The Troublesome Formation of northcentral Colorado ranges in age from the middle Arikareean North American Land Mammal Age (NALMA: latest Oligocene) to the early Clarendonian NALMA (early–late Miocene), a range of 14.5 million years. The rodent fauna from this formation varies greatly through the section, which is dominated by entoptychine geomyids in the Arikareean, mylagaulids in the Hemingfordian, and heteormyids in the Barstovian. The Clarendonian is the least-well represented horizon from which only four species are recognized. Of the nearly forty species of rodents identified, there is only one new genus, Argaleogaulus a primitive promylagauline mylagaulid from the Arikareean. There are 12 new species recognized: the mylagaulid Argaleogaulus primoticus; a sciurid, Protospermophilus parvus; six heteromyids, Harrymys cyanothos, Harrymys taussigi, Schizodontomys bareia, Balantiomys coloradensis, Oregonomys perilaccos, and Cupidinimus robinsoni; and four entoptychine geomyids, Pleurolicus compressus, Pleurolicus mensae, Gregorymys montanus, and Entoptychus rensbergeri. The genera from the Troublesome Formation are similar to those of equivalent faunas throughout North America. The presence of the unique species of otherwise common North American genera suggests some minor degree of isolation of the basin during the time of formation.

Multi-year studies of syntopic species provide a spatiotemporal framework for comparing their demographic responses to the same environmental conditions. We used data derived from 15 years of sampling at an artificial pond matrix in southwestern Pennsylvania to investigate the survival, growth, and ages of Midland Painted Turtles (Chrysemys picta marginata) and Common Snapping Turtles (Chelydra serpentina serpentina). We trapped turtles with baited hoop-nets at a primary wetland, which was the largest and deepest of five artificial ponds in a spatially aggregated matrix at the Powdermill Nature Reserve, a protected site in the Allegheny Mountains. We captured 81 Midland Painted Turtles 162 times, and 43 Common Snapping Turtles 136 times. For both species, apparent survival probabilities were higher for adults (range 79–95%) compared to juveniles (range 57–82%), and higher in females compared to males or juveniles. The average growth rate was highest in juvenile turtles of both species, indicating growth was maximal during periods of the lowest survival. Average growth rates, in general, were slower for Midland Painted Turtles compared to Common Snapping Turtles. Relating body size to age revealed estimates conforming to studies elsewhere and to longevity records based on known-age turtles. We interpret findings at this wetland matrix to represent the demographics of a deme within a fluid and dynamic regional network of demes for these two species and highlight the value of artificial pond networks to the conservation of freshwater turtle metapopulations in Pennsylvania.