Question

What is the name of this creature? It looks like either a crustacean or a conch. Nautilus. Nautilus belauensis.Licenced underCC ASA 3.0 unported, via Wikipedia 2022 from user Manuae. Mollusca -> Cephalopoda (like squid and octopus) -> Nautilaceae -> Nautilidae - comprising of six extant species. They range the 200m to 700m depth of the Indo-Pacific, scavenging carrion. They seem to have been more-or less the same over the last 500 million years according to the fossil record - then being up to 2.5 metres in shell diameter, being more modest now at a maximum of 22 cm (10 inches) when fully grown. They move via jet-propulsion by drawing water in through their hyphonome, then expelling it with force, as seen in the "front view" here: From Profberger at English Wikipedia, freely licensed.

Answer 1

The creature in question is a nautilus, a shelled member of the class Cephalopoda, known for its distinctive spiral shell used for buoyancy control and jet propulsion movement. Nautilus are ancient creatures found in the Indo-Pacific oceans and have remained relatively unchanged over millions of years.

Step-by-step explanation:

The Nautilus

The creature described is a nautilus, which is a member of the class Cephalopoda. Cephalopods are marine animals with prominent heads and sets of tentacles and include species such as squids, octopuses, cuttlefish, and nautilus. The nautilus possesses a distinctive spiral, multi-chambered shell, which is filled with gas or water to regulate buoyancy. It moves via jet propulsion, a characteristic of many cephalopods.

While most modern cephalopods have internal shells or no shell at all, nautilus have retained their ancestral shell, a feature that distinguishes them from other cephalopods like squids, which have a reduced internal shell, and octopuses, which lack a shell altogether. Their shells are made up of interconnected chambers, and a siphuncle runs through these chambers to help them control their buoyancy.

Nautilus are scavengers and have changed very little over hundreds of millions of years according to the fossil record. They are found at depths ranging from 200m to 700m in the Indo-Pacific. Remarkably, the ancient relatives of nautilus had shells up to 2.5 meters in diameter, while the largest modern nautilus reaches only about 22 cm when fully grown.