Researchers have just finished their analysis of an organism known as Namacalathus hermanastes that lived between 549 and 542 mya (Late Ediacaran), that was found in the Nama Group of central and southern Namibia in Southern Africa, which has allowed them to trace the ancestry of some of the world's earliest animals further back than ever before and helps to further unravel a mystery concerning the origins of early animals that had vexed Darwin and became known as "Darwin's dilemma."
Until recently, not much was known about the origins of animals that evolved during the so-called "Cambrian Explosion" because of a lack of well-preserved fossils from that period, but the first three-dimensional preservation of soft tissue has established a strong evolutionary link between early Cambrian metazoans and one of their early ancestors from the Ediacaran (the pre-Cambrian geological period spanning some 94 million years from the end of the Cryogenian Period roughly 635 mya).
Prior to this new study conducted primarily by researchers from the University of Edinburgh, it was a difficult task to trace the links with earlier animals because their soft tissues (which provide vital details concerning an organisms ancestry) nearly always break down over time, especially when dealing with creatures this far back in time. But thanks to an x-ray imaging analysis of some remarkably well preserved soft tissues embedded in some iron pyrite (commonly known as "fool's gold"), the research team was able to compare them with those inside animals that evolved later in an attempt to establish any phylogenetic relationships of Namacalathus
And this analysis has revealed that Namacalathus is an ancestor of some types of molluscs and worms that later evolved during the Cambrian.
You can read the entire paper, Ediacaran metazoan reveals lophotrochozoan affinity and deepens root of Cambrian Explosion, by clicking on the provided hyperlink, but here is the abstract:
Until recently, not much was known about the origins of animals that evolved during the so-called "Cambrian Explosion" because of a lack of well-preserved fossils from that period, but the first three-dimensional preservation of soft tissue has established a strong evolutionary link between early Cambrian metazoans and one of their early ancestors from the Ediacaran (the pre-Cambrian geological period spanning some 94 million years from the end of the Cryogenian Period roughly 635 mya).
Prior to this new study conducted primarily by researchers from the University of Edinburgh, it was a difficult task to trace the links with earlier animals because their soft tissues (which provide vital details concerning an organisms ancestry) nearly always break down over time, especially when dealing with creatures this far back in time. But thanks to an x-ray imaging analysis of some remarkably well preserved soft tissues embedded in some iron pyrite (commonly known as "fool's gold"), the research team was able to compare them with those inside animals that evolved later in an attempt to establish any phylogenetic relationships of Namacalathus
And this analysis has revealed that Namacalathus is an ancestor of some types of molluscs and worms that later evolved during the Cambrian.
You can read the entire paper, Ediacaran metazoan reveals lophotrochozoan affinity and deepens root of Cambrian Explosion, by clicking on the provided hyperlink, but here is the abstract:
Abstract
Through exceptional preservation, we establish a phylogenetic connection between Ediacaran and Cambrian metazoans. We describe the first three-dimensional, pyritized soft tissue in Namacalathus from the Ediacaran Nama Group, Namibia, which follows the underlying form of a stalked, cup-shaped, calcitic skeleton, with six radially arranged lobes projecting into an apical opening and lateral lumens. A thick body wall and probable J-shaped gut are present within the cup, and the middle layer of the often-spinose skeleton and skeletal pores are selectively pyritized, supporting an organic-rich composition and tripartite construction with possible sensory punctae. These features suggest a total group lophotrochozoan affinity. These morphological data support molecular phylogenies and demonstrates that the origin of modern lophotrochozoan phyla, and their ability to biomineralize, had deep roots in the Ediacaran.
Through exceptional preservation, we establish a phylogenetic connection between Ediacaran and Cambrian metazoans. We describe the first three-dimensional, pyritized soft tissue in Namacalathus from the Ediacaran Nama Group, Namibia, which follows the underlying form of a stalked, cup-shaped, calcitic skeleton, with six radially arranged lobes projecting into an apical opening and lateral lumens. A thick body wall and probable J-shaped gut are present within the cup, and the middle layer of the often-spinose skeleton and skeletal pores are selectively pyritized, supporting an organic-rich composition and tripartite construction with possible sensory punctae. These features suggest a total group lophotrochozoan affinity. These morphological data support molecular phylogenies and demonstrates that the origin of modern lophotrochozoan phyla, and their ability to biomineralize, had deep roots in the Ediacaran.
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