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Cephalopods, as active marine predators, possess sensory organs specialized for use in aquatic conditions. [1] They have a camera-type eye which consists of an iris, a circular lens, vitreous cavity (eye gel), pigment cells, and photoreceptor cells that translate light from the light-sensitive retina into nerve signals which travel along the optic nerve to the brain. [2]
However, most of other researchers do not agree that Nectocaris actually being a cephalopod or even mollusk. [140] [141] Early cephalopods were likely predators near the top of the food chain. [25] After the late Cambrian extinction led to the disappearance of many radiodonts, predatory niches became available for other animals. [142]
Cuttlefish, like other cephalopods, have sophisticated eyes. The organogenesis and the final structure of the cephalopod eye fundamentally differ from those of vertebrates, such as humans. [20] Superficial similarities between cephalopod and vertebrate eyes are thought to be examples of convergent evolution. The cuttlefish pupil is a smoothly ...
In a broad sense, "nautiloid" refers to a major cephalopod subclass or collection of subclasses (Nautiloidea sensu lato). Nautiloids are typically considered one of three main groups of cephalopods, along with the extinct ammonoids (ammonites) and living coleoids (such as squid, octopus, and kin).
Many species of molluscs are eaten worldwide, either cooked or raw. Some mollusc species are commercially exploited and shipped as part of the international trade in shellfish; other species are harvested, sold and consumed locally. Some species are collected and eaten locally but are rarely bought and sold.
Nautiluses are much closer to the first cephalopods that appeared about 500 million years ago than the early modern cephalopods that appeared maybe 100 million years later (ammonoids and coleoids). They have a seemingly simple brain, not the large complex brains of octopus, cuttlefish and squid, and had long been assumed to lack intelligence ...
Nautilus is a marine cephalopod genus in the mollusk family Nautilidae. Species in this genus differ significantly, morphologically, from the two nautilus species in the adjacent sister-taxon Allonautilus. [2]
Scallops have up to 100 simple eyes. The molluscs have the widest variety of eye morphologies of any phylum, [1] and a large degree of variation in their function. Cephalopods such as octopus, squid, and cuttlefish have eyes as complex as those of vertebrates, while scallops have up to 100 simple eyes.