The embryonic cell lineage of the nematode Halicephalobus gingivalis (Nematoda: Cephalobina: Panagrolaimoidea)

This paper describes the nearly complete embryonic cell lineage of the terrestrial nematode, Halicephalobus gingivalis, up to somatic muscle contraction, resulting in the formation of 536 cells, of which 24 undergo programmed cell death. Halicephalobus gingivalis has a 94% lineage homology with both Caenorhabditis elegans and Pellioditis marina, and a fate homology of only 86% and 78%, respectively. Although H. gingivalis belongs to a different superfamily than C. elegans and P. marina, its cell lineage is remarkably consistent with them. Variations in the fate distribution of cells among the different species were only observed at the end of the cell lineage. The data presented here show that the polyclonal cell specification is much more widespread in clades 9 and 10 and is not a highly derived trait that is specifically linked to the fast development of the model organism C. elegans.