论文标题：An encrusting kleptoparasite-host interaction from the early Cambrian

期刊：Nature Communications

作者： Zhifei Zhang, Luke C. Strotz et al.

发表时间：2020/06/02

DOI：10.1038/s41467-020-16332-3

微信链接：点击此处阅读微信文章

根据本周《自然-通讯》发表的一篇论文An encrusting kleptoparasite-host interaction from the early Cambrian，动物在寒武纪大爆发（约5.41亿年前）后不久便需要与寄生虫作斗争。研究发现，古代腕足动物被一种生物寄生，后者或能将腕足动物的食物转为自食。这项发现标志着迄今已知在化石记录中发现的最古老的寄生关系。

乌龙箐新圆货贝和壳外覆有的一种管居生物。| credit: Zhang et al.

腕足动物是小型有壳的海洋动物，形似双壳类，现存约450种，但是化石记录显示存在逾12,000种。

中国西北大学的张志飞及同事分析了在云南发现的寒武纪腕足动物乌龙箐新圆货贝（Neobolus wulongqingensis）的化石种群，测定年份约为5.12亿年前。他们发现许多乌龙箐新圆货贝的壳外覆有一种管居生物，而覆有管居生物的乌龙箐新圆货贝体型明显较小，而且这些管状构造与腕足动物自身的摄食水流方向一致。因此，张志飞等人认为这种管居生物通过偷窃宿主的食物，削弱宿主的健康（偷窃寄生现象）。

寄生互作难以在化石记录中保存下来，因为大部分推断都需以外形为依据。在此，作者不仅收集到了罕见的寄生现象的外形证据，还发现了该寄生现象的成本。

摘要：

Parasite–host systems are pervasive in nature but are extremely difficult to convincingly identify in the fossil record. Here we report quantitative evidence of parasitism in the form of a unique, enduring life association between tube-dwelling organisms encrusted to densely clustered shells of a monospecific organophosphatic brachiopod assemblage from the lower Cambrian (Stage 4) of South China. Brachiopods with encrusting tubes have decreased biomass (indicating reduced fitness) compared to individuals without tubes. The encrusting tubes orient tightly in vectors matching the laminar feeding currents of the host, suggesting kleptoparasitism. With no convincing parasite–host interactions known from the Ediacaran, this widespread sessile association reveals intimate parasite–host animal systems arose in early Cambrian benthic communities and their emergence may have played a key role in driving the evolutionary and ecological innovations associated with the Cambrian radiation.

（来源：科学网）