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Oldest Finch-Beaked Birds (1 Viewer)

Fred Ruhe

Well-known member
Netherlands
Daniel T. Ksepka, Lance Grande, Gerald Mayr, 2019

Oldest Finch-Beaked Birds Reveal Parallel Ecological Radiations in the Earliest Evolution of Passerines

Current Biology 29, 1–7

Highlights

- Finch-beaked bird fossils provide evidence for Eocene passerines with seed-based diets

- Eocene stem passerines underwent a radiation paralleling that of modern passerines

- Stem passerines evolved a wide array of beak shapes but ultimately died out

In Brief
Ksepka et al. report two new fossil bird species which are the oldest birds with a finch-like beak. Phylogenetic analyses reveal that these birds are part of a diverse radiation of early stem passerines (perching birds).

SUMMARY

Beak shape plays a key role in avian radiations and is one of the most intensely studied aspects of avian evolution and ecology [1–4]. Perhaps no other group is more closely associated with the study of beak shape than Passeriformes (passerines or perching birds), the most species-rich ordinal clade of modern birds. However, despite their extraordinary present-day diversity, our understanding of early passerine evolution has been hindered by their sparse fossil record [5, 6]. Here, we describe two new species of early Eocene stem passerines from the Green River Formation of the United States and the Messel Formation of Germany. These species are the oldest fossil birds to exhibit a finch-like beak and provide the earliest evidence for a diet focused on small, hard seeds in crown birds. Given that granivory is a key adaptation that allows passerines to exploit open temperate environments, it is notable that both species occurred in subtropical environments [7, 8]. Phylogenetic analyses place both species within the Psittacopedidae, an extinct Eocene clade of zygodactyl stem passeriforms that also includes the slender-beaked nectarivorous Pumiliornis, the short-beaked Psittacopes, and the thrush-beaked Morsoravis. Our results reveal that stem passerines attained a diversity of beak shapes paralleling many of the morphotypes present in extant passerine finches, thrushes, and sunbirds, more than 35 million years before these morphotypes arose in the crown group. Extinction of these ecologically diverse fossil taxa may be linked to more sophisticated nest construction in anisodactyl crown passerines versus cavity-nesting in Eocene zygodactyl stem passerines [9].

The paper describes:

Eofringillirostrum Ksepka, Mayr, and Grande gen. nov.
Eofringillirostrum boudreauxi sp. nov. (type species).
Eofringillirostrum parvulum sp. nov.

Free pdf: https://www.cell.com/current-biology/pdf/S0960-9822(18)31674-9.pdf

More information will follow.

Enjoy,

Fred
 

Fred Ruhe

Well-known member
Netherlands
Systematic Paleontology

Systematic Paleontology

Aves Linnaeus, 1758.
Pan-Passeriformes Linnaeus, 1758.
Psittacopedidae Mayr, 2015.
Eofringillirostrum Ksepka, Mayr, and Grande gen. nov.

Type Species
Eofringillirostrum boudreauxi sp. nov.

Included Species
Eofringillirostrum boudreauxi and Eofringillirostrum parvulum.

Etymology
From Greek eos (‘‘dawn’’), Latin fringilla (‘‘finch’’), and Latin rostrum (‘‘beak’’).

Eofringillirostrum boudreauxi Ksepka, Grande, and Mayr sp. nov.

Holotype
FMNH PA 793, articulated skeleton with feather remains

Etymology
Named after Terry Boudreaux, who donated the holotype to the Field Museum.

Type Locality and Horizon

Locality A [7], ‘‘Sandwich beds’’ of the early Eocene Fossil Butte Member of the Green River Formation at Lewis Ranch, near Kemmerer, Wyoming, USA.

Eofringillirostrum parvulum Mayr, Ksepka, and Grande sp. nov.

Holotype

IRSNB Av 128a+b, partial skeleton on two slabs

Etymology

From Latin parvulum (‘‘small’’).

Type Locality and Horizon

Early Eocene Messel Formation near Darmstadt, Germany

Fred

Attached: Holotypes of Eofringillirostrum boudreauxi (a, b, c, d, e) and Eofringillirostrum parvulum (f, g, h, i) and phylogenetic relationships of early passerines.
 

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