Macrophthalmidae
The Macrophthalmidae, commonly known as the “sand-bubbler crabs”, are a family of crabs in the infraorder Brachyura. These crabs are found in coastal areas of the Indo-Pacific region, the Atlantic Ocean, and the Mediterranean Sea. Macrophthalmidae are known for their distinctive large, protruding eyes, which give them their common name.
Characteristics
Macrophthalmidae are generally small to medium-sized crabs, with a carapace width ranging from a few millimeters to several centimeters. They have a distinct, flattened carapace with a pair of prominent, stalked eyes that are significantly larger than the other appendages. Their body shape is adapted for burrowing, with strong claws and a narrow, pointed abdomen. These crabs exhibit sexual dimorphism, with males typically having larger claws and a wider carapace than females.
Some species, such as the "sand-bubbler crab" (Macrophthalmus dilatatus), are known for their unique behavior of creating "sand-bubbler" mounds. They use their claws to excavate sand and create small mounds, which are then used to filter food from the water.
Environments
Macrophthalmidae are primarily found in intertidal and subtidal zones of sandy and muddy shores. They are often found in estuaries, lagoons, and coastal areas with high salinity levels. These crabs are generally active during low tide, foraging for food and burrowing into the sediment to avoid predators.