#eptatretus

[herpsandbirds]

can I hauve a hagfish

Hagfish:

Yes, here, have a hagfish, for you...

Pacific Hagfish (Eptatretus stoutii), family Myxinidae, order Myxiniformes, found on the ocean floor in deep parts of the Pacific Ocean

Jawless fish.

photos: Mark Conlin, Linda Snook | NOAA, Tom McHugh

photograph of hagfish slime by Andra Zommers

[fishsfailureson]

Hagfish that I did in my sketchbook while waiting for my tea (and finished at my desk). My main reference images were pacific hagfish. I accidentally skipped several pages while drawing my last sketchbook piece. Whoops.

Also if anyone has any suggestions for fish I should draw please put them in the notes of this post.

If you're going to like please reblog as well! Likes are appreciated but they don't give the same visibility that reblogs do.

[rbade-art]

[fishenjoyer1]

Fish of the Day

Today's fish of the day is the Pacific Hagfish!

The pacific hagfish, also known as the california hagfish, and scientific name  Eptatretus stoutii, is known for being the widest spread hagfish species, and one of the deepest living. Their range stretches from the Northern sections of Alaska all the way down to Baja, California, living at depths of 16-966 meters, or 50-3,200 feet. Along this range they prefer to live on fine silt and clay bottomed areas of the continental shelf, or upper shelves, their swimming skills are weak and so they spend much of their time along the sea bed. Although currently unproven, it is thought that during the fall these hagfish migrate to deeper waters, remaining until the winter, which is consistent with other hagfish migration patterns.

Hagfish first emerged in the fossil record as far back as 310 million years ago, with animals resembling the modern hagfish we know today 100 million years ago. To this day, hagfish still serve as a cause for confusion when it comes to defining fish as a taxonomic bracket. As a jawless fish that broke off just before the jaw was evolved, and sharing their infraphylum with lampreys, they break up a definition of fish that include the movement of the jaw as a definer. However, this lack of a jaw doesn't stop their hunting style from being just as interesting as us vertebrates who do contain a mouth that opens and closes.

Like all hagfish, the pacific hagfish establishes a hold onto prey before tying its body into knots and untying to generate a ripping force to tear off pieces of flesh. Due to this, a majority of their diet consists of already dead animals, forcing them into the scavenger role. Other than what the hagfish can scavenge, they also eat polychaete worms along the seabed, shrimp, other hagfishes eggs, and small cephalopods. Strangest of all, this animal can absorb amino acids through the skin. The other notable feature of hagfishes is their slime. When threatened, they can ooze a slime made of specialized mucus out of slime glands. This is known for expanding over 10,000 times its original size in less than a second. This slime can be used to slip away from predators who may have already gotten a hold on them, but also to clog the gills, choking out predators before they can get the chance to escape, and providing them with a meal.

The reproduction of hagfish is not well understood, but let's go over what we do know. Female hagfish will lay eggs within a muddy burrow it has formed or other structures it may find, and males will come to fertilize externally. After this, female hagfish will remain in the burrow to protect the eggs from any potential predators or other hagfish, until they hatch. Once they have emerged from their eggs, at a size of 6-8cm in length, they are already in the same shape they will remain the rest of their lives, as they lack a larval stage. Their life cycle lasts for up to 40 years in the wild, and they can get as large as 25 inches in length by sexual maturity, with a typical length of 17 inches.

That's the pacific hagfish, and have a wonderful Wednesday, everyone!

[myzaza]

™

[bethanythebogwitch]

Wet Beast Wednesday: hagfish

After taking last week off for mental exhaustion I have returned! And what better way to mark my return than with a shitload (or perhaps a highway load) of slime? Today I'm returning to the agnathan trenches to dredge up one of two living groups of jawless fish. I covered lampreys before, so now it's hagfish time. These ooey gooey critters are both fascinating and kinda gross. Now get ready, because it's time for slime.

(Image: a hagfish in profile. It is a long, brown, eel-like animal with a fin encircling the tail and a small head with no visible eyes or mouth. End ID)

Hagfish, also known as slime eels, are approximately 76 members of the class Myxini. In addition to the living species, hagfish have been preserved in the fossil record, letting us track their evolution through history. Hagfish are one of two living groups of agnathans, commonly known as jawless fish, with the other being the lampreys. As the name suggests, jawless fish are vertebrates without hinged jaws. Way back when bones were the cool new thing in town, agnathans represented the entirety of the vertebrates and were extremely diverse, but the evolution of jawed fish resulted in them getting largely outcompeted, leading to all lineages but the hagfish and lampreys going extinct. Genetic studies indicate that hagfish and lampreys are more closely related to each other than either group is to any other vertebrate. Because they are the only jawless fish left, hagfish and lampreys are of interest to scientists studying the evolution of vertebrates.

(Image: a hagfish coiled up, under orange light. The head is visible, featuring small sensory barbels and a large hole that resembles a mouth but is actually the nostril. End ID)

Hagfish are eel-shaped animals that range in length from a few centimeters to over a meter in the largest species, Eptatretus goliath. They have no scales, flattened tails that bear the only fin, and simple, eyeless heads. The heads bear sensory barbels, a single nostril, and the mouth. The mouth has two pairs of rasping plates that normally sit within the mouth, but can be everted to face outwards. The plates can grab food and pull it into the mouth to be swallowed. Hagfish do not have true eyes, but they do have eyespots that can sense light and dark. Interestingly, their fossil ancestors did appear to have fully-developed eyes that reduced in complexity until the present state. Likewise, ancestral hagfish had a true vertebral column made of cartilage, but modern hagfish only have remnants of their ancestor's vertebrae. Hagfish skin is very loosely connected to the internal body, only attached along the spine and slime glands. This makes the skin very flexible and harder for predators to grab. A third of the blood is contained between the skin and body and is pumped around with the heart as well as a few additional pumps that act as auxiliary hearts. Hagfish have some of the lowest blood pressure of any vertebrate and the highest blood volume to body mass ration of any chordate. Hagfish are also the only vertebrates that do not osmoregulate, meaning they cannot regulate the amount of salt in their bodies. Changes in salinity, especially moving to a lower salinity environment, are very dangerous to hagfish. Hagfish skeletons barely qualify, consisting of only a skull, notochord, and fin rays, all made of cartilage. The gills are internal. Water enters through the mouth and is forced over 5-16 internal gill pouches, then ejected through pores in the side of the body.

(Image: a closeup of a hagfish head with the rasping plates everted. The plates are mounted on pink tissue around the pharynx. there are two plates on either side of the pharyx which look like rows of small, sharp teeth. End ID)

That's all well and good, but you're here because of the slime. The hagfish's main defense is to create lots and lots of slippery slime. The slime helps them slip away from predators. If a fish tries to eat a hagfish, the slime can clog up its gills, forcing the fish to either release the hagfish or suffocate. A common factoid is that a single hagfish can turn a 5-gallon bucket of water into slime in seconds. To produce the slime, the hagfish releases threads made of special proteins into the water from glands on its skin. These proteins react with seawater to create a matrix of trapped water held together by filaments similar to keratin. The slime matrix can expand 10,000 times its original size in 0.4 seconds of exposure to seawater. The slime is quite durable and resistant to breaking and dissolving in water. After sliming, hagfish have been seen wrapping their bodies into an overhand knot and running themselves through the loop to scrape the slime off of themselves. Its possible that the slime also impairs the hagfish's ability to use it's gills and it needs to do the know to get the slime off and breathe again.

(Image: a person reaching into a holding tank full of hagfish and pulling out an armload of thick, viscous, white slime. End ID)

(Video: a hagfish in the wild demonstrating its knotting behavior. This one is going in the opposite direction usually seen: tail-to-head instead of head-to-tail. End ID)

Hagfish are found in most of the oceans, with range varying based on species. They are benthic animals that rarely swim far above the seafloor. Some species dig burrows to shelter in while others will shelter under rocks and other structures to avoid predators. While lying on the sediment, some hagfish species will coil up while others will lie straight. Hagfish are carnivorous and feed with a combination of hunting and scavenging. A large portion of the hagfish diet consists of polychaete worms and other known prey species include small crustaceans and echinoderms. Some species have been known to hunt burrowing fish, possibly by clogging up the burrows with slime to suffocate the prey. If you've seen a documentary about deep-sea fish you probably know about hagfish scavenging. Using their large nostril and sensitive sense of smell, hagfish can sense carcasses from long distances and are often some of the first scavengers to arrive at a new body. They use their rasping plates to pull bits of meat off of the carcass. A similar behavior to the slime-cleaning knots is seen when scavenging, but in reverse, going from tail to head instead of the other way around. This grants the hagfish additional mechanical advantage, allowing it to rip off larger chunks of food. Hagfish will burrow into larger corpses, possibly to get access to a food source with less competition than the outside of the body. Hagfish act as part of the deep ocean's cleaning crew, consuming corpses before they can decay and release potentially harmful chemicals into the water or act as sources of disease. Unlike any other living chordate, the food a hagfish swallows is encased in a permeable membrane during digestion. Hagfish can also absorbed dissolved nutrients through their skin. Hagfish have a very slow metabolism and ones in captivity have been observed going for up to 7 months between meals.

(Image: several hagfish feeing on the body of a fish. The hagfish have their heads on the fish's body and one hagfish is entering the fish's mouth. End ID)

Hagfish reproduction is still something of an enigma as so many of them live in the deep sea, making it difficult to observe them reproducing. It has been observed that females seem to outnumber males, with the exact ration varying depending on species. In some species, the sex ratio is almost even, while in others, there are 7 females to each male. however, it should be noted that females mature sexually faster than males and it has been suggested that this is responsible for the apparent skewed ratio. Hagfish eggs have tufts at the end that cause them to get stuck to each other like velcro. It has been suggested that eggs are laid in clusters possibly in burrows, beneath rocks, or protected with slime. Some species seem to have a mating season and seasonally migrate. Hagfish have only a single ovary or testicle (the latter of which has been described as unusually small by scientists and bullies in the deep-sea locker room) and they have no specialized reproductive tract. Instead, gametes are released into the main body cavity and must find their way to the anus to leave the body. Hagfish embryology is poorly understood, though it has been reported from studies of Eptatretus stoutii (Pacific hagfish) that the eggs can take up to 11 months to hatch. Hagfish have no larval stage, unlike lampreys and bony fish.

(Image: a group of 9 hagfish eggs in a plastic tub. The eggs are ovoid and dark yellow, with tufts of fibers at each end. End ID)

The conservation status and needs of most hagfish species is hard to discern because of the depths they inhabit. Threats to them include bycatch, as hagfish are often caught during deep-sea dredges. It is alos possible the chemical pollutants may be passed to hagfish through scavenging. There is a commercial fishery for hagfish, which is largest off of the west coast of the Americas. Hagfish are eaten as a delicacy in Korea and less commonly eaten in Japan. Most of the hagfish fishery goes to Korean food markets. Hagfish skin is also values as a durable leather and often marketed as "eel leather" or "yuppie skin". Study of the slime and the highly durable threads that produce it indicates they could be used to create very strong materials, similarly to spider silk. Research is currently being undertaken to find uses for hagfish slime and threads.

Once again, these cards show up in my posts (Image the Weird n' Wild Creatures card for hagfish, featuring an exaggerated drawing on a hagfish. End ID)

[eddieintheocean]

Big news for hagfish fans!!

references

Bardack, D. (1991). First Fossil Hagfish (Myxinoidea): A Record from the Pennsylvanian of Illinois. Science, 254(5032), 701–703. https://doi.org/10.1126/SCIENCE.254.5032.701

Fernholm, B., & Mincarone, M. M. (2023). A new species of the hagfish genus Eptatretus (Myxinidae) from the Bahamas, western North Atlantic. Journal of Fish Biology, 102(4), 962–967. https://doi.org/10.1111/JFB.15343

Fudge, D. S., Levy, N., Chiu, S., & Gosline, J. M. (2005). Composition, morphology and mechanics of hagfish slime. Journal of Experimental Biology, 208(24), 4613–4625. https://doi.org/10.1242/JEB.01963

Hirasawa, T., Oisi, Y., & Kuratani, S. (2016). Palaeospondylus as a primitive hagfish. https://doi.org/10.1186/s40851-016-0057-0

Miyashita, T., Coates, M. I., Farrar, R., Larson, P., Manning, P. L., Wogelius, R. A., Edwards, N. P., Anné, J., Bergmann, U., Richard Palmer, A., & Currie, P. J. (2019). Hagfish from the Cretaceous Tethys Sea and a reconciliation of the morphological-molecular conflict in early vertebrate phylogeny. Proceedings of the National Academy of Sciences of the United States of America, 116(6), 2146–2151. https://doi.org/10.1073/PNAS.1814794116/-/DCSUPPLEMENTAL

Parasramka, V. (2023). Manufacturing synthetic Hagfish slime skeins using embedded 3D printing. https://hdl.handle.net/2142/120467

Siu, R. (2023). Additive manufacturing methods for fabricating synthetic Hagfish skeins. https://hdl.handle.net/2142/120593

Zintzen, V., Roberts, C. D., Anderson, M. J., Stewart, A. L., Struthers, C. D., & Harvey, E. S. (2011). Hagfish predatory behaviour and slime defence mechanism. Scientific Reports 2011 1:1, 1(1), 1–6. https://doi.org/10.1038/srep00131

[artsfromspace]

White sturgeon Acipenser transmontanus

They have such goofy little eyes, I never realized :D

Aside from being cool ancient weirdos, they're one of the animals I actually most associate with going to the zoo - there's a sturgeon pond outside my local zoo and I always love seeing them!

So now they're in my little zoo too!

You can look them up or go by vibes :D If you suggest something else and it doesn’t win, I’ll add it to my list for the future!

[dailymarinefish]

day 132, 07/06/24 - fish of the day is the pacific hagfish (Eptatretus stoutii)

[covenawhite66]

This species has unique sets of microchromosomes. The genome alters itself when microchromosomes are lost when a creature ages and develops but the microchromosomes only remain in the reproductive organs.

This evolved in vertebrates being able to clone their genome in reproduction and to turn off certain genes in cells.

This creature is the origin of the complex brain, sensory organs the jaw, the limbs, and a greater number of switches that turn genes on/off.

This paper is on Hagfish phylogenomics and gene family evolution being the origin of WGD or a sister group of vertebrates to the first to have multiple sets of chromosomes.

Whole-genome duplication (WGD) evolved in vertebrates during the late Cambrian and early Ordovician periods.

We calculated the likelihood of gene duplication and loss patterns under the competing R1 and R2 hypotheses.

[newsnoshonline]

Pacific Hagfish: l'antica creatura delle profondità marine che può soffocare uno squalo vomitando melma Il Pacific Hagfish: un’antica creatura marina dalle abilità sorprendenti Nome: Hagfish del Pacifico (Eptatretus stoutii) Dove vive: Profondità marine di acqua fredda in tutto il mondo, solitamente al di sotto dei 90 metri di profondità Aspetto e Caratteristiche Questi pesci primitivi, senza pinne o scaglie, ricordano giganteschi lombrichi con denti spaventosi. Crescono fino a 64 centimetri di lunghezza e sono imparentati con le lamprede. Non possiedono mascelle ma hanno un teschio. Abilità Sorprendenti La caratteristica più straordinaria dei Pacific Hagfish è la capacità di produrre una melma che può abbattere persino uno squalo. Quando attaccati, sparano una melma appiccicosa sulle

[epigen-papers]

Bioinformatic and fine-scale chromosomal mapping reveal the nature and evolution of eliminated chromosomes in the Japanese hagfish, Eptatretus burgeri, through analysis of repetitive DNA families

Pubmed: http://dlvr.it/SvJjt5

[jumpintothewaves]

Weirdo Wednesday

Hello and welcome to Weirdo Wednesday! This week’s weirdo is...

The Pacific Hagfish: Eptatretus stoutii

Take a moment and imagine you are at the bottom of the ocean where it’s too dark for light to penetrate. You look up and see a dead whale sinking slowly, until it finally hits the bottom of the seafloor. Who is the first to ravage this bounty from above? The hagfish! At first glance it looks like a long, tubular eel without a jaw (or stomach). They have bad vision, but excellent senses of smell and touch. According to fossil records these primitive weirdos have remained unchanged in 330, million years! I guess if it ain’t broke... 

Slime and other bodily things

This primitive weirdo is a scavenger like many benthic deep sea dwellers. Normally, the hagfish is found burrowed in the mud, waiting for invertebrates to get too close, but whale falls are a fun treat! Hagfish are so excited to see dead whales that they bury themselves into the carcass, and tie themselves into knots (literally) as they try to scrape food off with their 2 rasps on their tongue. This weirdo’s most famous bodily function however it its ability to produce copious amounts of mucus as a defense mechanism. The mucus becomes a  sticky slime as it makes contact with the seawater and can suffocate predators!

Everyone has a roll

The hagfish may be simple, slimy, and unattractive, but it has an important role to play in our oceans ecosystem. This weirdo is a detritivore, meaning it eats dead things. This is not only important for cleaning up the decomposing organisms, but breaking down nutrients from the dead things and recycling them back into the ecosystem. The hagfish are part of natures clean up crew, a job that should not be taken lightly! And they do this for about 40 years... Did I mention they live that long?

Watch this video of the hagfish escaping predation by slime!!

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[max1461]

Iraq my brain (easy)

Iran away (easy)

Yeah, I Kuwait a minute (easy)

Oman, that was crazy (easy)

I know you don't believe me, but I swear it Isreal (easy)

Micheal Jordan (alt: Jordan curve theorem) (easy)

Yemen, I totally agree (easy but I did have to think a minute)

My friend asked me to pass him his large German beer mug, so I said ok and gave my Palestine (medium)

Wow, looks like we Qatar selves a big fish (medium)

Would you like me to Syria a steak? (medium)

Me: "I'll have the Unagi please." Waiter: "Ok, I'll bring UAE-l" (medium, also bad)

As a music producer working with many famous clients, I gave a ceLebenon-negotiable contract (hard)

My colleague Beatrice at the SCP foundation who I'm secretly having a romance with: "those data structures... they encode memetic hazards. Anyone who looks at them will instantly drop dead after 24 hours." Me, not sure what to say as the realization sets in that I looked over a few of those data structures yesterday just after lunch as part of some routine experiments, and... it's already 11am: "I.. yesterday I... I saw the array Bea. Uh..." (very hard)

The walls of the castle can only be breached by a hagfish with exactly seven gill apertures? Right sir, I'll get the siege eptatretus (impossible)

[awwsocuteanimals]

"Pacific hagfish (Eptatretus stoutii) in a hole" at the Cordell Bank National Marine Sanctuary in California, United States of America. This photograph was taken by Linda Snook in 2004. Credit: NOAA / CBNMS

[bizarrobrain]

Eptatretus stoutii (Hagfish) feeding on a dead whale