Introducing a “weird” shark from the Late Cretaceous that, greater than 66 million years in the past, plied the seas feasting upon plankton whereas hovering by means of the water on lengthy, slender fins.
In a brand new research, Romain Vullo and colleagues describe this new species of manta-like planktivorous shark, dubbed Aquilolamna milarcae, from the creatures’ fossilized stays found in northern Mexico. The findings reveal an unexpectedly early evolutionary experimentation with underwater flight amongst sharks predating the rise of comparable traits in manta rays and devilfish by greater than 30 million years.
Elasmobranchs — the extremely profitable group of cartilaginous fishes together with sharks, skates and rays — first appeared in Earth’s oceans roughly 380 million years in the past and have since developed to fill a various array of ecological roles. Fashionable plankton-feeding elasmobranchs are characterised by two distantly associated clades — these with a extra “conventional” shark-like physique form, resembling whale and basking sharks, and people with the smooth, flattened our bodies and winglike fins of Mobulidae rays.
Standing out amongst each dwelling and fossil planktivorous sharks and rays, Aquilolamna milarcae resides someplace in-between. In response to Vullo et al., the newly found extinct species shows many manta-like options, together with unusually lengthy, slender pectoral fins and a large mouth seemingly tailored to filter-feeding. Nevertheless, the winged shark additionally had an elongated, torpedo-like physique and tail, culminating in a definite caudal fin like many different shark species.
The fossils point out that the distinctive elasmobranch was a comparatively sluggish swimmer, utilizing each its lengthy pectoral fins and tail to glide by means of the water whereas scooping up suspended plankton utilizing its massive, gaping mouth. What’s extra, the findings show that winglike fins developed independently in every important lineage of filter-feeding elasmobranchs.
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Reference: “Manta-like planktivorous sharks in Late Cretaceous oceans” by Romain Vullo, Eberhard Frey, Christina Ifrim, Margarito A. González González, Eva S. Stinnesbeck and Wolfgang Stinnesbeck, 18 March 2021, Science.