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Sebecid from Miocene of Hispaniola + Wautaugategu, new lizard from Miocene of Georgia (USA) + lizard and tuatara pineal gland + coelacanth cranial muscles
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Ben Creisler
May 2, 2025, 1:07:32 PMMay 2
to DinosaurMa...@googlegroups.com
Ben Creisler
Some recent non-dino papers:
Lázaro W. Viñola López, Jorge Velez-Juarbe, Philippe Münch, Juan N. Almonte Milan, Pierre-Olivier Antoine, Laurent Marivaux, Osvaldo Jimenez-Vasquez and Jonathan Bloch
A South American sebecid from the Miocene of Hispaniola documents the presence of apex predators in early West Indies ecosystems
Proceedings of the Royal Society B: Biological Sciences 292(2045): 20242891
doi: https://doi.org/10.1098/rspb.2024.2891
https://royalsocietypublishing.org/doi/10.1098/rspb.2024.2891
Free pdf:
https://royalsocietypublishing.org/doi/epdf/10.1098/rspb.2024.2891
The absence of terrestrial apex predators on oceanic islands led to the evolution of endemic secondary apex predators like birds, snakes and crocodiles, and loss of defence mechanisms among species. These patterns are well documented in modern and Quaternary terrestrial communities of the West Indies, suggesting that biodiversity there assembled similarly through overwater dispersal. Here, we describe fossils of a terrestrial apex predator, a sebecid crocodyliform with South American origins from the late Neogene of Hispaniola that challenge this scenario. These fossils, along with other putative sebecid specimens from Cuba and Puerto Rico, show that deep-time Caribbean ecosystems more closely resembled coeval localities in South America than those of today. We argue that Plio-Pleistocene extinction of apex predators in the West Indies resulted in mesopredator release and other evolutionary patterns traditionally observed on oceanic islands. Adaptations to a terrestrial lifestyle documented for sebecids and the chronology of West Indian fossils strongly suggest that they reached the islands in the Eocene–Oligocene through transient land connections with South America or island hopping. Furthermore, sebecids persisted in the West Indies for at least five million years after their extinction in South America, preserving the last populations of notosuchians yet recovered from the fossil record.
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http://zoobank.org/58ded940-9082-46ae-8023-4b5f1b01691e
The first unequivocal fossil of a tupinambine in North America is described on the basis of a single thoracic vertebra from a middle Miocene (Barstovian 2) paleocoastal deposit in southwestern Georgia, USA. Wautaugategu formidus n. gen. n. sp. is a mid- to large-bodied taxon with a unique mosaic of tupinambine features. Vertebral position of the fossil was determined both by qualitative and quantitative methods. This record is coeval with the warmest part of the Neogene, the Middle Miocene Climatic Optimum, when increased temperatures would have made the southeastern United Sates more habitable for this hyperthermic group of lizards. Although the arrival time of tupinambines into North America is still unclear, an increasing number of endemic South American reptiles, including the large-bodied iguanid Ctenosaura, dispersed as far North as Panama by the early Miocene before formation of the Panamanian Isthmus.
Ricardo D Romero and Flávio S J de Souza (2025)
Evolution of Pineal Nonvisual Opsins in Lizards and the Tuatara and Identification of Lepidopsin: A New Opsin Gene
Genome Biology and Evolution 17(5): evaf058
doi: https://doi.org/10.1093/gbe/evaf058
https://academic.oup.com/gbe/article/17/5/evaf058/8123238
Many lizards (Squamata), as well as the tuatara (Rhynchocephalia), are distinguished among vertebrate groups for the presence of the parietal eye, or “third eye”, a structure derived from the pineal complex containing a simplified retina with photoreceptor cells. The parietal eye expresses nonvisual opsins that differ from the visual opsin repertoire of the lateral eyes. These are pinopsin (OPNP), parapinopsin (OPNPP), and parietopsin (OPNPT), all being evolutionary close to visual opsins. Here, we searched over 60 lepidosaurian genomes for pineal nonvisual opsins to check for the evolutionary trajectory of these genes in reptiles. Unexpectedly, we identified a novel opsin gene, which we termed “lepidopsin” (OPNLEP), that is present solely in the genomes of the tuatara and most lizard groups but absent from other vertebrates. Remnants of the gene are found in the coelacanth and some ray-finned fishes, implying that OPNLEP is an ancient opsin that has been repeatedly lost during vertebrate evolution. We found that the tuatara and most lizards of the Iguania, Anguimorpha, Scincoidea, and Lacertidae clades, which possess a parietal eye, harbor all pineal opsin genes. Lizards missing the parietal eye, like geckos, teiids, and a fossorial amphisbaenian, lack most or all pineal nonvisual opsins. In summary, our survey of pineal nonvisual opsins reveals (i) the persistence of a previously unknown ancient opsin gene—OPNLEP—in lepidosaurians; (ii) losses of nonvisual opsins in specific lizard clades; and (iii) a correlation between the presence of a parietal eye and the genomic repertoire of pineal nonvisual opsins.
Aléssio Datovo and G. David Johnson (2025)
Coelacanths illuminate deep-time evolution of cranial musculature in jawed vertebrates
Science Advances 11(18): eadt1576(2025
DOI: 10.1126/sciadv.adt1576
doi: https://www.science.org/doi/10.1126/sciadv.adt1576
https://www.science.org/doi/10.1126/sciadv.adt1576
Free pdf:
https://www.science.org/doi/epdf/10.1126/sciadv.adt1576
Coelacanths are rare fishes that occupy a key evolutionary position in the vertebrate tree of life. Despite being exhaustively studied, we found that a substantial part of the knowledge on their cranial musculature was mistaken. Eleven previously reported coelacanth “muscles” are nonexistent, while three previously unknown muscle subdivisions and connections are found. These findings markedly affect our understanding of the deep-time cranial evolution of jawed vertebrates (gnathostomes). Only 13% of the previously identified myological evolutionary novelties for the major gnathostome lineages proved to be accurate, but several new ones are proposed. We show that low, moderate, and high levels of cranial muscle innovation characterized the emergence of lobe-finned (sarcopterygian), cartilaginous (chondrichthyan), and ray-finned (actinopterygian) fishes, respectively. The novelties in the latter group resulted in the evolution of a second active mechanism for the expansion of the oropharyngeal cavity, which was probably crucial for the predominance of suction feeding versus bite feeding in extant actinopterygians.
====
=====
Free pdf:
Lázaro W. Viñola López, Jorge Velez-Juarbe, Philippe Münch, Juan N. Almonte Milan, Pierre-Olivier Antoine, Laurent Marivaux, Osvaldo Jimenez-Vasquez and Jonathan Bloch
A South American sebecid from the Miocene of Hispaniola documents the presence of apex predators in early West Indies ecosystems
Proceedings of the Royal Society B: Biological Sciences 292(2045): 20242891
doi: https://doi.org/10.1098/rspb.2024.2891
https://royalsocietypublishing.org/doi/10.1098/rspb.2024.2891
Free pdf:
https://royalsocietypublishing.org/doi/epdf/10.1098/rspb.2024.2891
The absence of terrestrial apex predators on oceanic islands led to the evolution of endemic secondary apex predators like birds, snakes and crocodiles, and loss of defence mechanisms among species. These patterns are well documented in modern and Quaternary terrestrial communities of the West Indies, suggesting that biodiversity there assembled similarly through overwater dispersal. Here, we describe fossils of a terrestrial apex predator, a sebecid crocodyliform with South American origins from the late Neogene of Hispaniola that challenge this scenario. These fossils, along with other putative sebecid specimens from Cuba and Puerto Rico, show that deep-time Caribbean ecosystems more closely resembled coeval localities in South America than those of today. We argue that Plio-Pleistocene extinction of apex predators in the West Indies resulted in mesopredator release and other evolutionary patterns traditionally observed on oceanic islands. Adaptations to a terrestrial lifestyle documented for sebecids and the chronology of West Indian fossils strongly suggest that they reached the islands in the Eocene–Oligocene through transient land connections with South America or island hopping. Furthermore, sebecids persisted in the West Indies for at least five million years after their extinction in South America, preserving the last populations of notosuchians yet recovered from the fossil record.
****
News:
Giant croclike carnivore fossils found in the Caribbean
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Wautaugategu formidus gen. et sp. nov.
Jason R. Bourque & Edward L. Stanley (2025)
A tegu-like lizard (Teiidae, Tupinambinae) from the Middle Miocene Climatic Optimum of the southeastern United States
Journal of Paleontology (advance online publication)
doi: https://doi.org/10.1017/jpa.2024.89
https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/tegulike-lizard-teiidae-tupinambinae-from-the-middle-miocene-climatic-optimum-of-the-southeastern-united-states/4C29E0FBB18656555DDD90D008AF7946
Jason R. Bourque & Edward L. Stanley (2025)
A tegu-like lizard (Teiidae, Tupinambinae) from the Middle Miocene Climatic Optimum of the southeastern United States
Journal of Paleontology (advance online publication)
doi: https://doi.org/10.1017/jpa.2024.89
https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/tegulike-lizard-teiidae-tupinambinae-from-the-middle-miocene-climatic-optimum-of-the-southeastern-united-states/4C29E0FBB18656555DDD90D008AF7946
**
http://zoobank.org/58ded940-9082-46ae-8023-4b5f1b01691e
The first unequivocal fossil of a tupinambine in North America is described on the basis of a single thoracic vertebra from a middle Miocene (Barstovian 2) paleocoastal deposit in southwestern Georgia, USA. Wautaugategu formidus n. gen. n. sp. is a mid- to large-bodied taxon with a unique mosaic of tupinambine features. Vertebral position of the fossil was determined both by qualitative and quantitative methods. This record is coeval with the warmest part of the Neogene, the Middle Miocene Climatic Optimum, when increased temperatures would have made the southeastern United Sates more habitable for this hyperthermic group of lizards. Although the arrival time of tupinambines into North America is still unclear, an increasing number of endemic South American reptiles, including the large-bodied iguanid Ctenosaura, dispersed as far North as Panama by the early Miocene before formation of the Panamanian Isthmus.
====
Free pdf:
Ricardo D Romero and Flávio S J de Souza (2025)
Evolution of Pineal Nonvisual Opsins in Lizards and the Tuatara and Identification of Lepidopsin: A New Opsin Gene
Genome Biology and Evolution 17(5): evaf058
doi: https://doi.org/10.1093/gbe/evaf058
https://academic.oup.com/gbe/article/17/5/evaf058/8123238
Many lizards (Squamata), as well as the tuatara (Rhynchocephalia), are distinguished among vertebrate groups for the presence of the parietal eye, or “third eye”, a structure derived from the pineal complex containing a simplified retina with photoreceptor cells. The parietal eye expresses nonvisual opsins that differ from the visual opsin repertoire of the lateral eyes. These are pinopsin (OPNP), parapinopsin (OPNPP), and parietopsin (OPNPT), all being evolutionary close to visual opsins. Here, we searched over 60 lepidosaurian genomes for pineal nonvisual opsins to check for the evolutionary trajectory of these genes in reptiles. Unexpectedly, we identified a novel opsin gene, which we termed “lepidopsin” (OPNLEP), that is present solely in the genomes of the tuatara and most lizard groups but absent from other vertebrates. Remnants of the gene are found in the coelacanth and some ray-finned fishes, implying that OPNLEP is an ancient opsin that has been repeatedly lost during vertebrate evolution. We found that the tuatara and most lizards of the Iguania, Anguimorpha, Scincoidea, and Lacertidae clades, which possess a parietal eye, harbor all pineal opsin genes. Lizards missing the parietal eye, like geckos, teiids, and a fossorial amphisbaenian, lack most or all pineal nonvisual opsins. In summary, our survey of pineal nonvisual opsins reveals (i) the persistence of a previously unknown ancient opsin gene—OPNLEP—in lepidosaurians; (ii) losses of nonvisual opsins in specific lizard clades; and (iii) a correlation between the presence of a parietal eye and the genomic repertoire of pineal nonvisual opsins.
====
====
Free pdf:
Aléssio Datovo and G. David Johnson (2025)
Coelacanths illuminate deep-time evolution of cranial musculature in jawed vertebrates
Science Advances 11(18): eadt1576(2025
DOI: 10.1126/sciadv.adt1576
doi: https://www.science.org/doi/10.1126/sciadv.adt1576
https://www.science.org/doi/10.1126/sciadv.adt1576
Free pdf:
https://www.science.org/doi/epdf/10.1126/sciadv.adt1576
Coelacanths are rare fishes that occupy a key evolutionary position in the vertebrate tree of life. Despite being exhaustively studied, we found that a substantial part of the knowledge on their cranial musculature was mistaken. Eleven previously reported coelacanth “muscles” are nonexistent, while three previously unknown muscle subdivisions and connections are found. These findings markedly affect our understanding of the deep-time cranial evolution of jawed vertebrates (gnathostomes). Only 13% of the previously identified myological evolutionary novelties for the major gnathostome lineages proved to be accurate, but several new ones are proposed. We show that low, moderate, and high levels of cranial muscle innovation characterized the emergence of lobe-finned (sarcopterygian), cartilaginous (chondrichthyan), and ray-finned (actinopterygian) fishes, respectively. The novelties in the latter group resulted in the evolution of a second active mechanism for the expansion of the oropharyngeal cavity, which was probably crucial for the predominance of suction feeding versus bite feeding in extant actinopterygians.
***
NOTE: Ignore news stories about a coelacanth sighted off the coast of California--it's fake, probably AI created junk.
https://sharonahill.com/fake-california-coelacanth/
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