For every paper published in Functional Ecology, the authors write a plain language or lay summary, which explains the research (and its importance) in a generally accessible way
Isabelle Kruta, Yves Cherel, Paul Zaharias, Raphaël Cornette, Vincent Fernandez, Marjorie Roscian, and Isabelle Rouget
There has been evidence of a relationship between diet and jaw shape in numerous taxa, including birds and turtles. In cephalopods (squids, octopuses etc. The jaws are situated in the center of the brachial crown and are referred to as beaks because of their resemblance to parrot beaks. They consist of two chitinous sections, with the radulaa rasp-like structure shared by all molluskspositioned in the center of each. Since cephalopods are primarily nocturnal, active carnivorous predators, it can be challenging to discern their dietary preferences. Because ingestion of hard prey parts is rare and their digestion is rapid, stomach content analyses are also complicated. As a result, beaks could be a useful substitute to learn more about cephalopod diet. However, no one has investigated whether an animal’s shape is related to its ecology, despite the fact that beaks have been used since the 1960s for identification, estimating an animal’s age and size, and even determining where it is in the food chain.
In this paper, we generated approximately 210 3D models of beaks from almost all known families of cephalopods. These models were used to test whether there are differences between species with different ecologies and to quantify their shape in three dimensions. Our findings showed that while closely related species do share similarities, animals from different ecologies actually have different beak shapes. Benthic species, such as octopuses, possess relatively short, round, and powerful beaks, while certain small pelagic squids have more pointed and sharper beaks that are perfect for piercing fish flesh. These findings open up new possibilities for researching the connection between beak function and shape, as well as the potential to forecast the diet of little-known extinct and current species.
For every paper published in Functional Ecology, the authors write a plain language or lay summary, which explains the research and its importance in a generally accessible way
Composition edit The beak of a
Beaks are essentially indigestible and frequently the only recognizable cephalopod remains found in the stomachs of predatory species like sperm whales. They are primarily composed of chitin and cross-linked proteins. [18] Due to a gradient in chemical composition, cephalopod beaks gradually become less stiff as one moves from the tip to the base. The stiffness gradient in the hydrated beaks of Dosidicus gigas, the Humboldt squid, spans two orders of magnitude. [19].
- Side view of the lower beak of Chiroteuthis picteti (3. To properly view this, 3D red-cyan glasses are advised (6 mm LRL, 160 mm ML (estimate))[1].
- A side view of the same specimen’s upper beak (2 7 mm URL)[1] .
Measurements edit Giant squid beak and associated muscles with hand for scale
In teuthology, lower rostral length and upper rostral length are commonly referred to by the acronyms LRL and URL, respectively. These are the typical measurements for Decapodiformes beak size; Octopodiformes prefer hood length. [18] They can be used to calculate the total amount of biomass that the species has consumed, the mantle length, and the original animal’s body weight. [20][21][22][23][24][25][26].
- Lower rostral length
- Upper rostral length
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