entirely or isolated to the peaks. Quaternary no-analogs Quaternary fossil records from the Pleistocene present a developed history of no-analogs. Records of plants, mammals, coleopterans, mollusks and foraminifera with no modern analogs are abundant in the fossil record. In the last glacial maximum, species aggregations were different from previous time periods due to a unique set of climate conditions. The development of no-analog plant and mammal communities is often interconnected, and also tied to occurrence of no-analog climates. Changes in plant community compositions may also lead to no-analog conditions with addition of biotic pressures such as competition and disease, or enhanced fire regimes. The North American pollen record provides examples of detailed no-analog plant assemblages from the late quaternary. Pollen assemblages that contain no modern analog are present from many late glacial and early Holocene records, and extend from 14,000 to 12,000 years ago. Pollen is a commonly used proxy in studying plant no-analogs. These assemblages are marked by high abundances of taxa such as Betula, the co-occurrence of now allopatric species such as Fraxinus and Picea, and the low abundance of taxa that are now modernly abundant, such as Pinus. These associations are evident across Alaska, eastern North America, Europe and the southwestern US. The environmental conditions during the Pleistocene offered a climate that was more productive for plant species than climate conditions that exist today. This is evident through extensive records of high abundances of broadleaved trees Ulmus, Ostrya, Fraxinus and Quercus mixed with boreal conifers such as Picea and Larix during the late Holocene. New evidence states that deglacial temperatures are now hypothesized to be a major contributor to the formation of no-analog plant communities in the Midwestern US. Christensen bog fauna during this time period also represent a significant example of no-analog assemblages from the Pleistocene. It is also possible that these plant assemblages formed due to influence from megafaunal extinctions during the late quaternary, and there is also evidence that shows connection between novel plant assemblages and new fire regimes. Mammal no-analogs Pleistocene mammal assemblages had high levels of diversity and abundance of megafauna. During the late quaternary extinction there was a loss of many megafauna. This extinction has led to the creation of a no-analog for modern ecosystems, which are lacking high diversity or abundance of large herbivores. These no-analog mammal assemblages and the loss of megafauna coincides with no-analog plant community rise. The