How does a sand flea look? - briefly
A sand flea is a tiny, laterally compressed crustacean about 2–5 mm long, featuring a translucent gray‑brown exoskeleton, long segmented antennae, and enlarged hind legs designed for rapid jumping. Its body consists of a head, thorax, and abdomen covered with small overlapping plates, giving it a smooth, streamlined appearance.
How does a sand flea look? - in detail
Sand fleas, members of the family Talitridae, are small crustaceans adapted to life on sandy beaches. Adult individuals typically measure 5–12 mm in length, with a laterally compressed body that tapers toward the rear. The exoskeleton displays a smooth, glossy surface, often pale beige or light brown, which blends with the surrounding sand and reduces visual detection by predators.
The head bears two short, stalked compound eyes positioned near the front, providing a wide field of vision. Antennae consist of two segments: a longer, sensory flagellum and a shorter basal peduncle, both covered in fine setae that detect chemical cues and vibrations. Mandibles are robust, allowing the animal to scrape detritus and algae from the substrate.
The thorax comprises three segments, each bearing a pair of pereopods (walking legs). The first two pairs are adapted for rapid digging, equipped with flattened, spade‑like dactyls that displace sand efficiently. The third pair is longer and more slender, used for swimming and occasional jumping. Legs end in small claws that grip particles and aid in locomotion across loose sand.
Abdomen consists of six fused segments forming a compact tail fan. The uropods at the posterior end are flattened and fringed with setae, functioning as a rudder during swimming bursts. The telson, a small terminal plate, completes the body outline.
Sexual dimorphism appears in the form of enlarged pleopods in males, which serve as clasping structures during copulation. Females possess a brood pouch (marsupium) formed by oostegites, where developing embryos are protected until release as miniature juveniles.
Coloration may vary slightly with species and environmental conditions, ranging from translucent gray to mottled tan. Pigmentation is generally uniform, lacking distinct markings, which enhances camouflage against the pale beach surface.
Key morphological traits—compact size, flattened body, specialized digging legs, and a tail fan—enable sand fleas to burrow quickly, avoid wave action, and exploit intertidal zones where organic debris accumulates.