''Enaliornis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of hesperornithine which lived during the late

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

to the early

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

, making them the oldest known hesperornithines. Fossils have been found near

Cambridge Cambridge ( ) is a List of cities in the United Kingdom, city and non-metropolitan district in the county of Cambridgeshire, England. It is the county town of Cambridgeshire and is located on the River Cam, north of London. As of the 2021 Unit ...

, England. Due to its lack of certain hesperornithid

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ha ...

ies, they were much more "conventional" birds and were initially held to be Gaviiformes (loons/divers).

Description

Based on the remnants that have been studied, it has not been determined if these birds had teeth like the others from this order. However, they were believed to not have well-developed wings. Like other hesperornithines, they probably had lobed feet for swimming, rather than webbed feet.Lim, J. D., Zhou, Z., Martin, L. D., Baek, K. S., & Yang, S. Y. (2000). The oldest known tracks of web-footed birds from the Lower Cretaceous of South Korea. ''Naturwissenschaften'', 87(6), 256-259.

Classification

''Enaliornis'' was originally named '' Pelagornis'' ("sea bird") by Seeley in 1866, but that name was preoccupied by a

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

bird related to the

pelican Pelicans (genus ''Pelecanus'') are a genus of large water birds that make up the family Pelecanidae. They are characterized by a long beak and a large throat pouch used for catching prey and draining water from the scooped-up contents before ...

s. Three species have been described: the small ''Enaliornis sedgwicki'', the medium-sized ''Enaliornis seeleyi'', and the large ''Enaliornis barretti''. The size of the largest of the three species was comparable to a large

pigeon Columbidae is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with small heads, relatively short necks and slender bills that in some species feature fleshy ceres. ...

.Perrins, C. (1987) Together, they are the only birds currently assigned to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Enaliornithidae. The presumed hesperornithine '' Potamornis'' from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

Lance Formation of Buck Creek (United States) may also be related to this group.

Relationships

In 2015, a species-level phylogenetic analysis found the following relationships among hesperornitheans.

References

Sources

* * * Cretaceous birds of Europe Hesperornithes Bird genera {{paleo-bird-stub