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darter ID help
Started by
Guest_Uland_*
, Feb 06 2013 08:46 AM
18 replies to this topic
#1
Guest_Uland_*
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Posted 06 February 2013 - 08:46 AM
Antoine River Arkansas
#2
Guest_UncleWillie_*
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Posted 06 February 2013 - 10:47 AM
I am not familiar with Arkansas fish, but at first glance I would say bluntnose darter (E. chlorosoma).
Pretty similar to the johnny darter, but has that bulbous nose and that distinct spot at the caudal fin.
Pretty similar to the johnny darter, but has that bulbous nose and that distinct spot at the caudal fin.
Edited by UncleWillie, 06 February 2013 - 10:48 AM.
#3
Guest_Skipjack_*
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Posted 06 February 2013 - 11:35 AM
I bet Justin Baker would have some good input on this.
#4
Guest_blakemarkwell_*
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Posted 06 February 2013 - 08:09 PM
I wouldn't be comfortable calling any of those individuals E. nigrum.
#5
Guest_Casper_*
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Posted 06 February 2013 - 09:01 PM
Years ago i was visiting my Dad near Pine Bluff, Arkansas and i took a dipnet into an area in Bayou Barthalemu (SP?).
I caught a lot of fishes including some unique to me Starheads and little Shad that quickly died, but also what i think is the same darter as in your fine photographs.
When i got back to his house i compared the plastic bagged specimens to what i could find in Etnier's book and came up with the Bluntnose Darter, Etheostoma chloromum ( and in agreement to Uncle Willies post ). If you will check your TN book on page 479 you might agree as well. It is one of the few fish i have been able to ID on my own though i am still not 100% certain when i travel beyond my range. The X, Y and Ws on the side and the unique body shape led me to Et's description. Sure looks a lot like the Johnny Darters i see west of me and even kinda like Swamp and Cypress Darters. I reckon they are all kin. Check the TN book and see.
I caught a lot of fishes including some unique to me Starheads and little Shad that quickly died, but also what i think is the same darter as in your fine photographs.
When i got back to his house i compared the plastic bagged specimens to what i could find in Etnier's book and came up with the Bluntnose Darter, Etheostoma chloromum ( and in agreement to Uncle Willies post ). If you will check your TN book on page 479 you might agree as well. It is one of the few fish i have been able to ID on my own though i am still not 100% certain when i travel beyond my range. The X, Y and Ws on the side and the unique body shape led me to Et's description. Sure looks a lot like the Johnny Darters i see west of me and even kinda like Swamp and Cypress Darters. I reckon they are all kin. Check the TN book and see.
#6
Guest_Uland_*
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Posted 06 February 2013 - 11:23 PM
I wouldn't be comfortable calling any of those individuals E. nigrum.
My sentiments exactly but that is coming from the eyes of an Illinoisan.
Not being comfortable calling them E. nigrum is not the same as coming out and calling them E. chlorosoma
To add to this Blake...the E nigrum from the Spring River Arkansas did not look a whole like what I'm used to locally either.
I'm afraid I don't have frenum photos but as I recall the experience with the above fish, I was not impressed by a magnificently connected bridle.
#7
Guest_smbass_*
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Posted 07 February 2013 - 02:48 PM
Justin and I took a good look at these and came to the conclusion that they are E. nigrum because all of these fish appear to have a complete lateral line and E. chlorosoma has an incomplete lateral line. Uland maybe you can zoom in closer on the rear half of the fish on the oridinal images to see if you can indead see sensory pores of the lateral line the whole way back to the tail. If it is not there then I would change my answer to E. chlorosoma. The most difinitive character marking wise is the bar of pigment on the sides of the snout dipping down and conecting on the front of the nose forming a continuous line from one side to the other. I don't think that can be seen on these lateral veiw photos so it is difficult to use that charachter. Have any photos of these guys from head on, that would decide this for sure. I do think these seem more long and slender than nigrum here in Ohio but that could just be regional variance.
#8
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Posted 07 February 2013 - 07:56 PM
Brian, I really appreciate both you and Justin looking at these.
I quickly worked up a collage of the caudal in full size. Not terrific photos but hopefully enough to be helpful.
I quickly worked up a collage of the caudal in full size. Not terrific photos but hopefully enough to be helpful.
#9
Guest_smbass_*
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Posted 08 February 2013 - 10:40 AM
Ok I did a little more in depth study of these images... E. nigrum should have 8-10 spines in the first dorsal, 11-13 rays in the second dorsal, complete lateral line, and 42-50 scales in the lateral series. E. chlorosoma should have 9-10 spines, 10-11 rays, incomplete lateral line, and 50-60 scales in the lateral series.
After looking at the larger files for the rear of the fish they all appear to have some lateral pores further back than they should if they were E. chlorosoma but they get harder to see toward the rear of the fish. I can definitely see them where ever there is dark pigment though which makes me think they are probably there in the lighter areas and just not visible. So probably complete lateral line for all...
From top to bottom...
Fish one 9 spines, 11 rays, 53-54 scales (this part is tough but I think I'm pretty close)
Fish two 9, 11, 52-53
Fish three 9, 11, 50-52
Fish four 9, 12, 51-53
Fish five 9, 11, 52-53
Fish six 8, 11-12 (may be a very small one at the rear of the fin), 50-52
So there is one spine count and one maybe two ray counts that favor E. nigrum, but all scales counts favor E. chlorosoma, and the lateral lines favor E. nigrum. To add to this Justin says the E. nigrum in this area are different genetically than E. nigrum else where so maybe they are different morphologically too. If it wasn't for the scale counts seeming to be high I would call them E. nigrum but those make me not very confident. Guess you have to go back and take pictures of their faces... These fish certainly look more long and slender than E. nigrum found here in Ohio.
After looking at the larger files for the rear of the fish they all appear to have some lateral pores further back than they should if they were E. chlorosoma but they get harder to see toward the rear of the fish. I can definitely see them where ever there is dark pigment though which makes me think they are probably there in the lighter areas and just not visible. So probably complete lateral line for all...
From top to bottom...
Fish one 9 spines, 11 rays, 53-54 scales (this part is tough but I think I'm pretty close)
Fish two 9, 11, 52-53
Fish three 9, 11, 50-52
Fish four 9, 12, 51-53
Fish five 9, 11, 52-53
Fish six 8, 11-12 (may be a very small one at the rear of the fin), 50-52
So there is one spine count and one maybe two ray counts that favor E. nigrum, but all scales counts favor E. chlorosoma, and the lateral lines favor E. nigrum. To add to this Justin says the E. nigrum in this area are different genetically than E. nigrum else where so maybe they are different morphologically too. If it wasn't for the scale counts seeming to be high I would call them E. nigrum but those make me not very confident. Guess you have to go back and take pictures of their faces... These fish certainly look more long and slender than E. nigrum found here in Ohio.
#10
Guest_Uland_*
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Posted 08 February 2013 - 12:17 PM
Brian,
I can't thank you enough for your time in looking at these.
I don't want to seem lazy but rather I want to learn from those with more experience, what really matters when distinguishing E. nigrum/chlorosoma.
I must ask a stupid question though.....where must the LL pores terminate to be considered a complete lateral line? Where scales become irregular at the base of the caudal fin?
Admittedly, the pores terminate about the same place on these fish as local E. nigrum but that ain't sayin' much.
and one last thought....could the bridle alone sway you either way on this fish?
I can't thank you enough for your time in looking at these.
I don't want to seem lazy but rather I want to learn from those with more experience, what really matters when distinguishing E. nigrum/chlorosoma.
I must ask a stupid question though.....where must the LL pores terminate to be considered a complete lateral line? Where scales become irregular at the base of the caudal fin?
Admittedly, the pores terminate about the same place on these fish as local E. nigrum but that ain't sayin' much.
and one last thought....could the bridle alone sway you either way on this fish?
#11
Guest_IsaacSzabo_*
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Posted 08 February 2013 - 12:38 PM
According to Fishes of Arkansas, E. chlorosomum differs from E. nigrum "in having dark stripe extending forward from each eye continuous around snout above upper lip; lateral line incomplete, usually extending only to below soft dorsal fin; and scaled cheeks."
E. nigrum differs from E. chlorosomum "in not having preorbital dark bars continuous around the snout, in usually having naked cheeks, and in having complete lateral line."
To me it looks like the lateral line extends beyond the soft dorsal in all of these, indicating E. nigrum. It is difficult to determine the nature of the preorbital bar without a view from the front. I wonder if it is possible to detect the presence/absence of cheek scales in the high resolution photos?
E. nigrum differs from E. chlorosomum "in not having preorbital dark bars continuous around the snout, in usually having naked cheeks, and in having complete lateral line."
To me it looks like the lateral line extends beyond the soft dorsal in all of these, indicating E. nigrum. It is difficult to determine the nature of the preorbital bar without a view from the front. I wonder if it is possible to detect the presence/absence of cheek scales in the high resolution photos?
#12
Guest_smbass_*
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Posted 08 February 2013 - 01:20 PM
I must ask a stupid question though.....where must the LL pores terminate to be considered a complete lateral line? Where scales become irregular at the base of the caudal fin?
Yes
I am not 100% sure they make it this far back on these fish but they certainly appear to go beyond the rear of the soft dorsal where it should stop for E. chlorosomum. Also because this seems unclear to me I think I would be swaied toward E. chlorosomum if there was a complete bridle around the tip of the snout considering there is some potential overlap in all the other characters. I looked at a few of our museum specimens from southern populations of E. nigrum and some have rather well developed bars that go forward from the eye and down onto the lip but the two sides do not connect across the tip of the snout. Also looking at several E. chlorosomum specimens (we even had one from AR) they all obviously have the pigment connect across the tip of the snout. Since the lateral line character seems to contradict the scale counts and the spine and ray counts are rather neutral I am pretty undecided on these. I would want to examine these along with known voucher specimens of both species from AR to make a call. It would be nice to have someone chime in who is more familiar with E. chlorosomum because I have never seen live ones in person. Didn't Konrad Schmidt present something about finding them in MN at the convention last year?
#13
Guest_smilingfrog_*
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Posted 08 February 2013 - 02:15 PM
Didn't Konrad Schmidt present something about finding them in MN at the convention last year?
He has an article about that in American Currents volume 37, the one with the Elassoma gilberti on the cover. He has contact info in there too.
Edited by smilingfrog, 08 February 2013 - 02:16 PM.
#14
Guest_smbass_*
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Posted 08 February 2013 - 02:33 PM
I have his contact info just not sure if he ever gets on here, I'll send him an e-mail.
#15
Guest_Skipjack_*
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Posted 09 February 2013 - 07:41 AM
Are the orange knobs on the pectorals a defining character? Have never noticed this in my local nigrum.
#16
Guest_Uland_*
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Posted 09 February 2013 - 02:44 PM
Are the orange knobs on the pectorals a defining character? Have never noticed this in my local nigrum.
Matt, I do feel the pectoral "knobs" are worthy of discussion but I'd not heard of this before so thought it of little value concerning the identity of these fish.
below is a photo of the "knobs" on fish #702
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#17
Guest_smbass_*
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Posted 14 February 2013 - 03:59 PM
A couple of comments from guys who have handled both species, looks like these are E. nigrum. I was leaning toward that but nice to have these guys chime in, both looked at the photos...
Guys,
Thanks for sending the images.
These are Johnny Darters. You have to be careful using meristic counts with E. nigrum because the species across its range is so variable (this is why we have numerous subspecies such as eulepis, nigrum, and susanae). Some subspecies have naked breasts, the dorsal fin counts and anal fin spines are quite variable, etc. E. chlorosoma has a very elongate caudal peduncle, more so than what I see on these specimens. Also, E. nigrum has rather tell-tale “W’s” and “X’s” more-or-less centered on the sides of the body and these markings are quite vivid, while E. chlorosoma has smaller W’s and X’s that are somewhat clustered, sometimes forming reticulated lines and they are not as bold as those on E. nigrum. Of course to be 100% positive for anyone has not collected both species, you have to observe the preorbital bar, which is continuous.
Bob Hrabik
To me, the markings and texture of the scales (coarse) indicate Johnny. I searched for them many years meticulously checking the keying characteristics of the two species, but when I did get my first one, I discovered the similarities aren't even close.
Konrad Schmidt
Guys,
Thanks for sending the images.
These are Johnny Darters. You have to be careful using meristic counts with E. nigrum because the species across its range is so variable (this is why we have numerous subspecies such as eulepis, nigrum, and susanae). Some subspecies have naked breasts, the dorsal fin counts and anal fin spines are quite variable, etc. E. chlorosoma has a very elongate caudal peduncle, more so than what I see on these specimens. Also, E. nigrum has rather tell-tale “W’s” and “X’s” more-or-less centered on the sides of the body and these markings are quite vivid, while E. chlorosoma has smaller W’s and X’s that are somewhat clustered, sometimes forming reticulated lines and they are not as bold as those on E. nigrum. Of course to be 100% positive for anyone has not collected both species, you have to observe the preorbital bar, which is continuous.
Bob Hrabik
To me, the markings and texture of the scales (coarse) indicate Johnny. I searched for them many years meticulously checking the keying characteristics of the two species, but when I did get my first one, I discovered the similarities aren't even close.
Konrad Schmidt
#18
Guest_smbass_*
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Posted 15 February 2013 - 09:20 AM
Bob wanted to add this to the end of his coment.... which is continuous for E. chlorosoma.
#19
Guest_Uland_*
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Posted 18 February 2013 - 07:05 PM
Once again I am most appreciative of the help in this topic. I feel as though I have learned quite a bit and still on the hunt to see my first E. chlorosoma.
Once I do capture specimens, I will offer up comparative photos.
Once I do capture specimens, I will offer up comparative photos.
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