Good to hear from you.
>What morphological and meristical difference between them?
I'm currently away from my notes, but off the top of my head pullum has
smaller scales (R.D. Ross noticed this back in the early 1960s and mapped
fine-scale distribution of the two in NY and PA), michauxi has a different
tuberculation pattern and pharyngeal tooth formula (usually), and plumbeum
has bright red-orange fins. It ain't rocket science. Analyses of some of the
others are still in the works.
>BTW wondering what is the most numerous cyprinid in NA?
Tough question... to my knowledge, no one has attempted a quantitative
ranking of fish abundance across the US.
The Maryland Biological Stream Survey performed a quantitative study of 955
randomly selected Maryland streams between 1995-1997. This study identified
blacknose dace as the most abundant cyprinid (n=64631), followed by creek
chub (n=19685), rosyside dace (n=17205), longnose dace (n=15549), bluntnose
minnow (n=12920), and central stoneroller (n=12069). This is probably
consistent with other areas of the mid-Atlantic region. It is interesting to
note that numerically dominant taxa primarily occupy 1st and 2nd order
headwater streams. While it is dangerous and difficult to extrapolate from
this data set to the entirety of North America, one could make a case that
given the widespread nature of creek chubs and the numerical dominance of
headwater habitats, they might beat out other minnows that are more abundant
in larger stream channels. That said, it's a wild guess - and given the
sheer abundance of stonerollers in the central US, who knows.
cheers,
Dave
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