A fishapod fin shows early elbows came in more than one form
New Scientist and ScienceX both describe an Ellesmere Island fin whose bean-shaped elbow hinged in one plane, unlike Tiktaalik's twisting joint. Stewart says the radius pointed where a wrist would sit, offering little push against the ground.
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The isolated fin
New Scientist says the animal is known only from a single isolated fin found on Canada's Ellesmere Island. Thomas Stewart at Pennsylvania State University told the outlet that researchers CT-scanned the fossil and compared its arm-like bones with 16 other described fishapods; the fin matched none of them, which the report reads as evidence of a distinct species. ScienceX carried the same 18 September headline and lede, attributing the specialist story to Christa Lesté-Lasserre's coverage rather than adding new measurements.[1], [2]
A bean-shaped hinge
The New Scientist account describes a long, triangular radius that came to a point where a tetrapod wrist would sit, giving little support for pushing against the ground. At the elbow end the bone was narrow and bean-shaped, so the missing upper-arm joint would have bent mainly in one plane, more restrictively than the twisting elbows seen in Tiktaalik and other fishapods. Stewart is quoted saying the restricted motion may have been an awkward trial of movement that was sufficient rather than optimal. ScienceX repeats that hinge picture without disputing the radius outline.[1], [2]
Variation before limbs
Stewart told New Scientist that researchers keep finding more variation in early fin bones, so the Ellesmere fin adds to a wider menu of elbow geometries rather than a single ladder toward land. The ScienceX repost does not name Journal of Vertebrate Paleontology or list co-authors, so the public pages stop at news-layer anatomy. An alternative read is that an incomplete fin exaggerates how strange the joint looks until more of the animal is found. Both publishers agree the fin is 350 million years old in their ledes.[1], [2]
