Search This Blog

مشاركة مميزة

[Ornithology • 2017] Myzomela irianawidodoae • A Colourful New Species of Myzomela Honeyeater from Rote Island in eastern Indonesia ---ScRaBBlE

Myzomela irianawidodoae Prawiradilaga, Baveja, Suparno, Ashari, Ng, Gwee, Verbelen & Rheindt, 2017  photo:   Philippe Verbelen  e-journ...

Translate

Showing posts with label Crocodyliformes. Show all posts
Showing posts with label Crocodyliformes. Show all posts

Wednesday, March 20, 2019

[Paleontology • 2017] Deltasuchus motherali • A Large Neosuchian Crocodyliform from the Upper Cretaceous (Cenomanian) Woodbine Formation of North Texas ---ScRaBBlE


Deltasuchus motherali
Adams, Noto & Drumheller, 2017

ABSTRACT
A new taxon of neosuchian crocodyliform, Deltasuchus motherali, gen. et sp. nov., is described on the basis of a partial skull recovered from the Arlington Archosaur Site within the Upper Cretaceous (Cenomanian) Woodbine Formation of north-central Texas. This productive locality represents a delta plain ecosystem preserving a diverse coastal fauna, including lungfish, turtles, dinosaurs (ornithopods and theropods), and crocodyliforms. Prior to this discovery, the only identified crocodyliforms from the Woodbine Formation had been the longirostrine taxa Terminonaris and Woodbinesuchus. This new taxon is differentiated from other known crocodyliforms by the presence of dual pseudocanines on both the dentary and maxilla; anterior and posterior rami of jugal comparable in depth; anterolaterally facing margin on the dorsal portion of the postorbital; contact between the descending process of the postorbital and the ectopterygoid; and a large, deep fossa on the ventral surface of the quadrate. Phylogenetic analysis recovers D. motherali as the sister taxon to Paluxysuchus newmani from the Lower Cretaceous Twin Mountains Formation of Texas. This clade lies within Neosuchia basal to Goniopholididae + Eusuchia. The associated cranial elements of this new crocodyliform represent a large, broad-snouted individual, an ecomorphotype often associated with the semiaquatic ambush predator niche in this clade, and one not previously reported from the formation.



FIGURE 3. A, articulation of cranial elements of Deltasuchus motherali, gen. et sp. nov., in dorsal view. B, reconstruction of the complete skull of D. motherali. Missing elements in gray, based on Paluxysuchus newmani (Adams, 2013).   Scale bar equals 10 cm.

SYSTEMATIC PALEONTOLOGY

CROCODYLIFORMES Hay, 1930
MESOEUCROCODYLIA Whetstone and Whybrow, 1983
NEOSUCHIA Benton and Clark, 1988

DELTASUCHUS, gen. nov.

Type Species—Deltasuchus motherali, sp. nov.

Etymology—Deltasuchus, ‘Delta’ in reference to the coastal delta plain deposits of the Woodbine Formation in which the new taxon was found; and ‘suchus,’ derived from ‘Souchos,’ the Greek term for the Egyptian crocodile god, Sobek.

DELTASUCHUS MOTHERALI, sp. nov.

Etymology— Deltasuchus motherali, in honor of Austin Motheral, who discovered the type specimen.

Dr. Stephanie Drumheller, Dr. Thomas Adams, and Dr. Chris Noto with the skull of Deltasuchus motherali.

AAS volunteers working to uncover fossils, including those of Deltasuchus, in 2009.


Thomas L. Adams, Christopher R. Noto and Stephanie Drumheller. 2017. A Large Neosuchian Crocodyliform from the Upper Cretaceous (Cenomanian) Woodbine Formation of North Texas. Journal of Vertebrate Paleontology. DOI:   10.1080/02724634.2017.1349776 

---------------------------------------------------------------
روابط التحميل والمشاهدة، الروابط المباشرة للتحميل
او
شاهد هذا الفيديو القصير لطريقة التحميل البسيطة


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] The Earliest Record of Asian Eusuchia from the Lower Cretaceous Khok Kruat Formation of northeastern Thailand ---ScRaBBlE


Fig. 2. Remains of the Ban Saphan Hin crocodyliform from the Khok Kruat Formation,
Ban Saphan Hin, Nakhon Ratchasima Province, Thailand.
A, B, C, Photographs and interpretive drawings of the caudal end of left lower jaw, NRRU4001-33, in lateral (A), dorsal (B), and medial (C) views; D, E, F, Photographs of the fragmentary rostral symphyseal of the right mandible, NRRU4001-29, in medial (D), dorsal (E), and lateral (F) views with the interpretive drawing of dorsal view; G, H, I, J, Photographs of the fragmentary right mandible, NRRU4001-35, in medial (G), dorsal (H), and lateral (I) views with the interpretive drawing of dorsal view and the close up of tooth crown attached to NRRU4001-35 (J); K, L, Photographs of the left postorbital and the anterior end of left squamosal, NRRU4001-36, in the lateral view with the interpretive drawing (K) and the dorsal view (L); M, Photograph of the dorsal view of the osteoderm NRRU4001-19, the white dotted line shows its middle ridge. In interpretive drawings, outlines and sutures were drawn by lines thicker than lines for ridges, shelves and pits and repaired areas were shown by horizontal stripes.

 Scale bars of J, K and L equal 1 cm, all other scale bars equal 5 cm. Abbreviations: ae, anterior edge; an, angular; ar, articular; c, concavity that receives a maxillary tooth; de, dentary; dpa, descending process of articular; fio, foramina for the passage of the nervus intermandibularis oralis; gf, glenoid fossa; lf?, possible lingual foramen; po, postorbital; pof, postorbital foramen; rap, retroarticular process; sa, surangular; sp, splenial; sq, squamosal; tc, isolated tooth crown. 

Abstract
We describe remains of a new crocodyliform found from the Lower Cretaceous (Aptian) Khok Kruat Formation, northeastern Thailand. Remains consist of two caudal ends of mandibles, two rostral symphyseal parts of right rami of mandibles, a dorsal part of postorbital, a cranial end of squamosal and one osteoderm. Phylogenetic analyses supported inclusion of this crocodyliform into the Eusuchia as it shares several morphological characters with other eusuchians, such as a dorsocaudally oriented retroarticular process, smooth lateral surface of the caudoventral region of mandible, and a craniocaudally oriented ridge on the dorsal surface of retroarticular process. The shape of symphyseal region showed this crocodyliform had a longirostrine snout shape, which is uncommon in early eusuchians. Finding of this crocodyliform draws back the oldest record of Asian eusuchians, which was Tadzhikosuchus, approximately 30 million years and it is the only Mesozoic eusuchian found in East and Southeast Asia.

Keywords: Khok Kruat Formation; Aptian; Eusuchia; Thailand; Asia

Systematic paleontology
CROCODYLIFORMES Hay, 1930
MESOEUCROCODYLIA Whetstone and Whybrow, 1983
NEOSUCHIA Clark, 1986
EUSUCHIA Huxley, 1875
gen et sp. indet.

Conclusions: 
 Morphological comparison and phylogenetic analysis showed the Ban Saphan Hin crocodyliform is a member of Eusuchia. But due to its fragmentary nature its phylogenetic position within Eusuchia is currently uncertain. The Ban Saphan Hin crocodyliform indicates longirostrine snout shape evolved during the early stage of eusuchian, which is probably independent from that of gavialoids. Moreover it draws back the oldest record of Asian eusuchians from the Santonian, Tadzhikosuchus found from Tadzhikistan, to the Aptian, approximately 30 million years ( Storrs and Efimov, 2000), and it is the only Mesozoic eusuchian found in East and Southeast Asia. This situation reflects the patchy fossil record of Mesozoic crocodyliform in these areas. The Late Cretaceous crocodyliforms of East Asia were reported only from Mongolia (Storrs and Efimov, 2000; Turner, 2015). Further sampling effort is required to reveal the complex evolutionary history of Asian Mesozoic neosuchians.


Tai Kubo, Masateru Shibata, Wilailuck Naksri, Pratueng Jintasakul and Yoichi Azuma. 2017. The Earliest Record of Asian Eusuchia from the Lower Cretaceous Khok Kruat Formation of northeastern Thailand. Cretaceous Research. In Press. DOI: 10.1016/j.cretres.2017.05.021

---------------------------------------------------------------
روابط التحميل والمشاهدة، الروابط المباشرة للتحميل
او
شاهد هذا الفيديو القصير لطريقة التحميل البسيطة


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] Roxochampsa paulistanus • Reassessment of the Enigmatic Crocodyliform “Goniopholis” paulistanus Roxo, 1936: Historical Approach, Systematic, and Description by New Materials ---ScRaBBlE


 Roxochampsa paulistanus (Roxo, 1936)

Piacentini Pinheiro, Pereira, de Souza, Brum, Lopes, et al., 2018.
exGoniopholis” paulistanus Roxo, 1936:  DOI: 10.1371/journal.pone.0199984 

Abstract
The Crocodyliformes are the most represented vertebrate clade in the Upper Cretaceous sequences of the Bauru Group, Paraná Basin. However, some of the species described have an uncertain taxonomic status and phylogenetic position. For instance, “Goniopholispaulistanus has been assigned as a nomem dubium, due to its description being based on scarce material. The “G”. paulistanus specimens (i.e. teeth and a left tibia) were discovered in two different localities in São Paulo state: Mirandópolis and Valparaíso municipalities; where the upper interval of the Adamantina Formation (Early Maastrichtian of Bauru Group) crops out. Revisiting these specimens, we observed multicrenulated teeth in middle dentary toot- row, a remarkable feature only shared with teleosaurids Machimosaurus hugii (Upper Jurassic of Laurasia) and M. rex (Lower Cretaceous of Tunisia). This apomorphy was also recognized in new material from the Alfredo Marcondes municipality (Presidente Prudente Formation), which are here also referred to “G”. paulistanus. We recognized the teeth of “G.” paulistanus as the lectotype, however the tibia cannot be assigned to a species as it was not collected in association with the teeth. We performed a phylogenetic analysis with a data matrix composed of 388 characters and 86 taxa, analyzed in TNT. The strict consensus tree recovered Neosuchia and Ziphosuchia (Notosuchia + Sebecia) within Mesoeucrocodylia. The species “Gpaulistanus is valid, as a distinct and new genus within Sebecia, in a polytomy with Barreirosuchus, Pepesuchus, Itasuchus and Peirosaurus, forming the clade Itasuchidae. Stolokrosuchus is the sister taxon to Itasuchidae, the sister group of all other Sebecia (Peirosauridae (Mahajangasuchidae + Sebecidae and taxa affinis)). The clades Ziphosuchia, Sebecia and Itasuchidae are here redefined, and we find the last two clades to be more closely related to terrestrial notosuchids than to semiaquatic neosuchians.


Life reconstruction of Roxochampsa paulistanus.
(Illustration by Maurílio Oliveira)

Systematic paleontology

MESOEUCROCODYLIA Whetstone and Whybrow, 1983
ZIPHOSUCHIA modified from Ortega, Gasparini, Buscalioni and Calvo, 2000
SEBECIA modified from Larsson and Sues, 2007
ITASUCHIDAE modified from Carvalho, Ribeiro and Ávilla, 2004

Modified phylogenetic definition: all species closer to Itasuchus jesuinoi than to Barreirosuchus franciscoi, Montealtosuchus arrudacamposi, Mahajangasuchus insignis and Sebecus icaeorhinus (stem-based).

Roxochampsa gen. nov.


Genus etymology: Roxo in honor to an important vertebrate paleontologist from DGM, Mathias de Oliveria Roxo, and the Greek suffix Xαμψαι (Champsai Latinized as ‘‘champsa”) meaning crocodile.

Type species: Roxochampsa paulistanus Roxo, 1936.


Roxochampsa paulistanus (Roxo, 1936) comb. nov.

Basionym: Goniopholis paulistanus Roxo, 1936.

Lectotype: DGM 259-R, an isolated and acute tooth apex.

Paralectotype: DGM 258-R, an isolated and acute tooth apex (wider but lower than DGM 259-R).

Lectotype-paralectotype locality, lithology and horizon: Northwest of São Paulo state, between Três Lagoas (Jupiá old designation) and Araçatuba municipality, collected in a railway section of Noroeste do Brazil Railway. Top of the Adamantina Formation, Upper Cretaceous (Early Maastrichtian) of the Bauru Group, Paraná Basin.

Diagnosis: Roxochampsa paulistanus comb. nov. is a platyrostral notosuchian with an unique set of characters: at least nineteen teeth per hemimandible (eighteen teeth for Itasuchus and Pepesuchus, and at last twenty two for Caririsuchus); festooned dentary formed by two waves, being the first between d4-d5 and the second and more smoothy between d8-d14 (similar feature is shared with the others Itasuchidae species); presence of two alveoli couplets in mid-anterior portion of the mandible (d6/d7 and d8/d9) separated by a small diastema (shared with Itasuchus); splenial well participating in the mandibular symphysis, anteriorly reaching to d5-d6 (shared with Pepesuchus); mandibular symphysis is long, and is as broad as high (shared with Itasuchidae species); last two mandibular teeth sit in an alveolar groove (autapomorphy among Itasuchidae species); interlocking teeth arrangement known as "crocodyloid occlusion" (shared with Itasuchus and Pepesuchus); rostral and mid dentary teeth with apicobasal high relief ridges fully crenulated by pseudo-denticles (autapomorphy among Itasuchidae species).

Fig 2. Geological map of the Bauru Group, Paraná Basin (modified from Paula e Silva et al, 2009]). The outcrops that yielded Itasuchidae specimens is located with the crocodile outlines. A-B and C-D are regional geological sections.

Fig 6. Roxochampsa paulistanus comb. nov. (UFRJ-DG 501-R).
A- lateral view; B- medial view; C- detail, mesio-lingual surface view of tenth hemimandibular tooth; D- detail, lingual surface view of twelfth hemimandibular tooth; E- oclusal view; F- isolate tooth: a- lateral profile; b-lingual view; c- labial view.
Each scale bar = 10 mm. Legend in text.

Fig 7. Roxochampsa paulistanus comb. nov. (UFRJ-DG 451-R).
 A- lateral view; B- medial view; C- oclusal view; D- anterior view; E- posterior view. Each scale bar = 10 mm. Legend in text.


Fig 11. Calibrated strict consensus tree from 225 MLTs (1520 steps, CI = 0.304 and RI = 0.692). The phylogenetic relationships (thin lines) come from the strict consensus tree calibrated with the geological ages (chronostratigraphic chart). Thick lines represents the species temporal range based on specimens occurrence. Also, colors in thick lines represent the inferred habit for studied species.

Fig 12. Hemimandible comparisons between some mesoeucrocodylian taxa.
A- Roxochampsa paulistanus comb. nov. (UFRJ-DG 451-R), right hemimandible fragment; B- Roxochampsa paulistanus comb. nov. (UFRJ-DG 501-R), right hemimandible, lacking the anterior-most portion;
C- Itasuchus jesuinoi (DGM 434-R), left hemimandible fragment mirrored; D- Itasuchus sp. (MUGEO 218-V), right hemimandible fragment;
E- Pepesuchus deiseae (MCT 1788-R), left hemimandible fragment mirrored; F- Machimosaurus buffetauti (SMNS 91415) right hemimandible; G- Goniopholis simus (IPB R359), right hemimandible;
H- Crocodylus niloticus (PV. 6524-R), right hemimandible; I- Caiman latirostris (DGM 156-RR), left hemimandible mirrored, J- Gavialis gangeticus (DGM 289-RR) right hemimandible.
Each scale bar = 10 mm. Legend in text.

Conclusions: 
The enigmatic taxon “Goniopholispaulistanus was reanalyzed in the light of new material collected from the uppermost sequence of the Presidente Prudente Formation in Alfredo Marcondes municipality, Early Maastrichtian, correlated level in the Adamantina Formation first record of Valparaíso and Mirandópolis regions, allowing us to validate the species in a new taxonomic combination Roxochampsa paulistanus. Based on the dubious nature of Goniopholis occurrences in South America, and the disparity in mandibular morphology between Goniopholididae and this species, the new genus Roxochampsa is here proposed.

The new material reveals another tooth morphology present in the Bauru Group, just only verified for Roxochampsa paulistanus and the thalattosuchians teleosaurids: Machimosaurus hugii and M. rex, in which the tooth crown exhibits the main carinae and additionally secondary ones (high relief apicobasal ridges) crenulated by pseudo-denticles. However, the morphological tooth similarities among itasuchids with some neosuchians as goniopholids and some teleosaurids, it reveals a pattern of dental convergence within Mesoeucrocodylia, that lacks a phylogenetic signal.

In our cladistic analysis Roxochampsa paulistanus was recovered in the node Itasuchidae, being closed related to Caririsuchus, Itasuchus, and Pepesuchus. This clade is nested within Sebecia, which is here founded to be the major sister group to Notosuchia, both composing a more inclusive clade Ziphosuchia. Thus, the neocretacic mesoeucrocodylian fauna for South America was formed by terrestrialized and continental semi-aquatic forms from two distinct clades: notosuchians, well-adapted for terrestrial niches (e.g. Uruguaysuchidae, Sphagesauridae, Baurusuchidae), and sebecians as more generic forms that included numerous reversions to an semiaquatic lifestyle (e.g. itasuchids, Stolokrosuchus, Mahajangasuchus and Lorosuchus). In accordance with previous works, we found many homoplastic characters for Crocodyliformes, which could imply a mosaic evolutionary pattern, heavily influenced by the ancestral crocodyliform bauplan.


André E. Piacentini Pinheiro , Paulo Victor Luiz Gomes da Costa Pereira, Rafael G. de Souza, Arthur S. Brum, Ricardo T. Lopes, Alessandra S. Machado, Lílian P. Bergqvist and Felipe M. Simbras. 2018. Reassessment of the Enigmatic Crocodyliform "Goniopholis" paulistanus Roxo, 1936: Historical Approach, Systematic, and Description by New Materials.  PLoS ONE. 13(8): e0199984. DOI: 10.1371/journal.pone.0199984

   

---------------------------------------------------------------
روابط التحميل والمشاهدة، الروابط المباشرة للتحميل
او
شاهد هذا الفيديو القصير لطريقة التحميل البسيطة


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] Magyarosuchus fitosi • A New Large-bodied Thalattosuchian Crocodyliform from the Lower Jurassic (Toarcian) of Hungary, with Further Evidence of the Mosaic Acquisition of Marine Adaptations in Metriorhynchoidea ---ScRaBBlE


Magyarosuchus fitosi 
Ősi​, Young, Galácz & Rabi, 2018


Abstract

Based on associated and three-dimensionally preserved cranial and postcranial remains, a new thalattosuchian crocodyliform, Magyarosuchus fitosi gen. et sp. nov. from the Lower Jurassic (Upper Toarcian) Kisgerecse Marl Formation, Gerecse Mountains, Hungary is described here. Phylogenetic analyses using three different datasets indicate that M. fitosi is the sister taxon of Pelagosaurus typus forming together the basal-most sub-clade of Metriorhynchoidea. With an estimated body length of 4.67–4.83 m M. fitosi is the largest known non-metriorhynchid metriorhynchoid. Besides expanding Early Jurassic thalattosuchian diversity, the new specimen is of great importance since, unlike most contemporaneous estuarine, lagoonal or coastal thalattosuchians, it comes from an ‘ammonitico rosso’ type pelagic deposit of the Mediterranean region of the Tethys. A distal caudal vertebra having an unusually elongate and dorsally projected neural spine implies the presence of at least a rudimentary hypocercal tail fin and a slight ventral displacement of the distal caudal vertebral column in this basal metriorhynchoid. The combination of retaining heavy dorsal and ventral armors and having a slight hypocercal tail is unique, further highlighting the mosaic manner of marine adaptations in Metriorhynchoidea.



Systematic Paleontology

CROCODYLOMORPHA Hay, 1930 (sensu Nesbitt, 2011)
THALATTOSUCHIA Fraas, 1901 (sensu Young & Andrade, 2009)
METRIORHYNCHOIDEA Fitzinger, 1843 (sensu Young & Andrade, 2009)

MAGYAROSUCHUS gen. nov.

Type species—Magyarosuchus fitosi gen. et sp. nov. (type by monotypy).

Etymology— Hungarian crocodile.’ Magyaro referring to the Hungarian people, and suchus is the Latinized form of the Greek soukhos (σoῦχoς), meaning crocodile.


MAGYAROSUCHUS FITOSI, gen. et sp. nov.

Etymology—Fitos’s Hungarian crocodile.’ The name refers to Attila Fitos, discoverer of the specimen in thanks for his donation of the fossil to science.

Type locality—one of the northwestern quarries of the Nagy-Pisznice Hill, close to Békás-canyon, eastern Gerecse Mountains, northwestern Hungary.

Type horizon—Bed 13, Kisgerecse Marl Formation, Transdanubian Central Range. Grammoceras striatulum ammonite Subzone, G. thouarsense ammonite Zone, Upper Toarcian, Lower Jurassic (Galácz et al., 2010).

Diagnosis— Large-sized (estimated body length: in the range of 4.67–4.83 m) metriorhynchoid thalattosuchian with the following unique combination of characters (proposed autapomorphic characters are indicated by an asterisk (*)): tooth crown carinae development variable, being well-developed apically, beginning to develop mid-crown and absent in the basal region; enamel ornamentation is composed of ridges that differ in arrangement on the labial and lingual surfaces, being more widely spaced on the labial surface than the lingual surface, with the lingual surface having tightly packed apicobasal ridges basally which apically become shorter and discontinuous, and the apical lingual ridges on the mesial and distal margins bend towards the carinae (but do not contact them)*; abrupt change in centrum shape of the distal caudal vertebrae, with strong mediolateral compression (i.e. distal vertebrae are clearly heteromorphic); dorsal osteoderms have irregularly shaped pits (including circular, ellipsoid, bean-shaped, triangular and quadrangular shapes), with an extreme variation in size (from small to very large), with elongate pits present on the ventrolateral surface running from the keel to the lateral margin*; dorsal osteoderms have an anterolateral process that is ‘indistinct,’ no longer being distinctly ‘peg-like,’ as their lateral margin is contiguous with that of the osteoderm ventrolateral surface*.



Conclusion: 
Here, we describe a new crocodylomorph taxon, Magyarosuchus fitosi gen. et sp. nov., based on a new skeleton from the Gerecse mountains of Hungary. Despite being incomplete and lacking the cranium, we demonstrate that this late Lower Jurassic taxon shows remarkable similarities with the iconic Lower Jurassic genus Pelagosaurus. Magyarosuchus and Pelagosaurus are found to be sister taxa in all three phylogenetic analyses undertaken herein, although the two characters uniting this arrangement are not known from other basal metriorhynchoids (due to poor preservation of taxa such as Teleidosaurus, Eoneustes and Zoneait). Therefore, we cannot be certain that the sister relationship between Magyarosuchus and Pelagosaurus is natural, or due to incomplete information. Regardless, both are found to be basal metriorhynchoids, near the start of the radiation that yielded dolphin-like crocodyliforms. Interestingly, M. fitosi is the oldest known thalattosuchian discovered from an ‘ammonitico rosso’ type pelagic deposit (rather than the usual estuarine, lagoonal or coastal ecosystems Lower Jurassic thalattosuchians are discovered from). The pelagic depositional environment and neritic associated cephalopod fauna are both consistent with the inferred open-marine adaptation of M. fitosi, namely a mediolaterally compressed distal caudal vertebra with an unusually elongated and dorsally projected neural spine which suggests the presence of a distal tail structure that could have been a hypocercal fin, or a precursor to it. The unique combination of retaining heavy dorsal and ventral armor, while having a slight hypocercal tail, on the other hand, highlights the mosaic manner of marine adaptations in Metriorhynchoidea. Furthermore, it underscores how little is still known about the timing and tempo of metriorhynchoid pelagic adaptations and their early radiation.


Attila Ősi​, Mark T. Young, András Galácz and Márton Rabi. 2018. A New Large-bodied Thalattosuchian Crocodyliform from the Lower Jurassic (Toarcian) of Hungary, with Further Evidence of the Mosaic Acquisition of Marine Adaptations in Metriorhynchoidea.  PeerJ. 6:e4668. DOI: 10.7717/peerj.4668

22 év után derült ki, hogy új faj a gerecsei őskrokodil  hir.press/tech-tudomany/22-ev-utan-derult-ki-hogy-uj-faj-a-gerecsei-oskrokodil/

---------------------------------------------------------------
روابط التحميل والمشاهدة، الروابط المباشرة للتحميل
او
شاهد هذا الفيديو القصير لطريقة التحميل البسيطة


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.

المشاركات الشائعة