Dead Things That Might Be Under Your House!

The line between hallowed ground and home is a thin one in Houston. Our city isn’t exactly known for the preservationist spirit of its citizens, and looking out your window at skyscrapers or suburban expanses, you may not see any visible evidence of the city’s history, but that’s exactly the problem: You don’t see it because it’s under your feet!

Are you dubious of the of this assertion? Well, after we’re done I guarantee you will never rest assured that you are the only resident of your happy home. We will begin long ago, past the stretch of collective human memory. In this time, herds of Mammoths roamed over a cold savannah that stretched across North America. In this unfamiliar landscape, Giant Sloths thundered here and there using their huge, retractable claws to literally scratch an existence out of the land, and Glyptodons fought off saber-tooth cats.

When you think of Paleontology, you don’t think Houston, but the remnants of that epic world are here. In the Paleontology Hall of HMNS Sugarland there is displayed the skeleton of a giant armadillo, HolmesinaIn North America during the Pleistocene, armadillos the size of Volkswagen Beetles roamed Texas; Holmesina is a smaller species of armadillo cousin from that era. When I say “smaller”, I mean that instead of being 7 to 10 feet long and up to 5 feet tall, they were closer to 6 or so feet long and a couple feet tall. Still quite large… Our specimen was discovered in 1955 by Florence Dawdy, along with her son and a friend on Brays Bayou, not far from HMNS!



Holmesina specimen at HMNS Sugarland

A giant sloth was discovered not long ago in the Galveston area. Many don’t know this, but there was a time when the coast was a hundred miles further out from Houston than it is today, but as the glaciers melted at the end of the last ice age and ocean levels rose the graves of countless Pleistocene prey and several Human habitation sites were swallowed by the Gulf of Mexico. Occasionally spear points or fossilized camel bones will wash up on certain beaches in the area, like High Island. 


Megatherium, a type of ground sloth. Note the giant claws, which were retractable,like a cat’s claws!

A Columbian Mammoth was discovered in a sand pit in the town of Clute near the Lake Jackson area in 2003. Columbian mammoths are the less hairy cousins of the famous Wooly Mammoths. Both species thrived in the vast grasslands that stretched from Minnesota to Mexico 10,000 years ago. The Wooly’s tended to stay further north, while the Columbians roamed in the warmer Southern regions. 



Columbian Mammoths

The Columbian Mammoth was named after Christopher Columbus, the most famous explorer of the New World, because this species of mammoth is unique to the Western Hemisphere. The one found in Clute was the first mammoth to be discovered in the Texas Gulf Coast area. The mammoth is nicknamed Asiel, and if you’re ever in the area, you can stop by “Asiel’s Restaurant”, which boasts a replica of the skull, and an exhibit including some real fossils of deer, camel, and giant sloth that were also discovered in the area.

So there are indeed a few paleontological discoveries that have unexpectedly popped up in the Houston area. And who knows, maybe the next find is under you right now! Next week we will turn the dial of geological history forward to the era of human occupation to discuss some more intriguing specimens found lurking beneath the surface of our city.

Incidentally, we happen to have an entire Hall of Paleontology devoted to prehistoric North America here at HMNS, so next time you’re visiting, be sure to check that out. We have examples of all three animals discussed in the article.

No Bones About It: Forensic Workshop Provides Evidence for an Awesome New CSI Summer Camp

At the Houston Museum of Natural Science, we understand the value of education, as it is an integral part of our overall mission. The value placed on education extends to museum employees as well. Whether through offering CPR training to employees or encouraging participation in continuing education in disciplines in which they are already trained, there is always opportunity for growth. I benefited from this forward-thinking mindset in April. Let me tell you a little bit about this amazing opportunity.

I participated in the Forensic Anthropology and Skeletal Recovery workshop presented by the Forensic Science Center. This 40-hour experience was spent learning to identify bones as human or animal, creating biological profiles using skeletal remains, and recovering buried remains along with associated evidence. In addition to furthering my education, I was able to meet some interesting people, like my new friend pictured here.


Forensic anthropology is the application of anthropology to criminal investigations. The forensic anthropologist is often called in to help in the recovery of skeletal remains and to create biological profiles using bones to help identify an unknown individual. Let me tell you a little bit about how it works.

First thing’s first — if what looks like a bone is found, whether it could be something else must be determined. There are a surprising number of things that look like bone. Even anthropologists can be fooled from a distance. Below is a picture taken on my trip to Saudi Arabia; the item is about the size of a half dollar.  At first glance, I thought it was bone, but on closer inspection, I decided it was not. It is most likely a piece of coral, fashioned into a circular shape many years ago, by human hands. So, not bone . . . still cool. I can live with that.


The fact that it was found next to the piece below, which is absolutely bone, made it much more likely to assume the above piece was bone as well.


Once you determine the specimen is a real bone, you need to find out if it is human or from some other type of animal. This is harder than you might think. All mammals have the same skeletal template. This means all mammals have all of the same bones, in approximately the same places. However, the morphology of the bone, which is its shape, and how the bones relate to each another, differs between humans and other animals. Bone is classified as human or not by considering its size, shape, and structure. 

We examined two tables filled with all kinds of bones, both human and other. What an amazing experience! You can read about identifying human bone, but you really don’t get a feel for the process until you’ve had the opportunity to touch them and hold them in your hands. Check out one of the tables, filled with long bones.


Ok, great, let’s assume the bone we’ve been talking about is real and it’s human. Now what? Well, we need to establish what elements of the skeleton are present and how many individuals are associated with the burial. This is done by laying the bones out in the order you would find them in a living person. This is called the anatomical position. When done, you will know what parts are missing and it also allows the opportunity to scan each bone for trauma.

Turns out that laying out a skeleton isn’t too hard, until you get to the ribs (and hands and feet, but we weren’t required to do that). My partner and I get points for being clever. We discovered a number on the side of each rib. This made things go much faster! What can I say? I’m competitive. Given time, we would have gotten it right without the help of numbers; I say work smarter, not harder.


The next question — are the remains modern or ancient? Police will not be interested in an ancient Native American burial, but they will be interested in any human remains less than 50 years old. Whether bones are ancient or modern can often be determined by associated artifacts. Cell phone? Most likely modern. Pottery shards? A good bet it’s ancient.

The next order of business is to identify the person to whom the skeleton belongs. This is done by creating a biological profile, which includes the estimated age, sex, ancestry, and stature of the individual. Knowing this information helps investigators narrow the amount of potential candidates from the missing persons database. When possible matches are found, dental X-rays or unique identifiers such as healed fractures or bone abnormalities are used to make a positive identification.

Next, we reviewed how to determine probably ancestry and sex using the skull, and then worked with a variety of specimens of varying ancestry, both males and females. This particular skull was a real challenge.


Some were a little easier.


And some skulls were as interesting as they were simple to identify. Check out this awesome specimen. It was modified into a teaching aide. Sections of bone were removed and then replaced with hinges so they could open to reveal substructures and close to observe surface structures. Notice where a portion of the jaw was removed to illustrate the root structure of the teeth. Absolutely fascinating!


Later we took a field trip to the crime scene house where they train law enforcement personnel. So cool! We worked on surface recovery of skeletal remains in the yard surrounding the house. This included gridding out the entire crime scene into one-meter squares using stakes and string. Then we got busy documenting the scene using photography and sketches.

After the initial preparations, we cleared the entire area of grass and debris. This was quite an undertaking, but I did discover three .22 shell casings because of our careful work. Our skeleton was rocking some awesome boots, as you can see below.


The last two days we spent on the recovery of skeletal remains from a clandestine burial. This is hard work! The first step was to find the grave using a probe to penetrate the ground looking for disturbed soil. Disturbed soil is more loosely packed than undisturbed soil, making the probe slide easily into the ground. Once located, we gridded out our work space, removed grass and debris, and collected surface evidence. Pink flags indicate the likely outer limits of the burial site.


It was then time to move a ton of dirt, a little at a time. All dirt was sifted, after removal, to collect evidence that may have been missed during excavation. Precise measurements were taken for anything found associated with the burial. It could be tedious at times, but it really got exciting when things started to turn up! We found our skeleton about four feet down. That’s a lot of digging when using a hand trowel, a paint brush, and bamboo skewers!


I’m excited to put my new training to work as I prepare brand new forensic science Labs-on-Demand classes and a brand new CSI camp experience for Xplorations Summer Camp 2017. It will be amazing for students to be able to interact with real bones and engage in the kinds of processes used by practicing forensic anthropologists!

A New Branch: How anthropologists added Homo naledi to our family tree

In a well-deserved world-wide wave of publicity, the existence of a new hominid species was announced recently. Fossil hominins were first recognized in the Dinaledi Chamber in the Rising Star Cave system in October 2013. Now, some two years later, and after exhaustive analysis of more than 1,500 bone fragments, the team decided to go public with this first milestone: the identification of a new human ancestor.

A selection of these bones have been scanned and uploaded to the internet. They also wrote up their findings and published them in an open-access source, eLife, rather than more established channels such as Nature or Science. (A brief side note: as can be seen in this video, one of the thirty specialists involved in the initial evaluation of these remains was Viktor Deak, who was part of the Houston Museum of Natural Science’s team putting together the Lucy’s Legacy exhibit as well as the section on human evolution in the museum’s Morian Hall of Paleontology.)


Fossilized bones discovered in Rising Star Cave in South Africa belong to a new species of hominid.

While social media are currently lit up with all kinds of references to this new species, it might be interesting to address this fundamental question: how does one define a new
hominid species? In other words: “Why is naledi called naledi?“

A starting point in this process is to identify a type specimen. Such a specimen is described in great detail, listing the similarities to and differences from closely related species. There is no central authority that decides on the validity of a species. Rather, this depends on the acceptance of such a designation within the scientific world. New discoveries and more information have given impetus to revisit previous species designations and change them.

As a result, “[i]f two type specimens are later determined to belong to the same species, then the first one named takes priority. For example, when it was decided that the 2nd known australopithecine fossil, assigned to Plesianthropus transvaalensis, actually belonged to the same species as the first that name became invalid and all Plesianthropus fossils were reassigned to Australopithecus africanus.


Skull fragments from the holotype specimen show Homo naledi had a brain about the size of an orange.

If it is decided that the fossils previously assigned to a species actually belong to two different species, then the type specimen and any other specimens belonging to the same species as it keep the old name. The other fossils will take the name of whichever specimen among them is first used as a type specimen for a new species definition. An example is Homo habilis (type specimen OH 7); the species Homo rudolfensis, with type specimen ER 1470, consists of fossils formerly assigned to habilis.”

This new species belongs to the genus Homo. Traditionally, one is a member of that genus if the following criteria are met (Since these are set by human researchers, they are subject to periodic re-evaluation):

  • Brain size: at least 600 cubic cm.
  • Possession of language
  • Opposable thumbs and precision grip
  • Ability to manufacture (stone) tools

We all belong to the genus Homo, species sapiens and subspecies sapiens. We are “Humans, wise, wise” or “very smart humans.” (Since we are the humans investigating ourselves and our ancestors, it should not come as a surprise that we have kept the most honorific label for ourselves.)

If we translate Homo naledi into plain English, we can start with naledi. The species was named Homo naledi; ‘naledi’ means ‘star’ in Sotho (also called Sesotho), one of the languages spoken in South Africa.

According to the research team, the definition of the new species was not “based on a single jaw or skull because the entire body of material has informed our understanding of its biology.”

Interestingly, Homo naledi’s brain size is in the 400 to 600 cubic cm range, yet they are considered to be members of the genus Homo. Here is why: “The shared derived features that connect H. naledi with other members of Homo occupy most regions of the H. naledi skeleton and represent distinct functional systems, including locomotion, manipulation, and mastication.”

Homo naledi - brain size - range

Brain size and tooth size in hominins. (Lee R. Berger et al. eLife Sciences 2015; 4:e09560)

Fossil Dating

One aspect currently left unanswered is when Homo naledi lived; the scientists offer what-if scenarios for dates ranging between one and two million years ago, some even more recent. These are just that: scenarios. They do not provide a date, as none exists at this point.

That brings up the question: how does one date a fossil? Knowing when a human ancestor lived helps us understand the affiliations of different species and who might have evolved from whom. Scientists have access to a wide array of dating techniques.


Homo naledi had human-like hands, though smaller than our own.

Radiometric Dating

Several techniques measure the amount of radioactive decay of chemical elements. Known as radiometric dating techniques, these include potassium-argon dating, argon-argon dating, carbon-14 (or radiocarbon), and uranium series. This radioactive decay occurs in a consistent manner over long periods of time. A benchmark concept in using this approach is that of a “half life,” defined as “the time it takes for one-half of the atoms of a radioactive material to disintegrate.” Early hominid sites in Eastern Africa have stratigraphic affiliations with volcanic layers. These layers can be dated with the radiometric dating techniques just described. As we will see below, the situation in Southern Africa is different.

Measuring Stored Electrons

Thermoluminescence, optically stimulated luminescence and electron spin resonance measure the amount of electrons that get absorbed and trapped inside a rock or tooth over time. The application of these techniques to date fossils highlights how the study of human origins truly is a multi-disciplinary effort.

Thermoluminescence “(or TL) is a geochronometric technique used for sediment. The technique has an age range of 1,000 to 500,000 years. The technique is used on sediment grains with defects and impurities, which function as natural radiation dosimeters when buried. Part of the radioactive decay from K, U, Th, and Rb in the soil, as well as contributions from cosmic rays, are trapped over time in sediments. The longer the burial, the more absorbed dose is stored in sediment; the dose is proportional to a glow curve of light obtained in response when the sample is heated or exposed to light from LEDs. Greater light doses indicate an older age.”

Luminescence dating is “a form of geochronology that measures the energy of photons being released. In natural settings, ionizing radiation (U, Th, Rb, & K) is absorbed and stored by sediments in the crystal lattice. This stored radiation dose can be evicted with stimulation and released as luminescence. The calculated age is the time since the last exposure to sunlight or intense heat.”


Homo naledi’s feet appear nearly human.

Finally, “electron spin resonance (ESR) measures the number of trapped electrons accumulated, since the time of burial, in the flaws of dental enamel’s crystalline structure. At sites containing human and animal teeth, ESR can be used to determine how long the teeth have been in the ground, but finding teeth at an archaeological site is unusual, so this dating method is not as common as thermoluminescence or radiocarbon dating.”

Another dating technique altogether is paleomagnetism. It compares the direction of the magnetic particles in layers of sediment to the known worldwide shifts in Earth’s magnetic field, which have well-established dates using other dating methods.

Sites in Southern Africa cannot be dated with techniques outlined earlier. A lot of the fossil remains are found in a stone matrix, rather than on the surface. These fossils can be dated using biochronology. Most often – though not always – hominid remains are found in stratigraphic association with animal bones. Quite often, these animal remains belong to animal species that roamed elsewhere in Africa, where absolute dates are available. In this way, sites that do not have radioactive or other materials for dating can still be given a reliable age estimate.

Finally, one can estimate the time that elapsed since two species separated from a common ancestor. This is based on the concept of a molecular clock. This method compares the amount of genetic difference between living organisms and computes an age based on well-tested rates of genetic mutation over time.  Since genetic material (like DNA) decays rapidly, the molecular clock method cannot date very old fossils. The most ancient DNA that has been retrieved thus far dates back to 300,000 to 400,000 years ago.

There is no doubt that more information will be forthcoming from the Rising Star Cave system in South Africa. Over the last two years, the researchers have literally scratched the surface of what is in the cave. As mentioned earlier, the genus Homo is defined by a number of features. One of these used to be that we buried our dead. This appeared to have happened in this case as well. Once the remains are dated, we will know if this fundamentally human trait extended further back in time than we ever imagined. Or not.

Dipsy the Diplodocus is back at HMNS!

After a 2 year absence, “Dipsy” the Diplodocus is back at HMNS!  Making it’s debut back in 1975, Dipsy was the first dinosaur to call HMNS home. In 2013, our Diplodocus was de-installed from its original place in the Glassell Hall and sent off for a much needed spa retreat in Utah. While there, the bones were carefully cleaned and a new mounting frame designed. This week, she arrived back in Houston and was permanently installed in our Morian Hall of Paleontology.

Diplodocus installation, March 2015

Spine, tail and rib bones go up first. Followed by the legs.

Front leg installation.  Dipsy's stance has been modified from it's previous posture. Now, the skeleton assumes a tripod stance, as if rearing up to feed on leaves.

Front leg installation: Dipsy’s stance has been modified from it’s previous posture. Now, the skeleton assumes a tripod stance, as if rearing up to feed on leaves.

Associate Curator of Paleontology, David Temple, overseeing the installation process.

HMNS Associate Curator of Paleontology, David Temple, oversaw the installation process.

 Fun Facts about “Dipsy” the Diplodocus

  • This particular Diplodocus skeleton is a holotype for Diplodocus hayii. A holotype is a single physical example (or illustration) of an organism, known to have been used when the species was formally described. HMNS is the only place in the world where you can see a Diplodocus hayii on display.
  • Paleontologists don’t know for sure whether Dipsy is male or female.
  • Diplodocus hayii were herbivores. Their skulls, however, have many small, sharp teeth. These were used for stripping plants, not for chewing.
  • This skeleton is 72 feet long and about 25 feet high.
Dipsy's skull was the last piece  to be installed. Notice the small, sharp teeth present.

Dipsy’s skull was the last piece to be installed. Notice the small, sharp teeth present.

For more photos of the installation, visit out Instagram page.