[D] Ichthyornis tener [~/~]
Cretaceous Late Coniacian Santonian Campanian
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Ornithurae Cartinatae Ichtyornithiformes
Niobrara Chalk Formation, Kansas, US
Guildavis tener (Clarke, 2004) > Ichthyornis tener (Marsh, 1880)
Definition: ‘‘Guildavis’’ is defined (Clarke, 2004) as a stem-based name (de Queiroz and Gauthier, 1992) for the clade including all taxa/specimens more closely related to YPM 1760 (tener Marsh, 1880, holotype specimen) than to Ichthyornis dispar or the following internal specifiers of Aves (Gauthier and de Queiroz, 2001; see Introduction): [Vultur gryphus], [Struthio camelus] Linnaeus, 1758, [Tetrao (Tinamus) major] Gmelin, 1789, and Vultur gryphus Linnaeus, 1758.
‘‘Guildavis’’ is a combination of ‘‘Guild’’, for E. W. Guild, who collected collected the holotype of tener and internal specifier, YPM 1760, and ‘‘avis’’, the Latin for bird. tener Marsh, 1880 (converted species name)
The name ‘‘tener’’ Marsh, 1880 is converted and defined as the name for the species that includes YPM 1760 (see the Introduction of the Taxonomic Revision for the definition of ‘‘species’’ used). With its clade address (sensu Cantino et al., 1999), the converted name of this species is ‘‘Guildavis tener’’. The name ‘‘tener’’ was originally published in the combination ‘‘Ichthyornis tener’’ (Marsh, 1880).
A specimen indicated by Marsh as the holotype was never figured, described, or diagnosed. YPM 1760, a sacrum, was specified in the following way: ‘‘The type specimen (number 1760) of the present species Ichthyornis tener was found in 1879, by Mr. E. W. Guild in Wallace County, Kansas.’’ (Marsh, 1880: 198). The locality, date of collection, and collector are that of YPM 1760, which is comprised of the sacrum. However, a humerus (YPM 1738) was figured in Odontornithes (Marsh, 1880: pl. XXX, fig. with the name ‘‘Ichthyornis tener’’ applied to it and this figure is referenced under the heading ‘‘Ichthyornis tener’’ where the species is named (Marsh, 1880: 198). The specimen number of the humerus was not mentioned in the text (Marsh, 1880) as either the holotype or as referred to Ichthyornis tener, although another specimen (a coracoid; YPM 1766) was mentioned as referred (Marsh, 1880: 198). The humerus was collected by S. W. Williston in 1877 and, thus, does match the description of the intended type specimen.
Brodkorb (1967) listed YPM 1760, the specimen mentioned by Marsh (1880), as the holotype, but incorrectly described it as an isolated distal humerus. Presumably, Brodkorb (1967) thought that the figured distal humerus (YPM 1738) in Odontornithes (Marsh, 1880: pl. XXX, fig. , with the name ‘‘Ichthyornis tener’’ applied to it, was YPM 1760, as nowhere in the text is it mentioned that YPM 1760 is a sacrum. This confusion points to a fundamental taxonomic question: whether the name ‘‘tener’’ is available and, if so, if it is tied to the humerus figured (YPM 1738) and not to the sacrum (YPM 1760) Marsh (1880) designated as the holotype. Under the ICZN (International Commission on Zoological Nomenclature, 1999; the PhyloCode does not yet address species level names) the name ‘‘Ichthyornis tener’’ would be available; its publication satisfies the provisions of Articles 11 and 12.
However, it is less clear whether the name is tied to the figured humerus (the illustration clearly constituting an ‘‘indication’’ under Article 12.2.7; International Commission on Zoological Nomenclature, 1999) or the sacrum the specimen number of which is referred to explicitly as the holotype specimen and additionally specified by locality, collection, year, and collector.
Clarke, 2004, the explicit designation by Marsh (1880) of YPM 1760 as the holotype of tener was followed in the choice of the internal specifier for both ‘‘Guildavis’’ and ‘‘tener’’ and considered the valid name-bearing specimen under the ICZN (International Commission on Zoological Nomenclature, 1999). While the humerus is supported by morphological correspondence as a part of Ichthyornis dispar, the sacrum can be differentiated from Ichthyornis dispar and is placed in the phylogenetic analyses as more closely related to Aves than to Ichthyornis dispar. YPM 1760 consists solely of two fragments of a tiny sacrum. One fragment, from the anterior end, preserves the anterior articular surface and the three anteriormost ankylosed vertebrae. The second fragment is from the middle of the sacral series. It is crushed dorsoventrally and no morphologies could be discerned.
Locality and horizon
Marsh (1880: 198) mentioned that YPM 1760 was ‘‘found in 1879 by Mr. E. W. Guild in Wallace County, Kansas.’’ No locality information other than ‘‘Cretaceous, Kansas’’ is provided on the original label associated with the specimen. The humerus (YPM 1738), figured as Ichthyornis tener in Odontornithes (Marsh, 1880: pl. XXX, but never mentioned in the text as referred to Ichthyornis tener, was collected by S. W. Williston ‘‘near Monument Rock’’ two years earlier (i.e., in 1877). (Clarke, 2004)