近期《自然》期刊發(fā)表了一項研究,，發(fā)現(xiàn)螯肢亞門（其下包括蜘蛛及蝎子）的神經(jīng)系統(tǒng)與已滅絕的大附肢綱（頭部伸出可怕呈爪狀肢體的古代生物）最相似。
大附肢綱屬已絕滅節(jié)肢動物，擁有現(xiàn)代動物沒有的龐大呈爪狀肢體,，其進(jìn)化歷程一直備受爭議,。中國昆明云南大學(xué)侯先光教授,、美國亞利桑那大學(xué)Nicholas Strausfeld教授與他們的團隊發(fā)現(xiàn)了一副保存完好,，屬于中國5.2億年前早寒武世時期的大附肢動物化石。他們重塑出此動物的神經(jīng)系統(tǒng),，包括頭部和軀干的神經(jīng)分節(jié),，這神經(jīng)系統(tǒng)是目前為止最完整的寒武世動物的神經(jīng)系統(tǒng)。結(jié)果表明,，大附肢綱酷似螯肢亞門,，其下包括蜘蛛,、蝎子及他們的近親。(生物谷Bioon.com)
生物谷推薦的英文摘要
Nature doi:10.1038/nature12520
Chelicerate neural ground pattern in a Cambrian great appendage arthropod
Gengo Tanaka,Xianguang Hou,Xiaoya Ma,Gregory D. Edgecombe& Nicholas J. Strausfeld
Preservation of neural tissue in early Cambrian arthropods has recently been demonstrated, to a degree that segmental structures of the head can be associated with individual brain neuromeres. This association provides novel data for addressing long-standing controversies about the segmental identities of specialized head appendages in fossil taxa. Here we document neuroanatomy in the head and trunk of a ‘great appendage’ arthropod, Alalcomenaeus sp., from the Chengjiang biota, southwest China, providing the most complete neuroanatomical profile known from a Cambrian animal. Micro-computed tomography reveals a configuration of one optic neuropil separate from a protocerebrum contiguous with four head ganglia, succeeded by eight contiguous ganglia in an eleven-segment trunk. Arrangements of optic neuropils, the brain and ganglia correspond most closely to the nervous system of Chelicerata of all extant arthropods, supporting the assignment of ‘great appendage’ arthropods to the chelicerate total group. The position of the deutocerebral neuromere aligns with the insertion of the great appendage, indicating its deutocerebral innervation and corroborating a homology between the ‘great appendage’ and chelicera indicated by morphological similarities. Alalcomenaeus and Fuxianhuia protensa demonstrate that the two main configurations of the brain observed in modern arthropods, those of Chelicerata and Mandibulata, respectively, had evolved by the early Cambrian.
