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Citation for Study 411

Citation title: "Trochophore concepts: Evolution of larvae in polychaetes and other spiralians.".

This study was previously identified under the legacy study ID S361 (Status: Published).

Citation

Rouse G. 1999. Trochophore concepts: Evolution of larvae in polychaetes and other spiralians. Biological Journal of the Linnean Society, 66(4): 411-464.

Authors

• Rouse G.

Abstract

Trochophore is used in a strict sense for larvae having an opposed-band method of feeding, involving a prototroch and metatroch. Other ciliary bands such as a telotroch and neurotroch may be present. The trochophore has been proposed to represent the ancestral larval form for a group of metazoan phyla (including all members of the Spiralia). Trochophore is a name also often applied to larvae that do not conform to the above definition. A cladistic analysis of spiralian taxa (with special reference to polychaete annelids), based on a suite of adult and larval characters, is used to assess several hypotheses: (1) That the trochophore (in a strict sense) is a plesiomorphic form for the Spiralia; (2) That the strictly defined trochophore is plesiomorphic for members of the Spiralia such as the Polychaeta. The homology of each of the various separate ciliary bands of spiralian larvae, and features such as the apical tuft and protonephridia is also assessed. The results favour the conclusion that the trochophore, if defined as a feeding larval form using opposed bands, should not be regarded as an ancestral (= plesiomorphic) type for the Spiralia, or any other large taxon such as the Polychaeta or Mollusca. The evidence suggests that the various ciliary bands have differing evolutionary histories, and only the Echiura (possibly an annelid group) has members with the classical trochophore. The trochophore is re-defined as a larval form minimally with a prototroch. This broad definition covers a wide variety of larvae, and matches the current usage more accurately than the restricted term. Features such as the neurotroch, telotroch and opposed-band feeding show convergence and reversals. The nature of the metatroch requires further investigation. The presence of a prototroch (and hence trochophore larvae) is used to identify an apomorphy-based taxon, Trochozoa, that includes the first ancestor to have evolved a prototroch and all its descendants. This minimally includes the Annelida (sensu lato), Echiura, Entoprocta, Mollusca and Sipuncula and is a less inclusive taxon than the Spirali

Keywords

prototroch, metatroch, larval feeding, Polychaeta, Spiralia, Trochozoa, opposed-bands

External links

• DOI: 10.1111/j.1095-8312.1999.tb01920.x

About this resource

• Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S411
• Other versions: Nexus NeXML
• Show BibTeX reference

  		@ARTICLE{TreeBASE2Ref17274,
  	 author = {G. W.  Rouse},
  	 title = {Trochophore concepts: Evolution of larvae in polychaetes and other spiralians.},
  	 year = {1999},
  	 keywords = {prototroch, metatroch, larval feeding, Polychaeta, Spiralia, Trochozoa, opposed-bands},
  	 doi = {10.1111/j.1095-8312.1999.tb01920.x},
  	 url = {},
  	 pmid = {},
  	 journal = {Biological Journal of the Linnean Society},
  	 volume = {66},
  	 number = {4},
  	 pages = {411--464},
  	 abstract = {Trochophore is used in a strict sense for larvae having an opposed-band method of feeding, involving a prototroch and metatroch. Other ciliary bands such as a telotroch and neurotroch may be present. The trochophore has been proposed to represent the ancestral larval form for a group of metazoan phyla (including all members of the Spiralia). Trochophore is a name also often applied to larvae that do not conform to the above definition. A cladistic analysis of spiralian taxa (with special reference to polychaete annelids), based on a suite of adult and larval characters, is used to assess several hypotheses: (1) That the trochophore (in a strict sense) is a plesiomorphic form for the Spiralia; (2) That the strictly defined trochophore is plesiomorphic for members of the Spiralia such as the Polychaeta. The homology of each of the various separate ciliary bands of spiralian larvae, and features such as the apical tuft and protonephridia is also assessed. The results favour the conclusion that the trochophore, if defined as a feeding larval form using opposed bands, should not be regarded as an ancestral (= plesiomorphic) type for the Spiralia, or any other large taxon such as the Polychaeta or Mollusca. The evidence suggests that the various ciliary bands have differing evolutionary histories, and only the Echiura (possibly an annelid group) has members with the classical trochophore. The trochophore is re-defined as a larval form minimally with a prototroch. This broad definition covers a wide variety of larvae, and matches the current usage more accurately than the restricted term. Features such as the neurotroch, telotroch and opposed-band feeding show convergence and reversals. The nature of the metatroch requires further investigation. The presence of a prototroch (and hence trochophore larvae) is used to identify an apomorphy-based taxon, Trochozoa, that includes the first ancestor to have evolved a prototroch and all its descendants. This minimally includes the Annelida (sensu lato), Echiura, Entoprocta, Mollusca and Sipuncula and is a less inclusive taxon than the Spirali}
  }
  		

• Show RIS reference

  		TY  - JOUR
  ID  - 17274
  AU  - Rouse,G. W. 
  T1  - Trochophore concepts: Evolution of larvae in polychaetes and other spiralians.
  PY  - 1999
  KW  - prototroch
  KW  - metatroch
  KW  - larval feeding
  KW  - Polychaeta
  KW  - Spiralia
  KW  - Trochozoa
  KW  - opposed-bands
  UR  - http://dx.doi.org/10.1111/j.1095-8312.1999.tb01920.x
  N2  - Trochophore is used in a strict sense for larvae having an opposed-band method of feeding, involving a prototroch and metatroch. Other ciliary bands such as a telotroch and neurotroch may be present. The trochophore has been proposed to represent the ancestral larval form for a group of metazoan phyla (including all members of the Spiralia). Trochophore is a name also often applied to larvae that do not conform to the above definition. A cladistic analysis of spiralian taxa (with special reference to polychaete annelids), based on a suite of adult and larval characters, is used to assess several hypotheses: (1) That the trochophore (in a strict sense) is a plesiomorphic form for the Spiralia; (2) That the strictly defined trochophore is plesiomorphic for members of the Spiralia such as the Polychaeta. The homology of each of the various separate ciliary bands of spiralian larvae, and features such as the apical tuft and protonephridia is also assessed. The results favour the conclusion that the trochophore, if defined as a feeding larval form using opposed bands, should not be regarded as an ancestral (= plesiomorphic) type for the Spiralia, or any other large taxon such as the Polychaeta or Mollusca. The evidence suggests that the various ciliary bands have differing evolutionary histories, and only the Echiura (possibly an annelid group) has members with the classical trochophore. The trochophore is re-defined as a larval form minimally with a prototroch. This broad definition covers a wide variety of larvae, and matches the current usage more accurately than the restricted term. Features such as the neurotroch, telotroch and opposed-band feeding show convergence and reversals. The nature of the metatroch requires further investigation. The presence of a prototroch (and hence trochophore larvae) is used to identify an apomorphy-based taxon, Trochozoa, that includes the first ancestor to have evolved a prototroch and all its descendants. This minimally includes the Annelida (sensu lato), Echiura, Entoprocta, Mollusca and Sipuncula and is a less inclusive taxon than the Spirali
  L3  - 10.1111/j.1095-8312.1999.tb01920.x
  JF  - Biological Journal of the Linnean Society
  VL  - 66
  IS  - 4
  SP  - 411
  EP  - 464
  ER  -