Systematics or Phylogenetics

Nudibranchs differ from most other molluscs in having secondarily lost their protective shell. The systematics, therefore, is based largely on the study of the soft parts.

All nudibranchs either have a branched or unbranched digestive mass. Cladohepatic nudibrachs have a branched digestive mass, while holohepatic nudibranchs have an unbranched digestive mass. On this basis of this and some other external morphological traits, it is useful to divide the Nudibranchia order into two clusters (Rudman & Willan 1998).

1.   Dendronotina, Arminina, and Aeolidina: all cladohepatic species

2.   Doridina: all holohepatic species

J. funebris belongs to the Doridina suborder, and therefore resides in cluster 2. Other characteristic traits of Doridina species include (Cimino et al. 1999):

1.   A pair of antero-dorsal chemosensory organs, named rhinophores

2.   Poster-lateral respiratory organ, the gills, usually arranged in a circle around the anus

3.   Lack cerata, and spicules arranged in ovoidal patterns on mantle.

It is always interesting to ponder the selective pressures required for a species to evolve hermaphroditism. It is likely that the following characteristics led to the evolution of simultaneous hermaphroditism in J. funebris:

·      single species populations are generally small

·      discontinuous distribution

·      populations comprised of individuals with low motility

Nudibranchia comprise four suborders; Dendronotacea, Doridacea, Arminacea, and Aeolidacea.

Doridoidea: gills encircle anus of posterior dorsum. 26 families, including Kentrodorididae (contains J. funebris), Chromodoris, Dendrodoris, Doris, GLossodoris, Onchidoris,