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Phylogeographic structure and northward range expansion in the barnacle Chthamalus fragilis.

Govindarajan AF, Bukša F, Bockrath K, Wares JP, Pineda J - PeerJ (2015)

Bottom Line: The barnacle Chthamalus fragilis is found along the US Atlantic seaboard historically from the Chesapeake Bay southward, and in the Gulf of Mexico.We found significant genetic structure between northern and southern populations.While the distances between clades do not suggest cryptic speciation, selection and dispersal barriers may be driving the observed structure.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biology Department, Woods Hole Oceanographic Institution , Woods Hole, MA , USA.

ABSTRACT
The barnacle Chthamalus fragilis is found along the US Atlantic seaboard historically from the Chesapeake Bay southward, and in the Gulf of Mexico. It appeared in New England circa 1900 coincident with warming temperatures, and is now a conspicuous member of rocky intertidal communities extending through the northern shore of Cape Cod, Massachusetts. The origin of northern C. fragilis is debated. It may have spread to New England from the northern end of its historic range through larval transport by ocean currents, possibly mediated by the construction of piers, marinas, and other anthropogenic structures that provided new hard substrate habitat. Alternatively, it may have been introduced by fouling on ships originating farther south in its historic distribution. Here we examine mitochondrial cytochrome c oxidase I sequence diversity and the distribution of mitochondrial haplotypes of C. fragilis from 11 localities ranging from Cape Cod, to Tampa Bay, Florida. We found significant genetic structure between northern and southern populations. Phylogenetic analysis revealed three well-supported reciprocally monophyletic haplogroups, including one haplogroup that is restricted to New England and Virginia populations. While the distances between clades do not suggest cryptic speciation, selection and dispersal barriers may be driving the observed structure. Our data are consistent with an expansion of C. fragilis from the northern end of its mid-19th century range into Massachusetts.

No MeSH data available.


Geographic distribution of the three major haplogroups.
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fig-3: Geographic distribution of the three major haplogroups.

Mentions: Haplogroups differed in their geographic distribution (Table 5; Fig. 3). Haplogroup 1 was present in all New England sites and most southern sites, except Savannah and Tampa. Haplogroup 2 was well-represented in the Massachusetts and Rhode Island sites, and also present in Virginia, but not in any of the more southern sites. Haplogroup 3 was present in the Sandwich, Truro, and Woods Hole, Massachusetts sites, but not in Rhode Island. It was the most abundant haplogroup in all of the southern sites. In Savannah and Tampa, it was the only haplogroup found. The Mantel test indicated significant isolation by distance (p < 0.001).


Phylogeographic structure and northward range expansion in the barnacle Chthamalus fragilis.

Govindarajan AF, Bukša F, Bockrath K, Wares JP, Pineda J - PeerJ (2015)

Geographic distribution of the three major haplogroups.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4419548&req=5

fig-3: Geographic distribution of the three major haplogroups.
Mentions: Haplogroups differed in their geographic distribution (Table 5; Fig. 3). Haplogroup 1 was present in all New England sites and most southern sites, except Savannah and Tampa. Haplogroup 2 was well-represented in the Massachusetts and Rhode Island sites, and also present in Virginia, but not in any of the more southern sites. Haplogroup 3 was present in the Sandwich, Truro, and Woods Hole, Massachusetts sites, but not in Rhode Island. It was the most abundant haplogroup in all of the southern sites. In Savannah and Tampa, it was the only haplogroup found. The Mantel test indicated significant isolation by distance (p < 0.001).

Bottom Line: The barnacle Chthamalus fragilis is found along the US Atlantic seaboard historically from the Chesapeake Bay southward, and in the Gulf of Mexico.We found significant genetic structure between northern and southern populations.While the distances between clades do not suggest cryptic speciation, selection and dispersal barriers may be driving the observed structure.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biology Department, Woods Hole Oceanographic Institution , Woods Hole, MA , USA.

ABSTRACT
The barnacle Chthamalus fragilis is found along the US Atlantic seaboard historically from the Chesapeake Bay southward, and in the Gulf of Mexico. It appeared in New England circa 1900 coincident with warming temperatures, and is now a conspicuous member of rocky intertidal communities extending through the northern shore of Cape Cod, Massachusetts. The origin of northern C. fragilis is debated. It may have spread to New England from the northern end of its historic range through larval transport by ocean currents, possibly mediated by the construction of piers, marinas, and other anthropogenic structures that provided new hard substrate habitat. Alternatively, it may have been introduced by fouling on ships originating farther south in its historic distribution. Here we examine mitochondrial cytochrome c oxidase I sequence diversity and the distribution of mitochondrial haplotypes of C. fragilis from 11 localities ranging from Cape Cod, to Tampa Bay, Florida. We found significant genetic structure between northern and southern populations. Phylogenetic analysis revealed three well-supported reciprocally monophyletic haplogroups, including one haplogroup that is restricted to New England and Virginia populations. While the distances between clades do not suggest cryptic speciation, selection and dispersal barriers may be driving the observed structure. Our data are consistent with an expansion of C. fragilis from the northern end of its mid-19th century range into Massachusetts.

No MeSH data available.