Geographic distribution: Circumpolar, Groenland, Iceland, Baltic Sea, West Coast US, Woods Hole, US Mediterranean; 0-50 meters in plankton, algae, shallow water in sand, mud, etc. Levinsen GMR 1879 (citation)- described species as Convoluta groenlandica, illustration of seminal vesicle and penis, occurs in Greenland. p 168 "Body broad, anterior obtusely rounded. Lateral part enrolling beginning a little behind the anterior part of the body, to the extended third of the body. Color pale reddish violet. Otoliths in anterior part of the body. Many follicular testes located in anterior part of body. In posterior part 2 egg shaped sacks in each of which is a small seminal vesicle and a penis chitinous and striated (so that it appears composed of many pointed spines) and pointed, forming a little curve. Ovaries and yolk glands associated are located in middle part of the body." Length 2-21/2 mm Graff L v 1882 (citation)- brief discussion as Convoluta groenlandica. "length 2-2.5 mm, quite broad and rounded anterior behind a little pointed. The enrolling of sides begins behind the anterior end and reaches to the last third of the body. Color a bright violet-red, produced by a quantity of violet red flects. In anterior (each side of the mouth?) two vesicles with slightly bent, lon striped chitinous stylets. Levinsen makes a contractiction to his Daneish descritpion in the Latin diagnosis, then vesicles be in "posteriore parte": I takes this last statement to be a mistake in writing and also the conclusion that the vesicles contain sperm for an error. In my opinion we have to do here with a "giftorgan", similar to that of Convoluta paradoxa." Habitat and distribution- between algae and detritus under the surface- coast of Greenland. Bohmig L 1895 (citation)- lists as Convoluta p 44. Graff L v 1904 (citation)- mention of Convoluta groenlandica p 209 note. Graff L v 1910 (citation)- lists from Woods Hole. Luther A 1912 (citation)- one specimen only from Bay of Finland- gives detailed histology. Steinbock O 1931 (citation)- agrees baltica and spinosa should be groenlandica. Steinbock O 1932 (citation)- lists the following references: Levinsen 1879 p 168 H Sabussow 1897, p 14 C. borealis and C. convoluta E Van Hoffen 1897, p 225 [lists names only] L v Graff 1905, p 25 E. Wesenberg-Lund 1925, p 41 [lists names only] O. Steinbock 1931, p 2. in check list for Arctic p 298 and in table p 335. Bresslau E 1933 (citation)- p 62, figure 36 from Luther an illustration of sensor hairs in this species. Steinbock O 1933 (citation)- notes, occurence in Rovigno, notes only in colder weather here? see also Steinbock O 1938 paper. He was surprised to find it in Rovigno, maybe here only in cold months- why did other researchers not see it? Found Zoochlorella in it. Noted a dark middle stripe on one. Lists from a variety of habitats, sandy, mud, shelly, etc, mostly 10-25 meters deep. agrees baltica and spinosa should be groenlandica. Steinbock O 1938 (citation)- from Iceland- probably found only in winter, also notes it is reported from Faroes, Gulf of Finland, Adriatic Sea (ROvigno), Woods Hole, West Greenland, the Faroes Island of Hven- the sound. Meixner J 1938 (citation)- p 74, figure 75. footnote on spinosa and groenlandica. Westblad E 1940 (citation)- subtidal form he points out, etc. comparison to other species. Karling TG 1940 (citation)- mentions p 137. Westblad E 1945 (citation)- description and illustration, fairly complete. p 31-37, figures 15, 16, 17. definition p 51-52. says he agrees with Meixner (1925) and Steinbock (1931) that species should be groenlandica and synonyms are C. spinosa and C. baltica. occurence: generally present on west coast of Scandanavia in blank mud (often anaerobic) of bays (to 40 m deep in "mud") - to eye is white to red, under microscope ar echaracteristic orange red packets of rhabites. shape: on fixation anterior end is rolled under- so characteristics can be picked out by it. epithelial gland cells: he disagrees with Luther they are well developed dorsally (not ventrally) and ventral only behind the mouth if at all. nervous system: brain an arc lying on dorsal side of statocyst (figures 15-16, p 32-33)- partially encloses statocyst. describes nerves, etc p 32-33. postcerebral organ- gland cells behind brain [appear attached to brain] erythrophile cells granular. female reproductive organ- female ovary in 2 parts- anterior with egg mother cells and oocytes is reticular posterior with ripe eggs arrayed one behind the other. male reproductive organ- copulatory organ in general he agrees with Luther's account. Penis stylet is composed of 15-20 cuticular needles (not a long ? tube as Graff said)- near point needles are so close together as to appear united. Penis is filled with secretion which is result of degeneration of epithelium of the duct between the seminal vesicle and the penis- this epithelium is low in proximal part of seminal vesicle and high in distal part so at to narrow the duct farther along cells ? Marcus E 1947 (citation)- p 160 mentions. Westblad E 1948 (citation)- p 14 glands in, p 19. In key p 55-56. Ferguson FF, Jones ER 1949 (citation)- list from Norfolk Peninsula. Marcus E 1950 (citation)- notes synonomy same as Hyman 1959, p 9, 102. Hyman LH 1951 (citation)- vol 2, p 77 notes muscle fibers in epithelial layer. Marcus E 1952 (citation)- mentions p 10. Westblad E 1954 (citation)- reports it "common on mud bottom (to 10-12 meters) but no mass occurences in several localities in Norway- gives occurence- North Atlantic form Greenland and North America, Scandinavian Coast, Baltic to Gulf of Finland, British Coasts, Adrea:Roving. Hyman LH 1959 (citation)- discusses and lists synonyms as follows: Convoluta groenlandica Levinsen 1879 Childea spinosa Graff 1911 Childea baltica Luther 1912 Childea groenlandica Meixner 1925 Some turbellaria from the Coast of California, American Museum Novitales No 1943- June 17, 1959. p 2-5 and figure 1-7 description and discussion. Luther A 1960 (citation)- lists synonym as in Hyman 1959, good illustration and brief description. Ax P 1961 (citation)- notes polygonal epithelial cells of, p 8. Ax P 1963 (citation)- ?receptors in, illustration from Levinson. [Bush 1963]- notes some specimens thought to be this species collected on algae at Woods Hole, summer 1963- Steinbock O 1967 (citation)- mentions p 397. Dorjes J 1968 (citation)- p 111 lists as type of genus. Henley C 1968 (citation)- Costello DP, Henley C, Ault C 1969 (citation)- electron microscopy studies of sperm [Bush: but this is my Neochildia fusca]. Ultrastructure of sperm flagella in this speices. References to other work on flatworms. Beklemischev VN 1969 (citation)- Vol II, p 150, illustron of sensory cells in - illustration p 394 on pyriform organs and stylets in reproductive system, illustration 396- but note ? in gonapore- calls it female". Boyer BC 1971 (citation)- on embryology of sprial cleavage [Bush: but this is my Neochildia fusca] Hendelberg J, Hedlund K-O 1973 (citation)- electron microscopy on spermatozoa. 9 + 1 axonemes. Hendelberg J, Hedlund K-O 1974 (citation)- electron microscopy on ciliary rootlet system. Henley C 1974 (citation)- electron microscopy studies of sperm [Bush: but this is my Neochildia fusca] Hendelberg J 1974 (citation)- on ciliary rootlet system. Karling TG 1974 (citation)- mentions p 65. in list p 9, in key p 12, illustration p 13, ecology of p 26, 63, 64, 78, 84 description p 36. Dorjes J, Karling TG 1975 (citation)- Swedish Museum of Natural History, notes occurence in plankton many places in world- Notes Riser collected in plankton in New Orleans in June 1973. Crezee M 1975 (citation)- interconnection of rootlets of cilia, p 840. Hendelberg J 1981 (citation)- p 240 on ciliary rootlets, electron microscopy. [Bush 1984]- collected 2 specimens in March at Penzance Rd, Woods Hole. [Bush- notes that experiments in references below were actually perfomed on Neochildia fusca instead of CHildea groenlandica (personal communication):] Henley C 1968 (citation) Costello DP, Henley C, Ault C 1969 (citation) Boyer BC 1971 (citation) Hooge MD 2001 (citation)-
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.
Reuter M, Raikova OI, Gustafsson MKS 2001 (citation)- Phylogeny, neurons, muscles. Acoela and Nemertodermatida
studies of neuroanatomy. Species used include:
Catenulida
Stenostomum leucops Duges 1828
Macrostomida
Macrostomum lineare Muller 1774
Acoela
Anaperus biaculeatus Boguta 1970
Childia groenlandica Levinsen 1879
Faerla glomerata Westblad 1942
Paraphanostomum crassum Westblad 1942
Avagina incola Leiper 1902
Nemertodermatida
Nemertoderma westbladi Steinbock 1938
Mera stichopi Westblad 1949
Raikova OI, Reuter M, Kotikova EA, Gustafsson MKS 1998 (citation)- 5-HT immunoreactivity in Acoela, brain analysis. Species used: Anaperus biaculeatus, Childia groenlandica, Actinoposthia beklemischevi, and Mecynostomum sp.
Lundin K 1997 (citation)- "ultrastructure of the epidermal ciliary rootlets and associated structures in species of the Nemertodermatida and Acoela". Species used: Meara stichopi, Nemertoderma westbladi, Nemertoderma cf. bathycola, Convolutriloba retrogemma, Childia groenlandica, Paraphanostoma submaculatum, Haploposthia virdis.
Reuter M, Raikova OI, Gustafsson MKS 1998 (citation)- brain of Acoela a common flatworm type? Immunocytochemical study (FMRF-amide) of nervous system of four species: Anaperus biaculeatus, Childia groenlandica, Actinoposthia beklemischevi and Mecynostomum sp.
Stricker SA, Welford AM, Morris CA 1992 (citation)- "Somatic cell-oocyte interactions during oogenesis in the acoel flatworm Childia groenlandica."
Dorjes J, Karling TG 1975 (citation)- p 178 notes that Graff L v 1911 (citation)- p 21, "has seen specimens of C. groenlandica 'frei im Wasser schwimmend'". Also they note that specimens from New Orleans, "collected in June 1973 by Nathan W. Riser, are easily identified by their paired cuticular penis stylets. According to Riser 'the specimens were very abundant in plankton'".
Notes from synonyms
Notes for Childia pansa
Marcus E 1950 (citation)- describes this species and compares with groenlandica. This species has no frontal organ, scarcity of cutaneous glands and the position of the ovaries which is level with the mouth- p 8-10, figures 8 and 9, p 102. lightly compressed animal, broadly rounded at anterior and ? at posterior end where copulatory organs are - length 0.625 mm when not compressed- compressed to 0.4 mm anterior end may enroll ventrally- colorless. Statocyst at end of anterior 1/5th, mouth a little before the middle of ventral side- slightly concave at anterior end, convex dorsally. Swims smoothly without ?- taste hairs at anterior end. cilia- 6 microns at anterior- 8-9 microns at posterior- epithelium with sunken nuclei some cross walls can be seen. Cutaneous glands few scattered on ventral side- compares to C. groenlandica, no frontal organ but animal appears to have an opening- gland cells were pulled away or did not stain- at any rate a frontal organ not present- see summary p 102. muscles- similar to those of C. groenlandica ectocytium- a layer with nuclei and vacuoles- vacuoles separate the ectocytium and the endocytium- endocytium with diatoms- mouth, etc. reproductive organs- testes dorsolateral at level of brain- to each side and backwards spermatozonia are arrayed various stages of spermatogenesis- on each side runs a string of sperm toward seminal vesicles which are not completely spherical due to flattening of posterior end- penis structure as in groenlandica- stylet 0.045 mm (compared to 0.068 Graff ) of cuticular fibers surrounding the ejactus ductus. Male atrium which Westblad called the "Penisscheide" is muscular- atrium glands present. Female ovary- distinctly different from groenlandica- ? place the germinatic zone a little anterior to the brain. In C. pansa however they begin at level of mouth, specimen lacked mature eggs- germinative layer is in middle of body and oocytes diverge to each side. occurence- in mud of Bertioga, near Santos where tide and salinity shift 4 times in 24 hours. "closely related to only other species of the genus C. groenlandica. Notwith- standing pansa must be separated because it has no frontal organ- not even isolated glands were seen- the cutaneous glandds are scarce and the germ zones of the ovaries lie at the level of the mouth that is a little behind the middle of the body." Ax P 1961 (citation)- notes cellular epidermis. Dorjes J 1968 (citation)- lists. Dorjes J, Karling TG 1975 (citation)- list as synonym of Childia groenlandica.