Tag Archives: Zoology

February 8, 1825 (a Tuesday)

Plate from Bates’ Contributions to an Insect Fauna of the Amazon Valley: Heliconiidae (1862) illustrating Batesian mimicry between Dismorphia species (top row, third row) and various Ithomiini (Nymphalidae) (second row, bottom row).

On this date, the English entomologist Henry Walter Bates was born. Bates became friends with Alfred Russel Wallace when the latter took a teaching post in the Leicester Collegiate School. Wallace was also a keen entomologist, and he had read the same kind of books as Bates had, and as Darwin, Huxley and no doubt many others had – Thomas Malthus on population, James Hutton and Charles Lyell on geology, Charles Darwin’s Voyage of the Beagle, and above all, the anonymous Vestiges of the Natural History of Creation, which put evolution into everyday discussion among literate folk. They also read William H. Edwards on his Amazon expedition, and this started them thinking that a visit to the region would be exciting, and might launch their careers. Bates accompanied Wallace on an expedition to the Amazon in 1848.

Whereas Wallace returned to England after four years in South America and then went on to Indonesia, Bates stayed in the Amazon for eleven years but continued to correspond with him, encouraging Wallace’s developing theories on organic evolution. Bates discovered that closely related species often were separated geographically by rivers, and later realized that this was evidence of geographical speciation. His 1862 study of color patterns in butterflies established what is now called Batesian mimicry, in which non-poisonous animals mimic the bright warning coloration of poisonous animals. Bates argued that this kind of mimicry could not be produced by Lamarckian use-inheritance and was clear evidence of selection. In his book The Naturalist on the River Amazons (1863), he wrote:

on these expanded membranes [i.e., butterfly wings] Nature writes, as on a tablet, the story of the modifications of species, so truly do all changes of the organisation register themselves thereon. Moreover, the same colour-patterns of the wings generally show, with great regularity, the degrees of blood-relationship of the species. As the laws of nature must be the same for all beings, the conclusions furnished by this group of insects must be applicable to the whole world.

Bates assumed the post of Assistant Secretary of the Royal Geographical Society in 1864 where he edited the society’s Transactions and organized expeditions. He was elected a Fellow of the Royal Society of London in 1881.

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February 3, 1790 (a Wednesday)

Illustration of fossil Iguanodon teeth with a modern iguana jaw from Mantell’s 1825 paper describing Iguanodon.

On this date, the British physician, geologist, and paleontologist Gideon Algernon Mantell was born. He discovered 4 of the 5 genera of dinosaurs known during his time.

Mantell’s life-long hobby was all-consuming. While walking with his wife in 1822, he discovered fossils that he identified as teeth. When he saw the connection with teeth of the present lizard, the iguana, in 1825, he named the animal the Iguanadon (“fossil teeth”). Subsequently, he made additional finds of fossil bones of other large animals which he described accurately: the Hylaeosaurus, Pelorosaurus, and Regnosaurus. His contemporary, paleontologist Sir Richard Owen, coined the word dinosaur (“terrible lizards”). Mantell’s books include Medals of Creation (1844).

January 31, 1910 (a Monday)

Ichthyostega

On this date, the Swedish geologist and paleontologist Gunnar Säve-Söderbergh was born. He took bachelor’s and licentiate’s degrees at Uppsala University in 1931 and 1933, respectively, and was appointed professor of historical geology at Uppsala in 1937.

In 1928, Säve-Söderbergh led a team that discovered extraordinarily fossiliferous beds in the upper Devonian of east Greenland. These 360-million-year-old rocks contained numerous fossils of bony fish and one set of particularly interesting remains. These latter fossils possessed a fish-like tail, ribs, and back, yet also had limbs with fingers and toes. This new species was dubbed Ichthyostega by Säve-Söderbergh in 1932 and was described in a series of papers by Erik Jarvik. It is widely featured in the scientific literature as the first “four-legged fish”. Although Ichthyostega may not be the ancestor of today’s terrestrial vertebrates, it no doubt is a transitional form.

The hind limb of Ichthyostega.

Ichthyostega‘s combination of fish and amphibian characters led to speculation about how the origin of tetrapods and the invasion of land by vertebrates could be related. One hypothesis, formulated by Joseph Barrell and later revised by Alfred Romer, held that one group of fish, such as Ichthyostega, adapted to more terrestrial environments due to the drying of Devonian ponds. Recent discoveries have changed this conception entirely.

Säve-Söderbergh was made an honorary doctor at Uppsala in 1942 and was elected a member of the Royal Swedish Academy of Sciences in 1948. Unfortunately, tuberculosis put an untimely end to his career. He died in 1948 at Solbacken, a sanatorium in Dalarna, Sweden.

January 18, 1823 (a Saturday)

William Buckland

William Buckland

William Buckland, Professor of Geology at Oxford University and an ordained priest in the Church of England, had been contacted by the Talbot family of Penrice Castle on the Gower Peninsula in South Wales, England, who had reported finding “bones of elephants” on 27 December 1822. Descending into Paviland Cave (or Goat’s Hole Cave) on today’s date, Buckland discovered one of the best-known prehistoric burials in Britain – the notoriously misnamed “Red Lady of Paviland.”

In the field, Buckland had identified the skeleton as male, suggesting that the bones were those of a Customs Officer murdered by smugglers. By the time of publication later that year, however, the gender and age of the skeleton had changed with a new and better, but still erroneous, story.

Found at Paviland

Buckland, a devout Christian, believed no human remains could have been older than the Biblical Great Flood, and thus wildly underestimated its true age, believing the remains to date back to the Roman era. He believed the skeleton was female in large part because it was discovered with decorative items, including perforated seashell necklaces and ivory jewelry. These decorative items combined with the skeleton’s red dye caused Buckland to mistakenly speculate that the remains belonged to a Roman prostitute or witch. He later wrote in his book Reliquiae Diluvianae (Evidence of the Flood):

[I found the skeleton] enveloped by a coating of a kind of ruddle…which stained the earth, and in some parts extended itself to the distance of about half an inch [12mm] around the surface of the bones… Close to that part of the thigh bone where the pocket is usually worn surrounded also by ruddle [were] about two handfuls of the Nerita littoralis [periwinkle shells]. At another part of the skeleton, viz in contact with the ribs [were] forty or fifty fragments of ivory rods…[also]…some small fragments of rings made of the same ivory and found with the rods… Both rods and rings, as well as the Nerite shells, were stained superficially with red, and lay in the same red substance that enveloped the bones.

The “lady” has since been identified as a man, probably no older than 21, who lived about 26,000 years ago (26,350 ± 550 BP). It remains the first human fossil found and identified soon after its discovery and the oldest anatomically modern human remains found in the United Kingdom.

Buckland is also famous for being the first person to discover, name, and scientifically describe a fossilized creature that came to be recognized as what Richard Owen was to call a dinosaur. Buckland’s name for the animal was Megalosaurus, Greek for “great lizard”. Though he was not the first person to find a Megalosaurus bone (Robert Plot discovered a fossilized femur of one as far back as 1676), Buckland was the first to realize that these fossils belonged to an unknown class of huge reptiles. According to his calculations, the animal must have exceeded forty feet in length and weighed as much as a large elephant. Some people think his 1824 paper to the Geological Society of London (“Notice on the Megalosaurus or Great Fossil Lizard of Stonesfield”) inaugurated the modern study of dinosaurs.

Buckland’s interest in dinosaur remains included more than bones. He also carried out a large amount of research into fossilized dinosaur feces. At a meeting of the Geological Society of London on 6 February 1829, Buckland described them and introduced the term coprolites (from the Greek words “kopros”, meaning dung, and “lithos”, meaning stone). His paper, “On the Discovery of Coprolites, or Fossil Faeces, in the Lias at Lyme Regis”, states that they have “undergone no process of rolling, but retain their natural form, as if they had fallen from the animal into soft mud, and there been preserved,” later comparing them to “oblong pebbles or kidney-potatoes.”

William Buckland Fossil Faeces (Coprolites).

William Buckland Fossil Faeces (Coprolites).

Interestingly, Buckland was very eccentric. He caused such a stir with his explicit lectures on the mating habits of reptiles that The Times of London felt he should restrain his enthusiasm “in the presence of ladies”. He always wore his academic gown when out digging for fossils. The hallway of his Oxford home was lined with the skulls of animals. Monkeys, a bear (in a mortarboard) and a hyena, amongst other animals, had the run of the house (the hyena ate the family’s guinea pig).

But strangest of all was Buckland’s diet. He was a committed zoophagist — an eater of animals. All animals. In Buckland’s opinion, the Creator had placed the creatures of the world at Man’s service, to feed and clothe him and to be his companions, and it was Man’s duty to eat the rich bounty of foods provided by the Almighty for his sustenance. And eat them he did — from elephant trunk soup, panther chops, horse tongue, porpoise head, crispy mice in batter, kangaroo ham, and eland steaks to accidentally grilled giraffe (there had been a fire at the London Zoo). He found the taste of mole to be the worst, until he tasted bluebottles.

Once, while touring a church, the local vicar showed him “martyr’s blood” dripping from the rafters — Buckland dropped to his knees and began to lap at the miraculous liquid, which was, he announced between laps, bats’ urine. On a visit to Nuneham House, he was shown a silver casket holding what was reputed to be the heart of King Louis XIV of France. Before anyone could stop him, Buckland announced, “I have eaten many strange things, but have never eaten the heart of a king before,” before snatching it up and swallowing it.

Buckland’s eccentricities earned him a famous description by Charles Darwin, who wrote: “though very good-humoured and good-natured [he] seemed to me a vulgar and almost coarse man. He was incited more by a craving for notoriety, which sometimes made him act like a buffoon, than by a love of science.”

References:

January 16, 1932 (a Saturday)

Dian Fossey in November 1985; photograph by Yann Arthus-Bertrand.

On this date, Dian Fossey, an American primatologist who for years made a daily study of the mountain forest gorillas of Rwanda, central Africa, was born in San Francisco, California. Her strong interest in animals led her to enter college as a pre-veterinary student. However, she soon switched to occupational therapy and obtained her degree from San Jose State College in 1954.

But Fossey dreamed of seeing more of the world and its abundant wildlife. Therefore, in 1963, she took out a bank loan and began planning her first trip to Africa. Her trip included visits to Kenya, Tanzania (then Tanganyika), Congo (then Zaire), and Zimbabwe (then Rhodesia).

An experience that Fossey would later point to as a pivotal moment in her life was her visit to Olduvai Gorge in Tanzania. There, she met Dr. Louis Leakey, who encouraged her initial interest in gorillas.

I believe it was at this time the seed was planted in my head, even if unconsciously, that I would someday return to Africa to study the gorillas of the mountains.

Upon arriving home in Kentucky Fossey returned to work as an occupational therapist to repay the loan she had taken to pay for her trip to Africa … all the while dreaming of the day she would return.

There was no way that I could explain to dogs, friends, or parents my compelling need to return to Africa to launch a long-term study of the gorillas. Some may call it destiny and others may call it dismaying. I call the sudden turn of events in my life fortuitous.

In December 1966, Fossey was again on her way to Africa. She arrived in Nairobi, acquired the necessary provisions, and set off for the Congo. On the way, she made a stop to visit the Gombe Stream Research Centre to meet Jane Goodall and observe her research methods with chimpanzees. Eventually, Fossey moved her focus to Volcanoes National Park on the Rwandan side of the Virungas. On 24 Sept. 1967, she established and then directed the Karisoke™ Research Centre in Rwanda.

Little did I know then that by setting up two small tents in the wilderness of the Virungas I had launched the beginnings of what was to become an internationally renowned research station eventually to be utilized by students and scientists from many countries.

Dian Fossey with two juvenile gorillas in Rwanda sometime between 1968 and 1970 (photo credit: National Geographic photographer Bob Campbell).

Living a solitary life for many years, Fossey observed the gorillas’ habits and gradually gained their acceptance. In 1970, she enrolled in the department of animal behavior at Darwin College, Cambridge, under Dr. Robert Hinde, who had also been Jane Goodall’s supervisor. She traveled between Cambridge and Africa until 1974, when she completed her Ph.D. Armed with the degree, she now felt that she could be taken more seriously. This also enhanced her ability to continue her work, command respect, and most importantly, secure more funding.

In 1980, Fossey moved to Ithaca, New York, as a visiting associate professor at Cornell University. She used the time away from Karisoke™ to focus on the manuscript for her book, Gorillas in the Mist. Published in 1983, the book is an account of her years in the rainforest with the mountain gorillas. Most importantly, it underscores the need for concerted conservation efforts.  Praised by Nikolaas Tinbergen, the Dutch ethologist and ornithologist who won the 1973 Nobel Prize in Physiology or Medicine, the book was well received and remains popular to this day.

Fossey was brutally murdered in 1985, her attacker or attackers splitting her skull with a machete, the type commonly used by poachers. She was found in the bedroom of her cabin at Karisoke™ and had apparently tried to load her pistol during the attack. To this day her killer or killers have not been found.

There are de-classified diplomatic cables from Fossey’s time which indicate outright collusion between Melvin Payne, then President of the National Geographic Society, Secretary of State Cyrus Vance, and Rwandan Ambassador Frank Crigler to remove Fossey from Rwanda. A smear campaign was underway to discredit her so that money-making “conservation” schemes could be implemented by the African Wildlife Fund (AWLF) and the colonialist Mountain Gorilla Project.

Also, diplomatic cables and writing from that time indicate that higher ups realized Protais Zigiranyirazo, governor of Ruhengeri Province in Rwanda when Fossey worked there, was a likely suspect in Fossey’s murder. He was involved in illegal trading in endangered species and gold smuggling out of Congo, and there is much additional evidence in the historical record that Fossey was about to expose him when she was killed. Zigiranyirazo is now living in Abidjan, the capital of Ivory Coast.

Fossey was laid to rest in the graveyard behind her cabin, among her gorilla friends. The last entry in her diary read:

When you realize the value of all life, you dwell less on what is past and concentrate on the preservation of the future.

As Fossey’s legacy is reflected upon, it is clear that she significantly contributed both to science and conservation. Primatology benefited from her ability to endure many years of fieldwork and in turn reveal new knowledge concerning gorilla behavior, while primate conservation gained great momentum from the combination of Fossey’s bravery and ability to attract and hold the public’s attention.

References:

January 1, 1758 (a Sunday)

Cover of the tenth edition of Linnaeus's Systema Naturae (1758).

On this date, the tenth edition of Linnaeus’s Systema Naturae was published, which is considered the starting point of zoological nomenclature; the oldest scientific names of animals accepted as valid today can be traced to this edition. Here, Linnaeus introduced the modern practice of using binomials for animal species, something he had done for plant species in the 1753 publication of Species Plantarum. Interestingly, in the first edition of Systema Naturae, the whales were erroneously classified as fishes; in the 10th edition, the whales were moved to the mammals.

December 30, 1818 (a Wednesday)

Scales of Justice

On this date,  Samuel Latham Mitchill appeared in the packed chambers of the Mayor’s Court in New York City Hall as the star witness in the case of James Maurice v. Samuel Judd, a dispute arising under a New York State statute that obliged purveyors of “fish oils” to ensure that their casks had been inspected.

The facts of the case today seem boring. On March 31, 1818, the New York State Legislature passed a law to ensure the quality of fish oils, which were widely used in the tanning and preservation of leather at the time. The law called for a corps of inspectors to “seek out any parcels of fish oil” and to certify the amount of water, sediment, and pure oil each cask contained. It also stipulated that a fine of twenty-five dollars per cask be levied on any buyer of uninspected fish oil. Three months later, a certain Mr. Samuel Judd, owner of the New-York Spermaceti Oil & Candle Factory at 52 Broadway, bought three casks of “fish oil” that had not been “gauged, inspected, and branded, according to law.” Judd claimed he didn’t have to pay the required fine because he had purchased spermaceti, or whale oil, so James Maurice, a city inspector of fish oil, began proceedings to collect the fine.

Judd’s view reflected an intellectual quandary of his time: If a whale is a fish, then why is its tail horizontal rather than vertical? Why do whales not have scales? Why are whales warm-blooded, not cold-blooded like fish? Why do whales breathe air (that whales could drown was a proven fact by then), and give birth (and nurse their young with milk) rather than lay eggs? Why were whales so much smarter than lesser fish? (Apart from the challenge of their size was the challenge of their brains — whaling is hunting, not mere fishing.) And, perhaps most importantly, why did the insides of whales — which were known in the most minute detail as a simple commercial matter — resemble not the lesser fishes but rather cows and pigs?

A New York whaleman’s drawing of a sperm whale, ca. 1810.

However, to many zoologists of the time (but not all), the inside of a whale would have been totally irrelevant.  [Interestingly, Linnaeus himself had said whales were fish in the 9th edition of the Systema Naturae, but formally separated them in the 10th edition, published only two years later in 1758.]  In terms of what today is known as taxonomy, shape and environment were the categorical bases for grouping animals, not internal anatomy. Whales looked like fish (tails and blowholes notwithstanding) and lived where fish lived. The 1817 edition of a leading English dictionary defined fish simply as “an animal that lived exclusively in water”. Even Genesis clearly delineated creation by environment: “fish of the sea” (so, as a matter of elementary Judeo-Christian theology, oysters and crabs are “fish”), “fowl of the air” (bats?), and “every creeping thing that creepeth upon the earth.” Again, whales don’t creepeth upon the earth, so the notion that they are “animals” was fundamentally un-Christian and even bordered on blasphemy. Therefore, whales are fish.

Image of a whale being flensed, from a book called Medieval Life and People.  It has a fish face. It has a fish backbone and tail (bending from side to side rather than flexing up and down). But it has breasts.

Image of a whale being flensed, from a book called Medieval Life and People. It has a fish face. It has a fish backbone and tail (bending from side to side rather than flexing up and down). But it has breasts.

Nevertheless, by 1818 zoologists had generally conceded that their field was far from complete and that debate and dissent about proper taxonomic classification was not only permissible but inevitable — especially as new species of just about everything kept being discovered. Moreover, the leading naturalists — particularly Samuel Latham Mitchill, a retired politician who also happened to be the preeminent authority on the fishes of New York and the founder of what would become the New York Academy of Sciences — aimed to convert taxonomy to a science of dissection: that species should be grouped together by how they looked on the inside rather than on the outside. Mitchill presented the Linnaean argument from anatomy: whales breathe air and have lungs, not gills; they have four-chambered hearts, like horses but unlike fish; their fins contain bones that are exact analogs of the hands and arms of apes and people; they even have eyelids that move. He famously remarked that “a whale is no more a fish than a man.”

Yet William Sampson, the lead prosecutor, challenged Mitchill at every turn, using arguments that have echoes in recent debates about Darwinian evolution. Was it not true, Sampson asked, that there was wide disagreement among scholars as to exactly how various animals should be classified? And what were common folk to make of the unlikely associations Linnaean taxonomy called upon them to make? Quoting Sampson:

Now, is not man strangely mated or matched when the whale and the porpoise are his second cousins, and the monkey and the bat his germans [close relations]? Other gentlemen may choose their company, [but] I am determined to cut the connection.

So what happened? After some wrangling about whether statutory interpretation should even be a question left to the lay jurors of a municipal trial court (a debate we sometimes have to this day), the judge charged the jury which, after only 15 minutes of deliberation, announced a verdict for the plaintiff.  [However, within a month, the New York State Legislature essentially overturned the verdict by exempting whale oil from inspection — in the eyes of the law, the whale would no longer count as a fish.]

More than a century before Scopes, science was put on trial, and was convicted.

References:

  • D. Graham Burnett, Trying Leviathan: The Nineteenth Century New York Court Case that Put the Whale on Trial and Challenged the Order of Nature (Princeton University Press, 2007).
  • Eric Jay Dolin, Leviathan: The History of Whaling in America (W.W. Norton, 2007) pp. 384-385.

December 28, 1894 (a Friday)

Alfred Sherwood Romer

Alfred Sherwood Romer

On this date, the American vertebrate paleontologist and comparative anatomist Alfred Sherwood Romer was born. The Society of Vertebrate Paleontology, which Romer helped establish, says that he “was the leading contributor to the discipline of vertebrate paleontology throughout the twentieth century. . . Romer’s major contributions were in the areas of the ancestry of vertebrates, Paleozoic tetrapods, and the antecedents of mammals.” Perhaps Romer’s most notable gift to scientific posterity were his three seminal works: Osteology of the Reptiles (1956), Vertebrate Paleontology (1966), and The Vertebrate Body (1977) – immortal tomes which still adorn the shelves of any self-respecting student of vertebrate paleontology and evolution.

December 23, 1810 (a Sunday)

Edward Blyth

On this date, the English zoologist and chemist Edward Blyth was born in London. Although he was considered one of the leading zoologists in India, and a prominent figure overall in his field, he is best known for his early recognition of some of the principles of natural selection. In three articles on variation published in The Magazine of Natural History between 1835 and 1837, he discussed the effects of artificial selection and described the process in nature (later called natural selection) as restoring organisms in the wild to their archetype (rather than forming new species). Also, he never actually used the term “natural selection”.

Blyth believed that natural selection only preserves a constant and unchangeable type or essence of created form, by eliminating extreme variations or unfit individuals that deviate too far from this essence. Ernst Meyer wrote that:

Blyth’s theory was clearly one of elimination rather than selection. His principal concern is the maintenance of the perfection of the type. Blyth’s thinking is decidedly that of a natural theologian…

In fact, according to Stephen Jay Gould, natural selection was a common idea (but not a term) among biologists of the time, as part of the argument for created permanency of species. It was seen as eliminating the unfit, while some other cause created well fitted species. Blyth considered that species had “invariable distinctions” establishing their integrity, and therefore could not accept the formation of new species because if it occurred, “we should seek in vain for those constant and invariable distinctions which are found to obtain”. Blyth did not see the ramifications of the principle (nor did anyone else), and did little to develop his thoughts any further.

In contrast, Darwin introduced the idea that natural selection was creative in giving direction to a process of evolutionary change in which small hereditary changes accumulate. He did not read Blyth until after formulating his own theory.

Blyth remained a valued correspondent of Darwin’s after his formal publication of evolution by natural selection, and remained a strong friend of Darwin. Blyth was one of the first to embrace Darwinism, and was a vocal supporter for the remainder of his years.

Interestingly, Blyth’s writings had a major influence on Charles Darwin. There can be no doubt of Darwin’s regard for Edward Blyth – in the first chapter of The Origin of Species he wrote:

…Mr Blyth, whose opinion, from his large and varied stores of knowledge, I should value more than that of almost any one…

References:

    • de Beer, Gavin. Charles Darwin: Evolution by Natural Selection. (London: Thomas Nelson & Sons, 1963) p. 102.
    • Gould, Stephen Jay. The Structure of Evolutionary Theory. (Cambridge, Massachusetts: Harvard University Press, 2002) pp. 137–141.
    • Mayr, Ernst. The Growth of Biological Thought. (Cambridge, Massachusetts: Harvard University Press, 1984) p. 489.

December 22, 1938 (a Thursday)

Preserved specimen of Latimeria chalumnae in the Natural History Museum in Vienna, Austria.

Preserved specimen of Latimeria chalumnae in the Natural History Museum in Vienna, Austria.


On this date, a coelacanth (Latimeria chalumnae) was caught at the mouth of the Chalumna River on the east coast of South Africa. The fish was caught in a shark gill net by Captain Goosen and his crew, who had no idea of the significance of their find. They thought the fish was bizarre enough to alert the local museum in the small South African town of East London.

The director of the East London Museum at the time was Miss Marjorie Courtney-Latimer. She alerted the prominent south African ichthyologist Dr J.L.B. Smith to this amazing discovery. This modern coelacanth was eventually named in honor of Miss Courtney-Latimer.

This coelacanth specimen led to the discovery of the first documented population, off the Comoros Islands, between Africa and Madagascar. For sixty years this was presumed to be the only coelacanth population in existence. However, on July 30, 1998, a coelacanth was caught in a deep-water shark net by local fishers off the volcanic island of Manado Tua in northern Sulawesi, Indonesia, about 10,000 km east of the Western Indian Ocean coelacanth population. In 1999 the Sulawesi coelacanth was described as a new species, Latimeria menadoensis, by Pouyaud, Wirjoatmodjo, Rachmatika, Tjakrawidjaja, Hadiaty and Hadie.

In 1836, the eminent naturalist Louis Agassiz described the first fossil coelocanth. Since then, fossils of some 125 species have been discovered, dating back over 360 million years, with a peak in abundance about 240 million years ago. Before 1938, coelacanths were thought to have become extinct approximately 66 million years ago, when they disappeared from the fossil record, so the discovery of a living coelacanth was very significant.

But why are there no coelacanth fossils since the days of the dinosaurs? The explanation seems to be that the coelacanths from the fossil record lived in environments favoring fossilization, whereas modern coelacanths, both in the Comoros and Sulawesi, are found in environments that do not favor fossil formation. They inhabit caves and overhangs in nearly vertical marine reefs, at about 200 meters depth, off newly formed volcanic islands.

One of the most distinctive features of the coelacanth is that, along with all six living species of lungfishes but unlike all other fishes, it has paired “lobed fins”. The fins of such “lobe-finned fishes” project from the body on stalks rather than attaching directly to the body. The stalks that support the fins contain the same basic bones as the arms and legs of terrestrial four-limbed animals (tetrapods). Coelacanths even move their paired fins much like land animals move their limbs: The right pectoral fin moves in conjunction with the left pelvic fin, for example. And their movement is extremely dexterous; they scull the water like oars and can rotate through 180 degrees.

In fact, at the time of its discovery in 1938, the coelacanths were thought to be the ancestors of the tetrapods. Although it is now thought that the lungfishes are the closest living relative of tetrapods, the coelacanths may still provide answers to some very interesting evolutionary questions.

Other interesting features of the coelacanths include an intracranial joint and a rostral organ, not known in any other living fish.

References:

  • Samantha Weinberg. A Fish Caught in Time: The Search for the Coelacanth (Harper Perennial, 2001).

December 22, 1956 (a Saturday)

Colo the gorilla (24 Aug 2009)

On this date, a gorilla was born in captivity for the first time in history. Born at the Columbus Zoo in Ohio and named Colo (a combination of Columbus and Ohio), the western lowland gorilla weighed four pounds. She was the daughter of Millie and Mac, two gorillas captured in French Cameroon, Africa, who were brought to the Columbus Zoo in 1951. For decades after people had first tried to keep gorillas in captivity, any gorilla’s path from the forest to the zoo was soaked in blood. The animals had to be captured in the wild when they were young — before they grew too big and powerful to handle. Hunters would first have to kill the baby’s parents and sometimes its entire family.

She almost didn’t make it,” says Jeffrey Lyttle, author of Gorillas In Our Midst, a book about the Columbus Zoo gorillas.

“At the time, the zookeepers knew that Colo’s [mother] was pregnant, but nobody knew the gestation period of a gorilla,” Lyttle recalls. “They thought it was nine months, like humans, but it turns out it is closer to eight and a half months. So they weren’t expecting the birth. A vet named Warren Thomas was making his morning rounds when he discovered Colo, in her amniotic sack, lying on the concrete floor of her mother’s cage. He reached in, tore open the sack, and began giving Colo mouth-to-mouth resuscitation.”

Luckily, the little gorilla lived. “It was huge national news,” says Lyttle. But zookeepers believed that Colo’s mother wasn’t up to the task of raising her baby. They were probably right, since many captive gorillas never had a chance to learn parenting skills from their own parents in the wild. “So Columbus built a special nursery for her,” Lyttle explains. “Zoo visitation went through the roof. They would dress Colo up for the holidays — put her in an Easter bonnet and fancy dresses. Some people say she still likes to wear her food dish as a hat because she spent so much of her infancy wearing hats.”

Colo is also the oldest living gorilla in captivity, following the death of 55 year old Jenny in September 2008.

December 15, 1869 (a Wednesday)

Joseph Barrell

Joseph Barrell

On this date, the American geologist Joseph Barrell was born. He was professor of structural geology at Yale University from 1908 until his death in 1919.

Barrell proposed that sedimentary rocks were produced not only by marine sedimentation but also by the action of rivers, winds, and ice (continental sedimentation).

He also proposed (1916) that the bright red color of many Devonian rocks meant that the rocks had been baked dry, like bricks, in arid conditions. [Barrell had been only half right; red rocks do sometimes form in droughts, but they form in moist tropical soils as well.]

Barrell, and subsequently the American paleontologist Alfred Sherwood Romer, speculated that droughts had caused lungfish to evolve into air-breathing land vertebrates, including tetrapods. According to this hypothesis, as the ponds dried, the fish had to adapt to life on land and so evolved features that enabled them to hop from pond to pond. [However, evidence discovered more recently suggests that the fish-to-tetrapod transition likely happened not in creatures that were adapting to land but in creatures living in water. In fact, everything special about tetrapods – limbs, digits, ribs, neck, and so on – might well have evolved in water, not on land.]

At a meeting of the Geological Society of America held in Albany, New York, in 1916 Barrell presented a paper on “Rhythms and the measurement of geologic time” that was later published in full in the Society’s Bulletin in 1917. The article became an instant classic in geology. Barrell argued that geological processes vary in intensity in a cyclical rather than a uniform fashion. Thus, current rates of geological change could not, as uniformitarians claim, be a reliable guide to the past. He suggested that the new radiometric dates should be used to interpret the sedimentological record. Thus, he accepted an age for the Earth of a few billion years at a time when many geologists still preferred an age of 100 million years.

Nature vibrates with rhythms, climatic and diastrophic [tectonic], those finding stratigraphic expression ranging in period from the rapid oscillation of surface waters, recorded in ripple-mark, to those long-deferred stirrings of the deep imprisoned titans which have divided earth history into periods and eras. The flight of time is measured by the weaving of composite rhythms- day and night, calm and storm, summer and winter, birth and death such as these are sensed in the brief life of man. But the career of the earth recedes into a remoteness against which these lesser cycles are as unavailing for the measurement of that abyss of time as would be for human history the beating of an insect’s wing. We must seek out, then, the nature of those longer rhythms whose very existence was unknown until man by the light of science sought to understand the earth. The larger of these must be measured in terms of the smaller, and the smaller must be measured in terms of years. Sedimentation is controlled by them, and the stratigraphic series constitutes a record, written on tablets of stone, of these lesser and greater waves of change which have pulsed thru geologic time. [“Rhythms and the Measurements of Geologic Time”, Bulletin of the Geological Society of America (1917) 28: 746]

Although Barrell’s concerns were seemingly diverse, they were actually variations on a common theme: the effects of physical agents on the evolution of the Earth and its inhabitants. Thus, “The Origin of the Earth” (1916), a lecture delivered to Yale’s Sigma Xi Society, discussed the conditions required for the genesis of the solar system and the development of the Earth; Barrell’s papers on sedimentology always related sedimentological processes to the larger problems of historical geology, as did his treatments of structural geology; he maintained that biological evolution was the result of physical and chemical agents, in that these are the factors determining the environment of organisms.

References:

  • Joseph Barrell, “Rhythms and the Measurements of Geologic TimeGeol. Soc. America Bull. (1917) 28: 745-904.
  • Patrick Wyse Jackson, The Chronologers’ Quest: The Search for the Age of the Earth (Cambridge, UK: Cambridge University Press, 2006) 195-6.

Look at the evidence!*

*Thanks to John M. Lynch at Stranger Fruit for bringing this to my attention.