Dina serbica, Pešić & Grosser, 2022

Pešić, Vladimir & Grosser, Clemens, 2022, Dina serbica, a new species of leeches (Annelida: Hirudinea: Erpobdellidae) from Serbia, based on morphological and molecular evidence, Ecologica Montenegrina 51, pp. 1-14 : 7-10

Dina serbica sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:5863D4B2-FB65-40B4-A511-AAF022DCA97B

Fig. 3 , 4B

Material examined — Holotype ( SMF), sequenced (voucher code: CCDB 38362 H03), Serbia, Western Serbia, Kamena Gora, spring on the road to Kamena Gora, 43.32333 N, 19.57636 E, 21 July 2021, leg. Pešić, body length 40 mm, width 6.5 mm, caudal sucker 4.5 mm wide . Paratypes: three specimens (body length/width: 42/ 7 mm, 42/ 7 mm, 34/ 6 mm), same data as holotype , two specimens of them sequenced ( CCDB 38362 H01-H02; SMF) , one specimen ( CCDB 38362 H01) dissected .

Diagnosis — Dorsal surface with numerous yellowish spots. Genital pores separated by two annuli (the male gonopore in the furrow b2/a2, the female in the furrow b5/b6). Atrial cornua short. Ovisacs short extending to annulus a2 of the second somite behind the female genital pore, and curled in their entire course.

Description. Habitus — Medium sized leeches; preserved and contracted adults reach a body length of 42 mm (paratype). The body is slightly dorso-ventrally flattened. The caudal sucker is slightly narrower than the maximum body width. The mouth is wide; the upper lip of the oral sucker not elongated ( Fig. 3A ).

Annulation — Leeches with a typical Dina -like annulation. The midbody somites quinqueannulate with annulus b6 only slightly broadened, more clearly broadened in the last half of the body. Annulus b6 not or only very slightly subdivided into annuli c11 and c12, other annuli not subdivided. The male genital pore situated in the furrow b2/a2, the female in the furrow b5/b6. The genital pores separated by two annuli.

Eyes — The visible eyes reduced. The holotype and two studied paratypes possesses one eye each.

Colour — The colour of living specimens varies brownish to greenish. The dorsal surface of preserved specimens is bright greyish with two dark paramedian longitudinal stripes, along the entire length.

Each annulus bears a transverse row of bright and numerous yellowish spots ( Fig. 3C ). Papillae on the dorsal surface, corresponding with the yellowish spots, slightly visible.

Sexual organs — The atrial body small and rounded, cornua short and strong, reaching the border of the somite ahead (approximately to the furrow b6/b1), slightly curved ventrally, ends straight or very slightly curved ventrally, base of the cornua thickened and distinctly offset ( Figs. 3 E-D). The vas deferens with preatrial loop, strongly coiled and thickened from the third ganglia behind the female genital pore and extending to the next four ganglia; that begins the part with numerous testes ( Fig. 4B ).

The ovisacs are short and strongly curled in their entire course, extending to annulus a2 of the second somite behind the female genital pore ( Fig. 4B ).

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

Remarks — The phylogenetic analysis based on COI data placed Dina serbica sp. nov. as a sister clade to D. minuoculata Grosser, Moritz & Pešić, 2007 , a species originally described from a first-order stream in the Tara river canyon in North Montenegro ( Grosser et al. 2007). The average K2P genetic distance between sequences of the specimens of D. minuoculata collected from its locus typicus and D. serbica sp. nov. was estimated to be 11.96±1.49% K2P indicating their genetic isolation.

Morphologically, Dina serbica sp. nov. resembles D. minuoculata , in regard to the presence of bright yellowish spots on the dorsal surface of each annulus, the genital pores separated by two annuli and a short atrial cornua. From the latter species, Dina serbica sp. nov. can be separated in having a short and curled ovarian sacks (vs. not curled, and one somite longer in D. minuoculata , compare Figs. 4A and -B ). Moreover, the reduction of pigmentation of eyes is much further progressed in the new species.

Distribution — Serbia; so far only known from one spring in Western Serbia ( Fig. 5 ).

Habitat — The new species was collected in a rheopsammocrene (seeping rheocrene with sandy-gravel substratum) spring ( Fig. 6B ) in deciduous forest dominated by the common beech ( Fagus sylvatica L.).

Figures

Figure 3. Dina serbica sp. nov. A – mouth opening, paratype; B – lateral view, paratype; C – colour of the dorsal surface, holotype; E-D – genital atrium, ventral view, paratype.

Figure 4. Reproductive system. A – D. minuoculata Grosser, Moritz & Pešić, 2007, paratype, a first order stream in the Tara river canyon, Montenegro. B – Dina serbica sp. nov., paratype, spring along the road to Kamena Gora, Serbia. Abbreviations: a = genital atrium, b = vas deferens, c = ovarian sacks, d = testisacs.

Figure 5. Map of studied area with marked type localities of Dina serbica sp. nov. (1), D. minuoculata (2), D. montana (3) and D. prokletijaca (4). Inset: Live specimen and coccon of D. serbica sp. nov. from the type locality (Kamena Gora, Serbia).

Figure 6. Photographs of the type localities of selected Dina species. A – a first-order stream in the Tara river canyon, Montenegro (locus typicus of D. minuoculata). B – rheopsammocrene spring along the road to Kamena Gora, Serbia (locus typicus of D. serbica sp. nov.). C – rheocrene spring Toplla, Dečani, Kosovo* (locus typicus of D. prokletijaca). D – spring at Štavna, Komovi Mt., Montenegro (locus typicus of D. montana). Photos by V. Pešić (A, D), L. Pešić (B), V. Berlajolli (C).