Schaefer Lab

[Schaefer Lab Research] [USM Museum of Ichthyology] [Courses] [C.V.] [Other Links] 

Research

One of the greatest challenges in biology is to explain observed levels and patterns of species diversity. My research focuses on pieces of this puzzle on a variety of organizational levels from the physiology of individuals to the large scale temporal and spatial dynamics of assemblages. I use freshwater fishes as model organisms to address some of these problems. Much of my recent work has focused on fishes in the Fundulus notatus species complex. These species are ecologically and morphologically very similar and found throughout the Mississippi basin and Southern United States. The two most widely distributed members of this complex, F. notatus and F. olivaceus, occur throughout much of the Mississippi River drainage as well as the coastal drainages of the Gulf of Mexico. Throughout this range, the species encounter one another and hybridize in numerous contact zones. These contact zones are ecological and evolutionary replicates, making them an ideal study system for some basic questions:
  • Are contact zones structured along predictable ecological gradients?
  • Are the contact zones temporally stable?
  • What is the nature of the reproductive barriers among these species?
A third member of the F. notatus complex, F. euryzonus, is more narrowly distributed and endemic to the Pontchartrain drainage in Louisiana and southwestern Mississippi. This species is again ecologically and morphologically very similar, leading one to ask why its range is so limited in comparison to its sister species.
  • What factors explain the different distributional patterns observed broadly distributed and narrowly endemic sister species?
  • Are there physiological or life history differences that have limited the distribution of F. euryzonus?

Selected Recent Publications





Fundulus notatus, the blackstripe topminnow.


Three Fundulus olivaceus (identified via mtDNA haplotype) sampled from a contact zone. Note the variability in the spot phenotype.


Geographic ranges of fishes in the Fundulus notatus species complex.


USM Museum of Ichthyology

The USM Museum of Ichthyology is an invaluable resource for students and researchers interested in ichthyology. The museum currently contains more than 30,000 lots and 500,000 specimens representing over 700 taxa. While most of the collection contains fishes from the southeastern US, efforts are underway to add a number of unique collections from Honduras.

See the collection page for more deatils and for searching the database.

Quick Search by Species

Enter all or part of a family, genus or species name:


Enter all or part of a common name:



Current and Former Graudate Students