• Newly found scaleless cave fish is still evolving to cave life

    From Pro Plyd@21:1/5 to All on Mon Mar 10 16:10:02 2025
    https://www.iflscience.com/never-before-seen-golden-cave-fish-discovered-in-china-still-evolving-to-live-underground-78354

    Scientists have struck gold while searching
    for fish in a Chinese cave, having discovered
    a brand-new species that’s not only got a
    gilded exterior, but also appears to still be
    evolving.

    The fish, which was identified during surveys
    carried out in southwestern Guizhou Province,
    has been named the Xingren golden-lined fish
    (Sinocyclocheilus xingrenensis), after the
    nearby city. It’s thought to live exclusively
    in this area, although the researchers wrote
    in the study describing the new species that
    much else about its ecology is still to be
    discovered.

    They were able to separate the new golden
    fish from other members of its genus – many
    of which also live in caves carved out within
    southwestern China’s karst landscapes – based
    on its DNA and appearance. For example,
    compared to its most similar species within
    the Sinocyclocheilus genus, the Xingren fish
    is smaller and has a different number of rays
    making up its fins.

    But those are far from the only distinguishing
    features of this fish. In fact, looking beyond
    its golden gleam, there’s actually something
    quite confusing about S. xingrenensis.

    This fish is scaleless, which is a common
    adaptation for fish that live in caves. On the
    flipside, the Xingren golden-lined fish also
    has massive eyes, at least if you consider that
    it doesn’t seem to have much need for them
    given that it’s, y’know, pretty dark
    underground. Lots of other cave-dwelling
    creatures have either reduced eyes or have
    ditched them entirely. So, what’s going on?

    The answer, according to the study authors,
    could be that S. xingrenensis only moved into
    its cave habitat relatively recently, and as
    a result, it’s still in the process of
    adapting to its new home.

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