-oids and -ids

Fri, 16 Feb 1996 20:11:00 CDT

I've been peaking in on this discussion, but thought it had been explained
pretty well, so I kept my bioanthropological schnoz out of it; however, it seems
to be more and more confusing.

These terms are part of a suite of terms that are meant to designate a level of
generality or specificity in taxonomic grouping; or perhaps it will be better to
describe it as levels of inclusiveness. This system of terminology bears a
close resemblance to the system of classification of folk zoological terms
proposed by Berlin et al., but including many more intermediate steps.

Within any class of animals (and remember, class is a subdivision below the
phylum and kingdom), there are a number of families (and superfamilies). Much
like the nested figurines we see at the holidays, every level is a part of every
level above it and every level (down to the terminal name) is made up of many
more levels. So, the great fathers (sorry, but they *were* fathers) of
zoological nomenclature decreed that the suffix "-oid" (or "-oidea") should
properly designate a level of classification less inclusive than class and more
inclusive than families (which are designated by the suffix "id" or "idae").
Genera (the next less inclusive level) are generally designated with the "-ine"
or "inae" suffix; though sometimes these also apply to "tribes" (aka

So, for humans and other apes, the designations (and terminologies) should look
something like this.

CLASS: Mammalia
ORDER: Primates
Family: Hominidae Pongidae
Tribe: Homininae Ponginae
Genus: Homo Pan/Gorilla
Species: various various

NOTE: This is an approximation, and ALL groupings above species are flexible and
subject to much revision. For example, some would argue that Homo, Pan, and
Gorilla really ought to represent sister species within a single genus; or that
the separation between these lineages should at least be drawn at a much lower
(or more inclusive) level in our classification scheme. That is the stuff of
taxonomy and evolutionary biology -- heady stuff really, but beside the point of
how and why we give these critters the taxonomic names that we do.

Hope this helps.

Andrew Petto
Editor, National Center for Science Education
c/o Dept. of Anthropology, University of Wisconsin
1180 Observatory Drive, MADISON WI 53706-1393
ajpetto@macc.wisc.edu; 608/262-2866; (f) 5-2615
NSCE: ajp3265@madison.tec.wi.us; 608/259-2926; (f) 608/258-2415