#Non-Tetrapod Lobe-finned Fish

[taxonomytournament]

Taxonomy Tournament: Amphibians* Finale

Urodela. This order is made up of amphibians that have a tail, such as newts and salamanders, including the axolotl.

Non-Tetrapod Lobe-finned Fish. This class is made up of fishes whose front fins are fleshy and joined to the body by bones, these being lungfish and coelecanths.

*Non-Tetrapod Lobe-finned Fish are not Amphibians

[a-dinosaur-a-day]

I have a question for you that is tangentially related to some of your recent posts. I remember reading a while ago that the term "fish" is somewhat controversial for taxonomists because of how many animals are fish and (I think) that what are generally considered fish don't fit in a single clade without including all other tetrapods (and maybe also vertebrates) (on a related note, I'm pretty sure the same is true for trees but without the controversy). Do you know if I my memory is correct and, if so, where do you stand on the controversy. I'm assuming you'd be pro-"fish" as a term. Also very sorry if this doesn't make sense. I tried my best but I feel that it may still be confusing. Also have a great day! (And happy late/early birthday to your spouse! (you have one of those I think))

Hello! (Spouse's bday is Feb 12 :) so veeeery early and he's scared of turning 32 so)

so we have to do a little history of science here

"fish" is a term that existed before science, or at least, modern science. it basically meant "aquatic organism". it wasn't a relational term, so we didn't treat it like one

then Linnaeus, annoying taxonomist from whom we will never escape, decided that "fish" meant, specifically, certain types of aquatic vertebrates: Chondrichthyes, Actinopterygii, and Sarcopterygii without tetrapods

so, for most biologists for the past three hundred years, "fish" has meant Aquatic Non-Tetrapod Vertebrate

so the whole thing with "jellyfish" and "starfish" isn't really relevant to the discussion because they were already thrown out of the fish group to begin with

now, we are trying to use cladistics instead of Linnaeus bc linnaeus' system doesn't work for fossil organisms

which means we group organisms based on descent, not traits

which means tetrapods, which descended specifically from lobe-finned fish

are lobe-finned fish

so, we have the situation where whales were fish (pre linnaeus, aquatic organism) and then weren't (mammals aren't fish) and then are again (mammals are fish)

the people who say "fish aren't real" are ignoring that important middle step where scientists decided that fish was just a vertebrate term; they're acting like "jellyfish" and "starfish" are still considered fish when they haven't been for 300 years

so, yeah. I'm pro fish. much of tetrapod anatomy is only explicable when you remember we are fish. but, ultimately, I'm not going to correct people on that one

alternatively, we just start calling everything actinopterygiian or sarcopterygiian or chondrichthyan or whatever. I doubt people will get behind that though

yeah I wish the history of science was taught better bc a lot of these discussions would become sooooo much more streamlined

[sinosauropteryx--prima]

Life in the Devonian

(first row: Cladoselache, Titanichthys, Walliserops; second row: Tiktaalik, Dunkleosteus, Ichthyostega; third row: Jaekelopterus, Archaeopteris, Paleocharinus; fourth row: Gondwanascorpio, Ryniella)

Art by:

Walliserops - Richard A. Fortey (The lifestyles of the trilobites)

Cladoselache -Christian Darkin

Tiktaalik - Ntvtiko

Ichthyostega - Davide Bonadonna

Dunkleosteus - Robert Fabiani

Titanichthys - Mark Witton

Jaekelopterus - Dani Navarro

Archaeopteris - Annette Townsend

Gondwanascorpio - Ariel Milani Martine

Ryniella, Paleocharinus - Bizley Art

Welcome to the Age of Fish!

Whatever you‘re looking for, we have the right fish for you. May I interest you in some early shark-cousins like Cladoselache? Or maybe you prefer bony fish over cartilaginous ones. In that case you‘re in luck because they now come in two brand new varieties: The ray-finned fish and the lobe-finned fish. As you might have suspected, their fins work differently: Ray-finned fish have bony spines covered by skin, that form a fan-like fins. Today they make up almost 99 % of fish species and more than 50 % of all vertebrate species. So if you‘re picturing any type of fish right now, that is probably a ray-finned fish.

The only lobe-finned fish that are still around today are the coelacanths and lungfish, but during the Devonian they were much more common. They have fleshy fins that have an extra bone that separates the actual fin-part from the rest of the body.

But before I talk more about fins with extra bones, let‘s give the spotlight to the real stars of the Devonian: The Placoderms. The “armored fish“ got their name from the bony plates that cover their head. They had jaws (and were the first vertebrates to do so), but no real teeth. However, in many species their bony armor had self-sharpening edges at the mouth, that were used similar to teeth (and honestly, that sounds somehow more terrifying than actual teeth).

Although most of them were mid-sized, the biggest ones like Dunkleosteus and Titanichthys reached sizes similar to a modern white shark (4-6 m), maybe even bigger. Titanichthys is assumed to be a filter feeder, while Dunkleosteus was an active hunter marking the first time vertebrates took over the roles of apex predators.

Placoderms in general were pretty big on being the first vertebrates to do things: They were among the first to colonize the open ocean as well as freshwater (I don‘t spend enough time appreciating that water is not just water, but has tons of different habitats). They were also the first ones to have clasper-like structures, which is the fish version of a penis. With that they were able to have internal fertilization or, as the non-scientist call it, sex. Before the placoderms came around, vertebrates weren‘t doing that. Related to that, placoderms are the oldest known case of an animal giving live birth.

One more cool thing about placoderms is that they are the oldest known case of fossilized pigment in vertebrates. Personally, I absolutely love everything that has to do with coloration in prehistoric animals, so I will bring it up as often as I possibly can. This particular fish supposedly had a silvery iridescent belly and a red-ish back. Not only is this cool, because that‘s a very pretty fish, but also because it might hint towards placoderms having color vision.

Since the placoderms were terrorizing the oceans, some of those lobe-finned fish I talked about had quite a bit of motivation to get away from them. This is where those extra bones I mentioned came in handy, because they evolved into leg-like structures. Air bladders, which were originally used for buoyancy, were repurposed into lungs for breathing. This new group of vertebrate was able to invade the land. Animals like Ichthyostega and Tiktaalik were among the very first tetrapods (that translates to “four legs“), a group that today includes amphibians, reptiles, birds and mammals (that‘s us!).

The tetrapods were however not the first life on land, in fact they were pretty late to the party. By this time there were already many plants on land, including the very first trees like Archeopteris, the very first insects, scorpions and other arachnids like Paleocharinus (which is not a true spider, but a close cousin. Reading about them did however gave me a nightmare, so it‘s close enough to spiders to trigger my arachnophobia).

The last mention should probably go to Jaekelopterus, the biggest eurypterid (“sea scorpion“), and therefore biggest arthropod ever, with a size of over 2.5 m. Just imagine a fucking 2.5 me long bug. I kinda hate it. And I‘m impressed.

[abyssalzones]

favorite deep sea creature?

sorry this one took so long to answer. it's also very long. but I feel like you knew what you were getting into when you asked tumblr user "abyssalzones" what his favorite deep sea creature is.

now immediately my mind jumped to coelacanths because they're among my favorite fish Ever for a multitude of reasons, such as (but not limited to):

-their mystique (their fossilized ancestors were initially discovered in the 19th century, and due to their illusive nature were thought to have gone extinct at the end of the Cretaceous period until one was found alive by an unknown(?) fisherman off the coast of South Africa, and from there the discovery was accredited to museum curator Marjorie Courtenay-Latimar who spotted it in the day's catch. however it's worth mentioning fishermen in the eastern South African region may have known about the species before then. kind of a 'who can say if it wasn't written down' situation.)

-their beautiful blueness (others have waxed poetic about their appearance more skillfully than I, but just look at this guy. wow. albeit I have to wonder if how blue they appear is very dependent on lighting but whatever he's beautiful)

-and, finally, their importance as lobe-finned fish! (the two extant species of Coelacanth today- alongside lungfish, who are also incredibly cool- hold a unique position in taxonomy and evolutionary history as the only living non-tetrapod sarcopterygians that we know of ^_^ they used to be much more dominant as freshwater predators, but then the great dying came along and they suffered a significant decline. so, essentially, these guys are survivors! ...if you felt it necessary to frame it as such. and "sarcopterygian" more specifically describes them as belonging to the clade 'Sarcopterygii', which classifies them as lobe-finned bony fish. this contrasts the other clade of bony fish, Actinopterygii, which describes ray-finned bony fish. in essence, they are the great-great-great-great-ad-nauseum-grandparents of all tetrapods! very very important animals from a grander biological perspective.)

...however, after typing all of this out, I realize this is a little bit of a cop-out. Coelacanths, as cool as they are, are actually not the deepest of deep-sea fish. It's difficult to get the exact numbers on their whereabouts as, previously stated, they're pretty elusive guys, but generally during the daytime they're found about 100-500 meters deep, resting in caves and saving their energy for nocturnal reef-feeding. apparently they've been found to migrate deeper as well, but it still feels a little disingenuous (to me) to say that they're truly deep-sea animals.

...so if I want to live up to my username, I need to take you on a journey. to the abyssal zone. where you will find some truly terrifying, near-alien creatures, straight from the pits of Dante Alighieri's visions of hell, or Hieronymus Bosch's bizarre garden of earthly delights...!

no, not that guy! get him out of here. shoo.

Instead we're going to be talking about his big brother. his... very, very big brother.

okay so chances are you've seen this photo before, it circulates quite a bit online as "BIG FUCKING SCARY THING IN THE OCEAN" and it's pretty apparent why, but I'm incredibly fond of "Scary fucking thing in the ocean" in general, and as such I think this guy is delightful. I debated on picking a couple of different, lesser-known species from the abyssal-hadal range (such as various arctic amphipods), but if I'm honest I have a soft spot for cephalopods. typical, typical I know, I should be ashamed, but in this case I can safely say the Bigfin squid (genus Magnapinna) is anything but "typical".

oh, sure, there's a level of wonder healthily exacerbated by the rarity of sightings- but that's all we have! sightings and footage! well, that and washed-up corpses dating back to 1883, all being damaged juveniles that were never properly collected. even so, their significance and oddity isn't really made apparent until you see their adult form, which first came to science's attention properly in 2001 when some very grainy footage was captured by an oil drilling ship, the Milennium Explorer, in the gulf of Mexico.

he's shy.

I say "first came to science's attention" because the Bigfin had actually been recorded prior, all the way back to 1998, but no one had really gotten up out of their chair and started dancing around at the realization of holy shit, what is this thing? and from there further work was done on properly identifying and analyzing the species based on footage.

however... it's still just footage. there has not yet been a captured live specimen, nor a well-preserved cadaver, or... really anything to tell us more about this mysterious cephalopod, other than what we can tell visually and geographically. we know it sure looks distinctive compared to various species of squid (check out the elbows on that thing), we know the largest adult specimens seem to be about 25 feet long (with estimates going up to 40 feet), and we know it might be the deepest-occurring genus of squid (we've had sightings as deep as 6,212 meters below the surface- well into the hadal zone, actually, not just the abyssopelagic), but in terms of behavior? breeding? feeding habits?? there are a lot of unanswered questions. and that's not to discredit any legitimate scientific analysis, past or present, of the bigfin, but moreso to stress that it's a very mysterious creature we don't have much data on.

I think just in general, my favorite deep-sea creatures (and this extends to just about any species, sea-dwelling or otherwise) are those that do a very thorough job of not being found. I am driven by a deep curiosity into whatever is so weird and leads such an unimaginable life to us humans that it eludes the microscope or the scalpel time and time again.

oh, and bigfin squids kind of remind me of the alien controllers that fly around your head during the xen levels in half-life. so there's that as well.

[sciencespies]

Bizarre Coelacanth hasn't spent 65 million years unchanged after all, its genome reveals

https://sciencespies.com/nature/bizarre-coelacanth-hasnt-spent-65-million-years-unchanged-after-all-its-genome-reveals/

Bizarre Coelacanth hasn't spent 65 million years unchanged after all, its genome reveals

In 1938, a living relic, thought 65 million years long extinct, was accidentally captured in a trawl net off the coast of South Africa.

The 2-metre (6.5-foot) long coelacanth (Latimeria chalumnae) turned out to be one of our closest fish relatives – looking largely unchanged since its most recent appearance in the fossil record back from the time of non-avian dinosaurs.

Now new genetic evidence shows this deep-sea predator has undergone hidden, but widespread evolution at a genetic level – by hijacking genes from other species.

While searching genetic databases for the ancestral version of a human gene involved in gene regulation, CGGBP1, University of Toronto molecular geneticist Isaac Yellan unexpectedly found coelacanth strangely has many variations of this gene.

Even more unusually, these different variations of the CGGBP genes didn’t all share a common ancestor with each other. This suggests that at some points around 10 million years ago, 62 of these genes were swiped by the coelacanth from other, unrelated species – through horizontal gene transfer.

These genes, with their ability to ‘jump’ around and even between genomes a bit like viruses, are known as transposons.

If they happen to jump into the right place in the genome, cellular machinery will copy them just like any other gene. But they can also jump into the wrong place, where they can be harmful and so are thought of as parasitic.

Occasionally though, they can end up in a position that’s useful to their host species and end up losing their ability to jump around but are conserved within their new place in the genome, which is what seems to have happened in the coelacanth, several times over.

“Horizontal gene transfer fuzzies up the picture of where the transposons came from but we know from other species that it can occur via parasitism,” said Yellan. “The most likely explanation is that they were introduced multiple times throughout evolutionary history.”

While it’s common to find transposons like these in many species, it’s unusual to find so many.

Test tube experiments and computer modelling demonstrated at least eight of the proteins that these genes code for bind to distinct repeated sequences of DNA, suggesting that – like the human version – they are involved in gene regulation. Some of them are only expressed in specific tissues.

“We don’t know what these 62 genes are doing, but many of them encode DNA binding proteins and probably have a role in gene regulation, where even subtle changes are important in evolution,” explained University of Toronto molecular geneticist Tim Hughes.

Coelacanth have leg-like lobed fins and are more closely related to us and our closest fishy relatives, the lungfish, than other types of fish. Our very distant shared ancestor means the coelacanth’s genome has the potential to help us unravel many mysteries about our own evolution.

Unfortunately, these fish are rarely seen and endangered, so opportunities to study them are limited. But the information we have from them is already proving fruitful.

A recent study on their genes suggests our bitter receptors may have roles beyond protecting us from toxic substances, like metabolic regulation and hormone sensing. Now coelacanth genes have demonstrated transposons potentially play a larger role than we realise in tetrapod evolution.

“Our findings provide a rather striking example of this phenomenon of transposons contributing to the host genome,” said Hughe.

This research was published in Molecular Biology and Evolution.

#Nature

[jurassicsunsets]

why do tetrapod limbs have 2 bones in their "outer" halves (radius/ulna & fibula/tibia)--is it just an evolutionary quirk or does it have some advantage? (I had originally thought it was to allow rotation but since most tetrapods cant rotate their limbs like mammals im guessing thats wrong)

As far as I’m aware, it’s an evolutionary quirk. It’s an arrangement that’s present even in early non-tetrapod lobe-finned fish that are closely related to our ancestors:

[universeinform-blog]

Exquisitely preserved fossil deposit a window on early life on land

New Post has been published on https://universeinform.com/2017/03/19/exquisitely-preserved-fossil-deposit-a-window-on-early-life-on-land/

Exquisitely preserved fossil deposit a window on early life on land

How existence made the move onto land is one of the large questions for palaeobiologists. The physiological demanding situations had been huge and affected maximum facets of existence. Organisms had to adapt how they received water (and averted themselves drying out), the way to attain vitamins, the way to change glasses with the surroundings, the way to support and pass a frame without water buoyancy, not to mention reproducing out of the water. Existence doesn’t have a grand plan, and terrestrialization (as the method is understood) become a messy, incremental procedure, with one-of-a-kind organisms adapting to life on land at extraordinary places. It’s a piece of going tenting with a gang of pals. There might be the eager, pioneering kids who want to get there early, installation camp and solve any problems

Then there are the overdue-comers, who roll up with the beer while most of the tough paintings have been accomplished. The popular picture of a lobe-finned fish lolloping up a seashore to overcome the land is attractive, however, there are lots that befell on land before the tetrapods joined the celebration.

There are clues to the earliest degrees inside the timeline of the flow onto land. Microbial mats had probably been sliming the margins of water bodies for the reason that Precambrian, extra than 500 million years in the past. Fossil soils (referred to as palaeosols) from about 460 million years ago propose that natural rely was being deposited and then recycled by microbes, arthropods have been burrowing, and clumps of plants had been even stabilizing mature soils (but without a direct evidence of the flora themselves). Microfossils preserved in near-shore sediments additionally inform us that vegetation had been already producing spores (an adaptation to life on land), and dispersed plant tissues show that early land plants had already developed by that factor. We are very fortunate to have a photograph of the earliest ecosystems on land from just over 4 hundred million years in the past, in an exquisitely preserved deposit known as the Rhynie Chert, from Rhynie, a village in Aberdeenshire. A scientific assembly final week on the Royal Society in London introduced collectively a global network of Rhynie Chert researchers to share their collective information, at the centenary of the first scientific e-book at the Chert via palaeobotanists Kidston and Lang.

4 hundred million years ago, Scotland was sitting just south of the Equator, and the upland place that has become The Rhine might have seemed similar to these days’ Yellowstone Park. Warm springs wealthy in minerals could have ruled the landscape. We recognize from contemporary equivalents that the vent swimming pools themselves might be too Hot and alkaline to harbor and hold existence, but as you move far from the events, out closer to cooler,

Much less alkaline (however nonetheless inhospitable) geothermal wetlands, you notice a sequence of various organisms making the exceptional of an extreme habitat. The first rate component about the geothermal putting at Rhynie is that the precipitation of silica from the hot spring water hastily preserved organisms in lifestyles role and with the mobile element.

Collecting Exquisitely Realistic Doll Creations

Several manufacturers have ventured into producing dolls which have practical capabilities. Each of them had showcased an array of first-rate excellent creations that are cautiously handcrafted and painted. But those dolls aren’t often supposed for children and those are focused to the demands of clients with exceptional flavor. In general individuals of their Thirties and above have the fascination of gathering dolls for aesthetic purposes and for the affection of the craft. One toy producer that has been regarded as its interest in information and use of nice materials is the Ashton-Drake.

Ashton-Drake galleries have a myriad of serious or doll collections for individuals who need to begin their collection of practical masterpieces. They have the selection of doll subject matters inclusive of reborn dolls, animal toddler dolls, nonsecular characters, cultural dolls, fashion and bride dolls, and even plush dolls. One of the most modern additions to the fashion and bride collection is the restricted version Kate Middleton commemorative porcelain bride doll. The price variety for Ashton-Drake’s dolls begins from $ forty to $230. The dolls length also can range from 3 inches to 21 inches.

One also can pick out the type of materials used for the dolls. Ashton-Drake galleries online provide vinyl resin and porcelain dolls. Despite the fact that, the vinyl material offers a delicately human skin like texture and the information spent on portray even at the fingers are realistic. They have got doll strains that provide a wide range of designs which might be amazingly real looking. A number of their famous doll strains are So Actually Actual, Tiny Miracles, Heavenly Handfuls, Emmy’s International, Emily Peculiar, and Delilah Noir. So Definitely Actual caters life like new child infant dolls truly looks like a Real respiratory child. The poseable style is priced better at around $230 compared to the alternative non-poseable styles in this collection.

Ashton-Drake has been One of the most successful doll makers which have been production an extensive type of high-value collectible dolls considering 1985. Today, They’ve also come up with collectible and cuddly plush dolls. Nonetheless, within the essence of being sensible, their animal dolls have the realistic bushy enchantment, especially with their canine puppy variety. There are the plush koala, panda, and lion dolls which are perfectly posed in their browsing positions. However, They have a luxurious teddy bear collection that’s sporting Elvis Presley’s famous concert clothes and add-ons. The lush series is also perfect for young kids instead of giving them the delicate vinyl and porcelain alternatives.

Preserving Food Using Citric Acid

Nowadays, everybody is making an attempt to shed pounds. A common complaint is that its miles too high priced to hold culmination and vegetables at your private home. The shelf existence is so quick that the product regularly is going awful before you get a danger to eat it. Then you have to throw it away and purchase new stuff, however, it is discouraging and might regularly feel like throwing away money. The majority just head to the junk food aisle and choose bad snacks that sell weight advantage and heart issues in place of gaining knowledge of approaches to keep the healthy, fresh meals.

So how are you going to hold those ‘farmers marketplace’ ingredients so that you can maintain them reachable for a healthy lifestyle? One famous technique is ‘canning’. Canning meals is a great way to keep your products for a long time, well organized to your meals cabinet. There are two approaches to can: The boiling water approach and the stress canning technique. Both are secure, and the approach used will rely on what meals you are canning. Low acid meals can be preserved through strain cooking because of their pH levels (underneath 4.6). Higher acid foods (approximately

Need to be preserved the use of the boiling water technique. Here’s where it receives elaborate. If you have a meal this is close to a 4.6 pH stage, you may need to feature acid to it. The purpose high acid meals may be preserved surely by way of using the boiling water technique, is because they’ve enough acid so that Clostridium botulinum spores can not develop they’re harmful, regularly lethal, toxic. ingredients like tomato and figs want extra acid in order that the shelf lifestyles can maintain surroundings with an out harmful boom on the meals.preserved synonym

I’ve observed citric acid to be the quality additive to save you microorganism growth, Each in canning and easy preservation of culmination, veggies, and different ingredients. Whether or not or not you opt to can is inappropriate. this is simply one of the methods to maintain your meals brisker, for longer. In case you are simply trying to add days to the shelf lifestyles of your end result or vegetables, you could upload the citric acid at once, not wanting any special sort of processing or cans to preserve the meals fresh.

Many stores and websites sell citric acid to the average customer. In many instances, it’s far packaged under the call ‘bitter salt’. It can come packaged searching like a spice in a shaking box, or by means of the bag. Some companies promote it by using the pound, so you can get the most important bang to your greenback. Shopping for through the pound will prevent cash and allow you to use it for numerous things. Do your research and you will discover citric acid has more than one advantages, a long way beyond meals maintenance.

Life Hacks For The Modern Traveler

Travelling is always a nightmare for plenty. As a modern day visitor, one has to realize a way to travel peacefully to get a nice vacation. This means one should have the understanding of a way to % the baggage without getting troubled with it making your mobility on hand. Gadgets help us lots, and for some of us it’s a need to carry around, but what takes place whilst the internet connection is limited or isn’t even there? So right here I have some pinnacle lifestyles hacks for you to help you in Journeying effortlessly whether or not you travel by land, sea or air.

Roll Garments

In preference to folding your Garments, roll then into lengthy tubes. No longer most effective will this prevent creasing, but you may find you may suit a whole lot greater into your suitcase, as rolled up Clothes absorb much less room.

Pro Tip: Socks may be rolled into balls and then located interior shoes for extra space saving.

Digitise

Create digital backups of all the vital files you will need in your trip, such as passports, any booking confirmations, boarding passes, and so on. so that you’re covered in the event of loss or robbery.

Adaptors

P.C  one multi-fee adapter for all gadgets In place of numerous specific chargers. In case you’re Visiting overseas, percent an extension cord so that you can electricity more than one matters right away the use of one overseas plug adaptor.

Pro Tip: Maximum contemporary Tv’s have USB ports in the returned, best In case you forget about your charger plug.

  Passwords

before you head off, use Foursquare to find wi-fi passwords for all the exclusive spots you discover. People continually list passwords on journey websites like this, making your existence a good deal easier when you arrive.

Reserving

when you’re reserving online, whether or not it is flight, cruise, lodge or something else, clear your browser cache or use an anonymous browser window. booking sites will frequently improve their prices in the event that they recognize you’ve been there before.

Credit score Card

In case you’re Visiting across the world, or you’ll be some distance from home for an extended period, name your Credit score card corporation and allow them to recognize. This manner they might not think your card has been stolen and won’t cancel it on you.

If you follow these suggestions, you can without difficulty make via your Traveling hassles and revel in your holiday peacefully.