Dan Abnett 
Extinction Event [EPUB ebook] 

Strange anomalies are ripping holes in the fabric of time, allowing creatures from distant past and far future to roam the modern world. Evolutionary zoologist Nick Cutter and his team must track down and capture these dangerous creatures and try to put them back where they belong. An Entelodon goes on the rampage down Oxford Street in central London causing untold damage and loss of life, and Cutter decides a new approach to tackling the anomalies is needed. When a mysterious Russian scientist arrives at the ARC, the Primeval team think they might have found the answer…