View
223
Download
0
Category
Tags:
Preview:
Citation preview
Caitlyn Roan, Tara Connor, and John Grimsley
The Blenny: OphioblenniusOne of the most
diverse suborders of teleost fishes723 species127 genera6 families
The Blenny: OphioblenniusFamily BlenniidaeAlgivorous fishInhabit shallow, rocky
shores and reefsTypical reef fish life
historyBenthic eggs that
hatch after 5 daysLong, planktonic
larval phase of approx. 50 days
The Blenny: Ophioblennius
This species lives on the Caribbean side of the Panama Isthmus This species lives on the Pacific
side of the Panama Isthmus
The Blenny: OphioblenniusO. steindachneri
divided into 2 subspeciesO. s. steindachneri
(1)O. s. clippertonensis
(2)O. atlanticus divided
into 2 subspeciesO. a. atlanticus (3)O. a. macclurei (4)
Question 1When did the Panama Isthmus form and was
it the actual cause of separation of the two species of blennies?
The Panama IsthmusCommonly used in evolutionary studies to
evaluate morphological, ecological, and molecular divergences
Rose ~3.1 MYAVicariance hypothesis (Rosen)Dispersal hypothesis (Briggs)Ancestral species, Ophioblennius, separated
7 MYA during initial shoaling
The Panama Isthmus
The Atlantic Redlipped BlennyOphioblennius atlanticus & macclurei
The Pacific Fanged BlennyOphioblennius steindachneri &
clippertonensis
Question 2What are the different biogeographic regions
and does the presence of an oceanographic barrier (Panama Isthmus) influence speciation of the blennies?
Pacific VS Atlantic OceansPacific Atlantic
Reefs widely scatteredClosed ocean basinStable currentsIslands provided
stepping stones in range expansion
Low rates of gene flow
Reefs continuous along coastline
Open ocean basinUnstable currentsHigh rates of gene
flow
Biogeographic Regions:Study by Muss et al.
A study by Muss et al.177 individuals from
10 Atlantic & 4 Pacific locations
Segments of mitochondrial DNA cytochrome b gene were obtained
Genetic variation estimated from haplotype diversities & nucleotide diversities
A study by Muss et al.Sequence comparisons revealed 176 variable
sites with 272 transitions and 39 transversions, a total of 122 haplotypes in 171 individuals
To compare populations an exact test of population differentiation was conducted using haplotypes defined by transversion-differences only
The 39 observed transversions defined 25 haplotypes, including from one to five transversion haplotypes per location
A study by Muss et al.
Haplotypes
Locations
A study by Muss et al.
ConclusionsO. atlanticus & O. steindachneri shared
common ancestor 7 MYAThe 2 species of blenny were separated
before closure of the Panama IsthmusAfter the closure, an oceanographic barrier,
biogeographic provinces, and natural factors influenced speciation
Populations in close proximity to one another show higher levels of gene flow and lower levels of population differentiationPopulations closer to one another are more
similar
Further ResearchObtain samples of Ophioblennius atlanticus &
Ophioblennius steindachneri from each of the different biogeographic regions and place them in tanks to see if they will mate with one another
SourcesMuss, A, D.R. Robertson, C.A. Stepien, P Wirtz,
and B.W. Bowen. "Phylogeography of opioblennius:
the role of ocean currents and geography in reef fish evolution." Society for the Study of Evolution 55.3 (2001): 561-572. Web. 13 Apr 2010. <https://illiad.radford.edu/illiad.dll?Action=10&F orm=75&Value=264074>.
Springer, V.G. 1962. A review of the Blenniid fishes of the genus Ophioblennius Gill. Copeia 1962:426-433.
Recommended