Cross-species matings


Upper: Hypselodoris bullocki and H. apolegma mating. Photo: Phil Slosberg.
Lower: Halgerda carlsoni and H. diaphana mating. Photo: Mitsuo & Ayumi Murakami.

One definition of a species is that it is a group of animals which mate with each other and produce viable off-spring. One consequence of that is that many species have evolved elaborate behavioural and anatomical barriers so that species mate only with their own kind. When two apparently different species are observed mating it is an event of some interest. It means either that our definition of the species involved is faulty, or that the methods these species use to identify their own kind is faulty. A number of such observations have been made by Forum contributors and links to their messages are listed below. See also some general messages below.

Chelidonura amoena & C. electra - Possible hybrid
Chromodoris annae & C. cf. colemani mating?
Hypselodoris bullocki and H. apolegma mating.
Hypselodoris sp and H. apolegma mating.
Risbecia tryoni & R. pulchella trailing. message 1, message 2.
Halgerda carlsoni and H. diaphana mating. [see second message.]
Phyllidia ocellata - colour forms? mating
Phyllidia ocellata & P. babai mating.

Authorship details
Rudman, W.B., 2003 (April 7) Cross-species matings. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

  1. Re: Cross-species breeding
    From: Cynthia Trowbridge, April 26, 2006
  2. Cross-species breeding - Sea Hares
    From: Jasmine Peters, March 8, 2006
  3. Cross-species matings
    From: Bill Rudman, April 9, 2003
  4. Cross-species mating
    From: Samuel K. Moore, March 8, 2003
  5. Re: Mating behaviour
    From: Hans Tibboel, March 3, 2003
  6. Mating behaviour
    From: Hans Tibboel, February 25, 2003
  7. Re: H. bullocki 'colour forms' mating
    From: Erwin Koehler, August 6, 2002

Show factsheet and all related messages