''Podilymbus majusculus'' is an extinct species of

grebe Grebes () are aquatic diving birds in the order (biology), order Podicipediformes (). Grebes are widely distributed freshwater birds, with some species also found in sea, marine habitats during Bird migration, migration and winter. Most grebes f ...

recovered from the

Piacenzian The Piacenzian is in the international geologic time scale the upper stage (stratigraphy), stage or latest age (geology), age of the Pliocene. It spans the time between 3.6 ± 0.005 year#SI prefix multipliers, Ma and 2.58 Ma (million years ago). T ...

age of the United States.

History

The specimens were collected in the summer of 1965 from Idaho, United States by Claude W. Hibbard and the species was named in 1967 by Bertram G. Murray. The species name "majusculus" is Latin for "somewhat larger or greater", referring to the larger size of the species compared to the related pied-billed grebe (''P. podiceps'').

Description

The holotype material is a complete

tarsometatarsus The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bird bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) a ...

( UMMP 52470). The tarsometatarsus is similar in characteristic to the pied-billed grebe, but being larger in size. Compared to the recently extinct Atitlán grebe (''P. gigas''), the tarsometatarsus of ''P. majusculus'' is slender in width and longer. Other material that Murray (1967) can confidently identified belonging to ''P. majusculus'' is the anterior portion of the

sternum The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major bl ...

(UMMP 45277) and a

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

that is missing the proximal end (UMMP 52455). Both of these bone material are larger than any seen in pied-billed grebes. A complete

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

(UMMP 52536), a near complete femur (UMMP 52300), another femur with its distal portion (UMMP 49496), a proximal end of a femur (UMMP 49496), and a wornout but complete tarsometatarsus (UMMP 53703), and a possible complete

scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...

(UMMP 52672) have been also assigned to the species. Tibiotarsii recovered from the similarly aged Rexroad Formation and the Saw Rock Canyon Formation of Kansas have been tentatively assigned to this species (UMMP 51846 and UMMP 31716 respectively).

Classification

Classified in the genus ''

Podilymbus ''Podilymbus'' is a genus of birds in the Grebe family, the genus name is derived from Latin ''Podilymbus'', a contraction of ''podicipes'' ("feet at the buttocks", from ''podici-'', "rump-" + ''pes'', "foot")—the origin of the name of the gr ...

'', ''P. majusculus'' is the oldest known of the ''Podilymbus'' species.

Paleobiology

''P. majusculus'' is known from the

Glenns Ferry Formation The Glenns Ferry Formation is a Pliocene stratigraphic unit in the western United States. Outcrops of the formation in Hagerman Fossil Beds National Monument preserve the remains of seven fish species, five of which are extinct. These include the t ...

which the formation dates from the Piacenzian age of the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Aechmophorus elasson ''Aechmophorus elasson'' is an extinct species of grebe recovered from the Piacenzian age of the United States. History The specimens were collected in the summer of 1962 from Idaho, United States by Claude W. Hibbard and the species was named ...

'', another

Neogene The Neogene ( ,) is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period million years ago. It is the second period of th ...

grebe species. There is some size variation seen in the specimens where it is possible the larger ones are males and the smaller ones are females (as seen in the recent ''Podilymbus'' species).

References

{{Taxonbar, from=Q107349493 majusculus Fossil taxa described in 1967 Piacenzian species Birds described in 1967