Monthly Archives: January 2015

Friday Fellow: ‘Orange Jaguar Snail’

by Piter Kehoma Boll

ResearchBlogging.orgLast week I introduced a land planarian that feeds on land snails, Obama ladislavii, or, as I called it, the Ladislau’s flatworm. Therefore, today, I thought it would be great to present a similar situation occurring backwards: a land snail that feeds on land planarians.

So let me introduce this little predator, the land snail Rectartemon depressus. Again, it is not a widely known species and thus it has no common names, but why not call it the ‘orange jaguar snail’? Species of the genus Euglandina, which are also predatory snails, are called ‘wolf snails’ by comparing them to a common predator in North America. As Rectartemon species are common in South America, we could perfectly call them ‘jaguar snails’, right?

Rectartemon depressus about to capture a land planarian Obama marmorata. Photo from Lemos et al., 2012

Rectartemon depressus about to capture a land planarian Obama marmorata. Photo extracted from Lemos et al., 2012

Found in areas of Atlantic Rainforest in Brazil, the orange jaguar snail has a yellow to orange body and a whitish shell. It is listed a vulnerable species in the Brazilian Red List, but it is not mentioned in the IUCN’s Red List.

Initially known as a predator of other land gastropods, the orange jaguar snail revealed a new item in its diet recently. During attempts to find the food items in the diet of some land planarians from southern Brazil, the orange jaguar snail was offered as a food option, but while the expectations were that the planarian would eat the snail, the opposite happened! After contacting the land planarian, the snail simply grasps it with its radula (the snail’s toothed tongue) and sucks it in very quickly, just as if it were eating a noodle!

The orange jaguar snail eagerly consumes several land planarians, both native and exotic species. It makes it one of the first known predators of land planarians. One of its prey is the Ladislau’s flatworm, so we have a snail that eats a flatworm that eats snails!

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References:

Lemos, V., Canello, R., & Leal-Zanchet, A. 2012. Carnivore mollusks as natural enemies of invasive land flatworms. Annals of Applied Biology, 161 (2), 127-131 DOI: 10.1111/j.1744-7348.2012.00556.x

Santos, S. B., Miyahira, I. C., Mansur, M. C. D. 2013. Freshwater and terrestrial molluscs in Brasil: current status of knowledge and conservation. Tentacle, 21, 40-42.

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Filed under Behavior, Conservation, Ecology, Friday Fellow

Tunnel of Time #1: Evolution – The Game of Intelligent Life

by Carlos Augusto Chamarelli

Hey everybody, PK here as usual. Today I’ll present the first of Tunnel of Time’s articles, where we shall remember and discover some of the multimedia works we’ve seen published around the world, including games, movies, documentaries, books, magazines, computer programs and anything related to biology or general sciences, influencing us and making our imagination take flight, and of course, entertaining us as they do.

Our first Tunnel of Time item will be the game primarily responsible for my interest on Earth’s history and the evolution of living beings: Evolution – The Game of Intelligent Life. Initially developed by Crossover Technologies and Discovery Multimedia in 1997, it was released in Brazil under the name “Evolução – o Jogo da Vida” the following year, under Globo Multimídia, completely translated to Portuguese. To this day I remember the day I gazed upon it’s peculiar box at the Nova America’s computer shop, nowadays a clothes store with ugly T-shirts where its noble box once stood.

A shirt with this picture wouldn’t be so bad.

A shirt with this picture wouldn’t be so bad.

The game is a blend of simulation and strategy, and players have the option to play on historic Earth or a randomly generated world, also allowing to choose its length, from short scenarios focusing on a single periods or the complete history of land vertebrates, from early tetrapods 360 million years ago to the appearance of intelligent species – the final objective of the game – with a single second representing 30 thousand years.

Few people know, but dinosaurs appeared during the early Permian and survived to this day on Africa.

Few people know, but dinosaurs appeared during the early Permian and survived to this day on Africa.

There are around 170 species, ranging from famous ones such as wooly mammoths and the Tyrannosaurus, as well as others – at the time of its release, that is – less known, such as Indricotherium and Ventastega. There are also intelligent species other than Homo sapiens, created by the developers in order to offer more variety and explore possibilities, such as Elephasapiens, an intelligent elephant, and the Saurosapiens, evolved from dinosaurs; so not only this game inspired me to the general idea of evolution, in a way it also my first ever contact with speculative evolution. There’s an in-game Bestiary, bringing informative texts about each creature, also explaining some of the decisions and exploration of ideas subtly introduced, such as synapsids and anapsids reptiles able to evolve into dinosaurs (in-game incentivized to be seen as analog species if an alternative path of evolution was taken) and the possibility of other animals being candidates to originate intelligent species.

And they STILL don’t get any pleasure from artistic pursuits.

And they STILL don’t get any pleasure from artistic pursuits.

The game is either played alone or against 5 opponents (computer or human controlled), but even on yourself the game is plenty challenging as continents move, climates change and the environments are altered and you need to evolve your creatures so they can keep up with the times – though not something easy, you can also go against it and see how long you can make an species survive, such as Pantylus enduring the Carboniferous all the way to the Cenozoic; it’s hard not to feel proud of the little guys. Each creature have an time period and specific ambient where they survive and feed better, thereof it’s imperative you take possession of the best feeding regions before your enemies do. When evolving new creatures you must allocate points that dictate how fast you evolved – determinate by how well you creature’s population are doing – , how much your feeding will improve and how fit for combat it is, offensively or defensively, this last point coming more into play in multiple players matches, as predator species are your main tools to maintain control of your territories and chase invaders away. As if it wasn’t enough the fight for survival among creatures, there are also natural disasters, causing mass extinctions and sometimes even altering the global climate to challenge you even more.

You’ll have to excuse the oddly outdated swamp-dwelling Diplodocus; At least it’s not dragging its tail.

You’ll have to excuse the oddly outdated swamp-dwelling Diplodocus; At least it’s not dragging its tail.

The game shipped with a Tree of Life poster, containing all the creatures of the game and the evolutionary lines, and a printed version of the Bestiary with higher-res versions of the creature’s graphics in all their 90’s 3D graphics glory. The Brazilian release only came with the poster (good grief), but it’s all good, to this day I keep it safe so one day I can frame it and put on a wall. The game manual, as per tradition of games released on that decade, contained additional information, in special the notes of designer Greg Costikyan regarding the decisions taken in the game’s development, such as the limitations of the time it was made forcing a rigorous selection of species that could offer a good variety of creatures and still create an evolutionary tree analogous to that of real life; all whilst fitting inside a CD-ROM.

Although with slow-paced playability – something that doesn’t attract as many people as first person shooters–, it’s to this day one of my all-time favorites, despite only able to run on Windows 98 and previous OS without the help of modifications. Before this game my knowledge about Earth’s past was limited to dinosaurs and what was taught at school like human history, so I’m happy I could get a hold of it when I did, and I’m thankful in all sincerity for those that were responsible for this project.

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Filed under Art, Multimedia

Friday Fellow: ‘Ladislau’s Flatworm’

ResearchBlogging.orgby Piter Kehoma Boll

Friday fellow is back!

After almost a year, I decided to go on with it. Actually, I interrupted it because of several other activities that were requiring my attention. Now let’s move on!

Today I will present to you another land planarian, and one I particularly like. Its binominal name is Obama ladislavii (formerly Geoplana ladislavii) and, as most land planarians, it does not have a popular name, although I suggest it to be ‘Ladislau’s Obama’ or ‘Ladislau’s Flatworm’. Now who is Ladislau?

Well, let’s first take a look at how this species was first described.

The Ladislau’s Flatworm was described in 1899 by the zoologist Ludwig von Graff in his famous monograph, “Monographie der Turbellarien”. Graff described it based on specimens sent to him from southern Brazil by the zoologist Hermann von Ihering, as well as on other specimens collected by the biologist Fritz Müller.

By the time Ihering and Müller were collecting specimens in Brazil, a botanist named Ladislau de Souza Mello Netto was the director of the Brazilian National Museum in Rio de Janeiro. He actually hired them as traveling naturalists, so we can say that he was the responsible for them being able to collect specimens in Brazil.

As a result, when describing this new planarian species, Graff decided to call it ladislavii in honor of Ladislau Netto. At least I think so! I did not find any reference to that, as Graff did not explain the etymology of the name in the description. However, whom else would ladislavii be referring to?

Now that we explained the name, it is time to talk about the worm itself.

Ladislau’s flatworm is found in southern Brazil’s states of Rio Grande do Sul and Santa Catarina and is easily recognized by its green color. The larger specimens can measure more than 10 cm in length and more than 1 cm in breadth while creeping, so it is a considerably large planarian for the local standards.

Obama ladislavii in all of its greenness. Photo by Piter K. Boll*

Obama ladislavii in all of its greenness. Photo by Piter K. Boll*

Most land planarians are found either in very well preserved ecosystems, for example, inside undisturbed forests, or in very well disturbed ecosystems, such as gardens and urban parks. Now we can find the Ladislau’s flatworm living very well both in a natural paradise in the middle of a dense forest as well as in that small garden beside a very busy street. How is that possible?

The life history of many land planarian species is completely unknown, so that we do not even know what they eat. They are recognized as important predators of other invertebrates, but that is not enough, as being a predator does not mean that you eat anything that moves, right?

Until recently, we knew very little about the Ladislau’s flatworm, but I started to study it along with other species in the last years and so now we at least have an idea of what it eats, and the answer is: Gastropods, i.e., slugs and snails!

We usually found gastropods in gardens, parks, plantations and everywhere humans plant something, so they are an available meal for the Ladislau’s flatworm. It feeds on many of those annoying little pests you may find in your garden, including the garden snail (Helix aspersa), the Asian trampsnail (Bradybaena similaris), and the marsh slug (Deroceras laeve).

Obama ladislavii and one of its snacks, the snail Bradybaena similaris

Obama ladislavii and one of its snacks, the snail Bradybaena similaris. Photo by Piter K. Boll*

The Ladislau’s flatworm can follow the slime trail left by the gastropod in order to find and capture it. The most efficient way for the planarian to subjugate the prey is by surrounding it with its body and using muscular power, not very different from what a constrictor snake does.

Considering its taste for those pests, the Ladislau’s flatworm seems to be a good item to have in your garden, right? Yes, but only if you live in southern Brazil. Exporting it to other areas can lead to catastrophic results, as the case you can read here.

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References:

Boll, P., & Leal-Zanchet, A. (2014). Predation on invasive land gastropods by a Neotropical land planarian Journal of Natural History, 1-12 DOI: 10.1080/00222933.2014.981312

Graff, L. v. 1899. Monographie der Turbellarien. II. Tricladida Terricola. Engelmann, Leipzig, 574 p.

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Filed under Behavior, Ecology, Friday Fellow, Zoology

Pooping to evolve: how feces allowed us to exist

by Piter Kehoma Boll

ResearchBlogging.orgBillions of years ago, when the first lifeforms appeared on Earth, our planet was very different from what it is today. Oxygen, so essential for our survival, was not present in the atmosphere.

Thanks to the appearance of the first photosynthetic bacteria, the so-called Cyanobacteria or blue-green algae, our atmosphere started to accumulate oxygen. As you may know, photosynthesis is a process by which plants and other photosynthetic organisms convert water and carbon dioxide into oxygen and organic compounds.

Oxygen is a very reactive element, so it can easily interact with other compounds and is great to burn organic matter to release energy. Without oxygen, heterotrophic life, such as animals, would not be able to use large quantities of energy and therefore would have never been able to achieve large size.

As you may also know, animals most likely appeared in the oceans and only much later conquered the land. However, oxygen produced by photosynthesis accumulates mainly in the atmosphere and not in the oceans. Today, only 1% of the global oxygen is found in the oceans, and it was even worse during the first million years of multicellular life. Do you know why?

The most primitive animals alive today are sponges, which are quite different from other animals. They usually have a hollow body with several pores, which function as tiny mouths through which water carrying small planktonic organisms and other organic matter is pulled inwards and later released by a large opening on the top of the body. So the main thing sponges do is mixing water and extracting a small amount of organic matter from the water column. Their feces, when returning to the water, are not very different in size from the organic matter they initially ingested.

Sponges ingest organic particles and release organic particles. They are not very efficient in removing organic matter from water.

Sponges ingest organic particles and release organic particles. They are not very efficient in removing organic matter from water.

Thus, in a sponge-only world, the water column was possibly always crowded with dissolved organic matter. This was a feast for bacteria, which are always eager to decompose organic matter and, while doing so, they consume large amounts of oxygen. Therefore, water with high amounts of organic matter increases bacterial activity and turns the environment anoxic, i.e., without oxygen. As a result, there was no oxygen available to allow animals to become large.

Despite not growing very much, animals were still evolving, of course, and eventually the bilaterian animals appeared. Bilaterian animals have a bilateral symmetry and, the most important feature in this story, a gut. It means they ingest food, digest it, process it and later eliminate the rests as… poop! In the gut, feces become compact as fecal pellets and sink much quickly to the bottom of the ocean, cleaning the water column from organic matter and drastically reducing bacterial activity. With no bacteria decomposing in the water column, the oxygen levels rapidly started to increase, allowing animals to grow and things like fish to evolve.

Bilaterian animals produce compact fecal pellets which sink to the bottom, cleaning the water column.

Bilaterian animals produce compact fecal pellets which sink to the bottom, cleaning the water column.

If animals had never started to poop, we most likely would have never been able to arise in this world. Long live the poop!

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References:

Holland, H. (2006). The oxygenation of the atmosphere and oceans. Philosophical Transactions of the Royal Society B: Biological Sciences, 361 (1470), 903-915 DOI: 10.1098/rstb.2006.1838

Turner, J. T. (2002). Zooplankton fecal pellets, marine snow and
sinking phytoplankton blooms. Aquatic Microbial Ecology, 27, 57-102

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Filed under Ecology, Evolution, Paleontology