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Reproductive Isolation Between Two Species Of Topminnow, Fundulus Olivaceus And F. Euryzonus., Thomas Allen Blanchard
Reproductive Isolation Between Two Species Of Topminnow, Fundulus Olivaceus And F. Euryzonus., Thomas Allen Blanchard
LSU Historical Dissertations and Theses
Fundulus olivaceus and F. euryzonus are sister species that commonly occur syntopically in the Amite and Tangipahoa River drainages in Louisiana and Mississippi. Although the habitats of the two species are quite similar, and the timing of their reproductive activity overlaps extensively, no natural hybrids between them have been documented. I examined physiological, as well as behavioral, factors that could potentially serve as effective isolating mechanisms between them. The courtship and spawning behaviors of the two species were relatively generalized and showed a number of similarities. Under forced mating conditions in which females were allowed to associate with heterospecific males …
Population Structure And Phylogenetic History Of The Lake Malawi Cichlid Species Flock, Jeffrey Alan Markert
Population Structure And Phylogenetic History Of The Lake Malawi Cichlid Species Flock, Jeffrey Alan Markert
Doctoral Dissertations
The cichlid species "flocks" which are endemic to the East African Rift Valley are characterized by frequent lineage splitting events which have led to the rapid evolution of high levels of taxonomic diversity. Changes in water level cause these habitat patches to be chronically unstable, hypothetically speeding the process of genetic differentiation through the combined effects of genetic drift and selection. Allele frequencies at four simple sequence repeat loci indicate low levels of gene flow in two rock dwelling fish species, Melanochromis auratus and Labeotropheus fuelleborni, collected from the Nankumba Peninsula in southern Lake Malawi. Small interruptions in habitat cause …
Molecular Systematics Of Selected Members Of The Black Basses, Genus Micropterus, With Concentration On The Spotted Bass (M. Punctulatus) Species Complex., Belinda Fuller
LSU Historical Dissertations and Theses
This study examined genetic relationships among selected populations of black basses. These centrarchid fishes, separated by both physical barriers (land formations) and distance, have shown varying degrees of differentiation, but retain many morphometric characters in common. Eight populations representing four taxa and geographical extremes in the genus Micropterus, with concentration on the spotted bass complex, were selected and evaluated for biochemical genetic characters. This study examined two species and two subspecies of spotted basses. The type species from Kentucky represented Micropterus punctulatus punctulatus; a population from Alabama represented M. p. henshalli. A Texas population, previously classified as conspecific with spotted …
A Review Of The North American Squalodontidae (Mammalia, Cetacea)., Alton Cline Dooley Jr
A Review Of The North American Squalodontidae (Mammalia, Cetacea)., Alton Cline Dooley Jr
LSU Historical Dissertations and Theses
All available North American specimens of squalodont whales were examined to determine species assignments, and to determine functional aspects and ecological implications. Only two existing species of the 17 referred to Squalodontidae from North America are members of that family, Squalodon atlanticus and Squalodon calvertensis. Of these two species, only S. calvertensis is based on adequate material for consideration as a valid species. Squalodon calvertensis is redescribed, based on the material which has been collected since 1923. These specimens indicate that the species is found from New Jersey to North Carolina, in the Miocene Kirkwood, Calvert, and Pungo River Formations. …