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Laridae

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Laridae is a diverse family of seabirds within the order Charadriiformes. This group includes several well-known types of birds, such as gulls, terns, noddies, and skimmers. Currently, the family contains 105 different species organized into 23 distinct genera. These birds are highly adaptable and can be found in almost every part of the world. Most members of this family are aerial birds, meaning they spend a large portion of their lives flying. This ability to fly and adapt has allowed them to spread across many different environments.

Ahlainen.vaakuna
Ahlainen.vaakuna

Scientists use taxonomy to classify and group these birds based on their relationships. The family name Laridae was introduced in 1815 by Constantine Samuel Rafinesque. Historically, the classification was much more fragmented. Gulls were kept in their own group, while terns were placed in a family called Sternidae. Skimmers were categorized in a third family named Rynchopidae. In 1990, researchers Charles Sibley and Jon Ahlquist expanded the family to include auks and skuas. Later, a 2007 molecular phylogenetic study by Baker and colleagues changed things again. They discovered that noddies in the genus Anous were a sister group to gulls, skimmers, and terns. To ensure the family was monophyletic, or consisting of all descendants from a common ancestor, the families Sternidae and Rynchopidae were merged into Laridae.

The family is divided into several subfamilies that represent different lineages. The subfamily Larinae includes the gulls, which contains the large genus Larus with 25 species. The subfamily Rynchopinae consists of skimmers, represented by the genus Rynchops which has only 3 species. The subfamily Gyginae contains the white terns, such as the genus Gygis. The subfamily Anoinae includes the noddies, specifically the genus Anous which has 5 species. Finally, the subfamily Sterninae includes various terns. This subfamily is quite large and contains many genera, such as Sterna, which has 13 species, and Thalasseus, which has 7 species.

Ahlainen.vaakuna
Ahlainen.vaakuna

Understanding the evolutionary history of Laridae requires looking back millions of years. Baker and colleagues found that the Laridae lineage diverged from the ancestors of skuas and auks before the end of the Cretaceous period. This was the age of the dinosaurs. They also suggested that Laridae began to expand during the early Paleocene, roughly 60 million years ago. However, this timeline is a subject of scientific debate. The German paleontologist Gerald Mayr has questioned these early dates. He suggested that inappropriate fossils might have been used to calibrate the molecular data. The earliest known fossils of birds in the order Charadriiformes date to the late Eocene, about 35 million years ago.

Biological traits also help scientists distinguish between these different groups. Researchers Anders Ödeen and his colleagues studied how some shorebirds developed ultraviolet vision. They looked for a specific gene called the SWS1 opsin gene. Their research showed that this gene is present in the lineages of gulls, skimmers, and noddies. Interestingly, the tern lineage does not possess this specific trait. This discovery provides a way to see how different evolutionary paths led to different sensory abilities. The study also suggested that noddies might be an early lineage, though the evidence for this was not considered strong.

Ahlainen.vaakuna
Ahlainen.vaakuna

The distribution and habitat of Laridae species are incredibly widespread. While their ancestors may have been "beachcombing" birds that walked on shores, most modern species are much more aerial. Gull diversity is highest in the northern hemisphere at temperate latitudes. However, there are many exceptions to this pattern. The Ivory Gull lives in the High Arctic, while the kelp gull can be found as far south as Antarctica. Terns and skimmers generally prefer warmer temperate, subtropical, and tropical regions. A notable exception is the Arctic tern, which extends its range to polar latitudes in both hemispheres.

Many species change their behavior based on the time of year. During the breeding season, these birds typically nest in coastal regions or marshlands. When the nonbreeding season arrives, many species fly far offshore. In these periods, they often become pelagic, meaning they live in the open ocean. This movement between coasts and the open sea is a key part of their life cycle. Their ability to thrive in both coastal and deep-sea environments highlights the incredible adaptability of the Laridae family.

Ahlainen.vaakuna
Ahlainen.vaakuna
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