In Aliens: Colonial Marines (published by Dark Horse Comics), a group of marines wind up on a colony planet known as 'Bracken's World'. It is primarily oceanic, with large amounts of sea kelp.
Stranded on one of the kelp beds following an APC breakdown, they are attacked from underwater by large Xenomorphs whose top halves resemble that of a Queen's, and whose lower halves - below the waist - are more whale-like, with a lateral tail fin and several trailing tentacles. It can be inferred that this host-based species were a result of impregnated whales. Swimmers can swim up to seventy miles an hour, it is not known if these Xenomorphs can stay on land.