エラスモサウルス

📖 1. 概要

全長10.3mのうち首の長さだけで7.1m（頸椎72個）に達する代表的な長頸竜（首長竜）です。

🌐 Wikipedia 要約抜粋

Elasmosaurus is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, at about 80.6 to 77 million years ago. The first specimen was discovered in 1867 near Fort Wallace, Kansas, US, and was sent to the American paleontologist Edward Drinker Cope, who named it E. platyurus in 1868. The generic name means "thin-plate reptile", and the specific name means "flat-tailed". Cope originally reconstructed the skeleton of Elasmosaurus with the skull at the end of the tail, an error which was made light of by the paleontologist Othniel Charles Marsh, and became part of their "Bone Wars" rivalry. Only one incomplete Elasmosaurus skeleton is definitely known, consisting of a fragmentary skull, the spine, and now lost pectoral and pelvic girdles, and a single species is recognized today; other species are now considered invalid or have been moved to other genera. A fragmentary specimen from Germany may belong to this genus.

🦴 2. 体の構造と特徴

四枚のヒレ状の脚を水中で羽ばたくように動かして泳いでいました。

🔍 3. 化石記録と古生態

19世紀の古生物学界における「化石戦争（Bone Wars）」を象徴する標本です。

🇰🇷 4. 韓国との関わり

中生代の海生爬虫類における水中適応を説明する代表的な種です。