Diplodontus semiperforatus (Walter, 1925)

Pešić, Vladimir, Bańkowska, Aleksandra, Saboori, Alireza, Mabrouki, Youness, Taybi, Abdelkhaleq Fouzi & Zawal, Andrzej, 2023, First record of the halobiontic Diplodontus semiperforatus (Acari, Hydrachnidia) from North Khorasan, with notes on water mites from saline habitats of Iran, Persian Journal of Acarology 12 (4), pp. 533-541 : 535-537

Diplodontus semiperforatus (Walter, 1925) ( Figs. 1A, B, E )

Material examined

Iran, IR14-2022 North Khorasan Province, Qareh Ghan , a remnant pool of river crossing Feshanjerd-Gurpan-Esfarayen road, 36.9358° N, 57.2071° E, 2 Aug. 2022, leg. Pešić 1♀ (sequenced, BOLD /GenBank HYDIR036-23 /OR501657; Table 1), ♀ dissected (one palp and chelicera slide mounted, idiosoma conserved in Koenike fluid); environmental characteristics of the sampling site: pH 7.79, water temperature 24 °C, conductivity 36.4 mS/cm, dissolved oxygen 15.97 mg /L .

Molecular data

A 658-bp fragment was successfully amplified ( BOLD accession code: HYDIR 036-23). The specimen shows a 11.5 % of divergence (uncorrected p -distance) to specimens of D. s capularis from Morocco, as well an 15.5% of divergence to specimens of D. haliki from Australia.

Remarks

The specimen from Iran molecularly analyzed in this study matches the description of D.

semiperforatus. From its sister species D. scapularis , the female of D. semiperforatus can be distinguished by the shape of the chelicerae (claw relatively longer, length ratio basal segment/claw ˂ 1.7) (compare Figs. 1B and C ).

Habitat

The only site in northeastern Iran where D. semiperforatus was collected was a remnant pool of a saline river ( Fig. 2 ) (conductivity 36.4 mS/cm). In shore areas of this river, the formation of salt crusts was noticeable. Bank vegetation was represented by a Phragmites belt, while the submerged vegetation consisted of Chara sp. , which formed uniform mats over much of the bottom area. The soil mainly consisted of fine sediments, in which anaerobic conditions prevail.

Accompanied species

The single specimen of D. semiperforatus was collected together with a larger number of Hydrachna specimens that morphologically matched the description of H. skorikowi (Piersig, 1900) , a species considered to be widespread in the Palaearctic. This species, which inhabits all kinds of standing and slow running waters, has been reported as tolerant against high salinity and can be found in water bodies with conductivity up to 8700 μS/cm ( Gerecke 1991). Genetic data indicate that a single successfully barcoded specimen of H. skorikowi from northeastern Iran forms a unique cluster ( BOLD: AFF6278) with the closest neighboring BIN is that of H. skorikowi ( BOLD: ACS0797) which includes specimens from the Netherlands and Morocco. The high p -distance (11.11%) between these two BINs indicates the need for taxonomic revision of the H. skorikowi complex, indicating the presence of possibly undescribed cryptic species.

Distribution Algeria, Morocco, Tunisia, Southern France (?), Italy (Sicily).

Figures

Figure 1. A-B, E: Diplodontus semiperforatus (Walter, 1925), ♀, Qareh Ghan, Iran – A. Palp, lateral view; B. Chelicera; E. Photograph of genital field. C–D: Diplodontus scapularis Dugès, 1834, Messoussate, Morocco (C – ♀, F – ♂) – C. Chelicera; D. Photograph of genital field. F. Maximum Likelihood tree (GTR+I model) of the genus Diplodontus obtained from 6 nucleotide COI sequences.

Figure 2. Photograph of sampling site (Qareh Ghan, North Khorasan Province) of Diplodontus semiperforatus in northeastern Iran. Photo by V. Pešić.