The taxonomy of the Chelodina genus

  Key to subgenera and species

  1  Plastron broad, covering or almost covering the anterior orifice of the shell in ventral view; intergular scute approximately twice as long as the suture between the pectoral scutes; length of head and neck equal or slightly less than
       length of the carapace; dorsum of neck with many blunt conical tubercles; fluid with a pungent odour secreted from ducts in the inguinal and axillary pockets when distressed ............ subgenus - Chelodina...... 2
  –  Plastron narrow, covering only about half of the anterior orifice of the shell in ventral view; intergular scute approximately the same length as or shorter than the suture between the pectoral scutes;
      head and neck longer than carapace; dorsum of neck lacking obvious tubercles; fluid from ducts in the inguinal and axillary pockets if with noticeable odour, not pungent ............................................................... 8

  2  Expanded anterior lobe of the plastron moderate, not completely covering the anterior orifice of the shell in ventral view; sutures of plastron not edged with black, or at most narrowly edged with black; posterior marginal
      scutes not elevated medially to accommodate the tail ............................................................................................................................................................................................................................................ 3
  –  Expanded anterior lobe of the plastron very broad, covering the anterior orifice in ventral view (and all soft parts when withdrawn); sutures of the cream or yellow plastron broadly edged with black; posterior marginal
      scutes elevated medially to accommodate the tail ................................................................................................................................................................................................................... Chelodina longicollis

  3  Carapace strongly convex, distinctly oval in outline ............................................................................................................................................................................................................................................... 4
  –  Carapace very flat, almost circular in outline ........................................................................................................................................................................................................................ Chelodina steindachneri

  4  First and second marginal scutes approximately equal in size ................................................................................................................................................................................................................................. 5
  –  Second marginal scute distinctly larger than the first .................................................................................................................................................................................................................... Chelodina mccordi

  5  Jaws and associated triturating surfaces robust ...................................................................................................................................................................................................................................................... 6
  –  Jaws and associated triturating surfaces petite (as in C. longicollis)....................................................................................................................................................................................... Chelodina pritchardi

  6  Head moderate, without distinct convexity to the dorsum of the head......................................................................................................................................................................................................... 7
  –  Head robust, disproportionately large, with distinct convexity of the dorsum of the head ........................................................................................................................................................... Chelodina reimanni

  7  Northern Australia .............................................................................................................................................................................................................................................................. Chelodina canni
  –  New Guinea .................................................................................................................................................................................................................................................................. Chelodina novaeguineae

  8  Carapace approximately oval; plastron of moderate length, less than twice as long as its width measured anterior to the bridge .............................................................................. subgenus Macrochelodina..... 9
  –  Carapace very narrow, plastron long, narrow, more than twice as long as its width measured anterior to the bridge... ...................................................................... subgenus Macrodiremys..... Chelodina colliei

  9  Ventral surface of the cervical scute longer than wide, or length and width approximately equal ......................................................................................................................................................... 10
  –  Ventral surface of the cervical scute much shorter than it is wide.................................................................................................................................................................................................. 11

  10 Distinct white patch immediately above and behind the tympanum, with or without dark blotches; ventral surface of the cervical scute longer than wide....................................................................... Chelodina parkeri
  –  No distinctive white patches on the head; length and width of ventral surface of the cervical scute approximately equal ...................................................................................................................... Chelodina expansa

  11 Width of head moderate, not dramatically wider than the neck; two barbels on the chin, if present ............................................................................................................................................. Chelodina oblonga
  –  Head very broad, dramatically wider than the neck, multiple prominent barbels forming a linear series on each mandible ....................................................................................................... Chelodina burrungandjii

Relationships within the Chelodina

Phylogeny of the Chelodina adapted from Georges and Thomson (2004) in press.

© Jan Matiaska and Scott Thomson, 2003