Dinosaur biogeographical structure and Mesozoic continental fragmentation: a network‐based approach

Abstract

Aim To reconstruct dinosaur macro‐biogeographical patterns through the Mesozoic Era using a network‐based approach. We test how continental fragmentation affected dinosaur macro‐biogeographical structure and evolutionary rates. Location A global occurrence database of dinosaur families from the Late Triassic to the end‐Cretaceous was used for this study. Methods Biogeographical and geographical network models were constructed. Continental landmasses were linked by direct continental contact and sea level (SL)‐conditioned connections in geographical networks, and by shared dinosaur families in biogeographical networks. Biogeographical networks were run with raw, novel and first‐step connections for all dinosaur, ornithischian, theropod, and sauropodomorph taxa. Results Geographical connectedness declines through time, from peak aggregation in the Triassic–Jurassic to complete separation in the latest Cretaceous. Biogeographical connectedness shows no common trend in the raw and novel connection network models, but decreases through time while showing some correlation with continental fragmentation in most of the first‐step network models. Despite continental isolation and high SLs, intercontinental faunal exchange continued right up to the end of the Cretaceous. Continental fragmentation and dinosaurian macro‐biogeographical structure do not share a common pattern with dinosaurian evolutionary rates, although there is evidence that increased continental isolation resulted in increased origination rates in some dinosaurian lineages. Spatiotemporal sampling biases and early Mesozoic establishment of family‐level distribution patterns are important drivers of apparent dinosaur macro‐biogeographical structure. Main conclusions There is some evidence to suggest that dinosaur macro‐biogeographical structure was influenced by continental fragmentation, although intercontinental exchange of dinosaur faunas appears to have continued up to the end of the Cretaceous. Macro‐biogeographical patterns are obscured by uneven geographical sampling through time and a residual earlier Mesozoic distribution which is sustained up to the end of the Cretaceous.

Palaeoenvironmental drivers of vertebrate community composition in the Belly River Group (Campanian) of Alberta, Canada, with implications for dinosaur biogeography

“…The sensitivity of dinosaur populations to changes in altitudinal (distance from palaeoshoreline) and latitudinal environmental gradients has been the subject of considerable debate for over 30 years [1–9, 11, 15, 23, 26, 27, 42–46, 55, 62, 70], and though it has been questioned [17, 18, 22, 28, 74], it remains one of the primary explanations for patterns observed in the evolution and distribution of dinosaurs throughout the Late Cretaceous of western North America. A focused sub-sampling of the time-equivalent interval of the Oldman and Dinosaur Park formations within the larger Belly River Group microsite abundance dataset facilitates a controlled and direct test of dinosaur assemblage changes across differing palaeoenvironments (Figs.…”

“…Environmental changes caused by transgression-regression cycles of the Western Interior Sea have been suggested to drive the high diversity and high faunal turnover rates of non-avian dinosaurs [4, 5, 8–11], along with changes in the vertebrate community structure more generally [12–16]. However, global-scale analyses of dinosaurs, as a whole [17] and at the family level [18], indicate that large-scale changes in sea level may not have had a significant influence on broad patterns of diversity, evolution, or migration. This suggests that putative patterns in dinosaur ecology and evolution related to sea level, such as those described from Western North America, may be either the result of other factors, such as sampling biases, or may be occurring on a scale that is too small to be readily detected in such coarse-scale analyses [4].…”

The tracks of giant theropods (Jurabrontes curtedulensisichnogen. & ichnosp. nov.) from the Late Jurassic of NW Switzerland: palaeoecological & palaeogeographical implications

“…Accordingly, giant theropod tracks may have some significance for dinosaur biogeographic structure and continental fragmentation (see also Dunhill et al 2016).…”

The Definition of Bioregions in Palaeontological Studies of Diversity and Biogeography Affects Interpretations: Palaeozoic Tetrapods as a Case Study

“…Unfortunately, the definition of bioregions in palaeontological studies of historical biogeography, beta diversity and regional species richness has been inconsistent and often extremely arbitrary. A wide range of scales has been employed, ranging from individual localities (Sahney et al, 2010;Vavrek and Larsson, 2010), to formations/basins (Sidor et al, 2013) to environmental/climatic zones (Sepkoski, 1988;Tougard, 2001;Qian and Ricklefs, 2007;Brocklehurst et al, 2017) to continents (Murray, 2001;Upchurch et al, 2002;Allwood et al, 2010;Benson et al, , 2016Upchurch P. et al, 2015;Dunhill et al, 2016;Silvestro et al, 2016). More recently, Button et al (2017) attempted to remove the subjectivity, grouping localities based on their palaeocoordinates using k-means clustering.…”