[Bryophyta • 2018] Sphagnum incundum • A New Species in Sphagnum subg. Acutifolia (Sphagnaceae) from Boreal and Arctic Regions of North America ---ScRaBBlE

Sphagnum incundum  Flatberg & Hassel

in Kyrkjeeide, Hassel, Shaw, Shaw, Temsch & Flatberg, 2018.

 DOI:  10.11646/phytotaxa.333.1.1 

Abstract
We describe Sphagnum incundum in Sphagnum subgenus Acutifolia (Sphagnaceae, Bryophyta). We used both molecular and morphological methods to describe the new species. Molecular relationships with closely related species were explored based on microsatellites and nuclear and plastid DNA sequences. The morphological description is based on qualitative examination of morphological characters and measurements of leaves and hyalocysts. Morphological characters are compared between closely related species. The results from Feulgen densitometry and microsatellite analysis show that S. incundum is gametophytically haploid. Molecular analyses show that it is a close relative to S. flavicomans, S. subfulvum and S. subnitens, but differs both genetically and in morphological key characters, justifying the description of Sphagnum incundum as a new species. The new peatmoss is found in North America along the western coast of Greenland, in Canada from Quebec and Northwest Territories, and Alaska (United States). The new species has a boreal to arctic distribution.

Keywords: Bryophytes, Sphagnaceae

FIGURE 8. Sphagnum incundum in field surface view.
A: The type collection including selected holotype and isotypes. Collected in Ivujivik, Quebec, Canada, in intermediate, slightly sloping arctic fen.

Photo by K. I. Flatberg, 4 July 2007. Flatberg 314-07 (TRH B-9718). 

B: Together with S. squarrosum, both with young sporophytes. From Inukjuak, Quebec, Canada, in topogenous, rich fen lawn in arctic mire.

Photo by K. I. Flatberg, 14 August 2007. Flatberg 451-07 (TRH B-9999). 

Sphagnum incundum Flatberg & Hassel sp. nov. 

 Diagnosis:— Sphagnum incundum is in macro-morphology recognized by slender shoots with predominantly brownorange to purple-red capitula and straight and non-recurved leaves on innermost capitulum branches on dry plants. In micro-morphology, it is foremost recognized by narrowly lingulate stem leaves with acute to acute-obtuse apices, strongly S-shaped stem leaf hyalocysts with common occurrence of faint fibrils in distal leaf-parts, and divergent branch leaf hyalocysts on distal end convex surfaces with pores usually occupying between 1/3 and 1/2 of cell width. The new species is gametophytic haploid and closely allied morphologically to S. flavicomans, S. subfulvum, and S. subnitens.

Etymology:— The specific epithet is derived from the Latin adjective incundus = pleasant, agreeable, delightful.

 Distribution:— West Greenland, Canada in Quebec, Nunavut and North West territories, and U.S.A in Alaska. Currently known from the northern boreal to middle arctic vegetation zone. 

Ecology:— Sphagnum incundum in arctic localities in West Greenland, and Nunavik, Quebec, occurs in arctic mires on shallow peat in intermediate and rich fens, partly forming small mats and low cushions on gently sloping, soligenous mire, partly growing in small patches on lawn and carpet mire. The most commonly associated sphagna in both regions were S. concinnum (Berggr.) Flatberg (2007: 88), S. squarrosum, S. teres and S. warnstorfii Russow (1886: 315). In the boreal Anchorage area, Alaska, it was found growing in a large fen mire on high lawn patches in topogenous, varyingly intermediate to rich fen vegetation, associated with S. papillosum Lind. (1872: 280), S. subfulvum and S. miyabeanum Warnstorf (1911: 321). In Bethel area, Alaska, it occurred scattered on intermediate fen lawns in tundra mire.

 Magni Olsen Kyrkjeeide, Kristian Hassel, Blanca Shaw, A. Jonathan Shaw, Eva M. Temsch and Kjell Ivar Flatberg. 2018. Sphagnum incundum A New Species in Sphagnum subg. Acutifolia (Sphagnaceae) from Boreal and Arctic Regions of North America. Phytotaxa. 333(1); 1–21. DOI:  10.11646/phytotaxa.333.1.1

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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] Kootenayscolex barbarensis • A New Burgess Shale Polychaete and the Origin of the Annelid Head Revisited ---ScRaBBlE

Kootenayscolex barbarensis

Nanglu & Caron, 2018 

  DOI: 10.1016/j.cub.2017.12.019 

Highlights: 

•An abundant Cambrian polychaete preserves exceptional morphological details

•The new species possesses a median antenna and large palps on the prostomium

•Neuropodial chaetae are present on the mouth-bearing peristomium

•A chaetigerous origin for the peristomial portion of the annelid head is proposed

Summary

Annelida is one of the most speciose (∼17,000 species) and ecologically successful phyla. Key to this success is their flexible body plan with metameric trunk segments and bipartite heads consisting of a prostomium bearing sensory structures and a peristomium containing the mouth. The flexibility of this body plan has traditionally proven problematic for reconstructing the evolutionary relationships within the Annelida. Although recent phylogenies have focused on resolving the interrelationships of the crown group, many questions remain regarding the early evolution of the annelid body plan itself, including the origin of the head. Here we describe an abundant and exceptionally well-preserved polychaete with traces of putative neural and vascular tissues for the first time in a fossilized annelid. Up to three centimeters in length, Kootenayscolex barbarensis gen. et sp. nov. is described based on more than 500 specimens from Marble Canyon and several specimens from the original Burgess Shale site (both in British Columbia, Canada). K. barbarensis possesses biramous parapodia along the trunk, bearing similar elongate and thin notochaetae and neurochaetae. A pair of large palps and one median antenna project from the anteriormost dorsal margin of the prostomium. The mouth-bearing peristomium bears neuropodial chaetae, a condition that is also inferred in Canadia and Burgessochaeta from the Burgess Shale, suggesting a chaetigorous origin for the peristomial portion of the head and a secondary loss of peristomial parapodia and chaetae in modern polychaetes.

Keywords: Annelida, polychaete, Burgess Shale, Cambrian Explosion, body plan, prostomium, peristomium, annelid head evolution, Marble Canyon

Life reconstruction of Kootenayscolex barbarensis.

Illustration: Danielle Dufault/Royal Ontario Museum  

Kootenayscolex barbarensis is part of a group of animals called annelids (or the 'ringed worms'). It had a pair of long sensory structures called palps on its head, with a small medial antenna between them (right). Its body was covered in fleshy appendages called parapodia which bear bristles called chaetae. These structures are used for movement.

 photo: Jean-Bernard Caron/Royal Ontario Museum

Karma Nanglu and Jean-Bernard Caron. 2018. A New Burgess Shale Polychaete and the Origin of the Annelid Head Revisited. Current Biology. 28(2); p319–326.e1.  DOI: 10.1016/j.cub.2017.12.019

New 508-million-year-old bristle worm species from British Columbia's Burgess Shale wiggles into evolutionary history  phy.so/435841146 via @physorg_com

Half Billion-Year-Old Fossil Clue to How Worms Evolved  on.natgeo.com/2n58ibF via @NatGeo

   

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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] Borealopelta markmitchelli • An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics ---ScRaBBlE

Borealopelta markmitchelli 

Brown, Henderson, Vinther, Fletcher, Sistiaga, Herrera & Summons, 2017

 DOI: 10.1016/j.cub.2017.06.071 

Highlights

• A new armored dinosaur is described based on an exceptionally preserved specimen

• Abundant in situ osteoderms with keratinous sheaths and scales are preserved

• Reddish-brown coloration and crypsis in the form of countershading are indicated

• Crypsis indicates strong predation pressure on this large, heavily armored dinosaur

Summary

Predator-prey dynamics are an important evolutionary driver of escalating predation mode and efficiency, and commensurate responses of prey. Among these strategies, camouflage is important for visual concealment, with countershading the most universally observed. Extant terrestrial herbivores free of significant predation pressure, due to large size or isolation, do not exhibit countershading. Modern predator-prey dynamics may not be directly applicable to those of the Mesozoic due to the dominance of very large, visually oriented theropod dinosaurs. Despite thyreophoran dinosaurs’ possessing extensive dermal armor, some of the most extreme examples of anti-predator structures, little direct evidence of predation on these and other dinosaur megaherbivores has been documented. Here we describe a new, exquisitely three-dimensionally preserved nodosaurid ankylosaur, Borealopelta markmitchelli gen. et sp. nov., from the Early Cretaceous of Alberta, which preserves integumentary structures as organic layers, including continuous fields of epidermal scales and intact horn sheaths capping the body armor. We identify melanin in the organic residues through mass spectroscopic analyses and observe lighter pigmentation of the large parascapular spines, consistent with display, and a pattern of countershading across the body. With an estimated body mass exceeding 1,300 kg, B. markmitchelli was much larger than modern terrestrial mammals that either are countershaded or experience significant predation pressure as adults. Presence of countershading suggests predation pressure strong enough to select for concealment in this megaherbivore despite possession of massive dorsal and lateral armor, illustrating a significant dichotomy between Mesozoic predator-prey dynamics and those of modern terrestrial systems.

 Systematic Paleontology

Dinosauria Owen, 1842  

Ornithischia Seeley, 1888  

Ankylosauria Osborn, 1923  

Nodosauridae Marsh, 1890  

Borealopelta markmitchelli gen. et sp. nov. 

Etymology: The generic name Borealopelta is derived from “borealis” (Latin, “northern”) and “pelta” (Greek, “shield”), in reference to the northern locality and the preserved epidermal scales and dermal osteoderms. The specific epithet markmitchelli honors Mark Mitchell for his more than 7,000 hours of patient and skilled preparation of the holotype.

An illustration of Borealopelta markmitchelli. The study suggests that it displayed a camouflage effect known as counter-shading.

 Illustration: Julius Csotonyi/Courtesy of the Royal Tyrrell Museum of Palaeontology, Canada. 

 Illustration: Robert Nicholls 

 Illustration: Davide Bonadonna

Figure 1. Photographs of the Holotype of Borealopelta markmitchelli, TMP 2011.033.0001 Top: anterodorsolateral view; bottom: anterodorsal view. Scale bar, 10 cm. 

Holotype: The holotype is Royal Tyrrell Museum of Palaeontology (TMP) 2011.033.0001: an articulated specimen preserving the head, neck, most of the trunk and sacrum, a complete right and a partial left forelimb and manus, partial pes (Figure 1). In situ osteoderms and nearly complete soft tissue integument are preserved across dorsal and lateral surfaces of the axial skeleton, posterodorsal surface of forelimbs, and plantar surfaces of a manus and a pes. Specimen is preserved in multiple large blocks, including slabs and counter-slabs in the sacral region.

Locality and Horizon: Suncor Millennium Mine, Fort McMurray, Alberta, Canada. Wabiskaw Member, Clearwater Formation, Aptian stage. Detailed locality data are available at Royal Tyrrell Museum of Palaeontology.

Diagnosis: A nodosaurid ankylosaur characterized by the following autapomorphies (∗) and suite of characters [character/state]: cranial: dorsal skull ornamentation expressed as a large hexagonal dermal plate in frontoparietal region and multiple (>20) small dermal plates in frontonasal region∗; external nares excluded from view dorsally (shared with Pawpawsaurus) [16:1]; supraorbital ornamentation forming sharp lateral rim dorsal to orbits (shared with Gargoyleosaurus and Kunbarrasaurus) [38:2]; jugal (suborbital) horn triangular with pointed apex (shared with Gastonia, Gargoyleosaurus, and Polocanthus); jugal (suborbital) horn base longer than orbit length∗; osteoderms: cervical and thoracic osteoderms form continuous (abutting) transverse rows completely separated by continuous transverse rows of polygonal basement scales; parascapular spine is the largest osteoderm, recurved, and projects posterolaterally and horizontally (potentially shared with Sauropelta); osteoderm count for transverse rows: cervicals: C1-3, C2-3, C3-3, transition: TR-2, thoracic: T1-6∗; third and sixth transverse thoracic osteoderm rows expressed medially but pinch out laterally∗.

The new taxon can be further differentiated from Pawpawsaurus based on: dermal plate in frontonasal region (central dermal plates) flat; absence of ciliary osteoderm. Can be further differentiated from Sauropelta based on: parietals flat to slightly convex; cervical half ring has 4–6 osteoderms only; medial cervical osteoderms subequal, hexagonal, and bear prominent median ridge with posterior margin projecting beyond the basal footprint.

Figure 2: Schematic Line Drawing of TMP 2011.033.0001, the Holotype of Borealopelta markmitchelli, Illustrating Preservation of the Different Tissue Types (A) Schematic of complete specimen in dorsal view. (B and C) Skull in dorsal (B) and left lateral (C) views. (D) Close-up view of the neck, illustrating alternating cervical osteoderm bands (and preserved keratinous sheaths) and polygonal scales. (E) Close-up view of flank illustrating lateral thoracic osteoderms (with keratinous coverings) and polygonal scales. (F) Close-up view of sacral shield counterpart illustrating osteoderms and scales. (G) Close-up view of antebrachium including osteoderms and keratinous coverings. (D’–G’) Interpretive line drawings of the corresponding panels (D)–(G). Scale bars in (B)–(G), 10 cm.

Figure 3: Time-Calibrated Strict Consensus Tree Showing Position of Borealopelta markmitchelli within Ankylosauria, with Representative Well-Preserved Ankylosaurs Shown Above Bottom: time-calibrated strict consensus tree illustrating position of Borealopelta markmitchelli within Ankylosauria scaled to Jurassic and Cretaceous stages. Top: line drawings of representative well-preserved ankylosaur specimens with in situ armor and/or skin. Scale bars, 1 m.
(A) Kunbarrasaurus, QM F18101. (B) Euoplocephalus, NHMUK 5161. (C) Sauropelta, AMNH 3035 and 3036 composite. (D) Borealopelta, TMP 2011.033.0001 (this study). (E) Edmontonia, AMNH 5665.

Figure 4:  Chart Illustrating the Loss of Countershading as Body Mass Increases in Terrestrial Mammal Herbivores Chart includes pooled data for artiodactyls, perissodactyls, and proboscideans divided into body-mass bins, showing relative proportion of species that exhibit countershading. The diagonally hatched area represents the mass above which significant predation of adults does not occur. Animals illustrated above chart are representative taxa within each mass bin; species names in italics at top indicate body masses of the largest carnivores.

The Making of a Most Extraordinary Fossil

NationalGeographic.com 

The Making of a Most Extraordinary Fossil

NationalGeographic.com

on.natgeo.com/2r02aW7

Caleb M. Brown, Donald M. Henderson, Jakob Vinther, Ian Fletcher, Ainara Sistiaga, Jorsua Herrera and Roger E. Summons. 2017. An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics. Current Biology. DOI: 10.1016/j.cub.2017.06.071

Despite heavy armor, new dinosaur used camouflage to hide from predators  eurekalert.org/e/7ZWJ via @CellPressNews @EurekAlert

http://videnskab.dk/naturvidenskab/ekstremt-velbevaret-dinosaur-vidner-om-uhyggelig-fortid

It's Official: Stunning Fossil Is a New Dinosaur Species  on.natgeo.com/2vx0wxD via @NatGeo

This Is the Best Dinosaur Fossil of Its Kind Ever Found on.natgeo.com/2r02aW7 via @NatGeo

Discover How This Dinosaur Became an Extraordinary Fossil  NationalGeographic.com/magazine/2017/06/making-of-a-dinosaur-fossil-nodosaur-illustrations

Heavily armoured dinosaur had ginger camouflage to deter predators – study  theguardian.com/science/2017/aug/03/heavily-armoured-nodosaur-ginger-camouflage-predators-borealopelta-markmitchelli

Alberta museum unveils world's best-preserved armoured dinosaur  theguardian.com/science/2017/may/15/alberta-canada-museum-unveils-best-preserved-armoured-dinosaur-in-the-world-nodosaur

ติดอยู่ในกาลเวลา  ngthai.com/animals/1703 via  เนชันแนล จีโอกราฟฟิก (National Geographic) ฉบับภาษาไทย

  

  

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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] Borealopelta markmitchelli • An Exceptionally Preserved Armored Dinosaur reveals the Morphology and Allometry of Osteoderms and their Horny Epidermal Coverings ---ScRaBBlE

Borealopelta markmitchelli 

Brown, Henderson, Vinther, et al., 2017

Brown​. 2017.  DOI:  10.7717/peerj.4066  @Brown_Caleb_M

Abstract

Although the evolution and function of “exaggerated” bony projections in ornithischian dinosaurs has been subject to significant debate recently, our understanding of the structure and morphology of their epidermal keratinized coverings is greatly limited. The holotype of Borealopelta, a new nodosaurid ankylosaur, preserves osteoderms and extensive epidermal structures (dark organic residues), in anatomic position across the entire precaudal length. Contrasting previous specimens, organic epiosteodermal scales, often in the form of horn-like (keratinous) sheaths, cap and exaggerate nearly all osteoderms, allowing for morphometric and allometric analyses of both the bony osteoderms and their horny sheaths. A total of 172 osteoderms were quantified, with osteoderm spine length and height being positively allometric with respect to basal length and width. Despite tight correlations between the different measures amongst all other osteoderms, the large parascapular spines represent consistent outliers. Thickness and relative contribution of the keratinized epiosteodermal scales/sheaths varies greatly by region, ranging from 2% to 6% for posterior thoracics, to ∼25% (1.3×) for the parascapular spines—similar to horn sheaths in some bovid analogues. Relative to the bony cores, the horny portions of the spines are strongly positively allometric (slope = 2.3, CI = 1.8–2.8). Strong allometric scaling, species-specific morphology, and significant keratinous extension of the cervicoscapular spines is consistent with elaboration under socio-sexual selection. This marks the first allometric analysis of ornithischian soft tissues.

  

Figure 1: Dorsal view of TMP 2011.033.0001, showing both photocomposite and schematic line drawing.
 (A) Photocomposite dorsal view of TMP 2011.033.0001. (B) Schematic line drawing of (A) showing osteoderm regions by color. (C) Inset showing constituent blocks of TMP 2011.033.0001, and their relative position within a body outline in dorsal view. Photocomposite (A), created using separate, orthogonal images of blocks A–C, D, E, F–I, and J and combined digitally to reduce parallax. Blocks F, G, H, and I represent reflected counterpart.

  

Figure 2: Single dorsal photograph of TMP 2011.033.0001.
Sacral region represents original part—reflected counterpart shown in Fig. 4. Scale equals 1 m.

Figure 3: Interpretive scientific illustration of TMP 2011.033.0001 in dorsal view.
Sacral region represents original part—reflected counterpart shown in Fig. 4. Scale equals 1 m.

Figure 4: Composite dorsal view of TMP 2011.033.0001.
Photocomposite created using separate images of blocks A–C, D, E, F–I, and J (see Fig. 1) and combined digitally to both reduce parallax and remove gaps. Blocks F, G, H and I represent reflected counterpart of sacral part in Fig. 2. Photographs of individual blocks were digitally modified (brightness, contrast, etc.) to removed different lighting conditions, and to illustrate an average composite of the entire specimen. Scale equals 1 m.

Figure 15: Comparisons of the size of the bony core and keratinous sheath of the parascapular spine of Borealopelta to modern bovid and squamate analogues.
(A) Absolute size of the bone core (horncore or osteoderm) (yellow) and the overlying keratinous/horn sheath (grey) for the parascapular spine of TMP 2011.033.0001 (top) as well as averages for several bovid and squamate taxa (lower).
 (B) Schematic representations of the relative bony and keratinous components of select spines/horns (adjusted to same size). Data for Oreamnos americanus (n = 6, 20) and Oreamnos harringtoni (n = 10, 13) from Mead & Lawler (1995), Bos (n = 18) from Grigson (1975), Antilocapra (n = 3) and Bison (n = 18) from Borkovic (2013), Ovis nivicola (n = 2), Ovis dalli (n = 2), Ovis ammon (n = 2), Ovis canadensis nelsoni (n = 5), Ovis canadensis canadensis (n = 8), Capra ibex sibirica (n = 4) and Capra ibex ibex (n = 5) from Bubenik (1990), Trioceros (n = 1) from TMP 1990.007.0350, Phrynosoma solare (n = 1) from LACM 123351, and P. asio (n = 1) from WLH 1093.

Conclusion

The combined results showing that the osteoderm spines, and their keratinous coverings, are positively allometric (regionally); and that the anterior portion of the osteoderm series is both highly variable and has species specific morphology, provided new insights into the function and evolution of these structures. Similar results have been obtained from analysis of the exaggerated structures of most other ornithischian clades: Hadrosauridae (Dodson, 1975; Evans, 2010; McGarrity, Campione & Evans, 2013), Ceratopsia (Currie et al., 2016; Dodson, 1976; Hone, Wood & Knell, 2016; Lehman, 1990), Pachycephalosauria (Horner & Goodwin, 2009; Schott et al., 2011). These results in other ornithischian clades have been used to support the hypothesis that these exaggerated structures may have functioned, and evolved, in the context of socio-sexual selection (Hone, Wood & Knell, 2016; Hopson, 1975; Sampson, 1997). Similar hypotheses have been proposed for thyreophoran spines and plates (Carpenter, 1998; Hopson, 1977; Main et al., 2005; Padian & Horner, 2011), but until now had lacked commensurate morphometric backing. This argument is strengthened further when the parascapular spine is considered. Not only does this element show a different pattern of scaling than the rest of the series, but the absolute sizes of the keratin sheath and bony core are similar to the horns of extant bovids, and the relative sizes similar to the horns of some extant squamates, both of which are thought to function in socio-sexual display (Bustard, 1958; Farlow & Dodson, 1975; Geist, 1966). Combined with recent evidence suggesting this spine may, in life, have been pigmented differently than the rest of the osteoderms (Brown et al., 2017), this suggests this spine may have function as a visual socio-sexual display signal with conspecifics.

Caleb M. Brown​. 2017. An Exceptionally Preserved Armored Dinosaur reveals the Morphology and Allometry of Osteoderms and their Horny Epidermal Coverings. PeerJ. 5:e4066.  DOI:  10.7717/peerj.4066

New research analyses body armour of Borealopelta  RoyalTyrrellMuseum.wordpress.com/2017/11/29/new-research-analyses-body-armour-of-borealopelta/ via @RoyalTyrrell

 twitter.com/Brown_Caleb_M/status/935896521182031872

   

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

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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.