[PaleoMammalogy • 2017] A Basal Ursine Bear (Protarctos abstrusus) from the Pliocene High Arctic reveals Eurasian Affinities and A Diet Rich in Fermentable Sugars ---ScRaBBlE

Reconstruction of the mid-Pliocene Protarctos abstrusus in the Beaver Pond site area during the late summer. An extinct beaver, Dipoides, is shown carrying a tree branch in water. Plants include blackcrowberry (Empetrum nigrum) with ripened berries along the path of the bear, dwarf birch (Betula nana) in foreground; sweet gale (Myrica gale) carried by the beaver, sedges in water margins, flowering buckbeans along the mounds behind the beaver, and larch trees in distant background.

 Art by Mauricio Antón based on research of this paper

 and with input on plant community from Alice Telka. 

DOI: 10.1038/s41598-017-17657-8

Abstract

The skeletal remains of a small bear (Protarctos abstrusus) were collected at the Beaver Pond fossil site in the High Arctic (Ellesmere I., Nunavut). This mid-Pliocene deposit has also yielded 12 other mammals and the remains of a boreal-forest community. Phylogenetic analysis reveals this bear to be basal to modern bears. It appears to represent an immigration event from Asia, leaving no living North American descendants. The dentition shows only modest specialization for herbivory, consistent with its basal position within Ursinae. However, the appearance of dental caries suggest a diet high in fermentable-carbohydrates. Fossil plants remains, including diverse berries, suggests that, like modern northern black bears, P. abstrusus may have exploited a high-sugar diet in the fall to promote fat accumulation and facilitate hibernation. A tendency toward a sugar-rich diet appears to have arisen early in Ursinae, and may have played a role in allowing ursine lineages to occupy cold habitats.

Figure 2: Right (A) and left (B) lateral views of the skull of Protarctos abstrusus (CMN 54380), composite laser scans of five individual cranial fragments.

Reconstruction of the mid-Pliocene Protarctos abstrusus in the Beaver Pond site area during the late summer. An extinct beaver, Dipoides, is shown carrying a tree branch in water. Plants include blackcrowberry (Empetrum nigrum) with ripened berries along the path of the bear, dwarf birch (Betula nana) in foreground; sweet gale (Myrica gale) carried by the beaver, sedges in water margins, flowering buckbeans along the mounds behind the beaver, and larch trees in distant background.

 Art by Mauricio Antón based on research of this paper
and with input on plant community from Alice Telka.

Xiaoming Wang, Natalia Rybczynski, C. Richard Harington, Stuart C. White and Richard H. Tedford. 2017. A Basal Ursine Bear (Protarctos abstrusus) from the Pliocene High Arctic reveals Eurasian Affinities and A Diet Rich in Fermentable Sugars. Scientific Reports. 7, Article number: 17722. DOI: 10.1038/s41598-017-17657-8

Primitive fossil bear with a sweet tooth identified from Canada's High Arctic
 phy.so/432795810 via @physorg_com

Bears have had a sweet tooth for millions of years  cbc.ca/1.4451466

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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.

[PaleoMammalogy • 2018] The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses ---ScRaBBlE

The Origin and Evolutionary Biology of Pinnipeds

Berta, Churchill & Boessenecker, 2018.

DOI:  10.1146/annurev-earth-082517-010009 

@CoastalPaleo

Abstract 

The oldest definitive pinniped fossils date from approximately 30.6–23 million years ago (Ma) in the North Pacific. Pinniped monophyly is consistently supported; the group shares a common ancestry with arctoid carnivorans, either ursids or musteloids. Crown pinnipeds comprise the Otariidae (fur seals and sea lions), Odobenidae (walruses), and Phocidae (seals), with paraphyletic “enaliarctines” falling outside the crown group. The position of extinct Desmatophocidae is debated; they are considered to be closely related to both otariids and odobenids or, alternatively, to phocids. Both otariids and odobenids are known from the North Pacific, diverging approximately 19 Ma, with phocids originating in the North Atlantic or Paratethys region 19–14 Ma. Our understanding of pinniped paleobiology has been enriched by studies that incorporate anatomical and behavioral data into a phylogenetic framework. There is now evidence for sexual dimorphism in the earliest pinnipeds, heralding polygynous breeding systems, followed by increased body sizes, diving capabilities, and diverse feeding strategies in later-diverging phocid and otarioid lineages.

Keywords Pinnipedia, Otariidae, Odobenidae, Phocidae, Desmatophocidae, paleobiology 

Figure 1 Time-calibrated phylogeny of pinnipeds, showing relationships among major clades.

Figure 2 Major localities for fossil pinnipeds.

Figure 3 Life restorations of fossil pinnipeds and a close relative. 
(a) Enaliarctos mealsi (total length 1.4–1.5 m); illustrated by M. Parrish. (b) Pithanotaria starri (total length 1.26 m); illustrated by R. Boessenecker. (c) Allodesmus kernensis (total length 2.2 m); illustrated by C. Buell. (d ) Dusignathus seftoni (skull length up to 40 cm) and Valenictus chulavistensis (skull length 40 cm); illustrated by W. Stout. (e) Puijila darwini (total length just over 1 m); illustrated by C. Buell. (f) Pelagiarctos sp. (ca. 2.7 m); illustrated by R. Boessenecker.

@CoastalPaleo

Annalisa Berta, Morgan Churchill and Robert W. Boessenecker. 2018. The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses. Annual Review of Earth and Planetary Sciences. 46; 203-228. DOI:  10.1146/annurev-earth-082517-010009

 twitter.com/CoastalPaleo/status/978251979582566400

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

من هنا

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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.

[Mammalogy • 2018] Ethiopian Highlands as A Cradle of the African Fossorial Root-rats (Genus Tachyoryctes), the Genetic Evidence ---ScRaBBlE

Šumbera, Krásová, Lavrenchenko, et al., 2018.

  DOI: 10.1016/j.ympev.2018.04.003 

 Highlights

• Six major genetic clades do not correspond to the expected two or 13 root-rat species.

• Ethiopian, and not Kenyan, highlands are the cradle of the genus diversity.

• Root-rat history was shaped by climatic oscillations and complex geomorphology.

• The giant root-rat is an internal lineage of the genus modified for life in the Afroalpine.

• Root-rats and mole-rats represent different specialisations for the subterranean niche.

Abstract

Root-rats of the genus Tachyoryctes (Spalacidae) are subterranean herbivores occupying open humid habitats in the highlands of Eastern Africa. There is strong disagreement about species diversity of the genus, because some authors accept two species, while others more than ten. Species with relatively high surface activity, the giant root-rat Tachyoryctes macrocephalus, which is by far largest member of the genus, and the more fossorial African root-rat Tachyoryctes splendens, which eventually has been divided up to 12-13 species, represent two major morphological forms within the genus. In our study, we carried out a multilocus analysis of root-rats’ genetic diversity based on samples from 41 localities representing most of Tachyoryctes geographic distribution. Using two mitochondrial and three nuclear genes, we found six main genetic clades possibly representing separate species. These clades were organised into three basal groups whose branching is not well resolved, probably due to fast radiation in the late Pliocene and early Pleistocene. Climatic changes in that time, i.e. fast and repeated changes between extremely dry and humid conditions, which both limited root-rat dispersal, probably stimulated their initial genetic diversification. Contrary to expectation based on the largest root-rat diversity in Kenya (up to eight species by some authors), we found the highest diversity in the Ethiopian highlands, because all but one putative species occur there. All individuals outside of Ethiopia belong to a single recently diverged and expanded clade. This species should bear the name T. annectens (Thomas, 1891), and all other names of taxa described from outside of Ethiopia should be considered its junior synonyms. However, to solve taxonomic issues, future detailed morphological analyses should be conducted on all main clades together with genetic analysis of material from areas of their supposed contact. One of the most interesting findings of the study is the internal position of T. macrocephalus in T. splendens sensu lato. This demonstrates the intriguing phenomenon of accelerated morphological evolution of rodents occupying the Afroalpine zone in Ethiopia. Finally, we discuss how the distribution of Tachyoryctes is influenced by competition with another group of subterranean herbivores on the continent, the African mole-rats. We assume that both groups do not compete directly as previously expected, but specialisation to different subterranean niches is the main factor responsible for their spatial segregation.

Keywords: Tachyoryctes; fossorial rodent; Eastern Africa; Plio-Pleistocene climatic changes; Great Rift Valley; multi-species coalescent

 Conclusion: 

Contrary to the expectation that root-rats have their highest species diversity in the Kenyan highlands, our results convincingly demonstrated that the Ethiopian mountains are the centre of genus diversity and the cradle of the whole group. The evolution of extant root-rats took place in the Pleistocene and was affected mainly by the interplay between climate changes and the complex geomorphology, with the presence of high mountain massifs, in Ethiopia. Root-rat genetic structure in Ethiopia suggests several cryptic species that should be explored in future taxonomic work, because it is clear that current taxonomy does not reflect the evolutionary history of the genus at all. Probably all taxa described from outside Ethiopia are descendants of a single relatively recent “out-of-Ethiopia” dispersal event and should be considered as conspecific. The fact that the largest and morphologically most deviating species, T. macrocephalus, is not a sister but an internal lineage of “splendens” is further evidence of a fast morphological evolution in response to strong selection in the Afroalpine environment in Ethiopia. We may expect that more thorough genetic surveys of unique Afroalpine taxa will reveal more such findings not only in mammals, but also in other groups of vertebrates. Finally, ecological, behavioural and physiological studies could reveal how the distribution of root-rats is influenced by competition with the African mole-rats, another group of African rodents with subterranean habits.

Radim Šumbera, Jarmila Krásová, Leonid A. Lavrenchenko, Sewnet Mengistu, Afework Bekele, Ondřej Mikula and Josef Bryja. 2018. Ethiopian Highlands as A Cradle of the African Fossorial Root-rats (Genus Tachyoryctes), the Genetic Evidence. Molecular Phylogenetics and Evolution. In Press.   DOI: 10.1016/j.ympev.2018.04.003

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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.

[PaleoMammalogy • 2018] Evolutionary Adaptation to Aquatic Lifestyle in Extinct Sloths Thalassocnus Can Lead to Systemic Alteration of Bone Structure ---ScRaBBlE

Thalassocnus carolomartini McDonald & Muizon, 2002

 Amson, Billet & de Muizon, 2018

 DOI: 10.1098/rspb.2018.0270

Illustration: Oliver Demuth   twitter.com/OliverDemuth 

Abstract 

Through phenotypic plasticity, bones can change in structure and morphology, in response to physiological and biomechanical influences over the course of individual life. Changes in bones also occur in evolution as functional adaptations to the environment. In this study, we report on the evolution of bone mass increase (BMI) that occurred in the postcranium and skull of extinct aquatic sloths. Although non-pathological BMI in postcranial skeleton has been known in aquatic mammals, we here document general BMI in the skull for the first time. We present evidence of thickening of the nasal turbinates, nasal septum and cribriform plate, further thickening of the frontals, and infilling of sinus spaces by compact bone in the late and more aquatic species of the extinct sloth Thalassocnus. Systemic bone mass increase occurred among the successively more aquatic species of Thalassocnus, as an evolutionary adaptation to the lineage's changing environment. The newly documented pachyostotic turbinates appear to have conferred little or no functional advantage and are here hypothesized as a correlation with or consequence of the systemic BMI among Thalassocnus species. This could, in turn, be consistent with a genetic accommodation of a physiological adjustment to a change of environment.

Keywords: bone mass increase, evolutionary adaptation, phenotypic plasticity, physiological adjustment, Thalassocnus, turbinates

Conclusion: 

Systemic bone structure alteration, formerly known exclusively as a physiological adjustment, was here evidenced to have been retained as an evolutionary adaptation thanks to the outstandingly detailed (both in terms of geological age and anatomy) and early-stage record of a land-to-sea transition in the extinct sloth Thalassocnus. This new result is consistent with a macroevolutionary process of selection on environmentally induced variation of phenotypic plasticity [Gause, 1942; Sultan, 2017]. In other words, the systemic alteration of the highly plastic bone structure that gradually evolved among the species of Thalassocnus may represent an example of a macroevolutionary transition from a phenotypic accommodation (to an environmental change) to a genetic accommodation. In the context of the so-called extended (evolutionary) synthesis, Pigliucci [2010] points out the difficulty of uncovering such examples, which are required to corroborate the hypothesis that phenotypic plasticity has an important macroevolutionary role.

The precise mechanism causing an adjustment (over the course of an individual's life) of bone structure in response to life in water is not understood. However, one can speculate that the shift of a terrestrial animal to an aquatic environment involves an increase in exercise intensity, which was shown to induce BMI [Lieberman, 1996; Biewener & Bertram, 1994]. There does not seem to be a clear influence of swimming on the bone mass of athletes [Gómez-Bruton, et al., 2013] (but differences in other physical activities probably prevent a direct correlation assessment in humans [Gómez-Bruton, et al., 2016]). However, rats that were swim-trained during growth have a greater overall bone mineral content and bone surface than the sedentary controls [McVeigh, et al., 2010] (but bone mineral density did not differ; and see [Bourrin, et al., 1992] for the opposite effect of endurance swim training on trabecular bone). It is noteworthy, however, that swim-trained animals do not necessarily experience a greater overall exercise intensity, as they were found to voluntarily run less outside the experimental exercise than control and running groups [McVeigh, et al., 2010]. Furthermore, bone structure at locations not directly influenced by locomotion, such as the cranial vault, does not seem to have been investigated in swim-trained animals.

The lack of a similarly detailed fossil record in other ancestrally terrestrial tetrapods adapted to an aquatic lifestyle prevented drawing such a conclusion in their respective cases, but a similar process might have occurred during the evolutionary history of at least some of them. BMI is probably the most widespread lifestyle adaptation among aquatic tetrapods. This suggests that genetic accommodation of a trait subject to physiological adjustment such as bone structure alteration might have played an important role in great evolutionary transitions, of which the secondary adaptations of tetrapods to an aquatic lifestyle is an iconic example.

Eli Amson, Guillaume Billet and Christian de Muizon. 2018. Evolutionary Adaptation to Aquatic Lifestyle in Extinct Sloths Can Lead to Systemic Alteration of Bone Structure.  Proc. R. Soc. B. 285: 20180270. DOI: 10.1098/rspb.2018.0270

  

The paper about the crazy pachyosteosclerosis in the skull of the marine sloth #Thalassocnus was published this morning in @RSocPublishing Proceedings B: doi.org/10.1098/rspb.2018.0270 …, to which I contributed my art. It was a pleasure to work with authors. #PaleoArt #SciArt

 twitter.com/OliverDemuth/status/994134938344620032
 facebook.com/photo.php?fbid=10211011701159876 

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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] Trachemys haugrudi • A New Slider Turtle (Testudines: Emydidae: Deirochelyinae) from the late Hemphillian (late Miocene/early Pliocene) of eastern Tennessee and the Evolution of the Deirochelyines ---ScRaBBlE

Trachemys haugrudi  Jasinski, 2018

DOI: 10.7717/peerj.4338 

Artwork by Mary P. Williams

Abstract

Trachemys (Testudines: Emydidae) represents one of the most well-known turtle genera today. The evolution of Trachemys, while being heavily documented with fossil representatives, is not well understood. Numerous fossils from the late Hemphillian Gray Fossil Site (GFS) in northeastern Tennessee help to elucidate its evolution. The fossil Trachemys at the GFS represent a new species. The new taxon, Trachemys haugrudi, is described, and currently represents the most thoroughly described fossil emydid species known. A phylogenetic analysis, including 31 species, focusing on the subfamily Deirochelyinae is performed that includes the new fossil species, along with numerous other modern and fossil deirochelyine species, representing the first phylogenetic analysis published that includes several fossil deirochelyines. The phylogenetic analysis, utilizing morphological evidence, provides monophyletic clades of all modern deirochelyines, including Chrysemys, Deirochelys, Pseudemys, Malaclemys, Graptemys, and Trachemys. A strict consensus tree finds the recently described fossil species Graptemys kerneri to be part of a clade of Graptemys + Malaclemys. Three fossil taxa, including one previously referred to Pseudemys (Pseudemys caelata) and two to Deirochelys (Deirochelys carri and Deirochelys floridana) are found to form a clade with modern Deirochelys reticularia reticularia, with D. floridana sister to the other members of the clade. Chrysemys is found to be part of a basal polytomy with Deirochelys in relation to other deirochelyine taxa. Two fossil taxa previously referred to Chrysemys (Chrysemys timida and Chrysemys williamsi) form a paraphyly with the modern Chrysemys picta picta and Deirochelys, and may be referable to distinct genera. Additionally, fossil taxa previously attributed to Trachemys (Trachemys hillii, Trachemys idahoensis, Trachemys inflata, and Trachemys platymarginata) and T. haugrudi are found to form a clade separate from clades of northern and southern Trachemys species, potentially suggesting a distinct lineage of Trachemys with no modern survivors. Hypotheses of phylogenetic relationships mostly agree between the present study and previous ones, although the inclusion of fossil taxa provides further clues to the evolution of parts of the Deirochelyinae. The inclusion of more fossil taxa and characters may help resolve the placement of some taxa, and further elucidate the evolution of these New World turtles.

Figure 7: Trachemys haugrudi, paratype skull (ETMNH–3562) in dorsal view. (A) Dorsal portion in dorsal view; (B) ventral portion in dorsal view; (C) reconstruction of skull in dorsal view. Area shaded gray is not preserved and has been reconstructed. Dotted lines represent sutures that were not clear in the specimen. Skull has been reconstructed in the slightly deformed state the specimen is in in real life.

 cs, crista supraoccipitalis; den, dentary; ?ex, ?exoccipital; fr, frontal; ?ju, ?jugal; mx, maxilla; ?op, ?opisthotic; pa, parietal; pf, prefrontal; pm, premaxilla; po, postorbital; ?pr, prootic; ?qj, ?quadratojugal; ?qu, ?quadrate; so, supraoccipital; ?sq, ?squamosal. Scale bars are 1 cm. 

Figure 3: Trachemys haugrudi, holotype shell (ETMNH–8549). (A) Dorsal view of carapace; (B) line drawing of carapace in dorsal view, with bones outlined in black and scutes outlined in gray; and (C) with scutes outlined in black and bones outlined in gray. Missing portions are shaded in gray. Scale bar is 10 cm.

Figure 4: Trachemys haugrudi, holotype shell (ETMNH–8549). (A) Ventral view of plastron; (B) line drawing of plastron in dorsal view, with bones outlined in black and scutes outlined in gray; and (C) with scutes outlined in black and bones outlined in gray. Scale bar is 10 cm.

Systematic Paleontology

Class Reptilia Laurenti, 1768

Order Testudines Linnaeus, 1758

Suborder Cryptodira Cope, 1868

Superfamily Testudinoidea sensu Gaffney & Meylan, 1988

Family Emydidae Bell, 1825

Trachemys Agassiz, 1857

Trachemys haugrudi n. sp.

Type horizon and age: Late Miocene–early Pliocene (late Hemphillian LMA, 7.0–4.5 Ma). This range means the fossil locality, and T. haugrudi, lies somewhere within Hh3–Hh4 (see Tedford et al., 2004 for discussion of substages).

Etymology: The specific name honors Shawn Haugrud, preparator at the GFS who spent countless hours working on many of the specimens cited within and who helped piece this ancient turtle back together.

Diagnosis: Trachemys haugrudi is placed in the Emydidae due to the absence of musk ducts, inframarginals reduced to two, normal hexagonal neurals 2–8 (also occurs in a few batagurids (=geoemydids); e.g., Mauremys), and costal-inguinal buttress confined to C5. It is placed in the Deirochelyinae due to distinct lack of pectoral overlap of the entoplastron and lack of a hingable plastral lobe with ligamentous bridge connection (also present in some emydines). Diagnosed as a member of the genus Trachemys by features discussed by Seidel & Jackson (1990), including the combination of: a posteriorly strongly serrated oval carapace; a vertebral keel; low longitudinal ridges (mainly on pleurals (and costals)); alternating seams of the vertebral and pleural scutes that do not align; ......

Figure 13: Life reconstruction of Trachemys haugrudi during the late Hemphillian at the Gray Fossil Site in eastern Tennessee.
 Several taxa that would have lived alongside T. haugrudi are also shown, including Caudata indeterminate, Tapirus polkensis, cf. Machairodus sp., and Pristinailurus bristoli (Wallace & Wang, 2004; Boardman & Schubert, 2011b; Schubert, 2011; Jasinski, 2013a). Artwork by Mary P. Williams, with permission.  

Steven E. Jasinski. 2018.  A New Slider Turtle (Testudines: Emydidae: Deirochelyinae: Trachemys) from the late Hemphillian (late Miocene/early Pliocene) of eastern Tennessee and the Evolution of the Deirochelyines. PeerJ. 6:e4338.  DOI: 10.7717/peerj.4338

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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.