Learn English – How should I shorten this sentence

To rephrase without losing any of the meaning and disregarding the pragmatics of the questioner’s sentiment, I might say:

Of all the times that hearing news of a pregnancy has made me happy, yours ranks second.

But I think this formulation casts more light on the awkwardness of the sentiment than the questioner would have wanted.

I agree with the other answerers that although your intentions are kind, this is going to be an uncomfortable thing to hear, no matter how unawkwardly you phrase it.

Missing until recently were fossils [clearly] [intermediate,] [or transitional,] [between land mammals and cetaceans].

In your sentence, the adjective intermediate modifies fossils. This adjective is again modified by the adverb clearly. The adjective transitional is in apposition to intermediate and so also modifies it, or it could be said to be parallel to it: in that case, both adjectives modify fossils directly and should be in bold. Thirdly, intermediate is modified by the prepositional phrase between land mammals and cetaceans.

The following is my paraphrase of the sentence. Until recently, certain fossils were missing. What kind of fossils? Fossils that are clearly intermediate, or transitional, between land mammals and cetaceans.

There are various reasons why adjectives may sometimes come after the noun they modify; see this question for some thoughts about the subject: the superlative + noun + possible.