Tag Archive: Fossil friday

A 3.4 billion-year-old snapshot – Fossil Friday

There are amazing things to learn in the world of palaentology and archaeology and then there is this. Things that just blow it off. Indeed, in this week’s Fossil Friday we’ll be discussing about a 3.4 billion-year-old fossil. One that dates back to the times when Life appeared on Earth. And we’re not talking about some old finding, no, no, we’re talking about a discovery that was published this week.

photograph of fossil microbial mat

Photograph of the facies of the studied rock formation. On the close up on the right, thin sheets (laminations) can be observered (taken from Duda et al.).

These precise fossils are called stromatoliths, (more…)

The newest addition to our family – Fossil Friday

It is quite rare that we can add a new member to the Homo family, but it is what happened last year. Homo naledi, a long lost cousin of our species, has been added to the already complex family tree of the genus Homo. At Sci&Fi, we just wished these other humans were still alive, it would be such a fantastic world to have a mirror of our own humanity in modern times. Who knows how History would have unfolded? But let us not go off topic…

Homo naledi, assemblage of skeletal remains (taken from Berget et al.)

More than 15 000 bone pieces of, at least, 15 individuals, (more…)

Ancestral hair – Fossil Friday

Fossil of Spinolestes

Fossil remain of the Spinolestes xenarthrosus

Here is the Spinolestes xenarthrosus, or the fur ball as it has been nicknamed by the media. But it does not do it justice because this early mammal is the oldest evidence for a lot of features. While it is hard to appreciate it in this photo, it contained one of the basic elements that constitute modern mammals, hairs. Indeed, its skin and fur closely resembles modern mammals, nothing out of the extraordinary if it wasn’t for the fact that is 125 Millions of years!
There are a couple details that are interesting here about his animal. (more…)

Unnoticeable cooperation – Fossil Friday

There are discoveries that await to be made. In 2012, an astonishing discovery was made on a 453 to 458 Million years old slab of rock that had been sitting in a museum for already over a century. It was discovered that a colony of a species of prehistoric plankton was full of connections between the individual living spaces.  A feature that is either unique to this species or has also gone unnoticed in other sister species.
Graptolite specimen - Dicranograptus aff. ramosus

What you see is an example of graptolites. It is a word of greek origin meaning “written rock”. Graptolites are a class of extinct marine animals (a kind of plankton actually). They have the particularity of living in colonies and of building their own dwelling structure/housing complex which is called a rhabdosome, this is the part that is circled on the picture above. Rhabdosomes are mostly what is left of graptolites since their soft bodies do not fossilize well. Rhabdosomes contain hundreds of individual tubes/personal houses called thecae.

Rhabdosome are actually what have been used to tell different species apart. Indeed, they can be very varied from a single tube to complex branching or patterned structures depending on the species. Equally, depending on the species the rhabdosomes could have been attached to the ocean floor, free floating or attachable to sea weed etc.

The species here is thought to be Dicranograptus ramosus and there was an additional feature that had been overlooked for the century the slab of rock had been exposed. It was found that there were connections between the theca. It turns out that there actually are two types of connections and that they vary across  the colony. There are these ‘Hourglass’ and ‘Strap-like’ connections.
Graptolite colony with emphasis on network connecting theca

The image above emphasises the contours of these connections. They might be indicative that different type of individuals were inhabiting the colony and therefore that there might have been a division of labour within it. The thecae being all the same, it is thought to not represent sexual differences (dimorphism).

Could you imagine how many more discoveries are waiting to be made on fossils neatly put away on shelves or even exposed to the public?
Adrien for Sci&Fi, over and out.

References:
Zalasiewicz, J.A. et al. (2013) Polymorphic organization in a planktonic graptoloid (Hemichordata: Pterobranchia) colony of Late Ordovician age. Geological magazine. (PDF)
Encyclopedia.com, Graptolithina.
Eurekalet. 2012. Prehistoric builders reveal trade secrets.

Visual credits:
Graptolite Specimen, Paul Witney, BGS, (c) NERC 2012
Rhabdopleura compacta, Dr. Atsuko Sato, University of Oxford.

Oldest plant fossil – Fossil friday

Oldest plant fossils - Liverwort cryptospores
You are looking at the oldest plant remains scientists have ever found. These are spores (cryptospores to be precise) which are no bigger than 40 µm (micrometers) from at least five different species including an unknown one (h). They dated the rocks containing them and found their age to be 471 to 473 millions of years old! Although none of the species that produced these spores are alive today, their descendants still are however. They form a clade of primitive plants (more…)