''Eobalaenoptera'' is an extinct genus of

baleen whale Baleen whales (), also known as whalebone whales, are marine mammals of the order (biology), parvorder Mysticeti in the infraorder Cetacea (whales, dolphins and porpoises), which use baleen plates (or "whalebone") in their mouths to sieve plankt ...

belonging to Balaenopteroidea.

Discovery and significance

''Eobalaenoptera'' was first described in June 2004 by researchers at the

Virginia Museum of Natural History The Virginia Museum of Natural History is the state's natural history museum located in Martinsville, Virginia founded in 1984. The museum has several different award-winning publications, is affiliated with the Smithsonian Institution, and has ...

from a partial skeleton found in 1990 in

Caroline County, Virginia Caroline County is a United States county located in the eastern part of the Commonwealth of Virginia. The northern boundary of the county borders on the Rappahannock River, notably at the historic town of Port Royal. The Caroline county se ...

, the site of a prehistoric ocean, in the middle

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 ...

Calvert Formation The Calvert Formation is a Formation (geology), geologic formation in Maryland, Virginia, and Delaware. It preserves fossils dating back to the early to middle Miocene, Miocene epoch of the Neogene Period (geology), period. It is one of the three ...

. The skeleton proved to have similar morphological characteristics to a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

whale Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...

s consisting of two modern

taxonomic 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme of classes (a taxonomy) and the allocation ...

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

—

Balaenopteridae Rorquals () are the largest clade, group of baleen whales, comprising the family (biology), family Balaenopteridae, which contains nine extant taxon, extant species in two genus, genera. They include the largest known animal that has ever lived, ...

(the

rorqual Rorquals () are the largest clade, group of baleen whales, comprising the family (biology), family Balaenopteridae, which contains nine extant taxon, extant species in two genus, genera. They include the largest known animal that has ever lived, ...

s) and

Eschrichtiidae Eschrichtiidae or the gray whales is a family (taxonomy), family of baleen whale (Parvorder Mysticeti) with a single extant species, the gray whale (''Eschrichtius robustus''), as well as four described fossil genera: ''Archaeschrichtius'' (Mioce ...

(a family with one surviving species, the

gray whale The gray whale (''Eschrichtius robustus''), also known as the grey whale,Britannica Micro.: v. IV, p. 693. is a baleen whale that migrates between feeding and breeding grounds yearly. It reaches a length of , a weight of up to and lives between ...

). The age of the Calvert Formation (14 million years) makes ''Eobalaenoptera'' the oldest-known member of Balaenopteroidea by three to five million years. It also considerably narrowed the gap between the earliest-known

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

record and estimated time of divergence of this clade from other baleen whales. Molecular clocks have put this divergence for balaenopteroids from other crown mysticetes by 15–20 million years. In their review of extant and fossil rorquals, Demere et al. (2005) questioned the balaenopteroid placement of ''Eobalaenoptera'', noting that the holotype lack substantial cranial material that could reinforce its original classification, preferring to treat the genus as Chaeomysticeti ''incertae sedis''.T. A. Demere, A. Berta and M. R. McGowen. 2005. The taxonomic and evolutionary history of modern balaenopteroid mysticetes. Journal of Mammalian Evolution 12(1/2):99-143.

Etymology

The genus name ''Eobalaenoptera'' reflects the similarities between this skeleton and species in the genus ''

Balaenoptera ''Balaenoptera'' () is a genus of rorquals containing eight extant species. ''Balaenoptera'' comprises all but two of the extant species in its family (the humpback whale and gray whale); the genus is currently polyphyletic, with the two aforemen ...

'' such as the

minke whale The minke whale (), or lesser rorqual, is a species complex of baleen whale. The two species of minke whale are the common (or northern) minke whale and the Antarctic (or southern) minke whale. The minke whale was first described by the Danish na ...

; ''eo-'' is a prefix meaning dawn. The species is named after Carter Harrison, a volunteer worker at the museum.

References

* Baleen whales Miocene cetaceans Monotypic prehistoric cetacean genera Fossil taxa described in 2004 Miocene mammals of North America {{Paleo-whale-stub