title: Haustrum haustorium
text: # Haustrum haustorium
  
  Haustrum haustorium, common name: the brown or dark rock shell, is a large species of predatory sea snail, a marine gastropod mollusc in the family Muricidae, the murex snails or rock snails.
  
  ## Taxonomy
  
  Haustrum haustorium used to be the only species in the genus Haustrum. However, Beu (2004) reclassified a number of New Zealand's whelks, considering species in the genus Lepsiella to be synonymous with the genus Haustrum.
  
  ## Distribution
  
  This species occurs in New Zealand.
  
  ## Shell description
  
  A reliable characteristic for distinguishing Haustum haustorium from its congeners is the angle by which the aperture lip inserts on the shell: In Haustrum haustorium the angle is near-perpendicular, whereas in other species the angle is more acute (~45 degrees). Tan (2003) provides the most recent review.
  
  ## Ecology
  
  ### Habitat
  
  This rock snail's typical habitat is the mid and lower eulittoral zone of New Zealand's semi-exposed rocky intertidal shores. It is less common on algal-dominated sheltered shores.
  
  