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The real genus problem
But seriously, the problem of the genus is a serious one that is receiving
hardly any examination in the technical literature. Just saying that we
should settle on traditional assignments and not worry too much about it is
dubious because the genus continues to be used as a means of comparing
diversity
over place and time in technical papers examining evolutionary, extinction,
paleogeographic and other items, as well as between groups of organisms.
Such comparisons reflect reality only if genera provide a reasonably
consistent measure of gradistic diversity. At this time they do not. The dozens
of
species highly diverse recent and extant Varanidae consists of one genus
(Megalania recently being formerly and properly sunk into Varanus since it was
nothing more than an oversized goanna and nothing makes it particularly
special vis-à-vis the other varanid species whose size range is enormous
regardless). The genus is under active research (genetics indicates the old
subgenera
are probably bogus) and there is no attempt to split it. Canis has a lot of
species with substantial anatomical divergence, as do Panthera and Felis.
There is tremendous variation within Homo. On the other hand Saurornithoides
mongoliensis and junior were just generically split even though they show
much less variation than is present in Canis or Varanus. The highly uniform
hypacrosaur lambeosaurines are split into a number of genera even thought he
morphological variation is largely limited to cranial features characteristic
of species identifiers. Same for centrosaurines and chasmosaurs.
Something has to be done about the situation. Seriously, the current
sloppiness is scientifically dysfunctional and embarrassing. Either stop using
genera to measure diversity although it is not clear what the alternative is
(this can include making genera monospecific although that seems unlikely and
may not be practical), or make genera more uniform as I am trying to do by
lumping some overly relatively split genera and splitting up the fewer number
that are overlumped (as per Iguanodon), although this too involves
practical problems.
GSPaul
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