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Clupeiformes

life science Maturity 11-13 Next article →

Clupeiformes is a major order of ray-finned fish. This group contains many species that are vital to the world's oceans. They include well-known fish such as herrings, anchovies, and sardines. Because so many larger animals eat them, they are often called forage fish. They play a massive role in the food web of many aquatic ecosystems.

Most fish in this order share specific physical traits. They usually have silvery, streamlined bodies that are shaped like a spindle. This shape helps them move efficiently through the water. Many species also exhibit schooling behavior, where they swim together in large groups. While they typically have eyes, fins, and scales, most Clupeiformes lack a lateral line. A lateral line is a sensory organ used by many other fish to detect movement.

One defining biological feature of these fish is their anatomy. Clupeiformes are classified as physostomes. This means they possess a gas bladder that is connected to the gut by a pneumatic duct. The gas bladder is an internal organ that helps the fish control its buoyancy. They also have a specialized way of eating. Most species are planktivores, meaning they eat plankton. They use structures called gill rakers to filter these tiny organisms from the water as it passes through their gills.

The order is divided into several distinct groups. It contains approximately 405 species organized into ten different families. One suborder is the Denticipitoidei, which includes the Denticipitidae family, known as denticle herrings. Another major suborder is the Clupeoidei. This suborder contains many familiar groups, such as the Clupeidae family, which includes herrings and sprats. Other families include the Engraulidae, which are the anchovies, and the Chirocentridae, known as wolf herrings.

Scientists have traced the complex history of this group through fossils. In the past, many of these fish were part of an order called Isospondyli. Most of those species have since been moved into Clupeiformes. The Clupeiformes had a sister group called the Ellimmichthyiformes. These extinct fish were dominant during the Cretaceous and Paleogene periods. They often lived alongside the early Clupeiformes. While they looked similar at first, some Ellimmichthyiformes evolved very different body plans later in the Cretaceous.

Fossil evidence provides deep insights into when these fish first appeared. In South America, fossils from the Early Cretaceous have been discovered. These fossils appear to be closely related to the Clupeioidei group. This discovery is significant because it suggests a very deep divergence within the Clupeiformes. This means the different branches of this fish group split apart during or even before the Early Cretaceous. This ancient history shows how long these fish have been part of our planet.

The diversity within Clupeiformes is vast and spans many environments. For example, the Ehiravidae family consists of river sprats, showing they can live in fresh water. The Dorosomatidae family includes thread herrings, such as gizzard shads and sardinellas. Other groups like the Alosidae contain shads and sardines. These various families show how the order has adapted to different niches. From the deep ocean to rivers, these fish remain a fundamental part of life in the water.

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