Novelization
Written by Yvonne Navarro from the original screenplay, the book gives several in depth details about the characters not seen in the film, such as Sil's ability to visualize odors and determine harmful substances from edible items by the color. Gas appears black, food appears pink, an unhealthy potential mate appears to give off green fumes. Other character details include Press's background in tracking down AWOL soldiers as well as the process of decoding the alien signal. Although no clues are given as to its origin, it is mentioned that the message was somehow routed through several black holes to mask its point of origin.
Parts of these extra scenes and details are shown in the comic book adaptation by Titan Books. There is also a novelization by Navarro for Species II which follows the film's original screenplay with added scenes.
Read more about this topic: Species (film)