Eschrichtiidae or the gray whales is a
family of
baleen whale (Parvorder
Mysticeti) with a single extant species, the
gray whale (Eschrichtius robustus), as well as three described fossil genera: Archaeschrichtius and Eschrichtioides from the
Miocene and
Pliocene of Italy respectively,[1] and Gricetoides from the Pliocene of North Carolina.[2] More recent phylogenetic studies have found this family to be invalid, with its members nesting inside the
Balaenopteridae.[3][4] The names of the extant genus and the family honours Danish zoologist
Daniel Eschricht.[5]
Steeman et al. 2009 found that the gray whale is phylogenetically distinct from rorquals and that previous morphological studies were correct in the conclusion that the evolution of gulp feeding was a single event in the rorqual lineage.[10] In contrast, multiple later studies found the gray whale to fall within the family Balaenopteridae, being more derived than the
minke whales but basal to all other members in the family, and reclassified it in Balaenopteridae; the
American Society of Mammalogists has followed this classification.[3][4][11]
Evolution
Fossils of Eschrichtiidae have been found in all major oceanic basins in the Northern Hemisphere, and the family is believed date back to the
Late Miocene.[8] Today, gray whales are only present in the northern Pacific, but a population was also present in the northern Atlantic before being driven to extinction by European whalers three centuries ago.[12]
Fossil eschrichtiids from before the Holocene are rare compared to other fossil mysticetes. The only Pleistocene fossil from the Pacific referred to E. eschrichtius is a partial skeleton and an associated skull from California, estimated to be about 200 thousand years old. However, a late Pliocene fossil from
Hokkaido, Japan, referred to Eschrichtius sp. is estimated to be 2.6 to 3.9 Mya and a similar unnamed fossil has been reported from California.[8]
In their description of Archaeschrichtius ruggieroi from the late Miocene of Italy,
Bisconti & Varola 2006 argued that eschrichtiids most likely originated in the
Mediterranean Basin about 10 million years ago and remained there, either permanently or intermittently, at least until the
Early Pliocene (5–3 Mya),[13] (but see
Messinian salinity crisis.)
Bisconti, M. (2008). "Morphology and phylogenetic relationships of a new eschrichtiid genus (Cetacea: Mysticeti) from the Early Pliocene of northern Italy". Zoological Journal of the Linnean Society. 153: 161–186.
doi:
10.1111/j.1096-3642.2008.00374.x.
OCLC438026086.
Bryant, P. J. (1995). "Dating Remains of Gray Whales from the Eastern North Atlantic". Journal of Mammalogy. 76 (3): 857–861.
doi:
10.2307/1382754.
JSTOR1382754.
Scammon, C. M. (1869). "On the cetaceans of the western coast of North America". Proceedings of the Academy of Natural Sciences of Philadelphia. 21: 13–63.
JSTOR4060095.
Scammon, C. M. (1874).
"The California Gray Whale". The marine mammals of the north-western coast of North America. San Franc.: John H. Carmany and Co. pp. 20–33.
Whitmore, F. C.; Kaltenbach, J. A. (2008). "Neogene Cetacea of the Lee Creek Phosphate Mine, North Carolina". Virginia Museum of Natural History Special Publication. 14: 181–269.