Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 52. (Budapest 1960)

Berinkey, L.: Further morphological and osteological investigations on the hybrids of Hungarian Cyprinids

These are the following : the elevation of the body is 35,1 and 24,3% in the parents, therefore the hybrids are, in this regard, wholly bleak-like (24%) ; the breadth of the head is 13,6 and 10,0%, the offsprings show here a transitional 11,2% value ; the height of the head is 19,0 and 14,8%, and the hybrids again are transitional with their 16,0% value ; the predorsal distance is 59,9 and 55,6% that of the hybrids 54%, a dominating bleak feature ; the preventral distance is 49,2 and 44,7 %, the hybrids, with their 50,6%, agree with the rudd ; the preanal distance is 71,6 and 63,5%, the hybrids are wholly of a rudd character (70,2%) ; the V.—A. distance is 24,5 and 20,2%, the 23,3% of the hybrids show the dominancy of the rudd ; the height of the caudal peduncle is 10,6 and 8,46%, the hybrids are again transitional with their 9,04% ; the D. length is 12,8 and 10,0%, that of the hybrids 9,53%, a bleak character again ; the D. height is 19,2 and 16,6%. the hybrids are again bleak-like (15,8%) ; the A. length is 14,6 and 19,8%, with 12,3% in the hybrids, a rudd dominancy ; the interorbital distance is 40,5 and 30,9%, the 31,2% value of the hybrids agree completely with that of the bleak. The average values of the morphological characters reveal it therefore that the hybrids show 5 corresponding characters with those of the bleak, and 4 with the rudd, while 3 of their features are transitional between the parental species. Beside the morphological characters, I have also compared the skeletons of the parent-species and the hybrids. I examined several skeletons of the parental species, but only one of the hybrids, as I had only two species. I wish to discuss those bones only which are rather different in the parent-species, allowing the establishment of a sure conformity with one of them in the case of the hybrids. The pharyngeal teeth formula of the bleak is 2,5—5,2, rarely 2,5—4,2, or 2,5—5,3 ; that of the rudd is 3,5—5,3. I examined this bone in both hybrids and found that they were completely agreeing, the number of the pharyngeal teeth being 2,5—5,2. B e n e c k e (3) found, in his 8 specimens, 2,5—5,2 in three hybrids, 2,5—5,3 in four, and 3,5—5,3 in one, while Vutskits (19) observed 2,5—5,2 in both specimens examined by him. In the hybrids, also the shape of the pharyngeal teeth conforms with that of the bleak : they are weakly serrated and slightly hooked. Concerning the form of the pharyngeal arches, the greatest difference between the two species is that this bone of the rudd is squatter and thicker than that of the bleak, the upper branch of the pharyngeal arch being shorter, its shoulder broader. This bone of the hybrids resembles in shape that of the bleak, with only its slighter thickness revealing a rudd effect. Thus, though the bleak effect is stronger, we have to classify this as having a transitional character due to the showing of some rudd features too. The number of vertebrae of the hybrid is 44, identical with that of the bleak. The shape of the vomer (fig. 1—3)* of the bleak is narrow, elongated, its two anterior processes include an acute angle, its posterior part tapers evenly to a point. In the rudd, this bone is short and broad, its anterior processes including a right angle, its posterior part straight, narrowing out suddenly, broken in an angle. The vomer of the hybrid agrees wholly with that of the rudd. The frontale is comparatively narrow and long in the bleak, short and broad in the rudd : the hybrid is, in this regard, of a bleak character, though there is a slight effect of the other parent too. The biggest breadth in the length of the frontale of the bleak is 52,2%, that of the rudd 66,8%, and 57% in the hybrid. * The figures were drawn by my colleague, L. Esztergályos.