On 11/21/23 8:04 AM, erik simpson wrote:
> https://www.nature.com/articles/s41598-023-32057-x open access
>
> Abstract
>
> Comprising the oldest unequivocal dinosauromorphs in the fossil record, silesaurs play an important role in the Triassic radiation of dinosaurs. These reptiles provide the main source of information regarding the ancestral body plan of dinosaurs, as well as the basis for biogeographic models. Nevertheless, the co-occurrence of silesaurs and the oldest unequivocal dinosaurs is rare, which hampers reliable ecological inferences. Here we present the first species of silesaur from the oldest unequivocal dinosaur-bearing beds from Brazil. Amanasaurus nesbitti gen. et sp. nov. possesses a unique set of femoral traits among silesaurs, including the oldest occurrence of an anterior trochanter separated by the femoral shaft by a marked cleft. Its femoral length indicates that the new species rivals in size with most coeval dinosaurs. This find challenges the assumption that in faunas where silesaurs and unambiguous dinosaurs co-occurred, silesaurs were relatively smaller. Moreover, the presence of dinosaur-sized silesaurs within ecosystems with lagerpetids, sauropodomorphs and herrerasaurids reinforces the complex scenario regarding the early radiation of Pan-Aves. Silesaurs—independent of their phylogenetic position—persisted during most of the Triassic Period, with its plesiomorphic body size advancing through the dawn of dinosaurs, instead of silesaur lineages decrease in body size through time.
> Introduction
>
> Silesaurs are part of the wide Triassic radiation of archosaurs1,2. Most silesaurs are characterized by slender limbs and a “beak-like” projection from the anterior tip of the lower jaw3. Whereas these reptiles are present in the fossil record of Middle to Upper Triassic4,5,6,7,8, no records have been reported from Jurassic or younger strata9,10. Silesaurs are particularly interesting because of their close phylogenetic relationships with dinosaurs4,11,12, with several studies placing silesaurs as the closest evolutionary relatives of dinosaurs4,11,13. On the other hand, there are alternative hypotheses where silesaurs are recovered as members of Ornithischia9,10,14,15. This latter scenario supports two main models: (i) silesaurs are part of a monophyletic assemblage (i.e., wide Silesauridae) that is the sister group of “traditional/core ornithischians”14,15,16; or (ii) silesaurs are assembled in low-diversity clades representing a stem group leading to “traditional/core ornithischians”9,10. Despite the competing affinities of silesaurs, these reptiles are key taxa in order to understand the dawn of the avian stem lineage. Silesaurs are the oldest dinosauromorphs reported in the fossil record4,5, providing clues on the ancestral body plan and biogeography of the group. The Middle Triassic occurrences from Brazil, Tanzania, and Zambia support a gondwanan origin of silesaurs4,5, whereas during the Upper Triassic, the group was present in both, Gondwana17,18,19,20 and Laurasia7,21,22. Although restricted to Argentina and Brazil, the fossil record from South America is particularly rich. There are two species from Argentina: Lewisuchus admixtus23, from the early Carnian beds of Chañares Formation; and Ignotosaurus fragilis, from the late Carnian of the Ischigualasto Formation18. Regarding Brazil, there are two species too: Gamatavus antiquus8, from the Ladinian/early Carnian of Santa Maria Formation; and Sacisaurus agudoensis17, from the early Norian of Caturrita Formation. In addition, there is an unnamed silesaur reported from the mid-to-late Carnian beds of Santa Maria Formation24. This unnamed material is remarkable because it comes from the oldest unequivocal dinosaur-bearing beds worldwide25, providing evidence of the co-occurrence of distinct groups of Pan-Aves during this crucial moment. Unfortunately, the scarcity of silesaurs from these beds obscures our understanding of the ecological relationships between these groups. Here, we describe the first silesaur species from Carnian (Upper Triassic) beds from Brazil and discuss its role on the evolutionary history of the group.
Interesting. But it's amazing that material consisting entirely of the
distal end of one femur and the proximal end of another manages to make
it into Nature. They must have really sold that story.

On 11/21/23 10:06 AM, erik simpson wrote:
> On Tuesday, November 21, 2023 at 8:25:06 AM UTC-8, John Harshman wrote:
>> On 11/21/23 8:04 AM, erik simpson wrote:
>>> https://www.nature.com/articles/s41598-023-32057-x open access
>>>
>>> Abstract
>>>
>>> Comprising the oldest unequivocal dinosauromorphs in the fossil record, silesaurs play an important role in the Triassic radiation of dinosaurs. These reptiles provide the main source of information regarding the ancestral body plan of dinosaurs, as well as the basis for biogeographic models. Nevertheless, the co-occurrence of silesaurs and the oldest unequivocal dinosaurs is rare, which hampers reliable ecological inferences. Here we present the first species of silesaur from the oldest unequivocal dinosaur-bearing beds from Brazil. Amanasaurus nesbitti gen. et sp. nov. possesses a unique set of femoral traits among silesaurs, including the oldest occurrence of an anterior trochanter separated by the femoral shaft by a marked cleft. Its femoral length indicates that the new species rivals in size with most coeval dinosaurs. This find challenges the assumption that in faunas where silesaurs and unambiguous dinosaurs co-occurred, silesaurs were relatively smaller. Moreover, the presence of dinosaur-sized silesaurs within ecosystems with lagerpetids, sauropodomorphs and herrerasaurids reinforces the complex scenario regarding the early radiation of Pan-Aves. Silesaurs—independent of their phylogenetic position—persisted during most of the Triassic Period, with its plesiomorphic body size advancing through the dawn of dinosaurs, instead of silesaur lineages decrease in body size through time.
>>> Introduction
>>>
>>> Silesaurs are part of the wide Triassic radiation of archosaurs1,2. Most silesaurs are characterized by slender limbs and a “beak-like” projection from the anterior tip of the lower jaw3. Whereas these reptiles are present in the fossil record of Middle to Upper Triassic4,5,6,7,8, no records have been reported from Jurassic or younger strata9,10. Silesaurs are particularly interesting because of their close phylogenetic relationships with dinosaurs4,11,12, with several studies placing silesaurs as the closest evolutionary relatives of dinosaurs4,11,13. On the other hand, there are alternative hypotheses where silesaurs are recovered as members of Ornithischia9,10,14,15. This latter scenario supports two main models: (i) silesaurs are part of a monophyletic assemblage (i.e., wide Silesauridae) that is the sister group of “traditional/core ornithischians”14,15,16; or (ii) silesaurs are assembled in low-diversity clades representing a stem group leading to “traditional/core ornithischians”9,10. Despite the competing affinities of silesaurs, these reptiles are key taxa in order to understand the dawn of the avian stem lineage. Silesaurs are the oldest dinosauromorphs reported in the fossil record4,5, providing clues on the ancestral body plan and biogeography of the group. The Middle Triassic occurrences from Brazil, Tanzania, and Zambia support a gondwanan origin of silesaurs4,5, whereas during the Upper Triassic, the group was present in both, Gondwana17,18,19,20 and Laurasia7,21,22. Although restricted to Argentina and Brazil, the fossil record from South America is particularly rich. There are two species from Argentina: Lewisuchus admixtus23, from the early Carnian beds of Chañares Formation; and Ignotosaurus fragilis, from the late Carnian of the Ischigualasto Formation18. Regarding Brazil, there are two species too: Gamatavus antiquus8, from the Ladinian/early Carnian of Santa Maria Formation; and Sacisaurus agudoensis17, from the early Norian of Caturrita Formation. In addition, there is an unnamed silesaur reported from the mid-to-late Carnian beds of Santa Maria Formation24. This unnamed material is remarkable because it comes from the oldest unequivocal dinosaur-bearing beds worldwide25, providing evidence of the co-occurrence of distinct groups of Pan-Aves during this crucial moment. Unfortunately, the scarcity of silesaurs from these beds obscures our understanding of the ecological relationships between these groups. Here, we describe the first silesaur species from Carnian (Upper Triassic) beds from Brazil and discuss its role on the evolutionary history of the group.
>> Interesting. But it's amazing that material consisting entirely of the
>> distal end of one femur and the proximal end of another manages to make
>> it into Nature. They must have really sold that story.
> The Pop-sci article that called it to my attention (https://www.sci.news/paleontology/amanasaurus-nesbitti-12466.html)
> even has a portrait of the little monster (obviously not derived from this fragmentary specimen).
The "reconstruction" in the Nature article is just as odd. Presumably it
all comes from various other silesaurids. But separate chunks of femur
from separate individuals doesn't do much. One might also be skeptical
of the tree resulting from those data.

On Tuesday, November 21, 2023 at 11:05:44 AM UTC-8, John Harshman wrote:
> On 11/21/23 10:06 AM, erik simpson wrote:
> > On Tuesday, November 21, 2023 at 8:25:06 AM UTC-8, John Harshman wrote:
> >> On 11/21/23 8:04 AM, erik simpson wrote:
> >>> https://www.nature.com/articles/s41598-023-32057-x open access
> >>>
> >>> Abstract
> >>>
> >>> Comprising the oldest unequivocal dinosauromorphs in the fossil record, silesaurs play an important role in the Triassic radiation of dinosaurs. These reptiles provide the main source of information regarding the ancestral body plan of dinosaurs, as well as the basis for biogeographic models. Nevertheless, the co-occurrence of silesaurs and the oldest unequivocal dinosaurs is rare, which hampers reliable ecological inferences. Here we present the first species of silesaur from the oldest unequivocal dinosaur-bearing beds from Brazil. Amanasaurus nesbitti gen. et sp. nov. possesses a unique set of femoral traits among silesaurs, including the oldest occurrence of an anterior trochanter separated by the femoral shaft by a marked cleft. Its femoral length indicates that the new species rivals in size with most coeval dinosaurs. This find challenges the assumption that in faunas where silesaurs and unambiguous dinosaurs co-occurred, silesaurs were relatively smaller. Moreover, the presence of dinosaur-sized silesaurs within ecosystems with lagerpetids, sauropodomorphs and herrerasaurids reinforces the complex scenario regarding the early radiation of Pan-Aves. Silesaurs—independent of their phylogenetic position—persisted during most of the Triassic Period, with its plesiomorphic body size advancing through the dawn of dinosaurs, instead of silesaur lineages decrease in body size through time.
> >>> Introduction
> >>>
> >>> Silesaurs are part of the wide Triassic radiation of archosaurs1,2. Most silesaurs are characterized by slender limbs and a “beak-like” projection from the anterior tip of the lower jaw3. Whereas these reptiles are present in the fossil record of Middle to Upper Triassic4,5,6,7,8, no records have been reported from Jurassic or younger strata9,10. Silesaurs are particularly interesting because of their close phylogenetic relationships with dinosaurs4,11,12, with several studies placing silesaurs as the closest evolutionary relatives of dinosaurs4,11,13. On the other hand, there are alternative hypotheses where silesaurs are recovered as members of Ornithischia9,10,14,15. This latter scenario supports two main models: (i) silesaurs are part of a monophyletic assemblage (i.e., wide Silesauridae) that is the sister group of “traditional/core ornithischians”14,15,16; or (ii) silesaurs are assembled in low-diversity clades representing a stem group leading to “traditional/core ornithischians”9,10. Despite the competing affinities of silesaurs, these reptiles are key taxa in order to understand the dawn of the avian stem lineage. Silesaurs are the oldest dinosauromorphs reported in the fossil record4,5, providing clues on the ancestral body plan and biogeography of the group. The Middle Triassic occurrences from Brazil, Tanzania, and Zambia support a gondwanan origin of silesaurs4,5, whereas during the Upper Triassic, the group was present in both, Gondwana17,18,19,20 and Laurasia7,21,22. Although restricted to Argentina and Brazil, the fossil record from South America is particularly rich. There are two species from Argentina: Lewisuchus admixtus23, from the early Carnian beds of Chañares Formation; and Ignotosaurus fragilis, from the late Carnian of the Ischigualasto Formation18. Regarding Brazil, there are two species too: Gamatavus antiquus8, from the Ladinian/early Carnian of Santa Maria Formation; and Sacisaurus agudoensis17, from the early Norian of Caturrita Formation. In addition, there is an unnamed silesaur reported from the mid-to-late Carnian beds of Santa Maria Formation24. This unnamed material is remarkable because it comes from the oldest unequivocal dinosaur-bearing beds worldwide25, providing evidence of the co-occurrence of distinct groups of Pan-Aves during this crucial moment. Unfortunately, the scarcity of silesaurs from these beds obscures our understanding of the ecological relationships between these groups. Here, we describe the first silesaur species from Carnian (Upper Triassic) beds from Brazil and discuss its role on the evolutionary history of the group.
> >> Interesting. But it's amazing that material consisting entirely of the
> >> distal end of one femur and the proximal end of another manages to make
> >> it into Nature. They must have really sold that story.
> > The Pop-sci article that called it to my attention (https://www.sci.news/paleontology/amanasaurus-nesbitti-12466.html)
> > even has a portrait of the little monster (obviously not derived from this fragmentary specimen).
> The "reconstruction" in the Nature article is just as odd. Presumably it
> all comes from various other silesaurids. But separate chunks of femur
> from separate individuals doesn't do much. One might also be skeptical
> of the tree resulting from those data.

Is there any way to ascertain whether multiple fragments are from the same individual?

On 11/21/23 10:45 PM, Sight Reader wrote:
> On Tuesday, November 21, 2023 at 11:05:44 AM UTC-8, John Harshman wrote:
>> On 11/21/23 10:06 AM, erik simpson wrote:
>>> On Tuesday, November 21, 2023 at 8:25:06 AM UTC-8, John Harshman wrote:
>>>> On 11/21/23 8:04 AM, erik simpson wrote:
>>>>> https://www.nature.com/articles/s41598-023-32057-x open access
>>>>>
>>>>> Abstract
>>>>>
>>>>> Comprising the oldest unequivocal dinosauromorphs in the fossil record, silesaurs play an important role in the Triassic radiation of dinosaurs. These reptiles provide the main source of information regarding the ancestral body plan of dinosaurs, as well as the basis for biogeographic models. Nevertheless, the co-occurrence of silesaurs and the oldest unequivocal dinosaurs is rare, which hampers reliable ecological inferences. Here we present the first species of silesaur from the oldest unequivocal dinosaur-bearing beds from Brazil. Amanasaurus nesbitti gen. et sp. nov. possesses a unique set of femoral traits among silesaurs, including the oldest occurrence of an anterior trochanter separated by the femoral shaft by a marked cleft. Its femoral length indicates that the new species rivals in size with most coeval dinosaurs. This find challenges the assumption that in faunas where silesaurs and unambiguous dinosaurs co-occurred, silesaurs were relatively smaller. Moreover, the presence of dinosaur-sized silesaurs within ecosystems with lagerpetids, sauropodomorphs and herrerasaurids reinforces the complex scenario regarding the early radiation of Pan-Aves. Silesaurs—independent of their phylogenetic position—persisted during most of the Triassic Period, with its plesiomorphic body size advancing through the dawn of dinosaurs, instead of silesaur lineages decrease in body size through time.
>>>>> Introduction
>>>>>
>>>>> Silesaurs are part of the wide Triassic radiation of archosaurs1,2. Most silesaurs are characterized by slender limbs and a “beak-like” projection from the anterior tip of the lower jaw3. Whereas these reptiles are present in the fossil record of Middle to Upper Triassic4,5,6,7,8, no records have been reported from Jurassic or younger strata9,10. Silesaurs are particularly interesting because of their close phylogenetic relationships with dinosaurs4,11,12, with several studies placing silesaurs as the closest evolutionary relatives of dinosaurs4,11,13. On the other hand, there are alternative hypotheses where silesaurs are recovered as members of Ornithischia9,10,14,15. This latter scenario supports two main models: (i) silesaurs are part of a monophyletic assemblage (i.e., wide Silesauridae) that is the sister group of “traditional/core ornithischians”14,15,16; or (ii) silesaurs are assembled in low-diversity clades representing a stem group leading to “traditional/core ornithischians”9,10. Despite the competing affinities of silesaurs, these reptiles are key taxa in order to understand the dawn of the avian stem lineage. Silesaurs are the oldest dinosauromorphs reported in the fossil record4,5, providing clues on the ancestral body plan and biogeography of the group. The Middle Triassic occurrences from Brazil, Tanzania, and Zambia support a gondwanan origin of silesaurs4,5, whereas during the Upper Triassic, the group was present in both, Gondwana17,18,19,20 and Laurasia7,21,22. Although restricted to Argentina and Brazil, the fossil record from South America is particularly rich. There are two species from Argentina: Lewisuchus admixtus23, from the early Carnian beds of Chañares Formation; and Ignotosaurus fragilis, from the late Carnian of the Ischigualasto Formation18. Regarding Brazil, there are two species too: Gamatavus antiquus8, from the Ladinian/early Carnian of Santa Maria Formation; and Sacisaurus agudoensis17, from the early Norian of Caturrita Formation. In addition, there is an unnamed silesaur reported from the mid-to-late Carnian beds of Santa Maria Formation24. This unnamed material is remarkable because it comes from the oldest unequivocal dinosaur-bearing beds worldwide25, providing evidence of the co-occurrence of distinct groups of Pan-Aves during this crucial moment. Unfortunately, the scarcity of silesaurs from these beds obscures our understanding of the ecological relationships between these groups. Here, we describe the first silesaur species from Carnian (Upper Triassic) beds from Brazil and discuss its role on the evolutionary history of the group.
>>>> Interesting. But it's amazing that material consisting entirely of the
>>>> distal end of one femur and the proximal end of another manages to make
>>>> it into Nature. They must have really sold that story.
>>> The Pop-sci article that called it to my attention (https://www.sci.news/paleontology/amanasaurus-nesbitti-12466.html)
>>> even has a portrait of the little monster (obviously not derived from this fragmentary specimen).
>> The "reconstruction" in the Nature article is just as odd. Presumably it
>> all comes from various other silesaurids. But separate chunks of femur
>> from separate individuals doesn't do much. One might also be skeptical
>> of the tree resulting from those data.
>
> Is there any way to ascertain whether multiple fragments are from the same individual?
There's certainly a way to ascertain whether they aren't. In this case,
one seems a bit larger than the other.