The chromosomes of a male manatee

Loughman, William D.; Frye, F. L.; Herald, Earl S.

doi:10.1111/j.1748-1090.1970.tb01320.x

Cited by 14 publications

(12 citation statements)

References 2 publications

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“…This species is distinguished from T. manatus by a range of morphological characters including lack of nails on the pectoral flippers, reduced number of dorsal vertebrae, smaller and more complex molars, and thickened supraoccipital (Domning & Hayek 1986). In addition, T. inunguis has a higher diploid chromosome number (56 compared to 48 in T. manatus ; Loughman et al 1970; White et al 1976). T. inunguis is distributed along the Amazon River and adjacent coastal estuaries, and it is not known what factors maintain the apparent parapatry of T. inunguis and T. manatus at the mouth of the Amazon River (Domning 1981).…”

Section: Discussionmentioning

confidence: 99%

Phylogeography of the West Indian manatee (Trichechus manatus): how many populations and how many taxa?

et al. 1998

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To resolve the population genetic structure and phylogeography of the West Indian manatee (Trichechus manatus), mitochondrial (mt) DNA control region sequences were compared among eight locations across the western Atlantic region. Fifteen haplotypes were identified among 86 individuals from Florida, Puerto Rico, the Dominican Republic, Mexico, Columbia, Venezuela, Guyana and Brazil. Despite the manatee's ability to move thousands of kilometers along continental margins, strong population separations between most locations were demonstrated with significant haplotype frequency shifts. These findings are consistent with tagging studies which indicate that stretches of open water and unsuitable coastal habitats constitute substantial barriers to gene flow and colonization. Low levels of genetic diversity within Florida and Brazilian samples might be explained by recent colonization into high latitudes or bottleneck effects. Three distinctive mtDNA lineages were observed in an intraspecific phylogeny of T. manatus, corresponding approximately to: (i) Florida and the West Indies; (ii) the Gulf of Mexico to the Caribbean rivers of South America; and (iii) the northeast Atlantic coast of South America. These lineages, which are not concordant with previous subspecies designations, are separated by sequence divergence estimates of d = 0.04-0.07, approximately the same level of divergence observed between T. manatus and the Amazonian manatee (T. inunguis, n = 16). Three individuals from Guyana, identified as T. manatus, had mtDNA haplotypes which are affiliated with the endemic Amazon form T. inunguis. The three primary T. manatus lineages and the T. inunguis lineage may represent relatively deep phylogeographic partitions which have been bridged recently due to changes in habitat availability (after the Wisconsin glacial period, 10 000 B P), natural colonization, and human-mediated transplantation.

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Section: Discussionmentioning

confidence: 99%

Phylogeography of the West Indian manatee (Trichechus manatus): how many populations and how many taxa?

et al. 1998

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“…4.8. Chromosomes-The diploid chromosome number is reported to be 56 in T. inunguis (Loughman et al 1970) and 48 in T. manatus (White et al 1976); the number in T. senegalensis is unknown.…”

Section: Skin Textwe-tmentioning

confidence: 99%

INTERSPECIFIC AND INTRASPECIFIC MORPHOLOGICAL VARIATION IN MANATEES (SIRENIA: TRICHECHUS)

Domning

Hayek²

1986

Marine Mammal Science

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The three living species of Trichechus are clearly defined and well exemplify the degree of variability and taxonomic value of morphological characters in a well-understood mammalian genus. Statistical analysis of the largest sample of manatee skulls yet studied has allowed us to identify small suites of characters that effectively distinguish these species. The two subspecies of T. manatus proposed by Hatt (1934) can likewise be distinguished, and their use as taxonomic categories seems justified. This suggests that the cool winters of the northern Gulf Coast, on the one hand, and the deep water and strong currents of the Straits of Florida, on the other, are effective barriers to gene flow between Florida and Antillean manatees. Alleged taxonomic distinctions within T. senegalensis, however, have no demonstrated basis. No significant sexual dimorphism was detected in skulls of any of the species. Many interspecific differences can be correlated with feeding ecology, but others remain unexplained. Features of tooth crown morphology are among the most constant characters examined, but some osteological characters are equally good. T. manatas and T. senegalensis (which are phenetically the most similar) also seem to share a more recent common ancestor than either does with T. inunguis. However, the three species probably separated from each other at nearly the same time. T. inunguis has since become the most derived species, while T. senegalensis has changed the least.

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“…Solid stained chromosome studies were completed on a limited number of individual manatees, establishing the chromosome number as 2N = 48 for the Florida manatee [9,10] and 2N = 56 for the Amazonian manatee ( Trichechus inunguis ) [11]. Following solid staining, chromosome-banding procedures allowed for the identification of individual chromosome regions.…”

Section: Introductionmentioning

confidence: 99%

Chromosome painting in the manatee supports Afrotheria and Paenungulata

et al. 2007

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Background: Sirenia (manatees, dugongs and Stellar's sea cow) have no evolutionary relationship with other marine mammals, despite similarities in adaptations and body shape. Recent phylogenomic results place Sirenia in Afrotheria and with elephants and rock hyraxes in Paenungulata. Sirenia and Hyracoidea are the two afrotherian orders as yet unstudied by comparative molecular cytogenetics. Here we report on the chromosome painting of the Florida manatee.

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The chromosomes of a male manatee

Cited by 14 publications

References 2 publications

Phylogeography of the West Indian manatee (Trichechus manatus): how many populations and how many taxa?

Phylogeography of the West Indian manatee (Trichechus manatus): how many populations and how many taxa?

INTERSPECIFIC AND INTRASPECIFIC MORPHOLOGICAL VARIATION IN MANATEES (SIRENIA: TRICHECHUS)

Chromosome painting in the manatee supports Afrotheria and Paenungulata

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