Dino-Mites
A piece of Canadian Cretaceous amber with a preserved feather and associated mite. |
It appears that mites were some of
the first animals to walk on land some 400 million years ago. They would later
give rise to the group of animals we now call ticks, but that wouldn’t come
along until much later. In 1998, eggs from a type of feather mite were found on
feathers belonging to a Cretaceous (120 million years ago) dinosaur from
modern-day northeast Brazil. Later researchers claimed these eggs to be more
similar to mites in the family Cheyletoidea (these guys cause a form of
dermatitis known as “walking dandruff” in modern mammals and birds).
T-Rex Ticks?
Ticks were once thought to have
originated about 42 million years ago on the modern continent of South America.
However, a recent discovery of a tick stuck in amber from New Jersey pushes
tick origins back to about 90 million years ago. This fossilized larval tick
was named Carios jerseyi and was a
type of soft tick. Unlike most soft ticks, this species had dozens of tiny
hairs aligned in two rows along its back. Because this is the only known
specimen from this time period so far, its gut contents can not be examined for
the blood of dinosaurs. However, because it lived at the same time, and because
we know that ticks today feed on everything from birds, to mammals, to lizards
and snakes, we can assume that this species probably did feed on dinosaurs.
Carios jerseyi |
Tongue Worms in Dino-Lungs?
Pentastomids are a group of
crustaceans that date back to 500 million years ago! These little guys live in
the respiratory tracts of terrestrial vertebrates. Close to 85% of modern
pentastomids are found in the lungs of reptiles. Being present so early in the
fossil record indicates that these animals have had associations with
vertebrates for a very long time. Given what we know about these arthropods, it
wouldn’t be too much of a stretch to assume that they may have been present in
dinosaurs. From what little bit I’ve read, it seems that many scientists are
convinced that dinosaurs played host to tongue worms….however, I have not found
any studies confirming this. The problem is that soft-bodied invertebrates, as
well as dinosaur lung-tissue, does not preserve well over millions of years.
Will we ever know if these guys parasitized dinosaurs for sure? Maybe…we are
learning more and more as technology progresses…but for now, suffice it to say
that they were probably a common dino-parasite.
A modern-day pentastomid (Armillifer agkistrodontis) from a snake. |
Insects
Insect populations exploded during the time of the dinosaurs. We are talking, like dragonflies with two-foot wing spans exploded. This was because the environment was right for them, the world being covered in warm-temperate, subtropical, and tropical biomes. Naturally, many of those species were blood-feeders, such as everyone’s least favorite little blood-sucker, the mosquito. In addition, there existed many other species of biting flies, and the lice and fleas I mentioned in a previous post. With the arrival of blood-feeding insects, it was only natural that these animals would become choice candidates as vectors for disease transmission.
Insect populations exploded during the time of the dinosaurs. We are talking, like dragonflies with two-foot wing spans exploded. This was because the environment was right for them, the world being covered in warm-temperate, subtropical, and tropical biomes. Naturally, many of those species were blood-feeders, such as everyone’s least favorite little blood-sucker, the mosquito. In addition, there existed many other species of biting flies, and the lice and fleas I mentioned in a previous post. With the arrival of blood-feeding insects, it was only natural that these animals would become choice candidates as vectors for disease transmission.
Many forms of diseases we know about
today are blood-borne. For the sake of brevity, which is as we all know the
soul of wit, I will say that the insects that lived with, and probably feed
upon, the dinosaurs were probably carrying various infectious agents. These
could have been viral, bacterial, or parasitological (as in protists or
intestinal worms, perhaps). There have been instances of finding sand flies
preserved in amber, which we know to be the vectors of Leishmania today. Dr. Poinar, author of “What Bugged the Dinosaurs?”,
has spent much of his time looking at specimens from amber such as the one
mentioned above. He was quoted as saying this in an interview I found online:
“Our research
with amber shows that there were evolving, disease-carrying vectors in the
Cretaceous, and that at least some of the pathogens they carried infected
reptiles.”
He went on to discuss how big of a
role insects played in the gradual downfall and eventual extinction of our archosaurian
predecessors as best I could understand from reviews about the book. Needless
to say, this one is definitely makings my “must-read-someday” list. Apparently he also co-authored another book called "The Quest for Life in Amber", which may have also made said list.
Moral of the Story
When a conversation turns to
dinosaurs, we don’t often think about how arthropods may have annoyed them as
much as they sometimes annoy us. It is pretty amazing to think of all that we
have learned about dino-parasites, but even more amazing is that which we have
yet to learn or what information has been lost to evolutionary history. So at
the next party you attend, you should casually mention how far back into the
fossil record you have to reach to find the presumed origins of arthropods like
mites and pentastomes. Maybe you will
start up a vibrant conversation with someone worth talking to. If so, you
should most certainly ask them to join you for a cup of coffee sometime and the
two of you can contemplate the role of parasitism in the extinction of the
dinosaurs. You could make a new friend just because you read my blog. You are
welcome. ;)
Ok that = crazy neat! Maybe you should continue to post these on my actual page so I can keep up with them. lol. By the way, you should totally think about going into textbook writing... because entertaining textbooks are the best. :)
ReplyDeleteI'll do that for you...but only because I <3 you! It would be awesome to have a textbook with my name on it, but from what I've heard recently about writing textbooks, I'm not sure if it's the kind of headache I would want to undertake. It sounds like a real pain, and it's expensive, to get permissions for all of the images. Blah!
ReplyDelete