| Owlet-nightjars Temporal range:Early Miocene to present | |
|---|---|
 | |
| Barred owlet-nightjar (Aegotheles bennettii) | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Clade: | Strisores |
| Clade: | Daedalornithes |
| Order: | Aegotheliformes Worthyet al., 2007 |
| Family: | Aegothelidae Bonaparte, 1853 |
| Genus: | Aegotheles Vigors &Horsfield, 1827 |
| Type species | |
| Caprimulgus novaehollandiae[1] Latham, 1790 | |
| Synonyms | |
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Owlet-nightjars are smallcrepuscular birds related to thenightjars andfrogmouths. Most are native toNew Guinea, but some species extend toAustralia, theMoluccas, andNew Caledonia. Aflightless species fromNew Zealand is extinct. There is a singlemonotypic familyAegothelidae with thegenusAegotheles.
Owlet-nightjars areinsectivores which hunt mostly in the air but sometimes on the ground; their soft plumage is a cryptic mixture of browns and paler shades, they have fairly small, weak feet (but larger and stronger than those of a frogmouth or a nightjar), a tiny bill that opens extraordinarily wide, surrounded by prominent whiskers. The wings are short, with 10 primaries and about 11 secondaries; the tail long and rounded.
A comprehensive 2003 study analyzingmtDNAsequences ofCytochrome b andATPase subunit 8 suggests that 12 living species of owlet-nightjar should be recognized, as well as another that became extinct early in thesecond millennium AD.[2]
The relationship between the owlet-nightjars and the (traditional)Caprimulgiformes has long been controversial and obscure and remains so today: in the 19th century they were regarded as a subfamily of thefrogmouths, and they are still generally considered to be related to the frogmouths and/or thenightjars. It appears though that they are not as closely related to either as previously thought, and that the owlet-nightjars share a more recent common ancestor with theApodiformes.[3] As has been suggested on occasion sincemorphological studies of thecranium in the 1960s,[4] they are thus considered a distinctorder,Aegotheliformes. This, the caprimulgiform lineage(s), and the Apodiformes, are postulated to form aclade calledCypselomorphae, with the owlet-nightjars and the Apodiformes forming the cladeDaedalornithes.
In form and habits, however, they are very similar to both caprimulgiform group – or, at first glance, to smallowls with huge eyes. The ancestors of theswifts andhummingbirds, two groups of birds which are morphologically very specialized, seem to have looked very similar to a small owlet-nightjar, possessing strong legs and a wide gape, while the legs and feet are very reduced in today's swifts and hummingbirds, and the bill is narrow in the latter.
Owlet-nightjars are an exclusively Australasian group, but close relatives apparently thrived all overEurasia in the latePaleogene.
| Phylogeny of the Aegothelidae[2] |
Family Aegothelidae[5]
Afossilproximal righttarsometatarsus (MNZ S42800) was found at theBannockburn Formation of theManuherikia Group near theManuherikia River inOtago,New Zealand. Dating from the Early to MiddleMiocene (Altonian, 19–16million years ago), it seems to represent an owlet-nightjar ancestral toA. novaezealandiae.[6] In 2022, an additional specimen from the same locality wasdescribed by Worthyet al. as a new extinct species ofAeotheles,A. zealandivetus. Theholotype specimen isNMNZ S.52917, a distal right tarsometatarsus.[7]
