150 Joshua Laerm 



and no karyological differences; based on mitochondrial DNA sequence 

 relatedness, they share a common lineage. Second, based on archaeolog- 

 ical evidence it is believed that Cumberland Island was connected to 

 mainland Georgia as recently as 5000-7000 years Before Present (R. 

 Frey, pers. comm.). 



Most species and subspecies groups of Recent mammals are, at the 

 youngest, of Pleistocene origin (Hibbard et al. 1965). Russel (1968) sug- 

 gested that G. pinetis differentiated from Geomys bursahus by the Sang- 

 amon, and G. pinetis is recorded from Irvingtonian to Recent deposits 

 in Florida (Webb 1974). Isolation of a population of pocket gophers on 

 Cumberland Island for 5000-7000 years would, in general, be recognized 

 as too short a period for speciation. 



I conclude that the most parsimonious interpretation consistent 

 with available data is that G. cumberlandius cannot be shown to be 

 distinct from mainland populations of G. pinetis. I therefore agree with 

 the conclusions of Williams and Genoways (1980) that pocket gophers 

 on Cumberland Island be synonymized with adjacent mainland G. pine- 

 tis. 



ACKNOWLEDGMENTS.— I wish to thank the curatorial staff of 

 the American Museum of Natural History (ANMH), Carnegie Museum 

 of Natural History (CMNH), Cornell University Museum (CU), Dela- 

 ware Museum of Natural History (DMNH), Florida State Museum 

 (FSM), Museum of Comparative Zoology (MCZ), and U.S. National 

 Museum of Natural History (NMNH) for access to their respective col- 

 lections. Additional specimens from the University of Georgia Museum 

 of Natural History (UGAMNH) were included in this study. The coop- 

 eration of Ron Odom of the Georgia Department of Natural Resources 

 is much appreciated, as was the statistical advice of T. Richardson. This 

 work was financed largely by grant-in-aid funds under Section 6 of the 

 Endangered Species Act of 1973, the Theodore Roosevelt Fund of the 

 American Museum, and the Department of Zoology, University of 

 Georgia. This is a contribution of the University of Georgia Museum of 

 Natural History. 



LITERATURE CITED 

 Albrecht, Gene H. 1978. Some comments on the use of ratios. Syst. Zool. 



27:67-71. 

 Atchley, William R., and D. Anderson. 1978. Ratios and statistical analysis of 



biological data. Syst. Zool. 27:71-78. 

 C. T. Gaskins and D. Anderson. 1976. Statistical properties of ratios. 



I. Empirical results. Syst. Zool. 25:137-148. 

 Avise, John C, C. Giblin-Davidson, J. Laerm, J. C. Patton and R. A. Lans- 



man. 1979. Mitochondrial DNA clones and matriarchal phylogeny within 



and among geographic populations of the pocket gopher, Geomys pinetis. 



Proc. Natl. Acad. Sci. U.S.A. 7(5:6694-6698. 



