[PaleoMammalogy • 2017] New Records of the Dolphin Albertocetus meffordorum (Odontoceti: Xenorophidae) from the lower Oligocene of South Carolina: Encephalization, Sensory Anatomy, Postcranial Morphology, and Ontogeny of early Odontocetes ---ScRaBBlE

Albertocetus meffordorum   Uhen, 2008 

Boessenecker, Ahmed & Geisler, 2017

DOI: 10.1371/journal.pone.0186476 

Abstract

We report five new specimens of xenorophid dolphins from North and South Carolina. Four of the specimens represent the xenorophid Albertocetus meffordorum, previously only known from the holotype skull. The other is a fragmentary petrosal from the upper Oligocene Belgrade Formation that we refer to Echovenator sp, indicating at least two xenorophids from that unit. Two of the Albertocetus meffordorum specimens are from the lower Oligocene Ashley Formation: 1) a partial skeleton with neurocranium, fragmentary mandible, ribs, vertebrae, and chevrons, and 2) an isolated braincase. The partial vertebral column indicates that Albertocetus retained the ancestral morphology and locomotory capabilities of basilosaurid archaeocetes, toothed mysticetes, and physeteroids, and caudal vertebrae that are as wide as tall suggest that the caudal peduncle, which occurs in all extant Cetacea, was either wide or lacking. CT data from the isolated braincase were used to generate a digital endocast of the cranial cavity. The estimated EQ of this specimen is relatively high for an Oligocene odontocete, and other aspects of the brain, such as its anteroposterior length and relative size of the temporal lobe, are intermediate in morphology between those of extant cetaceans and terrestrial artiodactyls. Ethmoturbinals are also preserved, and are similar in morphology and number to those described for the Miocene odontocete Squalodon. These fossils extend the temporal range of Albertocetus meffordorum into the early Oligocene, its geographic range into South Carolina, and expand our paleobiological understanding of the Xenorophidae.

Fig 1. Locality map of occurrences of Albertocetus meffordorum in North and South Carolina. (A) and a geologic map of Charleston, South Carolina (B), skeletal reconstruction of Albertocetus meffordorum with preserved elements in red (C), generalized stratigraphy at Belgrade Quarry (D)  and generalized Paleogene stratigraphy of the Charleston area (E). Gray in geologic map denotes Ashley Formation and black denotes Chandler Bridge Formation. 

Systematic paleontology

Cetacea Brisson, 1762

Pelagiceti Uhen, 2008

Odontoceti Flower, 1867

Xenorophidae Uhen, 2008

Albertocetus Uhen, 2008

Albertocetus meffordorum Uhen, 2008

.....

Conclusions

1. New odontocete specimens from the lower Oligocene Ashley Formation of South Carolina include an isolated cranium and a partial skeleton including incomplete cranium with petrotympanics and fragmentary mandible, cervical, thoracic, lumbar, and caudal vertebrae, ribs, and a chevron. These specimens extend the range of Albertocetus meffordorum into the early Oligocene.

2. Well-preserved petrosals permit more refined identification of a recently reported petrosal from the upper Oligocene Belgrade Formation of North Carolina as Echovenator sp., and permit referral of two additional Belgrade Formation petrosals to Albertocetus meffordorum and Echovenator sp. Future collecting efforts in North Carolina are expected to yield other cetaceans conspecific with those from the contemporaneous Chandler Bridge Formation of South Carolina.

3. The endocast of Albertocetus meffordorum is intermediate in morphology between extant odontocetes and archaeocete whales. Endocast volume indicates that Albertocetus meffordorum is the most highly encephalized odontocete from the early Oligocene (EQ = 2.586), well within the range of extant delphinoids, and chronicling a drastic jump in EQ across the Eocene-Oligocene boundary. Further study of appropriate body size estimation is needed to investigate the proposed Eocene-Oligocene explosion in odontocete encephalization.

4. The sample size of Albertocetus meffordorum permits the first basic examination of ontogenetic trends in stem Odontoceti. Ontogenetic study of Albertocetus meffordorum identifies several sutures of the dorsal braincase and facial region of interest for assessing ontogenetic status in stem Odontoceti (e.g. median parietal suture, frontoparietal suture, frontonasal suture, parieto-occipital suture), to be confirmed with larger samples of undescribed xenorophids (e.g. Echovenator, Xenorophus). Postcranial epiphyseal fusion is achieved earlier in ontogeny than cranial suture closure in A. meffordorum.

5. Vertebral proportions indicate that Albertocetus meffordorum, like basilosaurids, Mysticeti, and sperm whales, is a "pattern 1" species with no anteroposterior specialization of the vertebral column. This indicates that dorsoventral undulation occurred through the entire flexible lumbocaudal series; this appears to characterize stem odontocetes. Rectangular caudal vertebrae indicate the presence of caudal flukes. Surprisingly, no caudal vertebrae are transversely narrower than tall, suggesting the absence of a transversely narrowed peduncle as in all extant Mysticeti and Odontoceti. Such a feature would imply that the narrow peduncle evolved independently. However, skeletons of stem odontocetes and mysticetes with a more complete caudal series are required to further evaluate this hypothesis.

Robert W. Boessenecker,  Erum Ahmed and  Jonathan H. Geisler. 2017. New Records of the Dolphin Albertocetus meffordorum (Odontoceti: Xenorophidae) from the lower Oligocene of South Carolina: Encephalization, Sensory Anatomy, Postcranial Morphology, and Ontogeny of early Odontocetes. PLoS ONE. 12(11); e0186476.  DOI: 10.1371/journal.pone.0186476

New postcranial skeleton of ancient dolphin Albertocetus meffordum found in South Carolina  phy.so/429369468 via @physorg_com

 blogs.cofc.edu/macebrownmuseum/2017/11/10/friday-fossil-feature-4-specimens-are-dolphinately-better-than-1/

 blogs.plos.org/paleocomm/2017/11/08/author-interview-bobby-boessenecker-on-albertocetus

 twitter.com/CoastalPaleo/status/928396997735993345

 twitter.com/tetrameryx/status/929095659667492870
Fossils in @CofCNatHistory collections @CofC

  

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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] Premaxillary Crest Variation within the Wukongopteridae (Reptilia, Pterosauria) and Comments on Cranial Structures in Pterosaurs ---ScRaBBlE

Figure 1: The variation of cranial crest within the Wukongopteridae.
Kunpengopterus sinensis (IVPP V 16047), (a) complete skull and (b) close-up of the area in the white frame of a, showing the flat crestless skull roof;
holotype of Darwinopterus linglongtaensis (IVPP V 16049), (c) complete skull and (d) close-up of the area in the white frame of c; new specimen (IVPP V 17957), (e) complete skull (inverted), and (f) close-up of the area in the white frame of e; IVPP V 17959 (g) complete skull (inverted), and (h) close-up of the area in the white frame of g, with arrow 1 pointing at the low premaxillary crest and arrow 2 pointing at the crestless middle portion of the premaxilla;
Darwinopterus robustodens (holotype, HGM 41HIII-0309A) (i) complete skull based on Lü et al. 2011b), and (j) close-up of the area in the white frame of i.

Scale bar: 50mm in a, c, e, g, i; 10mm in b, d, f, h, j. 

Cheng, Jiang, Wang & Kellner, 2017.   DOI: 10.1590/0001-3765201720160742 

ABSTRACT

Cranial crests show considerable variation within the Pterosauria, a group of flying reptiles that developed powered flight. This includes the Wukongopteridae, a clade of non-pterodactyloids, where the presence or absence of such head structures, allied with variation in the pelvic canal, have been regarded as evidence for sexual dimorphism. Here we discuss the cranial crest variation within wukongopterids and briefly report on a new specimen (IVPP V 17957). We also show that there is no significant variation in the anatomy of the pelvis of crested and crestless specimens. We further revisit the discussion regarding the function of cranial structures in pterosaurs and argue that they cannot be dismissed a priori as a valuable tool for species recognition.

Key words: Wukongopteridae; Pterosauria; cranial crest; sexual dimorphism; China

.....

CONCLUSION: 

The function of cranial crests in pterosaurs will be a matter of contempt until more material becomes available. Although the comparisons of the pelvic elements of wukongopterids is interesting, one cannot overemphasize the reduced number of specimens on which this and other studies are based. Variations introduced by taphonomy, allied with morphological differences as a result of ontogeny and other factors cannot be adequately assessed with three or so individuals. Notwithstanding these shortcomings, the explanation of the evolutionary function of cranial crests as sexual dimorphism (including mutual sexual selection, Hone et al. 2012) should not be used as the default option. As has been pointed out before (e.g., Kellner and Campos 2002a, 2002b), it seems quite unlikely that once a pterosaur developed a cranial crest (as perhaps the so called “bizarre structures” in other reptiles), this structure could not have performed a variety of functions. Despite the limitation of the available data, it seems difficult not to acknowledge that these quite distinct anatomical features have played a major role in species recognition, as has been put forward for other reptiles (e.g., Padian and Horner 2011). This has been shown to be true at least for some material of the Pteranodon-complex and seems also to have been the case for the Wukongopteridae. Perhaps more detailed studies of deposits with large amount of specimens that might have been part of the same or closely related populations like the occurrences of Caiuajara dobruskii and Hamipterus tianshanensis (and others that might come to light) have the potential to provide a step further into the discussion of several paleobiological questions concerning flying reptiles, including sexual dimorphism and ontogeny (Kellner 2015). Meanwhile the variation in shapes and sizes of cranial crests that are found in pterosaurs, associated with other morphological features, should not be understated as being a powerful tool for understanding their diversity.

  Xin Cheng, Shunxing Jiang, Xiaolin Wang and Alexander W. A. Kellner. 2017. Premaxillary Crest Variation within the Wukongopteridae (Reptilia, Pterosauria) and Comments on Cranial Structures in Pterosaurs. Anais da Academia Brasileira de Ciências. [An. Acad. Bras. Ciênc.] 89(1); Epub Feb 09, 2017.  DOI: 10.1590/0001-3765201720160742 

ResearchGate.net/publication/313538541_Premaxillary_crest_variation_within_the_Wukongopteridae_Reptilia_Pterosauria_and_comments_on_cranial_structures_in_pterosaurs

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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.

[Herpetology • 2017] An Ontogenetically Stable Sexual Character in A Montane Agamid, Salea horsfieldii Gray, 1845 (Reptilia: Agamidae) from Nilgiris, India ---ScRaBBlE

Figure 1. Dimorphic secondary sexual ornamentation in different size classes of Salea horsfieldii.
 Insets a, b, c and d are females of SVL 28.6 mm, 36.2 mm, 57.2 mm and 71.4 mm, respectively, and 
e, f, g and h are males of SVL 29.08 mm, 40.6 mm, 67.4 mm and 74.7 mm, respectively.
 The red arrow mark shows the break at the nuchal region in males.

Daniel , Sreekar & Deepak, 2017

 DOI: 10.1080/00222933.2017.1369188

ABSTRACT

Many agamid lizards are known to show sexual dimorphism in body shape, colour and ornamentation or a combination of these traits. Adult males of Salea horsfieldii have a discontinuous dorsal crest at the nuchal region, which is a sexually dimorphic character. However, there is no information about the age or size at which this dimorphic ornamentation develops and if the species exhibits sexual shape dimorphism (SShD). The authors studied the morphology of S. horsfieldii and found that its ornamentation is an ontogenetically stable character present in all males, including juveniles. Seven morphological characters were measured to determine if they exhibited SShD at adult and juvenile stages. Analysis of covariance was used to identify differences in morphology between sexes. The results show that only adults exhibited SShD, but not juveniles. Adult males had larger head and foot lengths in comparison to females of the same size. Larger head length in adult males is a sexual fitness trait, which increases bite-force during intra-sexual combats. Although the presence of sexually dimorphic ornamentation right from the juvenile stage is rare in agamids, S. horsfieldii is an exception . The role of sexually dimorphic ornamentation at juvenile stages remains unknown and requires further investigation.

KEYWORDS: Lizard, ontogeny, ornament, Salea, sexual dimorphism

Caleb Daniel G., Rachakonda Sreekar and V. Deepak. 2017. An Ontogenetically Stable Sexual Character in A Montane Agamid, Salea horsfieldii Gray, 1845 (Reptilia: Agamidae) from Nilgiris, India. Journal of Natural History. DOI: 10.1080/00222933.2017.1369188

ResearchGate.net/publication/319551820_An_ontogenetically_stable_sexual_character_in_a_montane_agamid_Salea_horsfieldii_Gray_1845_Reptilia_Agamidae_from_Nilgiris_India

  

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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] Anhanguera Taxonomy Revisited: Is Our Understanding of Santana Group Pterosaur Diversity Biased by Poor Biological and Stratigraphic Control? ---ScRaBBlE

Figure 2: Specimen AMNH 22555, a partial anhanguerid skeleton.
Some selected elements are figured in detail. (A) pelvic region in dorsal view; (B) torso in dorsal view; (C, D, E) sixth cervical vertebrae in, respectively, anterior, dorsal and right lateral views; (F, G) right mandibular ramus in, respectively, medial and lateral views; (H) left scapula in dorsal view; (I) left coracoid in lateral view; (J) distal carpals in distal view; (K) proximal carpals in distal view.

Scale bars equal to 50 mm. Line drawings of some bones were modified from Witton (2013).DOI: 10.7717/peerj.3285 

Abstract

Background

Anhanguerids comprise an important clade of pterosaurs, mostly known from dozens of three-dimensionally preserved specimens recovered from the Lower Cretaceous Romualdo Formation (northeastern Brazil). They are remarkably diverse in this sedimentary unit, with eight named species, six of them belonging to the genus Anhanguera. However, such diversity is likely overestimated, as these species have been historically diagnosed based on subtle differences, mainly based on the shape and position of the cranial crest. In spite of that, recently discovered pterosaur taxa represented by large numbers of individuals, including juveniles and adults, as well as presumed males and females, have crests of sizes and shapes that are either ontogenetically variable or sexually dimorphic.

Methods

We describe in detail the skull of one of the most complete specimens referred to Anhanguera, AMNH 22555, and use it as a case study to review the diversity of anhanguerids from the Romualdo Formation. In order to accomplish that, a geometric morphometric analysis was performed to assess size-dependent characters with respect to the premaxillary crest in the 12 most complete skulls bearing crests that are referred in, or related to, this clade, almost all of them analyzed first hand.

Results

Geometric morphometric regression of shape on centroid size was highly statistically significant (p = 0.0091) and showed that allometry accounts for 25.7% of total shape variation between skulls of different centroid sizes. Premaxillary crests are both taller and anteroposteriorly longer in larger skulls, a feature consistent with ontogenetic growth. A new diagnosis is proposed for Anhanguera, including traits that are nowadays known to be widespread within the genus, as well as ontogenetic changes. AMNH 22555 cannot be referred to “Anhanguera santanae” and, in fact, “Anhanguera santanae”, “Anhanguera araripensis”, and “Anhanguera robustus” are here considered nomina dubia.

Discussion

Historically, minor differences in crest morphology have been used in the definition of new anhanguerid species. Nowadays, this practice resulted in a considerable difficulty in referring well-preserved skulls into known taxa. When several specimens are analyzed, morphologies previously believed to be disparate are, in fact, separated by a continuum, and are thus better explained as individual or temporal variations. Stratigraphically controlled excavations on the Romualdo Formation have showed evidence for faunal turnover regarding fish communities. It is thus possible that some of the pterosaurs from this unit were not coeval, and might even represent anagenetic morphotypes. Unfortunately, amateur collecting of Romualdo Formation fossils, aimed especially at commerce, resulted in the lack of stratigraphic data of virtually all its pterosaurs and precludes testing of these further hypotheses.

Felipe L. Pinheiro​ and Taissa Rodrigues. 2017. Anhanguera Taxonomy Revisited: Is Our Understanding of Santana Group Pterosaur Diversity Biased by Poor Biological and Stratigraphic Control? PeerJ. 5:e3285.  DOI: 10.7717/peerj.3285 

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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] The Smallest Diplodocid Skull Reveals Cranial Ontogeny and Growth-Related Dietary Changes in the Largest Dinosaurs ---ScRaBBlE

Life reconstruction of CMC VP14128. Note the cranial morphologies interpreted to denote differing feeding strategies: in CMC VP14128 the narrow snout with posteriorly elongated and morphologically varied tooth row for bulk feeding vs. the widened snout with anteriorly restricted peg-shaped teeth for ground-level browsing in adults. Also note the camouflaged ontogenetic color change suggesting young diplodocids may have sought forested refuge.

in Woodruff, Carr, Storrs, et al., 2018. 

 DOI:  10.1038/s41598-018-32620-x  

Reconstruction by A. Atuchin.

Abstract

Sauropod dinosaurs were the largest terrestrial vertebrates; yet despite a robust global fossil record, the paucity of cranial remains complicates attempts to understand their paleobiology. An assemblage of small diplodocid sauropods from the Upper Jurassic Morrison Formation of Montana, USA, has produced the smallest diplodocid skull yet discovered. The ~24 cm long skull is referred to cf. Diplodocus based on the presence of several cranial and vertebral characters. This specimen enhances known features of early diplodocid ontogeny including a short snout with narrow-crowned teeth limited to the anterior portion of the jaws and more spatulate teeth posteriorly. The combination of size plus basal and derived character expression seen here further emphasizes caution when naming new taxa displaying the same, as these may be indicative of immaturity. This young diplodocid reveals that cranial modifications occurred throughout growth, providing evidence for ontogenetic dietary partitioning and recapitulation of ancestral morphologies.

Figure 1: Skeletal reconstruction of CMC VP14128 to scale with a mature Diplodocus carnegii (dark grey). Grey bones are missing, while those in ivory are those present in CMC VP14128. Skeletal reconstruction based on the Diplodocus by S. Hartman. Silhouettes by S. Hartman and PhyloPic (Creative Commons Attribution-ShareAlike 3.0 Unported; phylopic.org; creativecommons.org), modifications made. Skeletal reconstruction of CMC VP14128 redrawn from D. carnegii skeletal by S. Hartman (skeletaldrawing.com). Human scale is Andrew Carnegie at his natural height of 1.6 m. Skeletal and silhouettes to scale. (B) CMC VP14128 in right lateral view with accompanying schematic. (C) CMC VP14128 in left lateral view with accompanying schematic. Schematics by DCW. The four portions of the skull numbered on accompanying schematics.

 Lateral views and schematics to scale. a: angular, al: alisphenoid, aof: antorbital fenestra, d: dentary, f: frontal, h: hyoid, l: lacrimal, m: maxilla, n: nasal, oc: occipital condyle, os: orbitosphenoid, p: parietal, paof: preantorbital fenestra, pf: prefrontal, pm: premaxilla, po: postorbital, pro: prootic, q: quadrate, sa: surangular, sq: squamosal. L and r before bone denotes if it is left or right.

Systematic Paleontology

Saurischia Seeley 1887

Sauropodomorpha von Huene 1932

Sauropoda Marsh 1878

Diplodocoidea Marsh 1884

Flagellicaudata Harris and Dodson 2004

Diplodocidae Marsh 1884

cf. Diplodocus Marsh 1878.

....

Figure 5: Life reconstruction of CMC VP14128. Note the cranial morphologies interpreted to denote differing feeding strategies: in CMC VP14128 the narrow snout with posteriorly elongated and morphologically varied tooth row for bulk feeding vs. the widened snout with anteriorly restricted peg-shaped teeth for ground-level browsing in adults. Also note the camouflaged ontogenetic color change suggesting young diplodocids may have sought forested refuge. Reconstruction by A. Atuchin.

Conclusions: 

Within Dinosauria, there are small bodied taxa that display basal and derived characters and occupy unusual basal phylogenetic positions. The validity and position of such taxa has been disputed, and regarding sauropodomorph phylogeny, we would advocate that the combination of basal and derived characters and basal phylogenetic recovery should be recognized as an indicator of an immature ontogimorph – instead of a distinct taxon. In light of the current wealth of information pertaining to dinosaur ontogeny, we can no longer assume that all morphological differences correspond with phylogenetic distinctiveness. Accounting for ontogeny could prove as test for our phylogenies. Recognizing the ontogenetic age of immature specimens provides important insights into the life history of these animals. The immature Diplodocus specimen CMC VP14128 extends our understanding of the ontogeny of the genus and the evolution of diplodocids into new areas, where:

(1) The combination of basal and derived characters in the juvenile is broadly congruent with the phylogenetic transition from eusauropods to diplodocoids.

(2) The plesiomorphic tooth morphology is retained in immature Diplodocus and lost with maturity, and we predict this growth pattern will be seen in all other diplodocoids.

(3) As first proposed by Whitlock et al. (2010), tooth and skull morphology indicate that during growth Diplodocus inhabited different trophic levels/niches, where juveniles were generalists (i.e., browsers; Fig. 5) and more mature individuals were specialists (i.e., ground-level browsing), a pattern that we predict is ancestral for Diplodocoidea.

D. Cary Woodruff, Thomas D. Carr, Glenn W. Storrs, Katja Waskow, John B. Scannella, Klara K. Nordén and John P. Wilson. 2018. The Smallest Diplodocid Skull Reveals Cranial Ontogeny and Growth-Related Dietary Changes in the Largest Dinosaurs. Scientific Reports. 8, Article number: 14341. DOI:  10.1038/s41598-018-32620-x 

facebook.com/CaryWoodruff.7/posts/10101317027673219

 twitter.com/EEBToronto/status/1050489236418416641

Tiny Skull Illuminates the Lives of Giant Dinosaur  po.st/WYNAw9 via @SmithsonianMag

     

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

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شاهد هذا الفيديو القصير لطريقة التحميل البسيطة

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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.

[Arachnida • 2018] Tenuipalpus protium & T. kitajimai • Two New Species of Tenuipalpus sensu stricto (Acari: Tenuipalpidae) from Brazil, with A Discussion on the Ontogeny of Leg Setae ---ScRaBBlE

Tenuipalpus protium 

Castro, Beard, Ochoa, Bauchan & Feres, 2018

DOI:  10.11646/zootaxa.4540.1.12 

Abstract

The Amazon and the Cerrado are the two largest biomes in Brazil, and combined represent nearly 70% of the natural vegetation in the country. Recent surveys of the mite fauna present in these two biomes have revealed a great number of new species. In this paper, we describe the adult females, deutonymphs, protonymphs, larvae and eggs of two new species of Tenuipalpidae (Trombidiformes: Tetranychoidea), Tenuipalpus protium sp. nov., collected on Protium heptaphyllum (Burseraceae), and Tenuipalpus kitajimai sp. nov., collected on an unidentified plant of the family Sapindaceae, from the Cerrado and the Amazon Rainforest, respectively. Females of these two new species bear two distinct cuticular crests on the dorsal opisthosoma, one transverse crest anteriorly and one longitudinal crest mesally. The ontogenetic changes in the idiosomal and leg chaetotaxy of all stages are presented for both species. Adult males are not known for either species.

Keywords: Acari, flat mites, crest, body projections, taxonomy, biodiversity, Amazon Rainforest, Cerrado, LT-SEM

Elizeu B. Castro, Jennifer J. Beard, Ronald Ochoa, Gary R. Bauchan and Reinaldo J.F. Feres. 2018. Two New Species of Tenuipalpus sensu stricto (Acari: Tenuipalpidae) from Brazil, with A Discussion on the Ontogeny of Leg Setae. Zootaxa. 4540(1); 178–210. DOI:  10.11646/zootaxa.4540.1.12

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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] Ceratosaur Palaeobiology: New Insights on Evolution and Ecology of the Southern Rulers ---ScRaBBlE

 The hypothetical phylogenetic relationships of ceratosaurs based on current topologies. 

The main source is from Wang et al. (2016).

Hypothetical reconstruction of two abelisaurids showing the soft tissues on the head inferred from osteological morphology of the skull. On the top, Carnotaurus; on the bottom, Pycnonemosaurus. Art by Maurilio Oliveira. 

in Delcourt, 2018. 

  DOI:   10.1038/s41598-018-28154-x 

Abstract
Ceratosaur theropods ruled the Southern Hemisphere until the end of the Late Cretaceous. However, their origin was earlier, during the Early Jurassic, a fact which allowed the group to reach great morphological diversity. The body plans of the two main branches (Noasauridae and new name Etrigansauria: Ceratosauridae + Abelisauridae) are quite different; nevertheless, they are sister taxa. Abelisaurids have lost the ability to grasp in the most derived taxa, but the reduced forelimb might have had some display function. The ontogenetic changes are well known in Limusaurus which lost all their teeth and probably changed the dietary preference at maturity. The results presented here suggest that abelisaurids had different soft tissues on the skull. These tissues might have been associated with evolution of a strong cervicocephalic complex and should have allowed derived taxa (e.g. Majungasaurus and Carnotaurus) to have low-displacement headbutting matches. The ability to live in different semi-arid environment plus high morphological disparity allowed the ceratosaurs to become an evolutionary success.

Figure 1 The hypothetical phylogenetic relationships of ceratosaurs based on current topologies. The main source is from Wang et al. (2016). The phylogenetic position of Chenanisaurus is from Longrich et al.(2016) and the Ligabueino, Austrocheirus, Majungasaurinae and Brachyrostra are from Filippi et al.(2011).

 Figure 4 Skin structures inferred for abelisaurids. Dorsal surface of the skull of (A) Rugops (MNN IGU1), (C) Carnotaurus (MACN-CH 894) and dorsal surface of the fused nasal of (B) Abelisaurus (MPCA 11908). Scales bar: 5 cm. 

Figure 6 Hypothetical reconstruction of two abelisaurids showing the soft tissues on the head inferred from osteological morphology of the skull. On the top, Carnotaurus; on the bottom, Pycnonemosaurus.

Art by Maurilio Oliveira.

Rafael Delcourt. 2018. Ceratosaur Palaeobiology: New Insights on Evolution and Ecology of the Southern Rulers. Scientific Reports. 8, 9730.  DOI:   10.1038/s41598-018-28154-x 

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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] Reanalysis of the Phylogenetic Status of Nipponosaurus sachalinensis (Ornithopoda: Dinosauria) from the Late Cretaceous of Southern Sakhalin ---ScRaBBlE

Nipponosaurus sachalinensis Nagao, 1936

in Takasaki, Chiba, Kobayashi, et al., 2018

ニッポノサウルス || DOI: 10.1080/08912963.2017.1317766 

 blogs.yahoo.co.jp  twitter.com/NHK_n_sp

Abstract

Nipponosaurus sachalinensis is the only definitive lambeosaurine hadrosaurid from Sakhalin Island of Russia. Previous studies suggested it was a member of Lambeosaurini (derived lambeosaurines). However, its phylogenetic status within Lambeosaurini remains controversial. In addition, some studies argued the juvenile ontogenetic stage of the holotype and regarded Nipponosaurus as an invalid taxon. In order to solve these problems, its definite growth stage is determined through histological studies. Absence of a line of arrested growth, presence of osteons with large vascular spaces, and presence of primary bone remnants even in the highly modified regions of the femur confirm that the holotype was a juvenile. More than a hundred of the 350 characters used to determine the phylogenetic position of Nipponosaurus are ontogenetically variable characters based on the different ontogenetic stages of Hypacrosaurus stebingeri. Our phylogenetic analysis reveals that Nipponosaurus is a basal lambeosaurine hadrosaurid, much further down in the tree than previously suggested, and shows a polytomy with Blasisaurus and Arenyisaurus. This study also indicates that Nipponosaurus is a valid taxon because it possesses unique characters within the Lambeosaurinae (presence of massive surangular anterodorsal process, presence of lateral shelf of the dentary, and a relatively short ulna), which are independent of ontogeny.

Keywords: Dinosaur, Ornithopoda, Hadrosauridae, Nipponosaurus, ontogeny, histology

Cross section of a thighbone of Nipponosaurus (A) with an enlarged photo of the rectangular area (B). The latter shows the changing directions of the vascular canals.  

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Conclusions:

 Histological observations provide the first direct evidence that Nipponosaurus is an immature specimen. By comparing different ontogenetic stages of H. stebingeri and reviewing previous studies, up to 102 characters previously used in phylogenetic analyses are considered ontogenetically controlled within Hadrosauridae. Our phylogenetic analysis positions Nipponosaurus within a monophyletic clade of Arenysaurus and Blasisaurus, which has a sister clade relationship with the clade comprised of Parasaurolophini and Lambeosaurini. This newly recovered phylogenetic position supports a strong affinity of Asian and European lambeosaurids. The resulting relationships of this genus suggest that this taxon is valid, and represents one of the few hadrosaur specimens in Far East Asia.

Ryuji Takasaki, Kentaro Chiba, Yoshitsugu Kobayashi, Philip J. Currie and Anthony R. Fiorillo. 2018. Reanalysis of the Phylogenetic Status of Nipponosaurus sachalinensis (Ornithopoda: Dinosauria) from the Late Cretaceous of Southern Sakhalin. Historical Biology: An International Journal of Paleobiology.  5; 694-711.   DOI: 10.1080/08912963.2017.1317766

facebook.com/MuseumHokudai/posts/1569884383051928

 ニッポノサウルスの孤独 - GET AWAY TRIKE ! - Yahoo!ブログ  blogs.yahoo.co.jp/rboz_05/35175912.html
#ブログ #その他自然科学 #鳥脚類

https://twitter.com/GET_AWAY_TRIKE/status/753061281825820672

 twitter.com/NHK_n_sp/status/860992715202240513

【動画】NスペPlus 7200万年前の巨大恐竜“むかわ竜”がよみがえる！ - 世界でも珍しい全身骨格化石を手がかりに、“むかわ竜”の姿をよみがえらせました。　#むかわ竜 #恐竜 #化石  nhk.or.jp/special/plus/videos/20170522/index.html

Unraveling the mysteries of Nipponosaurus phys.org/news/2017-06-unraveling-mysteries-nipponosaurus.html via @physorg_com

Duck-Billed Dinosaur Is Japan’s Largest Complete Fossil asianscientist.com/2017/06/in-the-lab/largest-dinosaur-skeleton-nipponosaurus

    

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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.