Dr. Éva Murai szerk.: Miscellanea Zoologica Hungarica 2. 1984 (Budapest, 1984)

Subchev, A. M.: On Hungarian Branchiobdellids (Oligochaeta: Branchiobdellidae)

On Hungarian Branchiobdellids (Oligochaeta: Branchiobdellidae) By M. A. SUBCHEV (Received August 23, 1983) ABSTRACT. A short description of three branchiobdellid species from Hungary is given. One of them, Branchiobdella pentodonta Whitman, is new for the fauna of Hungary. A key for all Hungarian branchiobdellids is also provided. Branchiobdellids are epibionts on crayfishes and, as an exception, on other freshwater crustaceans (HOLT, 1965). Because of this unusual manner of life they often escape the attention of specialists on Oligochaeta. At first branchiobdellids were considered to belong to the order Hirudinea, but later the group was placed among the Oligochaeta (STEPHENSON, 1930). HOLT (1965), however, proposed to separate the branchiobdellids into the order Branchiobdellida, which together with the orders Oligochaeta, Hirudinea and Acanthobdellida are grouped in the class Clitellata, so the systematic status of the group is still debatable. All European branchiobdellids (and a some of the Asian ones) belong to subfamily Branchiobdellinae. This subfamily differs from the Cambarinconcolinae (all American species and some of the Asian ones) in having only a single pair of testes in the V body segment (HOLT, 1973). After the revision of POP (1965) and the works of KARAMAN (1970), KOZAROV, MICHAILOVA et SUBCHEV (1972) and SUBCHEV (1978), 7 species are confirmed to occur in Europe; Branchiobdella astaci Odier, 1823; B. parasita Henle, 1835; B. pentodonta Whitman, 1882; B. hexodonta Gruber, 1883; B. italica Canegallo, 1928; B. balcanica Moszynski, 1937 and B. kozarovi Subchev, 1978. In addition to this a new subspecies has been described from Jugoslavia by KARAMAN (1970) - B. balcanica sketi Karaman, 1970. FERENCZ (197 9) noted only two species of the family Branchiobdellidae for the fauna of Hungary in her "Guide for the identification of aquatic Oligochaeta of Hungary". In the present work a short description of three other species from Hungary is given: for two of them on the basis of literature data, and for one - on the basis of material examined by the author. A key to all 5 Hungarian species of branchiobdellids is also given. Branchiobdella hexodonta. The body of the live worms is almost cylindrical; when fixed the body is slightly widened in 5th to 7th trunk segments. Only in this European species a groove divides the head into two parts. Upper and lower jaws are similar with long lateral teeth and three or four shorter and median teeth equal in size. B. hexodonta is a gill-inhabiting species. It is known for Hungary from material collected in Újbánya, the host is not mentioned (POP, 1965). Branchiobdella balcanica balcanica. The body of the live worms is spindle-formed; when fixed it is dorso-ventrally flattened. The most characteristic feature that separates this species from the other representatives of the so-called "pentodonta group" (KARAMAN, 1970) is that the 4th trunk segment is distinctly wider than the 3rd one. Upper and lower jaws are similar, with 5 or 6 teeth (rarely 4 or 7) - lateral teeth and median tooth longer than the other ones. The usual localization on the crayfish is the anterior part of the body including