リファレンス
Morphology and functotion of the mandibular muscles in some coleoid cephalopods.
Kear, A. J. (1994). Journal of the Marine Biological Association of the United Kingdom, 74(4), 801-822.
要旨
The functional morphology of the buccal mass of 23 species of cephalopod (Octopoda, 4 species; Teuthoidea, 17; Sepioidea, 2) was investigated by gross dissection, histology and observations on fresh preparations. Cephalopod beaks lack a joint or articulation point. The jaws slide and rotate around an area rather than a fixed point. During closing the superior mandibular muscle (SMM) provides the force of a bite and the largest movement vector, whilst the inferior mandibular muscle (IMM) acts to retract the upper beak, causing shearing action. Dorsal portions of the lateral mandibular muscles (LMM) flex the upper beak walls outwards, probably to accommodate the backwards sweep of the radula and buccal palps during closing. To open the beaks, the ventral portions of the lateral mandibular muscles pull the rear lateral walls of the two beaks towards each other, moving the lower beak back relative to the upper.
コメント
イカタコの新規形質関連で口器 (いわゆるカラストンビorクチバシ) 周辺の筋肉の構造を調べていたときに見つけた論文．正し残念ながら古いこともあってか全文は入手できず．今回はリファレンスと要旨のメモ．ただ要旨だけでも上部・下部・側方部の筋肉の働きが簡潔にまとめられていて，わかりやすい．それぞれ順に，噛むために最も大きな力を生じる，beakを閉じて剪断するのに働く，歯舌と連動した動きやbeakを開くために使われる，といった感じなのかな．もっと詳しい構造とか切片の画像とかも見てみたいので，この論文を引用している論文からさらに調べてみようかなぁ．
