Barbronia borealis Bolotov, Eliseeva & Kondakov, 2023

Bolotov, Ivan N., Eliseeva, Tatyana A., Kondakov, Alexander V., Gofarov, Mikhail Y., Aksenova, Olga V., Bespalaya, Yulia V., Kropotin, Alexander V., Travina, Oksana V. & Vinarski, Maxim V., 2023, Barbronia borealis sp. nov., the first salifid leech discovered in Russia, with a global checklist of this genus, Ecologica Montenegrina 63, pp. 24-38 : 28-30

Barbronia borealis Bolotov, Eliseeva & Kondakov sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:06EF7905-A09C-4F37-B686-36A0D67A7F7D

Figures 4 , 5 a-c

Holotype: RMBH Hir_0405 (fixed and stored in 96% ethanol); RUSSIA: Kiparisovka River , 43.4578°N, 131.9017°E, Razdolnaya (Suifun) River basin, Primorye Region, September 05, 2020, O. V. Aksenova, Y. V. Bespalaya, A. V. Kropotin, O. V. Travina & M. V. Vinarski leg.

Etymology: The name of this species reflects its record in the boreal zone of Eurasia.

Differential diagnosis: The new species is externally similar to Barbronia gwalagwalensis and B. weberi . It differs from B. gwalagwalensis by having 5.5 annuli between gonopores (vs 7.5 annuli) and from B. weberi by having 6 annuli between accessory pore and corresponding gonopore (vs 5 annuli). However, DNA barcoding should be considered the most reliable approach for identification of these morphologically similar species.

DNA-based diagnosis: The reference DNA sequences of the holotype: OQ940656 (COI) and OQ941865 (18S rRNA). This species represents a divergent phylogenetic lineage, which is distant from other species in the genus, the sequences of which are available ( Table 2 ).

Description: Small salifid leech: body length 20.1 mm, maximum body width 3.3 mm, maximum width of anterior sucker 0.9 mm, maximum width of posterior sucker 2.0 mm ( Figure 4 ). Body elongated, vermiform, tapering anteriorly. Body surface smooth, without papillae. Posterior sucker ventrally directed. Dorsum light ochraceous, venter whitish. Anterior region with three pairs of circular eyespots: one labial on 3rd annulus and two buccal on 6-7th annuli ( Figure 5 a-b). Complete mid-body somite 6 annulate: b1 + b2 + a2 + b5 + c11 + c12 ( Figure 5c ). Clitellum extends from X b5 to XIV b2. Gonopores large, well visible, separated by 5.5 annuli. Male accessory pore in the furrow X c12/XI b1, male gonopore in XII b1/b2, female gonopore in XIII b1, female accessory pore in XIII c12/XIV b1 ( Figure 5c ). Anus dorsally at XXVII, two postanal annuli anterior to posterior sucker ( Figure 4 ). Reproductive and digestive systems remain unstudied because only the holotype was available for description.

Distribution: This species is only known from its type locality, situated at the southeastern corner of the Russian Far East. However, numerous occurrences from Northeastern China attributed to B. cf. weberi ( Figure 1 ) may belong to the new species.

Habitats and ecology: The holotype was collected from a pool site of a small river with clay bottom ( Figure 6 ). This leech specimen was fixed with its prey, an oligochaete, protruding from its mouth. A COI sequence was generated from this worm (GenBank acc. No. OQ933549). Searching with the BOLD IDS reveals that the COI sequence of the prey item is related to those of oligochaetes identified as Limnodrilus profundicola (Verrill, 1871) (Oligochaeta: Naididae ). This finding indicates that Barbronia borealis sp. nov. feeds on small freshwater oligochaetes, as do some other species in this genus ( Nesemann et al. 2007).

Figures

Figure 1. The northernmost occurrences of the Salifidae in their native range in East Asia. The red star indicates the type locality of Barbronia borealis sp. nov. in Primorye Region, Russia. The yellow circles indicate records of Barbronia cf. weberi in Northeastern China (Moore 1930; Yang 1996). The blue circle indicates records of Barbronia gwalagwalensis and B. sp. ‘Korea’ in South Korea (Kwak et al. 2021). Georeferenced occurrence dataset is presented in Appendix 2 (numbers of localities on the map correspond to those in the appendix).

Figure 4. Dorsal (D) and ventral (V) views of the holotype of Barbronia borealis sp. nov. (RMBH Hir_0405). Abbreviations: PI, prey item (an oligochaete specimen); AS, anterior sucker; PS, posterior sucker; map, male accessory pore; fap, female accessory pore; mg, male gonopore; fg, female gonopore; an, anus. Scale bar = 1.0 mm. Photos: Tatyana A. Eliseeva.

Figure 5. External morphological features of the holotype of Barbronia borealis sp. nov. (RMBH Hir_0405). (a-b) Arrangement of three pairs of eyespots: dorsal view (a) and lateral view from right side (b). (c) Ventral region of clitellum, with male (mg) and female (fg) gonopores, and male and female accessory copulatory pores (map and fap, respectively). Body somites are indicated by roman numerals; symbols b1, b2, a2, b5, c11, and c12 indicate the number of annulus. Scale bars = 0.5 mm (a-b) and 1.0 mm (c). Photos: Tatyana A. Eliseeva; graphics: Ivan N. Bolotov.

Figure 6. Type locality of Barbronia borealis sp. nov.: Kiparisovka River, 43.4578°N, 131.9017°E, Razdolnaya (Suifun) River basin, Primorye Region, Russia, September 05, 2020. Photo: Olga V. Aksenova.