Status of Geomys cumberlandius 



149 



q 



T 

 60 



100 



80 



40 



T 

 20 



& 



80 



60 



T" 

 40 



20 



100 







Fig. 2. Distance phenogram for males (A) and females (B). Generalized squared 

 Euclidean distances derived from Discriminant Function Analysis of raw data. 

 Ordinate numbers refer to population locations given in Figure 1; abscissa 

 numbers are generalized squared distances. 



The very large size of Cumberland Island gophers in comparison to 

 mainland forms was the chief criterion for Bangs' recognition of G. 

 cumberlandius. The data in Table 2 support his observation only in 

 part, because only total length of males is seen to differ significantly in 

 comparison to other populations. However, significant size difference 

 between mainland and insular populations of the same species is not an 

 uncommon phenomenon in vertebrates, particularly mammals (see Case 

 1978; Heaney 1978). While insular populations of rodents and other 

 small mammals are generally larger than mainland forms, the insular 

 populations are rarely regarded as representing distinct taxa. The large 

 body size of Cumberland Island gophers is consistent with this general 

 observation in other small mammals. Thus, body size alone would not 

 be strong support for species level recognition for Cumberland Island 

 pocket gophers. 



Other indirect evidence also argues against such recognition. First, 

 Avise et al. (1979) and Laerm et al. (in press) have shown that popula- 

 tions of pocket gophers throughout eastern Georgia and northeastern 

 Florida show no detectable protein heterozygosity for 25 loci examined, 



