Like nearly all known pterosaurs, they presumably prey on fish (they do not eat their human victims).
Malcolm Wallace said that they were a new species, and they would seem to be a new genus as well given that he coined the name "Malcolmus". Given their long tails with skin flaps on the end, they appear to be members of the suborder Rhamphorhynchoidea rather than the suborder Pterodactyloidea, although unlike most (all?) Rhamphorynchoids they appear to have toothless beaks. Most or all Rhamphorynchoids lived in the late Triassic or Jurassic periods, so it might be seen as scientifically implausible to have a pterosaur with a Rhamphorynchoid-like tail living 85 million years ago. Some scientists do classify the family Anurognathidae as being a member of Rhamphorhynchoidea, and a single genus from this family, Dendrorhynchoides, is known to have lived in the Early Cretaceous period, though still significantly earlier than 85 million years ago when Terra Nova is set. And its appearance didn't look much like most Rhamphorynchoids, for example it had a much shorter tail than most of them as illustrated here, as well as a more rounded snout as seen in this drawing of its skeleton, which features a tail that was artificially lengthened by fossil dealers. The relationship of Anurognathidae to other pterosaur groups is uncertain, three possible trees are shown here. In addition, there was a group of pterosaurs called the Wukongopteridae which combined some rhamphorhynchoid features with some pterodactyloid features, and although the rock formations they have been found in are dated to the Late Jurassic by most studies, a few studies have dated them to the Early Cretaceous. Some Wukongopterids like Kunpengopterus did have long tails and small teeth, so one could imagine that the Cretaceous date is actually correct, and that Malcolmus could be related to them.