History, classification schemes, and characters: Orsted AS 1842 (citation). Claparede E 1861 (citation)- description of Convoluta paradoxa and discussion of grouping. Uljanin W 1870 (citation)- Tribe Acoela Uljanin 1870 as in Leuckart 1871- definition p 460-1. Graff L v 1878 (citation)- notes Uljanin's use of term acoele. Jensen OS 1878 (citation)- Classification of acoela and other groups. Graff L v 1882 (citation)- definition. Wagner F v 1891 (citation)- revises Graff's monograph of 1891 and quotes his classification. Verrill AE 1893 (citation)- p 507-508- description of acoela but no "diagnosis". Graff L v 1904 (citation)- revised definition as Subclass, descusses phylogeny, and systematics. Bohmig L 1908 (citation)- p 3. Graff L v 1911 (citation)- key to genera for Order Acoela. Luther A 1912 (citation). p 51. Key to genera of Acoels. Says this is a provisional arrangement. Discussion of relationship between the genera and comparison with Graff's arrangement. Wilhelmi J 1913 (citation)- p 11-12 classification, definition p 12, p 95 excretory system. Peebles F 1915 (citation)- suggests classification of acoela might better be based on presence or absense of bursa seminalis, rather than on number of gonapores, etc. p 303, 310. Steinbock O 1930 (citation)- p 79 changes definition of Acoela to include Nemertodermatidae. An der Lan H 1936 (citation)- classification with placement of new genera. Karling TG 1940 (citation)- p 230 definition (=Acoela Uljanin 1870). Also, mentions p 223-225, 228. Marcus E 1947 (citation)- reference p 159. Marcus E 1948 (citation)- reference p 112, mentions p 126. Westblad E 1948 (citation)- classification, p 59 phylogeny, p 65 definition. Marcus E 1949 (citation)- reference p 8. Marcus E 1950 (citation)- reference p 6, mentions p 35 Marcus E 1951 (citation)- lists p 7-8. Hyman LH 1951 (citation) -vol 2, p 127 discussion of Acoela, lists general characters. p 175 embryology in Acoels, other characteristics p 128, 131, 182, 193, 203. Marcus E 1952 (citation)- lists references p 7. Marcus E 1954 (citation)- lists p 420. Beauchamp P de 1961 (citation)- classification. Hanson ED 1963 (citation)- on ciliate acoel homologies and evolutionary history of descent and origin of Metazoa. Lumsden RD 1966 (citation)- Excretion by Acoels. Steinbock O 1966 (citation)- On divisions of Acoels, p 139. Dorjes J 1968 (citation)- Classification of 15 Families of Acoels. Leuckart 1871 (citation)- reference to Uljanin W 1870 (citation). Karling TG 1974 (citation)- key p 12. discussion of phylogeny. Characters p 7-8. Tyler S 1976 (citation)- relationships as shone by ultrastructure. Adhesive glands, p 56, not "duo-gland type" as in other Turbellaria. Ax P 1977 (citation)- on life cycles in p 13, 18. Rieger RM 1981 (citation)- on electron microscopy structure p 216, rhabdites p 219, sperm 223, statocyst 220-221. Boaden PJS 1981 (citation)- Oxygen requirements of acoela. Doe DA 1981 (citation)- pharynges discussion. Faubel A 1983 (citation)- a ciliated male tract in the genus Haploposthia, p 26.
Ruiz-Trillo I, Paps J, Loukota M, Ribera C, Jondelius U, Baguna J, Riutort M 2002 (citation)- "phylogenetic analysis of DNA sequences from the myosin heavy chain type II (myosin II) gene from a large set of metazoans, including acoels and nemertodermatids." Evolutionary significance.
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
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
Reuter M, Raikova OI, Jondelius U, Gustafsson MKS, Maule AG, Halton DW 2001 (citation)- Immunocytochemical study of Faerlea glomerata, Avagina incola, and Paraphanostoma crassum to look at the organization of the Acoela nervous system.
Littlewood DTJ, Olson PD, Telford MJ, Herniou EA, Riutort M 2001 (citation)- Reviews recent molecular systematics on Acoela, Nemertodermatida, Catenulida and Rhabditophora, EF1 analysis and its limitations, etc.
Gschwentner R, Ladurner P, Nimeth K, Rieger R 2001 (citation)- stem cells (neoblasts) analysis in stages of cell cycle in Convolutriloba longifissura. Relation to reproduction and regeneration. Importance in phylogenetic relationships.
Akesson B, Gschwentner R, Hendelberg J, Ladurner P, Mueller J, Rieger R 2001 (citation)- "new pattern of reproduction in the Acoela has prompted us to review the various ways by which asexual reproduction occurs in the group." Type of fission of Convolutriloba longifissura is described. Evolutionary significance.
Tyler S, Hyra GS 1998 (citation)- muscle patterns in Acoela, including the following taxa: Anaperus, Childia groenlandica, Convoluta pulchra, Mecynostomum, Otocelis, Paedomecynostomum bruneum, Paratomella , Pseudaphanostoma.
Berney C, Pawlowski J, Zaninetti L 2000 (citation)- "Elongation factor 1-alpha sequences do not support an early divergence of the Acoela". Following species used: Convoluta roscoffensis, Crenobia alpina, Girardia tigrina, Leptoplana tremellaris, Prostheceraeus vittatus, Schmidtea polychroa.
Ruiz-Trillo I, Riutort M, Littlewood DTJ, Herniou EA, Baguna J 1999 (citation)- "Acoel flatworms: earliest extant bilaterian metazoans, not members of Platyhelminthes".
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.
Gradinger R, Schnack-Schiel SB 1998 (citation)- "sympagic acoel turbellarians" effect of Antarctic Polar ice and salinity on mortality compared to species of copepods.
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.
Katayama T, Yamamoto M, Wada H, Satoh N 1993 (citation)- Phylogeny of Acoels "inferred from partial 18S rDNA sequences". Species used in analysis: Convoluta naikaiensis Yamasu 1982, Amphiscolops sp. Yamasu, Notoplana koreana Kato 1937, Planocera multitentaculata Kato 1944, Stylochus orientalis Bock 1913, Pseudostylochus obscurus (Stimpson 1857), Stylochoplana pusilla Bock 1924, Thysanozoon brocchii (Risso 1818), Dendrocoelopsis lactea Ichikawa & Okugawa 1958 and Dugesia japonica Ichikawa & Kawakatsu, 1964.
Ehlers U (citation)-"Frontal glandular and sensory structures in Nemertoderma (Nemertodermatida) and Paratomella (Acoela): ultrastructure and phylogenetic implications for the monophyly of the Euplathelminthes". Nemertoderma sp. B, and Paratomella rubra used.
Raikova OI 1991 (citation)- fine structure, "nervous system and ciliary receptors of acoelan turbellarians". Species considered: Actinoposthia beklemischevi, Anaperus biaculeatus, Aphanostoma virescens, Haploposthia opisthorchis.
Bedini C, Lanfranchi A 1991 (citation)- Electron microscopy study of "central and peripheral nervous system of Acoela"
Winsor L 1990 (citation)- Key to "free-living" marine turbellaria of north Queensland, Australia. Also, new
species and taxonomic revisons. Key to free-living acoels for Australia. Species and taxa include:
Waminoa litus
Convolutriloba Henelberg and Akesson 1988
Convolutriloba hastifera
Convolutriloba japonica (Kato 1951)
Convolutriloba cf. retrogemma
Amphiscolops
Amphiscolops australis
Wulguru cuspidata
Heterochaerus sargassi (Hyman 1939)
Heterochaerus australis Haswell 1905
Reuter M, Lehtonen M, Wikgren M 1988 (citation)- "Immunocytochemical evidence of neuroactive substances in flatworms of different taxa - a comparison." Species Archiloa unipunctata, Gyratrix hermaphroditis, Microdalyellia fusca, Polycelis nigra, Promesostoma marmoratum, Typhloplana viridata.
Smith JPS, Tyler S 1985 (citation)- "The acoel turbellarians: kingpins of metazoan evolution or a specialized
offshoot?" Look at ultrastructural characters (body wall, parenchyma, digestive tract). "....it appears
that acoels are derived, and cannot logically be fitted into any of the current theories of interphyletic
relationships, either as models of primitiveness or as reduced coelomates. Instead, the Nemertodermatida,
sister group to the Acoela, and the Catenulida appear more primitive, and consideration of these groups for
phylogenetic schemes is more likely to bear fruit." Species of Acoela include:
Diopisthoporus cf. longitubus
Diopisthoporus sp. (= Diopisthoporus gymnopharyngeus Smith JPS, Tyler S 1985 (citation))
Hesiolicium inops
Convoluta convoluta
Convoluta sp. nov. (= Convoluta pulchra Smith JPS, Bush L 1991 (citation))
Oxyposthia praedator
Oligochoerus limnophilus
Paedomecynostomum sp.
Paramecynostomum diversicolor
Anaperus biaculeatus
Anaperus sp.
Kuma sp.
Philactinoposthia sp.
Otocelis luteola
Faubel A, Regier S 1983 (citation)- "Anatomy and taxonomy of new Acoela (Turbellaria) from the sublittoral of the northern North Sea."
Bush LF 1981 (citation)- Marine flora and fauna of the northeastern United States. Turbellaria: Acoela and Nemertodermatida.
Powell EN 1979 (citation)- "Biochemical adaptations to long-term sulfide stress present in the interstitial metazoans of the sulfide system."
Mamkaev YuV, Markosova TG 1979 (citation)- "Electron microscopic studies of the parenchyma in some representatives
of the Acoela." Species studied include:
Oxyposthia praedator
Convoluta convoluta
Anaperus biaculeatus
[translated summary "...differentiation of the secretory cells of the epidermal glands in the parenchyma,
and the presence of muscular and nervous elements in the epidermal layer, leads to the conclusion that in the
Acoela there is a close interrelation between the parenchyma and the epidermis, and that phagocytoblast and
kinoblast are still poorly separated."]
Mamkaev YuV, Kostenko AG 1991 (citation)- "On the phylogenetic significance of sagittocysts and copulatory organs in acoel turbellarians."
Raikova OI 1989 (citation)- Ultrastructure of the nervous system and the sensory receptors of acoel turbellarians. [In Russian]"
Carranza S, Baguna J, Riutort M 1997 (citation)- "Are the Platyhelminthes a monophyletic primitive group? An assessment using 18S rDNA sequences." Looks at Rhabditophora, Acoela, Catenulida. Species of Turbellaria used include the following: Crenobia alpina, Dendrocoelum lacteum, Monocelis lineata, Archiloa rivularis, Geocentrophora sp., Mesocastrada sp., Nemertinoides elongatus, Urastoma sp., Macrostomum tuba, Microstomum lineare, Discocelis tigrina, Planocera multitentaculata, Stenostomum leucops, Convoluta pulchra, Convoluta naikaiensis. New sequences reported for many of these species.
Reuter M, Lehtonen M, Wikgren M 1988 (citation)- "Immunocytochemical evidence of neuroactive substances in flatworms of different taxa--a comparison." Species studied: Acoela sp., Archiloa unipunctata, Polycelis nigra, Microdalyellia fusca, Promesostoma marmoratum, Typhloplana viridata, Gyratrix hermaphroditus.
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