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A new clade of archaic large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic

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Non-avian theropod dinosaurs attained large body sizes, monopolising terrestrial apex predator niches in the Jurassic-Cretaceous. From the Middle Jurassic onwards, Allosauroidea and Megalosauroidea comprised almost all large-bodied predators for 85 million years. Despite their enormous success, however, they are usually considered absent from terminal Cretaceous ecosystems, replaced by tyrannosaurids and abelisaurids. We demonstrate that the problematic allosauroids Aerosteon, Australovenator, Fukuiraptor and Neovenator form a previously unrecognised but ecologically diverse and globally distributed clade (Neovenatoridae, new clade) with the hitherto enigmatic theropods Chilantaisaurus, Megaraptor and the Maastrichtian Orkoraptor. This refutes the notion that allosauroid extinction pre-dated the end of the Mesozoic. Neovenatoridae includes a derived group (Megaraptora, new clade) that developed long, raptorial forelimbs, cursorial hind limbs, appendicular pneumaticity and small size, features acquired convergently in bird-line theropods. Neovenatorids thus occupied a 14-fold adult size range from 175 kg (Fukuiraptor) to approximately 2,500 kg (Chilantaisaurus). Recognition of this major allosauroid radiation has implications for Gondwanan paleobiogeography: The distribution of early Cretaceous allosauroids does not strongly support the vicariant hypothesis of southern dinosaur evolution or any particular continental breakup sequence or dispersal scenario. Instead, clades were nearly cosmopolitan in their early history, and later distributions are explained by sampling failure or local extinction.
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... Alleged ceratosaurs have previously been reported from Australia: Rauhut (2005) referred the Middle Jurassic Ozraptor subotaii Long and Molnar 1998 to the Abelisauroidea, and Agnolin et al. (2010) referred an Early Cretaceous 'Allosaurus' astragalus (Molnar et al. 1981) to Abelisauroidea. Subsequent study has shown that the former material is not diagnostic (Carrano and Sampson 2008;Agnolin et al. 2010;Barrett et al. 2010) and that the 'Allosaurus' astragalus is assignable to a neovenatorid allosauroid (Hocknull et al. 2009;Benson et al. 2010a; see discussion below). Thus, the fossil described here represents the first diagnostic evidence for the Ceratosauria in Australia and sheds light on the diversity and biogeography of dinosaurs in eastern Gondwana. ...
... NMV P221202 differs from basal Tetanurae (Rauhut 2003;Carrano and Sampson 2008) in having: a coossified astragalus and calcaneum; an ascending process of the astragalus with an approximately parallel-sided base; and a distinct fossa at the base of the ascending process that is not associated with a transverse groove. NMV P221202 differs from megaraptoran allosauroids (Benson et al. 2010a) and Coelurosauria (Welles and Long 1974) in having: an ascending process that is less than twice the dorsoventral depth of the body of the astragalus; and a calcaneum that retains a large fibular facet. Although the astragalus and calcaneum co-ossify in some maniraptorans (e.g. ...
... The astragalus NMV P150070 is sister to Australovenator in both of the pruned MPTs (Fig. 2b, c). This result supports the arguments of Hocknull et al. (2009), Benson et al. (2010a, and this study (see Electronic Supplementary Material) in considering NMV P150070 a neovenatorid allosauroid, contra proposed abelisauroid affinities for this specimen (Agnolin et al. 2010). Although the results of these analyses corroborate our inclusion of NMV P221202 in Ceratosauria, we consider the hypothesized relationships of NMV P221202 within Ceratosauria to be inconclusive pending additional character support. ...
... By contrast, this is a very uncommon treat in noncoelurosaurian tetanurans, where only the megalosaurid Wiehenvenator (Rauhut et al. 2016) and the metriacanthosaurid Siamotyrannus exhibit similar condition. Despite the basal carcharodontosaurid, Concavenator has been codified as having flat ventral surface (Benson et al. 2010;Carrano et al. 2012), a recent review of its axial skeleton indicates that at least the anterior caudal vertebra have a ventral groove . In this regard the ventral surface of IPS137683 is almost flat but it possesses a very fine keel on the anterior half of the caudal centrum. ...
... Malafaia et al. 2019Chokchaloemwong et al. 2019;Coria et al. 2020;Comes da;Gomesda Costa Pereira et al. 2020). The narrow longitudinal groove in the ventral surface, bounded by faint keels in the caudal centrum is also commonly found in Abelisauroidea, Allosauroidea -especially carcharodontosauridsand Megalosauroidea (Ezcurra and Méndez 2009;Benson et al. 2010;Mateus et al. 2011;Carrano et al. 2012;Rauhut et al. 2016;Malafaia et al. 2017Malafaia et al. , 2019Coria et al. 2020). Carrano (2024) mentioned a considerable dorsoventral reduction in the caudal transverse processes of Allosauroidea, a feature that seems alto exhibit IPS137684. ...
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... Tetanurae, Avetheropoda, Coelurosauria), but no further owing to their incompleteness . The presence of Neovenatoridae is possibly symptomatic of a previous nesting of Megaraptora within Neovenatoridae coupled with a cautious approach by the authors on these isolated remains (Benson et al., 2010b. More recently described specimens indicate the presence of the Megaraptoridae (Poropat et al., 2019), Noasauridae (Brougham et al., 2020) and Elaphrosaurinae in the Victorian Cretaceous. ...
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... Carcharodontosauria Benson et al., 2010Carcharodontosauridae Stromer, 1931 Carcharodontosauridae gen. et sp. ...
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... However, given the absence of a preserved neural arch, we cannot assign it to Baryonychinae or Spinosaurinae. CarcharodontosauriaBenson, Carrano and Brusatte, 2010 Gen. et sp. Indet. ...
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