Balaenula

Balaenula is an extinct genus of cetacean .

Balaenula
Temporal range: Pliocene
Balaenula balaenopsis
Balaenula balaenopsis skeleton
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Balaenidae
Genus: Balaenula
van Beneden, 1872

Taxonomy

Cladistic analyses of fossils and extant balaenids place Balaenula as the sister taxon of right whales in a clade separate from the bowhead whale.[1][2]

Fossil records

This genus is known in the fossil records from the Neogene to the Quaternary (age range: from 11.608 to 1.806 million years ago). Fossils are found in the marine strata of Italy, United Kingdom, United States, the Netherlands, France and Japan.[1][3][4]

The most complete specimen known from the U.S.[5] (as well as the only one on display in North America[6]) was found at Lake Waccamaw, North Carolina in 2008. The whale's skull was excavated from the limestone outcropping by the state's Underwater Archaeology Branch, prepared, and permanently displayed at the Lake Waccamaw Depot Museum starting 2012.[7]

Species

Balaenidae - Balaenula astensis
Fossil skull and mandibles of Balaenula astensis from Portacomaro (Asti)

There are two currently recognized species of Balaenula:[4]

Balaenula astensis was quite similar to the living right whale (Eubalaena glacialis) but much smaller, reaching a length of about 5 metres (16 ft). This ancient mysticete lived about four million years ago. Fossils have been found near Asti (Northern Italy), in a Zanclean/Piacenzian marine sandstone.[4]

An unnamed species from Japan (represented by a partial skeleton) is also known.[10]

References

  1. ^ a b M. Bisconti. 2003. Evolutionary history of Balaenidae. Craniium 20(1):9-50
  2. ^ Churchill, M., Berta, A. and Deméré, T. (2012), The systematics of right whales (Mysticeti: Balaenidae). Marine Mammal Science, 28: 497–521. doi:10.1111/j.1748-7692.2011.00504.x
  3. ^ Marx, F. G. (2010). "The More the Merrier? A Large Cladistic Analysis of Mysticetes, and Comments on the Transition from Teeth to Baleen". Journal of Mammalian Evolution. 18 (2): 77–100. doi:10.1007/s10914-010-9148-4.
  4. ^ a b c Paleobiology Database
  5. ^ ncstateparks (2012-08-29). "Prehistoric Whale Gets a Home at Lake Waccamaw State Park". North Carolina State Parks. Retrieved 2016-05-31.
  6. ^ altondooley (2012-08-26). "Lake Waccamaw exhibit". Updates from the Paleontology Lab. Retrieved 2016-05-31.
  7. ^ "Lake Waccamaw State Park to Dedicate Exhibit of Rare Whale Fossil | NC State Parks". www.ncparks.gov. Retrieved 2016-05-31.
  8. ^ P. J. Van Beneden. 1872. Les Baleines fossiles d'Anvers. Bulletins de L'Academie Royale des Sciences, des Lettres et des Beaux-arts 34:6-23
  9. ^ L. Trevisan. 1942. Una nuova specie de Balaenula pliocenica. Palaeontogrphia Italica 40:1-13
  10. ^ M. Oishi and Y. Hasegawa. 1995. A list of fossil cetaceans in Japan. The Island Arc 3:493-505
Balaenidae

Balaenidae is a family of whales of the parvorder Mysticeti that contains two living genera: the right whales (genus Eubalaena), and in a separate genus, the closely related bowhead whale (genus Balaena).

Balaenula balaenopsis

Balaenula balaenopsis is an extinct species of right whale in the genus Balaenula. It was discovered in Belgium in the late 1800s. There is only one known specimen.

Baleen whale

Baleen whales (systematic name Mysticeti), known earlier as whalebone whales, form a parvorder of the infraorder Cetacea (whales, dolphins and porpoises). They are a widely distributed and diverse parvorder of carnivorous marine mammals. Mysticeti comprise the families Balaenidae (right and bowhead whales), Balaenopteridae (rorquals), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the gray whale). There are currently 15 species of baleen whales. While cetaceans were historically thought to have descended from mesonychids, (which would place them outside the order Artiodactyla), molecular evidence supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago.

Baleen whales range in size from the 20 ft (6 m) and 6,600 lb (3,000 kg) pygmy right whale to the 102 ft (31 m) and 190 t (210 short tons) blue whale the largest known animal to have ever existed. They are sexually dimorphic. Baleen whales can have streamlined or large bodies, depending on the feeding behavior, and two limbs that are modified into flippers. Though not as flexible and agile as seals, baleen whales can swim very fast, with the fastest able to travel at 23 miles per hour (37 km/h). Baleen whales use their baleen plates to filter out food from the water by either lunge-feeding or skim-feeding. Baleen whales have fused neck vertebrae, and are unable to turn their head at all. Baleen whales have two blowholes. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water.

Although baleen whales are widespread, most species prefer the colder waters of the Arctic and Antarctic. Gray whales are specialized for feeding on bottom-dwelling crustaceans. Rorquals are specialized at lunge-feeding, and have a streamlined body to reduce drag while accelerating. Right whales skim-feed, meaning they use their enlarged head to effectively take in a large amount of water and sieve the slow-moving prey. Males typically mate with more than one female (polygyny), although the degree of polygyny varies with the species. Male strategies for reproductive success vary between performing ritual displays (whale song) or lek mating. Calves are typically born in the winter and spring months and females bear all the responsibility for raising them. Mothers fast for a relatively long period of time over the period of migration, which varies between species. Baleen whales produce a number of vocalizations, notably the songs of the humpback whale.

The meat, blubber, baleen, and oil of baleen whales have traditionally been used by the indigenous peoples of the Arctic. Once relentlessly hunted by commercial industries for these products, cetaceans are now protected by international law. However, the North Atlantic right whale is ranked endangered by the International Union for Conservation of Nature. Besides hunting, baleen whales also face threats from marine pollution and ocean acidification. It has been speculated that man-made sonar results in strandings. They have rarely been kept in captivity, and this has only been attempted with juveniles or members of one of the smallest species.

List of extinct cetaceans

The list of extinct cetaceans features the extinct genera and species of the order Cetacea. The cetaceans (whales, dolphins and porpoises) are descendants of land-living mammals, the even-toed ungulates. The earliest cetaceans were still hoofed mammals. These early cetaceans became gradually better adapted for swimming than for walking on land, finally evolving into fully marine cetaceans.

This list currently includes only fossil genera and species. However, the Atlantic population of gray whales (Eschrichtius robustus) became extinct in the 18th century, and the baiji (or Chinese river dolphin, Lipotes vexillifer) was declared "functionally extinct" after an expedition in late 2006 failed to find any in the Yangtze River.

List of the Cenozoic life of California

This list of the Cenozoic life of California contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of California and are between 66 million and 10,000 years of age.

List of the Cenozoic life of North Carolina

This list of the Cenozoic life of North Carolina contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of North Carolina and are between 66 million and 10,000 years of age.

List of the prehistoric life of California

This list of the prehistoric life of California contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of California.

List of the prehistoric life of North Carolina

This list of the prehistoric life of North Carolina contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of North Carolina.

Pelagornithidae

The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dating between the Late Paleocene and the Pliocene-Pleistocene boundary.Most of the common names refer to these birds' most notable trait: tooth-like points on their beak's edges, which unlike true teeth contained Volkmann's canals and were outgrowths of the premaxillary and mandibular bones. Even "small" species of pseudotooth birds were the size of albatrosses; the largest ones had wingspans estimated at 5–6 metres (15–20 ft) and were among the largest flying birds ever to live. They were the dominant seabirds of most oceans throughout most of the Cenozoic, and modern humans apparently missed encountering them only by a tiny measure of evolutionary time: the last known pelagornithids were contemporaries of Homo habilis and the beginning of the history of technology.

Protororqualus

Protororqualus is a genus of extinct rorqual from the late Pliocene (Piacenzian, 3.6 to 2.6 Ma) of Mount Pulgnasco, Italy (45.1°N 9.7°E / 45.1; 9.7: paleocoordinates 45.0°N 9.6°E / 45.0; 9.6).The analysis made by Bisconti 2007 identified Protororqualus as a late representative of the rorquals which survived in the Mediterranean at least until the late Pliocene. This would indicate that the Mediterranean basin played a vital role in preserving primitive rorquals while more derived forms established themselves in other oceans.

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.