Phylogeny and biogeography of selected Harpacticoida

Ancorabolinae Sars, 1909 and Laophontodinae Lang, 1944

Up to date, both taxa were assigned to the family Ancorabolidae Sars, 1909. Nonetheless, recent studies point towards a paraphyletic state of “Ancorabolidae”.

Both groups are relatively small and, compared with other harpacticoid taxa, a relatively clear harpacticoid taxa. Their representatives are characterized by a more or less bizarre body shape, possessing often large cuticular processes and laterally extended swimming legs (Fig. on the right: Dorsiceratus ursulae George, 2006, Ancorabolinae, Ceratonotus-group, dorsal view).

Ancorabolinae as well as Laophontodinae are distributed worldwide in the oceans, but considered as being rather rare. Ancorabolinae inhabit predominantly muddy deep-sea substrates, whereas Laophontodinae may also be collected from shallow sandy areas and even algae.

The phylogeny of both taxa became of increasing interest in the past decades, and thanks to several recent findings, primarily in the Atlantic deep sea and on/around seamounts, indications to origin and distribution become of increasing clarity.

Argestidae Por, 1986

Argestidae Por, 1986 are considered as being typical deep-sea inhabitants. Systematics within the family is not yet resolved. Some genera (Argestes Sars, 1910, Bodinia George, 2004, Fultonia T. Scott, 1902, Mesocletodes Sars, 1910 sowie Neoargestes Drzycimski, 1967) could, in the meantime, be confirmed as monophyla. Moreover, the rather primitive genera Argestes and Fultonia could be assigned to the suprageneric monophylum Argestinae Por, 1986, based on several common derived characteristics (synapomorphies). Fig. on the right: Argestes angolaensis George, 2008, Argestinae, lateral and dorsal view.

Argestidae are collected from almost all deep-sea localities and thus may be quite useful for systematic, biogeographic, and faunistic comparison. Argestid material available from the Magellan Region, the low and high Antarctic, and the whole Atlantic deep sea serves for investigation within all above mentioned directions.

Cletodidae Por, 1986

Also Cletodidae Por, 1986 are still awaiting their clear phylogenetic characterization and assignment within the system of Harpacticoida. A phylogenetic neighbourhood of at least single genera (e.g., Cletodes Brady, 1872) to above mentioned Laophontodinae seems to be indicated by several characteristics, but is still awaiting its justification. In the context of a phylogenetic revision of Ancorabolinae and Laophontodinae, the same is needed to realize with Cletodidae.