8/2/2019 en_v5n2a31

1/1

Genetics diversity and population structure of crocodilians black caiman

(Melanosuchus niger) and spectacled caiman (Caiman crocodilus) in Amazon

William Rangel Vasconcelos

AbstractThe Amazonian crocodilians are included in threegenera, Caiman, Melanosuchus and Paleosuchus.Within these genera, two species deserve specialattention because they were overexploited in pastdecades; these are the black caiman (Melanosuchusniger) and spectacled caiman (Caiman crocodilus), thetwo more abundant crocodilians in the BrazilianAmazon. The objective of this research was toquantify the degree of genetic variability andpopulation structure of the black caiman and thespectacled caiman using a matrilineal marker(mitochondrial gene cytochrome b), which tocontribute information that can be used for

management and for conservation of these species.Approximately 1080 bp were sequenced for a total of125 individuals ofC. crocodilus and 132 ofM. nigerrepresenting 9 and 11 localities of each species,respectively. Sampling localities were distributedthroughout the Brazilian Amazon, as well as Peru,Ecuador and French Guyana. Results of populationgenetic analyses demonstrate that some populations ofboth species are in a process of a demographicexpansion shown by a relatively greater number ofsingleton haplotypes. Both species have high genediversity but low nucleotide diversity. The NestedClade Phylogeographical Analysis indicated range

expansion, long-distance colonization and pastfragmentation as possible historic-demographic eventC. crocodilus populations. NCPA results forM. nigershowed no significant historical events. However, in

M. niger a significant correlation between geneticdivergence and geographic distance also was identifiedby the Mantel test, indicating isolation by distance.The isolated populations of the Atlantic drainagespotentially represent evolutionary units differentiatedfrom the Amazon basin populations.

Key-words: genetic variability, crocodilians,Melanosuchus niger, Caiman crocodilus, mtDNA, cyt.b, population fragmentation

FICHA CATALOGRFICA

BIBLIOTECA DO INSTITUTO NACIONAL DEPESQUISAS DA AMAZNIAVasconcelos, William Rangel

Diversidade gentica e estrutura populacionaldos crocodilianos jacar-a (Melanosuchus niger) ejacar-tinga (Caiman crocodilus) da Amaznia. --2005.

xviii, 78 f. : il.Dissertao (mestrado)INPA/UFAM, 2005.1. Amaznia 2. Melanosuchus niger 3. Caiman

crocodilus 4. Filogeografia 5. Citocromo b 6.

Freqncia haplotpica 7. Gentica da conservao.CDD 19. ed. 597.980415

http://www.biotaneotropica.org.br