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DISPLAYING POSTS TAGGED: evolution (8)

Bill Bailey, birdwatcher

Author
by Kate C
Publish date
13 September 2012
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UK comedian, musician and birdwatcher Bill Bailey is in Melbourne this week as part of his Qualmpeddler tour of Australia and New Zealand. Yesterday he, and fellow comedian and ornithology buff Jeff Green, visited collection stores and exhibitions at Melbourne Museum.

Bill and Jeff in collection store Bill Bailey and Jeff Green in the Ornithology collection store at Melbourne Museum.
Image: Ben Healley
Source: Museum Victoria
 

It’s all thanks to a timely radio broadcast: PhD student Darren Hastie heard an interview in which Bill talked about being a fan of Alfred Russel Wallace, co-originator (with Charles Darwin) of the theory of evolution by natural selection. Learning this, collection manager Rolf Schmidt sent a message to Bill via his website to tell him that Museum Victoria holds a number of specimens collected by AR Wallace, and to invite him to come and see them.

Bill is not just a fan of Wallace; he is the patron of the Wallace Fund which works to give the great naturalist due credit for his contributions to our understanding of evolution. Bill has spent five years researching Wallace’s life and work, which will culminate in a BBC documentary in 2013. Next year marks a century since Wallace’s death and, if all goes to plan, will also see a portrait and statue of Wallace erected in the Natural History Museum in London to equal its famous marble statue of Darwin.

Bill Bailey in collection store Bill Bailey opening the cabinet filled with bird specimens collected by AR Wallace, saying, “This is why I love museums. You think, what’s in here? Then OH MY GOD…”
Image: Ben Healley
Source: Museum Victoria
 

Having recently returned from filming the Wallace documentary in Indonesia, Bill swapped tales with ornithologist and collection manager Wayne Longmore about the bizarre fauna found in Sulawesi, Indonesia, due to what is now called the Wallace Line. To the west of the line, Asiatic species predominate, while to the east, Australian lineages appear. Sulawesi is right in the thick of it and its animals are an amazing assortment of both origins. For eight years, Wallace travelled through Malaysia and Indonesia collecting birds, insects and more, and it was his astute observations of the patterns of species distribution that spawned the science of biogeography, and helped him develop his theory of evolution.

Poor Wallace, however, has been obscured by time and the greater profile of Darwin. Said Bill, “Wallace was an extraordinary field naturalist, probably one of the greatest. And he hasn’t got the recognition he deserves. He needs to be mentioned in the same breath as Darwin, or at very least get equal billing.” Darwin had been working on his theory of natural selection for many years but it wasn’t until 1858, when Wallace sent him his own fully-articulated theory, that Darwin was prompted to stop thinking and get down to the business of publishing. The two presented their theory together at a meeting of the Linnaean Society. As Bill said, “at the time it known as the Darwin-Wallace theory, but when it was revived in the 30s, Wallace’s name was gone.” Jeff in turn suggested that the Australian city of Darwin switch its name to Darwin-Wallace for 2013 for the centenary.

After viewing the Wallace specimens in the ornithology store, Bill and Jeff visited the Science and Life Gallery where the Darwin to DNA exhibition has Wallace-collected skins and mounts on display, complete with his original hand-written tags. Next Rolf took them to down to the palaeontology collections and labs. Rolf reports, “Bill was quite interested in the size and scope of our collection, as well as the stories around the objects (like the Janjucetus skull). He was also rather excited when I let him have a hold of our Darwin barnacle holotype.”

Visiting the palaeontology collections L-R: Darren Hastie (PhD student and fellow AR Wallace fan), Rolf Schmidt, Jeff Green (kneeling), Bill Bailey and Dave Pickering amid the Palaeontology collection.
Source: Museum Victoria
 

Bill’s fascination with Wallace is infectious - and he certainly loves museums. He says he always tries to visit the natural history museums of the cities where he performs. We’re very glad he dropped in to visit us, and will watch with interest as the Wallace100 plans unfold.

Links:

The Wallace Fund

Stories from the filming of the Wallace documentary on the Wallace100 blog (via Natural History Museum)

MV Blog: Wonderful Wallacea

MV Blog: Happy birthday A.R. Wallace

First fossil of Pygmy Right Whale

Author
by Kate C
Publish date
10 August 2012
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The Pygmy Right Whale (Caperea marginata) is the oddball of the whale world. The bizarre anatomy of this species has confounded researchers for years – even its common name demonstrates our historical lack of understanding. Its arched upper jaw and skim-feeding behaviour is similar to the right whales however DNA analysis shows that Pygmy Right Whales are more closely related to the rorquals (family Balaenopteridae) than the true right whales (family Balaenidae).

The puzzle of the evolutionary history of this species was not helped by the fact that it appeared completely absent from the fossil record. Palaeontologist and whale expert Erich Fitzgerald was therefore extremely pleased to identify a lone fossil specimen in the Museum Victoria as a partial periotic (the bone that surrounds the inner ear) of an ancient relative of the Pygmy Right Whale.

One theory about this group, explains Erich, is that "the bizarre features of the Pygmy Right Whale evolved rapidly within the last three to four million years. But this fossil suggests that they're much older than that." The specimen, which Erich describes as "looking like a coconut," is larger than the periotic of the living Pygmy Right Whale and dates to the late Miocene. This makes it six million years old, which will help calibrate the whale phylogenies (evolutionary trees) that are based on DNA sequences.

four views from different angles of whale earbones. Comparison of the incomplete fossil specimen (left) with a complete earbone of a juvenile Pygmy Right Whale.
Image: Erich Fitzgerald
Source: Museum Victoria / Journal of Vertebrate Paleontology

 
It is the peculiar skeleton of the Pygmy Right Whale, particularly of its ear bones, that allowed Erich to identify such an odd and incomplete fossil. "Baleen whales in general have strange skulls but in Pygmy Right Whales the ear bones are particularly strange because the back end, of the periotic, is enormous and bulbous. This fossil has no features that would ally it with any other family."

The strangeness of this whale doesn't end with its skull. First up, there is its size; at just 6.5 metres long, it's the smallest living baleen whale. Compare this with its colossal distant relatives, such as the 33 metre Blue Whale. But there's more, says Erich. "If we look beyond the head, there are some really strange things. In particular, the Pygmy Right Whale has ribs that are flattened and expanded. It almost looks like the ribs have formed a shield over the organs." This may relate to their unusual way of swimming which requires a stiffer trunk. "A young animal filmed underwater in South Africa shows that they flex their entire body not just the tail. It's thought that the ribs may be expanded to help keep the body rigid during this movement."

Until this footage, almost all knowledge of the species came from stranded individuals. Recent aerial photographs of a pod of Pygmy Right Whales off the coast near Portland showed some kind of social behaviour but exactly what it is – feeding, reproducing or something else – is still unknown.

Museum of New Zealand Te Papa Tongarewa made this video with a dissection of a stranded whale which clearly shows the unusual ribs.

 

Links:

Erich M. G. Fitzgerald. 2012. Possible neobalaenid from the Miocene of Australia implies a long evolutionary history for the pygmy right whale Caperea marginata (Cetacea, Mysticeti). Journal of Vertebrate Paleontology 32(4): 976-980. DOI:10.1080/02724634.2012.669803

The Tetrapod Zoology blog has a series of three terrific posts about Pygmy Right Whales:
Caperea is really weird
More on little Caperea
Caperea alive

Happy Darwin Day

Author
by Ursula
Publish date
11 February 2012
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Comments (3)

Ursula Smith works in the natural sciences collections at Museum Victoria. Though a palaeontologist by training she finds all the collections fascinating and swings between excitement at all the cool stuff in them and despair at the lack of time to look at it all.

February 12th is Charles Darwin's birthday, now celebrated at institutions around the world as Darwin Day. Darwin's work is obviously relevant to a lot of the research that goes on at Museum Victoria today, but we also have a direct link with him through some specimens housed in the Palaeontology Department.

Charles Darwin in 1854 Charles Darwin in 1854
Source: Out of copyright, via Wikipedia.
 

Darwin's best-known work is The Origin of Species, and if you had to name the animals he was particularly interested in, you'd probably think finches, or perhaps tortoises. But these are just the tip of the iceberg; before, and after publishing The Origin, Darwin also published prolifically across a breadth of natural history subjects, including geology, zoology, ornithology, entomology and botany. All of this work was vital, both in developing his theory of evolution by natural selection, and in gaining him a wide and interested audience.

One of the lynchpins of Darwin's theory was homology, the sharing of characters due to common descent (meaning that if two species share a feature we assume, until we can show otherwise, that they both inherited it from their common ancestor). Much of Darwin's thinking about homology was developed through his detailed study of the humble barnacle. He published the first full treatment of barnacles in the early 1850s with four monographs on modern and fossil barnacles.

Over 100 years later in the 1960s, the then Curator of Palaeontology at Museum Victoria, Thomas Darragh, noticed that some of the specimen labels in the palaeontology collection had handwritten notes saying "Original figured by Darwin".

Specimen label written by Kranz. Specimen label written by Kranz.
Source: Museum Victoria
 

Going back to Darwin's original descriptions and illustrations, Dr. Darragh confirmed that these specimens matched Darwin's material. For instance, looking at this photo of Scalpellum simplex and the original illustration, it's clear that the illustration is of this specimen – they share the same broken tip even though the figure shows the specimen free of the rock. Similarly, the other specimens are close matches to those in Darwin's monographs.

  Barnacle Scalpellum simplex Darwin 1854, illustration and fossil Left: Extract of plate from Darwin's original monograph. | Right:Fossil barnacle Scalpellum simplex Darwin 1854. Scale bar = 1cm. (NMV P133334).
Image: Charles Darwin | Thomas Watson
Source: Out of copyright | Museum Victoria
 

A little more investigation showed that all of the specimens Dr. Darragh had found had been declared lost by Thomas Henry Withers in the 1930s when he compiled a catalogue of the barnacle material at the Natural History Museum in London (then the Natural History section of the British Museum). So the specimens that had been thought lost for over 30 years were now found, but how had they come to be in Melbourne instead of London?

In 1854 when his work on barnacles was complete, Darwin donated all the material that he had collected himself to the British Museum, where, 80 years later, Withers made his catalogue. However, Darwin also borrowed from other collectors. One of these was John Morris, a mollusc specialist possibly best known for The Catalogue of British Fossils and who went on to become professor of Geology at University College London. When he donated his own collection, Darwin returned Morris' material to him. Morris later sold his collection to the German fossil dealer, August Krantz who, for some reason, discarded all of the original labels and re-wrote them.

In 1863, Frederick McCoy, the first director of Museum Victoria (then known as the National Museum of History and Geology) bought a collection of fossils from Krantz for the museum.

This was just one of many purchases of fossils and minerals that McCoy made from Krantz, but this one happened to include at least part of Morris' collection, including the barnacles that Darwin had worked on. Since nobody was actively working on barnacles, it took 100 years for anyone to realise the importance of these specimens, but since we did the specimens have been housed safely in the museum's type collection accessible for researchers around the world.

Happy Darwin Day!

Links:

Darwin Online Project 

Darwin's barnacle studies (Darwin Online Project)

Invertebrate Palaeontology Collections

Infosheet: How do barnacles cement themselves to rocks?

Maximum rate of mammal evolution

Author
by Kate C
Publish date
30 January 2012
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"How fast can a mammal evolve from the size of a mouse to the size of an elephant?" This question introduces a new paper published today by a group of international researchers led by Alistair Evans of Monash University, including Dr Erich Fitzgerald, Senior Curator of Vertebrate Palaeontology at MV.

The world's largest mammal by weight, the Blue Whale, is about 61 million times heavier than the world's smallest, the Etruscan Shrew. Erich and his colleagues are interested in how such a range of body sizes evolved within the mammals, particularly the rate at which such evolution occurs.

Previous investigators have calculated rates of evolution using narrowly-defined parameters, whether within a shorter time scale or within a limited taxonomic group. This study is the first to tackle the larger picture, using data from a variety of species that lived over the last 70 million years.

The researchers found that it takes a minimum of 1.6 million generations for terrestrial mammals to increase their mass 100-fold. To increase by 5,000-fold, it takes at least 10 million generations.

In contrast, the researchers found that land mammals can decrease in size more than ten times faster than the time it takes to increase to the same degree. Hypothetically, it could take 5 million generations for a species to evolve from rabbit size to elephant size, whereas in just half a million generations it could shrink back down again if selective pressures directed it thus. Smaller body mass gives a competitive advantage under certain conditions; this phenomenon, known as insular dwarfism, is seen in the now-extinct dwarf elephants that were stranded on Mediterranean islands by rising sea levels.

Elephant and rabbit Left: Children riding on Queenie, an Indian Elephant, at Melbourne Zoo in 1917 (MM 004061). Right: Rabbit, Oryctolagus cuniculus.
Image: Unknown | Alex J.
Source: Museum Victoria | Used under CC BY 2.0 from a_jo.
 

Interestingly, aquatic mammals such as whales evolved large body mass much faster than land mammals, taking about half as many generations to achieve the same scale of increase.

Says Erich, "Whales can get bigger because the water supports their bodies and so their maximum size is not limited by gravity." He explains that a huge body can also be an advantage for aquatic mammals because it loses less heat.

"There doesn't seem to be any slowing-down in evolution of maximum body size in whales. Land mammals may have reached a plateau enforced by gravity, but it's conceivable that the Blue Whale is not the largest possible whale. Nevertheless, energetic demands of feeding a body larger than that of a blue whale may mean that, in reality, the blue whale is as large as animals get."

Large land-dwelling mammals have a variety of solutions to the problem of gravity, explains Erich. "Some of the changes we see are extreme thickening of bones, changes in locomotion and major changes to organ systems." A gigantic rabbit wouldn't just be a large version of today's feral bunny; in fact, it would probably be unrecognisable as a rabbit. Fossils of an extinct giant rabbit described in 2011 show that it had a stiff spine to support its bulk, which meant it would not have been able to hop. Accordingly, we might need to rethink the way we portray the Easter Bunny.

Links:

Evans, A.R. et al. The maximum rate of mammal evolution. Proceedings of the National Academy of Sciences, published ahead of print on January 30, 2012.

Speed limits on the evolution of enormousness (Wired Science)

Science reveals the secrets of super-sized mammals (The Age)

Dr Erich Fitzgerald

Moles of many colours

Author
by Kate C
Publish date
25 January 2012
Comments
Comments (2)

Golden moles are burrowing mammals native to southern Africa that are completely blind. Yet, their fur produces "a rainbow of colours when viewed from various angles, much like the surface of a compact disc," according to Dr Kevin Rowe, Senior Curator of Mammals. This raises the question: why would an animal that lives in the dark, and can't see anyway, be brightly coloured? Kevin and his colleagues, including MV Research Associate Dr Karen Rowe, have published a new study in Biology Letters that considers the implications of how and why iridescence evolved.

Golden mole specimen from the Museum Victoria collection. Golden mole specimen from the Museum Victoria collection.
Source: Museum Victoria
 

Many insects, reptiles and birds use iridescence to attract mates, but this depends on keen eyesight on the part of the viewer. Analysis under scanning electron microscopy and transmission electron microscopy showed that the golden mole's colourful sheen is produced by the same mechanism as other animals: microscopic surface structures that refract light. The minute layers of scales on the surface of each hair are "most likely to reduce drag and damage while the moles swim through sand and soil," explains Karen. "The colours they produce are merely a by-product."

Four golden mole specimens Hairs from these four golden mole specimens were analysed with scanning electron microscopy and transmission electron microscopy in this study.
Source: Museum Victoria
 

The only other known example of mammal iridescence is the 'eye shine' seen when torchlight reflects from the retina of nocturnal animals, a useful trick for spotting animals in trees. With more investigation, the researchers may find other species with true iridescence and thus piece together the story of its evolution.

Links:

Holly K. Snyder, Rafael Maia, Liliana D'Alba, Allison J. Shultz, Karen M. C. Rowe, Kevin C. Rowe and Matthew D. Shawkey (2012) 'Iridescent colour production in hairs of blind golden moles (Chrysochloridae)' Biology Letters

World's first iridescent mammal discovered

Media release

The mammals of Sulawesi

Author
by Kevin Rowe
Publish date
6 January 2012
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Kevin is the Senior Curator of Mammals at Museum Victoria. He reports on his recent expedition to the mountains of Sulawesi, Indonesia in this series of blog posts.

I recently returned from an expedition into the heart of Sulawesi's central mountain forests. Shrouded in the cool moisture of clouds, these forests appear to be made of moss erupting from the ground. Halfway between Asia and Australia, the native species on this island are neither Australian nor Asian but a unique mix of lineages from the two great continents.

Cloud forest of Sulawei The mountain rainforest of Sulawesi, Indonesia.
Image: Kevin Rowe
Source: Museum Victoria
 

Together with Anang S. Achmadi, Curator of Mammals from the Museum Zoologicum Bogoriense (the national museum of Indonesia) and a team of local guides, I hiked two days from the rice fields of Mamasa to a field camp at 2600 m in the mountains above.

the Sulawesi expedition team The Sulawesi expedition team.
Image: Kevin Rowe
Source: Museum Victoria
 

campsite in Sulawesi Base camp for the Sulawesi expedition.
Image: Kevin Rowe
Source: Museum Victoria
 

Led by our local guides, including 84 year-old village-elder, Pak Daud, we encountered a pristine, primordial forest rich in biodiversity. Streams dissect the plateau spreading the daily afternoon showers across the landscape and to the fertile rice fields in the valleys below. The endangered mountain anoa (a pygmy water buffalo found only in the mountains of Sulawesi) run in large numbers, bear cuscus (relatives of Australia's brushtail possums) climb through the tree tops, dozens of orchid and pitcher plant species cling to the moss that covers everything, and a diverse assemblage of rodents survive in large numbers. We came in search of these rodents found nowhere else on earth, but which may help us understand the relationship between Australia's native rodents and Asia's.

hiking in Sulawesi Hiking through mountain terrain in Sulawesi.
Image: Kevin Rowe
Source: Museum Victoria
 

Over three weeks of surveys in these remote forests, we detected 34 species of small mammals (< 1 kg), a healthy number for any forest. Consider that there are about the same number of small mammals across the entire State of Victoria. The rodents in these mossy mountain forests are characterised by a range of morphological oddities, such as giant woolly rats, Eropeplus, small arboreal mice, Haeromys, spiny rats, Maxomys, tiny arboreal squirrels, Prosciurillus, large terrestrial squirrels, Hyosciurus, and a collection of shrew rats that, like shrews, specialise on eating invertebrates. These shrew rats include two species of the soft-furred Tateomys and one species of the short-legged Melasmothrix.

Rodents of Sulawesi. Rodents of Sulawesi. Left: small arboreal mouse Haeromys montanus. | Right: giant woolly rat Eropeplus canus
Image: Kevin Rowe
Source: Museum Victoria
 

Two species of shrew rats from Sulawesi Two species of shrew rats from Sulawesi. Left: Tateomys rhinogradoides | Right: Tateomys macocercus
Image: Kevin Rowe
Source: Museum Victoria
 

We also detected two shrew rat genera that have not been seen since the 1970s including three individuals each of the puppy-faced Crunomys and the rare, worm-eating, gangly-legged Sommeromys, previously known from a single specimen.

Two genera of shrew rats from Sulawesi. Two general of shrew rats that were found for the first time since the 1970s. Above: Crunomys sp. | Below: Sommeromys sp.
Image: Kevin Rowe
Source: Museum Victoria
 

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