麻豆淫院

The Polish Geological Institute-National Research Institute reports a Lower Devonian (419 to 393 million years ago) fossilized trackway in the Holy Cross Mountains, Poland, attributed to dipnoan fish. Their analysis finds what appears to be the earliest record of fish testing the land mobility skills of vertebrates, predating by about 10 million years the first evidence of fully terrestrial tetrapod locomotion.

Preadaptation to the invasion on land is a requirement for later, more permanent stays, likely motivated by gaining access to new feeding areas during low tide. Few sites have recorded locomotion traces from the first vertebrates to colonize land, mainly from Europe and one from Australia, with the previous oldest to date coming from the lower Middle Devonian of the Holy Cross Mountains, Poland.

Numerous terrestrial locomotory traces of a similar age occur on Valentia Island, Ireland. Evidence indicates tetrapods were already capable of efficient locomotion on land at the beginning of the Middle Devonian, suggesting that the origins of quadrupedalism should be sought in even older formations.

In the study, "Traces of dipnoan fish document the earliest adaptations of vertebrates to move on land," in Scientific Reports, researchers analyzed newly excavated trace fossils and 3D scans to interpret the locomotion and snout anchoring attributed to dipnoan fishes.

Field teams worked two sections in small, abandoned sandstone quarries at Ujazd and Kopiec near Iwaniska in the central Holy Cross Mountains, about 190 km south of Warsaw, within Lower Devonian (middle-upper Emsian) siliciclastic marginal marine deposits. Here, sandstones formed in a marginal marine environment showing numerous manifestations of emersion and settlement by terrestrial vegetation.

Tuffite cover protected the trace-bearing surfaces from bioturbation, yielding "true substrate" bedding planes that record the sediment鈥搘ater or sediment鈥揳ir interface and a period of stasis before subsequent deposition. A surface area of about 30 m² at Ujazd and about 15 m² at Kopiec preserves several dozen documented trace fossils in situ.

Methods included excavation of partially exposed sandstone bed surfaces, cleaning and washing, field photography, 3D scanning, silicone rubber casting, and in situ protection. Measurements and scans used a 3D scanner eviXscan Loupe+ and were analyzed with BLENDER 2.6. 3D scans were also made using a hand-held scanner ZScannerTM 800 h with XYZ resolution 50 mm.

Characteristic features of the snout imprints include a trapezoidal outline in dorsal view, a deep curved profile of the lower jaw in lateral view, and a pair of arches in the ventral margin of the upper lip that match short-snouted Devonian lungfishes such as Dipnorhynchus or "Chirodipterus" australis.

Interpretation excludes swimming because the sinusoidal pattern characteristic of Undichna is absent. Observations document almost 11% twisted traces, of which 97% are twisted to the left. A merged dataset of 35 left-turning traces appears to be statistically significant and may represent the earliest presumed instance of handedness among vertebrates, with a possible left-handed preference.

Researchers conclude that one of the trackways was produced by a partly emerged dipnoan fish, including traces of the trunk, fins, and snout anchoring in the sediment for body leverage, with fins used as auxiliary tools to adjust movement. In another, single or double pairs of furrows record a fish resting on its fins in the sediment.

Evidence represents the oldest known vertebrate locomotion in a semi-terrestrial environment and reveals anatomically shared or convergent capabilities of a sister group independent of the true tetrapod lineage.

漏 2025 Science X Network