Cruschedula
Encyclopedia
Cruschedula is an enigmatic bird
genus considered to be nomen dubium
which consists of the single
species
Cruschedula revola.
The genus was first described by Florentino Ameghino
in his 1899 volume Sinopsis geológico-paleontológica. Suplemento. (Adiciones y correcciones.). The name was coined by Ameghino from a combination of the meaing "shin" and meaning "a small sheet of paper". The etymology of the specific epithet
is not clear, but possibly from the . The genus and species were described from a single partial bone which Ameghino considered to be a tarsometatarsus
section. The bone was found in beds of the Deseado Formation near San Jorge Gulf in Southern Patagonia
. Designated the holotype specimen it was added to the Bernardino Rivadavia Natural Sciences Museum
along with a large portion of Ameghino's fossil collections.
In his paper, Ameghino erected the family Cruschedulidae, however in his 1906 paper "Enumeracion de los Impennes Fosiles de Patagonia y de la Isla Seymour" he synonymized
the family into Cladornithidae. When described Ameghino envisioned the genus and the family Cladornithidae as a whole to have represented a group of extinct "dry-land" penguin
s. This was because the fossil, having been collected from an outcrop of the Deseado Formation, was thought to be similar to other penguin fossils Ameghino attributed to the same formation. The Deseado Formation preserved a terrestrial environment, and thus the presence of penguins was considered highly unusual.
The placement of Cruschedula as a penguin was not challenged until 1946 by eminent paleontologist George Gaylord Simpson
. After examining the holotype, Simpson concluded there were no distinguishable details that defined the bone as from a penguin, but did not have any opinion as to what bird group it may have belonged to. The fossil was again restudied in 1964 by Pierce Brodkorb
, who asserted the fossil to not be a tarsometatarsus
but rather the end of a scapula
. In his Catalogue of Fossil Birds Brodkorb placed the genus into the diurnal bird of prey
family Accipitridae
. This placement was followed by Simpson in his 1972 Conspectus of Patagonian fossil penguins However, the placement was rejected by Eduardo P. Tonni in his 1980 paper The present state of knowledge of the Cenozoic birds of Argentina where he considered the bone fragment upon which the genus was erected to be undiagnostic. This assessment was supported by Storrs L. Olson
in 1985, who quoted Tonni's assessment of the Cruschedula holotype as undiagnostic.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
genus considered to be nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
which consists of the single
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
Cruschedula revola.
The genus was first described by Florentino Ameghino
Florentino Ameghino
Florentino Ameghino was an Argentine naturalist, paleontologist, anthropologist and zoologist.Born in Luján, son of Italian immigrants, Ameghino was a self-taught naturalist, and focused his study on the lands of the southern Pampas...
in his 1899 volume Sinopsis geológico-paleontológica. Suplemento. (Adiciones y correcciones.). The name was coined by Ameghino from a combination of the meaing "shin" and meaning "a small sheet of paper". The etymology of the specific epithet
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
is not clear, but possibly from the . The genus and species were described from a single partial bone which Ameghino considered to be a tarsometatarsus
Tarsometatarsus
The tarsometatarsus is a bone that is found in the lower leg of certain tetrapods, namely birds.It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsal and metatarsal bones...
section. The bone was found in beds of the Deseado Formation near San Jorge Gulf in Southern Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
. Designated the holotype specimen it was added to the Bernardino Rivadavia Natural Sciences Museum
Bernardino Rivadavia Natural Sciences Museum
The Bernardino Rivadavia Natural Sciences Museum is a public museum located in the Caballito section of Buenos Aires, Argentina.-History and overview:...
along with a large portion of Ameghino's fossil collections.
In his paper, Ameghino erected the family Cruschedulidae, however in his 1906 paper "Enumeracion de los Impennes Fosiles de Patagonia y de la Isla Seymour" he synonymized
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
the family into Cladornithidae. When described Ameghino envisioned the genus and the family Cladornithidae as a whole to have represented a group of extinct "dry-land" penguin
Penguin
Penguins are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica. Highly adapted for life in the water, penguins have countershaded dark and white plumage, and their wings have become flippers...
s. This was because the fossil, having been collected from an outcrop of the Deseado Formation, was thought to be similar to other penguin fossils Ameghino attributed to the same formation. The Deseado Formation preserved a terrestrial environment, and thus the presence of penguins was considered highly unusual.
The placement of Cruschedula as a penguin was not challenged until 1946 by eminent paleontologist George Gaylord Simpson
George Gaylord Simpson
George Gaylord Simpson was an American paleontologist. Simpson was perhaps the most influential paleontologist of the twentieth century, and a major participant in the modern evolutionary synthesis, contributing Tempo and mode in evolution , The meaning of evolution and The major features of...
. After examining the holotype, Simpson concluded there were no distinguishable details that defined the bone as from a penguin, but did not have any opinion as to what bird group it may have belonged to. The fossil was again restudied in 1964 by Pierce Brodkorb
Pierce Brodkorb
Pierce Brodkorb , also stated as William Pierce Brodkorb, was an American ornithologist and paleontologist....
, who asserted the fossil to not be a tarsometatarsus
Tarsometatarsus
The tarsometatarsus is a bone that is found in the lower leg of certain tetrapods, namely birds.It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsal and metatarsal bones...
but rather the end of a scapula
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
. In his Catalogue of Fossil Birds Brodkorb placed the genus into the diurnal bird of prey
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
family Accipitridae
Accipitridae
The Accipitridae, one of the two major families within the order Accipitriformes , are a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-sized mammals, with a number feeding on carrion and a...
. This placement was followed by Simpson in his 1972 Conspectus of Patagonian fossil penguins However, the placement was rejected by Eduardo P. Tonni in his 1980 paper The present state of knowledge of the Cenozoic birds of Argentina where he considered the bone fragment upon which the genus was erected to be undiagnostic. This assessment was supported by Storrs L. Olson
Storrs L. Olson
Storrs Lovejoy Olson is an American biologist and ornithologist from the Smithsonian Institution. He is one of the world's foremost avian paleontologists....
in 1985, who quoted Tonni's assessment of the Cruschedula holotype as undiagnostic.