Octodrilus mimus

Octodrilus mimus (Rosa, 1889)

(Figure 4 C,D)

Allolobophora mima RosA, 1889 BoLL. MUs. TorIno, 4 (60): 1.

Octolasium mima f. marenzelleri MIchAELsEn, 1910 Ann. MUs. ST.-PETErsb., 15: 1.

Octolasium mima f. marenzelleri: OModEo 1954 ATTI MUs. CIv. ST. NAT. TrIEsTE, 19: 131.

Octolasium (Octodrilus) mima: OModEo 1956 Arch. ZooL. ITAL., 41: 177 (pArT).

Octolasium mima TypIcUM: OModEo 1962 MEM. MUs. CIv. ST. NAT. VEronA, 10: 79.

Octolasium mima marenzelleri: OModEo 1962 MEM. MUs. CIv. ST. NAT. VEronA, 10: 80.

Octolasium mima mima: KArAMAn 1972 BIoL. VEsTn. 20: 102 (pArT. EXcL. vAr. tergestina MIchAELsEn, 1910, vAr. rucneri PLIsko & ZIcsI, 1970, vAr. nov. slovenica).

Octodrilus mima: ZIcsI 1981 OpUsc. ZooL. (BUdApEsT), 27–28: 166.

Octodrilus mima: ZIcsI 1986 OpUsc. ZooL. (BUdApEsT), 22: 108.

Octodrilus marenzelleri: ZIcsI 1986 OpUsc. ZooL. (BUdApEsT), 22: 108.

Octodrilus mimus: MršIć 1991 Monogr. EArThw. BALkAns: 411.

Material examined. Medea 2 (MH 032875), 4: Colle di Medea, Gorizia, Italy, 18/02/2016, leg. Maurizio G. Paoletti. Velika 1 (EWITA271-15): Velika Gorica, Croatia, 04/09/2014, leg. Enzo Moretto. Velebit 2 (EWITA270- 15): Trnovac-Velebit, Croatia, 05/09/2014, leg. Angelo L. Dreon. Groinizza 1 (MH 032871), 2 (MH 032872): Groinizza, Gorizia, Italy, 23/11/2016, leg. Luca Dorigo. (Altogether six specimens).

Diagnosis. Medium to large sized worms, 120–400 mm by 10–15 mm. Colour brown on dorsum with darker midsegment stripes and pale on ventrum. Male pores on 15 small. Clitellum on 1/n 28, 28–40, 41; tubercles on 1/n 28, 29–40, 41. 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 six to seven pairs, in 6/7–11/12, 12/13.

Remarks. The taxonomy of Oc. mimus is quite controversial. The different varieties and forms described (tergestina, marenzelleri, vallorum, slovenicus) have later been treated differently. Omodeo (1954) regarded both marenzelleri and vallorum as forms of Octolasium mima, but later marenzelleri was treated as a subspecies (Omodeo 1962). Karaman (1972) regarded vallorum as a subspecies of mima, marenzelleri as a synonym and tergestina, rucneri and the newly described slovenica as forms. Zicsi (1982) elevated all forms, varieties and subspecies to species rank. Mršić (1991) thoroughly analyzed the literature data and his own large collection and concluded that marenzelleri is a synonym of Oc. mimus, while Oc. tergestinus, Oc. rucneri, Oc. vallorus and Oc. slovenicus represent independent species.

Our molecular analysis confirmed the distinctness of Oc. slovenicus, which forms a distinct, highly supported clade together with the Oc. pseudocomplanatus specimens. Oc. mimus is sister to a clade composed of Oc. complanatus and Oc. zicsiniello sp. nov. and seemingly not closely related to Oc. tergestinus. The Oc. mimus clade consists of specimens with typical mimus characters (cl. 28–40, spermathecae 6/7–11/12) and also with marenzelleri characters (cl. 29–41, spermathecae 6/7–12/13) therefore their synonymy is maintained.