Thursday, April 16, 2015

Quoteblog of the Day: Part 2

"Somewhere, something incredible is waiting to be known"

Carl Sagan

"I abide in goodly Museum, 
Frequented by sages profound:
'Tis a kind of strange mausoleum,
Where the beasts that have vanished abound.
There's a bird of the ages Triassic,
With his antediluvian beak,
And many a reptile Jurassic,
And many a monster antique".

May Kendall
 (from 1887 "Ballad of the Ichthyosaurus")
(English poet)

"In vertebrate paleontology, increasing knowledge leads to triumphant loss of clarity"

Alfred S. Romer 
Quote by Keith Thomson

"I want to find a voracious, small-minded predator and name it after the IRS"

Robert T. Bakker

I hope you enjoy these! Some I found at Todayinsci, others from the literature. 

Stay tuned for more bits from the paleoworld!
Happy Earth Day (4/22). 

Tuesday, April 14, 2015

Titanic Sinks. Great Loss of Life!

April 15, 1912: "New Titanic Sinks, 1500 Died".

Titanic Sinks, Great Loss of Life! This was one of the first famous headlines to be published that year. Public domain images from here.

I am fascinated by the past, and I have always been fascinated by the history surrounding the tragedy of the RMS Titanic. Exactly today (the day of the post) we celebrate 103 years of the tragedy, and I thought of doing a small post commemorating on the subject. I guess this post will figure into my "history-ephemeral-ramblings". Here we go.

RMS Titanic photographed on Cork harbor, 11 April 1912. Courtesy of Wikipedia.

Historical Gist

The RMS Titanic has gone down in history as the worst, or at least as the most famous ocean-navigation disaster. Many myths and urban legends have served as popular explanations as to why she encountered that fateful iceberg in the North Atlantic on 14 April 1912, at 11:40 pm (ship's time) (Maltin, 2012). What seems true, as told by survivor accounts, is that it took the ship approximately 2 hours to sink, loudly breaking in half in the early hours of April 15. Of course, oceanography, climatology, and aspects of material technology provide clues that help elucidate the tragedy. I will explore only a few here.

Several ocean-climate related hypotheses could explain such titanic disaster. One is the presence of the icebergs further-than normal south of the Atlantic. During the days before the incident, icebergs were observed by nearby ships surrounding the area where the RMS Titanic sank. Some were even photographed.

Others have argued that the disaster was due to human error. Deck observations were apparently sporadic on the night Titanic sank, and the ship was cruising at top speed. Moreover, there is even considerable debate concerning likely engineering error. This is founded on its speedy construction, bad rivets, and other second-rate construction materials. The idea was to make the Titanic the fastest, largest, most luxurious ship of the White Star line, fast. The crew wanted to dash across the Atlantic, making harbor in New York in record time.

North Atlantic iceberg drift routes. Map from Atlas of Canada, modified by Patrick Lockerby at Science 2.0.

The occurrence of the icebergs is explained through oceanography. North Atlantic icebergs form and dislodge from landlocked glaciers. Some are carried by the Transpolar Drift Stream, which carries ice to the Greenland sea and the North Atlantic from as far as Siberia and the North Pole. Other iceberg sources include the circumpolar region and the Greenland Ice Cap. Icebergs often transport rocks, which they piggyback as relics of they landlocked origins. These are called drift stones, as the one below.

Piggybacking drifting relic on a melting iceberg off the Hubbard Glacier in Alaska.

Ocean currents move clockwise around Greenland, flushing icebergs floating down its coasts and in the Greenland and Labrador sea. Often, they may get further south where they meet slightly warmer waters coming up from the Gulf Stream. The icebergs that make it further south, say about near 45 latitudes, get there carried by coastal currents such as the Labrador Current and the East Greenland Current.

As huge slabs of ice, icebergs float easily over water because ice is less dense than ocean water. This is due to the crystalline shape of the molecules in frozen water, which in turn decrease overall density. Trivia bit: by definition, ice could even be classified as a metamorphic rock.

Location of RMS Titanic's final resting place in the abysmal plain off the Newfoundland continental shelf.

Icebergs float down the coast carried by such currents until reaching the upper limits of the Gulf Stream. The Gulf Stream at this latitude remains laden with warmer, saltier water before becoming the North Atlantic Current (or NAC) closer to Iceland. Icebergs rarely make it further South than these latitudes because they either melt during the journey or by meeting the Gulf Stream.  Check this awesome Scientific American article on the science behind the tragedy here. Also, see Maltin (2012) for other interesting hypotheses that come really well together to explain this tragedy.

Iceberg photographed from the deck of the Prinz Albert in the morning of 15 April 1912 by its chief steward. The steward photographed it because of a visible smear of red paint on the iceberg. He did not know about Titanic's tragedy yet! 

Simply, the RMS Titanic intercepted icebergs drifting further down their major drift route near the shelf of Newfoundland, despite the multiple warnings of observed icebergs in the region. This was not abnormal to seasoned North Atlantic seamen. Many basic textbooks, much older than the Titanic herself, already indicate the origin and drifting patterns of icebergs (as an example see LeConte, 1886:56-58), and therefore, this knowledge surely did not escape experienced seamen. More so when so many other ships alerted the Titanic to mind observed icebergs in the region.

It was her maiden voyage and she was sprinting pristine out of the White Star docks in Belfast, Ireland. The result of the marriage between human technology, its culture, and the random probability of the encounter between human error and nature. The results of that concoction lie now scattered on the abyss, slightly off of Newfoundland's continental shelf, 4000 meters deep.

RMS Titanic before departure from the Southampton docks, on 10 April 1912.

The Archaeology of the Wreckage

One of the aspects that fascinate me the most about Titanic lore is the anthropology or archeology of the wreckage. The last tallies of the disaster put the loss of human life at 1,517 from the 2,223 she was carrying (Maltin, 2012). There was also a high loss in materials. Of course the ship and everything in it. Luxurious or naught are now encased around in deep oceanic sediment. Within these there are lost treasures, but unlike as told by Titanic legends, there were no diamonds or gold bullion cases aboard the liner. Probably, the most expensive portable on board was a neoclassical oil painting titled "La Circassiene a Bain" by Merry-Joseph Blondel in 1814, billing at about 6 million dollars then (New York Times, 16 January 1913). See it here.

Since the discovery of the wreckage in 1985, artifacts have been extracted from the site for several purposes. One of them, as you guessed it, is for exhibition. I have attended two of these exhibits (there is one permanent at the Luxor Hotel in Las Vegas, Nevada), and they have been extraordinary in their organization and scope of the artifacts included.

On the 100's anniversary of the disaster, photographs of human remains surfaced. These are the first to be readily plausible and were published by the Herald Sun (here). There are probably more remains encased within compartments of the decomposing ship on the bottom of the ocean. Check out NOAA's RMS Titanic Panoramio here.

Time stopped timepiece recovered from the RMS Titanic. Time-frozen at 2:28 am, around the time when she finally went fully under. Free public domain image from here.

To me, the joyful aspects of working with historical pieces, be it fossilized bones or pottery sherds, is that they serve as the closest thing we have to a time machine. These artifacts are a sort of window to the past. Like in the presence of museum specimens, as I shared in my earlier museum post, artifacts have the power to transport anyone to their own time and place. One can not help but feel awed and humbled by the span of time that can separate us.  As historical fragments themselves, survivors of their circumstances, they have the potential to open such windows.

As you read this, the RMS Titanic and all its remains sleep under severe oceanic stress, from pressure, temperature, and iron-eating bacteria. It is estimated that the wreckage will be reduced to an oxidized pile of iron within our century.


Allen Butler, Daniel. 1998. Unsinkable: The Full Story of RMS Titanic.

Geller, Judith B. 2005. Titanic: The Artifact Exhibition. RMS Titanic Inc.

LeConte, Joseph. 1886. Appleton's A Compend of Geology. Appleton's Science Textbooks, Appleton and Co., New York.

Maltin, Tim. 2012. Titanic: A Very Deceiving Night. Malt House Publishing.

Matei, Sorin Adam. 2012. Titanic wreck exact location on Google Earth map of North Atlantic.

Wednesday, April 8, 2015

The Case of the Wrong Femur

The right femur on the Greater Cuban ground sloth Megalocnus rodens on exhibition at the American Museum does not belong to Megalocnus!

Figure 1: Greater Cuban sloth Megalocnus rodens Leidy 1868 (AMNH no.16876).

In the Hall of Primitive Mammals at the fourth floor of the American Museum (AMNH), close to where the dinosaurs are mounted, there is a large sloth specimen on walking position. This specimen belongs to the Greater Cuban ground sloth Megalocnus rodens described by Joseph Leidy in 1868probably the first rock star of the Caribbean vertebrate paleorecord.

But how and why did this specimen get the wrong femur? How did such detail escape meticulous and experienced scientists? Well, that story is very interesting, and the theme of this blog post.

A Bit of Background

AMNH specimen number 16876 (fig. 1) is a composite skeleton. By composite, we mean that it is mounted with remains of multiple individuals. As the story goes, the first Megalocnus was discovered by the young university student Jose Figueroa in April 1860 at the thermal baths of Ciego Montero, central Cuba. Figueroa sent his fossil specimen, a mandible in this case, to Cuba's foremost zoologist Felipe Poey then professor of comparative anatomy at the University of Havana, who at first thought it belonged to a large rodent.

That initial discovery deeply incited the serious interest of Dr. Poey's padawan, Dr. Carlos de la Torre y Huerta, who was on his way to becoming Cuba's most prominent naturalist for all times (fig. 2 left).

Figure 2: Dr. Carlos de la Torre (left) and Barnum Brown (right). Brown's picture is from his file in Wikipedia. Each photograph is circa the late 1890s.

Dr. de la Torre spent several decades collecting more specimens in other localities, later inviting the AMNH to participate in his quest. His idea was to find specimens that could be better described and composed into whole skeleton mounts. In response to his request, the AMNH sent Mr. Barnum Brown, one of their best diggers/researchers (fig. 2 right). His reputation was impressive, for he was the discoverer of the now iconic Tyrannosaurus rex!

Between 1910 and 1918 Brown collected fossil specimens from Ciego Montero, the same locality from where the first specimen originated. Their efforts resulted in enough material to mount three specimens, of which only two were completed by Adam Hermann under the supervision of Dr. Henry F. Osborn, then director of the American Museum. That third specimen was prepared by Charles Long but never mounted. The last two remain today at the AMNH.

Figure 3: Megalocnus rodens composite skeleton  prepared by A. Hermann, and sent to Dr. Carlos de la Torre, in Havana. Photograph available from Wikipedia.

As agreed by the collecting parties, one specimen (fig. 3-4) was sent to Dr. de la Torre and is now on display at the National Museum of Natural History in Havana. [ Trivia: Dr. de la Torre was so fond of his Megalocnus mount that he used to take pictures of it and exhibit it everywhere he could, like that on fig. 4]. The other became a walking mount displayed as a separate exhibit at the AMNH. That specimen is now specimen no. 16876, and it bears the right thigh bone of Parocnus browni; another extinct Greater Antillean ground sloth of similar proportions (fig. 4).

Figure 4. Dr. Carlos de la Torre and the climbing mount of  the Megalocnus rodens. Photograph circa 1920. The bust on the left is Felipe Poey, luminary naturalist of the 19th century.

The Case

The specimens sent by Dr. de la Torre and those later collected by Brown comprised the main Megalocnus collection at the AMNH (plus other fossil verts). This collection was first studied by the renown paleontologist  Dr. William Diller Matthew along with de la Torre (1915). By 1919, Dr. Matthew had published two quick articles on the subject, but the main corpus of work was never finished. That responsibility later fell upon Dr. Carlos Paula Couto, who completed the quest (Matthew and Paula, 1959; Paula, 1967). As a posthumous note (Matthew, 1931) had installed Mesocnus browni, who figures into the story as Parocnus browni mentioned above. So named browni in the honor of Mr. B. Brown.

There seemed to be several good reasons for that erroneous mount that escaped Dr. Osborn, Hermann, Matthew, and later Paula Couto. The most reasonable are that both Megalocnus and Parocnus are anatomically similar in skeletal morphology and body size. The differences we understand now to be of specific value to them, such as the presence of a bony crest on the femur shaft known as the third trochanter, were plausibly masked by their similarity. This equivocal assignment is exemplified in plate 20 of Matthew and Paula's (1959) publication, which illustrates a Parocnus left femur (no. 49977) identified as Megalocnus rodens rodens. In this specimen, the third trochanter is clearly visible (Acevedo et al., 1972).

Figure 4: Left, Megalocnus rodens at the Cuban MNHNCu. Right, the femur of Parocnus browni mounted on the M. rodens no. 16876 at the AMNH. Note the presence of a third trochanter on the P. browni specimen on the Megalocnus rodens on the right. The photograph on left from Hernandez-Pacheco, 1947.  

But I am not the first to make these observations. That credit we owe to Manuel Acevedo and one of Cuba's most prolific paleontologist Oscar Arredondo, who committed similar observations in their book "Cueva del Tunel" (1972). A similar note was later published by Carlos Arredondo Antunez, son of the former Oscar Arredondo, in an article on the book "Mammals in Cuba" (Arredondo, 2011:32-33). However, for whatever reason, the observations of Acevedo et al did not figure into later publications on Cuban ground sloths.

What is curious is that Carlos de la Torre  had already noted the usefulness of the third trochanter by 1910!. In an article regarding the restoration of the Megalocnus specimens, he notes (my translation) "...the femur of Megalocnus rodens completely lacks a third trochanter..." (Torre, 1910:30). By then Parocnus remains were already known to de la Torre but were under the name Mesocnus  (see footnotes on Paula Couto, 1967). Thus, this statement suggests that by 1910 de la Torre was, at least, familiar with the femoral variation in Megalocnus, and to a lesser degree with fossils from other species. So how come to Matthew, who was renown for fossil mammals, and had worked with de la Torre, moreover Paula Couto who studied the  completed Megalocnus collections did not make that distinction?
It is reasonable then to think, and I am going on a limb here (pun intended), that these differences in the appendicular skeleton were originally dismissed to individual variation or sexual dimorphism as asserted later (de la Torre, 1916; Acevedo et al., 1972; White and MacPhee, 2001; Silva et al., 2007). These likely extended to the presence or absence of the femur's third trochanter. Today, such differences are considered a distinctive characteristic that helps to separate the sloth's species.

...So What? 

But doesn't this seems a bit trivial? Why does it matter or why is this important? Well, bits make up a whole, and in science every little bit of information is useful. Paleontology, like most of the historical sciences, depends on evidence that is too often partial or incomplete. We rarely find whole, well-preserved specimens from which we can compare whole skeletons, skin or feather color, or DNA, in order to understand what constitutes a species in any given group. In the practical sense, detailed anatomical distinctions allow us to separate and name which organisms belongs to what group, making our communication and distinction of such organisms easier. Therefore, by understanding the little anatomical details we can induce from which group did the fossil belong to and what was its way of life, and its evolutionary history. All these are basic clues to understanding prehistoric life in general.

This is not to emphasize on the error, but on the fact that science is always evolving; growing and relearning from its own mistakes and previous knowledge. This example highlights the importance of details and continuation of research in science, even in minutiae that seemed to have been resolved. The extinct sloths were an integral part of the insular ecosystems in our most recent past and provide a window into the understating on the diversity and extinction of mammalian life in the prehistoric Caribbean.

...Gist on Ground Sloths

Ground sloths are mammals of the order Pilosa, where they are related to armadillos, anteaters, and tree sloths. The Antillean sloths belong to the Megalonychidae family. This is a family that includes the behemoths Megalonyx from North America and the Antillean species that reached well over 50 kg body weight like the Megalocnus and Parocnus of our story. The fossil record indicates their presence in the Greater Antilles during the Oligocene (~ 32 million years ago) and the Miocene (~ 23-5 mya). These oldest records come from extraordinary fossil finds in Cuba and Puerto Rico. Greater Antillean ground sloths seem to have experienced great diversity during the Quaternary, the last several million years or Earth's history, only to disappear about 4000 years ago (MacPhee et al., 2007). Incidentally, their extinction seems to coincide with the time of the Amerindian population of the Antilles. Whether they were already endangered when the Amerindians arrived in the Greater Antilles or if they were killed off by them is still a matter of debate. But stay tuned, we may have more on this issues very soon!


Acevedo Gonzalez, Manuel, Oscar Arredondo y Noel Gonzalez Gotera. 1972. Cueva del Tunel. Editorial Pueblo y Educacion.

Arredondo Antunez, Carlos. 2011. Los peresozos extinctos. 29-37 pp. En Mamiferos en Cuba (Eds. R. Borroto-Paez y C. A. Mancina). UPC Print, Vaasa.

Hernandez-Pacheco, Eduardo. 1947. Paleontologia, 3rd ed. Int.Gallar, Spain.

MacPhee, R. D. E., M. Iturralde-Vienent, and Osvaldo Jimenez Vazquez. 2007. Prehistoric sloth extinctions in Cuba: Implications of a new "Last Appearance Date". Caribbean Journal of Science, 43: 94-98. 

Matthew, William D. 1931. Genera and new species of ground sloths from the Pleistocene of Cuba. American Museum Novitates, 511.

Matthew, William D. and Carlos de Paula Couto. 1959. The Cuban Edentates. Bulletin of the American Museum of Natural History, 117.

Paula Couto, Carlos. 1967. Pleistocene Edentates of the West Indies. American Museum Novitates, 2304.

Silva Taboada, Gilberto, William Suarez Duque, and Stephen Diaz Franco. 2007. Comependio de los Mamiferos Terrestres Autoctonos de Cuba Vivientes y Extinguidos. Edicion Bologna, La Habana.

Torre, Carlos de la. 1910. Excursion a la Sierra de Jatibonico: Osamentas fosiles de Megalocnus rodens o Mymoprhus cubensis. Sesion del 10 de Junio de 1910. Imprenta Militar, La Habana.

Torre, Carlos de la., and W. D. Matthew. 1915. Megalocnus and other Cuban ground-sloths. (Abstract). Bulletin of the Geological Society of America, vol. 26, p. 152.

White, Jennifer L. and Ross D. E. MacPhee. 2001. The sloths of the West Indies: A systematic and phylogenetic review: 201-235pp". Chapter 14 in Charles E. Wood and Florence E. Sergile (Eds) Biogeography of the West Indies: Patterns and Perspectives. CRC Press, Boca Raton.

Saturday, April 4, 2015

Quoteblog of the Day

"...Science is the best idea humans have ever had.
The more people who embrace that idea, the better."
"Science rules!"
Bill Nye (The Science Guy)

"Science is a way of thinking more than a body of knowledge."
Carl Sagan

"Nothing has the power to broaden the mind as the ability to investigate systematically and truly all that comes under thy observation in life."
Marcus Aurelius (from Meditations)

"The important thing is not to stop questioning."
"Imagination is more important than knowledge."
Albert Einstein

I hope you find these inspirational. Read on and stay tuned for upcoming adventures!