Branta rhuax

[adzebill]

Jul 12, 2013 21:58:35 GMT Melanie said:

Geochen rhuax has been redescribed as Branta rhuax

Not very surprising, after all.
I guess Branta rhuax and the "undescribed large Hawai'i goose" are actually the same bird, so maybe both threads must be merged.
extinctanimals.proboards.com/thread/7851/large-hawaii-goose-unamed

[Melanie]

Yes are you are right. These taxa are now synonymised with Branta rhuax

Geochen rhuax Wetmore, 1943:146.—Olson
& James, 1991.—Livezey, 1996:417.
‘‘very large Hawaii goose’’ Olson & James,
1991.—James, 1995:98.
‘‘prehistorically extinct flightless goose’’
Giffin, 1993:1.
‘‘large, flightless goose’’ Sorenson et al.,
1999:2192.
‘‘giant Hawaii goose’’ Paxinos et al.,
2002:1399.
‘‘flightless giant Hawaii goose Branta sp.’’
Iwaniuk et al., 2004.
‘‘Branta n. sp.’’ Giffin, 2009

[Deleted]

Jul 13, 2013 11:14:59 GMT adzebill said:

I guess Branta rhuax and the "undescribed large Hawai'i goose" are actually the same bird

That would also be my question.

[Peter]

Jul 12, 2013 21:58:35 GMT Melanie said:

Geochen rhuax has been redescribed as Branta rhuax

Olson 2013. Hawaii's first fossil bird: history, geological age, and taxonomic status of the extinct goose Geochen rhuax Wetmore (Aves: Anatidae). P Biol Soc Wash 126(2): 161–168.

www.bioone.org/doi/abs/10.2988/0006-324X-126.2.161

Abstract
The history of discovery of the fossil goose Geochen rhuax Wetmore on the island of Hawaii is reviewed through archival records and the literature. Although the age of the fossil was previously undetermined, recent radiocarbon dates establish that the age of the lava flow immediately overlying the bones was 9170 ± 100 yrs b.p. A very large extinct, flightless goose that is abundant in latest Holocene lava tubes on the western versant of the island of Hawaii was previously determined by mtDNA to be part of the Hawaiian radiation of Branta. This goose is now also known from the southeastern versant of the island. Although the holotype of Geochen rhuax is somewhat smaller in size, it is considered to belong to the same species lineage as the more recent fossils, and all giant goose fossils from Hawaiian Island are here referred to as Branta rhuax, new combination.

[Peter]

If the following is true:

Although the holotype of Geochen rhuax is somewhat smaller in size, it is considered to belong to the same species lineage as the more recent fossils, and all giant goose fossils from Hawaiian Island are here referred to as Branta rhuax, new combination.

...than the radiometric date in Tyrberg (2009) can be used:

Scientific name: Branta very large undescribed species
Range: Hawai’i
Radiometric date - 14C age (years BP), ±1 σ: 510±60
Radiometric date - Calibrated date, ±2 σ: AD 1296–1485*
Direct date? Yes
Archaeological or stratigraphic association: Umi’i Manu Cave
Reference: Olson and James (1982, 1984, 1991); Giffin (2003)

An asterisk indicates that calibrated dates have not previously been published, and have been calculated for this chapter using OxCal 4.0 (Bronk Ramsey 1995, 2001).

Tyrberg, T. (2009). Holocene avian extinctions. In: Turvey, S.T. (editor) (2009). Holocene extinctions. Oxford University Press, Oxford, UK.

[surroundx]

"Bones of flightless geese found at Pu‘u Wa‘awa‘a are somewhat larger than those of the older Geochen rhuax, but have similar morphology. Because no other large flightless waterfowl were known from the Island of Hawaii, it can be assumed that G. rhuax simply increased in size over the past 10,000 years and evolved into the giant flightless goose." (p.34)

Source:

Giffin, Jon G. (2003). Pu’u Wa’awa’a Biological Assessment. Pu’u Wa’awa’a, North Kona, Hawaii. Report, State of Hawaii, Department of Natural Resources, Division of Forestry and Wildlife.