Kairuku is an extinct genus of penguin.[1] It contains three species, K. grebneffi, K. waitaki [2] and K. waewaeroa.[3] This taxon is known from bones from 27 MYA (late Oligocene), from the Kokoamu Greensand Formation of New Zealand.[1] It was historically referred to as Palaeeudyptes.[1]
| Kairuku Temporal range:
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|---|---|
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| Artist's impression of Kairuku | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Sphenisciformes |
| Genus: | †Kairuku Ksepka, Fordyce, Ando & Jones, 2012 |
| Type species | |
| Kairuku waitaki | |
| Species | |
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Etymology
editThe genus name Kairuku comes from the Māori words kai (“food”) and ruku (“to dive”).[1]
The species name waewaeroa is from Māori waewae - "legs", and roa - "long", referring to the elongated hind limbs.[3]
K. grebneffi was named after Andrew Grebneff, a paleontologist from the University of Otago who died in 2010.[4]
Distribution
editThe fossils of Kairuku waewaeroa were found within the Glen Massey formation (34.6–27.3 Ma) in the North Island of New Zealand.[3]
Description
edit
Kairuku is one of the most completely known genus of Paleogene penguins. Described species are larger than modern emperor penguin which stood around a meter,[1] K. grebneffi stood 1.28 metres (4.2 ft) tall,[1] and K. waewaeroa is even larger with height up to 1.38 metres (4.5 ft).[3] Unnamed species called Glen Murray fossil penguin is estimated to have a height 2 to 20% taller than K. grebneffi.[5]
Kairuku grebneffi
editKairuku grebneffi were nearly 1.5 metres (4.9 ft) long and stood 1.3 metres (4.3 ft) tall.[4] Adult individuals weighed an estimated 60 kilograms (130 lb), 50% more than modern emperor penguins.[6] K. grebneffi had the longest humerus bone of any penguin extant or attested to in the fossil record.[4] The bird had a longer bill and more slender body compared to living penguins.[7] Relative to its body size, its flippers were longer and probably more flexible than those of extant species.[7][8] The bird had short, thick legs, but overall, looked much like a modern penguin "from a distance."[7][8] K. grebneffi is distinguished from its sister species K. waitaki primarily on the basis of vertebrae spacing and by having a straight tipped bill, compared to the curved tip of K. waitaki.[4] Additionally, all known specimens of K. grebneffi are larger, although small sample size prevents that from being a diagnostic characteristic.[4]
K. grebneffi likely used its slender beak to spear fish and squid.[7] It likely was able to dive deeper and swim farther than living penguins.[6] Predators of the bird likely included sharks and Squalodons.[7]
K. grebneffi lived in what is now New Zealand late in the Oligocene period, roughly 25–27 million years ago.[6] At the time, most of the area was ocean, with a few isolated islands.[6] It is believed that these rock outcrops provided safe breeding grounds and easy access to rich food resources in the surrounding seas.[6] K. grebneffi lived alongside at least four other penguin species. It is likely that each species fed on different kinds of fish.[9]
K. grebneffi was among of the last of the giant penguins.[7] The cause of K. grebneffi's extinction is unknown, but was probably related to "the drastic change in paleoenvironment" according to Tatsuro Ando, one of the scientists who classified the penguin.[7] Other possibilities include the arrival of new predators and increased food competition.[6]
Kairuku waewaeroa
editThe skeleton of the holotype is one of the most complete skeletons of giant penguins that have ever been found. Phylogenetic analysis reveals a clade that unites[clarification needed] New Zealand endemics Kairuku waewaeroa, Kairuku waitaki and Kairuku grebneffi. The probable height of K. waewaeroa is 1.38 m (4.5 ft), and the length of the body from the fingertips to the tip of the beak is 1.6 m (5.2 ft).[3][10]
Discovery
editThe first Kairuku bones were discovered in 1977 by Ewan Fordyce, although they were not identified as such at the time.[6][11] In February 2012, an international team of scientists led by Fordyce and Daniel Ksepka reconstructed a K. grebneffi skeleton using a few "key specimens" from the Kokoamu Greensand of the North Otago and South Canterbury districts of New Zealand.[4][6] The specimens used represent some of the most complete skeletons found of any extinct penguin, and thus provide valuable insight into the reconstruction of all extinct penguins.[4] The king penguin was used as a guide during reconstruction.[6]
The holotype of K. grebneffi was collected in 1991 from a drainage area of the Waipati stream, a tributary of the Maerewhenua River.[4]
Fossil remains of Kairuku waewaeroa, or Kawhia giant penguin, fossil remains were found in Kawhia Harbour on the North Island of New Zealand.[3][12]
External links
editReferences
edit
- ^ a b c d e f Ksepka, Daniel T.; Fordyce, R. Ewan; Ando, Tatsuro; Jones, Craig M. (March 2012). "New fossil penguins (Aves, Sphenisciformes) from the Oligocene of New Zealand reveal the skeletal plan of stem penguins". Journal of Vertebrate Paleontology. 32 (2): 235–254. Bibcode:2012JVPal..32..235K. doi:10.1080/02724634.2012.652051. JSTOR 41515052. S2CID 85887012.
- ^ Giant Prehistoric Penguin was Bigger Than an Emperor | Observations, Scientific American Blog Network
- ^ a b c d e f Giovanardi, Simone; Ksepka, Daniel T.; Thomas, Daniel B. (16 September 2021). "A giant Oligocene fossil penguin from the North Island of New Zealand". Journal of Vertebrate Paleontology. 41 (3): e1953047. Bibcode:2021JVPal..41E3047G. doi:10.1080/02724634.2021.1953047.
- ^ a b c d e f g h Ksepka, Daniel T.; Fordyce, R. Ewan; Ando, Tatsuro; Jones, Craig M. (March 2012). "New fossil penguins (Aves, Sphenisciformes) from the Oligocene of New Zealand reveal the skeletal plan of stem penguins". Journal of Vertebrate Paleontology. 32 (2): 235–254. Bibcode:2012JVPal..32..235K. doi:10.1080/02724634.2012.652051. JSTOR 41515052. S2CID 85887012.
- ^ Thomas, DB; Ksepka, DT (1 October 2016). "The Glen Murray fossil penguin from the North Island of New Zealand extends the geographic range of Kairuku". Journal of the Royal Society of New Zealand. 46 (3–4): 200–213. Bibcode:2016JRSNZ..46..200T. doi:10.1080/03036758.2016.1211541. ISSN 0303-6758. S2CID 132811234.
- ^ a b c d e f g h i "Scientists reconstruct 'elegant' giant penguin that lived in New Zealand 26 million years ago". Dawn. Associated Press. 1 March 2012. Archived from the original on 6 July 2021. Retrieved 1 March 2012.
- ^ a b c d e f g Viegas, Jennifer (27 February 2012). "Ancient Penguin Weighed 130 Pounds". Discovery News. Discovery Channel. Archived from the original on 23 April 2012. Retrieved 1 March 2012.
- ^ a b "Fossils show huge penguin once roamed New Zealand". Bangkok Post. Agence France-Presse. 28 February 2012. Archived from the original on 12 October 2021. Retrieved 1 March 2012.
- ^ Dell'Amore, Christine (27 February 2012). "Giant Prehistoric Penguins Revealed: Big but Skinny". National Geographic News. Archived from the original on 22 March 2016. Retrieved 1 March 2012.
- ^ "A mega-penguin stood tall on prodigious limbs". Nature. 597 (7878): 597. 21 September 2021. Bibcode:2021Natur.597R.597.. doi:10.1038/d41586-021-02562-y. S2CID 237594320.
- ^ "Kairuku - a new "giant" Late Oligocene Penguin from New Zealand". University of Otago. 23 November 2015.
- ^ Wetzel, Corryn (17 September 2021). "New Zealand Kids Discovered This Fossil of New Giant Penguin Species on a Field Trip". Smithsonian Magazine. Archived from the original on 22 September 2021. Retrieved 19 September 2021.