Exciting new fossil discoveries in a 500-million-year-old Cambrian mudflat in Wisconsin have revealed the earliest evidence of animals venturing onto land, along with insights into their diet. Learn more about Blackberry Hill.
Climactichnites blackberriensis likely stopping to feed on washed-up ostracods.” width=”580″ height=”387″ srcset=”https://cdn.sci.news/images/2026/04/image_14694_1-Climactichnites-blackberriensis.jpg 580w, https://cdn.sci.news/images/2026/04/image_14694_1-Climactichnites-blackberriensis-300×200.jpg 300w, https://cdn.sci.news/images/2026/04/image_14694_1-Climactichnites-blackberriensis-84×55.jpg 84w” sizes=”(max-width: 580px) 100vw, 580px”/>
Mollusc footprints of Climactichnites blackberriensis likely stopping to feed on ostracods. CS = scoopworm crust; DS = decomposing rods; R = ripple mark; S = Ladleworm.
The fossilized remains from Blackberry Hill have revealed that the creatures—a relative of millipedes known as the Eutycarcinoid—created tracks referred to as Protichnites, which means “first footprint.”
Paleontologists have been puzzled over the identity of these creatures for over 150 years.
In these ancient tidal flats, fossilized crustaceans known as Philocariidae have also been identified, alongside thousands of well-preserved trace fossils from various organisms, including arthropods and mollusks.
One of the new trace fossils, Climactichnites blackberriensis, represents a significant imprint likely made by an unidentified mollusk.
These animals traversed the tidal flats, leaving behind a series of footprints. Remarkably, it appears that they stopped to feed on jellyfish that washed ashore.
Cochlichnus? – Traces of polychaete worms believed to be resting.
Fragments of material (crusts) and coccoids are found in the vicinity, potentially indicating some of the earliest fossil evidence of animals feeding on jellyfish in the Cambrian tidal flats.
This may have prompted certain species to explore land, marking the beginning of terrestrial life.
Additional trace fossils feature notable markings, including those from polychaetes, with traces of their parapodia (limbs) documented alongside early occurrences of Stiaria pillosa, believed to be feeding traces of a true carcinoid arthropod.
Stiallia – Presumed feeding traces from ancient arthropods.
Researchers Kenneth C. Gass (Milwaukee Public Museum) and Nora Noffke from Old Dominion University recently released their findings in a paper in the Paleontology Journal. Read the full study here.
The authors also suggested that some of these traces may have been created by certain species of extinct primitive arthropods, such as Aglaspidids, known for their spike-like bifurcated tails.
“These discoveries indicate the Cambrian tidal flats were more active than previously thought. It seems as if all these animals flocked to the flats for a brief reprieve on land,” Gass noted.
“More extensive taxonomic diversity in these tidal flats necessitates further field surveys and material investigations.”
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K. Gass and N. Noffke. 2026. New findings from the Cambrian Moose Mound Complex tidal flat facies, Wisconsin, USA. Paleontology Journal, pp. 1-15; doi: 10.1017/jpa.2026.10225
Source: www.sci.news
