Data from: The Lilliput effect in crinoids at the end of the Oceanic Anoxic Event 2: a case study from Poland

The Cretaceous period (145-66 Ma) consists of several Oceanic Anoxic Events (120-80 Ma), stimulated by global greenhouse effects. The Oceanic Anoxic Event 2 (OAE2) occurred worldwide from the late Cenomanian to the early-middle Turonian, causing a significant faunal turn-over, mostly in marine biota pushing some species to the brink of extinction. Some organisms also underwent morphological changes, including reduction in size. This anoxic event drove other changes, e.g., habitats or strategy of life. Here, we show that stalkless crinoids (comatulids) from the Turonian of Poland adapted to unfavorable environmental conditions by reducing their body size. Furthermore, at the moment when environmental factors become favorable again, these crinoids regained their regular (pre-event) size. This phenomenon most probably illustrates the so-called “dwarfing” mode of the Lilliput Effect.

白垩纪（Cretaceous period）距今145至66 Ma，其间存在多起由全球温室效应触发的海洋缺氧事件（Oceanic Anoxic Events，OAE），发生时段为120至80 Ma。海洋缺氧事件2（Oceanic Anoxic Event 2, OAE2）于森诺曼阶（Cenomanian）晚期至土仑阶（Turonian）早中期在全球范围内发生，引发了显著的生物群更替，尤以海洋生物群受创最重，致使诸多物种濒临灭绝。部分生物还发生了形态学改变，包括体型缩小。此次缺氧事件还驱动了其他生态变化，例如栖息地与生存策略的调整。本研究显示，产自波兰土仑阶的无柄海百合（stalkless crinoids，comatulids）通过缩小体型以适应恶劣的环境条件；此外，当环境条件再度好转时，这些海百合恢复至事件发生前的正常体型。这一现象极有可能印证了所谓‘小人国效应（Lilliput Effect）’的体型缩小模式。