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River and lake
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12-12-2016, 06:34 PM
( This post was last modified: 12-13-2016, 12:46 AM by sanjay
Edit Reason: corrected the format
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Outsized jaw muscles allow the black piranha to exert bite force equivalent to 30 times its bodyweight, a feat unmatched in the natural world, according to results of a finger-risking study.
Other animals like the great white shark, the hyena and the alligator can deliver more forceful bites, but their crunching power becomes much less impressive when viewed in relation to their overall size and weight, researchers said. In fact, relative to their size, piranhas outperform even prehistoric monsters like Tyrannosaurus rex and the whale-chomping megalodon, a massive shark that preceded the great white, said the study. Published in the journal Scientific Reports, the research saw scientists catch 15 black piranhas in Brazil's Amazon River basin and risk their digits by teasing a customised force gauge between their serrated jaws. The fish, ranging from about 20 to 37 centimetres (eight to 15 inches) in length, 'readily performed multiple defensive bites' on the gadget, wrote the team from the United States, Egypt and Brazil. This was the first live measurement of bite force taken from the black piranha (Serrasalmus rhombeus), the largest of the notoriously carnivorous species. Such undertakings are 'rare, dangerous and difficult to perform,' wrote the research team. 'While anecdotes of piranha-infested waters skeletonising hapless victims are generally hyperbole, the effectiveness of their bite is not,' the scientists added. They pointed to 'documented cases of S. rhombeus biting off and consuming human phalanges' - the bones found in fingers and toes. The measured bite force of the black piranha, at 320 newton (N), was nearly three times greater than that exerted by an American alligator of comparative size, said the study. One newton is the force required to move a kilogramme (2.2 pounds) of mass at one metre (3.25 feet) per second squared. It has jaw muscles of an 'extraordinary' size and a highly modified jaw-closing lever, said the team. In fact, the muscle complex makes more than two percent of the black piranha's total body mass. The team also used the data they gathered to estimate the bite force of the extinct Megapiranha paranensis to have been between 1,240 and 4,749 N. The fish from the Miocene period, which ended about five million years ago, would have been about 70 centimetres long and weighed about 10 kilogrammes (22 pounds), they said. Our analysis predicts Megapiranha's bite was equivalent to the anterior bite force of a great white shark weighing over 400 kilos (880 pounds)," said the report. And though their diet remains a secret of history, the monster fish would have been able to crush turtles, armoured catfish and even larger terrestrial animals. 'If our fossil reconstructions and simulations are correct, then Megapiranha paranensis was indeed a ferocious bone-crushing mega-predator of the Miocene epoch,' just like its modern-day relative, said the report. 'Our results for living and extinct species validate the fearsome predatory reputations of piranhas.' http://www.dailymail.co.uk/sciencetech/a...-find.html
Some of my favorite aquarium fish are Cichlids.
They are fresh water fish found in Africa (african cichlids) Central and South America. Depending on the location, cichlids have developed into many classifications. Over the years I have had many, at the moment I no longer keep any since my Green Istlantum died a year back. But I will post a few of my favorites with a brief description. Lets start with the Lion/Tiger/Polar Bear of the Cichlid world, The Dovii  *This image is copyright of its original author These guys can get up to 24'' or more and are found in C. America Depending on the location, Dovii like most Cichlids have slight variations in color, body shape and size. Dovii belong to a genus known as Parachromis, this genus includes Dovii Managuense Motoguense Loisellei Friedrichsthalii but no parachromis species gets as large or aggressive as the Dovii. The dovii is a strictly predatory cichlid and prefers to hunt by ambush. I am not joking when I say dovii are aggressive, any dovii owner will agree. They hit the glass "glass bang" harder than any other fish, they are intolerant of other fish and if you planned on having an adult pair in a community setting, you'd need a minimum of 600 gallons. But when it comes to beauty, they are 2nd to none. Next up is the S. American equivalent to the Dovii, it's called the Umbee The Umbee  *This image is copyright of its original author The Umbee is very similar in size to the Dovii, there is a ton of overlap between the largest specimens. But the umbee is an open water predator so it arguable needs even more space than a Dovii when keeping it in a aquarium setting. In terms of aggression, the umbee isn't quite as belligerent as the Dovii but it still will not tolerate tank mates when its an adult. Like the dovii, the umbee has many variations depending on location and it's beauty is also legendary. Next is arguably the most aggressive of them all, it's called the Beani Cichlid Beani  *This image is copyright of its original author Beani are notoriously hard to care for, they are very prone to Bloat. But if an experienced keeper can maintain their health until adulthood, they are blessed with one of the most aggressive and beautiful cichlids around. The beani is a large central american cichlid, not quite as large as the Dovii or Umbee, the Beani usually hits the 16'' I'll continue with some profiles as I get the time... 
Next up are the Parachromis Genus, these cichlids are found in C. America, they are torpedo shaped, they all have sharp teeth and most are omnivorous/carnivorous
The Dovii is the largest of the Family as I noted above.  *This image is copyright of its original author The next largest is the Managuense Cichlid aka Jaguar Cichlid  *This image is copyright of its original author These guys get up to 17'' or so, they are fairly aggressive, especially at a younger age, they seem to do better than most in a community setting if surrounded by other large aggressive fish. They are arguably the most beautiful Parachromis species, personally they are one of my favorite fishes to keep. The 3rd largest is called the Motoguense or Tiger Cichlid. The most impressive variation of Motoguense is the Red Tiger Motoguense  *This image is copyright of its original author RTM gets to around 13'' or so, they have fairly similar temperaments to the Managuense Next is the Fredrichsthali  *This image is copyright of its original author These guys grow to around 11'' and aren't quite as aggressive as the other 3 mentioned above. Last of the Group is the Loisellei Cichlid  *This image is copyright of its original author These are also small, their max size usually around 11'', their aggression is similar to the the Fred. (12-13-2016, 11:08 AM)parvez Wrote: Great info pckts. Thanks. But are cichlids more dangerous than piranha? Aggressive cichlids will be much more territorial than a piranha. The cichlids will chase your finger, attack you when you clean a tank, glass bang, fight any and all comers, so I'd say in a tank setting, yes cichlids are more dangerous. Piranha are definitely the more dangerous fish though. Their teeth are nasty, they take chunks out with one bite, they don't need to be tank aggressive I guess, they aren't going to attack the tank or go after you when cleaning it, if anything they'll be running scared. But there is one piranha in which those rules don't apply. I'll post a video on it when I get to work. (12-13-2016, 07:29 PM)Pckts Wrote:(12-13-2016, 11:08 AM)parvez Wrote: Great info pckts. Thanks. But are cichlids more dangerous than piranha? Thanks for the detailed explanation pckts. I got it completely.
As promised...
The Serrasalmus rhombeus Or better known as The Black Rhom These guys are a super aggressive and a territorial Piranha, they aren't like the standard Red Belly Piranha who are pack hunters, these guys prefer the solo life. They are tank aggressive, food aggressive and just all around aggressive. When comparing them to Cichlids, it's no contest. A cichlid is mouth fighter, they lip lock then hit and run while a Rhom doesn't mess around with lip locking since it's teeth are too nasty and any attempt to fight like that will result in a missing lip. Here you can see a young Dovii learning this the hard way below
@Pckts, they also seem to be having pharyngeal teeth, an alien like feature in them.
https://www.scientificamerican.com/artic...hlid-fish/ (12-15-2016, 04:41 PM)parvez Wrote: @Pckts, they also seem to be having pharyngeal teeth, an alien like feature in them. You want to see a cool set of "throat jaws"  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author The extra set of jaws allow them to hold fast as the eel works it's way up the prey item. Pretty much if a moray gets a hold, that's all she wrote. Edit: Not a river or lake predator but figured it fit with the discussion.
An article on their adaptations and evolution,
Africa's Lake Victoria is home to one of evolution's greatest experiments. In its waters, what began as a single lineage belonging to the cichlid family of fishes has since given rise to a dazzling array of forms. Like Charles Darwin's famous finches, which evolved a wide range of beak shapes and sizes to exploit the different foods available in the Galápagos Islands, these cichlids represent a textbook example of what biologists term an adaptive radiation—the phenomenon whereby one lineage spawns numerous species that evolve specializations to an array of ecological roles. But the Lake Victoria cichlids far surpass Darwin's finches in the astonishing speed with which they diversified: the more than 500 species that live there and only there today all evolved within the past 15,000 to 10,000 years—an eyeblink in geologic terms—compared with the 14 finch species that evolved over several million years. https://www.scientificamerican.com/artic...id-fishes/ |
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