The ocean teems with life, often challenging our perceptions of size. While many envision shrimp as small, unassuming creatures, some can reach remarkable dimensions. This article explores the distinctions defining these crustaceans and uncovers the true giants among them.
What Defines a True Shrimp?
The term “shrimp” is often used broadly, but scientifically, a “true shrimp” belongs to the infraorder Caridea within the order Decapoda. True shrimp possess distinct anatomical features, such as plate-like gills, unlike the branching gills found in prawns.
Another distinction lies in their body structure and reproductive habits. True shrimp have a body that can curl significantly, with overlapping abdominal segments. Female true shrimp brood their fertilized eggs on the underside of their bodies until they hatch, unlike prawns which release eggs directly into the water.
The World’s Longest True Shrimp
Among true shrimp, the Banded Coral Shrimp (Stenopus hispidus) is recognized for its considerable length, primarily due to elongated appendages. While its body length reaches up to 10 centimeters (4 inches), its prominent white antennae and oversized third pair of legs contribute significantly to its overall span, extending to about 12.7 centimeters (5 inches).
Identifying the “longest” true shrimp is complex, as measurements can refer to body length or total length including antennae. The Banded Coral Shrimp, a caridean, is notable for its total length rather than just body size. Other deep-sea caridean species also exceed 10 centimeters, indicating size diversity within this infraorder.
Habitat and Characteristics of the Longest True Shrimp
The Banded Coral Shrimp (Stenopus hispidus) thrives in tropical marine environments globally, inhabiting coral reefs, rocky ledges, and crevices. Its distribution is extensive, ranging from the Indo-Pacific to the Western Atlantic. These shrimp are often observed hanging upside down beneath ledges.
This species is recognized for its distinctive red and white banded body, giving it a barber pole-like appearance. They are primarily nocturnal cleaner shrimp, feeding on parasites and dead tissue from fish, as well as scavenging on detritus. Banded Coral Shrimp form monogamous pairs, often sharing a burrow or reef area.
Other Large Crustacean Look-Alikes
Many large crustaceans are colloquially referred to as “shrimp” but are not true shrimp, belonging to different infraorders or orders. One prominent example is the Giant Freshwater Prawn (Macrobrachium rosenbergii), a dendrobranchiate. This species can reach impressive sizes, with males growing up to 33 centimeters (13 inches) in total length. Giant Freshwater Prawns are distinguished by their long, slender second pair of legs, which are often blue or orange, and their bodies tend to be straighter compared to true shrimp.
Another large crustacean frequently mistaken for a shrimp is the mantis shrimp, which belongs to the order Stomatopoda, distinct from both true shrimp and prawns. While many mantis shrimp species average around 10 centimeters (4 inches) in length, some, like the Zebra Mantis Shrimp, can grow much larger, reaching up to 38 to 46 centimeters (15 to 18 inches). Mantis shrimp are known for their powerful, club-like or spear-like raptorial claws, which they use for hunting, and their uniquely complex visual systems.