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John R. Holsinger and David C. Culver 
incompatible with an origin in the higher mountains on the eastern side 
of the Appalachian Valley. 
The presence of vestigial eyes in some species of Pseudanophthalmus 
viz., members of the petrunkevitchi group and P. vicarius ) suggests a 
fairly recent invasion of caves by some species (Barr 1965) if the degree 
of eye reduction is a crude measure of the length of time a species has 
lived in a cave. On the other hand, the level of intrageneric diversity and 
the occurrence of many distinct species groups suggest the possibility 
that Pseudanophthalmus is much older than the Pleistocene (see Barr 
1981a). Given this background, one might postulate that the colonization 
of caves by species of Pseudanophthalmus has taken place over a long 
period of time through a succession of independent invasions. The 
occurrence of many distinct species groups, some of which broadly 
overlap geographically in southwestern Virginia and eastern Tennessee, 
suggests several independent colonizations of caves by ancestral stocks. 
How closely these colonizations might have coincided with the beginning 
of Pleistocene interglacials is difficult to determine, however. 
The presence of P. sylvaticus in a non-cave habitat is of zoogeo- 
graphic interest because this species is the only non-troglobitic 
Pseudanophthalmus recorded from North America. Barr (1967c, 1969) 
believes it is probably a periglacial relict that survived in the ecologically 
suitable habitat of a cold mountain forest during one of the interglacials 
when many of its congeners either were extirpated on the surface by a 
progressively warmer and drier climate or survived by colonizing caves 
at low elevations. Pseudanophthalmus sylvaticus was collected and 
described by Barr (1967c) from an endogean habitat in the Yew 
Mountains, approximately 36 km west of the study area on the eastern 
margin of the Appalachian Plateau in Pocahontas County, W.Va. This 
species, which has rudimentation of both eyes and pigment, is an 
edaphobite, presumably closely similar to putative preadapted ancestors 
of troglobitic members of the genus. It is not far removed taxonomically 
from some of the present cave forms living in limestone areas just to the 
east. 
Although Barr (1967c) suggested that the discovery of P. sylvaticus 
supports the Pleistocene climatic-effect theory, we believe that it could 
also support Howarth’s adaptive-shift theory. For example, if preadapted 
species of Pseudanophthalmus colonized caves in response to newly 
opened niches, it is unlikely that all members of the genus would have 
gone underground. Those left behind on the surface could have persisted 
in ecologically suitable habitats like that of P. sylvaticus in the Yew 
Mountains. In reality, neither hypothesis is falsified by the discovery of 
P. sylvaticus , since both predict the occurrence of preadapted epigean 
congeners in groups with troglobitic species. 
