Study: Fish Have Been Jumping on Land for 150 Million Years and Hiding it From the Fossil Record

By Douglas Main | October 11, 2011 2:01 pm

Jumping fish!Mosquitofish can leap with “skill and purpose.”

How did animals move from water to land? The answer may have just got a little murkier. A study published this month in the Journal of Experimental Zoology found that two distantly related fish share a similar method for jumping about on land, suggesting that a common ancestor evolved this ability long ago. But unlike amphibious fish such as the mudskipper, which has pectoral fins adapted to “walking” on land, these fish have no specialized equipment for leaping, and would therefore leave no evidence of their talent behind in the fossil record.

In the lab scientists placed fish on a moist surface and filmed their leaps using a high-speed camera (see video below). In this study researchers compared the western mosquitofish, which is known to hop onto land when pursued by predators, and the zebrafish, which doesn’t leave the water in its natural habitat. And yet in the lab both fish can jump with “skill and purpose,” and in very similar way. This led researchers to hypothesize that a common ancestor of the two fish evolved the capacity to jump on land, more than 150 million years ago. The researchers are currently filming the jumping behavior of every fish species they can get their hands on to conclusively determine whether jumping did in fact evolve once or whether it cropped up multiple times in different lineages.

Here’s a video of the western mosquitofish, or Gambusia affinis. Its trajectory, at about 45 degrees from the ground, makes it a “better” jumper than the zebrafish, giving it more distance per unit of effort. This makes sense, given that zebrafish don’t naturally leave the water:

Now for the zebrafish (Danio rerio). Notice how it bring its head toward its tail before leaping, the opposite of the the mudskipper’s technique:

Here’s the proficient jumper Kryptolebias marmoratus, a killifish that spends some of its time out of water while evading predators:

Finally, here’s a convict cichlid (Amatitlania nigrofasciata). Researchers analyzed this fish since it’s not known to display a jumping behavior outside of water. Scientists hypothesize this fish has lost the ability to leap on land, although it’s also possible that it never possessed that ability. Further study of related fish will help them find out.

Reference: Alice C. Gibb, Miriam A. Ashley-Ross, Cinnamon M. Pace, John H. Long. Fish out of water: terrestrial jumping by fully aquatic fishes. Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, 2011; DOI: 10.1002/jez.711

Image and video credit: Northern Arizona University.

CATEGORIZED UNDER: Environment, Living World
  • John Kwok

    I don’t think you can assert that this “finding complicates the study into the evolutionary transition of animals from water to land” when Teleosts (including these three taxa) – the most derived members of the Actinopterygii (ray-finned fishes) – are distantly related to the Sarcopterygii (lobe-finned fishes), which include the coelacanth and lungfishes as the only living descendants (not counting of course, land vertebrates, Tetrapoda, of which Tiktaalik is an early, transitional taxon); both lineages comprise the clade Osteichthyes (bony fishes). From a paleobiological perspective what is interesting is that at least some of the early Teleosts may have had an ability to leap onto land and survive briefly for short durations; again as I have noted, this does not refute the well-accepted theory that lobe-finned fishes are ancestral to the Tetrapoda that has been confirmed with the relatively recent discoveries of Tiktaalik, Acanthostega, and other related taxa.

  • Douglas Main

    John–Thanks for the comment. After going back and forth about changing the wording I decided to leave it as is. If early Teleosts could indeed jump around on land without leaving fossil evidence of the feat, it is a complicating factor to consider when drawing up relationships between these ancient fish (which is guided in part by fossil analysis).

  • John Kwok

    @ Douglas –

    No, I believe you should alter that comment lest someone thinks we don’t know the fish to tetrapod ancestor – descendant sequence which vertebrate paleobiologists Neil Shubin and Jennifer Clack, among others, have worked out in considerable detail in the past decade and a half (Shubin and his team discovered Tiktaalik; Clack’s team, Acanthostega.).

    I’m not a student of paleoichthyology (I have a background in invertebrate paleobiology.), but unless I am mistaken, teleost fish arose in freshwater environments sometime during the middle Mesozoic Era (would be approximately the Jurassic Period if the 150 million year date is correct), so fish jumping could have been a less derived (“primitive”) trait that early teleosts used to avoid predation or to escape from pools of evaporating water, like some that are dry and wet depending on the seasons in question. As for it being a “complicating factor”, I would strongly doubt that, given our now extensive knowledge of teleost fish evolution from both paleobiological and genomic data.

  • Matt

    While I appreciate the explanations above, I don’t see how this study could possibly complicate our understanding of the evolutionary history of fish. I am certainly no expert, but it appears that all this study shows is that the mechanism that diverse fish use to leap (flop) when on land is similar, despite taxonomic or geographic location. If I am reading this article correctly, the assertion is that this widespread behavior indicates that it is ancestral to all these species of fish–or rather that it developed before these various lineages diverged from one another. It seems to me that a much easier explanation would be that this behavior is simply an extension of sinusoidal movement, and is thus necessarily common among all fish. After all, what else could fish on land possibly do?

  • John Kwok

    @ Douglas –

    The study you’ve reported on merely documents, based on experimenta laboratory data, one probable evolutionary outcome in which one clade of Osteichthyes (bony fish) “invaded” a terrestrial environment sometime back in the middle Mesozoic Era (Jurassic Period, approximately 150 million years ago). The other example, well documented by the sequence that includes Tiktaalik, Acanthostega and Ichthyostega (long regarded as the “missing link” between lobe-finned bony fishes and tetrapods until recent discoveries by Clack, Shubin and others), dates from the middle to late Devonian Period of the Paleozoic Era (approximately 370 to 345 million years ago). For these reasons as well as those I mentioned yesterday, you can not conclude that “The finding complicates the study into the evolutionary transition of animals from water to land: the process didn’t necessarily include only transitional forms like the famous ‘fishapod’ Tiktaalik.”

  • John Kwok

    @ Matt –

    You’re absolutely right that this study doesn’t “complicate our understanding of the evolutionary history of fish”, though to be more precise, we are referring only to bony fish (Osteichthyes), not to other “fishes” like sharks, rays and their relatives or hagfish and lampreys. But, with regards to the more derived Teleost clade of Osteichthyes, this study, based on experimental laboratory data, may support the hypothesis that this behavior could be indicative of a less derived trait that was common to the earliest Teleosts, not that it is “simply an extension of sinusoidal movement…. common among all fish.”

    As for Douglas’ assertion that teleost fish have been “hiding it from the fossil record”, then that is quite a grand leap of faith. Why? Terrestrial environments are by their very nature, very poor environments for fossilization due to taphonomic aspects of the process of fossilization that have been demonstrated by such notable researchers of vertebrate taphonomy like physical anthropologist Pat Shipman and vertebrate paleobiologist Kay Behrensmeyer. In plain English, terrestrial environments are poorer than marine ones since they do not have locations that are easily subjected to rapid burial that would minimize decay of skeletal remains (via scavenging, microbial activity that would decompose such remains) and promote their potential preservation as fossils. Since terrestrial fossils are substantially rarer than those preserved in marine sedimentary strata, then one can’t say that terrestrial organisms, including some Teleosts, have been “hiding it from the fossil record”.

  • Douglas Main

    John & Matt:

    Thanks for your good points, and you’re right. I mischaracterized the impact of the study, so I’ve stricken the following sentence: “The finding complicates the study into the evolutionary transition of animals from water to land: the process didn’t necessarily include only transitional forms like the famous ‘fishapod’ Tiktaalik.”

    John, re: “hiding it” — The point is only that this jumping ability, as noted, requires no noticeable anatomical peculiarity and thus hasn’t been left, or “recorded,” in the fossil record (as opposed to, for example, the mudskipper’s modified fins, which can be fossilized). Obviously the fish weren’t “trying to hide” this ability, or anything like that. It’s just a playful way of getting the point across in a headline.

  • John Kwok

    @ Douglas –

    Thanks for your response to mine and Matt’s commentary. As for “hiding it”, it would be analogous to claiming that large sauropod dinosaurs had whip-like tails to lash out against hungry theropod dinosaurs. There is simply no proof from the fossil record that these dinosaurs had such an ability; with regards to teleost fish, I think yours could be best described as somewhat superfluous poetic license that might detract from your reporting of this very finding.

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