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The arthropod head problem has been tackled in three main ways in this regard, first by using genetic segmental markers to probe the obscure region in front of the mouth, especially in insects; second by looking at Hox gene expression patterns to detect patterns of homology among different arthropods; and third, by studying gene expression in ...
Nevertheless, despite being known from many specimens, disputes about its morphology, in particular its head appendages, have made it one of the most controversial of the Chengjiang taxa, and it has been discussed extensively in the context of the arthropod head problem. The genus is named after Fuxian Lake (Fuxian Hu), where it was unearthed.
In chelicerates and crustaceans, the cephalothorax is derived from the fusion of the cephalon and the thorax, and is usually covered by a single unsegmented carapace.In relation with the arthropod head problem, phylogeny studies show that members of the Malacostraca class of crustaceans have five segments in the cephalon, when not fused with the thorax to form a cephalothorax.
A lobster is heavily cephalized, with eyes, antennae, multiple mouthparts, and the brain (inside the armoured exoskeleton), all concentrated at the animal's head end. Cephalization is an evolutionary trend in animals that, over a sufficient number of generations, concentrates the special sense organs and nerve ganglia towards the front of the ...
Lyrarapax is a radiodont genus of the family Amplectobeluidae that lived in the early Cambrian period 520 million years ago. Its neural tissue indicates that the radiodont frontal appendage is protocerebral, resolving parts of the arthropod head problem and showing that the frontal appendage is homologous to the antennae of Onychophorans and labrum of euarthropods. [1]
The discovery of an intact Arthropleura head offers new insights. Researchers have wondered how an alligator-size arthropod lived more than 300 million years ago. The discovery of an intact ...
Unsolved problems relating to the structure and function of non-human organs, processes and biomolecules include: Korarchaeota (archaea). The metabolic processes of this phylum of archaea are so far unclear. Glycogen body. The function of this structure in the spinal cord of birds is not known. Arthropod head problem. A long-standing zoological ...
Egyptian and Qatari mediators were working to salvage the ceasefire deal between Israel and Hamas on Wednesday, according to Egypt’s state-run Al-Qahera News TV, which is close to the country's ...