Although some information is available on how calanoid copepods collect and handle food, there is very little information on the labrum and paragnaths, structures that are the last to receive food before trituration and ingestion. Five species were used to examine the nature of and differences between the labrum-paragnath complex, species with a variety of feeding modes ranging from detritivore to carnivore. The nature of the complex ranged from very simple in Eucalanus bungii bungii Johnson, 1938, to the heavily sclerotized labrum and paragnaths of the carnivore Paraeuchaeta elongata (Esterly, 1913) with its specialized anterior labral lobe. The labrum, which provides a semi-enclosed space for trituration by the mandible gnathobases, is hood shape while the columnar-shaped paragnaths, which hold and help move food towards the mandible gnathobases, contain setule and spicule armature elements. Not only the shape of the complex, but also its orientation are suggested to play roles in dictating dietary choices. The range of structures, from the simple complex of Eucalanus bungii bungii to the beak like complex of Heterorhabdus tanneri (Claus, 1863), along with its claw-like gnathobase armature, provide an indication of the morphological diversity found in the labrum-paragnath complex of calanoid copepods.
Homeotic gene and the arthropod head: expression patterns of the labial proboscipedia and deformed genes in crustaceans and insects.
Proc. Natl. Acad. Sci. USA96:
DaggM. J.FrostB. W.NewtonJ.1998.
Diel vertical migration and feeding in adult female Calanus pacificus, Metridia lucens and Pseudocalanus newmani during a spring bloom in Dabob Bay, a fjord in Washington USA.
Journ. Mar. Systems15:
Characterizing dietary variability and trophic positions of coastal calanoid copepods: insight from stable isotopes and fatty acids.
Specialized feeding mechanism in the pelagic copepod genus Heterorhabdus (Calanoida: Heterorhabdidae), with special reference to the mandibular tooth and labral glands.
Feeding ecology of copepodid stages of Eucalanus bungii in the Chukchi and northern Bering seas in October 1988.
Proc. NIPR Symp. Polar Biol.6:
WaloszekD.2003. Cambrian Orsten-type preserved arthropods and the phylogeny of crustacea. In: A. Legakis S. Sfenthourakis R. Polymeni & M. Thessalou-Legaki (eds.) The New Panorama of Animal Evolution. Proc. 18th Int. Congr. Zoology: 66-84.
Cell lineage analysis of the mandibular segment of the amphipod Orchestia cavimana reveals that the crustacean paragnaths are sternal outgrowths and not limbs.
Frontiers in Zoology3:
Vertical distribution, life cycle and body allometry of two oceanic calanoid copepods (Pleuromamma scutullata and Heterorhabdus tanneri) in the Oyashio region, western North Pacific Ocean.
J. Plankton Res.22: