Senior Research Assistant
Department of Biology
Campus Box 1137
Washington University in St. Louis
St. Louis, MO 63130-4899
email: knicholson@biology2.wustl.edu
Phone: 314-935-7256
Fax: 314-935-4432
Research Interests:
I am an evolutionary biologist interested in the phylogenetic relationships of reptiles and amphibians, phylogenetic and comparative evolutionary methodologies, as well as the general biology/ecology/natural history of reptiles and amphibians. My research has revolved around a group of lizards in the genus Anolis and has several foci: to reconstruct the evolutionary relationships among the species, to test biogeographic hypotheses involving anoles, to describe and explain the immense diversity among Anolis dewlaps, and to fill in gaps in our general knowledge of anoles. For such a well-studied group to date, there is in fact very little known about most species of anoles.
Full CV
Field Trips
Links
Education:
2001 Ph.D., Biology; University of Miami, Florida.
1995 M.S., Zoology; Auburn University, Alabama.
1991 B.S., Biology/Vertebrate Zoology; University of Memphis, Tennessee.
Funding:
1999 $500 Gaige Award (Association for the Study of Ichthyology and Herpetology).
1999 $10,000 National Science Foundation Dissertation Improvement Grant.
1998 $300 Graduate Association Funds Allocation Committee, University of Miami.
1998 $300 Graduate Research Award, University of Miami.
1997-1998 $12,000 Tropical Biology Fellowship, University of Miami.
1994 $1,500 Pilot Award Grant from the Organization of Tropical Studies
Publications
Nicholson, K.E., R.E. Glor, J.J. Kolbe, A. Larson, S. Blair Hedges, and J.B. Losos. 2004. Mainland colonization by island lizards. Journal of Biogeography (in press).
Gutsche, A., J.R. McCranie, and K.E. Nicholson. 2004. Field observations on the natural history of Norops utilensis Köhler 1996 (Reptilia, Squamata) with comments about its conservation status. Salamandra (in press).
Nicholson, K.E. 2004. Historical biogeographic relationships within the tropical lizard genus Norops. Chapter 14 in Ecology and Evolution in the Tropics: essays in honor of Jay M. Savage. Donnelley et al., eds. University of Chicago Press (in press).
Köhler, G., J.R. McCranie, K.E. Nicholson, and J. Kreutz. 2003. Geographic variation in hemipenis morphology in Norops humilis (Peters), and the status of N. quaggulus (Cope) (Squamata: Polychrotidae). Senckenbergiana Biologica 82:213-222.
McCranie, J.R., F.E. Castañeda, and K.E. Nicholson. 2002. Preliminary results of herpetofaunal survey work in the Rus Rus region, Honduras: a proposed biological reserve. British Herpetological Society Bulletin 81:22-29.
McCranie, J.R., K.E. Nicholson, and F.E. Casteñeda. 2002. Eleutherodactylus diastema. Herpetological Review 33:220.
Nicholson, K.E. 2002. Phylogenetic analysis and a test of the current infrageneric classification of Norops (beta Anolis). Herpetological Monographs 16:93-120.
McCranie, J.R., K.E. Nicholson, and G. Köhler. 2001. A new species of Norops (Sauria: Polychrotidae) from northwestern Honduras. Amphibia-Reptilia 22(4):465-473.
Gillespie, T. K.E. Nicholson, and J. McCrary. 2001. Patterns of diversity and conservation in Nicaragua. Natural Areas Journal 21:159-167.
Nicholson, K.E., R. Ibañez, C Jaramillo, and K.R. Lips. 2001. Geographic variation and brief natural history notes in the tropical anole, Anolis casildae (Squamata: Polychrotidae). Revista Biologia Tropical 49(2):709-714.
Köhler, G., J.R. McCranie, and K.E. Nicholson. 2000. Eine herpetologische expedition in den Patuca-Nationalpark, Honduras. Natur und Museum 130(12):421-425.
Nicholson, K.E., J.R. McCranie, and G. Köhler. 2000. Herpetofaunal expedition to Parque Nacional Patuca: a newly established park in Honduras. British Herpetological Society Bulletin 72:26-31.
Nicholson, K.E., A.V. Paterson, and P.M. Richards. 2000. Anolis sagrei Cannibalism. Herpetological Review 31(3):173.
Nicholson, K.E. 1999. Phylogenetic analysis of Norops (Beta Anolis) species: preliminary data. Anolis Newsletter V:89-94.
Nicholson, K.E. and P.M. Richards. 1999. Observations of a population of Cuban Knight Anoles, Anolis equestris. Anolis Newsletter V:95-98.
Nicholson, K.E. 1999. Anolis casildae Foraging. Herpetological Review 30:96.
Nicholson, K.E. 1998. Enyalioides heterolepis. Herpetological Review 29:174.
Nicholson, K.E. and D.T. Nicolson. 1997. Norops pachypus. Herpetological Review 28:96-97.
Guyer, C., K.E. Nicholson and S. Baucom. 1996. Effects of tracked vehicles on gopher tortoises (Gopherus polyphemus) at Fort Benning Military Installation, Georgia. Georgia Journal of Science 54:195-203.
Weckerly, F.W., K.E. Nicholson, and R.D. Semlitsch. 1989. Experimental test of discrimination by squirrels for insect infested and noninfested acorns. American Midland Naturalist 122:412-415.
Projects/Publications In Progress (annotated list)
Barros, T.R., L.F. Esqueda, A. Mijares-Urrutia, and K.E. Nicholson. The lost link rediscovered: variation and distribution of Norops annectens (Squamata: Polychrotidae). In review, Herpetologica.
On a recent trip to Venezuela we rediscovered A. annectens. Williams (1974) described thiS species on the basis of a single museum specimen and declared it the missing link between the genera Anolis and Tropidodactylus (which was later synonymized with Anolis). This species has never been seen live until our discovery in Sept. 2003. We found 16 specimens over a broad range and thus report on the distribution, morphological variation, and behavior of this elusive anole.
Nicholson, K.E., A. Larson, and J.B. Losos. Evolution of dewlap morphology in Caribbean Anolis lizards. In prep.
We investigate the morphological diversity and evolution of anole dewlaps in this paper. We first characterize dewlap morphological diversity and propose terminology to describe the 9 patterns exhibited, then test three hypotheses previously proposed to explain the diversity of dewlaps found in the Caribbean. We find no support for any single hypothesis, but find that all three may have played a role in driving selection for size, color and patterning among dewlaps of different species.
Nicholson, K.E., A. Mijares-Urrutia , L. Harmon, and J.B.Losos. Molecular support for the retrograde evolution hypothesis. In prep.
We provide molecular data for several poorly known anole species showing support for the retrograde evolution hypothesis of Williams (1976) where unique anoles have lost the usual toe condition and lack lamellae concomitant with a terrestrial lifestyle .
Nicholson, K.E., and P.M. Richards. Divergent ecology and natural history of the giant canopy anole, Anolis equestris. In prep.
This paper investigated the ecology and biology of a canopy anole, a poorly studied ecological group of lizards. Our data show that home range patterns of this species are very different from other anoles studied to date, and suggests that the behavioral and reproductive ecology of this species is quite divergent from more terrestrial anoles that are better studied to date. .
Paterson, AV. and K.E. Nicholson. The effects of tail autotomy on territory establishment by brown anoles (Anolis sagrei). In prep.
We conducted experiments to investigate the effects of tail breakage on territoriality in Anolis sagrei males. We found that tail loss had no effect on territory establishment among males that were size matched, contrary to what other publications had suggested. .
Nicholson, K.E., S. Poe, and K. de Queiroz. A re-evaluation of Anolis taxonomy and test application of PHYLOCODE. In prep.
We are in progress writing up the synonymies for all valid anole names and analyzing all currently published data to generate the best phylogenetic hypothesis of relationships among anoles. With these data we will apply the new PHYLOCODE rules as a test case for revamping the currently very messy classification of anoles.
Anolis (in brief)
This genus of lizards has received enormous attention from biologists of nearly every flavor and the group has served as model organisms for a variety of studies (search "Anolis" using any search engine or database and you'll pull up thousands of studies). They are fascinating in nearly every way, and particularly evolutionarily. They occur in the southwestern United States, throughout the West Indies, and tropical Central and South America. Currently there are about 354 species (although this is another topic of research of mine), approximately half of which are West Indian, the other half mainland. They vary in every way possible morphologically: size, shape, coloration, scalation, you name it. They also differ behaviorally, physiologically, and most famously, ecologically. The Caribbean anoles are the best studied to date and research from the Losos lab at Washington University in St. Louis has shown that the suite of ecomorphs on each of the Greater Antillean islands have evolved independently, making them the first known case of repeated evolution.
Evolutionary Relationships
The phylogenetic relationships of Anolis species have been difficult to unravel, but major advances been made recently towards elucidating these relationships. Richard Etheridge (1960) and Ernest Williams (1976a, b) together developed hypotheses of relationship among anoles and over several decades Williams continued to refine these ideas into an elaborate (?dizzying?) hierarchical arrangement. Many workers in the field have added to these ideas, most of whom were working on smaller groups of anoles. However, the work of many people using various types of data resulted in a confusing array of alternative phylogenies. During the last decade, however, huge molecular datasets have been collected and compiled (by several workers including myself), and an enormous amount of morphological data has been collected by Steve Poe (vastly extending the pioneering work of Etheridge). These datasets independently and combined have advanced our knowledge of Anolis relationships and can perhaps be summarized as follows:
* Etheridge and Williams' hypotheses of relationship
for Caribbean anoles were pretty dead on (with some
exceptions), while they seem to have gotten most of
them wrong for mainland anoles.
* Lower level hypotheses such as for species groups
were sometimes upheld by molecular data for some
mainland groups.
* There appears to be a startling amount of
morphological convergence among anoles, particularly
among Caribbean species, which has resulted in part in the
now famous ecomorphs of the Greater Antilles.
Biogeographic Hypotheses
Anolis lizards have also figured prominently in biogeographic debates regarding the origin of Caribbean fauna and vicariance versus dispersal explanations for their existence on the islands. Several alternative explanations have been proposed to explain the current distributions of Anolis based upon various data. My work has in this realm has largely involved teasing apart various hypotheses that attempt to explain the origin of one clade of anoles, the "Norops" clade (or beta section of Anolis). The prevailing paradigm had been that Norops originated on the mainland (perhaps Mexico) and later dispersed southerwards through Central America and into South America. At some point anole propagules were believed to have dispersed over water to Cuba and Jamaica. Our latest work suggest that this is not the case, and that Norops originated in the Caribbean (perhaps on some part of Cuba) and later dispersed overwater to the mainland (and also to Jamaica). This scenario not only bucks the prevailing paradigm, but also suggests that a single invading ancestor gave rise to the mainland anole radiation, which is roughly equal in size to the Caribbean radiation.
Dewlaps
One of the most exciting features of Anolis lizards are their dewlaps, a structure below their chins that forms part of their communication reportoire. As some of the adjacent slides show, they vary in every way (shape, size, color, pattern). The literature would seem to suggest that there is so much variability in dewlap morphology that they are akin to snowflakes: no two are alike. My work describing the variation in dewlaps shows that indeed, while there are many
patterns shared by Caribbean species, in fact very few species have identical
dewlap morphologies. While several explanations have been forwarded to explain this variation (such as sexual selection, species recognition, communication effectiveness), my analyses suggest that none of these explanations are supported by the data. Perhaps all of these pressures have been operating simultaneously, but teasing that apart has proven difficult.