Ninoziphius platyrostris was an early beaked whale that lived during the late Miocene (~6 million years ago) in warm coastal waters covering what is now southwestern Peru. Its ancestors appear to have branched off from all other beaked whales very early in the group’s history, indicating a “ghost lineage” going back to at least 17 million years ago.
About 4.4m long (~14’5″), it was less specialized for suction feeding and deep diving than modern beaked whales. Also unlike most modern species its jaws were lined with numerous interlocking teeth, with heavy wear suggesting it may have hunted close to the seafloor, where disturbed sand and grit would have regularly ended up in its mouth along with its prey and steadily ground down its teeth during its lifetime.
Males had a pair of stout tusks at the tip of their upward-curving lower jaw, with possibly a second smaller set of tusks behind them, which were probably used for fighting each other like in modern beaked whales.
Its shallow water habitat and more abrasive diet suggest Ninoziphius’ lifestyle was much more like modern dolphins than modern beaked whales, and other early beaked whales like Messapicetus similarly seem to have occupied dolphin-like ecological niches.
These dolphin-like forms disappeared around the same time that true dolphins began to diversify, possibly struggling to compete for the same food sources, while other beaked whales that had begun to specialize for deep sea diving survived and thrived. Interestingly this ecological shift seems to have happened twice, in two separate beaked whale lineages – although only one of them still survives today – with bizarre bony “internal antlers” even independently evolving in both groups.
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