[Taxacom] Quick question re formation of a family-group name

Doug Yanega dyanega at ucr.edu
Mon Dec 20 17:48:53 CST 2010

Tony Rees wrote:

>For a genus of flatworms (Pericelis Laidlaw, 1902) which is the type 
>genus of a family, the family name is given variously as Pericelidae 
>(e.g. in Parker, 1982 and in the World Register of Marine Species 
>and ITIS) or Pericelididae (as given in other sources e.g. the 
>Turbellarian taxonomic database at this time).
>The Zoological Code allows either construction so far as I can tell, 
>and ultimately goes to "prevailing usage":
> If the stem so formed ends in -id, those letters may be 
>elided before adding the family-group suffixes. If, however, the 
>unelided form is in prevailing usage, that spelling is to be 
>maintained, whether or not it is the original spelling.
>Example. The family-group names HALIOTIDAE and HALIOTOIDEA are not 
>changed to HALIOTIDIDAE and HALIOTIDOIDEA, even though the stem of 
>Haliotis is Haliotid-, as the latter spellings are not in prevailing 
>"elided" was not a term I was previously familiar with, but means 
>omitted or eliminated for present purposes.
>If that well known authority Google is anything to go by, 
>Pericelidae wins over its longer rival (11,700 vs. 143) but I have a 
>feeling that this may conceivably be skewed by propagation and 
>re-propagation of some high profile listing, e.g. Catalogue of Life 
>- for example unreviewed names from the original NODC taxonomic code 
>are still present in ITIS and in some cases passed up to CoL without 
>further comment or scrutiny, and this appears to be one such name. 
>(This is not intended to be a springboard for criticism of that 
>system, just a possible indication of how and why such things may 
>Suggestions, authoritative or not would be welcome as to which name 
>would be more appropriate to follow at this time - at present my 
>preference would be for the longer form since that appears to be 
>used in arguably more authoritative sources, but I am open to other 
>evidence. For example in Zoological Record, a search on 
>"Pericelidae" yields one hit only, but Pericelididae yields none... 
>Pericelidae has 13 hits on Google scholar, Pericelididae has 3.
>Does anyone have a magic bullet here, maybe?

If there are two spellings in use, then one has to appear at an 
earlier date in the literature. The *default* option under the Code 
is to use the oldest name, but there are conditions - such as 
prevailing usage - where the default does not apply. The Code is 
reasonably clear on what sorts of sources qualify for determining 
"prevailing usage", so - in principle - a thorough look at the 
primary literature dating back 50 years (e.g., see Art. 23.9.1) 
*should* be sufficient. It is always possible in a very small group 
with few publishing authors, that these minimum requirements are not 
met, and various situations and approaches are outlined in other 
parts of Article 23.9, some of which may require petitioning the ICZN 
for a ruling.

In the present case, the names are rather close to the insect family 
Periscelididae, and the shorter spelling is less likely to be 
confused, but that's not *technically* a homonym, so it doesn't 
really come into play.

It seems possible that someone not conversant with the Code but 
conversant in Latin is responsible for the change from Pericelidae to 
Pericelididae, but the citation you give - - is quite 
explicit that the name should NOT be changed, even if it's bad Latin. 
Bad Latin is not a Code violation, though many people seem to act as 
if it is.


Doug Yanega        Dept. of Entomology         Entomology Research Museum
Univ. of California, Riverside, CA 92521-0314        skype: dyanega
phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82

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