Macrophthalmus

Characteristics

Macrophthalmus crabs exhibit several distinct features:

• Large, prominent eyes: Their eyes are positioned on long, movable stalks, enabling them to detect predators and prey efficiently.
• Broad, flattened carapace: Their carapace is generally broad and flattened, providing them with a low profile and allowing them to burrow effectively.
• Slender, elongated chelipeds: Their chelipeds (claws) are typically slender and elongated, especially in males, and are used for feeding and defense.
• Sexual dimorphism: There are significant differences between the sexes, with males having larger chelipeds and a broader carapace than females.

Environment and Distribution

Macrophthalmus crabs are primarily found in intertidal areas, particularly on sandy or muddy flats. They are also known to inhabit estuaries, mangroves, and seagrass meadows. Their distribution is mainly confined to tropical and subtropical regions, with species found in the Indo-Pacific, Atlantic, and Mediterranean regions.

Behavior

Macrophthalmus crabs are generally active during the day, feeding on algae, detritus, and small invertebrates. They are burrowers, excavating holes in the sediment to shelter from predators and tides. Some species exhibit territorial behavior, defending their burrows against intruders.

Reproduction

Macrophthalmus crabs reproduce sexually. Females release eggs, which are attached to their abdominal appendages (swimmerets) until they hatch. Larvae undergo several molts and developmental stages before metamorphosing into juvenile crabs.

Conservation Status

The conservation status of different Macrophthalmus species varies. Some are considered common and widespread, while others face threats from habitat degradation, pollution, and overfishing.

References

Further information on Macrophthalmus can be found on these websites:

• World Register of Marine Species
• Wikipedia - Macrophthalmidae