Transcript Ophioblennius

Caitlyn Roan, Tara Connor, and John Grimsley
The Blenny: Ophioblennius
 One of the most diverse
suborders of teleost
fishes
 723 species
 127 genera
 6 families
The Blenny: Ophioblennius
 Family Blenniidae
 Algivorous fish
 Inhabit shallow, rocky
shores and reefs
 Typical reef fish life
history
 Benthic eggs that hatch
after 5 days
 Long, 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: Ophioblennius
 O. steindachneri divided
into 2 subspecies
 O. s. steindachneri (1)
 O. s. clippertonensis (2)
 O. atlanticus divided into
2 subspecies
 O. a. atlanticus (3)
 O. a. macclurei (4)
Question 1
 When did the Panama Isthmus form and was it the
actual cause of separation of the two species of
blennies?
The Panama Isthmus
 Commonly used in evolutionary studies to evaluate
morphological, ecological, and molecular divergences
 Rose ~3.1 MYA
 Vicariance hypothesis (Rosen)
 Dispersal hypothesis (Briggs)
 Ancestral species, Ophioblennius, separated 7 MYA
during initial shoaling
The Panama Isthmus
The Atlantic Redlipped Blenny
 Ophioblennius atlanticus & macclurei
The Pacific Fanged Blenny
 Ophioblennius steindachneri & clippertonensis
Question 2
 What are the different biogeographic regions and does
the presence of an oceanographic barrier (Panama
Isthmus) influence speciation of the blennies?
Pacific VS Atlantic Oceans
Pacific
Atlantic
 Reefs continuous along
 Reefs widely scattered
coastline
 Open ocean basin
 Unstable currents
 High rates of gene flow
 Closed ocean basin
 Stable currents
 Islands provided stepping
stones in range expansion
 Low 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.
Locations
Haplotypes
A study by Muss et al.
Conclusions
 O. atlanticus & O. steindachneri shared common
ancestor 7 MYA
 The 2 species of blenny were separated before
closure of the Panama Isthmus
 After 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 differentiation
 Populations closer to one another are more similar
Further Research
 Obtain 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
Sources
 Muss, 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.