A new choristodere (Reptilia: Diapsida) from the Lower Cretaceous of western Liaoning Province, China, and phylogenetic relationships of Monjurosuchidae

Gao, Ke‐Qin; Fox, Richard C.

doi:10.1111/j.1096-3642.2005.00191.x

Cited by 425 publications

(71 citation statements)

References 18 publications

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“…They are relatively rare components of the fossil record, known from only a dozen or so genera, but range through the Middle Jurassic to the Miocene (Evans & Klembara, 2005). The timing of the radiation of the non-neochoristodere group, Monjurosuchidae, is a point of ongoing study, although their origin might be in the Early Cretaceous of Asia (Gao & Fox, 2005;Averianov et al, 2006;Richter et al, 2010;Gao et al, 2013). The earliest records of the major lineage Neochoristodera occur in Barremian (Early Cretaceous) deposits of Asia (Matsumoto & Evans, 2010) and North America (Britt et al, 2006), and this lineage persisted well past the K/Pg boundary (Evans & Klembara, 2005).…”

Section: (G) Choristoderesmentioning

confidence: 99%

Biotic and environmental dynamics through theLateJurassic–EarlyCretaceous transition: evidence for protracted faunal and ecological turnover

et al. 2016

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The Late Jurassic to Early Cretaceous interval represents a time of environmental upheaval and cataclysmic events, combined with disruptions to terrestrial and marine ecosystems. Historically, the Jurassic/Cretaceous (J/K) boundary was classified as one of eight mass extinctions. However, more recent research has largely overturned this view, revealing a much more complex pattern of biotic and abiotic dynamics than has previously been appreciated. Here, we present a synthesis of our current knowledge of Late Jurassic-Early Cretaceous events, focusing particularly on events closest to the J/K boundary. We find evidence for a combination of short-term catastrophic events, large-scale tectonic processes and environmental perturbations, and major clade interactions that led to a seemingly dramatic faunal and ecological turnover in both the marine and terrestrial realms. This is coupled with a great reduction in global biodiversity which might in part be explained by poor sampling. Very few groups appear to have been entirely resilient to this J/K boundary 'event', which hints at a 'cascade model' of ecosystem changes driving faunal dynamics. Within terrestrial ecosystems, larger, more-specialised organisms, such as saurischian dinosaurs, appear to have suffered the most. Medium-sized tetanuran theropods declined, and were replaced by larger-bodied groups, and basal eusauropods were replaced by neosauropod faunas. The ascent of paravian theropods is emphasised by escalated competition with contemporary pterosaur groups, culminating in the explosive radiation of birds, although the timing of this is obfuscated by biases in sampling. Smaller, more ecologically diverse terrestrial non-archosaurs, such as lissamphibians and mammaliaforms, were comparatively resilient to extinctions, instead documenting the origination of many extant groups around the J/K boundary. In the marine realm, extinctions were focused on low-latitude, shallow marine shelf-dwelling faunas, corresponding to a significant eustatic sea-level fall in the latest Jurassic. More mobile and ecologically plastic marine groups, such as ichthyosaurs, survived the boundary relatively unscathed. High rates of extinction and turnover in other macropredaceous marine groups, including plesiosaurs, are accompanied by the origin of most major lineages of extant sharks. Groups which occupied both marine and terrestrial ecosystems, including crocodylomorphs, document a selective extinction in shallow marine forms, whereas turtles appear to have diversified. These patterns suggest that different extinction selectivity and ecological processes were operating between marine and terrestrial ecosystems, which were ultimately important in determining the fates of many key groups, as well as the origins of many major extant lineages. We identify a series of potential abiotic candidates for driving these patterns, including multiple bolide impacts, several episodes of flood basalt eruptions, dramatic climate change, and major disruptions to oceanic systems. The J/K t...

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Section: (G) Choristoderesmentioning

confidence: 99%

Biotic and environmental dynamics through theLateJurassic–EarlyCretaceous transition: evidence for protracted faunal and ecological turnover

et al. 2016

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“…2-b): the long-necked Japanese Shokawa (Evans and Manabe, 1999) and Chinese Hyphalosaurus (Gao et al, 1999;Ji et al, 2004;Gao and Ksepka, 2008); the longirostrine gavial-like neochoristoderes Tchoiria (Mongolia, Efimov, 1979) and Ikechosaurus (Mongolia, China, Brinkman and Dong, 1993;Liu, 2004); the small lizard-like Monjurosuchus (China, Japan, Gao et al, 2000;Matsumoto et al, 2007) and Philydrosaurus (China, Gao and Fox, 2005;Gao et al, 2007); and the problematic Khurendukhosaurus (Mongolia, Sigogneau- Russell and Efimov, 1984;Skutschas, 2008;Matsumoto et al, 2009). At this time, Eastern Eurasia was divided into two paleophytogeographic provinces: a northern Siberian-Canadian Region (Vakhrameev, 1978), with Tetori-type floras at its southern margin (Kimura, 1979) and a temperate to humid climate; and a southern Euro-Sinian Region (Vakhrameev, 1978) with Ryosekitype floras (Kimura, 1979) and a suggested subtropical to tropical climate, with an annual dry season.…”

Section: Lower Cretaceousmentioning

confidence: 99%

“…The more basal 'non-neochoristoderes' are smaller (0.3-1.0m) and more diverse in their morphology. Cteniogenys (MiddleLate Jurassic, Euramerica, Evans 1990), Lazarussuchus (Oligocene-Miocene, Europe, Hecht, 1992;Evans and Klembara, 2005), Monjurosuchus (Early Cretaceous, China and Japan, Gao et al, 2000;Matsumoto et al, 2007), and Philydrosaurus (Early Cretaceous, China, Gao and Fox, 2005) are essentially lizard-like choristoderes with short necks and either open (Cteniogenys) or closed (the other three) lower temporal fenestrae, whereas the Early Cretaceous Shokawa (Japan, Evans and Manabe, 1999) and Hyphalosaurus (China, Gao et al, 1999), the Hyphalosauridae of Gao et al (2008), are nothosauriform with elongated necks. Khurendukhosaurus (Early Cretaceous, Mongolia, Sigogneau- Efimov, 1984, Skutchas 2008;Matsumoto et al, 2009) is of similar/ or slightly larger size to Hyphalosaurus (holotype, IVPP V11075)…”

Section: Introductionmentioning

confidence: 99%

“…Most recently, the genus Liaoxisaurus was named on the basis of a new specimen from the Jiufotang Formation of China , but it is closely similar to Ikechosaurus pijiagouensis from the same horizon and its validity as a distinct taxon is in doubt. (Hecht, 1992) -g) Hyphalosaurus baitaigouensis (redrawn from Gao and Ksepka, 2008) -h) Monjurosuchus splendens (Matsumoto et al, 2007) -i) Philydrosaurus proseilus (Gao and Fox, 2005 …”

Section: Introductionmentioning

confidence: 99%

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Choristoderes and the freshwater assemblages of Laurasia

Matsumoto¹,

Evans²

2010

J. iber. geol.

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Choristoderes are freshwater aquatic diapsid reptiles of uncertain phylogenetic position. Although the lineage probably diverged from other diapsids in the Permo-Triassic, choristoderes apparently never reached Gondwana. Within Laurasia, however, they have been recovered from Japan, China, Mongolia, Trans-Baikal Russia, Central Asia, Western Europe, and North America, reaching extreme northern latitudes. Setting aside controversial Triassic records, their known temporal range currently extends from the Middle Jurassic (Britain, Kyrgyzstan) to the Miocene (Czech Republic). However, although small choristoderes are known to span the entirety of this period, the larger, more derived neochoristoderes are recorded only from the Early Cretaceous through to the earliest Eocene. The gavial-like neochoristodere Champsosaurus is the most familiar taxon, characterised by large size, a long rostrum and flared temporal fenestrae, but research over the last three decades has revealed many new genera and exposed an unexpected diversity in terms of body size (small to relatively large), neck length (long v. short) and skull morphology (longirostrine v. brevirostrine, open v. closed lower temporal fenestrae). Typically choristoderes occur as part of a mesic assemblage that includes fish, lizards, mammals, turtles, frogs, salamanders, small dinosaurs and, usually, crocodiles. At maturity, Jurassic choristoderes were generally smaller than co-occuring crocodiles and were relatively unspecialized postcranially. The Early Cretaceous of Asia saw a dramatic diversification of choristoderes, including the appearance of much larger neochoristoderes. Perhaps significantly, the relevant Asian horizons (e.g. Yixian Formation, China; Okurodani and Kuwajima formations, Japan) yield no crocodiles. In Late Cretaceous and Paleogene horizons however, across Euramerica, large gavial-like neochoristoderes came to share freshwater ecosystems with a diversity of crocodiles, the neochoristoderes apparently occupying a specialist (gavial-like) piscivorous niche as long as it was available and resources were adequate.

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“…The scapula and coracoid are not fused. The scapula is a slender flask-like element with a narrow blade and wider base, similar to these of Philydrosaurus proseilus (Gao and Fox, 2005) and Monjurosuchus splendens . The coracoid is partially exposed at its proximal end, it is broad and round.…”

Section: Descriptionmentioning

confidence: 99%