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[December 
dispersal, of which winged Adelopsis (and Ptomaphagus) should 
have been capable. 
These considerations then suggest an origin of Adelopsis in 
“tropical” North or Central America perhaps in the late Cretaceous 
or early Tertiary, and a movement through forests in the early 
Tertiary into the Appalachian Region. The continuous distribution 
of the genus was then broken with the developing xeric climates of 
the Miocene, forming an effective non-forested barrier across what 
is now northern Mexico (Axelrod, 1960, Graham, 1973). This 
disjunction is observed in many groups (see Rosen, 1978). Since this 
disjunction the assumed large-eyed and winged ancestral stocks 
have vanished from what became the United States, leaving only the 
small-eyed and wingless soil species of the Appalachians. Past 
workers have suggested that the mesic forests of the Appalachians 
and Mexico were rejoined in Pleistocene glacials, but most recent 
analyses do not tend to support this (Graham, 1973; Martin and 
Harrell, 1957; Rosen, 1978). 
The comparative uniformity of overall morphology and aedeagal 
types in the Appalachian species suggests that a single ancestral 
species became an inhabitant of soil and deep litter. Subsequent 
(late Tertiary?) isolations perhaps produced the set of less-similar 
species in the mitchellensis species group. Differentiation of these 
species may have been reinforced by Pleistocene climatic fluctua- 
tions and distributional displacements. One of these species may 
have become something like A. appalachiana and it experienced 
speciation by range expansion, contraction, and population isola- 
tion in response to Pleistocene climatic fluctuations. The more cool 
and wet conditions accompanying glacials (Watts, 1970, 1975; 
Whitehead, 1965) would allow their spread through the lowlands. 
Warmer and drier conditions of interglacials would separate popu- 
lations of these seemingly poorly mobile beetles as they retreated to 
favorable and more isolated sites at higher elevations or in mesic 
forest refugia of canyons, gorges, and protected spots below topo- 
graphic escarpments. By this process, an A. appalachiana-\\ke 
ancestor differentiated into the species of this more closely knit 
group. 
The production of 16 species from one ancestor seems only a 
modest amount of differentiation if the southeastern Adelopsis have 
truly been isolated from their Neotropical congeners for some 35-40 
million years, especially when compared to some examples of 
