Megarachne
Fossils of Megarachne have been discovered in deposits of Late Carboniferous age, from the Gzhelian stage, in San Luis, Argentina. If the original identification as a spider had been correct, Megarchne would have been the largest known spider to have ever lived. The fossil preserves the carapace, the first two tergites, three partial appendages and what is possibly a coxa.
About Megarachne in brief
Fossils of Megarachne have been discovered in deposits of Late Carboniferous age, from the Gzhelian stage, in San Luis, Argentina. The fossils of the single and type species M. servinei have been recovered from deposits that had once been a freshwater environment. If the original identification as a spider had been correct, Megarchne would have been the largest known spider to have ever lived. The fossil preserves the carapace, the first two tergites, three partial appendages and what is possibly a coxa. With an estimated length of 9 cm, the fossil was of a leg span of around 30 centimetres and a body length of 54 cm. It is the most complete eurypterid discovered in carboniferous deposits in South America so far. Some researchers have hypothesized that MegarACHne and two other members of its family, Mycterops and Woodwardopterus, represent different developmental stages of a single genus. The generic name, composed of the Ancient Greek meaning ‘great’ and Latin arachne means ‘spider’, translates to “great spider’.
The species would have raked through the soft sediment of aquatic environments in swamps and rivers with its frontal appendage blades to capture and feed on small invertebrates. The function of the second tergite, the function of which remains unknown, is also unknown. It was similar to other mycteroptids in appearance, a group distinguished from other myctoropoids by the parabolic shape of their prosoma, hastate telsons and paired keel-shaped projections on the underside, and heads with small compound eyes that were roughly trapezoidal in shape. Although large for an arthropod, it was dwarfed by other close relatives such as Hibbertopterus which could reach lengths exceeding 1. 5 m. The fossil was originally described as a giant spider, but has since been identified as a medium-sized euryopterid. It would have had blade-like structures on its appendages which would have allowed it to engage in a feeding method known as sweep-feeding.
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This page is based on the article Megarachne published in Wikipedia (as of Oct. 31, 2020) and was automatically summarized using artificial intelligence.
