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.