Fossil discoveries from the Devonian rocks of Scotland and Australia first revealed that the earliest jawed fishes, the placoderms, reproduced using copulation in much the same way as sharks and rays do today.
They also had the first paired pelvic skeletons, the precursor to the hind paired fins – and legs – of all animals. Their paired reproductive organs, called "claspers", probably developed in the same way as limbs.
The appearance of jaws and teeth in the first vertebrates was thus intimately linked to the origin of paired hind limbs (pelvic girdles) and an advanced kind of sexual reproduction.
The researchers found evidence that anatomical developments that enable copulation appeared earlier, in jawless fishes.
(Score: 0) by Anonymous Coward on Friday July 20 2018, @10:10PM (1 child)
"Even though I have "claspers", I self-identify as a girlfish".
- Millennial Fish, 1 million BC
(Score: 0) by Anonymous Coward on Friday July 20 2018, @10:13PM
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