Science, Год журнала: 2022, Номер 375(6578)
Опубликована: Янв. 20, 2022
Schroeder et al. (Reports, 26 February 2021, p. 941) reported a size gap among predatory dinosaur species. We argue that the supporting dataset is skewed toward Late Cretaceous North America and was likely absent during other intervals in most geographic regions. urge broader consideration of this hypothesis, with quantitative evaluation preservational biases.
Язык: Английский
Historical Biology, Год журнала: 2021, Номер 34(9), С. 1717 - 1751
Опубликована: Окт. 4, 2021
The Late Jurassic, 'single surface' Moab Megatracksite between Green River, Utah and the Colorado-Utah State line is associated with sharp, colour-enhanced, inter-formational contact white, reworked dune sandstones from aeolian Member of Curtis Formation red, sabkha facies siltstones upper tongue Summerville Formation. Previous studies described theropod (Megalosauripus Therangospodus) dominated assemblages ~25 sites in megatracksite core area around Arches National Park, briefly interpreted transgressive mechanisms Sundance sea which helped create preserve megatracksite.Since 1990s ~20 newly studied tracksites reveal a cumulative total ~4,300 tracks three are now designated as, federally managed, interpretative tourist destinations. Similar track assemblages, collectively constituting Megalosauripus-Therangospodus ichnocoenoses have also been found at lower stratigraphical levels J-3 Unconformity zones. These new discoveries relate to stratigraphic short-term changes Sea level affecting coastal (Slick Rock members) across low gradient, inter- sub-tidal sand flats, sabkha-like deposits under arid conditions. multiple (>50) ichnofaunas integral palaeobiological understanding an no body fossils known.
Язык: Английский
Процитировано
12
Historical Biology, Год журнала: 2021, Номер 34(11), С. 2230 - 2240
Опубликована: Дек. 8, 2021
It has been argued that, throughout the Mesozoic, immature growth forms of megaherbivorous dinosaurs competitively excluded small herbivorous dinosaur species, leading to left-skewed species richness-body mass distributions their fossil assemblages. By corollary, where large and herbivores coexisted over a geologically significant period time, they must have exhibited niche partitioning. We use multivariate ecomorphological analysis Late Cretaceous ornithischian assemblage North America examine this prediction. Our results indicate good separation most, but not all, at body size, although more work is required demonstrate that these patterns were adaptive. Calculation browse profiles using corrected abundance data bracketed estimates energy requirements suggests megaherbivores – most particularly hadrosaurids outstripped coexisting in control resource base.
Язык: Английский
Процитировано
11
Lethaia, Год журнала: 2021, Номер 54(5), С. 969 - 987
Опубликована: Дек. 1, 2021
The Mesozoic and Cenozoic track record of large birds (avian theropods) with footprint lengths (FL) > 10.0 cm is quite limited, whereas small tracks (FL < cm) are abundant from the Early Cretaceous onwards. This versus threshold value consistent extant among which only ˜10% large, so scaled appropriately to Class Aves. proportion pachydactylous (thick-toed) or robust non-avian theropod ichnotaxa reported considerably exceeds few leptodactylous (thin-toed) gracile forms such as Archaeornithipus Magnoavipes, named, albeit controversially, suggest avian affinity. different, limited a Eocene-Oligocene (Palaeogene) ichnogenera (Ornithoformipes Rivavipes), rare unnamed Neogene Holocene dinornithiform tracks. Thus, flightless species less well represented by than body fossils. suggests probable preservational bias in favour waterbird shorebird-like shoreline facies. However, attributable cranes, herons related trackmakers extensive, mostly confined formally named representatives clades capable flight. These distribution patterns apparently reflect dominance theropods early Palaeogene, contrast rise ongoing diversification smaller Aequornithes Neogene. space time likely changing selection pressures today's modern avifauna evolved.
Язык: Английский
Процитировано
11
Cretaceous Research, Год журнала: 2021, Номер 130, С. 105061 - 105061
Опубликована: Окт. 19, 2021
Язык: Английский
Процитировано
10
Science, Год журнала: 2022, Номер 375(6578)
Опубликована: Янв. 20, 2022
Schroeder et al. (Reports, 26 February 2021, p. 941) reported a size gap among predatory dinosaur species. We argue that the supporting dataset is skewed toward Late Cretaceous North America and was likely absent during other intervals in most geographic regions. urge broader consideration of this hypothesis, with quantitative evaluation preservational biases.
Язык: Английский
Процитировано
7