PROPOSAL NO.: 2001-01

DATE: December 15, 2000

NAME: Designating Taxonomic Hierarchies in Field 754 (Added Entry--Taxonomic Identification) in the Bibliographic format

SOURCE: Florida Center for Library Automation

SUMMARY: This paper proposes adding subfields $c and $z to field 754 to designate the taxonomic hierarchy of the data in subfield $a and to provide a public note. Likewise, the redefinition of subfield $a is proposed to contain the taxonomic name only.

KEYWORDS: Field 754; Subfield $a, in field 754; Subfield $c, in field 754; Subfield $z, in field 754, Taxonomic identification; Added Entry--Taxonomic Identification

RELATED: 2000-08 (May 2000)


12/15/00 - Forwarded to the MARC Advisory Committee for discussion at the January 2001 MARBI meetings.

01/13/01 - Results of the MARC Advisory Committee discussion - Approved as amended.

The following subfields were added:

02/01/01 - Results of LC/NLC review - Agreed with the MARBI decisions.

PROPOSAL NO. 2001-01: Designating Taxonomic Hierarchies in Field 754


Field 754 (Added entry–Taxonomic Identification) contains taxonomic identification information associated with the item described in the record. It has only two subfields defined apart from standard $6 and $8 subfields. Subfield $a is defined as "taxonomic name/taxonomic hierarchical category" and $2 is for the "source of taxonomic identification". MARC 21 explains that "subfield $a contains a taxonomic name and the taxonomic hierarchical category to which the name belongs. The taxonomic name conforms to the syntax controls of the taxonomic classification system identified in subfield $2. Subfield $a is repeatable for each taxonomic name/taxonomic hierarchy associated with the item. Each combination is input in repeatable $a subfields in taxonomic hierarchial order." The example given is:

754 ## $aPlantae (Kingdom) $aSpermatophyta (Phylum) $aAngiospermae (Class) $aDicotyledoneae (Subclass) $aRosales (Order) $aRosaceae (Family) $aRosa (Genus) $asetigera (Species) $atomentosa (Variety). $2[code for Lyman David Benson's Plant Classification]

Proposal No. 2000-08 (Definition of Additional Subfields in field 754 (Added Entry–Taxonomic Identification) in the MARC 21 Bibliographic Format) was presented to the MARC Advisory Committee in July 2000. It proposed adding subfields $b through $m in field 754 to provide different levels of hierarchy to record taxonomic identification rather than repeat subfield $a. Each subfield was designated as to its hierarchical level. Discussion suggested that the structure of field 654 (Subject Added Entry–Faceted Topical Terms) be considered for coding the data because it is more expandable. This solution would involve using a new subfield to identify the facet or hierarchical designation in the subfield that follows it.


Field 754 is used by the State University System of Florida for taxonomic information in Florida Environments Online, a database of resources pertaining to the species and ecology of Florida. Florida also advocates the use of 754 within the Z39.50 Biological Interest Group (Z-Big) when mapping their biological attribute set, commonly known as the "Darwin Core," to MARC.

A problem with field 754 as currently defined is that labels are embedded within data fields, causing a lack of flexibility on display. Whereas some implementations may wish to display complete taxonomic hierarchy with embedded labels such as:

(Kingdom) Plantae -- (Phylum) Spermatophyta -- (Class) Angiospermae -- ...

others, particularly within scientific applications, may want to compress this:

Plantae -- Spermatophyta -- Angiospermae ...

Current input conventions would probably result in the following display:

Plantae (Kingdom) -- Spermatophyta (Phylum)-- Angiospermae (Class)-- ...

Genus and species, for example, are very commonly used together for searching, and in some applications may be the only taxonomic information recorded. Institutions will want the flexibility to display and search data so that a search on "Rosa setigera" could return data in the form of "Rosa setigera" rather than "(Genus) Rosa (Species) setigera." While the desired display is possible, it requires parsing textual information to strip parenthetical data held within it.

It is proposed that the definition and use of field 754 be changed to be more parallel to field 654 (Subject Added Entry–Faceted Topical Terms) to allow for separating the taxonomic category from the taxonomic name. In field 654, subfield $c is used to designate the facet or hierarchy of the thesaurus terms in subfields $a and $b, e.g.:

654 1#$ck $ainterior design. $2aat

It is proposed that subfield $a in field 754 be redefined to contain the taxonomic term only, and a new subfield $c be defined to designate the taxonomical hierarchy being designated. Subfield $c is repeated preceding each subfield $a to which it relates, as is recorded in field 654. Example:

754 ##$cgenus $aRosa $cspecies $asteigera

This would allow more flexible display, as it is easier to add a constant label than to strip embedded data. The terms used in subfield $c would be those used in the source identified in $2.

Subfield $z (Public note) is also needed in the field for the common name corresponding to the scientific name given in other subfields. Common names equate to genus-species, so it would not be necessary to repeat the subfield after each appropriate $a. Searching would probably be desirable on common names in $z. Example:

754 $cfamily $aGekkonidae $cgenus $aHemidactylus $cspecies $aturcicus $zCommon names: Mediterranean gecko, Mediterranean gekko.


In field 754 (Added entry--Taxonomic identification) of the MARC 21 bibliographic format:

Go to:

Library of Congress Library of Congress
Library of Congress Help Desk (02/01/01)