X-ray microtomography 3D model of a bioeroded limestone pebble given to me by a friend who wanted to know what the holes were. Not technically art but I think it looks cool.
I identified 4 distinct types of borings (ichnotaxa) in this 3-cm pebble:
Entobia cf. cretacea (white): typical sponge borings, composed of interconnected chambers and exploratory threads; by far the dominant ichnotaxon in the sample (97% of bioeroded volume).
Caulostrepsis taeniola (blue): U-shaped borings made by polychaete worms (e.g. spionids).
Unnamed Caulostrepsis ichnospecies (cyan): long and tightly U-shaped borings, possibly also made by polychaete worms.
Trypanites solitarius (green): simple unbranched borings that can be produced by many different organisms (polychaetes, bryozoans, phoronids).
(A-B) Full sample. (A) External view. (B) Virtual mould of the borings. (C-G) Virtual moulds of individual borings. (C-E) Caulostrepsis taeniola (note the variability in size). (F) Caulostrepsis unnamed ichnospecies. (G) Trypanites solitarius.
Experiments with limestone bricks show that bioerosion comparable in nature and extent to the one showcased here can develop after 3-4 years (Färber et al. 2016), providing a rough estimate of the time elapsed between this rock fragment first being exposed and it washing onto the shore where my friend picked it up.
This archival image, snapped circa 1899, depicts paleoartist Charles Knight working on a scale model of the dinosaur Stegosaurus. In life, this species could measure 28 ft (8.5 m) long and weigh about 6,000 lbs (2,720 kg). But when this animal was discovered, paleontologists were surprised to find that its skull—and brain—were disproportionately small. In fact, some scientists thought this massive herbivore must have had a “second brain” near its hips that controlled the back half of its body. Turns out, Stegosaurus did manage with just one relatively small brain.
the infamous ‘last sighting of a barbary lion in the wild’ photo taken by marcelin flandrin (1925) haunts me to my core. there’s something so achingly poetic about it.
New, publicly available platform for analysing the 3D nanostructure of mitochondrial membranes – the convolutions called cristae – in unprecedented detail and in the context of the cell
Age: 303-306 million years ago, Carboniferous Period
Nine animals are crowded into this photograph. A single sea urchin, now crushed, was the home for a neighborhood of life.
The other members of the community, besides the sea urchin, are bryozoans and brachiopods. Bryozoans are microscopic animals that live together in colonies and build lacy skeletons (marked in blue in the map on the upper right). Brachiopods are soft animals that live inside a pair of shells (marked in green).
These fossils are the oldest evidence of community-building between sea urchins and other animals.
When these bryozoans and brachiopods were young, they floated in the ocean. When it was time to change into an adult, they settled on the spines of a sea urchin. They stayed there for the rest of their lives, filtering food out of the water around them.
Is there a benefit to these communities? The tiny hitchhikers probably didn’t benefit the sea urchin at all, but they didn’t hurt the sea urchin, either.
In contrast, sea urchin spines were an ideal home for the smaller animals. The hitchhikers, unable to move on their own, could find new food sources on the back of a sea urchin. The spines provided protection that they could not provide for themselves. Finally, hard spines made a better home than the alternative - soft mud that could bury a small, immobile animal alive.
Specimen Number:TMM 1967TX61
Sources:
Schneider, Chris L. “Hitchhiking on Pennsylvanian echinoids: Epibionts on Archaeocidaris.” Palaios 18(2003):435-444.
