[D] Nanantius valifanovi [~/~]
Describer
Kurochkin, 1996
Time
Cretaceous Late Campanian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Enantiornithe [Alexornithidae]
Fossilsite
Barun Goyot Formation, Hermiin Tsav, Mongolia
Info
Gobipteryx minuta (Elzanowski, 1974) > Nanantius valifanovi (Kurochkin, 1996)
The partial skeleton described by Kurochkin (1996) as the holotype of Nanantius valifanovi (PIN-4492-1) includes portions of the rostral end of the premaxillae and dentaries as well as of the braincase and palate and 30 small eggshell fragments, however, is likely equivalent to Gobipteryx minuta (Chiappe). Furthermore, as the ‘‘Nanantius valifanovi’’ elements represent a disarticulated and heavily weathered subadult specimen (Kurochkin, 1996) and not an embryo within an egg, the taxonomic identification of the fossil eggs is uncertain.
Note
Hospitaleche, C.A. & Tambussil, C.P. (2004) Abstract Systematic revision of South American fossil Penguins (Sphenisciformes). Sixth International meeting of the Society of AVian Paleontology and Evolution, Quillan, France
Nanantius valifanovi, was described from Baruungoyot deposits of Hermiin Tsav on the basis of a fairly complete skeleton (Kurochkin, 1996). N. valifanovi appeared similar to Gobipteryx minuta on the basis of two rows of foramina in the mandible, but different in each bird. In addition, jaw bones of N. valifanovi differ from those Gobipteryx minuta in general thickness, a thin and sharp tomium (flat in Gobipteryx) and an appreciable groove on the dorsal premaxilla (absent in Gobipteryx). In the ventral symphysial part of the mandible of Gobipteryx there is a low smooth crest, which is absent in N. valifanovi.
Chiappe, Norell, Clark, 2001 described the skull of a new specimen (IGM-100/1011) of enantiornithine bird from the Djadokhta Formation, Ukhaa Tolgod site, Nemegt Depression, which they assigned to Gobipteryx minuta, and N. valifanovi was synonymzed with this species. Their analysis utilized more than 49 characters, concluding that all three birds were extremely similar. Our analysis of their description could not support their conclusions. We added 4 anambiguous characters to the 15 of Chiappe et al (2001), which were preserved in all three forms.
Gobipteryx minuta showed no similarity to either specimen 100/1011 or N. valifanovi in any of the 19 characters. 14 characters appear common for N. valifanovi and specimen 100/1011. N. valifanovi and specimen 100/1011 are distinguished on 5 characters. In another 29 characters of Chiappe et al. (2001) and 1 character chosen by us, which are not preserved in N. valifanovi,
Gobipteryx minuta and specimen 100/1011 are radically different in 21characters, and have only 9 characters in common. In another 4 characters comparison is complicated owing to unpreserved or uncertain condition in G. minuta. However, among these 4 characters, 2 are common to N. valifanovi and specimen 100/1011, 1 character differs between them, and 1 character is not preserved in N. valifanovi.
Thus, N. valifanovi and specimen 100/1011 demonstrate great similarity in 16 characters, differing only in 6 insignificant characters. Together they show substantial differences from Gobipteryx minuta. Only one conclusion is possible: specimen IGM-100/1011 represents a new species of the genus Nanantius, and Gobipteryx minuta must retain its generic and specific status. Furthermore, embryos from the elongate eggs from Hermiin Tsav do not belong to Gobipteryx minuta, and it is certainly not possible to call these eggs, in which the embryos were discovered, “gobipteryx eggs”. They all represent various enantiornithine birds of the family Alexornithidae Brodkorb, 1976.
Kurochkin, 1996
Time
Cretaceous Late Campanian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Enantiornithe [Alexornithidae]
Fossilsite
Barun Goyot Formation, Hermiin Tsav, Mongolia
Info
Gobipteryx minuta (Elzanowski, 1974) > Nanantius valifanovi (Kurochkin, 1996)
The partial skeleton described by Kurochkin (1996) as the holotype of Nanantius valifanovi (PIN-4492-1) includes portions of the rostral end of the premaxillae and dentaries as well as of the braincase and palate and 30 small eggshell fragments, however, is likely equivalent to Gobipteryx minuta (Chiappe). Furthermore, as the ‘‘Nanantius valifanovi’’ elements represent a disarticulated and heavily weathered subadult specimen (Kurochkin, 1996) and not an embryo within an egg, the taxonomic identification of the fossil eggs is uncertain.
Note
Hospitaleche, C.A. & Tambussil, C.P. (2004) Abstract Systematic revision of South American fossil Penguins (Sphenisciformes). Sixth International meeting of the Society of AVian Paleontology and Evolution, Quillan, France
Nanantius valifanovi, was described from Baruungoyot deposits of Hermiin Tsav on the basis of a fairly complete skeleton (Kurochkin, 1996). N. valifanovi appeared similar to Gobipteryx minuta on the basis of two rows of foramina in the mandible, but different in each bird. In addition, jaw bones of N. valifanovi differ from those Gobipteryx minuta in general thickness, a thin and sharp tomium (flat in Gobipteryx) and an appreciable groove on the dorsal premaxilla (absent in Gobipteryx). In the ventral symphysial part of the mandible of Gobipteryx there is a low smooth crest, which is absent in N. valifanovi.
Chiappe, Norell, Clark, 2001 described the skull of a new specimen (IGM-100/1011) of enantiornithine bird from the Djadokhta Formation, Ukhaa Tolgod site, Nemegt Depression, which they assigned to Gobipteryx minuta, and N. valifanovi was synonymzed with this species. Their analysis utilized more than 49 characters, concluding that all three birds were extremely similar. Our analysis of their description could not support their conclusions. We added 4 anambiguous characters to the 15 of Chiappe et al (2001), which were preserved in all three forms.
Gobipteryx minuta showed no similarity to either specimen 100/1011 or N. valifanovi in any of the 19 characters. 14 characters appear common for N. valifanovi and specimen 100/1011. N. valifanovi and specimen 100/1011 are distinguished on 5 characters. In another 29 characters of Chiappe et al. (2001) and 1 character chosen by us, which are not preserved in N. valifanovi,
Gobipteryx minuta and specimen 100/1011 are radically different in 21characters, and have only 9 characters in common. In another 4 characters comparison is complicated owing to unpreserved or uncertain condition in G. minuta. However, among these 4 characters, 2 are common to N. valifanovi and specimen 100/1011, 1 character differs between them, and 1 character is not preserved in N. valifanovi.
Thus, N. valifanovi and specimen 100/1011 demonstrate great similarity in 16 characters, differing only in 6 insignificant characters. Together they show substantial differences from Gobipteryx minuta. Only one conclusion is possible: specimen IGM-100/1011 represents a new species of the genus Nanantius, and Gobipteryx minuta must retain its generic and specific status. Furthermore, embryos from the elongate eggs from Hermiin Tsav do not belong to Gobipteryx minuta, and it is certainly not possible to call these eggs, in which the embryos were discovered, “gobipteryx eggs”. They all represent various enantiornithine birds of the family Alexornithidae Brodkorb, 1976.