Eurylaimides: The Diverse Clade of Old World Suboscines
The Eurylaimides represent a fascinating clade of passerine birds—perching birds characterized by their specific foot and toe arrangements. Known as the Old World suboscines, these birds are primarily distributed across the tropical regions surrounding the Indian Ocean. While their presence is strongest in these areas, the group also includes a specialized inland African species, Grauer's broadbill, and a single representative in the Americas, the sapayoa.
The classification of these birds has evolved as scientific understanding of their genetic relationships has deepened, leading to a structured hierarchy of superfamilies and families recognized by the International Ornithologists' Union (IOC).
Key Facts
- Distribution: Mainly tropical regions around the Indian Ocean, with outliers in inland Africa and the Americas.
- Taxonomy: Divided into three superfamilies and five distinct families.
- Key Groups: Includes broadbills, pittas, asities, and the sapayoa.
- Scientific Basis: Modern phylogenetic relationships are based on research such as Oliveros et al. (2019).
Taxonomic Structure and Classification
The Eurylaimides clade is organized into three superfamilies, each containing specific families of birds. This structure helps ornithologists categorize the birds based on their evolutionary lineage.
Sapayooidea
This superfamily is monotypic, meaning it contains only one family: Sapayoidae. This family consists of a single species known as the broad-billed sapayoa, which is the only member of this clade found in the Americas.
Eurylaimoidea
This group encompasses the broadbills, split into two families:
- Eurylaimidae: The typical broadbills.
- Calyptomenidae: The African and green broadbills.
Pittoidea
The Pittoidea superfamily includes two distinct families of colorful tropical birds:
- Pittidae: The pittas.
- Philepittidae: The asities.
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Evolution of Historical Classification
The way scientists categorize the Eurylaimides has shifted over time. Previously, the clade was divided into only two superfamilies: Eurylaimoidea and Pittoidea. In the older system, the asities (Philepittidae) and the sapayoa (Sapayoidae) were both grouped under Eurylaimoidea.
Recent phylogenetic research, notably the 2019 study by Oliveros et al., led to significant changes. The sapayoa was moved into its own dedicated superfamily, Sapayooidea. Simultaneously, the asities (Philepittidae) were relocated to the superfamily Pittoidea to be grouped with the pittas (Pittidae).
| Superfamily | Family | Common Name/Group |
|---|---|---|
| Sapayooidea | Sapayoidae | Broad-billed sapayoa |
| Eurylaimoidea | Eurylaimidae | Typical broadbills |
| Eurylaimoidea | Calyptomenidae | African and green broadbills |
| Pittoidea | Pittidae | Pittas |
| Pittoidea | Philepittidae | Asities |
Frequently Asked Questions
What are Eurylaimides?
Eurylaimides are a clade of passerine birds known as Old World suboscines, found mostly in tropical regions around the Indian Ocean, as well as in Africa and the Americas.
Which species of Eurylaimides is found in the Americas?
The sapayoa (family Sapayoidae) is the only species within this clade located in the Americas.
How many families are recognized in the Eurylaimides clade?
There are five recognized families: Sapayoidae, Eurylaimidae, Calyptomenidae, Pittidae, and Philepittidae.
What changed in the recent classification of asities?
The asities (Philepittidae) were moved from the superfamily Eurylaimoidea to the superfamily Pittoidea, where they are now grouped with the pittas.
Which superfamily is considered monotypic?
Sapayooidea is monotypic because it contains only one family, the Sapayoidae.