[Paleontology • 2017] Shringasaurus indicus • A New Horned and Long-necked Herbivorous Stem-Archosaur from the Middle Triassic of India ---ScRaBBlE

Shringasaurus indicus 

Sengupta, Ezcurra & Bandyopadhyay, 2017

Illustration: Gabriel Lio

   DOI:  10.1038/s41598-017-08658-8  

Abstract

The early evolution of archosauromorphs (bird- and crocodile-line archosaurs and stem-archosaurs) represents an important case of adaptive radiation that occurred in the aftermath of the Permo-Triassic mass extinction. Here we enrich the early archosauromorph record with the description of a moderately large (3–4 m in total length), herbivorous new allokotosaurian, Shringasaurus indicus, from the early Middle Triassic of India. The most striking feature of Shringasaurus indicus is the presence of a pair of large supraorbital horns that resemble those of some ceratopsid dinosaurs. The presence of horns in the new species is dimorphic and, as occurs in horned extant bovid mammals, these structures were probably sexually selected and used as weapons in intraspecific combats. The relatively large size and unusual anatomy of Shringasaurus indicus broadens the morphological diversity of Early–Middle Triassic tetrapods and complements the understanding of the evolutionary mechanisms involved in the early archosauromorph diversification.

Figure 3: Skeletal anatomy of Shringasaurus indicus gen. et sp. nov. (a) Left premaxilla (ISIR 793) in lateral view. (b) Left maxilla (ISIR 795) in lateral view. (c) Left quadrate (ISIR 797) in lateral view. (d) Axis (ISIR 803) in left lateral view. (e) Posterior cervical vertebra (ISIR 820) in left lateral view. (f,g) Anterior dorsal vertebra (ISIR 825) in left lateral view in (f), and anterior view in (g). (h) Two anterior caudal vertebrae (ISIR 875) in right lateral view (mirrored). (i) Posterior caudal vertebra (ISIR 892) in left lateral view. (j) Right femur (ISIR 1016) in ventral view. (k) Left ilium (ISIR 991) in lateral view. (l), (m) Right astragalus and fused lateral centrale (ISIR 1059) in proximal view in (l), and dorsal view in (m). (n) Interclavicle (ISIR 950) in ventral view. (o) Left clavicle (ISIR 948) in medial view. (p) Left humerus (ISIR 951) in ventral view. (q) Left scapula (ISIR 929) and coracoid (ISIR 941) in lateral view. (r) Tooth crown (ISIR 801A) in labial view.

Scales = 1 cm for (a–c,i,m,l), 2 cm for (d–h,j,k,n–q), and 1 mm for (r), and skeleton = 25 cm. a. articulates with; ac, acetabulum; ain, axial intercentrum; ap, anterior process; ca, calcaneum; ce, lateral centrale; de, denticles; dpc, deltopectoral crest; fi, fibula; gf, glenoid fossa; gr, groove; hqh, hooked quadrate head; icl, interclavicle; itr, internal trochanter; la, lacrimal; lp, lateral process; mp, mammillary process; nag, non-articular gap; pcdl, posterior centrodiapophyseal lamina; pgp, postglenoid process; pnp, postnasal process; pof, popliteal fossa; pop, postacetabular process; pp, parapophysis; ppr, posterior process; ppdl, paradiapophyseal lamina; prdl, prezygodiapophyseal lamina; prp, preacetabular process; prz, prezygapophysis; qj, quadratojugal; sac, supraacetabular crest; sc, scapula; sgl, subglenoid lip; spdl, spinodiapophyseal lamina; sprdl, spinoprezygapophyseal lamina; ti, tibia.

Figure 2: Cranial anatomy of Shringasaurus indicus gen. et sp. nov. and comparison with the skull of a ceratopsid dinosaur that possesses convergent supraorbital horns. (a) Reconstruction of the skull of Shringasaurus indicus in left lateral view. (b) Drawing of the skull of Arrhinoceratops brachyops in left lateral view (based on ROM 79648). (c) Reconstruction of the skull of Shringasaurus indicus in dorsal view. (d–g) Partial skull tables of Shringasaurus indicus in dorsal views (ISIR 781, 780, 786, 789, 790 from left to right), one side has been digitally mirrored in (d–f). (h–k) Partial skull tables of Shringasaurus indicus in left lateral views (ISIR 781, 780, 786, 790 from left to right). Specimens (d–f) and (h–j) possesses horns and specimen/s (g) and (k) lacks horns.

Scales = 4 cm for (a) and ( c–k), and 20 cm for (b). en, external naris; ho, horn; or, orbit; stf, supratemporal fenestra.

Figure 4: Phylogenetic relationships of Shringasaurus indicus gen. et sp. nov. and evolution of body size among early archosauromorphs. (a) Time calibrated strict consensus tree found in the data set analysed here (Supplementary Information). Diapsids more basal than Protorosaurus are not shown and all clades except Allokotosauria have been collapsed for clarity. Numbers at the nodes are Bremer support values higher than 1. (b) Evolution of femoral length (as proxy of body size) optimized as a continuous character using maximum parsimony among non-archosauriform archosauromorphs (Supplementary Information). The horizontal axis represents phylogenetic distance. Green circles represent non-allokotosaurian species, red circles represent allokotosaurians, light blue circles represent non-allokotosaurian ancestral femoral lengths, and violet circles represent allokotosaurian ancestral femoral lengths. The dotted line represents a branch not included in the phylogenetic analysis of this study and the horizontal bar with dotted vertical lines on the right side of the graphic represents the median and standard deviation of Permian to Middle Triassic non-allokotosaurian, non-archosauriform archosauromorph femoral length. a, Crocopoda; b, Allokotosauria; c, Trilophosauridae; d, Azendohsauridae; e, Azendohsaurus.

Systematic Palaeontology

Diapsida Osborn, 1903

Archosauromorpha Huene, 1946 sensu Dilkes19

Allokotosauria Nesbitt et al., 2015

Azendohsauridae Nesbitt et al., 2015

Shringasaurus indicus gen. et sp. nov.

Etymology: ‘Śṛṅga’ (Shringa), horn (ancient Sanskrit), and ‘sauros’ (σαῦρος), lizard (ancient Greek), referring to the horned skull; ‘indicus’, Indian (Latin English), refers to the country where such species was discovered.

Holotype: ISIR (Indian Statistical Institute, Reptile, India) 780: partial skull roof (prefrontal, frontal, postfrontal, and parietal) with a pair of large supraorbital horns (Fig. 2e,i).

Locality and horizon: Near Tekapar village, Hoshangabad district, Madhya Pradesh, India (Fig. 1); Denwa Formation, Anisian, early Middle Triassic18, Satpura Gondwana Basin.

Diagnosis: Relatively large (3–4 m total body length; Fig. S1) allokotosaurian archosauromorph that differs from other stem-archosaurs in the following combination of character-states: confluent external nares; pair of anterodorsally oriented supraorbital horns; similar sized and leaf-shaped marginal and palatal teeth with large denticles; middle-posterior cervical, dorsal, and at least the first two caudal vertebrae with mammillary processes on the neural spines; middle-posterior cervical, dorsal, and sacral vertebrae with hyposphene-hypantrum accessory articulations; cervical vertebrae 2–5 with epipophyses (unknown in Cv6); dorsal vertebrae with spinoprezygapophyseal and spinopostzygapophyseal laminae; dorsal vertebrae 1–12 with spinodiapophyseal laminae; anterior dorsal vertebrae with neural spines two times taller than its respective centrum (see Supplementary Information for differential diagnosis).

Shringasaurus indicus Sengupta, Ezcurra & Bandyopadhyay, 2017

Illustration: Gabriel Lio 

Saradee Sengupta, Martín D. Ezcurra and Saswati Bandyopadhyay. 2017. A New Horned and Long-necked Herbivorous Stem-Archosaur from the Middle Triassic of India.  Scientific Reports. 7, Article number: 8366.  DOI:  10.1038/s41598-017-08658-8

facebook.com/MartinEzcurra98/posts/10214054731864627

 Cómo era el mundo cuando vivía el Shringasaurus indicus 

lanacion.com.ar/2055099 via @LANACION

Encuentran en India un reptil con cuernos de 240 millones de años  conicet.gov.ar/encuentran-en-india-un-reptil-con-cuernos-de-240-millones-de-anos/

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

من هنا

او

من هنا

شاهد هذا الفيديو القصير لطريقة التحميل البسيطة

منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات

كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا

شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا

رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا
شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا

تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا

ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.

[Paleontology • 2017] A Dinosaur Missing-Link? Chilesaurus and the Early Evolution of Ornithischian Dinosaurs ---ScRaBBlE

Chilesaurus diegosuarezi 

Novas, Salgado, Suárez, Agnolín, Ezcurra, Chimento, de la Cruz, Isasi, Vargas & Rubilar-Rogers, 2015

DOI: 10.1098/rsbl.2017.0220  & DOI: 10.1038/nature14307

Illustration: Gabriel Lío

Abstract

The enigmatic dinosaur taxon Chilesaurus diegosuarezi was originally described as a tetanuran theropod, but this species possesses a highly unusual combination of features that could provide evidence of alternative phylogenetic positions within the clade. In order to test the relationships of Chilesaurus, we added it to a new dataset of early dinosaurs and other dinosauromorphs. Our analyses recover Chilesaurus in a novel position, as the earliest diverging member of Ornithischia, rather than a tetanuran theropod. The basal position of Chilesaurus within the clade and its suite of anatomical characters suggest that it might represent a ‘transitional’ taxon, bridging the morphological gap between Theropoda and Ornithischia, thereby offering potential insights into the earliest stages of ornithischian evolution, which were previously obscure. For example, our results suggest that pubic retroversion occurred prior to some of the craniodental and postcranial modifications that previously diagnosed the clade (e.g. the presence of a predentary bone and ossified tendons).

KEYWORDS: Archosauria, Dinosauria, Ornithischia, systematics: phylogeny, Jurassic

Figure 2. Ornithischian features of Chilesaurus. (a) Simplified tree with key acquisitions marked on;
(b) right dentary of Chilesaurus (SNGM-1935) in lateral view; (c) right dentary of Heterodontosaurus (SAM-PK-K1332) in lateral view; (d) pelvic girdle of Chilesaurus SNGM-1936 in lateral view; (e) pelvic girdle of Agilisaurus (ZDM T6011) in lateral view; (f) right femur of Chilesaurus (SNGM-1935) in anterior view; (g) right tibia and fibula of Chilesaurus (SNGM-1935) in posterior view.

Numbers indicate the acquisition of key ornithischian synapomorphies within the clade: 1, complete loss of recurvature in maxillary and dentary teeth; 2, edentulous anterior end of the dentary; 3, predentary bone at the anterior end of the lower jaw; 4, retroversion of the pubis; 5, rod-like pubic shaft; 6, pubic symphysis restricted to the distal end; 7, anteriorly elongate preacetabular process; 8, broadened, wing-like anterior trochanter; 9, fibula less than half the width of the tibia at midshaft. Dark grey circles denote unknown in Pisanosaurus.

Conclusion: 

This study identifies Chilesaurus as a transitional ornithischian taxon and suggests that the unique suite of anatomical features it possesses could be informative not only in unravelling dinosaur interrelationships, but also in shedding light on the evolution of the anatomical peculiarities that characterize ornithischians. Paradoxically, this early diverging lineage is of Late Jurassic age, implying an extensive ghost lineage between it and other ornithischians and basal theropods. If this hypothesis is correct, this ghost lineage suggests that other similar animals await discovery in Late Triassic–Middle Jurassic deposits. This study highlights the importance of broad taxon sampling when attempting to assess the phylogenetic affinities of enigmatic taxa such as Chilesaurus and also demonstrates the utility of this new early dinosaur dataset for testing the relationships proposed for other problematic dinosauromorph taxa.

Matthew G. Baron and Paul M. Barrett. 2017. A Dinosaur Missing-Link? Chilesaurus and the Early Evolution of Ornithischian Dinosaurs. Biology Letters. 13(8); 20170220. DOI: 10.1098/rsbl.2017.0220.

Abstract: Many dinosaur skeletons show evidence of behavior, including feeding, predation, nesting, and parental care. The resting posture of the forelimbs has been studied in some theropod species, in relation to the acquisition of flight in advanced maniraptoran theropods. Chilesaurus diegosuarezi is a bizarre tetanuran recently described from the Toqui Formation (latest Tithonian) of southern Chile that is represented by multiple well-preserved and articulated specimens. The aim of the present work is to analyze the forelimb posture of four articulated specimens of Chilesaurus: SNGM-1935 (holotype), SNGM-1936, SNGM-1937, SNGM-1938; focusing on its anatomical description, and phylogenetic and behavioral implications. All the preserved specimens of Chilesaurus show strongly ventrally flexed arms with the hands oriented backwards, an arrangement that closely resembles those in dinosaur specimens previously described as preserving resting posture, such as Mei long, Sinornithoides youngi, and Albinykus baatar. As a result, it seems that individuals of Chilesaurus have been in passive activity (e.g. feeding, resting) when they were buried quickly, allowing their fossilization in life position and preserving the forelimb resting posture. The arrangement of the forelimb bones in Chilesaurus could show the first evidences of the structures linked to the muscles that flex the forearms, features related with the acquisition of flying control in advanced maniraptorans.

Nicolás R. Chimento, Federico L. Agnolin, Fernando E. Novas, Martín D. Ezcurra, Leonardo Salgado, Marcelo P. Isasi, Manuel Suárez, Rita De La Cruz, David Rubilar-Rogers and Alexander O. Vargas. 2017. Forelimb posture in Chilesaurus diegosuarezi (Dinosauria, Theropoda) and its behavioral and phylogenetic implications. Ameghiniana. in press. DOI: 10.5710/AMGH.11.06.2017.3088.

ResearchGate.net/publication/317546006_FORELIMB_POSTURE_IN_CHILESAURUS_DIEGOSUAREZI

Study identifies dinosaur ‘missing link’

cam.ac.uk/research/news/study-identifies-dinosaur-missing-link

Fernando E. Novas, Leonardo Salgado, Manuel Suárez, Federico L. Agnolín, Martín D. Ezcurra, Nicolás R. Chimento, Rita de la Cruz, Marcelo P. Isasi, Alexander O. Vargas and David Rubilar-Rogers. 2015. An Enigmatic Plant-eating Theropod from the Late Jurassic period of Chile. Nature. (2015) DOI: 10.1038/nature14307

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

من هنا

او

من هنا

شاهد هذا الفيديو القصير لطريقة التحميل البسيطة

منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات

كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا

شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا

رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا
شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا

تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا

ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.

[Paleontology • 2018] Mandasuchus tanyauchen • A Pseudosuchian Archosaur from the Manda Beds (?Middle Triassic) of Tanzania ---ScRaBBlE

Mandasuchus tanyauchen

 Butler, Nesbitt, Charig, Gower & Barrett, 2018

  DOI:  10.1080/02724634.2017.1343728    

ABSTRACT

The diverse assemblage of extinct archosaur species known from the Manda Beds of Tanzania has provided key insights into the timing and tempo of the early part of the archosaur radiation during the Middle Triassic. Several archosaur specimens were collected from the Manda Beds in 1933 by F. R. Parrington, and three of these were subsequently described and made the basis of a new genus, ‘Mandasuchus,’ in a 1956 doctoral dissertation. However, this important fossil material was never formally published, and >60 years later ‘Mandasuchus’ and ‘Mandasuchus tanyauchen’ remain nomina nuda, despite frequent references to them in the literature. Here, we provide a detailed description of this material, provide the first formal diagnosis of Mandasuchus tanyauchen, gen. et sp. nov., and assess its phylogenetic position. The holotype of M. tanyauchen includes a well-preserved partial postcranial skeleton and fragmentary cranial remains. Four referred specimens include two partial skeletons, consisting primary of postcranial remains, a partial maxilla that was previously assigned to the dinosaur clade Saurischia, and a well-preserved astragalus and calcaneum that may belong to the holotype individual. Mandasuchus tanyauchen is diagnosed by a unique combination of character states, as well as by two possible autapomorphies (ascending process of maxilla thin and compressed from anterolateral to posteromedial; femur with distinct pit lateral to the distal-most expression of the posteromedial tuber). Our phylogenetic analysis recovered M. tanyauchen within Paracrocodylomorpha, as the sister taxon to all other sampled members of Loricata.

FIGURE 1. Reconstruction of Mandasuchus and accompanying caption commissioned for the Brooke Bond Picture Card album on ‘Prehistoric Animals’ (Charig and Wilson, 1971).

 twitter.com/ButlerLabBham 

FIGURE 27. Life reconstruction of Mandasuchus tanyauchen, gen. et sp. nov.

created by Mark Witton/Natural History Museum, London. @MarkWitton

FIGURE 3. Skeletal reconstructions showing the majority of the elements preserved in, and relative sizes of, each of the three partial skeletons referred to Mandasuchus tanyauchen, gen. et sp. nov.
A, NHMUK PV R6792; B, NHMUK PV R6793; C, NHMUK PV R6794.

Reconstructions created by Mark Witton. Scale bar equals 1 m.

SYSTEMATIC PALEONTOLOGY

ARCHOSAURIA Cope, 1869–1870

PSEUDOSUCHIA Zittel, 1887–1890

SUCHIA Krebs, 1974

LORICATA Merrem, 1820

MANDASUCHUS TANYAUCHEN, gen. et sp. nov.

‘Ein Saurischier-Rest’ Huene, 1939:65.

‘Mandasuchus longicervix’ Charig, 1956:25, pl. 1–32.

‘Mandasuchus’ Huene, 1956:453.

‘Mandasuchus’ Charig et al., 1956:215.

‘Mandasuchus’ Romer, 1966:368.

‘Mandasuchus tanyauchen’ Charig in Appleby et al., 1967:709.

‘Mandasuchus tanyauchen’ Charig, 1972:131, pl. 3.

‘Mandasuchus’ Sill, 1974:320.

‘Mandasuchus’ Krebs, 1976:75.

‘Mandasuchus tanyauchen’ Krebs, 1976:75.

‘Mandasuchus tanyauchen’ Cruickshank, 1979:170.

‘Mandasuchus’ Parrish, 1993:297.

‘Mandasuchus’ Juul, 1994:6.

‘Mandasuchus’ Gower, 2000:450.

‘Mandasuchus tanyauchen’ Gower, 2000:465.

‘Mandasuchus tanyauchen’ Gower, 2001:121, fig. 1.

‘Mandasuchus tanyauchen’ Thomas, 2004:17, figs. 2.4–2.13, 2.15–2.16, pls. 2.1–2.9.

‘Mandasuchus’ Sen, 2005:188, fig. 9F.

‘Mandasuchus’ de Ricqles et al., 2008:65, table 1, pl. 2.2.

‘Mandasuchus’ Lautenschlager and Desojo, 2011:376.

‘Mandasuchus’ Nesbitt, 2011:9.

‘Mandasuchus tanyauchen’ Nesbitt et al., 2013a:252, table 1, fig. 3.

‘Mandasuchus longicervix’ Nesbitt et al., 2014:1358, 1369.

....

Etymology— Genus name is derived from ‘Manda,’ for the Manda Beds, combined with ‘suchus,’ the Greek term for the Egyptian crocodile-headed god Sobek. The species name is derived from the Greek ‘tany-,’ meaning long, and ‘auchen,’ meaning neck. The genus and species names were created by A. J.C., with the species name intended to reference the elongate neck vertebrae.

Life Reconstruction:  A new life reconstruction, prepared by Mark Witton, is presented here (Fig. 27). The reconstruction is based on the proportions of the largest known specimen (NHMUK PV R6794), and missing body parts (primarily the skull) were based largely on the closely related taxon Prestosuchus.

  

Richard J. Butler, Sterling J. Nesbitt, Alan J. Charig, David J. Gower  and Paul M. Barrett. 2018. Mandasuchus tanyauchen, gen. et sp. nov., A Pseudosuchian Archosaur from the Manda Beds (?Middle Triassic) of Tanzania; pp. 96–121 in Christian A. Sidor and Sterling J. Nesbitt (eds.), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17. Journal of Vertebrate Paleontology. 37(6, Supplement).  DOI:  10.1080/02724634.2017.1343728   

 twitter.com/ButlerLabBham/status/978704743815098368

 twitter.com/MarkWitton/status/978734103636926464
 twitter.com/ButlerLabBham/status/978708279919603712

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

من هنا

او

من هنا

شاهد هذا الفيديو القصير لطريقة التحميل البسيطة

منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات

كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا

شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا

رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا
شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا

تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا

ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.