New theropod remains from the Tiourarén Formation (?Middle Jurassic, Niger) and their bearing on the dental evolution in basal tetanurans

Serrano-Martínez, Alejandro; Sciscio, Lara; Tent-Manclús, José Enrique; Bandera, Ignacio Fierro; Knoll, Fabien

doi:10.1016/j.pgeola.2014.10.005

Cited by 26 publications

(11 citation statements)

References 48 publications

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“…The temporal range, as well as the spatial range of spinosaurs is significantly increased when more ambiguous identifications are included. Oldest possible spinosaurid occurences include the isolated tooth described as Ostafrikasaurus from the Late Jurassic of Tendaguru ( Buffetaut, 2008 ; Buffetaut, 2012 though see Rauhut, 2011 ) and isolated teeth showing spinosaurid characteristics from the late Middle Jurassic of Niger ( Serrano–Martínez et al, 2015 ), and youngest have been reported from the Santonian of China ( Hone, Xu & Wang, 2010 ). Another possible spinosaur is Chilantaisaurus Hu, 1964, the systematic position of which has been a matter of debate ( Rauhut, 2003 ; Benson & Xu, 2008 ; Allain et al, 2012 ).…”

Section: Discussionmentioning

confidence: 99%

A reappraisal of the morphology and systematic position of the theropod dinosaurSigilmassasaurusfrom the “middle” Cretaceous of Morocco

Evers

Rauhut

Milner

et al. 2015

PeerJ

135

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Sigilmassasaurus brevicollis is an enigmatic theropod dinosaur from the early Late Cretaceous (Cenomanian) of Morocco, originally based on a few isolated cervical vertebrae. Ever since its original description, both its taxonomic validity and systematic affinities were contentious. Originally considered to represent its own family, Sigilmassasauridae, the genus has variously been suggested to represent a carcharodontosaurid, an ornithischian, and, more recently, a spinosaurid. Here we describe new remains referrable to this taxon and re-evaluate its taxonomic status and systematic affinities. Based on the new remains, a re-evaluation of the original materials, and comparisons with other spinosaurids, the holotype of Sigilmassasaurus brevicollis is identified as an anterior dorsal, rather than a cervical vertebra, and differences between elements referred to this taxon can be explained by different positions of the elements in question within the vertebral column. Many characters used previously to diagnose the genus and species are found to be more widespread among basal tetanurans, and specifically spinosaurids. However, the taxon shows several autapomorphies that support its validity, including the presence of a strongly rugose, ventrally offset triangular platform that is confluent with a ventral keel anteriorly in the mid-cervical vertebral centra and a strongly reduced lateral neural arch lamination, with no or an incomplete distinction between anterior and posterior centrodiapophyseal laminae in the posterior cervical and anterior dorsal vertebrae. We argue furthermore that Spinosaurus maroccanus, also described on the basis of isolated cervical vertebrae from the same stratigraphic unit and in the same paper as Sigilmassasaurus brevicollis, is a subjective synonym of the latter. Both a detailed comparison of this taxon with other theropods and a formal phylogenetic analysis support spinosaurid affintities for Sigilmassasaurus. However, we reject the recently proposed synonymy of both Spinosaurus maroccanus and Sigilmassasurus brevicollis with Spinosaurus aegyptiacus from the Cenomanian of Egypt, as there are clear differences between the vertebrae of these taxa, and they do not share any derived character that is not found in other spinosaurids. Together with a comparison with other spinosaurid vertebral material from the Kem Kem, this suggests that more than one taxon of spinosaurid was present in the Kem Kem assemblage of Morocco, so the referral of non-overlapping material from this unit to a single taxon should be regarded with caution.

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Section: Discussionmentioning

confidence: 99%

A reappraisal of the morphology and systematic position of the theropod dinosaurSigilmassasaurusfrom the “middle” Cretaceous of Morocco

Evers

Rauhut

Milner

et al. 2015

PeerJ

135

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“…The Tiouraren Formation has traditionally been regarded as Early Cretaceous (e.g., Moody and Sutcliffe, 1991;Sereno et al, 1994Sereno et al, , 2004, but Rauhut and López-Arbarello (2009) argued that it is considerably older, and probably Middle to earliest Late Jurassic in age. This assignment has been widely accepted since (e.g., Remes et al, 2009;Mudroch et al, 2011;Serrano-Martínez et al, 2015;van Damme et al, 2015), with most authors favouring a late Middle Jurassic age. This is the age assumed here as well.…”

Section: Theropod Faunal Changes From the Middle To The Late Jurassicmentioning

confidence: 99%

A new megalosaurid theropod dinosaur from the late Middle Jurassic (Callovian) of north-western Germany: Implications for theropod evolution and faunal turnover in the Jurassic

Rauhut¹,

Hübner²,

Lanser

2016

Palaeontologia Electronica

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Fragmentary remains of a large, robustly built theropod dinosaur were recovered from the marine middle Callovian Ornatenton Formation of northeastern Northrhine-Westphalia, Germany. The specimen includes a premaxilla, maxilla, lacrimal, postorbital, dentary, several caudal vertebrae, ribs, fibulae, astragalus, and partial calcaneum. It is here described as a new species of megalosauroid, Wiehenvenator albati n. gen. n. sp., diagnosed by a strongly reduced maxillary antorbital fossa on the base of the ascending process of the maxilla, a very short anterior ramus of the lacrimal with an additional pneumatic depression anteroventral to the lacrimal fenestra, a transversely expanded orbital facet in the postorbital, and a laterally flexed proximal end of the ascending process of the astragalus. Phylogenetic analysis recovers Wiehenvenator as a megalosaurine megalosaurid, sister taxon to the Late Jurassic genus Torvosaurus. It thus adds to the considerable diversity of megalosauroids in the Middle Jurassic. A time-calibrated phylogeny of theropods indicates a rapid radiation of averostran theropods between the Toarcian and the Bathonian. This radiation was probably triggered by the Pliensbachian-Toarcian extinction event, which might have been more important for theropod evolution than the Triassic-Jurassic extinction. The fossil record indicates a faunal turnover from megalosauroid dominated Middle Jurassic to allosauroid / coelurosaur dominated Late Jurassic faunas. However, differences in the Middle and Late Jurassic theropod fossil records both in respect to geographic distribution of localities, as well as sampled environments make this inference problematic, at least in respect to allosauroids. An analysis of environmental preferences of allosauroids and megalosauroids indicates that the former preferred inland environments, whereas the latter are more common in nearshore environments.

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“…The scarcity of information on theropod tooth morphology leads to taxonomic assignments on the basis of a priori assumptions of their phylogenetic affinities (Smith, 2005). The current literature contains many tooth-based taxonomic assessments based on scarce or poorly understood data (e.g., Soto and Perea, 2008;Buffetaut, 2011;Vullo et al, 2014;Mo and Xu, 2015;Serrano-Martínez et al, 2015. For example, the marginal undulations visible on the crown of some carcharodontosaurids is often considered as a key character of this clade, leading some authors (e.g., Chure et al, 1999) to assign isolated teeth to Carcharodontosauridae solely based on this feature when, in fact, it has a broader taxonomic distribution .…”

Section: Introductionmentioning

confidence: 99%

The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends

Hendrickx

Mateus

Araújo

et al. 2019

Palaeontol Electron

150

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New theropod remains from the Tiourarén Formation (?Middle Jurassic, Niger) and their bearing on the dental evolution in basal tetanurans

Cited by 26 publications

References 48 publications

A reappraisal of the morphology and systematic position of the theropod dinosaurSigilmassasaurusfrom the “middle” Cretaceous of Morocco

A reappraisal of the morphology and systematic position of the theropod dinosaurSigilmassasaurusfrom the “middle” Cretaceous of Morocco

A new megalosaurid theropod dinosaur from the late Middle Jurassic (Callovian) of north-western Germany: Implications for theropod evolution and faunal turnover in the Jurassic

The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends

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