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Today, warm-water coral reefs are limited to tropical-to-subtropical latitudes. These diverse ecosystems extended further poleward in the geological past, but the mechanisms driving these past distributions remain uncertain. Here, we test the role of climate and palaeogeography in shaping the distribution of coral reefs over geological timescales. To do so, we combine habitat suitability modelling, Earth System modelling and the ~247-million-year geological record of scleractinian coral reefs. A broader latitudinal distribution of climatically suitable habitat persisted throughout much of the Mesozoic–early Paleogene due to an expanded tropical belt and more equable distribution of shallow marine substrate. The earliest Cretaceous might be an exception, with reduced shallow marine substrate during a 'cold-snap' interval. Climatically suitable habitat area became increasingly skewed towards the tropics from the late Paleogene, likely steepening the latitudinal biodiversity gradient of reef-associated taxa. This was driven by global cooling and increases in tropical shallow marine substrate resulting from the tectonic evolution of the Indo-Australian Archipelago. Although our results suggest global warming might permit long-term poleward range expansions, coral reef ecosystems are unlikely to keep pace with the rapid rate of anthropogenic climate change. Warm-water coral reefs are limited to tropical and subtropical latitudes today but extended poleward in the geological past. This study shows that climatic and tectonic drivers explain the past distribution of coral reefs and associated biodiversity. [ABSTRACT FROM AUTHOR]

Dinosaur remains were discovered in the 1860’s in the Kimmeridgian (Late Jurassic) Reuchenette Formation of Moutier, northwestern Switzerland. In the 1920’s, these were identified as a new species of sauropod, Ornithopsis greppini, before being reclassified as a species of Cetiosauriscus (C. greppini), otherwise known from the type species (C. stewarti) from the late Middle Jurassic (Callovian) of the UK. The syntype of “C. greppini” consists of skeletal elements from all body regions, and at least four individuals of different sizes can be distinguished. Here we fully re-describe this material, and re-evaluate its taxonomy and systematic placement. The Moutier locality also yielded a theropod tooth, and fragmentary cranial and vertebral remains of a crocodylomorph, also re-described here. “C.” greppini is a small-sized (not more than 10 m long) non-neosauropod eusauropod. Cetiosauriscus stewarti and “C.” greppini differ from each other in: (1) size; (2) the neural spine morphology and diapophyseal laminae of the anterior caudal vertebrae; (3) the length-to-height proportion in the middle caudal vertebrae; (4) the presence or absence of ridges and crests on the middle caudal centra; and (5) the shape and proportions of the coracoid, humerus, and femur. These anatomical differences, combined with their discrepancy in stratigraphic age, make it unlikely that C. stewarti and “C.” greppini belong to the same genus, as also supported through our phylogenetic analysis. “C.” greppini cannot be assigned to any other contemporaneous sauropod taxon from Europe, but is diagnosed by an autapomorphic rugosity on the posteromedial margin of the humerus, as well as a unique combination of features. As such, we erect the new genus name Amanzia for the Swiss taxon “Ornithopsis” greppini, augmenting the growing diversity of Late Jurassic European sauropods. Our phylogenetic analysis places it outside of Neosauropoda, either as the sister taxon to that clade, or as a member of Turiasauria. [ABSTRACT FROM AUTHOR]

The fragmentation of the supercontinent Pangaea has been suggested to have had a profound impact on Mesozoic terrestrial vertebrate distributions. One current paradigm is that geographic isolation produced an endemic biota in East Asia during the Jurassic, while simultaneously preventing diplodocoid sauropod dinosaurs and several other tetrapod groups from reaching this region. Here we report the discovery of the earliest diplodocoid, and the first from East Asia, to our knowledge, based on fossil material comprising multiple individuals and most parts of the skeleton of an early Middle Jurassic dicraeosaurid. The new discovery challenges conventional biogeographical ideas, and suggests that dispersal into East Asia occurred much earlier than expected. Moreover, the age of this new taxon indicates that many advanced sauropod lineages originated at least 15 million years earlier than previously realised, achieving a global distribution while Pangaea was still a coherent landmass. [ABSTRACT FROM AUTHOR]

The original version of the Supplementary Information associated with this Article contained an error in Supplementary Figures 6, 8, 11, in which the x-axes labels read 10 SP 6 sp km SP 2 sp instead of 10 SP 5 sp km SP 2 sp . This has been corrected in both the PDF and HTML versions of the Article. [Extracted from the article]

In the lead-up to the Cretaceous/Paleogene mass extinction, dinosaur diversity is argued to have been either in long-term decline, or thriving until their sudden demise. The latest Cretaceous (Campanian-Maastrichtian [83-66 Ma]) of North America provides the best record to address this debate, but even here diversity reconstructions are biased by uneven sampling. Here we combine fossil occurrences with climatic and environmental modelling to quantify latest Cretaceous North American dinosaur habitat. Ecological niche modelling shows a Campanian-to-Maastrichtian habitability decrease in areas with present-day rock-outcrop. However, a continent-wide projection demonstrates habitat stability, or even a Campanian-to-Maastrichtian increase, that is not preserved. This reduction of the spatial sampling window resulted from formation of the proto-Rocky Mountains and sea-level regression. We suggest that Maastrichtian North American dinosaur diversity is therefore likely to be underestimated, with the apparent decline a product of sampling bias, and not due to a climatically-driven decrease in habitability as previously hypothesised. The fossil record shows a decline in dinosaur diversity preceding their mass extinction. Here, the authors apply ecological niche modelling to show that suitable dinosaur habitat was declining in areas with present-day rock-outcrop, but not across North America as a whole, possibly generating sampling bias in the fossil record. [ABSTRACT FROM AUTHOR]