Torrenticola eseni Pešić, Zawal & Smit, 2023

Pešić, Vladimir, Zawal, Andrzej, Saboori, Alireza, Bańkowska, Aleksandra, Cakmak, Ibrahim & Smit, Harry, 2023, New records of water mites (Acari, Hydrachnidia) from Iran and Türkiye based on morphology and DNA barcodes with description of one new species, Ecologica Montenegrina 66, pp. 11-29 : 18-25

Torrenticola eseni Pešić, Zawal & Smit sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:7FA63156-6458-4EEF-9511-E75E7EA80B55

Figs. 2- 3 , 4E

Material examined — Holotype ♂, sequenced ( HYDIR018-23 ), dissected and slide mounted ( RMNH), TÜRKIYE, Aydin Province, TR6-2023 Aydin, stream near Şirindere , 37.9297° N, 27.7775° E, 14.iii.2023, leg. Pešić. Paratypes: 1♂, 2♀, same data as the holotype , 1♂, 1♀ sequenced ( HYDIR011-23 , HYDIR012- 23 ) ( RMNH) ; 1♀, TÜRKIYE, Aydin Province, TR12-2023 Tabakhane stream near Kalfaköy , 37.8744° N, 27.8459° E, 18.iii.2023, leg. Pešić, sequenced ( HYDIR022-23 ) , dissected and slide mounted ( RMNH).

Diagnosis — Dorsal shield with a colour pattern as photographed in Fig. 4E ; in male the medial suture of Cx-II+III long (120 μm); ejaculatory complex with proximal horns and well-developed anterior keel, L 177 μm.

Description — General features — Idiosoma oval-elongated (dorsal shield L/W ratio 1.3-1.4); shoulder plates separated from dorsal plate, dorsal shield with a colour pattern as photographed in Fig. 4E ; area of primary sclerotization of the dorsal plate with two dorsoglandularia; gnathosomal bay U-shaped; Cxgl–4 subapical; excretory pore located on the line of primary sclerotization ( Fig. 2B ); gnathosoma with a curved ventral margin ( Fig. 2E ); P-2 and P-3 with a narrow ventrodistal projection, P-4 with a well-developed ventral tubercle, bearing one longer and three shorter setae ( Figs. 2D , 3B ). Male — Medial suture line of Cx-II+III relatively long; genital field subrectangular; ejaculatory complex conventional in shape (with proximal horns and well-developed anterior keel; Figs. 2 F-G). Female — Genital field pentagonal in shape.

Measurements. Male (Holotype) — Idiosoma L 681, W 459; dorsal shield L 556, W 388, L/W ratio 1.44; dorsal plate L 525; shoulder plate L 178-181, W 55-56, L/W ratio 3.22-3.26; frontal plate L 119, W 47-50, L/W ratio 2.4-2.5; shoulder/frontal plate L 1.5-1.53. Gnathosomal bay L 138, Cx-I total L 283, Cx-I mL 144, Cx-II+III mL 122; ratio Cx-I L/Cx-II+III mL 2.3; Cx-I mL/Cx-II+III mL 1.18. Genital field L/W 122/94, ratio 1.3; distance genital field-excretory pore 116, genital field-caudal idiosoma margin 153. Ejaculatory complex L 177. Gnathosoma vL 259, chelicera L 309; palp total 285, dL/H, dL/H ratio: P-1, 36/30, 1.2; P-2, 86/50, 1.72; P-3, 54/45, 1.21; P-4, 89/31, 2.85; P-5, 20/14, 1.45; L ratio P-2/P-4 0.97. dL of I-L: 34, 67, 81, 94, 106, 105; I-L-6 H 46; dL/H I-L-6 ratio 2.29.

Ecologica Montenegrina , 66, 2023, 11-29

Female (paratype from Tabakhane stream near Kalfaköy) — Idiosoma L 931, W 650; dorsal shield L 753, W 548, L/W ratio 1.37; dorsal plate L 709; shoulder plate L 219, W 81-84, L/W ratio 2.6-2.7; frontal plate L 150-159, W 69-72, L/W ratio 2.1-2.3; shoulder/frontal plate L 1.38-1.46. Gnathosomal bay L 190, Cx-I total L 359, Cx-I mL 169, Cx-II+III mL 28; ratio Cx-I L/Cx-II+III mL 12.8; Cx-I mL/Cx-II+III mL 6.0. Genital field L/W 178/178, ratio 1.0; distance genital field-excretory pore 231, genital field-caudal idiosoma margin 337. Egg maximum diameter (n =1) 300. Gnathosoma vL 338, chelicera L 391; palp total 352, dL/H, dL/H ratio: P-1, 39/39, 1.0; P-2, 116/66, 1.76; P-3, 66/56, 1.17; P-4, 108/34, 3.1; P-5, 23/16, 1.46; L ratio P-2/P-4 1.07. dL of I-L: 66, 81, 97, 114, 123, 114; I-L-6 H 42; dL/H I-L-6 ratio 2.7.

Etymology — The new species is named after Prof. Yunus Esen (Bingöl ¸ Türkiye) in appreciation of his comprehensive work on Turkish water mites.

Discussion — The new species from Türkiye belongs to the Torrenticola laskai- species group. Males of the latter species, which has often been confused with T. barsica (complex), are distinguished by a relatively long medial suture line of Cx-II+III and the genital field with its maximum in the anterior third ( Di Sabatino et al. 2010). Torrenticola laskai , was originally described by Láska (1955) but misattributed to T. lativalvata K. Viets, 1952 , a species known from Algeria, probably belonging to the T. barsica- complex ( Di Sabatino et al. 2009). Later on, Di Sabatino et al. (2009) described European populations of T. cf. lativalvata as a new species, T. laskai Di Sabatino, 2009 , with the type locality in Corsica. Recently the status of T. laskai has been questioned by Pešić & Smit (2022), who, based on molecular data, revealed that the latter species might be a complex of cryptic species. They barcoded specimens of T. laskai from Corsica, and showed the presence of two highly supported clades (TL-Gp1 and TL-Gp2 sensu Pešić & Smit 2022) with a COI divergence estimated at 11.04 ± 1.46% K2P ( Pešić & Smit 2022). Considering the similarity in size and shape of the ejaculatory complex, the latter authors assumed that the T. laskai Gp 2-Clade corresponds with the nominal species. From the latter species, the new species from Türkiye differs in a different colour pattern of the dorsal shield (compare figs. 4A vs. 4E) and a comparatively smaller ejaculatory complex (177 vs. 220 µm in T. laskai ).

The second Corsican clade ( T. laskai -Gp1 sensu Pešić & Smit 2022), clusters within BOLD:AEN8967, which, in addition to specimens from Corsica, includes two specimens from Asturias in Spain (identified as Torrenticola sp. , deposited in Taxus Medio Ambiente, Spain). Morphologically, the specimens of the latter clade can be separated from the T. laskai -Gp2 Clade and the new species from Türkiye by the shape of the ejaculatory complex (larger, L 288 μm, proximal chamber comparatively more enlarged, see Fig. 3f in Pešić & Smit 2022), indicating that it is probably an undescribed species.

Phylogenetic analysis of the COI data of populations of the Torrenticola laskai complex reveals the presence of four well supported clades. In our COI tree, the sequences of specimens from Türkiye form a highly supported clade which is placed (albeit with a low support) as a sister species of T. laskai- Gp2 clade from Corsica and Sardinia ( Fig. 5A ). The genetic distance (10.66% K2P; Table 3) between these two clades indicates a long independent history of these species. The genetic distances between T. eseni sp. nov. and the European clades were higher than the barcoding gap found by the ASAP method (5% to 7% - Figs. 5 B-C), which supports the species-status of the new species.

The results of the applied ASAP procedure that grouped the COI sequences of T. laskai from SE Europe together with a sequence of T. dowlingi Pešić, 2020 from Iran, agrees with results of Pešić & Smit (2022) who suggested that populations from SE Europe should be attributed to T. dowlingi . From the new species from Türkiye, T. dowlingi can be separated by a different colour pattern of the dorsal shield (as illustrated in Figs. 4 C-D).

Distribution — Türkiye.

Figures

Figure 2. Torrenticola eseni sp. nov., holotype ♂ [CCDB_39399_B06], stream near Şirindere, Türkiye. A – dorsal shield; B – ventral shield; C – I-Leg-5 and -6; D – palp, lateral view (P-1 lacking); D – gnathosoma and chelicera; F-G – ejaculatory complex. Scale bars = 100 μm.

Figure 3. Torrenticola eseni sp. nov., paratype ♀ [CCDB_39399_B10], Tabakhane stream near Kalfaköy, Türkiye. A – dorsal shield; B – palp, medial view (P-1 lacking). Scale bars = 100 μm.

Figure 4. Photographs of dorsal shields. A – Torrenticola laskai ♂ [CCDB 38559 G11], stream N of Col de Bavella, Corsica. B – T. laskai ♂ [CCDB 38559 F01], Riviere Casaluna, Corsica. C – T. dowlingi paratype ♂, river near Karaj, Iran. D – T. laskai, ♂, Crnovrška River, Serbia. E – T. eseni sp. nov., paratype ♀, stream near Şirindere. Photos by V. Pešić. Figs. A-B (from Pešić & Smit 2022; in Pešić & Smit 2020 fig. 3, the photographs of dorsal shield and ejaculatory complex for specimens [CCDB 38559 G11] and [CCDB 38559 F01] respectively, were mistakenly replaced, thus fig. 3c-d refers to [CCDB 38559 G11] and fig. 3f-g to [CCDB 38559 F01]), C-D (from Pešić et al. 2020b).

Figure 5. A Maximum Likelihood tree (GTR+G+I model) of the genus Torrenticola obtained from 33 nucleotide COI sequences. The results of species delimitation by ASAP procedure are indicated by vertical bars. B-C Results of ASAP analysis for COI sequences of the selected species of the genus Torrenticola. B – Distribution of pairwise differences; C – Ranked pairwise differences.