Late Pleistocene songbirds of Liang Bua (Flores, Indonesia); the first fossil passerine fauna described from Wallacea.

Hanneke J.M Meijer,Sri Wasisto,Matthew W Tocheri,Wahyu Saptomo,Gerald Mayr,Rokus Awe Due,Thomas Sutikna,Jatmiko Jatmiko

doi:10.7717/peerj.3676

Abstract

BackgroundPasserines (Aves: Passeriformes) dominate modern terrestrial bird communities yet their fossil record is limited. Liang Bua is a large cave on the Indonesian island of Flores that preserves Late Pleistocene–Holocene deposits (∼190 ka to present day). Birds are the most diverse faunal group at Liang Bua and are present throughout the stratigraphic sequence.MethodsWe examined avian remains from the Late Pleistocene deposits of Sector XII, a 2 × 2 m area excavated to about 8.5 m depth. Although postcranial passerine remains are typically challenging to identify, we found several humeral characters particularly useful in discriminating between groups, and identified 89 skeletal elements of passerines.ResultsAt least eight species from eight families are represented, including the Large-billed Crow (Corvus cf. macrorhynchos), the Australasian Bushlark (Mirafra javanica), a friarbird (Philemon sp.), and the Pechora Pipit (Anthus cf. gustavi).DiscussionThese remains constitute the first sample of fossil passerines described in Wallacea. Two of the taxa no longer occur on Flores today; a large sturnid (cf. Acridotheres) and a grassbird (Megalurus sp.). Palaeoecologically, the songbird assemblage suggests open grassland and tall forests, which is consistent with conditions inferred from the non-passerine fauna at the site. Corvus cf. macrorhynchos, found in the Homo floresiensis-bearing layers, was likely part of a scavenging guild that fed on carcasses of Stegodon florensis insularis alongside vultures (Trigonoceps sp.), giant storks (Leptoptilos robustus), komodo dragons (Varanus komodoensis), and probably H. floresiensis as well.

Highlights

Passerines (Aves: Passeriformes), which include the globally distributed songbirds (Oscines), constitute nearly 60% of extant bird species and occupy almost every terrestrial habitat (Sibley & Monroe, 1990; Jetz et al, 2012)
In order to better understand the avifauna and palaeoecology of Liang Bua, as well as the biogeography of Wallacean bird communities, we aimed to identify passerine remains from the Late Pleistocene sediments at Liang Bua, which would constitute the first fossil assemblage of songbirds described from Wallacea
The songbirds identified from the Late Pleistocene sediments at Liang Bua (Fig. 5, Table 2) constitute the first fossil passerine sample described from Wallacea

Summary

Introduction

Passerines (Aves: Passeriformes), which include the globally distributed songbirds (Oscines), constitute nearly 60% of extant bird species and occupy almost every terrestrial habitat (Sibley & Monroe, 1990; Jetz et al, 2012). The avifauna includes at least 90 species of passerines (Table 1; Verhoeye & Holmes, 1998; Mees, 2006; Eaton et al, 2016), of which three are endemic to the island; the Flores crow Corvus florensis, the Flores Monarch Symposiachrus sacerdotum, and the Flores Warbling-flycatcher Eumyias oscillans. Passerines (Aves: Passeriformes) dominate modern terrestrial bird communities yet their fossil record is limited. Liang Bua is a large cave on the Indonesian island of Flores that preserves Late Pleistocene–Holocene deposits (∼190 ka to present day). These remains constitute the first sample of fossil passerines described in Wallacea. Corvus cf. macrorhynchos, found in the Homo floresiensis-bearing layers, was likely part of a scavenging guild that fed on carcasses of Stegodon florensis insularis alongside vultures (Trigonoceps sp.), giant storks (Leptoptilos robustus), komodo dragons (Varanus komodoensis), and probably H. floresiensis as well

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