The Use of Geological and Paleontological Evidence in Evaluating Plant Phylogeographic Hypotheses in the Northern Hemisphere Tertiary

A well-sampled phylogenetic analysis of the polystichoid ferns (Dryopteridaceae) suggests a complex biogeographical history involving both boreotropical migrations and recent transoceanic dispersals

“…Indeed, the Eocene-Oligocene divergence is consistent with the expansion (50-33 Ma) and then reduction (33-26 Ma) of boreotropical forest belt (Morley, 2003;Tiffney, 1985aTiffney, , 1985bWolfe, 1975). Ancestors of Phanerophlebia, Clade B and Clade C from the Old World, may have used different land bridges available in late Eocene-early Oligocene to colonize the New World (i.e., BLB and/or NALB; Manchester, 1999;Tiffney, 1985a;Tiffney and Manchester, 2001) (Table 4). This hypothesis is also congruent with the biogeographical history of Central American and Andean Polystichum proposed by Driscoll and Barrington (2007) as well as McHenry and Barrington (2014), who suggested that the Neotropical clade has a northern origin, and that the Andean Polystichum lineage originated from a boreotropical Mexican ancestor.…”

“…A warm climate, and existing land bridge connections (Bering Land Bridge [BLB] and North America Land Bridge [NALB]) generated a paratropical forest that spanned Eurasia and North America (Morley, 2003;Tiffney and Manchester, 2001;Tiffney, 1985aTiffney, , 1985bWolfe, 1975;Zachos et al, 2001). Cooling of the climate and tectonic movements during the early Oligocene led to the fragmentation of the boreotropical belt, and the migration of paratropical elements southward to tropical refuges, such as southwest China, Southeast Asia, Central America, and Mexico (Morley, 2003;Zachos et al, 2001).…”

Dispersals of Hyoscyameae and Mandragoreae (Solanaceae) from the New World to Eurasia in the early Miocene and their biogeographic diversification within Eurasia

“…However, these two landmasses separated from each other 100-120 million years ago (mya) (Bauer, 1993;Hay et al, 1999), and vicariance may be appropriate only to interpret the distributions of some anciently diverged plant taxa, such as Annonaceae and Alstroemeriaceae -Luzuriagaceae, that were dated to Cretaceous (Doyle et al, 2004;Vinnersten and Bremer, 2001). Many plant taxa disjunct between Eurasia and North America may represent elements of the once continuous Arcto-Tertiary or boreal floras in the Tertiary (Li, 1952;Tiffney, 1985;Tiffney and Manchester, 2001). Nevertheless, these disjunctions from the breakup of the once continuous Arcto-Tertiary or boreal floras may be restricted to the mid-Tertiary temperate elements (such as Anemone of Ranunculaceae and Viburnum of Caprifoliaceae) or early Tertiary tropical elements (such as Illiciaceae), which adapted to the climatic conditions in the high-latitude regions of the northern hemisphere (Tiffney and Manchester, 2001;Wen, 1999Wen, , 2001).…”

“…Many plant taxa disjunct between Eurasia and North America may represent elements of the once continuous Arcto-Tertiary or boreal floras in the Tertiary (Li, 1952;Tiffney, 1985;Tiffney and Manchester, 2001). Nevertheless, these disjunctions from the breakup of the once continuous Arcto-Tertiary or boreal floras may be restricted to the mid-Tertiary temperate elements (such as Anemone of Ranunculaceae and Viburnum of Caprifoliaceae) or early Tertiary tropical elements (such as Illiciaceae), which adapted to the climatic conditions in the high-latitude regions of the northern hemisphere (Tiffney and Manchester, 2001;Wen, 1999Wen, , 2001). For taxa with tropical affinities and/or younger than Miocene, the vicariance hypothesis may not be plausible.…”

“…It has been hypothesized that this distribution pattern among different Eurasian taxa could have been resulted from a common geologic or climatic event (Greuter, 1991;Jakob et al, 2007;Petit et al, 2003;Ribera and Blasco-Zumeta, 1998;Steward and Lister, 2001;Wu, 1988). Since the Cretaceous, the most remarkable physical changes of Eurasia were the retreat of Tethys Sea before Tertiary, the collision of the Indian Plate with Eurasia in early Tertiary followed by the uplift of the Himalayas and the aridification of Central Asia in the middle to late Tertiary, the connection and the breakup of Eurasia with North America through the Bering Land Bridge (BLB) and the North Atlantic Land Bridge (NALB) in the early to middle Tertiary, and the repeated advances/retreats of glaciers in the Quaternary (Barron and Peterson, 1989;Butler, 1995;Harrison et al, 1992;Lomolino et al, 2006;Tiffney and Manchester, 2001;Wen, 1999). However, the associations between the environmental changes and the distributions of plants throughout Eurasia have rarely been tested.…”