Moa-nalo

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Note: There is an unrelated extinct bird from New Zealand named the Moa.

iMoa-nalo
Artist's conception of the high-billed Chelychelynechen quassus. The color pattern is adapted from the Pacific Black Duck, quite likely their closest living relative.
Conservation status
Prehistoric </div>
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Anseriformes Family: Anatidae
Genera
Chelychelynechen Thambetochen Ptaiochen

The Moa-nalo are a group of extinct aberrant ducks that formerly lived on the Hawaiian Islands in the Pacific. They were the major herbivores on the islands for the last 3 million years until they became extinct when humans first reached the islands.

[edit] Description

The Moa-nalo (the name literally means "lost fowl") were unknown to science, having been wiped out before the arrival of Captain Cook (1778), until the early 1980s, when their sub-fossil remains were discovered in sand dunes on the islands of Molokaʻi and Kauaʻi. Subsequently fossils were found on Maui, Oʻahu and Lānaʻi, the remains found in lava tubes, in lakebeds and sinkholes. They represent four species in three genera so far:

• Chelychelynechen quassus (from Kauaʻi),
• Ptaiochen pau (from Maui),
• Thambetochen xanion (from Oʻahu) and
• Thambetochen chaulious, (from Maui, Lānaʻi and Molokaʻi: Maui Nui)

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. All the species were large, weighing between 4 to 7.5 kg, and were flightless.

[edit] Evolution and Ecology

Some of the fossils found contained traces of mtDNA, which were compared to living duck species in order to establish their place in the duck family, Anatidae (Sorenson et al., 1999). Contrary to expectations, the Moa-nalos were not related to the large geese (Anserinae) but instead the dabbling ducks of the genus Anas (for example the Mallard); indeed, the present DNA analysis's 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 sequences it has been estimated that the moa-nalos' ancestors 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 Hawaiʻi had emerged from the sea, instead their niche was filled by a giant Branta goose related to the Nēnē.

The unusual shape and size of the Moa-nalo can be attributed to their role in the ecology of prehistoric Hawaiʻi. Studies of coprolites (fossil dung) found in caves associated with their remains has shown they ate leaves, particularly fronds from ferns, a conclusion backed up by the shapes of their beaks (James, 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 Hawaiian raspberry or ʻākala - suggests that the Cyanea evolved these thorn-like prickles on new growth as protection against browsing by the Moa-nalo. The Moa-nalo themselves filled the niche of herbivore usually filled by mammals such as goats and deer, or the giant tortoises of the Galapagos archipelago. 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 Polynesian settlers in the islands, along with many other species, including a native eagle, owls, several species of flightless ibis, a large number of flightless rails, and many of the honeycreepers. Like island faunas from Mauritius, New Zealand and Polynesia, they were unused to mammals and were easily taken by hunters or the animals that were introduced.

[edit] See also

• Giant tortoise from several archipelagoes around the world.
• Moa are enormous extinct flightless birds, formerly the largest herbivores in New Zealand.

[edit] References

• Hawaiian Birds: Lessons from a Rediscovered Avifauna B. Slikas, Auk 2003
• The diet and ecology of Hawaiʻi's extinct waterfowl: evidence from Coprolites, H. James, Biological Journal of the Linnean Society 1997
• Relationships of the extinct moa-nalos, flightless Hawaiian waterfowl, based on ancient DNA, Sorenson et al, Proceedings of the Royal Society 1999de:Moa-Nalos