Pinnipedia

…The Creodonta, a Paleocene creodont genus once considered a suborder of Carnivora, has been found to be a separate order from Carnivora and has been considered an independent order in recent years. The Pinnipedia, a suborder consisting of about 34 species from the families Otariidae, Otariidae, and Phocidae, is often considered an independent order because its morphology and lifestyle are significantly different from those of the Pinnipedia suborder, but it is closely related to the families Ursidae and Mustelidae of the superfamily Ursoidea, and some experts even include it in this superfamily. All of the molars are the same shape and lack carnivorous teeth, the limbs have been modified into fins, the tail is short, and the ears and claws have degenerated. …

*Some of the terminology explanations that mention "Pinnipedia" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…かつて食肉類の1亜目とされていた暁新世の肉歯類Creodontaは，食肉目とは別系統のものと判明し，近年では独立の目とされる。　アシカ科，セイウチ科，アザラシ科の約34種からなる鰭脚亜目Pinnipediaは，形態や生活様式が裂脚亜目のものと顕著に異なるため，しばしば独立の目とされるが，クマ上科のクマ科やイタチ科に近縁で，この上科に含める専門家さえある。臼歯は皆同じ形で裂肉歯がなく，四肢はひれ状に変化し，尾が短く耳介とつめが退化している。…

※「Pinnipedia」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報