[D] Rahonavis ostromi [~/~]
Describer
Forster, Sampson, Chiappe & Krause, 1998
Time
Cretaceous Late Maastrichtian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae [Unnamed clade]
Fossilsite
Maevarano Formation,near Berivotra, Mahajanga Province, Madagascar
Info
Genus - Typespecies
First named Rahona but that name was first given to a Madagascar butterfly (Griveaud, 1976) so the name is replaced in Rahonavis.Although exhibiting avian features such as a reversed hallux and ulnar papillae, retains characteristics that indicate a theropod ancestry, including a pubic foot and hyposphene-hypantra vertebral articulations.
Rahonavis has a robust, hyperextendible second digit on the hind foot that terminates in a sicklelike claw, a unique characteristic of the theropod groups, Troodontidae and Dromaeosauridae. A phylogenetic analysis places Rahonavis with Archaeopteryx making Rahonavis one of the most primitive birds yet discovered. Like Archaeopteryx, Rahonavis retains a long bony tail.
Thirteen caudal vertebrae are preserved, but the complete number is unknown. The combination of morphological characters found in Rahonavis strongly supports its membership in Aves, as well as its theropod ancestry, and thus the dinosaurian origin of birds.
[Schweitzer, MH Watt, JA Avci, R Forster, CA Krause, DW Knapp, L Rogers, RR Beech, I Marshall, M, Journal of Vertebrate Paleontology, 1999, 19(4): 712]
Immunohistochemical studies, supported by additional lines of evidence, suggest that original proteinaceous components of keratin claw sheath material may be preserved in the pedal ungual phalanx associated with the primitive bird, Rahonavis ostromi, from the Late Cretaceous of Madagascar. This conclusion is based upon immunohistochemical analyses, and supported by brightfield, transmission, and scanning electron microscopy, mass spectrometry, and x-ray photoelectron spectroscopy.
Although keratinous structures such as hair, nails, claws, scales and feathers have been identified in the fossil record, these identifications were based on morphological similarity rather than molecular analyses. Chemical or immunological evidence for the survival of keratin has not previously been established in fossils older than similar to 33,000 BP.
This study demonstrates immunological staining and amino acid composition consistent with the presence of fragments of beta keratin, a protein family unique to reptiles and birds, in the specimen of Rahonavis ostromi.
Forster, Sampson, Chiappe & Krause, 1998
Time
Cretaceous Late Maastrichtian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae [Unnamed clade]
Fossilsite
Maevarano Formation,near Berivotra, Mahajanga Province, Madagascar
Info
Genus - Typespecies
First named Rahona but that name was first given to a Madagascar butterfly (Griveaud, 1976) so the name is replaced in Rahonavis.Although exhibiting avian features such as a reversed hallux and ulnar papillae, retains characteristics that indicate a theropod ancestry, including a pubic foot and hyposphene-hypantra vertebral articulations.
Rahonavis has a robust, hyperextendible second digit on the hind foot that terminates in a sicklelike claw, a unique characteristic of the theropod groups, Troodontidae and Dromaeosauridae. A phylogenetic analysis places Rahonavis with Archaeopteryx making Rahonavis one of the most primitive birds yet discovered. Like Archaeopteryx, Rahonavis retains a long bony tail.
Thirteen caudal vertebrae are preserved, but the complete number is unknown. The combination of morphological characters found in Rahonavis strongly supports its membership in Aves, as well as its theropod ancestry, and thus the dinosaurian origin of birds.
[Schweitzer, MH Watt, JA Avci, R Forster, CA Krause, DW Knapp, L Rogers, RR Beech, I Marshall, M, Journal of Vertebrate Paleontology, 1999, 19(4): 712]
Immunohistochemical studies, supported by additional lines of evidence, suggest that original proteinaceous components of keratin claw sheath material may be preserved in the pedal ungual phalanx associated with the primitive bird, Rahonavis ostromi, from the Late Cretaceous of Madagascar. This conclusion is based upon immunohistochemical analyses, and supported by brightfield, transmission, and scanning electron microscopy, mass spectrometry, and x-ray photoelectron spectroscopy.
Although keratinous structures such as hair, nails, claws, scales and feathers have been identified in the fossil record, these identifications were based on morphological similarity rather than molecular analyses. Chemical or immunological evidence for the survival of keratin has not previously been established in fossils older than similar to 33,000 BP.
This study demonstrates immunological staining and amino acid composition consistent with the presence of fragments of beta keratin, a protein family unique to reptiles and birds, in the specimen of Rahonavis ostromi.