Torrenticola ( Torrenticola ) galaica Pešić, 2025

Pešić, Vladimir, Girão, Dinis, Vergata, Chiara, Da Silva, Luís P. & Ferreira, Sónia, 2025, A new species of Torrenticola ungeri complex (Acari, Hydrachnidia, Torrenticolidae), and new water mite records for Portugal, Zootaxa 5717 (1), pp. 1-17 : 8-12

Torrenticola ( Torrenticola) galaica Pešić sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:

Figs. 2, 3A–B

Material examined: Holotype ♀, Portugal, Viana do Castelo, Monção, Podame , near bridge, 42.0351°N, 8.3839°W, 40 m asl, 19 Aug. 2024, leg. Ferreira, Girão & da Silva, dissected and slide mounted (DNA barcoded; voucher Id: BGE _00580_F08; RMNH) . Paratypes: 2♀ (DNA barcoded; BGE _00580_H05, BGE _00580_H06), Viana do Castelo, Arcos de Valdevez, Breia, Sieiros picnic park, 41.8967°N, 8.4388°W, 53 m asl., 19 Aug. 2024, leg. Ferreira, Girão & da Silva.

Diagnosis (Males unknown): Morphological: Characters of the Torrenticola ungeri species group (shoulder platelets fused or partially fused with dorsal plate, Cxgl-4 posterior to Cxgl-2); dorsal shield with colour pattern as illustrated in Fig. 3A–B; the angle of the dorsal plate between the frontal plates slightly pointed, with the anterior part of the dorsal plate lying relatively wide between the traces of the shoulder plate delimitation; tip of Cx-I with several long setae; excretory pore slightly posterior to Vgl-2; ventral margin of P-3 without serration, ventral margin of P-4 with fine serration. Molecular: This lineage corresponds to a unique Barcode Index Number (BIN) BOLD: AGP6165, which differs from the T. ungeri ungeri clade (BOLD:AED2307) by 8.60% K2P divergence in the COI gene.

Description. Female. Idiosoma oval (dorsal shield L/W ratio 1.2); shoulder platelets fused with dorsal plate ( Fig. 2A); dorsal shield with colour pattern as illustrated in Figs. 3A–B; gnathosomal bay U-shaped, proximally rounded; tip of Cx-I with long setae; Cxgl-4 posterior to Cxgl-2; medial suture line of Cx-II+III relatively short; posterior suture lines of Cx-IV extending posteriorly beyond posterior margin of genital field, laterally curved; genital field pentagonal in shape; excretory pore and Vgl-2 away from the line of primary sclerotization, excretory pore slightly posterior to Vgl-2; gnathosoma ventral margin curved, rostrum well developed; P-2 ventral margin slightly curved, ventrodistal protrusion slender; ventral margin of P-4 with fine serration and 3–4 ventral tubercles, bearing one longer, and three shorter setae (Figs. D–E).

Measurements— Idiosoma (ventral view: Figure 2B) L 956, W 788; dorsal shield ( Figure 2A) L 806, W 658, L/W ratio 1.23; dorsal plate L 763; frontal plate L 193–200, W 64, L/W ratio 3.0–3.1. Gnathosomal bay L 177, Cx-I total L 354, Cx-I mL 178, Cx-II+III mL 38; ratio Cx-I L/Cx-II+III mL 9.3; Cx-I mL/Cx-II+III mL 4.7. Genital field L/W 198/193, ratio 1.03; distance genital field-excretory pore 222, genital field-caudal idiosoma margin 343.

Gnathosoma vL 453; chelicera L 522; palp total L 444, dL/H: P-1, 56/45; P-2, 152/70; P-3, 86/68; P-4, 125/45; P-5, 23/18; L ratio P-2/P-4, 1.22. dL of I-L-4–6: 130, 144, 128; I-L-6 H 40; dL/H I-L-6 ratio 3.2.

Male. Unknown.

Etymology: The species name galaica refers to the presence of this species on the northwest Iberian Peninsula from which the new species is currently only known.

Species delimitation using DNA barcodes: The final alignment for species delimitation using COI sequence data comprised 669 nucleotide positions (nps) from 130 Torrenticola specimens (representing ten Torrenticola spp. characterized by dorsal shield with two free anterior platelets and shoulder platelets partially fused with large dorsal plate) listed in Table 2. Monatractides madritensis (K. Viets, 1930) from Serbia was used as outgroup. The Neighbour-Joining (NJ) tree is presented in Figure 4. COI sequences obtained from Torrenticola specimens collected in Portugal, here described as T. galaica sp. nov., forms a strongly supported clade (BIN BOLD:AGP6165). In the phylogenetic tree, this clade appeared as a sister group to the cluster containing sequences of Torrenticola ungeri from the Balkans. The mean K2P genetic distance between the BIN of the new species and its closest neighbour, BOLD:AED2307 (which includes sequences of T. ungeri ungeri ), was estimated at 8.60%. The mean intraspecific K2P distance within the new species cluster was 0.2%.

Discussion: The new species belongs to the Torrenticola ungeri species complex, which currently includes two species known from the Palaearctic region: T. ungeri and T. neoungeri . The Portuguese species differs from both species in having a more rounded idiosoma (dorsal shield L/W ratio 1.2) and a distinct dorsal shield color pattern (compare Fig. 3A–B with Figs. 3C–E).

Additionally, the new species differs in the shape and configuration of the dorsal plate: the angle between the frontal plates is only slightly pointed, and the anterior part of the dorsal plate lying between the traces of the shoulder plate delimitation is relatively wide. In contrast, both T. neoungeri and T. ungeri exhibit a more sharply pointed angle between the frontal plates, a narrower anterior section of the dorsal plate between the traces of the shoulder plates, and more strongly pronounced angles of the shoulder plate traces posterior to setae Dgl-3.

Distribution: Portugal; known from the two streams ( Fig. 5) in northwestern part of the country.