Cytogenetic studies of Hynobiidae (Urodela). IX. Karyological characteristics ofHynobius abei Sato by means of R-and C-banding

Summary Chromosomal characteristics of the salamander speciesHynobius abei, from Ohimya (Kyoto) were revealed by the techniques of R-and C-banding. The karyotype ofH. abei was characterized by the shortness of an R-negative (C-positive) band in the terminal region of the long arm of chromosome 2 and a band encompassing the whole short arm of chromosome 10. These two bands inH. abei were the shortest among those of the variousHynobius species that have been examined. Otherwise no differences could be detected betweenH. abei and seven other pond-type species ofHynobius (2n=56) in terms of the banding patterns of 18 specifically identifiable pairs of their chromosomes.     

Cytogenetic observations inCeratitis capitata

Summary The 2n=10+XX/XY complement ofC. capitata includes3 pairs of metacentric and 2 pairs of submetacentric autosomes; theX andY chromosomes are acrocentrics. The sex chromosomes do not pair somatically during mitotic prophase, and, using the C-banding technique, band more extensively than the autosomes. Male meiosis may be achiasmate; there is no leptotene, zygotene or diplotene.Material kindly supplied by Dr.D. A. Lindquist, I.A.E.A./FAO Vienna, Austria.     

The karyotype,C-bands and AgNO3-bands of a lungless salamander from Korea:Onychodactylus fischeri (Boulenger) (Amphibia,Urodela)

The karyotype of a lungless salamander,Onychodactylus fischeri, from Korea was analyzed and compared with that of the Japanese congeneric species,O. japonicus. In both species the diploid karyotype consists of78 chromosomes, including 6 pairs of large chromosomes, 6 pairs of medium-sized ones, and the remaining 27 pairs of microchromosomes. The chromosome number ofO. fischeri, 2n=78, is, like that ofO. japonicus, the largest so far reported in the order Urodela. C-banding showed that constitutive heterochromatin inO. fischeri was mainly in the centromeric regions and near the secondary constrictions of the large chromosomes. AgNO₃-bands were located in the secondary constrictions associated with C-band heterochromatin.     

Un nouveau système polymorphe robertsonien chez une nouvelle espèce de «Leggada» (Mus goundae Petter)

Summary A sample of 6 Leggada from N'Délé (Central African Republic) morphologically different from all these studied up to now, constitue a new species, which will be described by Dr F.Petter asMus goundae Petter. The caryological analysis reveals a new robertsonian polymorphical system. The diploïd numbers are 2N=16, 17, 18 or 19, whereas theN.F. is constant and equal to 30. The 3 first pairs of autosomes, constituted by SM or MC elements are identical in the 4 types, as well as pairs V (MC) and VI (AC) morphologically constant by all individuals. The robertsonian mechanisms, from which polymorphism originates, take place at pairs IV, VII and VIII. The fourth pair, while heterozygote by 2N=19, assembling one MC and two AC elements, is homozygote and MC by 2N=18, 17 and 16; pairs VII and VIII are both constituted by two AC in the cases of 19 and 18 chromosomes; to form caryotypes with 17 and 16 chromosomes these 2 pairs will fusion: by 2N=17 the mutation is heterozygote (1 MC and 2 AC) and it becomes homozygote by 2N=16 giving birth to 2 MC. The sexual chromosomes are from TR Type (X MC andY SM).From these observations arises the problem of low chromosome numbers (16–20) which shall be discussed in a further publication.     

Trends of karyological evolution in Pelobatoid frogs

Summary The Pelobatids have a basal karyotype of 26 chromosomes, with 6 pairs of large and 7 of small chromosomes (6+7). From this karyotype, shown byLeptobrachium, Pelobates andScaphiopus, those ofMegophrys andSpea (5+8) may be derived, as well as that ofL. pelodytoides, with only 24 chromosomes.Pelodytes has 24 chromosomes and a karyotype 7+5 differing from that of typical Pelobatids under several respects.Research supported by a contribution from the Italian C. N. R.     

The karyotypes of the Corsican and Sardinian mountain salamanders,Euproctus montanus andE. platycephalus (Urodela: Salamandridae)

Summary The chromosomes ofEuproctus montanus andE. platycephalus were studied by means of the C-banding method and the AS-SAT technique which are useful for identifying the single pairs of the complement and for recognizing nucleolar organizer regions. According to the morpho-structural characteristics shown by the specific karyotypes, it has been possible to draw some cytotaxonomic deductions concerning the karyological evolution within the insular group.This work was supported by grant CT 76.01271.04/115.3822 from C.N.R., Rome.     

The karyotype and genome structure of the pirate perchAphredoderus sayanus (Aphredoderidae: Teleostei)

Summary The standard karyotype, genome size (DNA content), and genomic DNA base composition and distribution of the relict paracanthopterygian fish,Aphredoderus sayanus, were investigated. Several features of theA. sayanus genome appear to be derived rather than primitive conditions. These include a large number (at least 10 pairs) of bi-armed chromosomes, a low genome size, and high DNA asymmetry. This may indicate thatA. sayanus is not a typical paracanthopterygian fish in terms of its genome structure.     

Chromosome arrangement throughout mitosis and interphase inAllium sativum (Liliaceae)

Summary Allium sativum (garlic) root-tip chromosomes were subjected to a C-banding procedure. In addition to the nucleolar bands reported previously in this species, bands which are telomeric or close to the telomeres have been detected in some pairs. This has allowed us to analyze the arrangement of chromosomes during interphase.     

Karyological pattern of two Chilean lizards species of the genusLiolaemus (sauria; iguanidae)

Summary The karyotypes of Chilean lizardsLiolaemus pictusandLiolaemus cyanogaster is described for the first time. Both species possess 34 chromosomes; 6 pairs of macrochromosomes and 11 pairs of microchromosomes. Karyologically it is possible to differenciate this species because the pair No. 2 is metacentric (m) inL. pictusand submetacentric (sm) inL. cyanogaster. It is shortly discussed the signification of formule 2n=34 for the species ofLiolaemus analized karyologically and its possible mechanism of acquisition.     

A new chromosome number forBombina (Anura,Discoglossidae)

Summary The karyotype of a primitive discoglossid anuran,Bombina maxima, native to southwestern China, has 2n=28 chromosomes with 6 large and 8 small bi-armed homologous pairs. This is a higher chromosome number than described for otherBombina species, all of which have 2n=24.     

Karyological relationships between the Cryptobranchid salamanders

Summary The 3 living Cryptobranchids (Andrias japonicus, A. davidianus andCryptobranchus alleganiensis) show 2n=60 and nuclear DNA amounts of respectively 92.9, 100.1 and 112.5 pg. Karyologically, the 2 genera differ in the morphology of 2 chromosome pairs. The hypotheses are advanced that either theCryptobranchus karyotype is derived from that ofAndrias through an unequal translocation, or the karyotypes of both genera are derived from that of a common (perhaps hynobiid) ancestor with at least 62 chromosomes.Research supported by a contribution from the Italian C.N.R.     

Karyotype and chromosome banding in the Turkish desert woodlouseDesertellio elongatus (Crustacea,Isopoda, Oniscidea)

The karyotype ofD. elongatus was investigated by means of C-banding, silver staining, and mithramycin-and quinacrine fluorescent staining. The diploid chromosome number is 2n=50. C-banding shows pericentromerically localized constitutive heterochromatin in every chromosome. Two of the chromosome pairs carry two telomeric nucleolus organizer regions each. No heteromorphic sex chromosomes were found.     

Cytotaxonomy of the Seychelles tree frog,Megalixalus seychellensis (Duméril and Bibron) (Amphibia: Hyperoliidae)

Summary The Seychelles tree frog,Megalixalus seychellensis has 2n=24 chromosomes of gradually decreasing length. Pairs 2, 3, and 4 are submetacentric, and the remaining pairs are metacentric. The karyotype affirms hyperoliid assignment of this species, and indicates a link between the Seychellean fauna and the African-Madagascan faunas.Research supported by the National Geographic Society.     

Chromosomal and morphological diversity in 2 populations of Asian mountain vole,Alticola lemminus Miller (Rodentia,Cricetidae)

Summary Voles from Yakutia and Chukotka were found to differ in the morphology of 3 pairs of autosomes and sex chromosomes, as well as in M³-structure and skull dimensions. This makes their conspecificity doubtful. A variation in short arm lengths of the X- and Y-chromosomes has been discovered.     

Heterochromosomen beiVipera berus L. (Viperidae,Serpentes)

Summary A dimorphic pair of chromosomes was found among the macrochromosomes in mitosis of females ofVipera berus L. It corresponds to a pair of medium-sized chromosomes in the male. The conclusion is drawn that females are heterogametic (ZW-type), males being homogametic (ZZ-type). Similar observations were made inVipera aspis L.,Natrix natrix L., andNatrix maura L.     

Caryotypes de quelques hybrides interspécifiques dePitymys (Mammalia,Rodentia)

Summary The Robertsonian polymorphism ofPitymys subterraneus involves only 1 pair of metacentric autosomes. The crosses of forms with 52, 53 and 54 chromosomes do not show any differences in their reproductive rate. So a single autosome trivalent does not affect the fecondity. Many hybrids have been obtained betweenP. subterraneus (2N=52 or 54) andP. multiplex (2N=48) with 50 or 51 chromosomes, respectively. Even with a heterogenous karyotype they are not entirely sterile. 2 progeny were produced from back-crosses. The 2 parental species seem to result from recent speciation. Only fecondation or embryogenesis occurs in crossingP. duodecimcostatus withP. subterraneus orP. multiplex. The chromosome complement of 1 hybrid embryo ofP. duodecimcostatus (2N=62)×P. multiplex (2N=48) has been studied showing 55 chromosomes.P. duodecimcostatus appears to belong to a more distant evolutionary group.     

C-band differentiation between the chromosomes of two subspecies of the chironomid midgeChironomus thummi

Summary The metaphase chromosomes ofChironomus th. thummi contain approximately 17% more pericentric C-band heterochromatin than the chromosomes ofChironomus th. piger with 11% heterochromatin. InCh. th. thummi, the proportion of heterochromatin appeared to be much larger in metaphase chromosomes than in polytene chromosomes. This discrepancy is interpreted as being due to the specific chromosome organization and not as the result of an underreplication of heterochromatin during polytenization.     

The chromosomes ofPasseromyia heterochaeta Villeneuve (Muscidae: Diptera)

Summary The 2 n=10 complement ofPasseromyia heterochaeta Villeneuve consists of 4 pairs of metacentric chromosomes and 1 pair of dots. The evolutionary implications of 2 n=10 in the tribe Phaoniini (Fam. Muscidae) are discussed.Acknowledgments. Thank are due to Dr Adrian C. Pont of British Museum (Natural Histoty), London for identifying our speciens through the courtesy of Dr Rokuro Kano, Dean Faculty of Medicine, Tokyo Medical and Dental University Tokyo, Japan. We also thank Dr U.S. Srivastava, Professor and Head, Dept. of Zoology, Univ. of Allahabad for providing the necessary laboratory faclities.     

Cytotaxonomy of the myobatrachid frogs of the genusLimnodynastes

Summary 4 of the 5 species ofLimnodynastes of theperoni group show 2n=24. Onlysalmini has 2n=22, thus resembling the species ofPlatyplectron (thedorsalis andornatus complexes) which all show 22 chromosomes. This 2nd group also includes species (ornatus) with very low DNA amounts. From a karyological point of view, the species of thePlatyplectron (plus eventuallysalmini) group appear more differentiated than the species of theperoni group, from which they have probably arisen.Research partly supported by a contribution from C.N.R., Rome.     

Cytologie comparée des Muridae. L'origine des Ellobii

Summary (1) The present paper deals with the chromosomial cytology of 11 species and underspecies ofMuridae. (2) The diploïd number being the same (2N=42), there are striking differences between two species ofBandicota, B. indica showing about 20 big metacentric chromosomes which are lackingB. bengalensis. (3)Meriones blackleri is characterized by 72 chromosomes, the species previously described possessing either 44 or 60 elements. (4) The study ofPhenacomys ungava confirms the view that 56 (54) is the primitive number in theMicroti. There is an interesting parallelism between the morphological and the cytological data. (5) A missing link betweenMicroti andEllobii has been found inMicrotus oregoni which possesses 17 chromosomes, its digamety belonging to the typeX-O, X-X. (6) Owing to the fact thatM. oregoni is more fossorial than the otherMicrotus, it is a morphological intermediate betweenMicroti andEllobii. (7) The genusChilotus (Baird) is also fully valid.