Palaeontologists have been developing some highly sophisticated tools for analysing fossil specimens. Of particular interest are techniques that probe the details of soft tissue preservation. In the research considered here, the 30 mm specimen was found at the Chengjiang lagerstatte locality in southwest China. It had large, claw-like appendages on its head and many jointed legs. It is assigned to the arthropods and thought to be a probable extinct chelicerate. It is referred to as one of the megacherian (meaning “great hand”) species with the genus name Alalcomenaeus. To analyse the soft tissues, a 3-D model of the specimen was produced using a CT-scanner and, at the same time, an X-ray microscope documented the distribution of selected chemical elements. In particular, iron has been found to map out the nervous system of the animal. The findings are spectacular.
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For more, go here.
The take-home message:
So we have the interesting situation that both groups of arthropods have neural patterns that are essentially modern. Whereas morphology is used to argue the case for “stem” and “crown” organisms, complex specified information is more readily discerned in soft tissues: genetic systems, developmental gene regulatory networks and neural patterns. Research over the past decade has indicated that numerous core genes are common to a large number of phyla with the implication being that they preceded the Cambrian Explosion of animal phyla (here and here). The same applies to developmental pathways. The research considered in this blog shows that the neural pathways for arthropods must be dated at least to the Early Cambrian. This provides an additional dimension to the Cambrian Explosion phenomenon – in that an extraordinary accumulation of biological information is already in place by the Middle Cambrian.
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