Dalytyphloplanida is a suborder of rhabdocoel flatworms. It contains about 1000 species and has a cosmopolitan distribution in both marine and freshwater environments, with several groups having commensal or parasitic lifestyles.[1]

Dalytyphloplanida
Strongylostoma elongatum spinosum.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Platyhelminthes
Order: Rhabdocoela
Suborder: Dalytyphloplanida
Willems, Wallberg, Jondelius, Littlewood, Backeljau, Schockaert & Artois, 2006
Subdivisions

Description

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The suborder Dalytyphloplanida was recently erected based on molecular evidences and few synapomorphies are known. The possible identified synapomorphies include the presence of small dense granules, as well as an axonemal spur and a group of longitudinal microtubules in sperm cells.[1]

Classification

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Traditionally, members of the suborder Dalytyphloplanida were classified into two groups: Dalyellioida and Typhloplanoida, although both were poorly characterized morphologically.[1] Recent molecular studies revealed that those two groups were not separated clades and both were merged in the clade Dalytyphloplanida.

Within Dalytyphloplanida two clades were found: Neodalyellida, formed by marine species of the former group Dalyellioida, some of which are parasites, and Neotyphloplanida, which includes a clade of marine species of the former Typhloplanoida (Thalassotyphloplanida) and one of freshwater species (Limnotyphloplanida).[2] However, synapomorphies for these newly erected clades are not yet known.

References

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  1. ^ a b c Willems, Wim R.; Wallberg, Andreas; Jondelius, Ulf; Littlewood, David T. J.; Backeljau, Thierry; Schockaert, Ernest R.; Artois, Tom J. (2006). "Filling a gap in the phylogeny of flatworms: relationships within the Rhabdocoela (Platyhelminthes), inferred from 18S ribosomal DNA sequences". Zoologica Scripta. 35 (1): 1–17. doi:10.1111/j.1463-6409.2005.00216.x. hdl:1942/1609. ISSN 0300-3256. S2CID 85917387.
  2. ^ Fontaneto, Diego; Van Steenkiste, Niels; Tessens, Bart; Willems, Wim; Backeljau, Thierry; Jondelius, Ulf; Artois, Tom (2013). "A Comprehensive Molecular Phylogeny of Dalytyphloplanida (Platyhelminthes: Rhabdocoela) Reveals Multiple Escapes from the Marine Environment and Origins of Symbiotic Relationships". PLOS ONE. 8 (3): e59917. doi:10.1371/journal.pone.0059917. ISSN 1932-6203. PMC 3607561. PMID 23536894.