O. G. Dely szerk.: Vertebrata Hungarica 21. (Budapest, 1982)
Daravskii, I. S. ; Kupriyanova, L. A.: Rare males in parthenogenetic lizard Lacerta armeniaca Méhely 69-76. o.
whether L. armeniac a shows any interpopular variation in these chromosomes, although such facts have been known for sex chromosomes of other species of lizards (WRIGHT 1973). An analogical heteromorphic (the 18th) pair of chromosomes was also observed in the karyotypes of females of several species of the family Lacertidae: L. triliniat a, Eremias ollvier i, E. arguta, E. velox, L. strigat a, Ophisops elegán s and was absent in male karyotypes of the 4 latter species studied (GORMAN 1969, IVANOV & FEDOROVA 1970, IVANOV 1973, BHATNAGAR & YONISS 1976). The authors assumed that these chromosomes were sex chromosomes, and that sex determination in these species was of the ZW(g)/ZZ (à) type. We suppose that the heteromorphic pair of chromosomes in females of L. armeniac a are also sex chromosomes inherited from the ancestral species. The W-chromosome seems to contain the genes determining female sex and is involved in actively determining femaleness. This fact almost certainly implies that mating of diploid parthenogenetic females of L. armeniac a with bisexual species of the genus Lacert a always produces only triploid females. The only exception is the triploid hybrid male L. rostombekov i x L . raddei , though it should be noticed that the animal had oviducts in addition to well-developed testes. The karyotypical identity of diploid females, the male and the intersex of L. armeniaca indicates the nonhybrid nature of the two latter Individuals which was supported by our earlier assumption that a cause of the appearance of diploid male individuals in L. armeniaca , presumably with ZW chromosomes, lies probably in their hormonal sex reversion. Karyological study of the somatic cells of the newly captured male L. armeniac a confirmed its diploid nature, too (2n = 38). Unfortunately, only a few dividing cells at metaphase with well-spread chromosomes were at our disposal, which may perhaps be explained by the time of fixation, late in autumn. This prevented us from studying the morphology of the chromosomes in greater detail to identify the heteromorphic pair in the karyotype. The diploid nature of the male is supported by cytophotometric investigations of the DNA contents in their blood cell nuclei. The DNA quantity in somatic cells of this male and in the control diploid male of L. portschinskl l (2 n = 38) is practically the same, while this value in the hybrid female L. dahl i x L. portschinskl l is almost 1.5 times higher, which corresponds tb the triploid level (Table 1). Special attention was paid to the study of spermatogenesis in the male of L. armeniaca. Meiosis is well known to be a critical moment for an animal as its normal course provides the production of normal gametes. As it was expected for the autumn fixation, we have not observed many dividing cells at metaphase I and H in both of the males examined, but both of them displayed a haploid set of bivalents (h = 19, Plate I.: Figs 5-6). The bivalents were cross- and ring-shaped and had only terminal associations. The two smallest bivalents showed no features characteristic of sex bivalents (heterocyclicity, "end-to-end" conjugation) and did not differ from each other; they formed a symmetrical ring-shaped figure and were not associated with other bivalents. The success of unisexual species depends in many respects on the capability of females to reproduce mature eggs with a somatic chromosome complement. One of the mechanisms contributing to this end is the blocking of cytokinesis in one of the mitoses prior to melosls, which leads to doubling the chromosome number. This has been demonstrated for gynogenetic fishes, amphibians and unisexual lizards of the genus Cnemidophoru s (MACGREGOR & UZZELL 1964, CUELLAR 1971, CIMINO 1972). The same mechanism is presumably operating in parthenogenetic lizards of the genus Lacert a (UZZELL 1970). At the same time, the haploid number of bivalents at metaphase I of the diploid male of L. armeniac a shows that the blocking of cytokinesis is lacking in it. Whether this mechanism is operating during meiosis of some tri- and tetraploid hybrid males and females of the genus Cnemidophoru s that have been studied remains unknown (LOWE et al. 1970, NEAVES 1971, CUELLAR & McKINNEY 1976, COLE 1979). Whether the gametes will have balanced chromosome sets depends on the regularity of chromosome disjunction in meiosis. Therefore of special interest was the measurement on mean DNA content of the spermatids on smear preparations of both the study and the control males. This value was found to be almost half as much as that in the nuclei of the blood cells of the same specimens, that is, conforming to their haploid level (Table 1). The great number of haploid spermatids in both of the males shows that in the course of meiosis the bivalents undergo the first and then the second division of maturation and then normally disjunct to the poles, forming haploid gametes. PLATE II. Figs 7-9: Histological section of testes: Lacerta portschinskii . general view, x 400 (7), L. armeniac a. general view, x 400 (8), L. armeniac a. presence of spermatozoa, x 630 (9)
