On Hungarian Branchiobdellids (Oligochaeta: Branchiobdellidae)

By

M. A. SUBCHEV (Received August 23, 1983)

A B S T R A C T . A short descr ipt ion of three branchiobdel l id species f rom Hungary i s given. One of them, Branchiobdella pentodonta Whi tman , is new for the fauna of Hungary. A key for a l l Hungarian branchiobdel l ids is also provided.

Branchiobdel l ids are epibionts on crayfishes and, as an exception, on other freshwater crustaceans (HOLT, 1965). Because of th is unusual manner of l i fe they often escape the at­tention of special is ts on Oligochaeta.

A t f i r s t branchiobdel l ids were considered to belong to the order Hi rudinea , but l a te r the group was placed among the Oligochaeta (STEPHENSON, 1930). HOLT (1965), however, proposed to separate the branchiobdell ids into the order Branchiobdel l ida , which together w i t h the orders Oligochaeta, Hirudinea and Acanthobdellida are grouped in the class C l i t e l -la ta , so the systematic status of the group is s t i l l debatable.

A l l European branchiobdel l ids (and a some of the As ian ones) belong to subfamily B r a n -chiobdell inae. Th i s subfamily di f fers f rom the Cambarinconcolinae (al l A m e r i c a n species and some of the As ian ones) in having only a single pa i r of testes in the V body segment ( H O L T , 1973). Af t e r the revis ion of POP (1965) and the w o r k s of K A R A M A N (1970), K O Z A -ROV, M I C H A I L O V A et SUBCHEV (1972) and SUBCHEV (1978), 7 species are conf i rmed to occur in Europe; Branchiobdel la astaci Odier , 1823; B. parasita Henle, 1835; B . pentodon-ta W h i t m a n , 1882; B . hexodonta Gruber , 1883; B . i t a l ica Canegallo, 1928; B . balcanica Moszynsk i , 1937 and B . kozarovi Subchev, 1978. In addition to this a new subspecies has been described f rom Jugoslavia by K A R A M A N (1970) - B . balcanica sketi Karaman , 1970.

F E R E N C Z (197 9) noted only two species of the fami ly Branchiobdell idae for the fauna of Hungary in her "Guide for the ident i f ica t ion of aquatic Oligochaeta of Hungary". In the p r e ­sent w o r k a short descr ip t ion of three other species f rom Hungary is given: for two of them on the basis of l i t e r a tu r e data, and for one - on the basis of ma te r i a l examined by the author. A key to a l l 5 Hungarian species of branchiobdel l ids is also given.

Branchiobdel la hexodonta. The body of the l ive w o r m s i s almost c y l i n d r i c a l ; when fixed the body i s s l ight ly widened in 5th to 7th t runk segments. Only in this European species a groove divides the head into two par t s . Upper and lower jaws are s i m i l a r w i t h long l a t e ra l teeth and three or four shorter and median teeth equal in size. B . hexodonta i s a g i l l - inhab i t ­ing species. It i s known for Hungary f r o m m a t e r i a l collected in Újbánya, the host i s not men­tioned (POP, 1965).

Branchiobdel la balcanica balcanica. The body of the l ive w o r m s is sp ind le - formed; when fixed i t i s do r so -ven t ra l ly flattened. The most charac ter is t ic feature that separates th is species f rom the other representat ives of the so-cal led "pentodonta group" ( K A R A M A N , 1970) i s that the 4th t runk segment is d i s t inc t ly wider than the 3rd one. Upper and lower jaws are s i m i l a r , w i t h 5 o r 6 teeth ( ra re ly 4 o r 7) - l a t e r a l teeth and median tooth longer than the other ones. The usual local izat ion on the c rayf i sh i s the an te r io r par t of the body including

F i g . 1: Branchiobdella paras i ta , jaw F i g s . 2-3: B . astaci (2= upper jaw. 3= lower jaw) F igs . 4-7: B. pentodonta (4= jaw; 5= general view of body; 6= spermatheca; 7= male r e p r o ­

ductive system) F i g s . 8-10: B . balcanica (8= general view of body; 9= spermatheca; 10= male reproduct ive

system) (Abbreviat ions: a= a t r i u m (glandular pa r t ) , b= bursa, d . j ac .= ductus ejaculator ius

(nonglandular par t of a t r i u m ) , p= penis)

chelae. Th i s subspecies, descr ibed as B . pentodonta o r i e n t á l i s POP, 1965, is known for Hungary f rom m a t e r i a l collected in Újbánya , the host is not mentioned (POP, 1965). L a t e r th is subspecies was synonymized to B . balcanica balcanica by K A R A M A N (1970).

Branchiobdel la pentodonta. 27 specimens of th i s species were collected on Astacus as- tacus L . f rom the Bükk National P a r k , Csernely-patak (a smal l b rook) , Hungary; they i n ­clude 11 mature and 16 unmature w o r m s . The branchiobdel l ids were fixed in 80% a lcohol and than examined by means of a stereoscope; two of the mature w o r m s were dissected and the reproduct ive system and the jaws were removed fo r more detailed invest igat ions. The mate ­r i a l was ident if ied as B . pentodonta by the form of the body and the f o r m of the jaws and the reproductive system. No differences f rom the o r i g i n a l descr ipt ion of the species and f r o m Bulgar ian m a t e r i a l were found. The body of the f ixed mature w o r m s is dorso-ven t ra l ly f l a t ­tened, but the extension f rom the 3 rd to the 6th t runk segment i s gradual , unlike in the p r e ­vious species; the jaws are s i m i l a r to the jaws of B . balcanica balcanica. In addition to th is there i s a cer ta in d is t inc t ion between the reproduct ive systems of B . pentodonta and B . ba l ­ canica respect ive ly . In B . pentodonta the glandular pa r t of the a t r i u m is d is t inc t ly longer than the nonglandular one (ductus ejaculatorius) whi le the situation i s vice versa in B . balca­ nica balcanica; in B . pentodonta the duct of the spermatheca is shor te r than i ts length and w e l l defined, and in B. balcanica balcanica the duct i s re la t ive ly longer and no d i s t inc t d iv id ­ing l ine between the theca and the ductus is v i s ib le as is the case in B . pentodonta.

F o r a l l Hungarian species except B. pentodonta and B. balcanica the form of the jaws i s a re l iab le feature fo r ident i f ica t ion . In addition to this the f ixed m a t e r i a l of the species could be divided in two groups (which is useful for p r e l i m i n a r y ident i f ica t ion) : big b r a n c h i ­obdell ids (mature w o r m s usually longer than 5 mm) - B . astaci and B . parasita and medium-sized branchiobdel l ids (mature w o r m s usually shor te r than 5 mm) - B . hexodonta, B . pento­ donta and B. balcanica.

KEY T O T H E HUNGARIAN SPECIES OF T H E GENUS BRANCHIOBDELLA

1. Jaws t r i angu la r 2 Jaws not t r i angu la r , w i t h 5 or 6 teeth , 3

2. Jaws equal in size B . paras i ta Dor sa l jaw more than twice l a r g e r than ven t ra l one B . astaci

3. Jaws w i th long l a t e r a l and equal in size 3 or 4 med ia l teeth B . hexodonta Jaws w i th l a t e r a l and media l teeth l a rger than others 4

4. Body widening gradually f rom 3rd to 6th t runk segment, glandular par t of the a t r i u m d i s ­t inc t ly longer than nonglandular B . pentodonta 4th t runk segment in mature w o r m s dis t inc t ly w i d e r than 3 rd ; glandular part of a t r i u m d is t inc t ly shor ter than nonglandular B. balcanica

The s ix th European branchiobdel l id species - B . i t a l ica is not expected to be found in Hungary since i t s only host Austropotamobius i t a l i c u s , does not inhabit this country. So far the remain ing species, B. koza rov i , is known only f rom Bulgar ia and the Ukraine (BOSHKO, 1983).

ACKNOWLEDGEMENTS are due to D r . L . F O R R Ó , for the m a t e r i a l of B. pentodonta.

REFERENCES

BOSHKO, E.(1S83): Oligochaeta, inhabi t ing on crayf ishes f rom Ukrainian waters . Report I . Branchiobdel l idae (in Russian). Vestnik zoo log i i , 2: 13-19.

F E R E N C Z , M . (1979): A guide for the ident i f icat ion of aquatic Oligochaeta of Hungary. In : F e l f ö l d i , L . ( ed i t . ) . Hydrobiology for water management p rax i s (in Hungarian). - V I Z -DOK, Budapest, 7: 1-170.

H O L T , P . (1965): The systematic posi t ion of the Branchiobdell idae (Annelida: C l i t e l l a t a ) . -Syst. Z o o l . , 14 (1): 25-32.

H O L T , P. (1973): A summary of the Branchiobdel l id (Annelida: Cl i te l la ta ) fauna of Mesoame-r i c a . - Smithsonian Contr . Z o o l . , 142: 1-40.

K A R A M A N , S. (1970): Be i t r ag 2ur Kenntnis der e u r o p ä i s c h e n Branchiobdel l iden (C l i t e l l a t a , Branchobdelloidea). - Int . Rev. ges. H y d r o b i o l . , 55 (3): 325-333.

KOZAROV, G . , M I C H A I L O V A , P . & SUBCHEV, M . (1972): Studies on Branchiobdell idae (Oligochaeta, Annelida) in B u l g a r i a . - Annua i re de l ' U n i v e r s i t é de Sofia, 64 (1): 77-89. (in Bulgar ian) .

POP, V . (1965): Systematische Revis ion der europaischen Branchiobdell idae (Oligochaeta). -Zool . Jb. Syst . , 92 (2-3): 219-238.

STEPHENSON, 1. (1930): Oligochaeta. - Oxford, pp. 978. SUBCHEV, M . (1978): A new branchiobdel l id - Branchiobdel la kozarovi sp. n . (Oligochaeta,

Branchiobdell idae) f rom Bu lga r i a . - Acta zool . bulg . , 9: 78-80.

A u t h o r ' s address: D r . Mi tko A . SUBCHEV Insti tute of Zoology Bulgar ian Academy of Sciences 1000 Sofia, bu l . Ruski 1 BULGARIA