scholarly journals A right whale (Mysticeti, Balaenidae) from the Pleistocene of Taiwan

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Cheng-Hsiu Tsai ◽  
Chun-Hsiang Chang

AbstractCurrent patterns of biological distribution result from the deep past. Of particular interest, some closely related species appear at high latitudes of both hemispheres, but not in between, a pattern known as antitropical distribution. However, the timing, pathway, and drivers of antitropical distributions remain mostly unknown. Here we describe a new fossil, a left tympanic bulla (part of the ear bones), from the Middle/Late Pleistocene (0.78–0.01 mya, but not excluding the possibility of Holocene in age, as the specimen was dredged from the sea bottom and the geological horizon remains uncertain) of Taiwan. The tympanic bulla is diagnostic in baleen whales, and this specimen shows morphological features that are identical to extant Eubalaena, including: relatively large size (the anteroposterior length is 117 mm); rectangular outline in medial view; short anterior lobe, judging from the remaining of the lateral furrow; squared anterior margin; prominent transverse crease on the involucrum; transversely compressed in anterior view; well-developed and rounded outer lip; and parallel involucral and main ridges. Although incomplete, the morphological characters and overall similarity to extant Eubalaena allow a reliable taxonomic assignment to Eubalaena sp. The occurrence of a Pleistocene Eubalaena on the southern margin of the western North Pacific is the first balaenid fossil evidence indicative of the biotic interchange between two hemispheres leading to the origin of antitropical distribution in the Pleistocene; alternatively, this specimen might merely represent an extra-limital record of the North Pacific Eubalaena. Furthermore, this find suggests that the Eubalaena interchange, being one of the largest species displaying antitropical distribution pairs in the history of life, likely took place along the western Pacific. Notably, this does not preclude the Eubalaena interchange from other routes, such as the eastern Pacific or the Atlantic Ocean, and future finds should test the scenario for the biotic interchange between Northern and Southern Hemispheres of Eubalaena.

Author(s):  
Takahisa Nemoto

Much attention has been paid to euphausiids or krill because of their value as indispensable food of baleen whales and commercially important fish both in the North Atlantic and North Pacific and more recently attempts to exploit euphausiids for human consumption were undertaken in the Antarctic, North Pacific and in the Norwegian fjords.


2018 ◽  
Vol 5 (4) ◽  
pp. 172336 ◽  
Author(s):  
Carlos Mauricio Peredo ◽  
Nicholas D. Pyenson

Living baleen whales, or Mysticeti, lack teeth and instead feed using keratinous baleen plates to sieve prey-laden water. This feeding strategy is profoundly different from that of their toothed ancestors, which processed prey using the differentiated dentition characteristic of mammals. The fossil record of mysticetes reveals stem members that include extinct taxa with dentition, illuminating the morphological states that preceded the loss of teeth and the subsequent origin of baleen. The relationships among stem mysticetes, including putative clades such as Mammalodontidae and Aetiocetidae, remain debatable. Aetiocetids are among the more species-rich clade of stem mysticetes, and known only from fossil localities along the North Pacific coastline. Here, we report a new aetiocetid, Salishicetus meadi gen. et sp. nov, from the late Oligocene of Washington State, USA. Salishicetus preserves a near-complete lower dentition with extensive occlusal wear, indicating that it processed prey using shearing cheek teeth in the same way as its stem cetacean ancestors. Using a matrix with all known species of aetiocetids, we recover a monophyletic Aetiocetidae, crownward of a basal clade of Mammalodontidae. The description of Salishicetus resolves phylogenetic relationships among aetiocetids, which provides a basis for reconstructing ancestral feeding morphology along the stem leading to crown Mysticeti.


2008 ◽  
Author(s):  
John Bannister

Whales are mysterious and fascinating creatures. Despite modern technology, their world is still largely unexplored and unknown. They can only be seen, or rather glimpsed, when they are near the sea surface, either from boats, or perhaps from shore, or underwater by divers. They also reach astonishing sizes – the blue whale, for example, can grow to 30 metres in length, equivalent to the height of a six-storey building, and can weigh more than 130 tonnes. Seven ‘Great Whales’ are found in the coastal waters surrounding Australia. These include six of the largest baleen whales – blue whale, fin whale, humpback whale, sei whale, Bryde’s whale and southern right whale – and the sperm whale, the largest toothed whale. This book provides a detailed account of these extraordinary mammals. As well as the seven Great Whales, a smaller species – the minke whale – is included because of its special interest to Australians. The book describes whales’ highly specialised mammalian structure and biology, and the history of people’s association with them, at first through legend and wonder, then whaling, and more recently whale watching. It also looks at their past and current status, and the conservation initiatives that are in place to protect them from existing or potential threats. With both historical and recent photographs, as well as an extensive glossary, Great Whales will be enjoyed by natural history enthusiasts, zoologists and students alike.


2020 ◽  
pp. 261-268
Author(s):  
James E. Scarff

This study develops preliminary estimates of total whaling-induced mortality of northern right whales in the 19th century North Pacificpelagic whale fishery. Best’s (1987) study of American whaling returns resulted in estimates of the total American catch of 14,480 and15,374 northern right whales during the period 1839-1909. The present study offers adjustment factors to estimate total mortality from thesecatch data. Quantitative data from 14 pelagic expeditions for northern right whales in the North Pacific from 1838-1860 and additionalanecdotal information about struck-but-lost animals is reviewed. On 12 voyages, 327 northern right whales were struck with harpoons, butonly 133 landed. Adjusted for the subsequent recovery of struck whales, this implies a ratio of 2.43 whales struck for each whale eventuallysecured and flensed by whaleships. Data from four voyages show that of 148 northern right whales struck with harpoons, 14 sank beforethey could be processed. From a sample of five voyages, 80 northern right whales were landed and 31 carcasses sank without being secured.During the height of pelagic whaling in the North Pacific, approximately 10% of the fleet was non-American, primarily French. Adjustingrecorded catch estimates for struck-but-lost mortality and non-American whaling yields preliminary estimates of total mortality in thisfishery in the range of 26,500-37,000 animals during the period 1839-1909. In the single decade of 1840-49, between 21,000-30,000northern right whales may have been killed in the North Pacific, Sea of Okhotsk and Bering Sea, representing about 80% of the northernright whales killed in this region during the period 1839-1909.


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