500 million-year-old #fossil is the earliest branch of the #spiders' lineage https://arstechnica.com/science/2024/07/earliest-known-ancestors-of-scorpions-were-tiny-sea-beasts/

Lower #Ordovician synziphosurine reveals early euchelicerate diversity and evolution https://www.nature.com/articles/s41467-024-48013-w

"Some of S. abundantis’ anatomical features allow for a deeper understanding of the early #evolution of #chelicerates and may even link other fossil forms, whose relationships are still highly debated, to this group"

#Discovery of the first ancestors of scorpions, spiders and horseshoe crabs https://phys.org/news/2024-05-discovery-ancestors-scorpions-spiders-horseshoe.html

Lower #Ordovician synziphosurine reveals early euchelicerate diversity and #evolution https://www.nature.com/articles/s41467-024-48013-w

"Measuring between 5 and 10 millimeters in size, it has been named #Setapedites abundantis. This animal makes it possible, for the first time, to trace the entire lineage of #chelicerates, from the appearance of the earliest #arthropods to modern #spiders, #scorpions and #HorseshoeCrabs"

Living species of #DaddyLonglegs has two additional sets of underdeveloped eyes as embryos https://phys.org/news/2024-02-species-daddy-longlegs-additional-underdeveloped.html

#VestigialOrgans alter #fossil placements in an ancient group of terrestrial #chelicerates https://www.cell.com/current-biology/abstract/S0960-9822(24)00153-2

"While a fossilized specimen of a more ancient version of the #arachnid found in 2014 had an additional set of lateral eyes on the side of the head, the new study is the first to show evidence of more than one eye set in a living daddy longlegs species."