[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

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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.

[Paleontology • 2018] Semi-aquatic Adaptations in A Spinosaur from the Lower Cretaceous of Brazil ---ScRaBBlE

A Spinosaurinae at the Aptian-Albian lagunar/shallow marine environment of the Romualdo Formation, Araripe Basin, NE Brazil.

in Aureliano, Ghilardi, Buck, et al., 2018. 

DOI: 10.1016/j.cretres.2018.04.024 

Illustration by Julio Lacerda.

Highlights

• Spinosaur histology is here described for the first time.

• Extreme bone compactness (osteosclerosis) was present in Brazilian Spinosaurinae.

• These modifications appeared millions of years before the Moroccan Spinosaurus.

• One of the largest spinosaur specimens from the Early Cretaceous of South America.

Abstract

Spinosaurinae are known to have a strong relationship with aquatic environments, involving several anatomical adaptations. Nonetheless, this group of theropods remains enigmatic, due to the relative incompleteness of its fossil record. A large partial tibia from the Aptian-Albian Romualdo Formation, Northeast Brazil, is herein described through anatomical comparisons and paleohistological analyzes. It features characteristics previously only observed in Spinosaurus aegyptiacus, which includes a reduced fibular crest and an osteosclerotic condition. The later, a character supported as correlated with semi-aquatic habits in many limbed vertebrates. The results presented here support high bone compactness being already present in Brazilian Spinosaurinae millions of years before the Moroccan Spinosaurus. Furthermore, histological analyses demonstrate the Romualdo Formation specimen was a young subadult still growing fast by the time of its death, and suggests Araripe Basin Spinosaurinae could have grown larger than previously thought. This work contributes to a better paleobiological and ecological understanding of South American spinosaurs, and helps fill a gap in the macroevolutionary comprehension of Spinosaurinae. Ultimately, it also contributes to further advancing the paleoecological characterization of the Romualdo Formation.

Keywords: Paleohistology; Araripe basin; Theropoda; Megalosauroidea; Spinosaurinae

Systematic paleontology

Dinosauria Owen, 1842

Theropoda Marsh, 1882

Tetanurae Gauthier, 1986

Megalosauroidea Fitzinger, 1843

Spinosauridae Stromer 1915

Spinosaurinae Stromer, 1915

gen. et. sp. indet.

Referred material: LPP-PV-0042, a fragmentary tibia.

Locality and horizon: Exact geological and geographical provenance is unknown, but the fossil was collected in the Araripe area, Northeast Brazil. Outcrops of the Lower Cretaceous Santana Group (Araripe Basin) are worldwide known for providing well-preserved fossils and are located in the Araripe region. 

Fig. 6. 1. Spinosaurinae remains currently recovered from the Romualdo Formation, Araripe Basin, Brazil. Not to scale.
 A, USP GP/2T-5, holotype of Angaturama limai ( Kellner & Campos, 1996), fragmentary anterior tip of skull.
B, SMNS 58022, holotype of Irritator challengeri (Sues et al., 2002) (originally mistakenly identified as a maniraptor by Martill et al., 1996), partial posterior portion of skull and mandible.
C, MN 4743-V, incomplete indeterminate spinosaur sacral and caudal vertebrae series (S3, S4, S5, C1, C2. C3, C4, C4, C6) (Bittencourt & Kellner, 2004).
D, MN 7021-V, indeterminate spinosaur rib (Machado & Kellner, 2007). E, MN4819-V, incomplete indeterminate spinosaur pubis, pelvis, dorsal, sacral and caudal vertebrae (d, S1, S2, S3, S4, S5, C1), incomplete indeterminate spinosaur right manus, fragmentary right tibia and femur ( Machado et al., 2008; Machado and Kellner, 2009 ; Machado, 2010).
 F, LPP-PV-0042, Spinosaurinae indet. metaphysis of left tibia described in this work. Skeletal reconstruction made by Tito Aureliano, based on the work by Scott Hartman and Marcos Sales. 

2. Romualdo Spinosaurinae specimens to scale. A, Angaturama USP GP/2T (∼8.3 m, on the reconstruction by Sales & Schultz, 2017). B, Irritator SMNS 58022 (∼6.5 m, from the reconstruction by Sales & Schultz, 2017). C, Spinosaurinae indet. MN4819-V (∼5.9 m; Machado et al., 2008). D, Spinosaurinae indet. LPP-PV-0042 (∼10 m; this work). Scale bar in 7.2 is 1 m. 

Fig. 8. Reconstruction of a Spinosaurinae at the Aptian-Albian lagunar/shallow marine environment of the Romualdo Formation, Araripe Basin, NE Brazil. 

Illustration by Julio Lacerda.

Fig. 7. Inferred food web of the Aptian-Albian Romualdo Formation, Northeast Brazil. Vertebrate silhouettes are highlighted in black. Trophic relations are represented by arrows, of which solid bold red represent ecological interactions with direct fossil evidence from Romualdo Formation; solid black indicate putative trophic interactions with general theoretical support; and dashed grey represent weak or uncertain but plausible trophic links.
1, Spinosaurinae; 2, small to medium sized terrestrial theropods; 3, pterosaurs; 4, semi-aquatic crocodyliforms; 5, terrestrial omnivorous crocodyliforms; 6, semi-aquatic chelonians; 7, large fishes; 8, small fishes; 9, plants; 10, macroinvertebrates; 11, plankton. See Text S1 in the Supplementary material for list of references. Spinosaurinae silhouette by Tito Aureliano. Other silhouettes from Phylopic (http://phylopic.org/), courtesy of Almandine (vectorized by T. Michael Keesey), FunkMonk (adapted), Hans Hillewaert, John Conway, Melissa Broussard, Nobu Tamura (vectorized by T. Michael Keesey), Olegivvit, Robert Gay and Sergio A. Muñoz-Gómez.  

Conclusion: 

The Romualdo Formation specimen LPP-PV-0042 comprises a fragmentary tibia with a reduced fibular crest and osteosclerotic histology previously only observed in Spinosaurus aegyptiacus, supporting that this unique feature was already present in Brazilian Spinosaurinae (basal Spinosaurinae) during the Aptian-Albian time, at least 10 myr before the Moroccan Spinosaurus.

Histological analyses suggest LPP-PV-0042 was a young, fast growing subadult and also that the bone microstructure varies a lot across the cross-section, probably due to areas of muscle insertion. The latter observation suggests that caution is needed when describing bone histology of dinosaurs, since only one slice from the shaft is not always representative of the entire histology of the bone.

Furthermore, the current specimen represents one of the largest spinosaurs from this unit so far (∼10 m in reconstructed TL). It was larger than the Irritator holotype and possibly larger than Angaturama holotype as well. Considering the subadult status inferred from its histology, the referred individual would have grown even larger.

The Romualdo paleoenvironment could support large predators with semi-aquatic habits due to its high productivity and diversity of aquatic species as an ecotone. Spinosaurinae from Romualdo Formation probable occupied the position of apex predators different.

Thus, the skeletal element LPP-PV-0042 from the Romualdo Formation, although fragmentary, has provided much information about Brazilian Spinosaurinae paleobiology and ecology. Moreover, it gives new insight into the evolution of semi-aquatic adaptations in this group, revealing the need to investigate other taxa within the clade and expand the search for more spinosaur fossils.

  

Tito Aureliano, Aline M. Ghilardi, Pedro V. Buck, Matteo Fabbri, Adun Samathi, Rafael Delcourt, Marcelo A. Fernandes and Martin Sander. 2018. Semi-aquatic Adaptations in A Spinosaur from the Lower Cretaceous of Brazil. Cretaceous Research. In Press.  DOI: 10.1016/j.cretres.2018.04.024

 twitter.com/AlineGhilardi/status/992177606933000192

 twitter.com/AlineGhilardi/status/992152367633240065

Dense Bones and Other Aquatic Adaptations in Spinosaurs  https://blog.everythingdinosaur.co.uk/blog/_archives/2018/05/06/dense-bones-and-other-aquatic-adaptations-in-spinosaurs.html

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

من هنا

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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] Titanosaur Dinosaurs from the Upper Cretaceous of La Rioja Province, NW Argentina ---ScRaBBlE

Titanosaur dinosaurs were found in two Upper Cretaceous units of La Rioja, Argentina.

in Hechenleitner, Fiorelli, Martinelli & Grellet-Tinner, 2018.

DOI: 10.1016/j.cretres.2018.01.006 

Highlights

• Titanosaur dinosaurs were found in two Upper Cretaceous units of La Rioja, Argentina.

• Most of the specimens are interpreted as non-Saltasaurinae lithostrotians.

• Few bones (caudal vertebrae) show features consistent with pathology.

• Differences in caudal vertebrae suggest the presence of at least two taxa.

Abstract

Our current knowledge of Argentinean titanosaurs outside Patagonia has been effectively limited to the province of Salta (e.g., Saltasaurus). However, several skeletal remains of titanosaurian sauropod dinosaurs have been discovered in the Cretaceous strata of La Rioja Province, northwest Argentina. Herein we describe new titanosaur material from two Upper Cretaceous localities from La Rioja. The first record corresponds to two caudal vertebrae found in the exposures of the Ciénaga del Río Huaco Formation, in the Quebrada de Santo Domingo locality. The largest sample, which includes fragmentary postcranial material of five individuals, was recovered from the Los Llanos Formation, in the Tama locality. The comparative analyses conducted here suggest that most of the specimens should be referred to as Lithostrotia non Saltasaurinae. However, differences between the middle caudal vertebrae from Tama and Quebrada de Santo Domingo suggest that the taxa at each locality are distinct.

Keywords: Los Llanos Formation; Cienaga del Rio Huaco Formation; Tama; Quebrada de Santo Domingo; Sauropods

Systematic paleontology

Saurischia Seeley, 1888

Sauropodomorpha Huene, 1932

Sauropoda Marsh, 1878

Titanosauria Bonaparte and Coria, 1993

Lithostrotia Upchurch, Barrett and Dodson, 2004

Lithostrotia gen. et sp. indet. 1

Material. CRILAR-Pv 518a-i, nine partial caudal vertebrae.

.....

Conclusions: 

The sauropod specimens described from La Rioja province herein are all referred to Titanosauria. CRILAR-Pv 518 (nine caudal vertebrae) can be identified as a non-saltasaurine lithostrotian, as it presents strongly procoelous centra in its anterior and middle caudal vertebrae, a synapomorphy of Lithostrotia (Upchurch et al., 2004). In addition the centra are almost as high as wide, instead of dorsoventrally compressed as is typical in Saltasaurinae.

The information provided by the few appendicular elements of the specimen CRILAR-Pv 509 suggests that it could be also considered as a non-saltasaurine lithostrotian, as it shows remarkable similarities to Aeolosaurus, Uberabatitan and Bonitasaura, such as the pubis being elongate and only slightly recurved, differing from Saltasaurinae, and the condylar surfaces of the distal end of the femur are perpendicular to its major axis rather than “beveled”.

The specimens CRILAR-Pv 510 and 511 are fragmentary and not particularly diagnostic. However, the procoely of the small centrum of the caudal vertebra CRILAR-Pv 510, as well as its proportions, suggest titanosaur affinities. Considering the taxa represented in the Los Llanos Formation, the ilium CRILAR-Pv 511 has a relative size and a series of characters (such as the lateral expansion preacetabular crest, and the extensive and continuous union between the pubic peduncle and the preacetabular crest), which could only be consistent with the morphology of the Titanosauria.

The poor preservation of the specimen CRILAR-Pv 525 obscures a clear diagnosis but the evidence suggests that its anomalous structures have a pathological origin. Both the presence of bony overgrowth and draining channels (subperiosteal pits) suggest that the origin of this condition was a response to an infection. This constitutes an additional paleopathological record for titanosaurs, which were unreported until recently.

With respect to their diversity, the fragmentary condition of all the specimens of Tama prevents comparison between individuals. Therefore, there is no reason presently to infer the occurrence of more than one taxon in this locality. However, the strong curvature (in lateral view) of the ventral edge of the vertebral centra of Quebrada de Santo Domingo clearly contrasts with the almost flat condition observed in the Tama specimen, suggesting the presence of distinct taxa in each locality.+

E. Martín Hechenleitner, Lucas E. Fiorelli, Agustín G. Martinelli and Gerald Grellet-Tinner. 2018. Titanosaur Dinosaurs from the Upper Cretaceous of La Rioja Province, NW Argentina. Cretaceous Research. 85; 42–59.  DOI: 10.1016/j.cretres.2018.01.006

   

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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.