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The Feeding Limbs and Nervous System of Fuxianhuia Protensa

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A new paper in Nature reports on the discovery of a fossil revealing one of the world’s earliest nervous system and limbs used for feeding. Reports the abstract,

The organization of the head provides critical data for resolving the phylogenetic relationships and evolutionary history of extinct and extant euarthropods. The early Cambrian-period fuxianhuiids are regarded as basal representatives of stem-group Euarthropoda, and their anterior morphology therefore offers key insights for reconstructing the ancestral condition of the euarthropod head. However, the paired post-antennal structures in Fuxianhuia protensa remain controversial; they have been interpreted as both ‘great appendages’ and as gut diverticulae. Here we describe Chengjiangocaris kunmingensis sp. nov. andFuxianhuia xiaoshibaensis sp. nov. from a new early Cambrian (Stage 3) fossil Lagerstätte in Yunnan, China. Numerous specimens of both species show a unique ‘taphonomic dissection’ of the anterodorsal head shield, revealing the cephalic organization in detail. We demonstrate the presence of a pair of specialized post-antennal appendages (SPAs) in the fuxianhuiid head, which attach at either side of the posteriorly directed mouth, behind the hypostome. Preserved functional articulations indicate a welldefined but restricted range of limb movement, suggestive of a simple type of sweep feeding. The organization of the SPAs in fuxianhuiids is incompatible with the (deutocerebral) anterior raptorial appendages of megacheirans, and argue against the presence of protocerebral limbs in the fuxianhuiids. The positions of the fuxianhuiid antennae and SPAs indicate that they are segmentally homologous to the deutocerebral and tritocerebral appendages of crown-group Euarthropoda respectively. These findings indicate that antenniform deutocerebral appendages with many podomeres are a plesiomorphic feature of the ancestral euarthropod head.

Check out the Science Daily press release, as well as the original paper.

"We needed a nervous system, therefore one appeared," he said, without the slightest appearance of nervousness. Mung
Strange, indeed, since whatever their provenance, happenstance would have it that they served a not-insignificant purpose, even in they wee critters. Axel
Strange that nervous systems had to begin somewhere. And then got inherited afterwards. My goodness, weirdness in the extreme. How fortunate that a scientist went out and searched, and found the fossil. timothya
What a beautiful design. Mapou

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