Ecological and taphonomic significance of spatangoid spines: relationship between mode of occurrence and water temperature
スポンサーリンク
概要
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The mode of occurrence of spatangoid spines in bottom sediments from the Japan Sea was examined in relation to temperature conditions. The remains of four species, Echinocardium cordatum, Spatangus luetkeni, Moira lachesinella, and Brisaster latifrons, were identified by comparing collected spines from bottom sediments with the morphological features of complete spines from living spatangoids. The spines were separated into four fragment types according to their preservational state: 1) the proximal part (with base, without tip), 2) the shaft (without both base and tip), 3) the distal part (without base, with tip), and 4) the intact spine. The spines were mostly fragmented, and the shaft and distal parts were found in almost all samples. The occurrence of the proximal part was strongly controlled by water temperature; the proximal part was dominant in warm water (9 to 25℃) but was seldom found in sediments in cold water (2 to 10℃). The decay process of Schizaster lacunosus in the laboratory in artificial seawater at three different temperatures (5℃, 20℃, and 30℃) was also studied. The disarticulation rate of the spines was strongly controlled by temperature, with low temperature drastically delaying the disarticulation process. The low occurrence of the proximal part in cold water can be explained by the long-term attachment of the spine base to its tubercle, preventing the echinoid carcass from supplying the proximal spine part to the sediment.
- 日本古生物学会の論文
- 2008-06-30