First-stage phyllosoma larvae of the rock lobster
Jasus edwardsii attached to and fed on larvae of the
Tasmanian trumpeter fish, Latris lineata, when the two
were placed together in an aerated, through-circulating, sea-water aquarium.
Scanning electron micrographs of the mouthparts showed adaptations suitable
for scraping and cutting soft substrata. Phyllosomas removed from the fish
while feeding had pigment particles from the fish integument throughout their
digestive tracts. The behaviour of these phyllosomas, swimming in a Petri
dish, was recorded with a microscope and video system. The presence of the
pigment particles made it possible to see the lumen of the gut diverticulae
and parts of them undergoing regular contractions. Transmission electron
micrographs of the gut showed that the parts of the gut that contracted in the
video records have well developed muscle bands associated with them. The
ultrastructure of the digestive tract is relatively uniform throughout and is
lined by cells resembling the undifferentiated (E) cells of other scyllarid
and palinurid larvae. Extensive folding of the wall, together with a brush
border on the digestive cells, results in a large surface area for absorption.
There is no grinding or filtering apparatus in the digestive tract. The
behaviour of the phyllosoma, structure of the mouthparts, and ultrastructure
of the digestive tract, suggest that the first-stage phyllosoma of
J. edwardsii is adapted for removing soft tissue from
gelatinous organisms and pumping it around the digestive tract.
Luminous vibriosis in rock lobster Jasus verreauxi (Decapoda: Palinuridae) phyllosoma larvae associated with infection by Vibrio harveyi