Aglaspidida is an extinct order of marine arthropods known from fossils spanning the Middle Cambrian to the Upper Ordovician. Initially considered chelicerates, modern anatomical comparisons demonstrate that the aglaspidids cannot be accommodated within this group, and that they lie instead within the Artiopoda, thus placing them closer to the trilobites, being placed in the artiopod subgroup Vicissicaudata.
Aglaspidida is an extinct order of marine arthropods known from fossils spanning the Middle Cambrian to the Upper Ordovician. Initially considered chelicerates, modern anatomical comparisons demonstrate that the aglaspidids cannot be accommodated within this group, and that they lie instead within the Artiopoda, thus placing them closer to the trilobites, being placed in the artiopod subgroup Vicissicaudata.
With 38 known valid species as of 2017, they represent one of the most diverse groups of early Paleozoic arthropods, after trilobites. Aglaspidid fossils are found in North America (United States and Canada), Europe, Australia, and China.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).