To discover interordinal relationships of living and fossil placental mammals and the time of ori... more To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated with fossils, shows that crown clade Placentalia and placental orders originated after the K-Pg boundary. Many nodes discovered using molecular data are upheld, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Our tree suggests that Placentalia first split into Xenarthra and Epitheria; extinct New World species are the oldest members of Afrotheria.
The extratarsal spur in extant monotremes consists of an os calcaris and a cornu calcaris. A pois... more The extratarsal spur in extant monotremes consists of an os calcaris and a cornu calcaris. A poisonous extratarsal spur oc− curs only in the platypus (Ornithorhynchus); a possibly secondarily non−poisonous spur is present in echidnas (Tachy− glossus and Zaglossus). Some therian mammals (e.g., bats), reptiles (Chamaeleo), and amphibians have a spur−like struc− ture in the ankle, but this is not
A partial petrosal from the Upper Jurassic Morrison Formation of the Fruita Paleontological Area ... more A partial petrosal from the Upper Jurassic Morrison Formation of the Fruita Paleontological Area of western Colorado preserving the pars cochlearis and part of the pars canalicularis is described. The endocast of the inner ear showing the cochlea, vestibule, lateral semicircular canal, and the terminal ends of the anterior and posterior semicircular canals is reconstructed from µCT scans. This specimen is only the fourth petrosal known from the Morrison Formation. Mammals known from Fruita include Fruitafossor windsheffeli Luo and Wible, 2005, the triconodontid Priacodon fruitaensis Rasmussen and Callison, 1981, the plagiaulacoid multituberculate Glirodon grandis Engelmann and Callison, 1999, and unnamed spalacotheriids and dryolestoids. The partial petrosal and its endocast share significant features with dryolestoids from the Upper Jurassic of Guimarota, Portugal, including a separate fenestra cochleae and cochlear canaliculus, and a cochlea that is coiled more than 200°. In light of these similarities, the Fruita petrosal is assigned to Dryolestoidea.
To discover interordinal relationships of living and fossil placental mammals and the time of ori... more To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated with fossils, shows that crown clade Placentalia and placental orders originated after the K-Pg boundary. Many nodes discovered using molecular data are upheld, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Our tree suggests that Placentalia first split into Xenarthra and Epitheria; extinct New World species are the oldest members of Afrotheria.
The extratarsal spur in extant monotremes consists of an os calcaris and a cornu calcaris. A pois... more The extratarsal spur in extant monotremes consists of an os calcaris and a cornu calcaris. A poisonous extratarsal spur oc− curs only in the platypus (Ornithorhynchus); a possibly secondarily non−poisonous spur is present in echidnas (Tachy− glossus and Zaglossus). Some therian mammals (e.g., bats), reptiles (Chamaeleo), and amphibians have a spur−like struc− ture in the ankle, but this is not
A partial petrosal from the Upper Jurassic Morrison Formation of the Fruita Paleontological Area ... more A partial petrosal from the Upper Jurassic Morrison Formation of the Fruita Paleontological Area of western Colorado preserving the pars cochlearis and part of the pars canalicularis is described. The endocast of the inner ear showing the cochlea, vestibule, lateral semicircular canal, and the terminal ends of the anterior and posterior semicircular canals is reconstructed from µCT scans. This specimen is only the fourth petrosal known from the Morrison Formation. Mammals known from Fruita include Fruitafossor windsheffeli Luo and Wible, 2005, the triconodontid Priacodon fruitaensis Rasmussen and Callison, 1981, the plagiaulacoid multituberculate Glirodon grandis Engelmann and Callison, 1999, and unnamed spalacotheriids and dryolestoids. The partial petrosal and its endocast share significant features with dryolestoids from the Upper Jurassic of Guimarota, Portugal, including a separate fenestra cochleae and cochlear canaliculus, and a cochlea that is coiled more than 200°. In light of these similarities, the Fruita petrosal is assigned to Dryolestoidea.
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