# Most recently developed animal family **URL:** \ **Category:** Factual Questions\ **Created:** [September 30, 2015, 12:16am UTC](https://boards.straightdope.com/t/most-recently-developed-animal-family/732998 "2015-09-30T00:16:50Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Raygun99](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@Raygun99](https://boards.straightdope.com/u/Raygun99)\ **Post date:** [September 30, 2015, 12:16am UTC](https://boards.straightdope.com/t/most-recently-developed-animal-family/732998/1 "2015-09-30T00:16:50Z")
A question my daughter asked at the dinner table tonight got me wondering - is it known what the most recently developed or evolved family in the animal kingdom is? In other words, what group of species is the newest in the evolutionary record (\*\*not \*\*most recently discovered) that we can separate out? I realize that taxonomy is a mix of art and science, but I feel like there should be some sort of answer about what the “newest” animals are. ---
**Author:** ![steatopygia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steatopygia/32/3132_2.png) [@steatopygia](https://boards.straightdope.com/u/steatopygia)\ **Post date:** [September 30, 2015, 5:30am UTC](https://boards.straightdope.com/t/most-recently-developed-animal-family/732998/2 "2015-09-30T05:30:42Z")
[“some sort of answer”](http://www.bbc.co.uk/nature/20425468) BBC Nature article ---
**Author:** ![bordelond](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bordelond/32/150_2.png) [@bordelond](https://boards.straightdope.com/u/bordelond)\ **Post date:** [September 30, 2015, 4:23pm UTC](https://boards.straightdope.com/t/most-recently-developed-animal-family/732998/3 "2015-09-30T16:23:56Z")
> [@Raygun99](#): > > … is it known what the most recently developed or evolved family in the animal kingdom is? In other words, what group of species is the newest in the evolutionary record (\*\*not \*\*most recently discovered) that we can separate out? I have just started to research this basically by brute force, coming up with educated guesses on what might be the most recent families – then looking it up to see how recent they are thought to be. So far, I have checked the families _Hominidae_ (humans & great apes) and _Thylacinidae_ (the now-extinct Tasmanian wolves). Both seem to have come about at the beginning of the Miocene epoch (~23 M years ago). Seems like something should be newer that that. I was hoping something on a biologically isolated island like Tasmania or Madagascar would be a good bet – still looking. Maybe the Galapagos? If you’re counting plants, this could be a lot tougher to determine. Let alone invertebrates with short generational times. Hmmm. The question is a very good one, but seems hard to approach. EDIT: Ah, I see you are NOT counting plants – I could have read the question more thoroughly 😃 ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [September 30, 2015, 5:59pm UTC](https://boards.straightdope.com/t/most-recently-developed-animal-family/732998/4 "2015-09-30T17:59:33Z")
Just to be clear, you’re looking for the newest Family, in the technical taxonomic sense (a group smaller than an Order and bigger than a Genus)? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 30, 2015, 6:10pm UTC](https://boards.straightdope.com/t/most-recently-developed-animal-family/732998/5 "2015-09-30T18:10:22Z")
Not an animal, and not the record holder, but it’s interesting to note that the [poaceae](https://en.wikipedia.org/wiki/Poaceae#Evolution), or grasses, are probably only about 66 million years old. Pretty impressive, for a family that’s now so incredibly widespread and successful. ---
**Author:** ![Raygun99](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@Raygun99](https://boards.straightdope.com/u/Raygun99)\ **Post date:** [September 30, 2015, 6:14pm UTC](https://boards.straightdope.com/t/most-recently-developed-animal-family/732998/6 "2015-09-30T18:14:56Z")
Right. I’m thinking about how (for example) hippos and ceteans split apart at some point in the recent past, and what would be the most recent observable example of that. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [September 30, 2015, 6:46pm UTC](https://boards.straightdope.com/t/most-recently-developed-animal-family/732998/7 "2015-09-30T18:46:43Z")
It’s probably not going to be anything you’ve ever heard of. Here’s a recent [phylogeny of the mammals.](http://gregladen.com/wordpress/wp-content/graphics/mammal_tree_lg.jpg) Eyeballing it, the shortest branch seems to be between the pygmy right while (Neobalaenidae) and the other baleen whales (Balaeaidae). There are other short (recent) branches between obscure families of bats and marsupials. This depends, however, on what you call a family, which is quite arbitrary. Some taxonomists would use the evidence for a recent split to merge two separate families.