Hygrobates calabricus, Pešić & Goldschmidt, 2022

Pešić, Vladimir & Goldschmidt, Tom, 2022, Hygrobates calabricus, a new species of water mite (Acariformes, Hydrachnidia, Hygrobatidae) from Italy, based on morphological and molecular evidence, Ecologica Montenegrina 50, pp. 59-66 : 63-65

Hygrobates calabricus sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:916B3A71-6C13-4F05-A9CA-438122B48E5E

Fig. 2

Material examined — Holotype ♂ ( RMNH), sequenced [ BOLD Acc No.: DCBDJ073-21 ; voucher code: CCDB 38392 G01], dissected and slide mounted, Italy, Calabria, Sila, Giganti de la Sila , stream, pool, 39.3184 N, 16.4596 E, 1405 m asl., 22 Aug. 2018, leg. Goldschmidt. Paratype: 1♂, same data as holotype .

Diagnosis (Male) — Anterior margin of male genital field with a less pronounced medial projection, posterior margin without indentation, with a small convexly rounded projection; L of IV-L-6 proximoventral seta 38 μm.

Description: Male — Colour yellowish. Integument finely striated. Posteromedial margin of Cx-I rounded, caudo-lateral apodemes of Cx-I+II slightly developed ( Fig. 2A ); Cx-IV subtriangular, with a distinct noselike protruding medial margin. Anterior margin of genital field convex, with a small medial projection, typically with irregular margin of a secondary sclerotization, posterior margin due to the secondary sclerotization without indentation, with a small centrally rounded projection, Ac in triangular arrangement ( Fig. 2B ). Gnathosoma anteriorly with clearly offset projections. P-2 ventral margin straight, distally forming a right angle, denticles covering distal half of ventral margin; P-3 with denticles covering distal two thirds of ventral margin; P-4 ventral setae on the same level ( Figs. 2 C-D).

Measurements — Idiosoma L 1080; coxal field: L 516; Cx-III W 677; mL of Cx-I + gnathosoma L 392; distance between lateralmost ends of caudo-lateral Cx-II apodemes, 194; genital field L/W 247/288, ratio 0.86; L Ac 1-3: 75-81, 72-78, 84-91.

Chelicera total L 402, L basal segment 266, claw 141, L basal segment/claw ratio 1.9. Palp: total L 588; dL/H, dL/H ratio: P-1, 67/31, 2.1; P-2, 151/89, 1.69; P-3, 113/77, 1.47; P-4, 189/46, 4.1 (basal H 41, dL/basal H ratio 4.7); P-5, 68/27, 2.6; P-2/P-4 ratio 0.6.

Legs: dL of I-L-1-6: 84, 115, 159, 219, 241, 234. dL of IV-L-1-6: 160, 177, 272, 378, 381, 344; L of IV-L-6 proximoventral seta 38, L of IV-L-6 medioventral seta 15.

Female — Unknown.

Etymology — Named after the (so far eclusive) occurrence of the species in Calabria ( Italy).

Remarks — The phylogenetic analysis based on COI data placed Hygrobates calabricus sp. nov. as a sister clade to H. setosus , a species with a preference for running water habitats as well. The average K2P genetic distance between these two species was estimated to be 8.7±1.2% K2P indicating their genetic isolation. The results of ASAP analysis strongly supported the species status of the Hygrobates specimens collected in Calabria.

Morphologically, the male of H. calabricus sp. nov. differs from H. setosus in the posterior margin of the genital field without indentation (posterior margin indented in H. setosus ) and a longer proximoventral seta on IV-L-6 (30 µm in H. setosus ). From H. limnocrenicus (in parentheses) the new species differs in a narrower genital field (L/W ratio 0.8), smaller acetabula (Ac-3>110 μm) and posterior margin of the genital field without indentation (vs. indented in H. limnocrenicus ).

Distribution: Italy (so far only known from one stream in South Italy (Calabria, Fig. 3 ).

Figures

Figure 2. Hygrobates calabricus sp. nov., holotype ♂, Giganti de la Sila, Italy: A – gnathosoma, coxal and genital field; B – genital field; C – palp, medial view (P-1 lacking); D – palp, lateral view (P-1 lacking); E – chelicera; F – IV- L-5 and -6 (inset: proximo and –medioventral setae of IV-L-6). Scale bars = 100 µm.

Figure 3. Sample site of Hygrobates calabricus sp. nov. in Calabria (South Italy).