Hooge MD 2001 (citation) - "Childia groenlandica posesses not only a unique pattern of musculature (Figs. 6,7) but the layering of these muscles is also unique among acoels in that the relative positions of the subepidermal body-wall muscle fibers are reversed, with longitudinal muscle fibers lying outside of inner circular fibers, a condition first recognized by Luther (1912) (citation). These features, along with its unusual paired male copulatory apparatus, suggests that the Childiidae as it is presently known is polyphyletic. Additional endorsement for polyphyly comes from preliminary ultrastructural and immunocytochemical studies that sugges the sclerotized copulatory structures used to unite the group are nonhomologous among several taxa (Raikova et al., 2001) (citation). I propose leaving Childia groenlandica as the sole occupant of Childiidae and creating a new family, Actinoposthiidae, for the other childiid taxa." Hooge MD, Haye P, Tyler S, Litvaitis MK, Kornfield I 2002 (citation)- Phylogenetic relationships using 18S rDNA, and morphological characters of sperm and body-wall musculature.- "The unique nature of C. groenlandica led Hooge 2001 (citation) to remove the other species in the Childiidae to a new family, the Actinoposthiidae. The gene tree supports this taxonomic revision; however, some further changes may be necessary, inasmuch as members of the actinoposthiid genus Paraphanostoma also have circular muscles (Westblad, 1942) (citation)."
Return to Acoela Actinoposthiidae