See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/225424245 The position of the claws in Noasauridae (Dinosauria: Abelisauroidea) and its implications for abelisauroid manus... Article in Paläontologische Zeitschrift · June 2009 DOI: 10.1007/s12542-009-0044-2 CITATIONS READS 10 119 2 authors: Federico Agnolin Pablo Chiarelli Museo Argentino de Ciencias Naturales "Bern… 1 PUBLICATION 10 CITATIONS 152 PUBLICATIONS 1,256 CITATIONS SEE PROFILE SEE PROFILE All content following this page was uploaded by Federico Agnolin on 08 March 2016. The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. Pala¨ontol Z DOI 10.1007/s12542-009-0044-2 RESEARCH PAPER The position of the claws in Noasauridae (Dinosauria: Abelisauroidea) and its implications for abelisauroid manus evolution Federico L. Agnolin • Pablo Chiarelli Received: 14 April 2009 / Accepted: 24 October 2009 Ó Springer-Verlag 2009 Abstract In this note we reassess the position of putative occurs plesiomorphically in most basal theropods (e.g., pedal phalanges of some South American noasaurid thero- Coelophysis). pods (Abelisauroidea). Noasaurids were considered as to be distinctive abelisauroids with a peculiar ‘‘sickle claw’’ on Keywords Abelisauroidea Á Noasauridae Á Phalanges Á the second toe of the foot, convergently developed with that Cretaceous Á Argentina of deinonychosaurians. Among noasaurids, the Argentinean species Noasaurus leali (latest Cretaceous) and Ligabueino Kurzfassung In der vorliegenden Studie wird eine Ne- andesi (Early Cretaceous) are known from incomplete ubewertung der mutmaßlichen Position der Zehenglieder specimens, including dissarticulated non-ungueal pha- su¨damerikanischer noasaurider Theropoden (Abelisauroidea) langes, and, in N. leali, a claw. A detailed overview of these pra¨sentiert. Noasauride werden als unverwechselbare Abelis- elements indicates that the supposed raptorial claw of the auroide mit einer besonderen ‘‘Sichelkralle’’ am zweiten Zeh second pedal digit of N. leali actually belongs to the first or des Fußes, die konvergent zu der der Deinonychosaurier ent- second finger of the manus, and the putative pedal non- stand ist, betrachtet. Die beiden argentinischen Arten Noa- ungual phalanges of both genera also pertain to the manus. saurus leali (oberste Kreide) und Ligabueino andesi Thus, the new interpretations of noasaurid pedal morphol- (Unterkreide), die beide zu den Noasauriden geho¨ren, sind nur ogy blur the distinctions between Noasauridae and Veloci- durch unvollsta¨ndigen Exemplaren einschließlich nicht-ung- sauridae proposed by previous authors. Finally, we suggest, ualer Zehenglieder und einer Kralle von N. leali belegt. Eine on the basis of phalangeal and metacarpal morphology, that ausfu¨hrliche Untersuchung dieser Elemente deutet darauf hin, abelisaurids probably lost their manual claws by means of dass die angeblich ra¨uberische Kralle der zweiten Zehe von the loss of function of the HOXA11 and HOXD11 genes. N. leali tatsa¨chlich zum ersten oder zweiten Finger der Hand Thus Noasauridae differs from Abelisauridae in retaining geho¨rt. Ebenso geho¨ren auch die nicht-ungualen Zehenglieder plesiomorphic long forelimbs with well developed claws, as beider Taxa zur Hand. Die unterschiedliche Fußmorphologie, wie sie von verschiedenen Autoren vorgeschlagen wurde, beeintra¨chtigt die Unterscheidung zwischen Noasauriden und Velocisauriden. Wir vermuten auf Grund der Phalangen- und F. L. Agnolin (&) Laboratorio de Anatomı´a Comparada y Evolucio´n de los Metacarpaliamorphologie, dass der Verlust der Funktion der Vertebrados, Museo Argentino de Ciencias Naturales HOXA11- und HOXD11-Gene mo¨glicherweise fu¨rdasFeh- ‘‘Bernardino Rivadavia’’, Avenida A´ ngel Gallardo 470 len von Fingerkrallen bei den Abelisauriden verantwortlich (C1405DJR), Buenos Aires, Argentina ist. Somit unterscheiden sich die Noasauriden von den e-mail: [email protected] Abelisauriden durch den Besitz der plesiomorphen langen F. L. Agnolin Á P. Chiarelli Vorderextremita¨ten mit gut-entwickelten Krallen, wie es auch Fundacio´n de Historia Natural ‘‘Fe´lix de Azara’’, bei basalen Theropoden (z.B. Coelophysis) der Fall ist. Departamento de Ciencias Naturales y Antropologı´a, CEBBAD, Universidad Maimo´nides, Valentı´n Virasoro 732 (1405), Buenos Aires, Argentina Schlu¨sselwo¨rter Abelisauroidea Á Noasauridae Á e-mail: [email protected] Phalangen Á Kreide Á Argentinien 123 F. L. Agnolin, P. Chiarelli Abbreviations Province, northwestern Argentina; Lecho Formation, FMNH PR Field Museum of Natural History, Chicago, Maastrichtian, latest Cretaceous; Bonaparte and Powell USA 1980)andLigabueino andesi (La Amarga locality, Neuque´n MACN-PV-N Coleccio´n de Paleontologı´a de Vertebrados, Province, northern Patagonia, Argentina; La Amarga Provincia de Neuque´n,MuseoArgentinode Formation, Barremian-early Aptian, Early Cretaceous; Ciencias Naturales ‘‘Bernardino Rivadavia’’, Bonaparte 1996), and we add some new interpretations on Buenos Aires, Argentina noasaurid and abelisaurid manus morphology. PVL Coleccio´n de Paleontologı´a de Vertebrados, In this paper we follow the phylogenetic taxonomy of Instituto Miguel Lillo, Tucuma´n, Argentina Wilson et al. (2003) with the modifications introduced by Carrano and Sampson (2008). We also use the anatomical terminology employed by Carrano (2007). Introduction Reappraisal of the noasaurid manual and pedal Abelisauroidea is a group of very specialized and bizarre anatomy carnivorous dinosaurs that dominated Gondwanan preda- tory niches along the Late Cretaceous (Bonaparte 1986, In the following section we discuss the morphology of the 1991a; Sereno et al. 2004). These dinosaurs inhabited ter- supposed pedal phalanges of both Noasaurus leali, and restrial ecosystems together with a large array of endemic Ligabueino andesi. Because the phalanges of these genera and allochtonous theropods, for example, basal tetanurans have been described by previous authors this brief over- (e.g., Carcharodontosauridae, Megaraptor; Apesteguı´a view emphasizes traits that allow us to recognize the 2002; Novas et al. 2005a), and coelurosaurs (e.g., Alv- manual or pedal nature of noasaurid phalanges. arezsauridae; Bonaparte 1991a, b; Novas 1997). At least in Early and early Late Cretaceous times (Aptian through Ungual phalanges Cenomanian), together with the Carcharodontosauridae, abelisaurids constituted the dominant predatory dinosaurs Recent works have stressed the apomorphic morphology of southern continents (Bonaparte 1986). present in the abelisaurid pedal claws. As observed by To date, Abelisauroidea comprises two morphologically Novas and Bandyopadhyay (2001), these phalanges bear a divergent theropod subclades: the mid-sized Abelisauridae well defined ‘‘Y’’-shaped system of lateral grooves, a lat- and the small to mid-sized Noasauridae (Bonaparte 1991a), eral tuberosity, and a deep ventral concavity, presumably a phylogenetic arrangement recently confirmed by multiple for flexor tendon attachment (see also Novas et al. 2005b; cladistic analyses (Wilson et al. 2003; Sereno et al. 2004; Maganuco et al. 2008) that probably replaced in function Carrano and Sampson 2008; Canale et al. 2009). However, a the flexor tubercle exhibited by other theropods (Bonaparte few authors (Bonaparte 1991b; Agnolin et al. 2003) pro- and Powell 1980). posed the existence of a third abelisauroid subclade: Ve- On the other hand, noasaurid pedal unguals are very locisauridae Bonaparte 1991b on the basis of the poorly poorly known, being represented only by disarticulated known genus Velocisaurus. As originally understood, one of specimens. The first described purported noasaurid pedal the most striking features of Noasauridae was thought to be ungual phalanx belonged to Noasaurus leali (Bonaparte the presence of a raptorial ‘‘sickle claw’’ assigned to the and Powell 1980). It has an unusual shape for a theropod second pedal digit, morphologically convergent with that of claw, and was regarded as homoplastic with that of the deinonychosaurs (Bonaparte and Powell 1980; Bonaparte dromaeosaurid and troodontid ‘‘sickle claw’’ pedal digit II 1996; see Gauthier 1986). In the original description of (Bonaparte and Powell 1980). Curiously, the Noasaurus Noasaurus leali, Bonaparte and Powell (1980) described a ungual strongly differs from all known abelisauroid pedal single non-ungual phalanx as belonging to the second pedal claws (both abelisaurid and noasaurid; e.g. those of digit. Subsequently, Bonaparte (1996) described Ligabueino Aucasaurus, Ilokelesia, Majungasaurus, and Masiakasau- andesi, and reported the presence of pedal pre-ungual pha- rus; Coria and Salgado 2000; Coria et al. 2002; Carrano langes of uncertain anatomical position. Lately, several et al. 2002; Carrano 2007) in lacking the ‘‘Y’’-shaped isolated ungual and other isolated non-ungual phalanges system of lateral grooves and bump, the large and pro- attributed to noasaurids were described from the latest truding proximodorsal lip, and also in the extreme curva- Cretaceous of India and Madagascar (Carrano et al. 2002; ture of the claw blade (Fig. 1; Novas and Bandyopadhyay Novas et al. 2004). 2001; Sampson et al. 2001; Novas et al. 2004, 2005b). In this note we review the morphology of the known These differences were considered in preliminary analyses phalanges of Noasaurus leali