Earliest Sirenians, Prorastomus and Protosiren. Timeline of Sirenian Evolution and Extinctions. Images of the four extant manatee and dugong, and the extinct Steller's Seacow.
Astonishing photographic evidence of similarities between modern sea cows and elephants. Including photographs with celebrity LeVar Burton from Reading Rainbow.
Up close and personal with LeVar Burton and Manatees video. Photographs of Toenails on Manatee, and discussing diet, eating habits and lifestyle of Sea Cows.
All images illustrated by Sharon Mooney, available for download and public distribution for educational purposes.
A PARAGRAPH ON SEA COW EVOLUTION BY CHARLES DARWIN FOLLOWED BY A RECENT DISCOVERY OF AN ANCIENT SEA COW FOSSIL WITH HIND LIMBS
"The Sirenia [which includes the sea cow / manatee - E.T.B.] form a very distinct group of mammals, and one of the most remarkable peculiarities in the existing dugong and lamentin is the entire absence of hind limbs without even a rudiment being left; but the extinct Halitherium had, according to Professor Flower, an ossified thighbone "articulated to a well-defined acetabulum in the pelvis..."
-- Charles Darwin, The Origin of Species, chapter XI "On the Geological Succession of Organic Beings," "On the Affinities of Extinct Species to each other, and to Living Forms"
Legged Sea Cow Fossil Found in Jamaica
By Hillary Mayell
for National Geographic News
October 10, 2001
The nearly complete skeleton of an ancient aquatic mammal with legs has been unearthed in Jamaica. The 50-million-year old skeleton is one of the best examples so far of the evolution from a land animal to an aquatic animal, said Daryl Domning, a paleontologist at Howard University in Washington, D.C., who reported the discovery.
The skeleton found in Seven Rivers, Jamaica, is a new genus and species of the order Sirenia, which encompasses the ancestors of modern-day manatees and dugongs. Commonly known as sea cows, sirenians are plant-eating mammals that spend their entire lives in water. They started out as land animals, however. This new find fills a significant gap in the fossil record, helping scientists complete the picture of how land animals evolved to sea creatures. "This is the most primitive fossil found so far," said Domning. "We've found others with legs that couldn't support the animal's body weight. But this is the first whole skeleton with legs that could support the animal's body weight out of water, yet has clear adaptations for aquatic life. "We essentially have every stage now," he added, "from a terrestrial animal to one that is fully aquatic."
Domning's study, for which the National Geographic Society funded the field work, appears in the October 11 issue of Nature.
Read the entire article.
EMAIL EXCHANGE WITH PROFESSOR DARYL P. DOMNING, AUTHOR OF SIRENIAN EVOLUTION IN THE NORTH PACIFIC OCEAN
Dear Professor Domning,
I am currently seeking to collect pictures portraying the known species of Sirenians and their evolution. You mentioned in your National Geo. article that there are extinct species of Sirenians with rear legs that were too small to support them. Where might I find such pictures on the web or in the literature?
I have already collected pictures of atavistic hind legs on modern day whales, and pictures of hind leg buds on cetacea fetuses. I am planning to collect photos of Sirenia as well, for the purpose of sharing them with creationists.
Sincerely, Edward T. Babinski
PROFESSOR DOMNING'S REPLY
Dear Mr. Babinski,
Unfortunately, no one has put much effort into drawing accurate pictures of most of the extinct sirenians, mainly because all the ones from about the end of the Eocene onward looked outwardly not much different from the modern ones, especially as regards hind limbs. Protosiren (Middle Eocene) still had substantial though weak hindlimbs; ones like Eosiren (Late Eocene) probably had vestigial external hindlimbs; but after that there was probably nothing else visible on the outside -- only bony vestiges inside the body outline.
What you can find are illustrations of the fossil bones themselves; key references are given in my article in Reports of the NCSE, vol. 21, no. 5-6, 2002. I hope this helps -- good luck with the creationists. What have they been saying about sirenians?
LIFE CHANGING TELEVISION
by Sharon Mooney
In the early part of 2000, I developed a strong interest in the Evolution-Creation debate. The evidence had always been available, for instance in the National Geographic magazine which my parents had subscribed to all their life, and on educational television stations like PBS, Discovery and The Learning Channel, but making the error that most young people do, I never paid a lot of attention to the information that was available to me.
I began paying closer attention to the documentaries on the evolution-creation debate not so long ago, and was amazed by what I soon learned. The information is not new, but my attention span was. PBS broadcasted "Evolution, The Triumph of an Idea" in 2001, and upon seeing their presentation of land mammal to sea mammal, and all the causes scientists have for establishing a relationship between the two, amazed me. In November 2001, National Geographic magazine released "The Evolution of Whales", co-written by Professor Hans Thewissen (a world renown Paleontologist), a real life, modern day "Alan Grant" (Jurassic Park), as I tell people. The article contained images which appeared to indicate remains of hind limbs still exist in some whales.
"Today's sperm whale has vestigial hind limbs."
Based on an image found on Page 71, National Geographic MagazineNovember 2001, "The Evolution of Whales"
I took this information at face value, and simply accepted it as fact, without ever double checking if they had concrete empirical evidence such as photographs. This lead to later conflicts with Fundamentalist Creationists, who claimed there are no photographs. I faithfully believed that this Professor "Hans Thewissen" who co-wrote the article, would not lie. I believed National Geographic must be telling the truth. I had developed a fond trust of National Geographic magazine, since childhood. My parents were Creationists, but they had always subscribed to National Geographic, and encouraged my siblings and myself to read the magazines and books. We had a healthy respect for the National Geographic Society. I still appreciate the assistance they gave our family in matters of science. For instance, when we noticed a strange and beautiful woodpecker that showed up in our backyard. My mother wrote National Geographic, questioning which species of Woodpecker it is, explaining to them the location we lived at, and the general environment. A researcher from National Geographic replied, defining the exact species of woodpecker, explaining it's rarity -- we were lucky to have had one turn up in our backyard, it's diet, it's preferred habitat, and mating rituals. Later, as I was picking butterbeans (we lived on a farm) I noticed an odd species of lady-bug. This unusual insect was at times a peculiar dull shade of off colored orange-brown -- it was chameleonic, and would change colors -- including turning into sparkling gold, just like a drop of gold reflecting the sunlight -- too beautiful to believe it was real! I dubbed it the "Gold bug". I kept seeing this particular type of ladybug in our garden. I had to know more about this fascinating insect. I wrote National Geographic and they replied with the exact species and all pertinent information. I never had cause to question their authority on matters of animal biology.
After reading numerous claims that no photographs or evidence exists for hind limbs on whales, I began a search for those photographs. I believed photos *must* exist if scientists like this famous Professor Hans Thewissen would say "Vestigial hind limbs exist". The day I went searching, I did not find any photographs, but I did find an article written by a man, by the name of Edward T. Babinski (holding a Bachelor of Science in Biology) posted on EvC Forum."Does evidence of transitional forms exist ? (Hominid and other)" and I contacted him, inquiring on photographs.
"Ed" Babinski (as I've come to know him in the past couple years) went about the task of tracking down the actual photographs, and combining them with known research on hind limbs on modern whales.
Creationists denied the existence of hind limbs on whales, and Ed located the photographs which confirm the existence of limbs on whales. [I thank him for that.]
It is quite easy for Creationists to deny vestigial hind limbs on whales, due to the fact that cetacea (whales and dolphins) are so far along in the evolutionary process, that today little or no evidence remains in their anatomy to demonstrate thier evolutionary history. That is, to say for the common person with no background on biology or paleontology. For scientists, the evidence is abundant and overwhelming. But for the common person, such as myself, modern whales offer only limited evidence of their land-dwelling, quadruped ancestors. For me, that vestigial organs would slowly disappear on whales, is only a matter of common sense -- that is, if Darwinian natural selection is true, and I believe it must be. Aside of the rare fossil finds Paleontologists recover from obscure desert regions where oceans once existed, whales simply do not offer the kind of empirical evidence Creationists demand to see. To elaborate on this point, myself and Ed Babinski had the opportunity to correspond with Professor Hans Thewissen in 2003 on photographs contributed by the Milwaukee Public Museum of their Humpback and Pilot Whale Display, both of which contain vestigial Pelvis bones. Professor Thewissen explained, the mount in the museum does not contain the femur, because it is made of cartilage. That portion of the hind limb on the whale is missing, but yes, the whale has one.
However, this lack of visual evidence is not the case with Sirenians (Sea Cows, Dugongs, Manatee).
A note of interest for Sirenian lovers: Hans Thewissen has moved his site, and has added a page on Sirenian fossils!
I had a life-changing experience a couple years ago viewing PBS Reading Rainbow episode "Sam the Sea Cow" where LeVar Burton visits various manatee / marine mammal preserves, including Sea World. I stood in awe [along with the information I'd picked up from the PBS "Evolution" series, and National Geographic's "Evolution of Whales"] as I saw LeVar Burton holding a manatee flipper in his hand, seeing it with my own eyes, these "elephant toenails" on a sea mammal! Including numerous other similarities with elephants that Dr. Lowe explained to LeVar Burton and the camera crew. I had trouble digesting that amazing video which you can see by visiting Sam the Sea Cow in Real Media Format. [Click on the "Preview this Video" link]. These are not "hypothesized" vestigial toenails. These toenails exist in our own time, that we can see with our own eyes, in this day and age! There is no denial of toe nails on manatees. The manatee perhaps, will lose their toenails in another twenty thousand years -- perhaps another fifty thousand years. Perhaps another million. Perhaps twenty million years from now. And, when nature has ran its course, and toenails have disappeared from sirenians (if they're not driven to extinction before that time), a Creationist, somewhere, will deny fossilized toenails on sea cows, as they have adamantly denied hind limbs on whales. We are living in a time, where the evolutionary process has not yet finished running its course with Sirenians. We are blessed to see the phenomena of evolution in progress! With Sirenians, unlike the majority of Cetaceans, it's getting there -- but it's not complete. The traces of toe nails (and other traits) remain on the Sea Cow. We're not so fortunate in the case of whales. We would have seen and taken for granted hind limbs on whales, had we lived thirty five million or more, years ago.
I am very pleased to have been granted permission by the Producers of Reading Rainbow to share this segment of "Sam the Sea Cow" which reveals the toenails and other traits in common with elephants. Along with the photographs (below), please do visit the PBS site and see the video segment for yourself here. [Click on the "Preview this Video" link].