#crustacea

Petrolisthes violaceus, a species of porcelain crab, in Los Molles, Chile

📍 Location: Nags Head, North Carolina

🗓 Date: May 23, 2025

🐾 Media: Image

🌿 Species: Ocellate Lady Crab (Ovalipes ocellatus)

📝 Notes: Fast-moving marine crab found along sandy beaches and shallow coastal waters of the western Atlantic. Recognizable by its pale shell covered in circular “eye-like” spots (ocelli) and long legs adapted for rapid sideways movement and shallow burrowing.

Often encountered in surf zones, tidal flats, or just beneath wet sand. Capable of burying itself quickly when disturbed.

Carapace only.

Lysmata wurdemanni

Blueberry hermit crab

DEEP-SEA DOMINANCE: THE SUPERGIANT AMPHIPOD ACROSS THE ABYSS

The deep-sea amphipod Alicella gigantea, described in 1899, currently known as the world’s largest amphipod, inhabits depths of the lower abyssal and upper hadal zones. Historically, it has been sampled or observed in situ infrequently relative to other deep-sea amphipods, suggesting low population densities and providing a sense of rarity. Consequently, little is known about the demography, genetic variation and population dynamics of A. gigantea.

Although elusive, Alicella gigantea is one of the most widely distributed amphipods known, thriving across more than half of the world’s oceans, according to a recent study by researchers at the University of Western Australia. Amphipods like A. gigantea are shrimp-like crustaceans with narrow bodies and a distinctive hunched posture. They inhabit nearly every aquatic habitat on Earth, from shallow coasts to the hadal trenches, though their numbers dwindle with increasing depth.

In the most comprehensive assessment to date, scientists compiled 195 records from 75 locations across the Pacific, Atlantic, and Indian Oceans, including both published data and new expeditions. Genetic analysis of mitochondrial and nuclear genes revealed extremely low divergence among global populations, supporting the existence of a single, globally distributed species. The haplotype network showed minimal regional differentiation, with shared haplotypes across vast distances and the Pacific identified as the species’ main stronghold. Far from being rare, A. gigantea occupies nearly 60% of the global ocean, a silent giant spanning the deep.

Main photograph: The supergiant amphipods. Oceanlab, University of Aberdeen, UK.