Allometric heterochrony in the Pliocene-Pleistocene planktic foraminiferal clade Globoconella
Allometric heterochrony in the Pliocene-Pleistocene planktic foraminiferal clade Globoconella
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DOI：
10.1017/s0094837300011143
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发表时间：
1994
期刊：
影响因子：
2.7
通讯作者：
K. Wei
中科院分区：
文献类型：
--
作者：
K. Wei
对上新世-更新世浮游有孔虫Globorotalia (Globoconella) puncticulata-inflata丛的大小形状关系进行异速分析，揭示了该分支形态演化的几种异速模式。其祖先谱系为过模斜，在3.5 ~ 3.0 Ma之间表现为异时性的预位移模式，在3.0 ~ 2.7 Ma之间表现为加速模式。在Globoconella祖先种群的个体发育过程中，另一种不同的变形过程，即等长体型（hypermorphosis），发生在大约3.5 Ma，并产生了G. inflata谱系。其后代谱系（G. inflata）似乎采用了幼体发育的趋势，在个体发育的3.5 ~ 2.35 Ma期间延迟了新生儿阶段的开始，导致了一系列的转位异位。在2.4 ~ 1.73 Ma区间，异速速率向相反方向移动，表现出预位移趋势。演化停滞期为1.73 ~ 0.25 Ma。第三纪晚期（0.26 ~ 0.05 Ma）结束了暴胀龙谱系的最后演化阶段。其形态具有巨大的可塑性和波动性，这与个体发育时期的高度正异速生长和种史上的大范围转位异速生长有关。异时模态的主要变化与古海洋事件一致，表明Globoconella枝的形态演化受到古海洋条件变化的调节。
Allometric analysis of the size-shape relationships in the Pliocene-Pleistocene planktic foraminiferal Globorotalia (Globoconella) puncticulata-inflata plexus reveals several heterochronic modes underlying the morphological evolution of the clade. The ancestral lineage, G. puncticulata, is a peramorphocline, showing a pre-displacement mode of heterochrony between 3.5 Ma and 3.0 Ma and an acceleration mode from 3.0 to 2.7 Ma. A different peramorphosis process, isometric giantism (hypermorphosis), in the ontogeny of the ancestral stocks of Globoconella occurred at about 3.5 Ma and gave rise to the G. inflata lineage. The descendant lineage, G. inflata, appears to have adopted a paedomorphosis trend by delaying the onset of the neanic stage in ontogeny during the period of 3.5 to 2.35 Ma, resulting in a series of transposition allometries. During the interval of 2.4 to 1.73 Ma, the allometries shifted to the opposite direction, signifying a pre-displacement trend. Evolutionary stasis marks the evolution during 1.73 to 0.25 Ma. Neoteny concluded the final evolutionary stage of the G. inflata lineage during the latest Quaternary (0.26 to 0.05 Ma). The enormous plasticity and fluctuations in morphology of G. inflata are attributed to the highly positive allometric growth during the ontogeny and the wide-range transposing allometries in the phyletic history. The major changes in heterochronic mode coincide with paleoceanographic events, suggesting that the morphological evolution in the Globoconella clade has been modulated by changes in paleoceanographic conditions.