It's no secret that nerds love dinosaurs. While body art of a living dinosaur is likely to look cartoonish, fossils have a certain scientific air to them. A fossil tattoo should have a subtle, classy color scheme. Fossil designs are ideal for those who want to avoid a garish, multi-colored tattoo.

Hint: Think beyond Triceratops. Consider a tattoo featuring more obscure prehistoric creatures, such as trilobites or ammonites.

Oh, why didn't I consult the experts before I branded myself for life as a total amateur?!

But is my tattoo a fanciful picture of a fossil with floral decorations, or a scene set in the Cretaceous of a (relatively) freshly decomposed triceratops in a field of flowers? What do you think?

LOLCATS!

An article published recently in Nature explored the routes of diversification taken by early mammals, but particularly caught my attention due to its excellent mammalian family tree.

Reprinted by permission from Macmillan
Publishers Ltd: Nature, 450, 1011-1019, 2007.

Only those lineages extending to the far right of the diagram have survived to the modern day. In the smaller inset the thickness of the bands for each group illustrate how common it was in various time periods. You can see the multituberculates, notable for their unusual tooth anatomy, were very common until the early Paleocene. Historically these were the dominant group of mammals, existing in the largest numbers for the longest time--and now long extinct. Their contemporaries, the spalacotheroids and eutriconodonts, were successful in the early Cretaceous but were in decline by the end of that period. At the root of the tree the groups shown in blue are mammaliaforms--not true mammals yet, but very similar. This group first appeared in the Jurassic and did not survive the Cretaceous. The Cretaceous ended with a global extinction that eradicated the dinosaurs, and many stem-mammals suffered the same fate. Others lingered into the Paleocene only to become extinct, possibly outcompeted in the rapid radiation of the therians.

Since the mammaliaforms evolved from egg-laying therapsids and the monotremes still preserve egg-laying, it's likely that the early mammals reproduced by laying eggs up until node 3 on the diagram. The skeletal structure of the multituberculates suggests that they bore immature live young similar to those of the marsupials. Since the monotremes produce milk, but secrete it through pores, it's likely that nipples evolved at node 3 or sometime after. This may have happened as late as the divergence of the eutherians and marsupials, but probably came earlier. Some researchers think that milk secretion originally evolved as a means of hydrating the thin, leathery shells of basal mammals' eggs, and was only secondarily used as a means of feeding hatchlings. With viviparity there would be a strong selective drive towards formation of a nipple to more efficiently feed the young. Evidence for this hypothesis will be found if it is discovered that monotremes secrete milk to coat their eggs.

The mammals have been furry since their beginning. The first fur preserved in the fossil record belongs to Castorocauda, a Jurassic mammaliaform with a resemblance to modern otters or beavers. This animal had a double-layered coat, with an undercoat and longer guard hairs. It is likely that fur evolved long before Castorocauda, and might pre-date the mammaliaforms. Unfortunately integument does not often leave traces in fossils, so most of the time we see no traces of fur, feathers, or scales.

We tend to think of extinct groups as more "primitive" than extant groups, but the mammals radiated rapidly and many niches occupied today were occupied by now-extinct forms in the past. The next diagram shows some of the niches available and how they have been filled at various times. The presence of a gliding mammaliaform in the Jurassic is especially interesting.

Reprinted by permission from Macmillan
Publishers Ltd: Nature, 450, 1011-1019, 2007.

Currently the information is more complete for Jurassic (more ancient!) species than Cretaceous, but this will change with new fossil discoveries. In the past twenty years we have about doubled the number of Mesozoic mammal genera known, and characterization of these groups has vastly improved.

The tree of life is rather like a dense bush, on which we see the outer foliage, but there is much more beneath the surface if only we will look.

Here's the article: http://news.nationalgeographic.com/news/2008/02/080205-anthropocene.html

My belief is that we can not reverse what we have done. A catastrophic solution is the only one; destroy all and start anew. Depressing? Not really. Just inevitable. As Jan Zalaseiwicz, one of the scientists cited in the article said, "the Anthropocene will appear about as suddenly as [the transition] triggered by the meteorite impact at the end of the Cretaceous" 65.5 million years ago, when the dinosaurs became extinct."

I still believe in personally striving to make as gentle of an impact as possible while I'm on this planet, but in the end I don't believe it will matter. We've done too much damage and we are too far away from humanity accepting its responsibility. There are still people who insist that humans have not altered global weather, or that non-organic agricultural methods are not that damaging, or that the death of some obscure species doesn't matter in the big picture.

Despite all this, I don't live my life under a cloud of doom and gloom. I have my little slice of paradise and I will do what I can to keep it healthy and that makes me very very happy. Those of us who believe in sustainability and who accept our responsibility as being a part of this planet and not rulers of it, will be the survivors, if there are any. If not, I'll at least know that I did my best.