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Abstract

The Kemp's ridley sea turtle (Lepidochelys kempi) is restricted to the warm temperate zone of the North Atlantic Ocean, whereas the olive ridley turtle (L. olivacea) is globally distributed in warm-temperate and tropical seas, including nesting colonies in the North Atlantic that nearly overlap the range of L. kempi. To explain this lopsided distribution, Pritchard (1969) proposed a scenario in which an ancestral taxon was divided into Atlantic and Pacific forms (L. kempi and L. olivacea, respectively) by the Central American land bridge. According to this model, the olive ridley subsequently occupied the Pacific and Indian Oceans and recently colonized the Atlantic Ocean via southern Africa. To assess this biogeographic model, a 470 bp sequence of the mtDNA control region was compared among 89 ridley turtles, including the sole L. kempi nesting population and 7 nesting locations across the range of L. olivacea. These data confirm a fundamental partition between L. olivacea and L. kempi (p = 0.052-0.069), shallow separations within L. olivacea (p = 0.002-0.031), and strong geographic partitioning of mtDNA lineages. The most divergent L. olivacea haplotype is observed in the Indo-West Pacific region, as are the central haplotypes in a parsimony network, implicating this region as the source of the most recent radiation of olive ridley lineage. The most common olive ridley haplotype in Atlantic samples is distinguished from an Indo-West Pacific haplotype by a single nucleotide substitution, and East Pacific samples are distinguished from the same haplotype by two nucleotide substitutions. These shallow separations are consistent with the recent invasion of the Atlantic postulated by Pritchard (1969), and indicate that the East Pacific nesting colonies were also recently colonized from the Indo-West Pacific region. Molecular clock estimates place these invasions within the last 300,000 years.

Strong site fidelity and longer internesting interval for solitary nesting olive ridley sea turtles in Brazil

“…If the Atlantic coast was the last to be colonized, then genetic divergence could have occurred during the geographic expansion, justifying differences in reproductive patterns between different populations. Distinct genetic compositions have been found in Atlantic olive ridley populations (Bowen et al 1998). They exhibit exclusive mitochondrial DNA alleles F and E; however, relationships between genotype and phenotype have not yet been made.…”

“…The observed longer internesting intervals at Sergipe could also be related to phylogenetic differences of this population. Previous studies suggested that after the evolutionary divergence of the two Lepidochelys species (after Panama's isthmus closed), olive ridleys expanded their geographic distribution from the Indio-West Pacific region to the East Pacific and, more recently, to the Atlantic Ocean (Pritchard 1969a, b;Hughes 1972;Bowen et al 1998). If the Atlantic coast was the last to be colonized, then genetic divergence could have occurred during the geographic expansion, justifying differences in reproductive patterns between different populations.…”

Some cats of a long 1930s

“…At the foot it swayed off like a leopard, one rippling curve of malignity. 22 Benito might apparently be a sweet pet who acquiesces to being wrapped in scarves, but he is of the same species as this all-knowing flâneur-feline, a creature who mocks Emmeline with a leer and vanishes with his very form containing sinister and bewitching meaning. At the close of the novel Emmeline and Markie leave for their liebestod death-drive up the Great North Road; but Emmelinedespite leaving behind her driving gloveshas time to stroke Benito.…”

Mitochondrial genomes and genetic structure of the Kemp's ridley sea turtle (Lepidochelys kempii)

“…One way to predict the ability of a species to adapt to environmental change is to quantify the genetic variability within the population (Frankham, 1996). Variation within sea turtle DNA is commonly studied using microsatellite markers (Aggarwal et al, 2004), nuclear markers (Bowen et al, 1998;Bowen, Meylan, & Avise, 1991), single nucleotide polymorphisms (Hurtado et al, 2016), or the mitochondrial control region (Gaos et al, 2016;Matsuzawa et al, 2016). Previous studies of Kemp's ridleys have utilized various nuclear markers to determine divergence from Olive ridley (Lepidochelys olivacea) sea turtles (Bowen et al, 1998(Bowen et al, , 1991, determine genetic diversity between nesting colonies (Kichler, 1996), document nesting (Johnson, Bass, Libert, Marshall, & Fulk, 1999), and detect multiple paternity in clutches (Kichler, Holder, Davis, Márquez-M, & Owens, 1999).…”

“…The Kemp's ridley (Lepidochelys kempii), the world's most endangered sea turtle species (Burchfield, 2005), is restricted primarily to the Gulf of Mexico (GoM) and parts of the Northern Atlantic (Bowen et al, 1998). By the mid-1980s, the Kemp's ridley had suffered a dramatic population decline, and it is estimated that fewer than 300 females nested in 1985 (National Marine Fisheries Service [NMFS] et al, 2011).…”