New study indicates that Cretaceous fossil identified 70 a long time ago…
A fossil slab identified in Kansas 70 years ago and twice misidentified — to start with as a eco-friendly alga and then as a cephalopod — has been reinterpreted as the preserved remains of a big cartilaginous fish, the group that contains sharks and rays. In a research published in the Journal of Paleontology, American Museum of Pure Background researchers describe the fishy features of the animal, which lived among 70-85 million many years ago.
“There are lots of illustrations of briefly misplaced taxa in paleontological history, including ferns that were being the moment thought to be sponges and lungfish teeth assumed to be fungi,” claimed the guide author, Allison Bronson, a comparative biology Ph.D.-diploma university student in the Museum’s Richard Gilder Graduate College. “In this case, the misidentification did not materialize mainly because of a absence of technological know-how at the time — scientists familiar with cartilage construction could easily see this was a chondrichthyan fish. The scientists utilised acceptable arguments for their interpretations, but failed to glance outdoors of their very own fields.”
The enigmatic specimen, Platylithophycus cretaceum, is roughly 1.5-feet long by 10-inches huge and from the Niobrara Development in Kansas. The Niobrara Formation is 1 of the most varied fish-fossil web-sites in North The united states, preserving late Cretaceous animals that lived in and close to the Western Interior Seaway, a wide expanse of drinking water that break up North The united states into two land masses.
In 1948, two paleobotanists from the Colorado Faculty of Mines and Princeton College as opposed the texture of the fossil slab with that of inexperienced algae. They explained two areas of a plant: surfaces covered with hexagonal plates, which they referred to as “fronds,” and supposedly calcium carbonate-included thread-like filaments. In 1968, two scientists from Fort Hays Kansas State Higher education learning cephalopods from the Niobrara Development when compared the specimen with a cuttlefish, based largely on its textural similarities to a cuttlebone — the distinctive inside shell of cuttlefish. The reclassification built Platylithophycus the oldest sepiid squid then on file.
In the two of these earlier scientific studies, the hard tissue was assumed to be composed of calcium carbonate, but no exams were being performed. For the new review, Bronson and co-writer John Maisey, a curator in the Museum’s Division of Paleontology, utilized a small sum of dilute natural and organic acid to the specimen — a approach that has been commonly utilized in paleontology considering the fact that the time of the preliminary description of Platylithophycus. If there is a response, the fossilized content is probably made from calcium carbonate. But if there is no reaction, which was the situation when Bronson and Maisey done the test, it is very likely built from calcium phosphate, as are the fossilized skeletons of cartilaginous fish like sharks and rays.
The most noticeable clue that Platylithophycus was a cartilaginous fish are the hexagonal plates on the area of the specimen. Just after taking a closer search with a scanning electron microscope, Bronson and Maisey reinterpreted that attribute as tessellated calcified cartilage, identified on the two extinct and dwelling sharks and rays. The new analyze suggests that the “filaments” before described are truly part of the gill arches, produced up of tessellated cartilage. Gill arches are cartilaginous curved bars along the pharynx, or throat, that guidance the gills of fish. The “fronds” are reinterpreted as gill rakers, finger-like projections that extend from the gill arches and help with feeding.
“We feel this was a somewhat massive cartilaginous fish, maybe linked to living filter-feeding rays these kinds of as Manta and Mobula,” Maisey explained. “This possibly expands the assortment of variety in the Niobrara fauna.”
But due to the fact this fossil only preserves the animal’s gills and no added pinpointing capabilities like enamel, it simply cannot be supplied a new name or reunited with an existing species. So till then, this fish will still carry the title of a plant.
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