Paraptenodytes brodkorbi is a proposed, but possibly invalid, 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...

 of extinct 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...

. The bird was probably about the size of an King Penguin

King Penguin

The King Penguin is the second largest species of penguin at about , second only to the Emperor Penguin. There are two subspecies—A. p. patagonicus and A. p...

.

Known material is limited to a single humerus

Humerus

The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

, Early Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

 in age, found in the Patagonian Molasse Formation near Puerto San Julián

Puerto San Julián

Puerto San Julián, also known historically as Port St Julian, is a natural harbour in Patagonia in the Santa Cruz Province of Argentina located at . In the days of sailing ships it formed a stopping point, south of Puerto Deseado...

 in Santa Cruz Province

Santa Cruz Province (Argentina)

Santa Cruz is a province of Argentina, located in the southern part of the country, in Patagonia. It borders Chubut province to the north, and Chile to the west and south. To the east is the Atlantic Ocean...

, Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

. It exists as an unnumbered specimen in the collection of the Museo Argentino de Ciencias Naturales.

This taxon

Taxon

|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

 is the product of a nomenclatorial dispute. 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 1905 described some penguin bones which he though to be specifically distinct as Isotremornis nordenskjöldi: 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...

, a humerus, and a part of a femur

Femur

The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...

. Subsequently, the tarsometatarsus and the femur piece turned out to be from Paraptenodytes antarcticus. 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...

 (1946) and Pierce Brodkorb

Pierce Brodkorb

Pierce Brodkorb , also stated as William Pierce Brodkorb, was an American ornithologist and paleontologist....

 (1963) argued about whether the bones could all be considered syntypes or whether only the wrongly assigned tarsometatarsus was designated as the holotype

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

. Brodkorb argued for the latter, and Simpson "reluctantly" agreed; Isotremornis nordenskjöldi became a junior synonym of P. antarcticus. Thus, another name had to be given - and added to the already long and confusing list of valid and invalid fossil penguin taxa - to the distinct humerus of the new species Ameghino had thought he described. Tongue-in-cheek, Simpson (1972) dedicated the new binomen

Binomen

In zoological nomenclature, a binomen , is the two-part name of a species. The term was introduced in 1953, abolishing the previously used "binomial name" . A binomen consists of a generic name and a specific epithet...

 to Brodkorb. Acosta Hospitaleche (2005) considered the humerus to be assignable to Paraptenodytes robustus

Paraptenodytes robustus

Paraptenodytes robustus is the type species of the penguin genus Palaeospheniscus, which is known from fossils. It was medium-sized, an estimated 70–80 cm long in life ....

; Bertelli et al. (2006) disagree, but believe that it belongs into a different genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

.