Ancient arthropod kept its brood close

Threads tethered juveniles to parent, fossil suggests

Ancient Arthropod

KEEP CLOSE  The ancient arthropod Aquilonifer spinosus tethered its offspring to its armor, shown in this 3-D rendering.

D. Briggs et al/PNAS 2016

Family ties last 430 million years — at least for one newly discovered arthropod species.

Researchers discovered the fossilized remains of Aquilonifer spinosus encased in carbonate from a formation called the Herefordshire Lagerstätte in England. Shields covered the 9.5-millimeter arthropod from head to tail, and long spines protruded from its armor. But that’s not all: A closer look with 3-D imaging revealed 10 tiny arthropods, ranging in size from 0.5 to 2 millimeters in length, strung to the armor like kites.

A. spinosus represents the first fossil evidence of offspring tethered to a parent, the researchers say. Although no living arthropods use this exact brooding method, some freshwater crustaceans, descendants of this species, exhibit similar protective strategies, the team reports online April 4 in the Proceedings of the National Academy of Sciences.

The spiny creature’s name, Aquilonifer, reflects its unique parenting style. Aquilone is Italian for toy kite, and the suffix –ifer means “to carry”.

Cassie Martin is a deputy managing editor. She has a bachelor's degree in molecular genetics from Michigan State University and a master's degree in science journalism from Boston University.

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