Evolutionary Studies of Blind White Cavefish

In 1955, my Cornell undergraduate advisor loaned me Carl Engelmann’s 1909 Blind Vertebrates of North America.  It included microscopic eye anatomy of all the swamp, spring, and cave species in the fish family Amblyopsidae.  I read it cover to cover in one day.  I immediately decided that I wanted to study all aspects of the evolutionary adaptation of the family for my Doctoral Dissertation at University of Michigan – Ann Arbor.

Based on the evolutionary trends, I documented, for the three known obligate cave Amblyopsids I predicted in my 1961 Dissertation, what an even more cave-adapted species would look like and why.  Sometime in the late ’60s, I received an anonymous letter with a photo of a white cavefish.  The only writing was,”Is this what you predicted?”  It was!  I figured out who my compatriots were and helped them study preserved specimens.  In 1974, they published a formal description of this new species in peer-reviewed literature.  They named it Speoplatyrhinus poulsoni in my honor!

Speoplatyrhinus poulsoni

But the very best was yet to come.  After years of trying to arrange a visit to its only habitat, Key Cave, I finally got to see my namesake up close and personal.  On Election Day 2008, a colleague snorkeled to net a fish and passed it to me in a plastic bag.  I whooped, clapped, hollered, and stamped in excitement and glee!  We took three specimens just outside the cave where I studied them in an aquarium and Dr. Dante Fenolio photographed them in his special mini aquarium.  Then we returned them to the cave.  Attached is Dante’s image of a 65mm adult.  Note its relatively huge head and ridges of water-motion detecting sense organs.

By yet another serendipity, FAU Jupiter has hired Dr. Alex Keene, who uses state-of-the-art molecular and neurophysiological methods to study Mexican cavefish.  He and his graduate students and I have had several meetings to decide which of his methods would provide the greatest new insights into the evolution of Amblyopsid cavefish.  I am really excited that this March we will start studies of sleep that will complement my original studies of circadian rhythms and activity levels.

Dr. Tom Poulson

Tom Poulson, Ph.D., taught at Yale, Notre Dame and the University of Illinois – Chicago. He uses his award-winning style of interactive teaching which includes voting, demonstrations, doggerel and cartoons. Past LLS students speak of his unbridled and contagious enthusiasm, stimulation of thought and imagination and integration of humor with science.

It's only fair to share...
000