ABSTRACT
Geographic variation in external morphology is thought to reflect an interplay between genotype and the environment. Morphological variation has been well-described for a number of cetacean species, including the bottlenose dolphin (Tursiops truncatus). In this study we analyzed dorsal fin morphometric variation in coastal bottlenose dolphins to search for geographic patterns at different spatial scales. A total of 533 dorsal fin images from 19 available photo-identification catalogs across the three Mexican oceanic regions (Pacific Ocean n = 6, Gulf of California n = 6 and, Gulf of Mexico n = 7) were used in the analysis. Eleven fin shape measurements were analyzed to evaluate fin polymorphism through multivariate tests. Principal Component Analysis on log-transformed standardized ratios explained 94% of the variance. Canonical Discriminant Function Analysis on factor scores showed separation among most study areas (p < 0.05) with exception of the Gulf of Mexico where a strong morphometric cline was found. Possible explanations for the observed differences are related to environmental, biological and evolutionary processes. Shape distinction between dorsal fins from the Pacific and those from the Gulf of California were consistent with previously reported differences in skull morphometrics and genetics. Although the functional advantages of dorsal fin shape remains to be assessed, it is not unlikely that over a wide range of environments, fin shape may represent a trade-off among thermoregulatory capacity, hydrodynamic performance and the swimming/hunting behavior of the species.
ABSTRACT
Elaeis oleifera (Kunth) Cortés (American oil palm) has advantageous characteristics for hibridization with E. guineensis which vary among populations. In order to contribute to population discrimination, we studied pollen morphology of ten Amazonian populations (Acajatuba, Amatari, Autazes, BR-174, Careiro, Manicoré, Maués, Moura, Novo Aripuanã, Tefé). The acetolysis method was used to eliminate cell contents and enable observations on pollen size, shape, aperture and exine surface. Pollen grains from the Novo Aripuanã population had the largest mean grain size (49 m) and populations from Amatari, BR-174 and Moura the smallest (42.5 to 44 m). Pollen is elliptic or piriform, aperture type is monocolpate and exine surface is microreticulate. Pollen grains with morphological abnormalities were also found. Pollen morphology discriminated three groups of Amazonian populations and offers an important tool for population discrimination, especially when associated with other analyses.
Elaeis oleifera (Kunth) Cortés - Arecaceae (caiaué) apresenta características vantajosas para a hibridação com o dendê E. guineensis que variam entre populações. Com o objetivo de contribuir para a discriminação de populações amazônicas, caracterizou-se a morfologia do pólen de dez populações de caiaué (Acajatuba, Amatari, Autazes, BR-174, Careiro, Manicoré, Maués, Moura, Novo Aripuanã e Tefé). Utilizou-se o método da acetólise para eliminação do conteúdo celular e observou-se o tamanho, forma, abertura e superfície dos grãos de pólen. A população Novo Aripuanã apresentou maior tamanho médio dos grãos de pólen (49,0 m) e as populações Amatari, BR-174 e Moura os menores (42,5 a 44,0 m). Os grãos de pólen são elípticos ou piriformes, com abertura monocolpada e superfície microrreticulada. Observou-se, também, anormalidades morfológicas em alguns grãos. A morfologia polínica separou as populações amazônicas em três grupos e, quando associada a outras análises (isoenzimas e DNA), pode representar uma ferramenta importante na discriminação de populações.
ABSTRACT
Elaeis oleifera (Kunth) Cortés (American oil palm) has advantageous characteristics for hibridization with E. guineensis which vary among populations. In order to contribute to population discrimination, we studied pollen morphology of ten Amazonian populations (Acajatuba, Amatari, Autazes, BR-174, Careiro, Manicoré, Maués, Moura, Novo Aripuanã, Tefé). The acetolysis method was used to eliminate cell contents and enable observations on pollen size, shape, aperture and exine surface. Pollen grains from the Novo Aripuanã population had the largest mean grain size (49 m) and populations from Amatari, BR-174 and Moura the smallest (42.5 to 44 m). Pollen is elliptic or piriform, aperture type is monocolpate and exine surface is microreticulate. Pollen grains with morphological abnormalities were also found. Pollen morphology discriminated three groups of Amazonian populations and offers an important tool for population discrimination, especially when associated with other analyses.
Elaeis oleifera (Kunth) Cortés - Arecaceae (caiaué) apresenta características vantajosas para a hibridação com o dendê E. guineensis que variam entre populações. Com o objetivo de contribuir para a discriminação de populações amazônicas, caracterizou-se a morfologia do pólen de dez populações de caiaué (Acajatuba, Amatari, Autazes, BR-174, Careiro, Manicoré, Maués, Moura, Novo Aripuanã e Tefé). Utilizou-se o método da acetólise para eliminação do conteúdo celular e observou-se o tamanho, forma, abertura e superfície dos grãos de pólen. A população Novo Aripuanã apresentou maior tamanho médio dos grãos de pólen (49,0 m) e as populações Amatari, BR-174 e Moura os menores (42,5 a 44,0 m). Os grãos de pólen são elípticos ou piriformes, com abertura monocolpada e superfície microrreticulada. Observou-se, também, anormalidades morfológicas em alguns grãos. A morfologia polínica separou as populações amazônicas em três grupos e, quando associada a outras análises (isoenzimas e DNA), pode representar uma ferramenta importante na discriminação de populações.