If I could be an Allosaurus: The sounds of the Jurassic

Have you ever wondered what it would have been like in the time of the dinosaurs? What they would have looked like and how they would have behaved? What the plants would have been like? Perhaps how hot it would have been, or what smells you could have smelled? What sounds would you have heard as you crouched in a bush and tried not to be found by any large meat-eating carnivores?

Broad-winged katydid (Microcentrum rhombifolium)

A group of scientists from China is filling in one small piece of that complex puzzle. A new study recently published by Gu et al. (2012) in the Proceedings of the National Academy of Sciences names a new stem (or basal) katydid (Archaboilus musicus) from the late Middle Jurassic (Bathovian-Callovian interval at about 165 Ma) of northwest China, namely from the Jiulongshan (or called the Haifanggou) Formation.

Hangingfly (Harpobittacus tillyardi)

This formation is known for several fossil species, although none of them are vertebrates. Its taxa includes the tangle-veined fly Ahirmoneura neimengguensis, the aphid Sinojuraphis ningchengensis, and the hangingflies Formosibittacus macularis, Jurahylobittacus astictus, and Mongolbittacus daohugoensis. The known flora of the formation includes the early flowering plant Xingxueanthus sinensis and the possible early flowering plant Schmeissneria sinensis. Most of these taxa are known from single specimens at the moment, but the preservation is quite exceptional. This preservation means that many features that would normally not be preserved or identifiable are within this formation and in some of these specimens. This leads directly into the new basal katydid Archaboilus musicus.



The type of Archaboilus musicus consists of the part and counterpart of a pair of forewings. Many insects today, including crickets, are able to generate sound using their wings. One of the wings has a row of "teeth", similar to a file. The other acts as a "scraper". One of the co-authors of the study, Montealegre-Zapata, stated that "When they close the wings, the teeth of the file produce vibrations that are amplified as sound by the wing membranes." Many people are currently aware of these sounds. When you are outside, or even inside, and here a cricket "chirping", you are hearing the same actions.

Type of Archaboilus musicus (CNU-ORT-NN2009001PC) showing leftand right forewings. Red arrows in B and D point to area of stridulation and where the noise would been created by the katydid, E and F help show close up versions of the two areas (from Gu et al., 2012).

Stridulation, or the ability to create sounds by rubbing certain body parts together, is well-known in various insects today. With this knowledge in hand, the researchers found that their new insect was preserved well enough to give key details about important morphology of the wings. With this, the researchers conducted thorough comparisons of the forewings of Archaboilus musicus with those of 59 other modern insects. With this comparison, the researchers were able to gain potential insight into something quite incredible and not before really found from the fossil record.

Gu et al. (2012) were able to recreate what this 165 million-year old katydid would have sounded like. Really think about that, a sound not heard for 165 million years has now been recreated. And now you can hear something that the dinosaurs and other animals from that time and region would have heard as well. It may not seem like much, but the ability to recreate that part of the late Middle Jurassic world of northwest China is truly incredible.

The sound was found to be at a low frequency, allowing it to travel relatively far distances. This, combined with the idea that the environment would have been filled with relatively wide-spaced coniferous trees like Araucaria (approximately 1.5 to 20.3 m nearest neighbor distances) and giant ferns (e.g. Angiopteris, Osmunda, and Caniopteris) occupying the lower levels of the forest understory, would have allowed for these low-pitched mating calls to travel much further distances.

Archaboilus musicus reconstructed

The researchers also found that, through comparison with a species of modern katydid, the roughly 4-inch long Archaboilus musicus would have probably been making this call multiple times every second when ready to mate. In essence, the paleoacoustic reconstruction of its call was similar to those of modern crickets, although it would have been of a relatively lower-frequency. In fact, in the movie Jurassic Park, crickets were used for background noise, and it turns out that both sound would have been similar.

Just as interesting as this new insect is what animals would have actually heard these calls while they roamed northwest China all those years ago? While no other vertebrates have been recovered from the Jiulongshan (or called the Haifanggou) Formation, the overlying Tiaojishan Formation does have a diverse assemblage of vertebrates which may have been around at the time of the lyrical Archaboilus musicus and heard its call. As a note, both the Haifanggou and Tiaojishan formations were formerly grouped together as the Lanqui Formation, but that is no longer accepted.

Darwinopterus

In the Tiaojishan Formation (mainly from Laioning), the rhamphorhynchoid pterosaurs are relatively common and include Changchengopterus pani (from Hebei), Darwinopterus modularis, Fenghuangopterus lii, Jianchangnathus robustus, Jianchangopterus zhaoianus, and Qinglongopterus guoi. The istiodactylid pterosaur Archaeoistiodactylus linglongtaensis is also present in the formation.

Along with the pterosaurs, a few other vertebrates are also present in the formation. These include the plant-eating heterodontosaurid Tianyulong confuciusi. The holotype got a lot of recognition due to a row of long, filamentous integumentary structures that appear to be on its back, tail and neck.

Tianyulong confuciusi

Anchiornis huxleyi

Along with the above-mentioned Ornithischian are two theropods that are considered either archaeopterygids or basal deinonychosaurs. Anchiornis huxleyi is a small dinosaur known from several specimens. Xiaotingia zhengi, on the other hand, is known from a single specimen. Anchiornis has gotten publicity lately due to a more in depth look at the coloration of its feathers, giving scientists a better idea of how it may have looked.  

Xiaotingia zhengi

Xiaotingia has gotten recent publicity because in the corresponding phylogeny, Archaeopteryx, long thought to be the "first bird" and a key figure in the evolution of dinosaurs to birds was positioned as a dinosaur rather than a bird. Still, neither of those are the purpose of this post.

Juramaia sinensis

The earliest known placental mammal, Juramaia sinensis, is also found in the Tiaojishan Formation. Juramaia , while not only showing the morphology and transition of a mammal from a metatherian to a eutherian, was also able to push pack this transition 35 million years earlier than had been previously thought. While quite small, this furry little friend would have been scurrying around the trees and doing its best to stay out of the clutches of Anchiornis and Xiaotingia, among other predators that I'm sure have not yet been discovered.

The Tiaojishan Formation has a few invertebrates as well including a few ostracods and a bivalve. There are also a large number of plants present in the formation. For more information on them, try the wiki page for the Tiaojishan Formation.

But, the main point of this post is to try to hear what these dinosaurs, pterosaurs and mammals, among other things, would have heard on a clear night. So, without further ado, I leave you with the movie file below. It is something that I find almost as good as bringing the insect back to life to be able to hear it. You can close your eyes and imagine it is at night 165 million years ago in northwest China. The small Juramaia scurries between your legs, a herd of Tianyulong travel through a few of the trees off to your left, an Anchiornis is sitting in a tree to your right, and you just barely catch a glimpse of a Xiaotingia gliding from a tree in front of you until you lose sight of it. Various pterosaurs can be seen through the trees, and a few land in some trees off in the distance, just visible with the setting sun. And finally you hear a katydid just a little younger than Archaboilus musicus making these calls. The ability to make the picture that much clearer shows just how incredible the science of paleontology, coupled with numerous other fields, can be.

For a different, but very good review of this incredible discovery and study, make sure to check out the post by my colleague David over at the Meniscus!


Reference

Gu J.-J., Montealegre-Z, F., Robert, D., Engel, M.S., Qiao G.-X., and Ren D. (2012). "Wing stridulation in a Jurassic katydid (Insecta, Orthoptera) produced low-pitched musical calls to attract females." Proceedings of the National Academy of Sciences, (advance online publication) doi:10.1073/pnas.1118372109