Apteribis
Encyclopedia
Apteribis is an extinct
genus
of flightless bird
s in the ibis
subfamily that was endemic to the Hawaiian Islands
in the Pacific Ocean
.
and Molokai
, which formed part of the prehistoric island of Maui Nui
until about 200,000 years ago when rising sea levels fragmented it. Olson and James
speculate that the genus was endemic to Maui Nui, that the ibises were birds of the forest floor
, that because of their flightlessness they were susceptible to becoming trapped in lava tube
s, and that they may have exerted heavy predation
pressure on Maui Nui’s land snail
s.
Fossil material collected on Maui indicates that a third species apparently occurred there; it was generally larger in size and occurred at lower elevations than A. brevis, and has been referred to as the “Maui Lowland Apteribis”.
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of flightless bird
Flightless bird
Flightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim. They are thought to have evolved from flying ancestors. There are about forty species in existence today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguin...
s in the ibis
Ibis
The ibises are a group of long-legged wading birds in the family Threskiornithidae....
subfamily that was endemic to the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
in the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
.
Distribution
The remains of the small ibises in the genus have only been found on the islands of MauiMaui
The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
and Molokai
Molokai
Molokai or Molokai is an island in the Hawaiian archipelago. It is 38 by 10 miles in size with a land area of , making it the fifth largest of the main Hawaiian Islands and the 27th largest island in the United States. It lies east of Oahu across the 25-mile wide Kaiwi Channel and north of...
, which formed part of the prehistoric island of Maui Nui
Maui Nui
Maui Nui or Greater Maui, is a modern geologists' name given to a prehistoric Hawaiian Island built from seven shield volcanoes. Nui means "great/large" in the Hawaiian language....
until about 200,000 years ago when rising sea levels fragmented it. Olson and James
Helen Frances James
Helen Frances James is an American paleontologist and paleornithologist who has published extensively on the fossil avifauna of the Hawaiian Islands. She is Curator of Birds, in the Department of Vertebrate Zoology, at the National Museum of Natural History in Washington, D.C.Both James’ parents...
speculate that the genus was endemic to Maui Nui, that the ibises were birds of the forest floor
Forest floor
The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...
, that because of their flightlessness they were susceptible to becoming trapped in lava tube
Lava tube
Lava tubes are natural conduits through which lava travels beneath the surface of a lava flow, expelled by a volcano during an eruption. They can be actively draining lava from a source, or can be extinct, meaning the lava flow has ceased and the rock has cooled and left a long, cave-like...
s, and that they may have exerted heavy predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
pressure on Maui Nui’s land snail
Land snail
A land snail is any of the many species of snail that live on land, as opposed to those that live in salt water and fresh water. Land snails are terrestrial gastropod mollusks that have shells, It is not always an easy matter to say which species are terrestrial, because some are more or less...
s.
Species
Two species have been described:- A. glenos Olson & Wetmore, 1976 “Molokai Apteribis”
- A. brevis Olson & James, 1991 “Maui Upland Apteribis”
Fossil material collected on Maui indicates that a third species apparently occurred there; it was generally larger in size and occurred at lower elevations than A. brevis, and has been referred to as the “Maui Lowland Apteribis”.