Krassilov V., Shuklina S.
В журнале Alavesia
Год: 2008 Номер: 2 Страницы: 239-245
This study of parasitoid marks on leaf impressions (phyllostigmas) is based on fossil plant material from the Albian to Turonian of central and southern Negev. On account of widespread homeomorphy of phyllostigmatic structures produced by various organisms, their taxonomic assignments are but tentative emphasizing similarities of habits, evolution of which is recorded in the first place. The mid-Cretaceous phyllostigmas represent specialized habits of oviposition, external feeding, gall making and mining, their diversity being greatly enhanced by the advent of angiosperms. The Albian phyllostigmas mostly occur on gymnosperm leaves, the contemporaneous angiosperm leaves being infested with egg sets of Odonata alone, indicating a waterside habitat. Angiosperm leaves became more frequently stigmatized during the Cenomanian followed by the major diversification burst of parasitic arthropods in the mid-Turonian. The widespread occurrence of procecidia, the prevalence of organoid galls, some drastically damaging to the leaves, and of extensive blotch mining are evidence of a relatively low co-adaptation level in the mid-Cretaceous plant – arthropod communities. “Weakness parasitism” is suggested by the frequent on leaf co-occurrence of various phyllostigmas. At the same time, the first appearance of mine and gall predators might have invoked an incipient top-down regulation of parasitarian systems. In this respect, the coastal and inland plant – arthropod communities show different levels of evolutionary advancement.
