Evolutionary history of the centrarchids
#2 Guest_rjmtx_*
Posted 31 December 2008 - 11:46 AM
#3 Guest_Moontanman_*
Posted 31 December 2008 - 12:49 PM
Check out this link to the Mayden lab at St. Louis University. http://bio.slu.edu/m...fish/index.html
I checked that out, I was hoping dwarf and pygmy sunfishes would be included.
#4 Guest_ashtonmj_*
Posted 31 December 2008 - 01:38 PM
#6 Guest_Elassoman_*
Posted 20 January 2009 - 10:01 PM
The Harris lab (which I work for) and the Mayden lab have traditionally focused on the phylogenies of Micropterus and Lepomis. This is probably due in a large part to the broad interest these species enjoy as sportfish. Their collaborative group has put out a brand new paper on Ambloplites relationships (Roe et al. 2008). The Near lab at Yale also works on the evolutionary history of centrarchids, and, to the best of my knowledge, has the only multi-gene data set at present.
Regarding the Enneacanthus dwarf sunfishes, everyone agrees that they are sunfishes. As you might guess by looking at them, E. gloriosus and E. obesus are each other's closest relative. E. chaetodon is a bit more genetically distinct, and probably is more similar to the group's ancestor. The genus Enneacanthus is related to the Flier (Centrarchus), Rock Basses (Ambloplites), Sacramento Perch (Archoplites) and the Crappies (Pomoxis), but there is still some work to be done to determine exactly how these branches are aranged on the tree. This all makes sense when you consider the ecology and behavior of these species. Unlike Lepomis and Micropterus, none of these species are super territorial, they are generally more likely to inhabit slow moving habitats, and they have a slow stalking way of catching their prey. In aquaria, it is really difficult to get any of these fish to take food that isn't wriggling. In contrast, I have three Lepomis species in my tank that eat pellets from my fingers.
Regarding "the Elassoma problem", there are nearly as many ideas about the origins of pygmy sunfishes as there are fish in the sea...literally. There are some very strong opinions about this question, only some of which are supported by good data. Mettee and Scharpf gave a good summary of the historical hypotheses, which is posted here. Recently, various genetic analyses have placed the pygmy sunfishes on the same branch as spiny eels and swamp eels, wrasses, boarfish, scorpionfishes, seahorses and other groups. None of these relationships would be predicted from what we know of their morphology. To say the least, right now no one can be absolutely sure where they fit. As part of my dissertation, I am specifically looking at the placement of Elassomatidae. I'm not claiming that I'll figure it all out within the next two years, but I hope to rule out some of the groups that have been proposed out of tradition etc. I'll keep you posted on what I find.
Mike Sandel
Edited by Elassoman, 20 January 2009 - 10:06 PM.
#7 Guest_Newt_*
Posted 20 January 2009 - 10:59 PM
A zonatum-type specimen collected in
a Rotenone survey in Tennessee may represent a new, undescribed species.
Has any more research been done with this population? And what part of TN is it in? No need for specifics, I'm not looking to collect them, I'm just interested in the biogeography.
#10 Guest_centrarchid_*
Posted 21 January 2009 - 11:20 AM
Recently, various genetic analyses have placed the pygmy sunfishes on the same branch as spiny eels and swamp eels, wrasses, boarfish, scorpionfishes, seahorses and other groups. None of these relationships would be predicted from what we know of their morphology.
They do look a lot like sticklebacks in terms of how they swim and head design which to me are like bird wings and flight style, hard to change as intermediate designs may require special circumstances to be optimal. The breeding habits of the pygmies are not all that different from what you would expect of a stickleback ancester prior to developement of their nest building habits. Do male pygmies produce any excretions associated with reproduction (i.e. scent marking of breeding cite)?
#11 Guest_Moontanman_*
Posted 21 January 2009 - 04:31 PM
Hey Moon,
The Harris lab (which I work for) and the Mayden lab have traditionally focused on the phylogenies of Micropterus and Lepomis. This is probably due in a large part to the broad interest these species enjoy as sportfish. Their collaborative group has put out a brand new paper on Ambloplites relationships (Roe et al. 2008). The Near lab at Yale also works on the evolutionary history of centrarchids, and, to the best of my knowledge, has the only multi-gene data set at present.
Regarding the Enneacanthus dwarf sunfishes, everyone agrees that they are sunfishes. As you might guess by looking at them, E. gloriosus and E. obesus are each other's closest relative. E. chaetodon is a bit more genetically distinct, and probably is more similar to the group's ancestor. The genus Enneacanthus is related to the Flier (Centrarchus), Rock Basses (Ambloplites), Sacramento Perch (Archoplites) and the Crappies (Pomoxis), but there is still some work to be done to determine exactly how these branches are aranged on the tree. This all makes sense when you consider the ecology and behavior of these species. Unlike Lepomis and Micropterus, none of these species are super territorial, they are generally more likely to inhabit slow moving habitats, and they have a slow stalking way of catching their prey. In aquaria, it is really difficult to get any of these fish to take food that isn't wriggling. In contrast, I have three Lepomis species in my tank that eat pellets from my fingers.
Regarding "the Elassoma problem", there are nearly as many ideas about the origins of pygmy sunfishes as there are fish in the sea...literally. There are some very strong opinions about this question, only some of which are supported by good data. Mettee and Scharpf gave a good summary of the historical hypotheses, which is posted here. Recently, various genetic analyses have placed the pygmy sunfishes on the same branch as spiny eels and swamp eels, wrasses, boarfish, scorpionfishes, seahorses and other groups. None of these relationships would be predicted from what we know of their morphology. To say the least, right now no one can be absolutely sure where they fit. As part of my dissertation, I am specifically looking at the placement of Elassomatidae. I'm not claiming that I'll figure it all out within the next two years, but I hope to rule out some of the groups that have been proposed out of tradition etc. I'll keep you posted on what I find.
Mike Sandel
Yes , please keep us informed of your progress. I appreceate the info.
#12 Guest_Elassoman_*
Posted 14 February 2009 - 04:58 PM
The "zonatum like" specimen was collected, and is possessed by Dr. Wayne Stearns at the NC museum. He and Dr. Etnier (I think) collected in it southEAST Tennessee. This is not within the range of E. zonatum, and quite far northeast of the E. alabamae. It is a small stream surrounded by uplifted foothills; not what you think of as typical Elassoma habitat. They have been back to the area a number of times, and never collected another specimen. The weird thing is, he didn't know he had the fish until he saw it in a jar of formalin in the lab. This means that it could have been mixed in from a different jar accidentally. Otherwise, perhaps they just haven't found the "source" of the population, and this was just a wandering soul that they encountered in the stream. Then there is always the "bird feet" hypothesis...Someday I am going to go take a look at the preserved fish.
Somewhat related; there is a single record of Elassoma zonatum far up the Colorado River in Texas. The other fish in the jar are Cyprinella lutrensis. Picture a very dry, sandy landscape with little chance of a pygmy sunfish making a living. The curator of this collection is quite sure this specimen was mixed up during sorting, and came from somewhere else, but it's hard to be absolutely sure...
#13 Guest_Newt_*
Posted 14 February 2009 - 06:08 PM
#16 Guest_Elassoman_*
Posted 11 May 2009 - 03:07 PM
Attached Files
Edited by Elassoman, 11 May 2009 - 03:08 PM.
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