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Eschrichtiidae or the gray whales is a family of baleen whale (suborder Mysticeti) with a single extant species, the gray whale (''Eschrichtius robustus''). The family, however, also includes three described fossil genera: ''Archaeschrichtius'' and ''Eschrichtioides'' from the Miocene and Pliocene of Italy respectively, and ''Gricetoides'' from the Pliocene of North Carolina. The names of the extant genus and the family honours Danish zoologist Daniel Eschricht. ==Taxonomic history== A number of 18th century authors〔E.g. ; ; 〕 described the gray whale as ''Balaena gibbosa'', the "whale with six bosses", apparently based on a brief note by : The gray whale was first described as a distinct species by based on a subfossil found in the brackish Baltic Sea, apparently a specimen from the now extinct north Atlantic population. Lilljeborg, however, identified it as "''Balaenoptera robusta''", a species of rorqual. realized that the rib and scapula of the specimen was different from those of any known rorquals, and therefore erected a new genus for it, ''Eschrichtius''. were convinced that the bones described by Lilljeborg could not belong to a living species but that they were similar to fossils that Van Beneden had described from the harbour of Antwerp (most of his named species are now considered nomina dubia) and therefore named the gray whale ''Plesiocetus robustus'', reducing Lilljeborg's and Gray's names to synonyms. produced one of the earliest descriptions of living Pacific gray whales, and notwithstanding that he was among the whalers who nearly drove them to extinction in the lagoons of the Baja California Peninsula, they were and still are associated with him and his description of the species. At this time, however, the extinct Atlantic population was considered a separate species (''Eschrischtius robustus'') from the living Pacific population (''Rhachianectes glaucus''). Things got increasingly confused as 19th century scientists introduced new species at an alarming rate (e.g. ''Eschrichtius pusillus'', ''E. expansus'', ''E. priscus'', ''E. mysticetoides''), often based on fragmentary specimens, and taxonomists started to use several generic and specific names interchangeably and not always correctly (e.g. ''Agalephus gobbosus'', ''Balaenoptera robustus'', ''Agalephus gibbosus''). Things got even worse in the 1930s when it was finally realised that the extinct Atlantic population was the same species as the extant Pacific population, and the new combination ''Eschrichtius gibbosus'' was proposed.〔 In his morphological analysis, found that eschrichtiids and Cetotheriidae (''Cetotherium'', ''Mixocetus'' and ''Metopocetus'') form a monophyletic sister group of Balaenopteridae. A specimen from the Late Pliocene of northern Italy, named ''"Cetotherium" gastaldii'' by and renamed ''"Balaenoptera" gastaldii'' by , was identified as a basal eschrichtiid by who recombined it to ''Eschrichtioides gastaldii''. 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Eschrichtiidae」の詳細全文を読む スポンサード リンク
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