(Reading) Pinnipeds, sea lions and walruses

Biologists have long maintained that two groups of
pinnipeds, sea lions and walruses, are descended from
a terrestrial bearlike animal, whereas the remaining
group, seals, shares an ancestor with weasels. But the
recent discovery of detailed similarities in the skeletal
structure of the flippers in all three groups undermines
the attempt to explain away superficial resemblance as
due to convergent evolution—the independent develop-
ment of similarities between unrelated groups in
response to similar environmental pressures. Flippers
may indeed be a necessary response to aquatic life,
turtles, whales, and dugongs also have them. But the
common detailed design found among the pinnipeds
probably indicates a common ancestor. Moreover,
walruses and seals drive themselves through the water
with thrusts of their hind flippers, but sea lions use
their front flippers. If anatomical similarity in the
flippers resulted from similar environmental pressures,
as posited by the convergent-evolution theory, one
would expect walruses and seals, but not seals and sea
lions, to have similar flippers.

Select the sentence in the passage in which the author
shows that the implication of the common view is
contradicted by a new finding.

The correct answer is " But the recent discovery of detailed similarities in the skeletal
structure…", but I think “But the conmmon detailed design found among…” can also be the answer. Please help me with this, thanks!

It could be, if the point hadn’t already been made! It is the first of the two where the author implies a new view. The second just supports that earlier implication.

I see. It seems I had better search from the begining.