W. Brian Simison, Ph.D.

W. Brian Simison, Ph.D.
Nothing in Biology Makes Sense Except in the Light of Evolution
—Theodosius Dobzhansky
"Biology, Molecular and Organismic", American Zoologist.

My research focus is on the global phylogeography of limpets (Gastropoda: Patellogastropoda). My colleagues and I are examining the evolution and systematics of limpets and the mechanisms of vicariance, dispersal and speciation.

Antitropical distributions

We are investigating the processes that lead to antitropical distributions (taxa found in both the northern and southern temperate regions, but not in the intervening tropical region). Many marine and terrestrial organisms are distributed above and below the tropics including limpets.


Seagrass Limpets

Seagrass limpets have an unusual distribution compared to the rest of the temperate northeast Pacific limpets; they are restricted to the southernmost region of the northeast Pacific temperate waters. This group of specialized limpets lives exclusively on the seagrasses Phylospadix and Zostera and they are the only cold water limpets that are members of the tropical New World clade of limpets. The last known tropical New World seagrass limpet has been extinct for 5 million years.


Extinct Limpet?

We are actively searching for natural populations of the very rare Mexican limpet (Scutellastra mexicana). This is the largest species of limpet ever known (180cm) and unfortunately, it has been collected to near extinction as a delicacy ingredient in ceviche. We hope to publicize the fate of this endangered animal and have it added to the CITES species database.


Mitochondrial Evolution

We are attempting to uncover the mechanisms of mitochondrial DNA strand bias, gene order variation and the associated consequences that these phenomenon have on phylogenetic analyses.


Curriculum Vitae & Publications

Simison Curriculum Vitae.
Simison Publications.

About the Department

General information and a brief history of molecular systematics at the California Academy of Sciences

CCG Personnel


Staff, students, researchers & associates.

Osher Lab


Information about our sequencing facilities & how to gain access to the labs. Lab protocols and policies can also be found here.



Information about the Computing Cluster & how to access it.



Learn about our collection of frozen genomic DNA.

Contact Info


For general inquiries about the CCG please contact:

Brian Simison Ph.D.

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