Interview with Dr Eugene Gaffney by Jan Matiaska, March 2005
Intro: Dr Eugene S. Gaffney studied at Rutgers - the State University of New Jersey (1961-1965; B.A. with honours) and Columbia University (1965-1969; Ph.D.). He commenced his professional employment at Columbia University as a teaching assistant (1965-1967), preceptor (1967-1969), and lecturer (1969-1970). In 1970, Dr Gaffney began his career at the Department of Vertebrate Paleontology of the American Museum of Natural History as an assistant curator, eventually becoming curator (1980-present). In 1980, he was a visiting curator at the Australian Museum in Sydney Australia. He has written or co-written more than 100 scientific papers. His contribution to the Chelidae taxonomy as well as the morphology of both fossil and living Australian chelids is enormous and that is why he is one of the Testudines highly esteemed authorities who deserve to participate in the interview series done by Carettochelys.com.
JM: Dr Gaffney, to be honest, I have never thought our site would host an interview with such an expert like yourself! I do feel privileged. I once said I considered your work out of this world! If it was not for you, we would know much less about the history of living Testudines, let alone the extinct ones. Anyway, Dr Gaffney, if I wanted to summarize your work in two simple words, I would say TURTLE FOSSILS. What was it that made you dedicate your life to the research of Testudines fossils?
GG: Turtles have an unusually good fossil record, and they are still living so its possible to determine with greater certainty homologous structures. Turtles allow systematic problems to be solved more easily than groups that either have no fossil record or are completely extinct. No one was working on them when I was ready for a thesis, and we have a lot of good skulls in the AMNH collection, fossil and recent, so it seemed like a good choice for the type of problems I was and still am interested in. Besides I started out interested in dinosaurs but my advisor, Colbert, wouldn't let me take the glass off the exhibits so my options were limited!
JM: In their 225 million years of existence, turtles have managed to survive conditions that extinguished the non-avian dinosaurs. They seem to be very adaptable, occupying various habitats ranging from bone dry deserts through tropical rain forests to water bodies including oceans. Their shell evolved at the very early stage of their history and probably served as one of the protection mechanisms against predators, but surely this factor on its own has not prevented the order from extinction. So what are, in your opinion, the main reasons to their survival abilities?
GG: I have no idea. They're really hard to kill though! Even tougher than cane toads. Maybe.
JM: You are known to have a very large turtle collection (if not the largest one in the US) in upstate New York. Many specimens of numerous species surely require a lot of maintenance. How do you manage to run the place and everybody including the turtles happy?
GG: Yes, my collection has grown steadily over many years! Species readily available in the 1960's and 1970's are still here! My caretaker situation varies greatly. There have been tough years where I have almost no help, and other years where I have up to 3 part-time young workers. The best years were when Patrick Baker was here, as his interests were the same as mine! Many filters have been used, but nothing works as good for me as total replacement of water at least weekly. I accept "pond-like" clean water, and do not try to keep artificially crystal-clear set-ups. Turtles like clean, but as natural as possible environments. It is a challenge to know when to clean, and when to not touch. Over time, a "keeper" with a "feel" for the turtles knows what each species requires.
JM: The Illustrated Glossary of Turtle Skull Nomenclature (1972), in which you presented the turtle skull terminology as standardized by Parsons and Williams (1961) including many figures, was a paper that helped me partially understand the turtle skull morphology. If it was not for this manuscript of yours, I would be lost among various synonymous and inconsistently used anatomical terms originating in numerous publications. This and many other papers you have written thorough the last 35 years clearly show your interest in turtle skull morphology. Why does this particular part of the turtle skeleton draw much of your attention? Has it got to do anything with your believe that the skull and neck are the two parts of turtle's skeleton that have gone through the most complex and extensive changes in the Testudines' history?
GG: Actually I use skull morphology because it simply has more characters and seems more susceptible to homology tests than the rest of the skeleton. I also use as many characters as I can from the whole skeleton, there just aren't as many. Many shell characters also show too much individual variation.
JM: As you probably know, our web page is dedicated to the Australasian families Chelidae and Carettochelyidae which are members of Pleurodira and Cryptodira infraorders respectively. It is believed the members of both infraorders developed different biomechanical strategies of redrawing their heads long after Pleurodires diverged from Cryptodires. What factors could have possibly affected the two turtle lineages in adopting these two different techniques (horizontal vs. vertical) which serve the same purpose and which one of them is more primitive?
GG: Again I have no idea, I'm not into the speculative aspect of evolution. Impossible to test. I suspect it was an evolutionary accident with no real adaptive significance, but this is just an idle guess. Chelids show a good vicariant pattern, but the remaining Pleurodires are very old and show a complex biogeography. I've never been too interested in evolutionary scenarios, they are not very satisfying. It's hard enough to deal with stuff that you can handle more or less objectively.
JM: Over the last few decades there has been a major paradigm shift in biology and systematics, with the evolutionary systematics (Linnean system) being replaced by the cladistics (phylogenetic systematics). You were one of the first ones to adopt this new methodology to determine evolutionary relationships. As we both know, the cladistics can be somewhat tricky when dealing with fossils because it disregards the sequence of fossils in the stratigraphic record. Despite this fact, your cladograms do not contain any "hidden lineages" - a standard result of a cladogram that does not agree with the fossil record for a particular group. How do you tackle this issue?
GG: Cladistics has been around for a long time, people at the AMNH were doing it in 1965 so the methodology has been the norm for a couple of generations. I first got interested in cladistics about 1966 because people around me were doing it. I was only the first to do it on turtles, but that was also a function of very few turtle systematists of any kind at that time. Turtles were ripe for any thorough systematics when I was a graduate student. Cladistics is not tricky for fossils; they do usually have more missing data but otherwise are the same as a recent taxon in an analysis. A "hidden" lineage as I understand the term would include some of my cladograms, although I do not think cladograms have lineages represented in them. But if you do change a cladogram into an evolutionary tree with lineages, then something like the pre-Jurassic Cryptodires would be a hidden lineage, so one could interpret my cladograms as having these.
JM: The Pleurodira infraorder was widespread in the Cretaceous and Tertiary, but nowadays the living members of this infraorder are found in the southern hemisphere only and contain much less genera then the Cryptodira infraorder. What were the main reasons for many Pleurodira species (for example of the Bothremydidae family) going extinct during the last 2 million years?
GG: Again I have no idea. Although the big Pleurodire die-off seems to have been the Eocene-Oligocene boundary. Generally, Pleurodires seemed perfectly well able to manage north or south. Another of those pesky evolutionary accidents I'll bet! But who knows.
JM: Lord Howe Island, a small island in the South Pacific, revealed the fossils of the Giant Horned Turtle - Meiolania platyceps (Cryptodira), which died out about 100,000 years ago. You have personally studied the fossils of this strange turtle and its close relatives (other species of the Meiolania genus as well as other genera including Warkalania, Ninjemys, and Niolamia). All members of the Meiolaniid family had horns on their skulls, but despite this synapomorphy, they greatly varied in size (of both the skull itself and the horns) and shape. Do any of Meiolaniid fossils suggest some species were sympatric and if so, which ones?
GG: Sympatric Meiolaniids. Well, Ninjemys and that giant cf. Meiolania platyceps I described are both from the Plestocene of Queensland, not the same spot and dating isn't precise enough to tell, but they could have been sympatric. Hard to tell.
JM: Your theory of the presence of these terrestrial turtles on oceanic islands says it was probably the result of relic populations remaining on volcanic islands when continental crust has foundered. Have you considered any other theories - other possible means of the widespread distribution of the Horned Turtle on these islands?
GG: Sure. But I'm afraid my limited biogeography is of the vicariance variety and this is the most parsimonious explanation. Meiolaniids also fit the pattern shown by some other Oceanic groups on the Lord Howe Rise: palms, some insects, etc. The only reason I studied these crazy things was to get to Lord Howe Island every year or so…… It's somewhat cooler than the Simpson Desert in December.
JM: Dr Gaffney, you have done fieldwork in Canada and the United States, central Europe, southern Africa, China, Argentina, Brazil, and Australia, where you also spent some time as a visiting curator at the Australian Museum, Sydney. You studied both living and fossil specimens of the Chelidae family belonging to the Emydura, Chelodina and Pseudemydura genera. The taxonomy of these extant forms of the Australian chelid turtles is still not well defined. Meanwhile, other genera, Elseya latisternum group, Elseya dentata group, Rheodytes, Elusor, Birlimarr, Macrochelodina, have been either erected or accepted and brought more complexity to the Australasian Chelidae taxonomy. Are you planning on participating in resolving this taxonomic puzzle?
GG: Actually it's the Cretaceous chelids now known from skulls that are more likely to affect morphologic character-based cladograms. Once they become better known it will be more interesting. The differences I have with the sequencing-based cladograms are primarily with the genus Chelodina, the rest of the analyses pretty much agree.
JM: Every once in a while some deposits yield new turtle fossils. Each new finding can help us broaden our knowledge of these peculiar creatures including their phylogeny. I am sure you will actively get involved in further turtle fossil research, but are there any particular areas which you would like to focus on?
GG: Yes, Lord Howe Island, a stubby on the beach is my main focus. However, I usually do taxa rather than geography and now that the basal Pelomedusoide and Bothremydids are finished, I'm trying to make more progress on the Podocnemidids. All of these have interesting distribution patterns.
JM: Dr Gaffney, thank you very much for answering my questions! I wish you all the best (and a lot of well-preserved fossil specimens).
To view the research interests of Dr Gaffney, please visit research.amnh.org/users/esg/
2005-03-22 / Copyright © 2005 Jan Matiaska.
All rights reserved