Abstract:
Changes in predator-prey interactions are often implicated as drivers of major evolutionary change. A prominent example is the dramatic changes in shallow marine assemblages during the Mesozoic Marine Revolution (MMR) when major clades, including rhynchonelliform brachiopods, became restricted and less diverse. Currently, shallow-water temperate and polar brachiopods can be large, but in the tropics, they are small. By contrast, we demonstrate that throughout the Jurassic large brachiopods occurred in shallow sites, from polar to tropical latitudes, but are absent in later periods from tropical areas. These changes occurred in parallel in both major orders (Rhynchonellida and Terebratulida) and also independently within the two sub-ordinal lineages within the Terebratulida (terebratulinids and terebratellinids). Increases in both grazing and predation pressures associated with the MMR might account for this pattern. However, we note that many current environments support both large brachiopods and high densities of grazing species and suggest that the pattern fits more closely to the intensification of durophagous predation in shallow tropical waters.
摘要:
捕食者-猎物相互作用的变化通常被认为是重大进化变化的驱动因素。一个突出的例子是中生代海洋革命(MMR)期间浅海组合的巨大变化,包括钩状腕足动物,变得受限制和不那么多样化。目前,浅水温带和极地腕足动物可以很大,但在热带地区,它们很小。相比之下,我们证明,整个侏罗纪大型腕足动物都发生在浅层地点,从极地到热带纬度,但在热带地区的后期不存在。这些变化在两个主要顺序(Rhynchonellida和Terebratulida)中同时发生,并且在Terebratulida内的两个子顺序谱系(terebratulinids和terebratellinids)中也独立发生。与MMR相关的放牧和捕食压力的增加可能是这种模式的原因。然而,我们注意到,目前的许多环境都支持大型腕足动物和高密度的放牧物种,并表明这种模式更适合热带浅水中双重捕食的加剧。