[Taxacom] Quick question regarding formation of some family names in botany

[Tony Rees]

Dear Taxacomers,

I have come across the following issue and believe the answer lies in the
relevant nomenclatural Code (ICNafp), but need some expert guidance since
my latin is not so good...

The question concerns the correct formation of family names (and above)
based on genus names ending in -physis (examples in dinoflagellates,
treated under the botanical Code for this purpose: Oxyphysis, Dinophysis)
for which both types of derived family names have been used in the
literature, without or with the final "i", namely  Oxyphysaceae /
Oxyphysiaceae,  Dinophysaceae / Dinophysaceae. The same applies to names of
higher rank based on such genera, e.g. Dinophysales / Dinophysiales, etc.

The relevant Article of the current ICNafp states:

"*18.1.* The name of a family is a plural adjective used as a noun; it is
formed from the genitive singular of a name of an included genus by
replacing the genitive singular inflection (Latin *‑**ae,* *‑**i,* *‑**us,*
*‑**is;* transcribed Greek *‑**ou, **‑**os,* *‑**es,* *‑**as,* or *‑**ous,* and
its equivalent *‑**eos*) with the termination *‑**aceae* (but see Art. 18.5
<https://www.iapt-taxon.org/nomen/pages/main/art_18.html#Art18.5>). For
generic names of non-classical origin, when analogy with classical names is
insufficient to determine the genitive singular, *‑**aceae* is added to the
full word. Likewise, when formation from the genitive singular of a generic
name results in a homonym, *‑**aceae* may be added to the nominative
singular. For generic names with alternative genitives the one implicitly
used by the original author must be maintained, except that the genitive of
names ending in *‑**opsis* is always *‑**opsidis*."

So I get the feeling that versions without the included "i" would be
correct in this instance (Oxyphysaceae, Dinophysaceae) but would welcome
confirmation from others who are more expert in this area than I.

Regards - Tony
Tony Rees, New South Wales, Australia
https://about.me/TonyRees
www.irmng.org