Starting a sentence with an adjective, is it possible?

[Egyption Arrow]

In the name of the Merciful Allah,
Hi,please read carefully the last phrase of this quoted paragraph: It should be obvious that cetaceans are mammals. They breathe through lungs, and not through gills, and give birth to live young. Their streamlined bodies, the absence of hind legs, and the presence of a fluke and blowhole cannot disguise their affinities with land-dwelling mammals. However, unlike the cases of sea otter and pinnipeds, it is not easy to envision what the first whales looked like. Extinct but already fully marine cetaceans are known from the fossil record. How was the gap between a walking mammal and a swimming whale bridged? Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.
I'm not sure I get this phrase fully. This is how I see it: fossils, that were clearly intermediate, or transitional, between land mammals and cetaceans, were missing until recently. My question is: if my understanding is right, how could the author start the phrase with an adjective, and why?

[Soup]

Hi Egyption Arrow

Fossils [that were] clearly intermediate, or transitional, between land mammals and cetaceans were missing until recently.

The author has topicalized the phrase 'missing until recently' giving:

Missing until recently were fossils ... .

From

Fossils ... were missing until recently.

The rule is this, when you topicalize, or bring a phrase to the front of a clause, the subject and verb invert:

Fossils were missing => missing were fossils

Above, the subject-verb set 'fossils were' becomes 'were fossils'.

[Egyption Arrow]

What can I say? I wish all replies were such like this one.