Moa-nalo
Encyclopedia
The moa-nalo are a group of extinct aberrant, goose
-like duck
s that lived on the larger Hawaiian Islands
, except Hawaii
itself, in the Pacific. They were the major herbivore
s on most of these islands for the last 3 million years or so, until they became extinct after human settlement.
, having been wiped out before the arrival of Captain
James Cook
(1778), until the early 1980s, when their subfossil
remains were discovered in sand
dune
s on the islands of Molokai
and Kauai
. Subsequently bones were found on Maui
, Oahu
, and Lānai
, in lava tube
s, lake
beds and sinkhole
s. They represent four species
in three genera
so far:
Chelychelynechen, meaning turtle-jawed goose, had a large heavy bill like that of a tortoise
, while the other two genera, Thambetochen and Ptaiochen all had serrations in their bills known as pseudoteeth, similar to those of mergansers. All species were flightless
and large, with a mass of 4–7.5 kg (8.8–16.5 lb).
which were compared to living duck species in order to establish their place in the duck family, Anatidae
(Sorenson et al., 1999). Contrary to the expectations of some scientists, the moa-nalo were not related to the large geese (Anserinae
) but instead the dabbling ducks of the genus Anas
, which includes the mallard
. Indeed, the present DNA analysis' resolution is not high enough to determine their relationships to different species of Anas
, but biogeography
strongly suggests that their closest living relative is the widespread Pacific Black Duck
.
From the DNA sequence
s it has been estimated that the ancestors of the moa-nalo reached the Hawaiian Islands about 3.6 million years ago, by which time the genus Anas was already distributed worldwide. There they increased in size, but must have retained the ability to fly until they had spread to the newer islands. They seem to have lost the power of flight by the time the main island of Hawaii had emerged from the sea (400,000 years ago); there, their niche
was filled by one or two species of now extinct giant Branta
goose presumably related to the surviving Nēnē
.
The unusual shape and size of the moa-nalo can be attributed to their role in the ecology
of prehistoric Hawaii. A study of coprolite
s (fossil dung) of Thambetochen chauliodous found in Puu Naio Cave on lowland Maui has shown they were folivorous
, at least in dry shrub or mesic forest habitat
s eating particularly fronds from fern
s (possibly Asplenium nidus
or Dryopteris wallichiana). This conclusion is backed up by the shapes of their beaks (James & Burney 1997). This indicates they were the principal browsers on the island.
The presence of prominent spines on the leaves and soft young stems of several Hawaiian lobelioids
in the genus Cyanea - unusual in an island flora where such defenses are frequently lost, as in the ākala
(Hawaiian raspberry
) - suggests that the Cyanea evolved these thorn-like prickles on new growth because they protect against browsing by the moa-nalo. The moa-nalo themselves filled the niche
of herbivore usually filled by mammals such as goat
s and deer
, or the giant tortoise
s of Galápagos and other archipelago
es. This has implications for the ecology of Hawaiian Islands today, as a major group of species have been lost.
The moa-nalo went extinct after the arrival of Polynesia
n settlers in the islands, along with many other species; because the flightless birds must have been considered a prime source of meat, probably around 1000 AD or even earlier. Like island taxa from Mauritius
, New Zealand
and Polynesia
, they were unused to mammal
s and were easily taken by hunters or the animals that were introduced and became feral
, such as domestic pig
s.
Goose
The word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....
-like duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
s that lived on the larger 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...
, except Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
itself, in the Pacific. They were the major herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
s on most of these islands for the last 3 million years or so, until they became extinct after human settlement.
Description
The moa-nalo (the name literally means "lost fowl"; an "s" is not added for the plural) were unknown to scienceScience
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
, having been wiped out before the arrival of Captain
Captain (Royal Navy)
Captain is a senior officer rank of the Royal Navy. It ranks above Commander and below Commodore and has a NATO ranking code of OF-5. The rank is equivalent to a Colonel in the British Army or Royal Marines and to a Group Captain in the Royal Air Force. The rank of Group Captain is based on the...
James Cook
James Cook
Captain James Cook, FRS, RN was a British explorer, navigator and cartographer who ultimately rose to the rank of captain in the Royal Navy...
(1778), until the early 1980s, when their subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
remains were discovered in sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
dune
Dune
In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
s on the islands of 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...
and Kauai
Kauai
Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
. Subsequently bones were found on Maui
Maui
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,...
, Oahu
Oahu
Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
, and Lānai
Lanai
Lānai or Lanai is the sixth-largest of the Hawaiian Islands. It is also known as the Pineapple Island because of its past as an island-wide pineapple plantation. The only town is Lānai City, a small settlement....
, 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, lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
beds and sinkhole
Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...
s. They represent four species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in three genera
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...
so far:
- Chelychelynechen quassus from Kauai,
- Ptaiochen pau from Maui,
- Thambetochen xanion from Oahu,
- Thambetochen chauliodous from Maui, Lānai and Molokai (Maui NuiMaui NuiMaui 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....
).
Chelychelynechen, meaning turtle-jawed goose, had a large heavy bill like that of a tortoise
Tortoise
Tortoises are a family of land-dwelling reptiles of the order of turtles . Like their marine cousins, the sea turtles, tortoises are shielded from predators by a shell. The top part of the shell is the carapace, the underside is the plastron, and the two are connected by the bridge. The tortoise...
, while the other two genera, Thambetochen and Ptaiochen all had serrations in their bills known as pseudoteeth, similar to those of mergansers. All species were flightless
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...
and large, with a mass of 4–7.5 kg (8.8–16.5 lb).
Evolution
Some moa-nalo fossils have been found to contain traces of mitochondrial DNAMitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
which were compared to living duck species in order to establish their place in the duck family, Anatidae
Anatidae
Anatidae is the biological family of birds that includes ducks, geese and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica and on most of the world's islands and island groups...
(Sorenson et al., 1999). Contrary to the expectations of some scientists, the moa-nalo were not related to the large geese (Anserinae
Anserinae
The Anserinae is a subfamily in the waterfowl family Anatidae. It includes the swans and true geese. Under alternative systematical concepts , it is split into two subfamilies, the Anserinae containing the geese , while the Cygninae contain the swans.A number of other waterbirds, mainly related to...
) but instead the dabbling ducks of the genus Anas
Anas
Anas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank...
, which includes the mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
. Indeed, the present DNA analysis' resolution is not high enough to determine their relationships to different species of Anas
Anas
Anas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank...
, but biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
strongly suggests that their closest living relative is the widespread Pacific Black Duck
Pacific Black Duck
The Pacific Black Duck is a dabbling duck found in much of Indonesia, New Guinea, Australia, New Zealand, and many islands in the southwestern Pacific, reaching to the Caroline Islands in the north and French Polynesia in the east. It is usually called the Grey Duck in New Zealand...
.
From the DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
s it has been estimated that the ancestors of the moa-nalo reached the Hawaiian Islands about 3.6 million years ago, by which time the genus Anas was already distributed worldwide. There they increased in size, but must have retained the ability to fly until they had spread to the newer islands. They seem to have lost the power of flight by the time the main island of Hawaii had emerged from the sea (400,000 years ago); there, their niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
was filled by one or two species of now extinct giant Branta
Branta
The black geese of the genus Branta are waterfowl belonging to the true geese and swans subfamily Anserinae. They occur in the northern coastal regions of the Palearctic and all over North America, migrating to more southernly coasts in winter, and as resident birds in the Hawaiian Islands...
goose presumably related to the surviving Nēnē
Nene
Nene may refer to:*River Nene, a river in England*Rolls-Royce Nene, a jet engine*Nene , also called Nēnē and Hawaiian Goose, Branta sandvicensis, a rare goose*Nene , a Seminole Indian word meaning "street"...
.
Ecology
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
of prehistoric Hawaii. A study of coprolite
Coprolite
A coprolite is fossilized animal dung. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour rather than morphology. The name is derived from the Greek words κοπρος / kopros meaning 'dung' and λιθος / lithos meaning 'stone'. They...
s (fossil dung) of Thambetochen chauliodous found in Puu Naio Cave on lowland Maui has shown they were folivorous
Folivore
In zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less energy than other types of foods, and often toxic compounds. For this reason folivorous animals tend to have long digestive tracts and slow metabolisms....
, at least in dry shrub or mesic forest habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
s eating particularly fronds from fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s (possibly Asplenium nidus
Asplenium nidus
Asplenium nidus is a species of fern in the family Aspleniaceae, native to tropical southeastern Asia, eastern Australia, Hawaii, Polynesia, Christmas Island, India, and eastern Africa...
or Dryopteris wallichiana). This conclusion is backed up by the shapes of their beaks (James & Burney 1997). This indicates they were the principal browsers on the island.
The presence of prominent spines on the leaves and soft young stems of several Hawaiian lobelioids
Hawaiian lobelioids
The Hawaiian lobelioids are a group of flowering plants in the bellflower family, Campanulaceae, all of which are endemic to the Hawaiian Islands. This is the largest plant radiation in the Hawaiian Islands, and indeed the largest on any island archipelago, with over 125 species...
in the genus Cyanea - unusual in an island flora where such defenses are frequently lost, as in the ākala
Rubus hawaiensis
Rubus hawaiensis, also called the Ākala, is a species of Rubus endemic to Hawaii. It is found on the islands of Kauai, Molokai, Maui, and Hawaii in mesic to wet forest at elevations of...
(Hawaiian raspberry
Rubus
Rubus is a large genus of flowering plants in the rose family, Rosaceae, subfamily Rosoideae. Raspberries, blackberries, and dewberries are common, widely distributed members of the genus. Most of these plants have woody stems with prickles like roses; spines, bristles, and gland-tipped hairs are...
) - suggests that the Cyanea evolved these thorn-like prickles on new growth because they protect against browsing by the moa-nalo. The moa-nalo themselves filled the niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
of herbivore usually filled by mammals such as goat
Goat
The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...
s and deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...
, or the giant tortoise
Giant tortoise
Giant tortoises are characteristic reptiles of certain tropical islands. Often reaching enormous size—they can weigh as much as 300 kg and can grow to be 1.3 m long—they live, or lived , in the Seychelles, the Mascarenes and the Galapagos...
s of Galápagos and other archipelago
Archipelago
An archipelago , sometimes called an island group, is a chain or cluster of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi- and πέλαγος – pélagos through the Italian arcipelago...
es. This has implications for the ecology of Hawaiian Islands today, as a major group of species have been lost.
The moa-nalo went extinct after the arrival of Polynesia
Polynesia
Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including language, culture and beliefs...
n settlers in the islands, along with many other species; because the flightless birds must have been considered a prime source of meat, probably around 1000 AD or even earlier. Like island taxa from Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and Polynesia
Polynesia
Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including language, culture and beliefs...
, they were unused to mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s and were easily taken by hunters or the animals that were introduced and became feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
, such as domestic pig
Domestic pig
The domestic pig is a domesticated animal that traces its ancestry to the wild boar, and is considered a subspecies of the wild boar or a distinct species in its own right. It is likely the wild boar was domesticated as early as 13,000 BC in the Tigris River basin...
s.
See also
- Giant tortoiseGiant tortoiseGiant tortoises are characteristic reptiles of certain tropical islands. Often reaching enormous size—they can weigh as much as 300 kg and can grow to be 1.3 m long—they live, or lived , in the Seychelles, the Mascarenes and the Galapagos...
from several archipelagoes around the world. - Island gigantismIsland gigantismIsland gigantism or insular giantism is a biological phenomenon in which the size of animals isolated on an island increases dramatically in comparison to their mainland relatives....
- Late Quaternary prehistoric birdsLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
- MoaMoaThe moa were eleven species of flightless birds endemic to New Zealand. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about in height with neck outstretched, and weighed about ....
are enormous extinct flightless birds, formerly the largest herbivores in New Zealand.