Zoanthropes are a species of Tyranid created solely to harness the potential psychic power of the Hivemind, in effect a type of psychic artillery used in Tyranid planetary invasions and a synapse creature used to carry the orders of the to transmit hive minds to lesser creatures.
Neurothropes are evolved versions of the normal Zoanthropes. These alpha beasts have the ability to drain their enemies' life force to power their attacks. There are some who believe that the Neurothrope tribe is the Destiny Descendant of Malan'tai, which is a truly terrifying concept for all sentient races.
Neurothropes can also use their parasitic power to heal nearby Zoanthropes, helping protect themselves from the psychic energy overload that normally overwhelms these creatures. A combined army of these psychic bioforms is indeed a formidable threat.
This kit can alternatively be built as three Venomthropes, three Zoanthropes or as two Zoantrophs and one Neurotroph.