Geographic distribution: Circumpolar, North Atlantic, North Pacific (West Coast USA), Mediterranean plankton, shallow water. Graff L v 1910 (citation)- in species list for U.S. gives this a new genus- with brief definition. Graff L v 1911 (citation)- gives definition of genus which is really description of the species spinosa. "Proporidae without seminal bursa and without a chitinous nozzle. The mouth lies behind the middle on the ventral side, a pharynx is lacking. With paired penes- The 2 penes are provided with chitinous stylets. The frontal glands are loosely arrayed anterior to the brain. The testes form scatteered follicles. The genital opening lies at the posterior end of the body. Body flat with enrolling sides. 1 species known." Meixner J 1925 (citation)- footnote p 333, Childia baltica. Westblad E 1940 (citation)- mentions Childia often in making comparisons. Westblad E 1942 (citation)- on muscle layers in Childia and other genera -p 16. Cilia, ciliary roots, 5-6 microns thick homogeneous layers, then a layer of longitudinal muscles. Westblad E 1945 (citation)- definition p 50. Westblad E 1946 (citation)- note on sense organs p 24, taste organ in some Convoluta as in Childia (see Luther 1912) - probably same as Graff called glands in Convoluta sordida. Westblad E 1948 (citation)- p 56 in key, p 55 in definition of Tribe Opisthandropora-Abusalia- this is an exception to weakly cuticularized stylet. p 11 note orange red color; p 13 regeneration cells in epithelium of; p19 muscles in; p 23 brain in; p24 diagram of nervous system in; p 26 sense organs in- notes nerve cells in epithelium; p 38 stylet in copulatory organ; p 20 retractor muscles in anterior end; p 31 notes short sperm cells in; p 35 discussion of structure of copulatory organs here and then derivation from a simpler type [in his discussion there is no male antrum- just the end of the ejactus ductus- he implies separate male pore??] Beklemischev VN 1929 (citation)- says glands around reproductive organs make a series of rods to form a hollow tube. Marcus E 1949 (citation)- mentions cilia in p 34. Beauchamp P de 1961 (citation)- lists Childia in Family Haploposthiidae. Mamkaev YuV 1965 (citation)- says copulatory organ in this and Actinoposthia same but here only. Dorjes J 1968 (citation)- p 111, definition of genus- lists 2 species: C. groenlandica Levinsen 1879 and C. pansa Marcus 1950 Beklemischev VN 1969 (citation)- Vol II, p 85 notes nervous system not primitive, has "endon" Henley C 1974 (citation)- references to Childea here are really to Neochildia fusca. p 335 refers to Steinbock (1967) on regeneration in. Karling TG 1974 (citation)- mentions p 77.
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)."
Notes for the valid (accepted) taxonomic name
Return to Childiidae Childia