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Post by brobear on Mar 27, 2018 3:50:20 GMT -5
prehistoric-fauna.com/Kretzoiarctos-beatrix Kretzoiarctos beatrix Kretzoiarctos beatrix, (Kretzoiarctos beatrix Abella, 2011) Synonyms: Ursavus depereti Fraile, 1997, Ursavus primaevus Álvarez Sierra, 2003, Agriarctos beatrix (?) Abella, 2011 Order: Carnivora Suborder: Caniformia Family: Ursidae Subfamily: Ailuropodinae Size: 1.3 m in length, 50 - 70 cm in height, 60 kg of weight ...( 132 pounds ). Time period: the Miocene of Europe (12 - 11 million years ago) Typical representative: Kretzoiarctos beatrix Abella, 2011 Kretzoiarctos beatrix is an extinct bear from the European Miocene and an ancestor of the extant giant panda. Kretzoiarctos beatrix is the ancestral group of the Ailuropodinae subfamily according to fossil records from the middle Miocene of Spain. Based on teeth structure, researchers have speculated that this species may have been a small herbivorous animal that ate very hard plants.The giant panda (Ailuropoda melanoleuca) has a special craniodental structure that serves as a durophagous feeding adaptation for bamboo, and a similar tooth structure was also found in K. beatrix., indicating that this species may be the oldest relative of the giant panda and might have resembled it in appearance. Unlike most of the Ursoidea species, K. beatrix had strong distal cusps on the premolars and a relatively forward-positioned metaconid. In addition, K. beatrix had a more strongly developed sectorial blade in the trigonid, and relatively shorter second molar talonid. These traits indicate a need for pronounced chewing and grinding, and suggest that these enhanced molars and premolars were evolved to more efficiently break down hard plant tissues. The fossil records for these teeth structure suggest that the early development of the distal and mesial cusps on the premolars of K. beatrix may indicate an evolutionary trend towards more complex premolars for the plant-feeding Ursoidea species, and may explain why extant giant pandas have very complex molars. A hypothetical explanation for the extinction of K. beatrix is based on climate and environmental changes. In the early Turolian, high precipitation and humid environments in Western Europe favored smaller plant-feeding animals like Kretzoiarctos species. However, severe climate changes during the late Miocene led to widespread extinctions. A crucial event in this period is the Messinian salinity crisis, a huge decrease in Mediterranean Sea level due to evaporation and desiccation. This has been put forward as a possible cause for the significant decline in Ursidae species diversity in the late Miocene, including the species of the genus Kretzoiarctos.
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Post by brobear on Oct 21, 2018 10:21:26 GMT -5
prehistoric-fauna.com/Kretzoiarctos-beatrix Kretzoiarctos beatrix 3 reviews Kretzoiarctos beatrix, (Kretzoiarctos beatrix Abella, 2011) Synonyms: Ursavus depereti Fraile, 1997, Ursavus primaevus Álvarez Sierra, 2003, Agriarctos beatrix (?) Abella, 2011 Order: Carnivora Suborder: Caniformia Family: Ursidae Subfamily: Ailuropodinae Size: 1.3 m in length, 50 - 70 cm in height, 60 kg of weight Time period: the Miocene of Europe (12 - 11 million years ago) Typical representative: Kretzoiarctos beatrix Abella, 2011 Kretzoiarctos beatrix is an extinct bear from the European Miocene and an ancestor of the extant giant panda. Kretzoiarctos beatrix is the ancestral group of the Ailuropodinae subfamily according to fossil records from the middle Miocene of Spain. Based on teeth structure, researchers have speculated that this species may have been a small herbivorous animal that ate very hard plants.The giant panda (Ailuropoda melanoleuca) has a special craniodental structure that serves as a durophagous feeding adaptation for bamboo, and a similar tooth structure was also found in K. beatrix., indicating that this species may be the oldest relative of the giant panda and might have resembled it in appearance. Unlike most of the Ursoidea species, K. beatrix had strong distal cusps on the premolars and a relatively forward-positioned metaconid. In addition, K. beatrix had a more strongly developed sectorial blade in the trigonid, and relatively shorter second molar talonid. These traits indicate a need for pronounced chewing and grinding, and suggest that these enhanced molars and premolars were evolved to more efficiently break down hard plant tissues. The fossil records for these teeth structure suggest that the early development of the distal and mesial cusps on the premolars of K. beatrix may indicate an evolutionary trend towards more complex premolars for the plant-feeding Ursoidea species, and may explain why extant giant pandas have very complex molars. A hypothetical explanation for the extinction of K. beatrix is based on climate and environmental changes. In the early Turolian, high precipitation and humid environments in Western Europe favored smaller plant-feeding animals like Kretzoiarctos species. However, severe climate changes during the late Miocene led to widespread extinctions. A crucial event in this period is the Messinian salinity crisis, a huge decrease in Mediterranean Sea level due to evaporation and desiccation. This has been put forward as a possible cause for the significant decline in Ursidae species diversity in the late Miocene, including the species of the genus Kretzoiarctos.
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Post by Deleted on Mar 18, 2019 8:16:45 GMT -5
So even the giant panda has extinct relatives I wish that these extinct bears were alive today.
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Post by brobear on Mar 18, 2019 8:18:28 GMT -5
So even the giant panda has extinct relatives I wish that these extinct bears were alive today. Every living creature has extinct relatives
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Post by brobear on Jan 6, 2020 2:22:15 GMT -5
Ailuropoda is the only extant genus in the ursid (bear) subfamily Ailuropodinae. It contains one living and three fossil species of panda.
Only one species—Ailuropoda melanoleuca—currently exists; the other four species are prehistoric chronospecies. Despite its taxonomic classification as a carnivoran, the giant panda has a diet that is primarily herbivorous, which consists almost exclusively of bamboo.
Giant pandas have descended from Ailurarctos, which lived during the late Miocene.
In 2011 fossil teeth from over 11 mya found in the Iberian peninsula were identified as belonging to a previously unidentified species in the Ailuropodinae subfamily. This species was named Agriarctos beatrix - (now Kretzoiarctos).
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Post by brobear on Jan 6, 2020 2:25:45 GMT -5
www.livescience.com/24788-oldest-panda-fossils.htmlOldest Panda Fossils Found in Surprising Place. All giant pandas may come from China, but fossils reveal that the oldest known ancestor of the lineage dwelled in Spain, researchers say. The giant panda (Ailuropoda melanoleuca) is known worldwide for its black-and-white fur. The giant panda is unique among bears for dining almost entirely on bamboo — other members of the bear family are omnivorous or mostly carnivorous. Genetic evidence suggests the ancestors of giant pandas diverged from other bears 18 million to 22 million years ago. However, much remains uncertain about what early giant pandas were like and how this lineage of bears changed over time — before the new find, the earliest undisputed giant panda fossils recovered were about 8.2 million years old at most, and were from China. The species belongs to a newly declared genus, Kretzoiarctos, which means "bears of Kretzoi," named after paleontologist Miklos Kretzoi, who had discovered other extinct panda species. The species is named Kretzoiarctos beatrix, with "beatrix" referring to a colleague of the researchers, Spanish paleontologist Beatriz Azanza. [Butter Balls: Photos of Playful Pandas] The fossils date back 11.6 million years to the middle of the Miocene Epoch, when the area was humid, moderately warm, and forested. "The new genus we describe in this paper is not only the first bear recorded in the Iberian Peninsula, but also the first of the giant panda's lineage," said researcher Juan Abella, a paleontologist in Madrid at Spain's National Museum of Natural Sciences. This new bear would have weighed no more than 130 pounds (60 kilograms), making it more or less the size of the sun bear (Helarctos malayanus), the smallest living bear species. Judging by its teeth, it was an omnivore, but it possessed many dental features of bears adapted to eating tough plant materials such as bamboo. "It had a very wide variety of food available to it, from meat and fruit to plant stems or even leaves," Abella told LiveScience. "We are unaware if there was bamboo in Spain during the Middle Miocene, but there were many other similar plants associated with humid climates available for Kretzoiarctos." It remains uncertain whether Kretzoiarctos was colored the same way as modern giant pandas, as no hair from it remains. However, Abella speculated the primitive coloration for this group of bears was also dark with several white patches. This is based on the fact that most bear cubs have this coloration — in many animals, biological patterns seen among the young reflect what their ancestors were like. These findings might suggest a Western European origin for the giant panda lineage. However, the fossil record of this group of bears is still too scarce and fragmentary to say for certain where they arose, researchers said. Another mystery: Why did Kretzoiarctos go extinct? "The most probable cause is likely to be the opening up of the forests, giving way to more open, drier spaces and the appearance of similar yet larger and more competitive species," Abella said.
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Post by brobear on Jan 6, 2020 2:34:04 GMT -5
journals.plos.org/plosone/article?id=10.1371/journal.pone.0048985 Conclusions A new genus of extinct ursid belonging to the giant panda lineage, Kretzoiarctos gen. nov. (Ursidae: Ailuropodinae: Ailuropodini), is here described on the basis of new fossil remains from the Spanish site ACM/C6-Camí (Vallès-Penedès Basin). This new material allows a more precise taxonomic approach of the type material from the also Spanish locality of Nombrevilla 2 (Calatayud-Daroca Basin), previously attributed to the Late Miocene genus Agriarctos. With a late Middle Miocene age, Kretzoiarctos represents the oldest known member not only of the tribe Ailuropodini, but also of the whole subfamily Ailuropodinae (Ailuropodini + Indarctini), substantially preceding in time the other taxa that had been previously attributed to this group. Given that Kretzoiarctos is only known from the Iberian Peninsula (Calatayud-Daroca and Vallès-Penedès basins), a Western European origin of the giant panda lineage (Ailuropodinae) is now tentatively supported by the results of this paper. It should be taken into account, however, that the fossil record of this group is still too scarce and fragmentary, as evidenced by the various ghost lineages that must be inferred based on the Early Miocene divergence times for ailuropodines suggested by molecular data. The fossil remains of Kretzoiarctos reported here, however, at least conclusively document the occurrence of ailuropodines by the Middle Miocene of Eurasia, with Ballusia and Ursavus displaying a successive basal position with regard to crown ursids as a whole.
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Post by King Kodiak on May 3, 2020 12:10:54 GMT -5
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Post by brobear on Jun 7, 2020 4:51:23 GMT -5
Kretzoiarctos beatrix compared with giant panda:
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Post by OldGreenGrolar on Jun 7, 2020 5:00:18 GMT -5
The Beatrix looks like the opposite of the giant panda (almost) in terms of the arrangement of its black and white fur.
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Post by brobear on Jun 7, 2020 5:39:05 GMT -5
The Beatrix looks like the opposite of the giant panda (almost) in terms of the arrangement of its black and white fur. Simply from the imagination of the artist. Fossils do not reveal color.
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Post by OldGreenGrolar on Jun 7, 2020 6:14:10 GMT -5
I am an amateur artist so I understand where you are getting at. Still I really like the Beatrix.
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Post by King Kodiak on Jul 16, 2020 0:01:26 GMT -5
Kretzoiarctos gen. nov., the Oldest Member of the Giant Panda Clade
The phylogenetic position of the giant panda, Ailuropoda melanoleuca (Carnivora: Ursidae: Ailuropodinae), has been one of the most hotly debated topics by mammalian biologists and paleontologists during the last century. Based on molecular data, it is currently recognized as a true ursid, sister-taxon of the remaining extant bears, from which it would have diverged by the Early Miocene. However, from a paleobiogeographic and chronological perspective, the origin of the giant panda lineage has remained elusive due to the scarcity of the available Miocene fossil record. Until recently, the genus Ailurarctos from the Late Miocene of China (ca. 8-7 mya) was recognized as the oldest undoubted member of the Ailuropodinae, suggesting that the panda lineage might have originated from an Ursavus ancestor. The role of the purported ailuropodine Agriarctos, from the Miocene of Europe, in the origins of this clade has been generally dismissed due to the paucity of the available material. Here, we describe a new ailuropodine genus, Kretzoiarctos gen. nov., based on remains from two Middle Miocene (ca. 12-11 Ma) Spanish localities. A cladistic analysis of fossil and extant members of the Ursoidea confirms the inclusion of the new genus into the Ailuropodinae. Moreover, Kretzoiarctos precedes in time the previously-known, Late Miocene members of the giant panda clade from Eurasia (Agriarctos and Ailurarctos). The former can be therefore considered the oldest recorded member of the giant panda lineage, which has significant implications for understanding the origins of this clade from a paleobiogeographic viewpoint.
www.researchgate.net/publication/233424489_Kretzoiarctos_gen_nov_the_Oldest_Member_of_the_Giant_Panda_Clade
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Post by brobear on Oct 7, 2021 9:36:53 GMT -5
Comparison:
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