Name that goby

[doctormike]

Found on a reef in the Dry Tortugas at around 65 feet. Markings look like a masked goby or glass goby (very similar), but I'm hesitant to confirm this because the eyes are white, and every reference that I have shows these two fish with dark eyes.





Any thoughts?

Mike

 

[chillyinCanada]

Cool! You might have found something unique. As you said the coloring is right for masked or glass Moby, but eyes are not. Even the mask area between eyes and lip in your picture doesn't look quite right. On the other hand perhaps it isn't unusual to have white eyes with a black mask? OK further investigation leads me to believe that the eyes appearing white is not actually unusual but is only a matter of the white rectangles on the lateral line carrying on forward. Darn. For a moment thought you might have had something very special there.

 

[KeithG]

Could be a regional variation. Or maybe an immature specimen that just needs to age a bit to get the adult colors? I would go with either mask or glass. Take your pick.

Your picture does indicate the presence of darker area on each side of the eye, so it does not have totally white eyes. There is the faint appearance of a black bar through the eye. Maybe the exposure / head orientation has caused the black bar to appear washed out in the shot?

The various reference pictures I have seen have shown either a single white bar on top of a dark eye or a pair of white bars, one on top and one below a black eye.

 

[deborahdelamar]

Glass Goby, IMO. It has a dusky wedge on its nose vs. the larger "mask." Eye color is OK for glass goby.

 

[doctormike]

Thanks for the replies... good thoughts!

Humann and DeLoach say that they can't distinguish between Glass and Masked gobies from photographs, so they have a common entry for the two species...

I would think that embryologically the eyes develop separately from the rest of the body, so I don't know about a body marking just bleeding over onto the eyes, but I could be wrong.

M

 

[chillyinCanada]

Maybe the markings bleeding over into the eye "lids" or surrounding area has something to do with age/stage. I haven't been table to find anything that addresses this. As you did find, Humann/DeLoach has the two together, though with note that one more often hangout deeper than the other. At 65' more likely to be a glass than a masked.

 

[deborahdelamar]

Fish eyes are highly developed, complex structures and a specific fish's eyes may appear different when it is in different situations. I don't know how goby eyes work, but I know that your goby is a classic glass. The masked and glass are impossible to distinguish by human eye alone and, please understand that Paul and Ned wrote their field guides for divers who observe by eye. (Specifically to aid in the REEF Volunteer Surveyor program -- Paul founded REEF 20 years ago and has served as its president and fish ID instructor since then.) When we survey, these two are counted as one --"masked/glass." But there are ways to distinguish between the two when you have a macro photo -- without the need to count fin rays! Saludos!

Do you own the Reefnet DVD for the Caribbean? The sketches within are a highly recommended resource.

 

[chillyinCanada]

Deborah, very interesting thank you! You've stated emphatically that this is a classic glass but I wasn't able to discern upon which you have determined that. I'm viewing on a smartphone. Are you viewing on a larger screen and able to see finer detail and that is how you've spied a defining means of identification?

 

[deborahdelamar]

First, I forgot to address the white eye streaks that these gobies sometimes show. The white is on its body -- it is behind the eye but visible through the translucent part of the eye. The eye is translucent (reflected camera flash or light makes it appear white or off white) with a black pupil. Somehow, each of these two species can change its eyes to appear as two, large, protruding black saucers, which is really cool.

Re the ID: Call it a Masked/Glass and you can't go wrong!

 

[doctormike]

I don't know how goby eyes work, but I know that your goby is a classic glass.

Awesome, thanks so much! I always appreciate your expertise...



Mike

---------- Post added April 30th, 2013 at 04:00 PM ----------

Do you own the Reefnet DVD for the Caribbean? The sketches within are a highly recommended resource.

Would love to get it, but Windows only..!

Seriously, I hardly know anyone who uses a PC these days, really surprised that the Mac version is still "under development" - has been like that for a long time, from what I recall...

Mike