Thursday, 26 June 2014

In Search of a Penguin’s Egg. Why?...Continued

Since writing In Search of a Penguin’s Egg. Why? on 8 April, I have read more and more on antarctic exploration in order: first, to understand why Edward Wilson, chief of the scientific staff of Scott’s final (1910-1912) expedition and who died with Scott, was willing to go to such lengths to obtain embryos of the Emperor Penguin; second, to try to understand why the Falkland Islands Dependency Survey (FIDS) was still trying to collect embryos in the late 1950s. I have also found, in the literature, the fate of the embryos collected by Nelson Norman in 1959.

However, the Scott expeditions (Discovery, 1901-04; Terra Nova, 1910-1912) were not the first to collect penguin embryos. Robert Neal Rudmose Brown (1879-1957) and James Hunter Harvey Pirie (1878-1965), members of the Scottish National Antarctic Expedition led by William Speirs Bruce (1867-1924), collected embryos at different stages of development of the Gentoo (Pygoscelis papua) and Adélie (P. adeliae) penguins. These embryos were brought back to Edinburgh where they were examined by David Waterston and Auckland Campbell Geddes of the anatomy department ‘through the kindness of Dr W.S. Bruce’.

The Scottish National Antarctic Expedition left Troon on 2 November 1902. Scotia, formerly the Norewegian whaler Hekla, had been refitted for the antarctic at the now defunct Ailsa shipyard in Troon, a short distance from where I shall be teeing off from the 1st at Royal Troon at 7.50, as usual on Fridays, tomorrow morning (weather permitting, of course). This successful expedition returned on 21 July 1904 to the Marine Biological Station at Millport, now sadly reduced to a study centre for schools. I shall return to the Scottish National Antarctic Expedition later since its very existence has a bearing on later developments.


Route of the Scotia

Scotia
Waterston and Geddes wrote up their findings for the expedition’s report published on 21 October 1909.

With regard to these developmental facts the question arises:— Is the duck's or the penguin's wing the more direct descendant of the common ancestor; or have they both diverged from the common stock approximately equally, but in opposite directions. Embryology alone cannot answer this question, but the evidence is clear in this, that the fore limb of the penguin in its development goes through a progressive and continuous series of stages along one unbroken line. The mesoblastic portion of the fore limb elongates, but its characters do not alter. It elongates, however, with a relatively greater rapidity towards the end of development, whereas the duck's fore limb, after being relatively longer than the penguin's ever is, regresses rapidly. So that the answer to our question, so far as the embryological evidence is concerned, must be that the wings of both these birds are different from the ancestral wing, and that the differentiation has been in opposite directions and that the common ancestor was a flying bird of a somewhat primitive type depending in large measure for the spread of its wing upon bone and muscle.
Their conclusions could not be more clear; the ancestor of modern birds and penguins was a flying bird.
One of the two laboratories on Scotia

Bruce had placed his penguin specimens with two of the leading anatomists/embryologists in Britain. David Waterston was demonstrator in anatomy at Edinburgh. In 1909, the year of publication of the report, he went to the chair at King’s College, London but in 1914 moved to the Bute chair of anatomy at St Andrews (as a golfer he perhaps could not resist the temptation of the Old Course). He died at the age of 70 in 1942, still occupying the Bute chair.

Coats Land. The expedition named this part of the
continent for the Coats family, the sewing cotton
manufacturers (now the multinational Coats plc),
who funded the expedition.
Auckland Campbell Geddes went on to a remarkable career. At the time of the penguin work he was assistant to the Professor (only one per department in those days), D.J. Cunningham, author of the famous Manual of Practical Anatomy. On graduation in 1908, he was appointed demonstrator. He was late to qualify because he had interrupted his medical studies to serve in the Highland Light Infantry during the Boer War.

His first public achievement from 1908 lived on until recently. His suggestion that the army volunteer force should be named The Territorial Force was adopted by Lord Haldane (JBS’s uncle), then Secretary of State for War. In 1909 he went to Dublin as Professor of Anatomy and then, in 1913, to McGill University in Montreal. He returned on the outbreak of war. He rose from Major in the 17th Northumberland Fusiliers in 1914 to Brigadier-General and Director of Recruiting at the War Office in 1916-17. He was then elected Member of Parliament for Basingstoke and Andover in 1917, becoming Minister of National Service from 1917 to 1919. He was then British Ambassador to Washington from 1920 to 1923. Sadly, he lost the sight of one eye. After his recovery, he served as Chairman of Rio Tinto. in 1942 he was injured by a flying bomb and also lost the sight of his other eye. He became Baron Geddes of Rolvenden in 1942. He died in 1954, aged 74.

The collectors of the penguin eggs also became well established. Rudmose Brown (1879-1957) was botanist on the Scotia Expedition. After working for Bruce after their return, he turned to geography, becoming Lecturer at Sheffield in 1907 and Reader at Manchester in 1920. He returned to Sheffield as Professor of Geography in 1931, retiring in 1945. In both World Wars, he served in Admiralty intelligence. Throughout, he continued his interest in the Arctic and Antarctic. He died in Sheffield in 1957.

Pirie (1878-1965) was the expedition’s medical officer, geologist and bacteriologist. On his return he was a medical practitioner in Edinburgh until 1913 when he joined the Colonial Service as a bacteriologist in Kenya. He was Deputy Director of the South African Institute for Medical Research from 1926 until 1941. In 1940 he gave the name Listeria (after Joseph Lister) to the bacterial genus. In 1948 he was living in Bournemouth on the south coast of England.

So, did Wilson not realise that the findings from the Scotia expedition would render his quest for Emperor penguin embryos unnecessary? Or did he judge the Emperor to be so different, in fact unrelated to the Adelie and Gentoo, that he thought the findings irrelevant? Was he even aware of the results from the Scotia expedition? Was he too busy with his work on the grouse disease inqjuiry and preparing for the Terra Nova expedition to study Waterston and Geddes’s findings between their publication in October 1909 and the departure of the Terra Nova in June 1910? I have been unable to find the answers to any of these questions from reading about Edward Wilson.

However, here’s where the politics of polar exploration kicks in. The Scotia expedition and its leader, Bruce, were regarded as the lowest forms of life by the power broker in British antarctic exploration, Sir Clement Markham, President of the Royal Geographical Society. All my reading indicates that Markham was rightly considered by later commentators a classic Monster. However, Markham’s personality is beside the point. The animus to Bruce was so great that I find it difficult to see Wilson raising any of the (excellent) results of that expedition in discussions over whether it was worthwhile to attempt the journey to Cape Crozier to collect the Emperor embryos with Markham in full control of the expedition and Scott, Wilson’s friend but Markham’s protégé.

From what I have read so far, I conclude that the collection of Emperor embryos was Wilson’s big ‘thing’ and had been his big ‘thing’ since his earlier discoveries on this species in the Discovery expedition of 1901-1904.

Geoge Seaver, in his book on Wilson, states that he gave three lectures to fellow expedition members and that ‘his own notes of them have been preserved but those taken by Scott and others are not without interest…In his second lecture he traced the descent of Penguins from the primitive lizard-bird, explaining their anatomy, and finding corroborative evidence in their primitive fossilized remains’. Those notes could well be worth examining anew to see what Wilson’s understanding was at that time.

Apsley Cherry-Garrard, Wilson’s protégé, who with Wilson and Bowers undertook that indescribable winter journey from Cape Evans to the rookery at Cape Crozier wrote in The Worst Journey in the World:
What is this venture? Why is the embryo of the Emperor penguin so important to Science? And why should three sane and common-sense explorers be sledging away on a winter's night to a Cape which has only been visited before in daylight, and then with very great difficulty?The Emperor is a bird which cannot fly, lives on fish and never steps on land even to breed. It lays its eggs on the bare ice during the winter and carries out the whole process of incubation on the sea-ice, resting the egg upon its feet, pressed closely to the lower abdomen. But it is because the Emperor is probably the most primitive bird in existence that the working out of his embryology is so important. The embryo shows remains of the development of an animal in former ages and former states; it recapitulates its former lives. The embryo of an Emperor may prove the missing link between birds and the reptiles from which birds have sprung*.
After the deaths of Scott, Wilson, Bowers, Oates and Edgar Evans on their return from the Pole, Cherry-Garrard obtained a series of embryos from Adélie Penguins at Cape Royde. He wrote:
It was always Wilson's idea that embryology was the next job of a vertebral zoologist down south. I have already explained that the penguin is an interesting link in the evolutionary chain, and the object of getting this embryo is to find out where the penguins come in. Whether or no they are more primitive than other nonflying birds, such as the apteryx, the ostrich, the rhea and the moa, which last is only just extinct, is an open question. But wingless birds are still hanging on to the promontories of the southern continents, where there is less rivalry than in the highly populated land areas of the north. It may be that penguins are descended from ancestors who lived in the northern hemisphere in a winged condition (even now you may sometimes see them try to fly), and that they have been driven towards the south. 
If penguins are primitive, it is rational to infer that the most primitive penguin is farthest south. These are the two Antarcticists, the Emperor and the Adélie. The latter appears to be the more numerous and successful of the two, and for this reason we are inclined to search among the Emperors as being among the most primitive penguins, if not the most primitive of birds now living: hence the Winter Journey. I was glad to get, in addition, this series of Adélie penguins' embryos, feeling somewhat like a giant who had wandered on to the wrong planet, and who was distinctly in the way of its true inhabitants.
So Cherry-Garrard in 1922 seems to be expressing a different reason for collecting embryos—that the most southern could be the most primitive penguins but not the most primitive bird—from Wilson in 1910. But the phrase if not the most primitive of birds now living could be taken to mean that it still might be shown that the Emperor is the most primitive bird. Alternatively, if not actually means even if not.  I tend to think it means the latter since otherwise he would be contradicting himself in these paragraphs.

Cherry-Garrard collected embryos from the Adélies during that period after the remaining members of the expedition found the bodies of the polar party, Scott, Wilson and Bowers. Surely Wilson in the many months they had together would have mentioned to Cherry-Gerrard whether Adéle embryos had been examined previously. That leads me to think that Wilson had not seen the report of the Scotia Expedition before embarking on Terra Nova. Original documents and notes on the contents of the libary taken by Scott and his party could well provide more information.

The story of penguin embryos does not end there…

----------------------
Waterston D, Geddes AC (1909) Report upon the anatomy and embryology of the penguins collected by the Scottish National Antarctic Expedition. Transactions of the Royal Society of Edinburgh 47 part 2, number 10, 223-244

Seaver, G (1933) Edward Wilson of the Antarctic. Naturalist and Friend. London: John Murray

*There is a difference in wording between the Pimlico edition 2003 (Vintage 2010) and that available online as a Project Gutenberg eBook; the latter appears to be from the original 1922 edition published by Constable in 1922.

‡Excellent photographs of the expedition are at:

Monday, 16 June 2014

Forest Elephants in the Republic of Congo. What Species Were We Observing?

Opportunities to see the animals of the central African rainforests do not come every day. So the privilege of being able to visit groups of lowland gorillas and observe the other mammals, birds, reptiles and amphibians in the Congo Basin is an experience of a lifetime. In the middle of May we were with a group of ten clients of Naturetrek in the camps in the Republic of Congo run by Wilderness Safaris, Ngaga and Lango, 340 miles from Brazzaville, both in or adjacent to the Odzala-Kokoua National Park.

Lango Camp (the word ‘camp’ should be in inverted commas) is situated with views from the raised deck of Lango bai. Watching the bai as animals turn up is a delight, especially in the early morning when large flocks of African Green Pigeons fly overhead and African Grey Parrots appear from the forest to eat mud churned up by the elephants and buffalo. And by elephants I mean Forest Elephants and by buffalo, Forest Buffalo. Later in the day, solitary Bushbuck appeared and, just after our arrival, a Sitatunga.

This video shows what we saw at Lango Camp.




Talking about Forest Elephants with our guides, Justine, Alon and Adam, and the differences between forest and savanna elephants I knew that over the last century there had been arguments to and fro as to whether the Forest Elephant was a different species from the African Elephant. All the more recent books seemed to repeat the view that there was only one species of Elephant in Africa. I was also vaguely aware that the Forest Buffalo was not considered to be a separate species and that, recently, the Bushbuck had been split by somebody into two species.

Because when I actually saw Forest Elephants for the first time in the flesh and could appreciate that morphologically they were very different from the elephants we had seen in other parts of Africa, I resolved to look up their status in more detail when we got back.

Behaviourally too the Forest Elephant is very different. The nocturnal shrieks and cries that kept us awake as elephants gathered further down the bai were very different from the silence or low grumblings of other elephants. My natural tendency as a ‘lumper’ to think of one species of elephant in Africa was being shaken to the core at 2.00 am.

To cut a long story short, I am now convinced by the evidence available that the Forest Elephant is a separate species, that named by Matschie in 1900 as Loxodonta cyclotis. But in reading the papers, I was struck by the strange reluctance of many to accept this conclusion. IUCN still lumps all the elephants in Africa as Loxodonta africana.

Leaving aside the morphological differences and questions of gene flow between Forest and Savanna or Bush Elephants for the moment, the arguments that have arisen in the past 15 years or so have centred on genetic differences in populations of elephants in Africa. Different results were obtained using mitochondrial DNA (mtDNA) compared to nuclear DNA (nDNA).

The use of nuclear DNA to determine the phylogeny of elephants has been championed by Alfred L Roca’s group at the University of Illinois at Urbana-Champaign. Their first work was published in 2001 and showed a clear distinction between Forest and Savanna elephants. However, the single-species-in-Africa view continued as more work using mitochondrial DNA showed a number of geographically based clades. Nevertheless, continuing work by Roca’s group on nuclear DNA demonstrated that Forest and Savanna elephants were different and that mitochondrial DNA does not provide information on which the phylogeny of these species can be determined. In short, mitochondrial DNA provides a historical record of only the maternal line and with the introgression of genes by early hybridisation between separating lines during speciation or by later hybridisation leading to some fertile offspring, the mitochondrial DNA may bear no relation to the nuclear DNA of the species as a whole. As one paper (Rohland, Reich, Mallick, Meyer, Green, Georgiadis, Roca & Hofreiter, 2010) puts it:
…mtDNA represents just a single locus in the genome and need not represent the true species phylogeny since a single gene tree can differ from the consensus species tree of the taxa in question. Generalizing about species relationships based on mtDNA alone is especially problematic for the Elephantidae because their core social groups (‘‘herds’’) are matrilocal, with females rarely, if ever, dispersing across groups. This results in mtDNA genealogies in both African and Asian elephants that exhibit deeper divergence and/or different phylogeographic patterns than the nuclear genome.
Further strengthening of the case for two species in Africa came from work comparing these two elephants with the Asian Elephant and the relatively recently extinct Woolly Mammoth and American Mastodon.  Rohland et al. (2010) reported (with my emphasis in bold characters):
We have used a combination of modern DNA sequencing and targeted PCR amplification to obtain a large data set for comparing American mastodon, woolly mammoth, Asian elephant, African savanna elephant, and African forest elephant. We unequivocally establish that the Asian elephant is the sister species to the woolly mammoth. A surprising finding from our study is that the divergence of African savanna and forest elephants—which some have argued to be two populations of the same species—is about as ancient as the divergence of Asian elephants and mammoths. Given their ancient divergence, we conclude that African savanna and forest elephants should be classified as two distinct species.
And then, on the two African species (with references deleted):
Our study also infers a strikingly deep population divergence time between forest and savanna elephant, supporting morphological and genetic studies that have classified forest and savanna elephants as distinct species. The finding of deep nuclear divergence is important in light of findings from mtDNA, which indicate that the F-haplogroup is shared between some forest and savanna elephants, implying a common maternal ancestor within the last half million years. The incongruent patterns between the nuclear genome and mtDNA (‘‘cytonuclear dissociation’’) have been hypothesized to be related to the matrilocal behavior of elephantids, whereby males disperse from core social groups (‘‘herds’’) but females do not. If forest elephant female herds experienced repeated waves of migration from dominant savanna bulls, displacing more and more of the nuclear gene pool in each wave, this could explain why today there are some savanna herds that have mtDNA that is characteristic of forest elephants but little or no trace of forest DNA in the nuclear genome. In the future, it may be possible to distinguish between models of a single ancient population split between forest and savanna elephants, or an even older split with longer drawn out gene flow, by applying methods like Isolation and Migration (IM) models to data sets including more individuals.

The problems inherent in using mitochondrial DNA have been stressed recently by Jerry Coyne in his blog, Why Evolution is True, in relation to the evolution of the Brown Bear and the Polar Bear in which conclusions drawn from mitochondrial DNA have been shown to confuse rather than illuminate. This is a screen grab from his blog:



This entry can be found at:
http://bit.ly/1lJEwmH

IUCN still persists in lumping all the elephants in Africa into one species. However, in a hard-hitting paragraph in the discussion of their paper, Ishida, Oleksyk, Georgiadis, David, Zhao, Stephens, Kolokotronis & Roca (2011) state the case clearly and why it is important for practical conservation:
“Mitochondrial essentialism” and the conservation of Africa's elephantsGiven that mtDNA haplotypes among elephants are an unreliable indicator of overall genetic similarity it is unfortunate that mtDNA alone continues to be used as a guide to elephant genealogical affinities. This “mitochondrial essentialism,” the continuing use of mtDNA to partition populations and species, among elephants where morphological and nuclear markers have established that mtDNA patterns may be inaccurate or misleading, might lead to adverse results for elephant conservation, as the following examples illustrate: If mtDNA data were used as the sole basis for elephant taxonomy and population structure, elephants in the Guinean forest block could be recommended for translocation to the deserts of Mali, on the grounds that their mtDNA similarity implies that they must be genetically similar. Likewise, relying on mtDNA to infer population structure would mean that savanna elephants from Tanzania could be moved west into the Congolian tropical forest, since forest and savanna elephants in these regions share similar F clade mtDNAs. Either of these translocations would be inappropriate, since even while carrying mtDNA from the same haplogroup, individuals in forest and savanna locations are very different in nuclear genotypes, belong to different species, and are thus unlikely to thrive when moved to the wrong habitats. Although the examples are extreme, it may be equally troublesome that mtDNA-based misinterpretations of African elephant taxonomy constitute an unacknowledged potential hindrance to their proper conservation by convincing conservation groups to “continue to treat African elephants as a single species”.
Although studies based solely on mitochondrial DNA appear to be useless in this and many other cases, there is a bonus as Roca and his colleagues have both pointed out and actually worked on: the use of both nuclear and mitochondrial genetic markers can more accurately determine the geographical source of poached ivory.

But now we come full circle. The Forest Elephant was described as a new species by Professor Dr (Georg Friedrich) Paul Matschie (1861-1926) in 1900. Unfortunately, Matschie, who somehow rose to be Director of the Berlin Museum in 1924, was treated as a joke by fellow professionals. An anti-Darwinian mystic, he described a new species or subspecies from pretty well every specimen that fell under his gaze. Mammalian taxonomy seems to have suffered mightily as a result of his activities. His antics and those of his protégé are described, unfortunately briefly, by Colin Groves and the late Peter Grubb in their book, Ungulate Taxonomy (Johns Hopkins University Press, 2011). The ultimate splitter caused a lumping backlash. (Groves and Grubb, incidentally were responsible for the morphological work that resurrected the two-species-in-Africa idea in 2000.) I have the suspicion that Matchie’s involvement in erecting Loxodonta cyclotis may have been one of the reasons why there was such opposition to the possibility of the existence of a separate Forest Elephant in the last century. So, sadly, it appears that Matschie, for once, was right. Maybe right for the wrong reasons but right.



For those wanting more information, these papers and the references therein contain the story as it stands at the moment.

Roca AL,  Georgiadis N,  Pecon-Slattery J, O’Brien SJ (2001) Genetic Evidence for Two Species of Elephant in Africa. Science 293, 1473-1477
Ishida Y, Oleksyk TK, Georgiadis NJ, David VA, Zhao K, Stephens RM, Koloktronis, S-O, Roca AL (2011) Reconciling Apparent Conflicts between Mitochondrial and Nuclear Phylogenies in African Elephants. PLoS ONE 6(6): e20642. doi:10.1371/journal.pone.0020642
Roca AL, Georgiadis N, O’Brien SJ (2004) Cytonuclear genomic dissociation in African elephant species. Nature Genetics 37 96-104
Ishida Y, Demeke Y, Van Coeverden de Groot PJ, Georgiadis NJ, Leggett KEA, Fox VE, Roca AL. Distinguishing Forest and Savanna African Elephants Using Short Nuclear DNA Sequences. Journal of Heredity 2011 610-616
Rohland N, Reich D, Mallick S, Meyer M, Green RE, Georgiadis NJ, Roca AL, Hofreiter M. (2010) Genomic DNA Sequences from Mastodon and Woolly Mammoth Reveal Deep Speciation of Forest and Savanna Elephants. PLoS Biol 8(12): e1000564. doi:10.1371/journal.pbio.1000564

Saturday, 7 June 2014

Sea Snakes: My Only Sighting

My earlier Post on the survival of  sea snakes at sea reminded me that I have only seen sea snakes in the wild once, and that was while gently walking from the restaurant at the Shangri La Tanjung Aru Resort, Kota Kinabalu in Sabah (North Borneo) in 1999. The snakes were crawling among the rocks below the concrete platform that forms the sea front. They were Laticauda colubrina, the banded sea snake. This site is mentioned in the Wikipedia article on this species as a place where they occasionally come ashore. According to that article, the males come ashore in the early evening and the females later.




I was very pleased to find the above photograph from Getty Images since it is by Sue Flood, a great photographer and a great person to travel with.