Taxon Relationships Discussion
TCS was developed primarily to allow the exchange of taxonomic concepts and names rather than to specify the best way to represent taxonomic names and concepts. This has meant that the majority of elements in TCS are optional to allow for the variety of different approaches to defining and recording taxonomic names and concepts.
During the development of TCS there was considerable discussion on what relationships should be modelled. The proposals have varied from an enumerated likst of any relationship that we ever found in any data sets through to a restricted list of relationships with no inverses and with which you could reason over.
In addition the way relationships are modelled in TCS vary.
-TaxonName Relationships are explicitly enumerated as properties of TaxonNames?
-TaxonConcept Relationships can be made in 2 distinct places: (1) as an integral part of the structure, and (2) separate from TaxonConcepts? under . Sometimes the latter are called "Third-Party-Relationships."
If a taxonomist wishes to make a relationship to another concept an integral part of a new concept definiton, including parent-child relationships and relationships to earlier, external concepts to nail down the meaning of the new concept, these relatioships should be described in (1) TaxonConceptRelationships. Example: Ranunculus abortivus L. sec. Kartesz (2004) “is congruent to” Ranunculus abortivus L. sec. FNA (1997), where Kartesz (2004) places this relationship into the definition to indicate that the newly published 2004 concept is defined by its relationship to the FNA 1997 concept.
If an expert asserts relationships between two concepts that were both authored at an earlier time, then by default these assessments are allocated to place (2),TaxonRelationshipAssertions i.e. outside the section. Example: Brachycerinae sec. Kuschel (1995) “includes” Brachycerinae sec. Marvaldi & Morrone (2000), asserted according to Franz (2005; the external third party).
- [James 17 Dec 2006] Here are three potential concepts: (a) Ranunculus abortivus L. sensu FNA sec. FNA (1997), (b) Ranunculus abortivus L. sensu Kartesz sec. Kartesz (2004) and (c) Ranunculus abortivus L. sensu FNA sec. Kartesz (2004). Kartesz (2004) asserts that potential concept (b) is congruent to potential concept (c) which is Kartesz(2004)'s interpretation of potential concept (a). It is unnecessary that potential concept (a) is (c). The relationship from (c) to (a) could be refers to, or, itegrated into (c) as the pointer to (a).
The TCS allows more choices if an expert simultaneously authors concepts AND asserts concept relationships. In that case, he or she has the option of placing the relationships inside the newly authored as OR outside in the . The former solution (1) should be used The latter solution (2) should be used if the author does not think of the relationship as an integral part of his or her new concept definition. Perhaps other data (diagnosis, included concepts, etc.) are sufficient to specify the present meaning. Or the relationship to earlier concepts is not so clear as to nail down the new definition exactly how the author wants it to be. Example: Equisetum hyemale L. subsp. affine (Engelmann) Calder & R.L. Taylor sec. Weakley (2005) “includes” E. hyemale var. affine (Engelmann) A.A. Eaton sec. Radford, Ahles & Bell (1968), as asserted by Weakley (2005). Here the latter author does not wish to define his new concept via its (inclusive) relationship to the 1968 concept. Rather, Weakley intends to provide readers with a "guide" to understanding the taxonomic legacy. The precise definition of his new concept lies in the diagnosis and explanatory comments.
No matter what option an author chooses at the time of authoring a concept, the possibility of authoring another (now by default) third-party relationship at a later time remains. Such a reassessment would "coexist" with the earlier relationship.
Version 1.01 of TCS has one enumerated list of RelationshipTypes? for both TaxonRelationships? and TaxonRelationshipAssertions?, however potentially one would not expect all of the relationships that can be specified when defining a TaxonConcept? to be sensible when asserting third party relationships - this requires some discussion.
In addition we need a wider discussion on the enumerated list of relationship types....
-- JessieKennedy - 13 Dec 2006
- [James 17 Dec 2006] Here are four potential cocnepts: (d) Brachycerinae sensu Kuschel sec. Kuschel (1995) , (e) Brachycerinae sensu Marvaldi & Morrone sec. Marvaldi & Morrone(2000), (f) Brachycerinae sensu Kuschel sec. Franz (2005) and (g) Brachycerinae sensu Marvaldi & Morrone sec. Franz (2005). Franz (2005) made an assertion that (f) includes (g). The relationship is a part of concepts in Franz (2005), and hence it is unnecessary to consider as the external third party's. Note that there is distinction between statement on (by Franz) and status of (can be modified by third parties) concepts behind this model (this is major distinction of Nomencurator from other potential taxon models). Status can be calcurated at database side, and can be given to the record created at database as an integration of potential concepts. This fact-based model does not require choice of author described below, and improves usability of TCS in poorly described taxa.