Turbellarian taxonomic database

Acoelomorpha Nemertodermatida


Habitat:  
        Flagellophora apelti- sublittoral to 80m North Sea & Adriatic.
        Nemertoderma- sublittoral, Steinbock O 1930 fine mud at 250m.
        Meara- intestine of Stichopus tremulus or in cavity of body?

Outer Appearance:
       Size:  Flagellophora- 0.8-1.2 mm
                 Meara- up to 3mm

Integument:  Flagellophora & Meara - polygonal cells at base of cilia & 
                    deeper ep. cells.  Meara thick, cellular.   
             Nemertoderma- thick epithelial with vacuoles.
             Meara- outer circ., inner longitudinal muscles, 
                                 only small adenal glands
Nervous System:
      Flagellophora- internal- high brain in cross section.
      Meara- neuropile at base of intestinal cells (like Nemertoderma),
             swellings for 2 dorsolateral nerves- no inner nervous system
             and brain less dev than Nemertoderma.
Statocyst: 
      2 statoliths.  Statocyst muscles go out to longitudal muscles?
              Steinbock O 1930 plate I.  
      Meara no statocyst muscles.
      Meara & Nemertoderma statocyst - only sense organ.

Digestive Tract:
      Flagellophora- no pharynx or mouth.  "Koernerkolben" cells = mucous cells.  Flagella organ.   		
      Nemertoderma bathycola- Steinbock O 1930- refer to mouth at front end [= male pore]
      Riedl RJ 1960 (citation)- defines with ventral mouth.
      Karling TG 1974- shows ventral mouth.
      Karling TG 1967 (citation)- illustration of sections to show cilia in digestive tract.
	Karling TG 1967 (citation)- p 5,6, & 8 on gut.					
      Nemertoderma rubra- Faubel A 1976 (citation)- "typical pharynx simplex". 
    		[glands and mouth are Koernerkolben?] no? but there are ones in digestive tract.
        		
	Meara- fleshy lips a little behind middle of ventral side and thickened neuropile for a sort of 
		psuedo-pharynx  (Westblad E 1948 (citation)) intestine all through body with short 
		sub-lateral side ventricles. epithelial lining sort of cells- amoeboid cells 
		  and "Koernerkolben"

Reproductive System:  Faubel A 1983 (citation)- notes ciliated male tract (p. 26).

	Flagellophora (female)- ovary- large bursa opening dorsally?
	Meara (female)- ovary follicular- fills posterior part of bady.

	Flagellophora (male)- ventral male pore- copulatory organ thickened and interal part of epithelial 
		layer and gland cells. no seminal vesicles- or antrum.
	Meara (male)- testis follicular and fills (??) part of body.  seminal vesicles thin walled (??). 	

	Copulation by insemination - also spermatophores.

	Spermatozoa- uniflagellate- see Tyler S, Rieger RM 1975 (citation) and Tyler S, Rieger RM 1977 (citation)
		Hendelberg J 1977 (citation)- Nemertoderma- sp uncertain and Meara p 152, all have
		middle piece and tail (uniflagellate).
		both "modified spermatozoa" Franzen A 1956 (citation), Franzen A 1977 (citation) 
		"evolved from pimitive type of metazoan spermatozoa."  helically coiled 
		middle piece in Meara etc- primitive single flagellum etc- differs from Acoela
		see Hendelberg J 1977 (citation).								

Ax 1961 (citation)-  Discusses separation of this order from Acoela p 47 in diagram p 45.
Faubel A, Dorjes J 1978 (citation)- definition p 8.
        "Archoophora with a digestive tract containing "Koernerkolben" cells, mouth opening simple,
        nervous system epithelial aor subepithelial, statocyst with two or more statoliths, excretory
        organ unknown, male genital pore in the posterior part of the body, uniflagellate spermatozoa."

Karling TG 1974 (citation)- discussion of the phylogeny of Turbellaria (See under Nermertoderma)
Rieger RM 1981 (citation)- on electron microscopy structure p 216, sperm 222, statocyst 220-221.
Doe DA 1981 (citation)- pharynges discussion.


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


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.


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.


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.


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.


Bush LF 1981 (citation)-  Marine flora and fauna of the northeastern United States. Turbellaria: Acoela and
Nemertodermatida.


Tyler S, Rieger RM 1977 (citation)- "Ultrastructural evidence for the systematic position of the
Nemertodermatida
(Turbellaria)."


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.  


Jondelius U, Ruiz-Trillo I, Baguna J, Riutort M 2002 (citation)- "The Nemertodermatida are basal bilaterians not
members of Platyhelminthes."


Reuter M, Raikova OI, Jondelius U, Gustafsson MKS 2000 (citation)- "The brain of the Nemertodermatida
(Platyhelminthes) as revealed by anti-5HT and anti-FMRFamide immunostainings."  Species: Meara stichopi,
Nemertoderma westbladi.


Lundin K, Sterrer W 2001 (citation)- Diagnosis of the Order Nemertodermatida.  p 27 "Present structural,
immunocytochemical and embryological evidence favours the idea that the Nemertodermatida and Acoela are sister
taxa....".


Lundin K, Hendelberg J 1998 (citation)- "Is the sperm type of the Nemertodermatida close to that of the
ancestral Platyhelminthes?"


Lundin K 2000 (citation)-"Phylogeny of the Nemertodermatida (Acoelomorpha, Platyhelminthes). A cladistic
analysis."


Sterrer W 1998 (citation)- "New and known Nemertodermatida (Playthelminthes-Acoelomorpha) -- a revision."

Tyler S, Rieger RM 1977 (citation)- "Ultrastructural evidence for the systematic position of the Nemertodermatida
(Turbellaria)."