[Paleontology • 2018] Phylogenetic Reassessment of Pisanosaurus mertii Casamiquela, 1967, A Basal Dinosauriform from the Late Triassic of Argentina ---ScRaBBlE

Pisanosaurus mertii Casamiquela, 1967

in Agnolín & Rozadilla. 2018. 

Illustration: Gabriel Lio  fosil.cl  ||  DOI: 10.1080/14772019.2017.1352623

Abstract

Pisanosaurus mertii was originally described on the basis of an incomplete skeleton from the early Late Triassic (Carnian) of northern Argentina. It is consistently regarded by most authors as a very basal ornithischian, the sister group of remaining members of the clade. The referral to Ornithischia is based mainly on tooth-bearing bones and tooth morphology. On the other hand, the postcranium is recognized as strikingly plesiomorphic for ornithischians, and even for dinosaurs. The recent description of non-dinosaurian dinosauriforms of the clade Silesauridae having ornithischian-like dentition invites a review of the phylogenetic affinities of Pisanosaurus. In this regard, an overview of the holotype specimen allows a reanalysis of previous anatomical interpretations of this taxon. The phylogenetic analysis presented here suggests that Pisanosaurus may be better interpreted as a member of the non-dinosaurian Silesauridae. It shares with silesaurids reduced denticles on the teeth, teeth fused to maxilla and dentary bone, sacral ribs shared between two sacral vertebrae, lateral side of proximal tibia with a fibular flange, and dorsoventrally flattened pedal ungual phalanges. The present analysis indicates that Pisanosaurus should be removed from the base of the Ornithischia and should no longer be considered the oldest representative of this dinosaurian clade.

Keywords: Pisanosaurus mertii, Ornithischia, Silesauridae, Late Triassic, Argentina

 Comparative silhouette of Pisanosaurus mertii based on available material.
A, modified from Bonaparte (1976); B, present study.

Not to scale. Bones in grey indicate non-preserved elements. 

Federico L. Agnolín and Sebastián Rozadilla. 2018. Phylogenetic Reassessment of Pisanosaurus mertii Casamiquela, 1967, A Basal Dinosauriform from the Late Triassic of Argentina.  Journal of Systematic Palaeontology.  DOI: 10.1080/14772019.2017.1352623

ResearchGate.net/publication/318909984_Phylogenetic_reassessment_of_Pisanosaurus_mertii_Casamiquela_1967_a_basal_dinosauriform_from_the_Late_Triassic_of_Argentina
  Pisanosaurus mertii, no era un dinosaurio ornitisquio at  fosil.cl/pisanosaurus-mertii-2/

 twitter.com/JournalSystPal/status/893463109125451777

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

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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] Pectodens zhenyuensis • A New Diapsid from the Middle Triassic of southern China ---ScRaBBlE

Pectodens zhenyuensis 

Li, Fraser, Rieppel, Zhao & Wang, 2017

   DOI: 10.1017/jpa.2017.12 

Abstract

The Middle and early Late Triassic of southern China is well known for a remarkable diversity of marine vertebrates, particularly reptiles, including an abundance of intriguing new forms (e.g., Jiang et al., 2005; Hu et al., 2011; Li et al., 2016). Here we describe a new diapsid from Yunnan Province. It possesses an elongate neck that exhibits a remarkable similarity to that of many Protorosauria, yet in other respects the skull and postcranium are much less derived.

The new taxon is part of the so-called Panxian-Luoping Fauna and the deposits correspond to the Upper Member of the Guanling Formation, comprising thin to medium bedded, gray to dark-gray laminated marly limestone and limestone, with several layers of bentonite intercalated in the fossil level at Panxian (Wan, 2002; Motani et al., 2008; Jiang et al., 2009). Their age is Pelsonian (middle Anisian, Middle Triassic) as is indicated by the conodont Nicoraella kockeli Zone (Sun et al., 2006; Zhang et al., 2009). A recent U-Pb study indicates the absolute age of these middle Anisian beds to be close to 244 Ma (Wang et al., 2014).

  Life restoration of Pectodens zhenyuensis

by Yu Wang. 

Figure 1: Pectodens zhenyuensis n. gen. n. sp., Photograph of the holotype IVPP V18578. 

Systematic paleontology

Reptilia

Archosauromorpha von Huene, 1946

?Protorosauria Huxley, 1871

Family incertae sedis

Genus Pectodens new genus

Type species: Pectodens zhenyuensis n. gen. n. sp. by monotypy.

Etymology: From the Latin pecto meaning to comb and dens meaning teeth; in reference to the comb-like nature of the marginal dentition.

Occurrence: Luoping County of Yunnan Province, China; Member II of the Guanling Formation, Anisian, Middle Triassic.

Pectodens zhenyuensis new species

Holotype: IVPP V18578. Almost complete articulated skeleton.

Etymology: In honor of Zhenyu Li, who contributed greatly to the collection of the specimen from the field.

....

Conclusions: 

A new, small terrestrial tetrapod is described from the Middle Triassic of Yunnan, China. Pectodens zhenyuensis n. gen. n. sp. bears very characteristic elongate teeth forming a comb-like marginal dentition. The elongate cervicals of Pectodens zhenyuensis n. gen. n. sp. with low neural spines together with the morphology of the cervical ribs are features consistent with protorosaurs, such as Macrocnemus. However, the imperforate puboischiadic plate, simple rounded proximal tarsals, and a straight 5th metatarsal are primitive characteristics. A key protorosaurian character is the long neck with elongated cervical ribs that typically extend across intervertebral articulations. It was mostly on the basis of these characters that Dinocephalosaurus from the Middle Triassic of China was referred to the protorosaurs (Li, 2003). Another long-necked form, Fuyuansaurus, also exhibits certain affinities with protorosaurs, in particular the tanystropheids (Fraser et al., 2013). Yet both taxa also display characters that are inconsistent with at least the tanystropheids. Unlike tanystropheids, but in common with Protorosaurus (personal observation, N.C. Fraser, 2013), both lack a thyroid fenestra in the pelvis.

The Middle Triassic vertebrate faunas of southern China are largely dominated by marine reptiles and fishes, but occasional terrestrial components (e.g., Macrocnemus fuyuanensis) are recovered from localities in the Zhuganpo Member of the Falang Formation (Li et al., 2007; Jiang et al. 2011). Likewise, Pectodens zhenyuensis n. gen. n. sp. exhibits no adaptations for an aquatic lifestyle; instead the long, slender limbs with pronounced articular ends, and elongate digits together with the claw-like distal phalanges speak to an entirely terrestrial existence. No fully terrestrial vertebrates have been documented previously from the Panxian-Luoping Fauna, although the archosaur Qianosuchus mixtus exhibits a combination of terrestrial and aquatic characteristics (Li et al., 2006). Pectodens is therefore the first fully terrestrial reptile reported from the Guanling Formation. The occurrence of terrestrial reptiles such as Macrocnemus and Pectodens are indicative of the proximity of the ancient coastline at the localities where they occur.

Chun Li, Nicholas C. Fraser, Olivier Rieppel, Li-Jun Zhao and Li-Ting Wang. 2017. A New Diapsid from the Middle Triassic of southern China. Journal of Paleontology. 91(6); 1306-1312.   DOI: 10.1017/jpa.2017.12

A new Triassic discovery nms.ac.uk/collections-research/collections-departments/natural-sciences/natural-sciences-news/a-new-triassic-discovery

ivpp.cas.cn/xwdt/tpxw/201801/t20180102_4927332.html

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

من هنا

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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] 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] Aphaneramma gavialimimus • A New Extreme Longirostrine Temnospondyl from the Triassic of Madagascar: Phylogenetic and Palaeobiogeographical Implications for Trematosaurids ---ScRaBBlE

Aphaneramma gavialimimus Fortuny, Gastou, Escuillié, Ranivoharimanana & Steyer, 2017

 DOI: 10.1080/14772019.2017.1335805   Life reconstruction by Marc Boulay | @JournalSystPal 

Aphaneramma gavialimimus

Fortuny, Gastou, Escuillié, Ranivoharimanana & Steyer, 2017

 DOI: 10.1080/14772019.2017.1335805 
  @JournalSystPal 

Abstract

Trematosaurids form a very large and remarkable clade of Triassic tetrapods (Temnospondyli: Stereospondyli) with a worldwide geographical distribution. Compared with specimens from Europe, Australia or North America, they remain relatively scarce in African rocks, where they are mainly known in the Early Triassic of Madagascar and South Africa. Longirostrine trematosaurids were only known from Madagascar, represented by the genus Wantzosaurus. However, we describe herein a new species of the longirostrine trematosaurid Aphaneramma, Aphaneramma gavialimimus sp. nov., from the Olenekian (Lower Triassic) of Madagascar. This genus was previously known from the Early Triassic of Europe and Asia. Based on a new nearly complete skull, the new species is characterized by a premaxilla-nasal suture anteriorly directed, not contacting the nostrils; choanae completely included within the palatines; the ventral opening of the orbits in the anterior part of the interpterygoid vacuities; a very elongated nasal covering more than 50% of the prenarial length; and an anteriorly widened cultriform process. Aphaneramma gavialimimus sp. nov., with a skull length of about 40 cm, may be one of the largest known trematosaurids. Its inclusion in a new phylogenetic analysis confirms its close affinities with the North American genus Cosgriffius, and clarifies the relationships of trematosaurids in general and lonchorhynchines in particular. The new species also increases the palaeobiodiversity of marine trematosaurs in Gondwana and allows discussing their apparently rapid cosmopolitanism just after the great Permian–Triassic mass extinction.

Keywords: Lonchorhynchinae, Olenekian, palaeobiogeography, Permian–Triassic mass extinction

Figure 1. Aphaneramma gavialimimus sp. nov., Lower Triassic of Madagascar in dorsal view. A, photograph of the holotype UAAmb007; B, photograph of the plastotype MNHN-6703; C, interpretative drawing. 

Systematic palaeontology

Temnospondyli Zittel, 1888

Stereospondyli Zittel, 1888

Trematosauria Romer, 1947 sensu Yates & Warren, 2000

Trematosauroidea Säve-Söderbergh, 1935 sensu Schoch, 2013

Family Trematosauridae Watson, 1919

Subfamily Lonchorhynchinae Säve-Söderbergh, 1935 sensu Steyer, 2002

Aphaneramma Smith Woodward, 1904

Type species. Aphaneramma rostratum Smith Woodward, 1904

(D ‘Lonchorhynchus obergi’ Wiman, 1910) from the early Olenekian of the Sticky Keep of Spitsbergen, Vikinghøgda Formation, Svalbard Archipelago, Norway.

Definition. All taxa sharing a more recent common ancestor with Aphaneramma rostratum than with Cosgriffius campi.

Aphaneramma gavialimimus sp. nov. 

 Etymology. Imitates a gharial (Gavialis gangeticus), due to the general shape similarity with this hyper-longirostral taxon.

Aphaneramma gavialimimus sp. nov., Lower Triassic of Madagascar.

 Life reconstruction by Marc Boulay  (MarcBoulay.fr). 

Josep Fortuny, Stéphanie Gastou, François Escuillié, Lovasoa Ranivoharimanana and J.-Sébastien Steyer. 2017. A New Extreme Longirostrine Temnospondyl from the Triassic of Madagascar: Phylogenetic and Palaeobiogeographical Implications for Trematosaurids. Journal of Systematic Palaeontology.   DOI: 10.1080/14772019.2017.1335805  

twitter.com/JournalSystPal/status/881839746095427585

 facebook.com/media/set/?set=a.1824313547882176&type=3

  

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

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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.

[PaleoIchthyology • 2017] Foreyia maxkuhni • Heterochronic Evolution Explains Novel Body Shape in A Triassic Coelacanth from Switzerland ---ScRaBBlE

Foreyia maxkuhni 

Cavin, Mennecart, Obrist, Costeur & Furrer, 2017

  DOI:  10.1038/s41598-017-13796-0 

Abstract

A bizarre latimeriid coelacanth fish from the Middle Triassic of Switzerland shows skeletal features deviating from the uniform anatomy of coelacanths. The new form is closely related to a modern-looking coelacanth found in the same locality and differences between both are attributed to heterochronic evolution. Most of the modified osteological structures in the new coelacanth have their developmental origin in the skull/trunk interface region in the embryo. Change in the expression of developmental patterning genes, specifically the Pax1/9 genes, may explain a rapid evolution at the origin of the new coelacanth. This species broadens the morphological disparity range within the lineage of these ‘living fossils’ and exemplifies a case of rapid heterochronic evolution likely trigged by minor changes in gene expression.

Figure 1: Skeleton of the new coelacanth Foreyia maxkuhni gen. et sp. nov.
(A) Photo and (B) outline of the holotype (PIMUZ A/I 4620). (C) Reconstruction of the whole skeleton.

Sarcopterygii Romer, 1955

Actinistia Cope, 1891

Latimeriidae Berg, 1940 sensu Dutel et al., 20125

Foreyia gen. nov.

Diagnosis: Latimeriid coelacanth with dermal bones covered with numerous large tubercles; hypertrophied otico-occipital portion of skull; fusion of postparietal, supratemporal and extrascapular in postparietal shield, which forms a dome in occipital region; supraorbital sensory canal running in a wide groove; short and curved mandible; pterygopalatine deeper than long with enlarged autopalatine; lachrymojugal and squamosal fused; hypertrophied clavicle; few abdominal vertebrae (seventeen); expanded dorsal and caudal fins; and atrophied pectoral fins.

Foreyia maxkuhni gen. et sp. nov.

Etymology: The generic name honors late Peter L. Forey for his contribution on the study of coelacanth fishes. The specific epithet refers to Max Kuhn, who kindly supported for 12 years the preparation and study of fossils from the Middle Triassic of Graubünden and especially the specimens described here.

Type locality and horizon: Site DF 4 near the Ducanfurgga (Graubünden, Switzerland), upper part of the Prosanto Formation, Middle Triassic (early Ladinian, 240.91 million years ago).

Figure 2: Osteological details of the new coelacanth  Foreyia maxkuhni gen. et sp. nov. (A) Photo and (B) surface CT reconstruction of the skull of the paratype (PIMUZ A/I 4372). (C) Tubercles and denticles in the Holotype (PIMUZ A/I 4620) and (D) in the paratype (PIMUZ A/I 4372).

 1, tubercles on the skull roof. 2, large spine-like tubercles on the posterior margin of the otico-occipital shield. 3, denticles on the fin rays of the first dorsal fin. 4, scales with denticles from the ventral margin of the caudal peduncle. 5, scales with denticles from the anal region. 6, scales with denticles from the belly region. 7, toothed coronoid bones. 8, scales with denticles from the flank. 9, supplementary caudal fin lobe with spiny scales. 10, Scales with denticles from the lobe of the anal fin.

Figure 3: Phylogenetic relationships of  Foreyia maxkuhni gen. et sp. nov. and developmental origin of the derived characters.
(A) Strict consensus trees of the 259 most parsimonious trees of 317 steps (CI = 0.3817, RI = 0.6766) with some of the uniquely derived characters present in Foreyia maxkuhni on the left, and reconstructions of genera with atypical general morphology. (B and C) Shared features of Ticinepomis peyeri and Foreyia maxkuhni (in orange) not included in the cladistics analysis (see main text for numbers). (D) Reconstruction of a coelacanth embryo with localization of embryonic tissues that give rise the derived skeletal features present in Foreyia. It is hypothesized that changes in the expression of Pax9 may have altered the derived characters shown in blue on the reconstruction (E).

All the drawings were made by LC.  Abbreviation: Boc, basioccipital; Cla, clavicle; Exo, exoccipital; lat. Meso., lateral mesoderm; neur. cr., neural crest; pect. f., pectoral fin; S (numbered), somite.

Figure 4: Reconstruction of the living coelacanth  Foreyia maxkuhni gen. et sp. nov.

 Artwork by Alain Bénéteau.

Lionel Cavin, Bastien Mennecart, Christian Obrist, Loïc Costeur and Heinz Furrer. 2017. Heterochronic Evolution Explains Novel Body Shape in A Triassic Coelacanth from Switzerland.  Scientific Reports. 7,  13695.  DOI:  10.1038/s41598-017-13796-0

ResearchGate.net/publication/320533028_Heterochronic_evolution_explains_novel_body_shape_in_a_Triassic_coelacanth_from_Switzerland

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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] Avicranium renestoi • A Bird-like Skull in A Triassic Diapsid Reptile Increases Heterogeneity of the Morphological and Phylogenetic Radiation of Diapsida ---ScRaBBlE

  Avicranium renestoi Pritchard & Nesbitt, 2017

  DOI:10.1098/rsos.170499 

Illustration: Matt Celeskey‏ @clepsydrops 

Abstract

The Triassic Period saw the first appearance of numerous amniote lineages (e.g. Lepidosauria, Archosauria, Mammalia) that defined Mesozoic ecosystems following the end Permian Mass Extinction, as well as the first major morphological diversification of crown-group reptiles. Unfortunately, much of our understanding of this event comes from the record of large-bodied reptiles (total body length > 1 m). Here we present a new species of drepanosaurid (small-bodied, chameleon-like diapsids) from the Upper Triassic Chinle Formation of New Mexico. Using reconstructions of micro-computed tomography data, we reveal the three-dimensional skull osteology of this clade for the first time. The skull presents many archaic anatomical traits unknown in Triassic crown-group reptiles (e.g. absence of bony support for the external ear), whereas other traits (e.g. toothless rostrum, anteriorly directed orbits, inflated endocranium) resemble derived avian theropods. A phylogenetic analysis of Permo-Triassic diapsids supports the hypothesis that drepanosaurs are an archaic lineage that originated in the Permian, far removed from crown-group Reptilia. The phylogenetic position of drepanosaurids indicates the presence of archaic Permian clades among Triassic small reptile assemblages and that morphological convergence produced a remarkably bird-like skull nearly 100 Myr before one is known to have emerged in Theropoda.

KEYWORDS: reptilia, phylogeny, convergence, Permo-Triassic extinction, evolutionary radiation, Triassic

Avicranium renestoi Pritchard & Nesbitt, 2017 

Illustration: Matt Celeskey‏ @clepsydrops 

Figure 2. Line drawing of the restored skull of Avicranium renestoi based on the three-dimensional surface renderings of skull elements in AMNH FARB 30834.

Figure 3. Reconstructed skull of Avicranium renestoi based on rearticulated three-dimensional surface rendering of the skull bones of AMNH FARB 30834.
Callouts include (a) reconstructed endocast in dorsal view, (b) skull roof in dorsal view, (c) postorbital complex (consisting of postfrontal and postorbital) in anterior view, (d) braincase and stapes in posterior view, (e) palatal complex in ventral view, (f) left quadrate in posterior view and (g) braincase and stapes in left lateral view. All bones have been rearticulated based on the facets of the reconstructed elements.

Abbreviations: fb, forebrain; mb, midbrain; pa, parietal; pf, postfrontal; pl, palatine; po, postorbital; pt, pterygoid; qu, quadrate; st, stapes; su, supratemporal. 

Systematic palaeontology

Diapsida

 Drepanosauromorpha 

 Drepanosauridae 

  Avicranium renestoi, n. gen., n. sp.

  Etymology: Avicranium, from aves (Latin for bird) and cranium (Latin for cranium), in reference to the suite of bird-like morphologies present in the holotype skull; renestoi, for Silvio Renesto, who described much of the drepanosauromorph fossil record from Triassic Italy.

  Holotype: AMNH FARB 30834, partial skull and articulated cervical series. Additional drepanosaurid caudal vertebrae and limb fragments are preserved in the block, but are not clearly associated with the individual to which the skull and cervical vertebrae belong.

  Locality: Coelophysis Quarry (‘siltstone member’, Chinle Formation). Recovered during preparation of the holotype block of the shuvosaurid pseudosuchian Effigia okeeffeae by S.J.N. [12].

 Diagnosis: Specimens for anatomical comparisons are listed in appendix C. A drepanosaurid diapsid differing from Hypuronector limnaios, Megalancosaurus preonensis and Vallesaurus cenensis (the only drepanosauromorphs with skull material) in the complete absence of teeth, a dorsoventrally taller retroarticular process with a triangular shape in lateral view, and cervical neural spines with subequal anteroposterior lengths and transverse widths.

Adam C. Pritchard and Sterling J. Nesbitt. 2017. A Bird-like Skull in A Triassic Diapsid Reptile Increases Heterogeneity of the Morphological and Phylogenetic Radiation of Diapsida. ROYAL SOCIETY OPEN SCIENCE.   DOI: 10.1098/rsos.170499 

 twitter.com/PastTimePaleo/status/918164972307349504 et @VTechmeetsPaleo

 twitter.com/clepsydrops/status/918235766165184512

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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.