Article © Julian Dignall, uploaded December 01, 2000.
Editor's Note. This species is was described in 2011 as Baryancistrus xanthellus. While the l-number discussion below is more or less obsolete, I've left it unaltered as it was written some eleven years before the description and still holds up quite well! It is also both interesting and useful to see where we've come over the years too.
X marks the spot where collectors struck gold! The problem, if you could call it that, with the maps below is that there is more than one "X". There are in fact 3, this is because there are at least three gold nugget plecos. Oh, and they have 4 "L" numbers among them too.
|X = L81, X = L177 and X = L18 & L85|
Although X marks the spot each one is between 80 and 100 miles away from its nearest neighbour. Perhaps "X" is for the Rio Xingu rather than precise locations! Anyway, L18, L81, L85 and L177 are all gold nugget plecos. The table below will hopefully help with identification. What you have to bear in mind is that the comparisons are only really useful when comparing similarly sized fish and that individuals patterning is very variable anyway. Aqualog's original Loricariidae - All "L" numbers actually has a good trio of pictures showing juvenile, sub-adult and adult of L18/L81. Look up L85 for these pictures. It should be noted that the pictures in Aqualog for all these L-numbers are accurate and good representations of the original fish. Alright so far, but what are the factors that differentiate these fish? The following table should help.
|L018||This is the "common" gold nugget with medium sized spots. This is a picture of a juvenile. L018 is found in area around Altamira on the Rio Xingu. This is about 75 miles downstream (North) of where the Rio Iriri joins the Rio Xingu.|
|L081||This is the small spot gold nugget from the lower Rio Xingu. The yellow colouration on this fish (spots and fin seams) tends to be paler. This is a picture of a young sub-adult.|
|L085||These are adult L18, they are one and the same fish. The adult colouration is markedly different however. This is a picture of an adult male.|
|L177||This is the big spot gold nugget from the Rio Iriri tributary. The yellow colouration on this fish (spots and fin seams) tends to be a stronger yellow. This is a picture of a juvenile. Arguably the most cosmetically pleasing of the gold nugget tribe.|
This all seems relatively straightforward, Corydoras keepers have been doing this sort of thing for years, right? Well, not exactly. The individual fish can also change colour - exactly the same fish as pictured on a dark piece of wood against a light background will look very different seconds later because it is now sitting on lighter gravel out in the open. With identification being such a fraught, tentative process, it is perhaps reassuring to know that care of all of these fish is somewhat simpler if not less demanding.
Copyright information for the images used in this article can be found on the species' full Cat-eLog page.
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