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Nematoida
Nematoida is a clade of pseudocoelomate free living or parasitic animals. It consists of phyla Nematoda and Nematomorpha. The two groups share a number of features in common; the presence of a cloaca in both sexes, aflagellate sperm, and a cuticle made of collagen. Its position within Ecdysozoa Ecdysozoa () is a group of protostome animals, including Arthropoda (insects, chelicerates (including arachnids), crustaceans, and myriapods), Nematoda, and several smaller phylum (biology), phyla. The grouping of these animal phyla into a single ... is uncontroversial, but the identity of their closest relatives has been debated. Under the Cycloneuralia hypothesis, the nematoids are considered to be closest to Scalidophora, named for the ring-shaped brains found in these animals. However, this group has seen less support in phylogenetic analyses, with the Cryptovermes hypothesis being more consistently supported, which groups the nematoids with the panarthropods, although the issue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uncus Dzaugisi
''Uncus dzaugisi'' was a species of animal which lived approximately 560 to 550million years ago during the late Ediacaran in what is now Southern Australia. Its smooth cylindrical shape, with one end being wider than the other, suggests that it was a member of the clade Ecdysozoa (a group containing arthropods, nematodes and tardigrades, amongst others). This makes it the oldest ecdysozoan known so far, as well as one of the oldest known bilaterians. It is currently the only member of the genus ''Uncus''. Discovery and name The systematic excavation that led to the discovery of ''Uncus'' began in 2018 in the Ediacara Member, a Stratigraphic unit, rock unit of the Rawnsley Quartzite within the Nilpena Ediacara National Park, South Australia, which is known for its well preserved Ediacaran biota, Ediacaran fossils. During the excavation, the team, led by Mary Droser, noted the presence of deep, hook-shaped indentations in the rock. At first, they were not looked into with much ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecdysozoa
Ecdysozoa () is a group of protostome animals, including Arthropoda (insects, chelicerates (including arachnids), crustaceans, and myriapods), Nematoda, and several smaller phylum (biology), phyla. The grouping of these animal phyla into a single clade was first proposed by Eernisse ''et al.'' (1992) based on a phylogenetic analysis of 141 morphological characters of ultrastructural and embryological phenotypes. This clade, that is, a group consisting of a common ancestor and all its descendants, was formally named by Aguinaldo ''et al.'' in 1997, based mainly on phylogenetic trees constructed using 18S ribosomal RNA genes. A large study in 2008 by Dunn ''et al.'' strongly supported the monophyly of Ecdysozoa. The group Ecdysozoa is supported by many Morphology (biology), morphological characters, including growth by ecdysis, with moulting of the cuticle – without mitosis in the epidermis – under control of the prohormone ecdysone, and internal fertilization. The group was i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
