Octodrilus istrianus Mršić, 1991

Octodrilus istrianus MršIć 1991 Monogr. EArThw. BALkAns: 406.

Octodrilus istrianus: HAckEnbErgEr & HAckEnbErgEr 2013 ZooTAXA, 3710: 19.

Material examined. Brioni 2 (EWITA196-15): Brijuni Island, Croatia, 30/11/2014, leg. Enzo Moretto . Torrente V1 (MH 032883), V3 (MH 032884), V4 (MH 032885), V5, V6: Zlepcari, Pican, Croatia, 15/05/2016, leg. Maurizio G. Paoletti & Enzo Moretto. (Altogether six specimens).

Diagnosis. Large sized worms, 250–300 mm by 10–15 mm. Colour grey on dorsum and paler on ventrum. Male pore on 15 small. Clitellum on 1/n 29, 29–42, 1/n 43; tubercles on 29, 30–42, 1/n 43. Nephridiopores irregularly alternate between b and above d. Two pairs of testes enclosed in perioesophageal testis sacs in 10, 11. Vesicles in 9–12, those in 11 sometimes smaller. Spermathecae seven pairs, in 6/7–12/13.

Remarks. Oc. istrianus has relatively recently been described and has not been reported after the original description until now. Our specimens, collected also on the Istria peninsula, completely agree with the original description. Morphologically, it stands in between Oc. mimus and Oc. tergestinus (cl. 28, 29–40 and 28, 29–44 respectively) however, on our molecular tree these specimens form an unresolved, well-supported subclade (0.96 PP) inside the tergestinus clade. The status of this species needs further clarification by analysing more material from or near the type locality and involving more genes.