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 Ootaxa. Show all posts
Showing posts with label Ootaxa. Show all posts

Wednesday, March 20, 2019

[Paleontology • 2017] Beibeilong sinensis • Perinate and Eggs of A Giant Caenagnathid Dinosaur from the Late Cretaceous of central China ---ScRaBBlE


 Beibeilong sinensis
Pu, Zelenitsky, Lü, Currie, Carpenter, Xu, Koppelhus, Jia, Xiao, Chuang, Li, Kundrát & Shen, 2017DOI: 10.1038/NComms14952

Abstract
The abundance of dinosaur eggs in Upper Cretaceous strata of Henan Province, China led to the collection and export of countless such fossils. One of these specimens, recently repatriated to China, is a partial clutch of large dinosaur eggs (Macroelongatoolithus) with a closely associated small theropod skeleton. Here we identify the specimen as an embryo and eggs of a new, large caenagnathid oviraptorosaur, Beibeilong sinensis. This specimen is the first known association between skeletal remains and eggs of caenagnathids. Caenagnathids and oviraptorids share similarities in their eggs and clutches, although the eggs of Beibeilong are significantly larger than those of oviraptorids and indicate an adult body size comparable to a gigantic caenagnathid. An abundance of Macroelongatoolithus eggs reported from Asia and North America contrasts with the dearth of giant caenagnathid skeletal remains. Regardless, the large caenagnathid-Macroelongatoolithus association revealed here suggests these dinosaurs were relatively common during the early Late Cretaceous.

Systematic palaeontology 

Theropoda Marsh 1881
Oviraptorosauria Barsbold 1976
Caenagnathidae Sternberg 1940

 Beibeilong sinensis gen. et sp. nov.

Figure 1: Photograph of eggs and skeleton of Beibeilong sinensis (HGM 41HIII1219).
Right image shows schematic overlay of approximate locations of individual eggs. Eggs 1 through 4 are in an upper layer just beneath the skeleton, whereas Egg 5 is in a lower layer of the block. Scale bar is in centimetre.

The fossil (left) and a digital overlay (right) shows where the eggs were placed before they broke and fossilized. Notice the skeleton of the embryo next to the ruler. 


Holotype. HGM 41HIII1219, a small, semi-articulated skeleton (‘Baby Louie’) associated with a partial nest of 6–8 eggs. The specimen is housed in the Henan Geological Museum (HGM), Zhengzhou, China.

the curled embryo of Beibelong on top of the eggs (eggshell is dark grey in color).
Photograph by Darla Zelenitsky, University of Calgary 

An illustration of Beibeilong embryo and egg fossil, with reconstruction of skeleton and fleshed-out models to the right. 

Figure 5: Reconstruction of Beibeilong embryo in ovo.
The drawing shows the approximate size of the Beibeilong embryo inside a Macroelongatoolithus egg.
drawn by Vladimir Rimbala

 Diagnosis. A large caenagnathid that has the following unique suite of features: antorbital fossa demarcated by sharply defined alveolar and dorsoposterior trending ridges, posterodorsal margin of lacrimal overlapped by frontal, subantorbital portion of the maxilla is inset medially, pronounced retroarticular process with a distinct concave posterior facet (roughly as tall at the base as it is wide), preacetabular process of the ilium longer than postacetabular process, posterior end of the postacetabular process truncated or broadly rounded, and accessory trochanter of the femur weakly developed.

 Locality and horizon. The specimen was discovered at a latitude/longitude of 33°15′30″ N, 111°43′41″ E in Heimaogou, 2 km east of Zhaoying Village, Yangcheng Township, Xixia County, Henan Province, People’s Republic of China. The locality is in the Upper Cretaceous Gaogou Formation (Cenomanian—Turonian)

Etymology. The generic name is derived from Chinese Pinyin ‘beibei’ for baby and ‘long’ for dragon. The specific name is derived from Latin referring to its discovery in China.

Beibeilong sinensis lived about 90 million years ago, during the Cretaceous period. The adults of this species were enormous, measuring up to 8 meters long from the snout to the end of the tail, and weighing up to 3,000 kilograms when fully grown at age 11.
Illustration: Zhao Chuang  

  
Hanyong Pu, Darla K. Zelenitsky, Junchang Lü, Philip J. Currie, Kenneth Carpenter, Li Xu, Eva B. Koppelhus, Songhai Jia, Le Xiao, Huali Chuang, Tianran Li, Martin Kundrát and Caizhi Shen. 2017. Perinate and Eggs of A Giant Caenagnathid Dinosaur from the Late Cretaceous of central China.  Nature Communications. 8, Article number: 14952. DOI: 10.1038/ncomms14952

First baby of a gigantic Oviraptor-like dinosaur belongs to a new species
 eurekalert.org/e/7Xft via @UCalgary @EurekAlert
'Baby Dragon' Dinosaur Found Inside Giant Egg  on.NatFeo.com/2pYHLPO via @NatGeo
Embryo of Colossal Dinosaur Was Preserved for 90 Million Years
shar.es/1FDLTy via @LiveScience

  
   

---------------------------------------------------------------
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] Incubation Behaviours of Oviraptorosaur Dinosaurs in Relation to Body Size ---ScRaBBlE


 egg incubation in oviraptorosaurs showing small species sat on the eggs (upper), whereas giant species rested in the central opening of the clutch (lower).

in Tanaka, Zelenitsky, Lü, et al., 2018. 
Reconstruction by Masato Hattori.   marchan-forest.blogspot.com

Abstract
Most birds sit on their eggs during incubation, a behaviour that likely evolved among non-avian dinosaurs. Several ‘brooding' specimens of smaller species of oviraptorosaurs and troodontids reveal these non-avian theropods sat on their eggs, although little is known of incubation behaviour in larger theropod species. Here we examine egg clutches over a large body size range of oviraptorosaurs in order to understand the potential effect of body size on incubation behaviour. Eggshell porosity indicates that the eggs of all oviraptorosaurs were exposed in the nest, similar to brooding birds. Although all oviraptorosaur clutches consist of radially arranged eggs in a ring configuration, clutch morphology varies in that the central opening is small or absent in the smallest species, becomes significantly larger in larger species, and occupies most of the nest area in giant species. Our results suggest that the smallest oviraptorosaurs probably sat directly on the eggs, whereas with increasing body size more weight was likely carried by the central opening, reducing or eliminating the load on the eggs and still potentially allowing for some contact during incubation in giant species. This adaptation, not seen in birds, appears to remove the body size constraints of incubation behaviour in giant oviraptorosaurs.

KEYWORDS: dinosaur, egg, incubation, nest, Oviraptorosauria, Theropoda


 Reconstruction of egg incubation in oviraptorosaurs showing small species sat on the eggs (upper),
whereas giant species rested in the central opening of the clutch (lower).

Illustration is drawn by Masato Hattori.

Kohei Tanaka, Darla K. Zelenitsky, Junchang Lü, Christopher L. DeBuhr, Laiping Yi, Songhai Jia, Fang Ding, Mengli Xia, Di Liu, Caizhi Shen and Rongjun Chen. 2018. Incubation Behaviours of Oviraptorosaur Dinosaurs in Relation to Body Size. BIOLOGY LETTERS. DOI: 10.1098/rsbl.2018.0135

    

How huge dinosaurs nested without crushing their eggs cbc.ca/1.4602808 

---------------------------------------------------------------
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.

[PaleoOrnithology • 2019] Avimaia schweitzerae • An Early Cretaceous Enantiornithine (Aves) Preserving An Unlaid Egg and Probable Medullary Bone ---ScRaBBlE


Avimaia schweitzerae 
Bailleul, O’Connor, Zhang, Li, Wang, Lamanna, Zhu & Zhou, 2019

Reconstruction by Michael Rothman 

Abstract
Understanding non-crown dinosaur reproduction is hindered by a paucity of directly associated adults with reproductive traces. Here we describe a new enantiornithine, Avimaia schweitzerae gen. et sp. nov., from the Lower Cretaceous Xiagou Formation with an unlaid egg two-dimensionally preserved within the abdominothoracic cavity. Ground-sections reveal abnormal eggshell proportions, and multiple eggshell layers best interpreted as a multi-layered egg resulting from prolonged oviductal retention. Fragments of the shell membrane and cuticle are both preserved. SEM reveals that the cuticle consists of nanostructures resembling those found in neornithine eggs adapted for infection-prone environments, which are hypothesized to represent the ancestral avian condition. The femur preserves small amounts of probable medullary bone, a tissue found today only in reproductively active female birds. To our knowledge, no other occurrence of Mesozoic medullary bone is associated with indications of reproductive activity, such as a preserved egg, making our identification unique, and strongly supported.

Fig. 1 Photograph and line drawing of the holotype of Avimaia schweitzerae, IVPP V25371.
a Photograph of the partial skeleton with feather impressions, and the crushed preserved egg between the pubes; b interpretive line drawing, with white arrows indicating the two fragments extracted for microscopic analysis with a super-imposed CT-scan revealing the egg and underlying elements of the right pelvis in dorsal (synsacrum) and medial (ilium) view.
Gray denotes bones (darker gray indicating poor preservation), blue denotes the egg, and dark gray denotes feather impressions.
 cv caudal vertebra, d digit, dp dorsal process, f fibula, fc fibular crest, fe femur, if ilioischiadic foramen, il ilium, is ischium, l left, mt metatarsal, p pedal phalanx, pu pubis, py pygostyle, r right, ri rib, sy synsacrum, tb tibiotarsus, tm tarsometatarsus, tv thoracic vertebra. 
Scale bar is 1 cm.

  Photograph of the holotype of Avimaia schweitzerae.
(Image by Barbara Marrs) 

Systematic paleontology
Aves Linnaeus, 1758
Pygostylia Chiappe, 2002

Ornithothoraces Chiappe, 1995
Enantiornithes Walker, 1981

Avimaia schweitzerae gen. et sp. nov.

Etymology: The generic name Avi- (bird) maia (mother) refers to the fact the specimen is a female preserved with an egg in the body cavity. Schweitzerae is in honor of Mary Higby Schweitzer for her ground-breaking works on MB and for her role in establishing the field of molecular paleontology.

Holotype: IVPP V25371 (Institute of Vertebrate Paleontology and Paleoanthropology), an articulated partial skeleton with some feather traces, consisting of the caudal half of the axial column, the pelvis, and the hind limbs, mostly exposed ventrolaterally (Fig. 1).

Locality and horizon: Near Changma Village, Yumen City, Gansu Province, northwestern China; Lower Cretaceous (lower–middle Aptian) Xiagou Formation10.

Diagnosis: Small-bodied enantiornithine (robust, cranially forked pygostyle, distal condyles of tibiotarsus contacting medially, J-shaped metatarsal I, metatarsal IV mediolaterally reduced relative to metatarsals III and IV, metatarsal IV trochlea reduced to single condyle) with the following autapomorphies: pubis delicate and strongly curved so that the caudal margin is concave throughout; distal end of ischium dorsally curved.


 Reconstruction of the Xiagou Formation with colonial nesting ground of Avimaia schweitzerae.
The female individual dead in the water on the left (with an unlaid egg not visible inside its abdomen), represents the fossilized individual described here.
(Image by Michael Rothman)

Alida M. Bailleul, Jingmai O’Connor, Shukang Zhang, Zhiheng Li, Qiang Wang, Matthew C. Lamanna, Xufeng Zhu and Zhonghe Zhou. 2019.  An Early Cretaceous Enantiornithine (Aves) Preserving An Unlaid Egg and Probable Medullary Bone. Nature Communications. volume 10, 1275. DOI: 10.1038/s41467-019-09259-x 

New Cretaceous Fossil Sheds Light on Avian Reproduction -    english.cas.cn/newsroom/research_news/201903/t20190320_207048.shtml 
New Cretaceous fossil sheds light on avian reproduction  eurekalert.org/e/933b via @EurekAlert

---------------------------------------------------------------
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