Wednesday, August 18, 2010

Prehistoric Penguins

Waimanu, the first penguin


How long have penguins been around?  I suspect that most people would respond that they seem relatively young, in the grand scheme of things.  Penguins are so unique, and they seem particularly modern because of their constant presence in ads and movies.  There is also that constant mental association with icy environments that makes it hard to picture them along a steamy Paleocene coastline.

Waimanu is currently the oldest known penguin, and it is an ancient taxon indeed.  The rocks containing the Waimanu manneringi holotype skeleton are an astounding 61.6 million years old, far and away the oldest to produce penguin bones. A close relative, the smaller Waimanu tuatahi is found in rocks 58-60 million years old. To put this in perspective, these penguins lived just 4-5 million years after the mass extinction that killed off the dinosaurs (except for birds of course).
The first fossils of this taxon were collected almost 20 years ago by Al Mannering, in whose honor the first species is named.  Both come from the Waipara Greensand, a unit of sedimentary rocks laid down in nearshore waters during the Paleocene in present down North Canterbury.  During the Paleocene, this area of the South Island of New Zealand was submerged, and penguins, plankton and shellfish often became entombed in the dark sandy sediments upon death. Millions of years later, these rocks and their trove of fossils were exposed as tectonic forces lifted the ancient seafloor up to the sun and the Waipara River cut away the overlying layers.

These early penguins inherited a world in which a reset button had been firmly pressed. It was warm, rather homogenous in temperature across most of the latitudinal gradient, and most importantly, nearly every major niche was hung generously with “help wanted” signs.  For much of the Mesozoic, dinosaurs dominated terrestrial ecosystems and large marine reptiles occupied the aquatic tetrapod predator niche.  Mosasaurs, plesiosaurs and pliosaurs swam the seas worldwide.  But at the end of the Cretaceous, an asteroid impact wiped out all of these groups.  Even sharks were decimated, though of course some survived to re-supply our oceans and imaginations with toothed nightmares.

This extinction spelled opportunity for many groups.  Mammals radiated into the void left by dinosaurs, and some dinosaurs got a new opportunity.  The volant (flying) ancestors of penguins had a window in which the seas were free of largely free of competitors and low on predators.  This was a perfect time to drop flight altogether.  By 60million years ago, Waimanu manneringi and Waimanu tuatahi, two closely related species, had reached this critical stage in penguin evolution.

A reconstruction of Waimanu tuatahi from Slack et al. (2006).

Waimanu is both amazingly penguin-like and amazingly primitive.  Waimanu manneringi was a healthy size, about halfway between a King Penguin and an Emperor Penguin in standing height, while Waimanu tuatahi was a bit smaller, about 2 1/2 feet (80cm) tall. Waimanu manneringi is only known from a single hindlimb and pelvis, while specimens of Waimanu tuatahi is much more complete – multiple specimens together combine to give us almost the entire skeleton.  From head to toe, the skeleton of Waimanu combines primitive and derived characters.  The skull exhibits the long, narrow beak seen in other early fossil penguins rather than a stubbier modern penguin beak.  The flipper is much shorter than the wing of a flighted bird, but significantly longer relative to the body than in living penguins (indicating it would have a lower wing load).  The bones are also more flattened than flighted birds but less flattened than living penguins, which have highly compressed bones to form a more knife-like wing profile.  In the hindlimb, Waimanu is very close to modern penguins.  The shape of the limb bones indicate an upright posture like modern penguins employ, and the feet are short and stubby.  So Waimanu walked like a penguin on land, swam like a less-efficient penguin in the water, and probably ate the same basic foods (perhaps a little fish heavy).  There is a lot more to say about these fascinating species, but I will await some upcoming work by the Waimanu team to cover that story.

In closing, I should point out that the title of this post is actually a bit inaccurate. Waimanu manneringi is in fact the oldest penguin we know of. But, it is highly unlikely it was actually the first penguin.  The rock record is incomplete, and there is a roughly 10 million year gap between Waimanu tuatahi and the next oldest penguin fossil, showing we are missing big pieces of penguin history – probably on both sides of the 60 million year mark.

The closest relatives of penguins that are alive today are the Procellariiformes, the group that includes albatrosses and petrels.  These birds are commonly called tubenoses because their nostrils take the form of short tubes instead of flat openings. Most likely, the penguin lineage and the tubenose lineage split off from one another and started on their own evolutionary paths deeper in time, perhaps even during the Cretaceous Period. At this deep split, the birds heading off along the evolutionary trajectories to modern penguins and modern petrel probably looked a lot more like a petrel than a penguin – certainly volant (capable of flight) and probably with a similar ecology to some modern tubenose birds.  Whether we would call the bird on the penguin side of the split a “penguin” is debatable – it would probably be very hard for us to recognize a fossil penguin in the rock record until, like Waimanu, they evolved  a flightless lifestyle.  So, pending the discovery of a mind-bending fossil of a flying penguin, we’ll let Waimanu revel in its place in the sun.

References: Slack, K.E., C.M. Jones, T. Ando, G.L. Harrison, R.E. Fordyce, U. Arnason, and D. Penny. 2006. Early Penguin Fossils, Plus Mitochondrial Genomes, Calibrate Avian Evolution. Molecular Biology and Evolution 23: 1144-1155.

Source


Fossil Penguins

Waimanu - 60-million year old penguins from New Zealand

R Ewan Fordyce

An online article recently published in the journal Molecular Biology and Evolution (March 2006) recognises a new genus of ancient penguin (Waimanu) from New Zealand rocks some 60-62 million years old. The ancient penguins lived in shallow seas off eastern New Zealand in Paleocene times, only a few million years after the extinction of dinosaurs. These "proto" penguins were about the size of living yellow-eyed penguins. They probably looked a bit like shags (cormorants), but had compressed and dense wing bones, allowing wings to be used to swim underwater. It is most unlikely that the Waimanu penguins could fly in air. These fossils are a little older than archaic penguins from Tierra del Fuego, documented by Dr Julia Clarke and coauthors (2003), and are the oldest fossil penguins reported from New Zealand.

Waimanu Paleocene_penguin
The reconstruction shown here, by Chris Gaskin, is © Geology Museum, University of Otago.
Waimanu humerus
Ewan Fordyce shows the position of the humerus, or upper wing bone, on a reconstruction of Waimanu tuatahi.
Photo by R Ewan Fordyce; reconstruction ©Geology Musuem, University of Otago.
Waimanu reconstruction
Reconstruction by G. Gaskin, showing 3 individuals of Waimanu tuatahi on a New Zealand beach in Paleocene times, 58-60 million years ago. Reconstruction ©Geology Museum, University of Otago.

Because the Waimanu penguins are well dated in terms of geological age, it is possible to use that known age to calibrate a new molecular phylogeny - or pattern of relationships - for living birds. The phylogeny shows a branching pattern of bird relationships based on study of genetic material from a range of living birds such as storks, albatrossses, ducks and moas. By using the dates from the fossil Waimanu penguins as a calibration point, we can then predict how far back in time the other groups of living birds originated. If early penguins lived in southern seas not long after the extinction of dinosaurs, then other bird groups more distantly related to penguins must have been established even earlier.

The study suggests that many groups of living birds originated well back in Cretaceous times, when dinosaurs were thriving - thus, many modern lineages had ancient origins. Such a notion conflicts with an idea suggested by Professor Alan Feduccia (1995, 2003), who suggested that many living bird groups are geologically young, and mostly represent groups that arose after dinosaurs went extinct.

Feduccia argued that most birds from Cretaceous times - from the age of dinosaurs - were ancient lineages not related to living forms. He suggested that those ancient bird groups disappeared, along with dinosaurs, in a turnover at the catastrophic "KT boundary" extinction 65 million years ago. Feduccia also suggested that there was a complete new evolutionary radiation of "modern" birds following the KT extinction.

Now, the new study which combines fossils and molecular approaches, predicts that "modern" birds thrived in the age of dinosaurs. We expect that the fossil record will continue to produce the hard evidence of those birds.

Details of title and authorship

Early Penguin Fossils, plus Mitochondrial Genomes, Calibrate Avian Evolution Kerryn E. Slack1 , Craig M. Jones2 , Tatsuro Ando3 , G. L. (Abby) Harrison4, R. Ewan Fordyce3, Ulfur Arnason5, and David Penny4
  1. Allan Wilson Center for Molecular Ecology and Evolution Institute of Molecular BioSciences Massey University Palmerston North New Zealand; Division of Evolutionary Molecular Systematics Department of Cell and Organism Biology University of Lund Solvegatan 29 S-223 62 Lund Sweden
  2. Institute of Geological and Nuclear Sciences Lower Hutt New Zealand
  3. Department of Geology, University of Otago Dunedin New Zealand
  4. Allan Wilson Center for Molecular Ecology and Evolution Institute of Molecular BioSciences Massey University Palmerston North New Zealand
  5. Division of Evolutionary Molecular Systematics Department of Cell and Organism Biology University of Lund Solvegatan 29 S-223 62 Lund Sweden
Abstract
PDF
The first specimen of Waimanu was found in the 1980s, by Brad Field (then of NZ Geological Survey), and was passed to Ewan Fordyce for study. Craig Jones prepared the specimen - now curated in the Geology Museum of University of Otago - while working for Fordyce as a technician. Fordyce and Jones (1990) later published some details of the first fossil. Subsequently, Al Mannering (of Christchurch, affiliated with Canterbury Museum) discovered more Paleocene penguins (Jones and Mannering 1997) which Mannering prepared; those fossils are curated in Canterbury Museum, Christchurch. Most recently, the Waimanu fossils have been studied in detail by Geology graduate student Tatsuro Ando, as part of his PhD studies at University of Otago. Al Mannering's sterling efforts of collecting and preparation are honoured in the name of one of the species, Waimanu manneringi.
For details of molecular studies, contact Professor David Penny of Massey University.

References

Clarke, J. A., Olivero, E. B., and Puerta, P. 2003. Description of the earliest fossil penguin from South America and first Paleogene vertebrate locality of Tierra del Fuego, Argentina. American Museum Novitates (3423): 1-18.
Feduccia, A. 1995. Explosive evolution in Tertiary birds and mammals. Science 267 (5198): 637-8.
Feduccia, A. 2003. 'Big bang' for tertiary birds? Trends in Ecology & Evolution 18 (4): 172-176.
Fordyce, R. E. and Jones, C. M. 1990. The history of penguins, and new fossil penguin material from New Zealand. Pages 419-446 in Davis, L. S. and Darby, J. D. (editors), Penguin biology. Academic Press, San Diego. 467 p.
Jones, C. M. and Mannering, A. 1997. New Paleocene fossil bird material from the Waipara Greensand, North Canterbury, New Zealand. Geological Society of New Zealand miscellaneous publication 95a: 88.
Simpson, G. G. 1971. A review of the pre-Pliocene penguins of New Zealand. Bulletin of the American Museum of Natural History 144: 321-378.

Source

The first fossil penguin – Palaeeudyptes antarcticus Huxley 1859, from Kakanui, North Otago

By R.Ewan Fordyce

The first fossil penguin recognised to science was an incomplete but dramatically large ankle bone from Kakanui, in coastal Otago. The bone was acquired by Government Agent Walter Mantell during his travel along the Otago coast in late 1848, and was sent to Britain where it was studied by the pre-eminent paleontologist T.H. Huxley. Huxley announced the find in the Quarterly Journal of the Geological Society in March 1859. There he identified the bone as from a new genus and species of penguin which he named Palaeeudyptes antarcticus – literally, ancient winged diver of the south. The ankle bone or tarsometatarsus is perhaps the single most distinctive bone in penguins and, had he been presented with some other bone, Huxley might have found it more difficult to convince people that the fossil was from a penguin.

Huxley woodcut 1859
Huxley's original illustration of the ankle bone is reproduced here. The left figure shows a front view; the right figure, the back view. One trochlea, or projection for a toe, is missing – from the right side of the front view.

penguin bones
Illustrations of penguin bones produced for James Hector's 1872 article on fossil penguins.
Within a few decades, other fossil penguin bones were reported from New Zealand, both from North Otago and from Westland. Again, the bones clearly represented species larger than those of today. Because of their size, the fossils were thought to represent more individuals of Huxley's new species, Palaeeudyptes antarcticus. However, no ankle bones were known amongst the new specimens, and it could not be confirmed that all the fossils really did represent the one species. Indeed, despite 150 years of field work, no more material of Huxley's species has been found – the species Palaeeudyptes antarcticus is indeed known from one incomplete bone. So, the name can be used confidently only for the one fossil which resides in a drawer in the Natural History Museum, London. Finally, we aren’t even sure of the age of the fossil; it is probably from the soft white Ototara Limestone which, at Kakanui, spans the Eocene/Oligocene boundary – in the range 32-34 M years. However, the bone could be from the harder and younger Otekaike Limestone, with an age of perhaps 23-24 M years.

The lack of complete specimens was not going to spoil a good story. The early finds quickly led to speculation that ancient penguins were giants, with body heights perhaps reaching "eight feet" (about 2.4 m). In 1975, renowned fossil penguin expert G.G. Simpson reviewed penguin body size, and concluded that even the most massive New Zealand penguin, Pachydyptes ponderosus, was much smaller - at 1.43-1.62 m.

Other new discoveries from the Waitaki Valley region show that there was quite a range of body size represented amongst penguins – not all were giants. Species of Platydyptes, for example, probably stood a little taller than a living yellow-eyed penguin (Megadyptes antipodes), and several fossils of tiny penguins – the size of little blues (Eudyptula minor) are known.

Our collections of penguin fossils are under study by PhD student Tatsuro Ando, as part of his research on the origin of penguin flight.

Remarkably complete skeletons of Palaeeudyptes-like penguins are sometimes on display in the Geology Museum, University of Otago. (The Geology Museum is open to the public 9am – 5 pm weekdays; access is via the Quadrangle.) Less complete but equally large specimens also may be seen at Otago Museum.

There are significant displays in North Otago that relate to fossil penguins. A poster reviewing these birds is in the Blue Penguin Visitor Centre in Oamaru. Interpretive graphics, casts and original fossils are displayed in the Vanished World Centre, Duntroon.


Tatsuro Ando studying fossil and modern penguin skulls.

Cast of Mantell's original ankle bone on the left; original fossil of a Palaeeudyptes-like penguin on the right. Both specimens from Geology Museum, University of Otago.

References for further reading

  • Fordyce, R.E. and Jones, C.M. 1990. The history of penguins…. Pages 419-446 in Davis, L.S. and Darby, J.D. (editors), Penguin biology. Academic Press, San Diego. 467 p.
  • Gaskin, C. and Peat, N. 1991. The world of penguins. Hodder and Stoughton, Auckland. 48 p. (Non-technical.)
  • Hector, J. 1872. On the remains of a gigantic penguin (Palaeeudyptes antarcticus, Huxley) from the Tertiary rocks on the west coast of Nelson. Transactions and proceedings of the New Zealand Institute 4: 341-346.
  • Huxley, T.H. 1859. On a fossil bird and a fossil cetacean from New Zealand. Quarterly journal of the Geological Society of London 15: 670-677.
  • Marples, B.J. 1952. Early Tertiary penguins of New Zealand. New Zealand Geological Survey paleontology bulletin 20: 66 p.
  • Peat, N. 1992. Penguins from the past. Forest and bird 23 (1, February): 32-34. (Non-technical.)
  • Simpson, G.G. 1975. Fossil penguins. Pages 19-41 in Stonehouse, B. (editor), The biology of penguins. MacMillan, London. 555 p.
  • Simpson, G.G. 1976. Penguins past and present, here and there. Yale University Press, New Haven. 150 p. (This is an excellent introductory text.)
Source

4 comments:

Ross Mounce said...

How about a mention for Clarke et al 2007? Or the review of fossil penguins given in Jadwiszczak 2009?



Clarke, J. A., Ksepka, D. T., Stucchi, M., Urbina, M., Giannini, N., Bertelli, S., Narváez, Y., and Boyd, C. A. 2007. Paleogene equatorial penguins challenge the proposed relationship between biogeography, diversity, and cenozoic climate change. Proceedings of the National Academy of Sciences 104:11545-11550.

Jadwiszczak, P. 2009. Pol. Polar Res. 30 (1): 3–28
http://polish.polar.pan.pl/ppr30/PPR30-003.pdf

wiinterrr said...

Hi Ross,

Consider it done with your commentary; however, I would contact the University of Otago in order to facilitate their own information. They are the folks who first published the articles posted here in this particular post.

Your own knowledge appears extensive regarding fossil penguins and I'm very glad to have you as a reader here. :)

Ross Mounce said...

sorry about that. I didnt realise the articles were re-posts. That explains why all the articles mentioned are so Otago-centric...

wiinterrr said...

No problem. I'm always learning about prehistoric penguins and so the articles that fascinate me are the ones I post here. I suppose you could call this blog a collection on current knowledge on the science of penguins.

But thanks for the link to Jadwiszczak's paper. Very informative. And I'm very glad for your comments.