KARYOLOGY OF NORTH AMERICAN CROTALINE SNAKES (FAMILY VIPERIDAE) OF THE GENERA AGKISTRODON, SISTRURUS, AND CROTALUS

1973 ◽  
Vol 15 (3) ◽  
pp. 389-395 ◽  
Author(s):  
Earl G. Zimmerman ◽  
C. William Kilpatrick

The karyotypes of 10 species of crotaline snakes from three genera of the family Viperidae are described. All species were found to possess a diploid number of 36 with intergeneric differences involving at least two pairs of autosomes. More significant differences were found between the sex chromosomes with Agkistrodon piscivorous possessing a submetacentric W, A. contortrix possessing an acrocentric W, Sistrurus sp. possessing an acrocentric W, and all Crotalus sp. possessing a submetacentric or subtelocentric W. The chromosomal relationships of the genera are discussed in light of current thoughts on evolution in the Viperidae and chromosomal evolution in snakes.

1973 ◽  
Vol 15 (2) ◽  
pp. 355-361 ◽  
Author(s):  
C. William Kilpatrick ◽  
Earl G. Zimmerman

Four species of the water snake genus Natrix have a distinctly different pattern of chromosomal morphology than found in two species of the related genus Regina. Natrix all have a karyotype with seven pairs of large or medium-sized submetacentric autosomes, three pairs of medium-sized subtelocentric autosomes, and seven pairs of small metacentric autosomes. All have a 2n of 36 with a submetacentric Z and submetacentric or subtelocentric W. The autosomal complement of Regina consists of seven pairs of large to medium-sized submetacentrics, five pairs of medium-sized submetacentrics, and five pairs of small metacentrics. The Z and W are both submetacentric chromosomes. The sex chromosomes are easily distinguished in both genera. The relationships of Natrix and Regina and Old World Natrix are discussed, as well as chromosomal variation in closely related species in the family Colubridae.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Melquizedec Luiz Silva Pinheiro ◽  
Cleusa Yoshiko Nagamachi ◽  
Talita Fernanda Augusto Ribas ◽  
Cristovam Guerreiro Diniz ◽  
Patricia Caroline Mary O´Brien ◽  
...  

Abstract Background The Scolopacidae family (Suborder Scolopaci, Charadriiformes) is composed of sandpipers and snipes; these birds are long-distance migrants that show great diversity in their behavior and habitat use. Cytogenetic studies in the Scolopacidae family show the highest diploid numbers for order Charadriiformes. This work analyzes for the first time the karyotype of Actitis macularius by classic cytogenetics and chromosome painting. Results The species has a diploid number of 92, composed mostly of telocentric pairs. This high 2n is greater than the proposed 80 for the avian ancestral putative karyotype (a common feature among Scolopaci), suggesting that fission rearrangements have formed smaller macrochromosomes and microchromosomes. Fluorescence in situ hybridization using Burhinus oedicnemus whole chromosome probes confirmed the fissions in pairs 1, 2, 3, 4 and 6 of macrochromosomes. Conclusion Comparative analysis with other species of Charadriiformes studied by chromosome painting together with the molecular phylogenies for the order allowed us to raise hypotheses about the chromosomal evolution in suborder Scolopaci. From this, we can establish a clear idea of how chromosomal evolution occurred in this suborder.


1991 ◽  
Vol 123 (3) ◽  
pp. 501-558 ◽  
Author(s):  
Ian M. Smith

AbstractMorphological, life history, and distributional data are presented for North American species of the subgenus Stygomomonia (sensu stricto) Szalay, 1943. Adults of the seven previously recognized species are redescribed, and deutonymphs of five of these species are described for the first time. Two species, S. (s.s.) neomexicana Cook and S. (s.s.) occidentalis Cook are substantially revised on the basis of an examination of the types and extensive series of newly collected specimens. Three new species are described, S. (s.s.) californiensis on the basis of deutonymphs and adults, and S. (s.s.) imamurai and S. (s.s.) cooki on the basis of adults. A new diagnosis of the subgenus is proposed and discussed, the relationships of the various species are discussed, and a key to deutonymphs and adults of North American species is presented. New distributional data are presented for all species, and dispersal patterns from Pleistocene refugia are discussed.


2015 ◽  
Vol 146 (4) ◽  
pp. 296-305 ◽  
Author(s):  
Willam O. da Silva ◽  
Julio C. Pieczarka ◽  
Rogério V. Rossi ◽  
Horacio Schneider ◽  
Iracilda Sampaio ◽  
...  

Neacomys (Sigmodontinae) comprises 8 species mainly found in the Amazonian region. We describe 5 new karyotypes from Brazilian Amazonia: 2 cytotypes for N. paracou (2n = 56/FNa = 62-66), 1 for N. dubosti (2n = 64/FNa = 68), and 2 for Neacomys sp. (2n = 58/FNa = 64-70), with differences in the 18S rDNA. Telomeric probes did not show ITS. We provide a phylogeny using Cytb, and the analysis suggests that 2n = 56 with a high FNa is ancestral for the genus, as found in N. paracou, being retained by the ancestral forms of the other species, with an increase in 2n occurring independently in N. spinosus and N. dubosti. Alternatively, an increase in 2n may have occurred in the ancestral taxon of the other species, followed by independent 2n-reduction events in Neacomys sp. and in the ancestral species of N. tenuipes, N. guianae, N. musseri, and N. minutus. Finally, a drastic reduction event in the diploid number occurred in the ancestral species of N. musseri and N. minutus which exhibit the lowest 2n of the genus. The karyotypic variations found in both intra- and interspecific samples, associated with the molecular phylogeny, suggest a chromosomal evolution with amplification/deletion of constitutive heterochromatin and rearrangements including fusions, fissions, and pericentric inversions.


1963 ◽  
Vol 41 (9) ◽  
pp. 1331-1346 ◽  
Author(s):  
Aino Henssen

The systematic position of the genus Massalongia and the closely related genera Koerberia, Vestergrenopsis, and Placynthium in the family Peltigeraceae including lichens with hemiangiocarpic apothecia is discussed. The ontogeny of a hemiangiocarpic apothecium is described briefly. A key for the determination of the genera is provided.A general survey is given for the morphology and anatomy of the genus Massalongia. The two species, M. carnosa and M. microphylliza, are described in detail. The new combination M. microphylliza is made.


Author(s):  
Lauren Ash ◽  
Rachel Marschang ◽  
Jolianne Rijks ◽  
Amanda Duffus

Ranaviruses are large double stranded DNA viruses from the family Iridoviridae. They are globally distributed and are currently known to affect fish, reptiles and amphibians. In North America, ranaviruses are also widely distributed, and cause frequent morbidity and mortality events in both wild and cultured populations. This is a synopsys of the North American content of the 4th International Symposium on Ranaviruses held in May 2017 in Budapest, Hungary.


2006 ◽  
Vol 66 (1b) ◽  
pp. 205-210 ◽  
Author(s):  
G. G. Born ◽  
L. A. C. Bertollo

Specimens of Hoplias malabaricus from Lagoa Carioca, an isolated lake of the Rio Doce State Park (state of Minas Gerais, Brazil), were cytogenetically studied. The diploid number was found to be constant, i.e., 2n = 42 chromosomes, although two karyotypic forms were found: karyotype A, characterized by 22M + 20SM chromosomes, observed only in a male specimen, and karyotype B, characterized by 24M + 16SM + 2ST and 24M + 17SM + 1ST chromosomes in female and male specimens, respectively. This sex difference found in karyotype B is related to an XX/XY sex chromosome system. Another female specimen of H. malabaricus, also carrying karyotype A, had previously been found in the same lake. The available data indicate that two sympatric cytotypes of H. malabaricus exist in the Lagoa Carioca, with cytotype A occurring at a lower frequency and differing from cytotype B by undifferentiated sex chromosomes.


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