia, the taxonomic situation of two other Western Mediterranean species needs to be clarified first :

Panisus clypeolatus Maglio, 1909 , originally described from Trentino-Alto Adige, Italy ( Maglio 1909) and later on reported from the Western Mediterranean (e.g., Algeria: K. Viets 1951, Bader 1989; France: Motas 1928a, b, Lundblad 1956; Italy: Cicolani & Di Sabatino 1985). It was synonymized with P. torrenticolus by Di Sabatino et al. (2009). The type material of P. clypeolatus is lost and the original description does not include original details that allow a definition of this taxon (see Di Sabatino et al. 2009 for discussion).

Panisus lundbladi Bader, 1981 , a species originally described from Spain based on a specimen collected by Lundblad in an aqueduct in Girona, Catalonia ( Bader 1981). Morphologically, the latter species is somehow intermediate between P. michaeli Koenike, 1896 and P. torrenticolus , resembling the latter species in the presence of a ring of larger pores on most muscle attachment sclerites, and to P. michaeli in the presence of an enlarged frontal shield and the extensive lateral ramifications of the dorsolateralia. For now, it seems most appropriate to leave the clade from Sardinia as “ Panisus torrenticolus – group” until more specimens from Western Mediterranean, including specimens from the loci typici of the two above mentioned species with uncertain taxonomic status become available.

Figures

Figure 5A-C. Panisus torrenticolus group, ♀ [CCDB_39399_B10], ITALY, Sardinia, Comune di Fluminimaggiore, Sorgente Pubusinu, It 2022-1c: A – photograph of dorsum; B – dorsocentralia; C – genital field. Scale bar = 100 μm.