Family ACANTHIZIDAE Bonaparte, 1854

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Family ACANTHIZIDAE Bonaparte, 1854

Compiler and date details

December 2014 - N.Wayne Longmore, Museum Victoria

Files of R. Schodde & I.J. Mason, 2001; updated and upgraded by N.W. Longmore, Museum Victoria, 2006

Acanthizinae Bonaparte, C.L. 1854. Notes Ornithologiques sur les Collections Rapportées en 1853, par M.A. Delattre, de son Voyage en Californie et dans le Nicaragua [et Classification Parallélique des Passereaux Chanteurs]. Paris : Mallet-Bachelier Vol. 37.
Type genus:
Acanthiza Vigors & Horsfield, 1827.

Introduction

Acanthizidae is a large polytypic terrestrial and/or arboreal group of small, primarily insectivorous, birds. The basic colour of most is of a sombre nature although several have white or yellow plumage that breaks the uniformity of their appearance. While the centre of diversity is Australia, the family also occurs extensively in New Guinea. A single genus, Gerygone, has spread widely and diversified in New Zealand, south-western Pacific island chains and south-eastern Asia (Schodde & Mason 1999; Dickinson 2003). Australia has some 80% of the known genera. There are some 117 recognised ultrataxa. Several Australian genera are endemic to local areas: Acanthornis to Tasmania, Oreoscopus to northern Queensland, Origma and Pycnoptilus to south-eastern New South Wales.

Thornbills and their allies are ground, trunk or foliage foragers, mostly feeding by gleaning or probing actions. They are gregarious and are communal breeders, constructing domed nests, sometimes with a partly hooded side entrance. Nesting sites are variable: they can be placed in the outer canopies of trees or shrubs, in trunk cavities, on the ground or even in rock shelters or small caves. Most nests are constructed of vegetable matter some are feather lined. Normal egg clutch numbers vary from two to five. Egg colours range from pure white to heavily marked or monochromatic. When marked, the egg colours vary from red-brown to umber; often the colours are in capped or wreathed designs. Many thornbills are accomplished songsters and their vocalisations often include mimicry.

Thornbills are widespread across the continent and Tasmania and a single species occurs on Norfolk and Lord Howe Islands. The family has adapted to occupy all major habitats that occur within their distribution. A number of Australian species are shared with New Guinea; some of these are migratory between the two land masses. Within Australia, most species are either sedentary or locally nomadic. Six species are shared with New Guinea (five Gerygone and one Sericornis), and one Gerygone is shared with New Zealand, though in each instance the ultrataxa differ.

The arrangement of subfamilies, tribes and genera presented here is based on several recent phylogenetic studies, primarily using molecular methods, including Gardner et al. (2010), Marki et al. (2017) and Norman et al. (2018) .

Diagnosis

'Acanthizids have twin shallow furrows at the head of the humerus, on either side of the decurrent ventral tubercle, in the place of the pneumatic fossae found in other groups of song-birds (also Olson 1987). Yet they differ from their sister families in several significant structural features. In the palate, in particular, club-shaped maxillo-palatines of varying ossification overlie a truncated, flat and almost tongue-shaped vomer. Where linguiform, the tip appears to have been produced by evagination of the apex, leaving vestiges of the vomerine horns as nipples at the sides; only Acanthornis retains extended remnants of the horns.'