Science and Hobby making history (again): my field notes on the legendary
Zebra Corydoras? expedition.

Luiz Fernando Caserta Tencatt

First of all, in the names of Marcelo Britto, Willian Ohara and my own of course, I want thank all hobby people for the partnership, empathy and generosity. You all made it possible. Thank you!

Marcelo Britto is one of the curators at the Museu Nacional (Rio de Janeiro), Willian Ohara is a professor at the Universidade Federal de Rondia (Ji-Paran and I am a temporary professor at the Universidade Estadual de Mato Grosso do Sul (Coxim). In a few words, we were, respectively, about 3000, 1700 and 1500 kilometers away from our last destination in Par For now, we will save the exact localities for safety purposes (you all know the poaching problems regarding CW111 and others). Our meeting point was in Mato Grosso, at the city of Sinop. Marcelo and Willian were able to go there by airplane, however, in order to save some money, I did a quite boring but relatively comfortable 16 hours trip.

Our official vehicle was waiting for us in Sinop, a pretty good pickup truck to face the mighty Amazon. Marcelo and Willian arrived there first, in July 5th, and I arrived in July 6th. There, they payed a visit to a colleague, professor and also ichthyologist (ecology) Luc ia Carvalho, at the Universidade Federal de Mato Grosso. She is keeping a small but good fish collection there, specially Xingu River species (which revealed a new Corydoras ahaha! A future RAP Project). They were obviously crazy to catch fish and since I would only be there on the next day, they did a small warm up collecting trip in a tributary to the Xingu River basin close to Sinop. They captured some nice stuff, however, not even a single Corydoras (though Lucélia said C. apiaka is pretty common by there). Megalechis was the only Callichthyidae that my friends captured there, by the way. They also captured at least two species of Hypoptopomatinae (the members of this group were observed and captured in most of our collecting sites). I will not waste your time with the scaly fish captured there, all boring as usual (lol just kidding).

So, in the July 6th we started to drive to our first collecting point at about 5:00 pm. On our way, we stopped at a very beautiful place, full of rapids and an awesome waterfall in the Curuá River. We took nice pictures and it was possible to observe some Harttia specimens laying on the rocky substrate. Simply beautiful! After some hours on the road, we arrived in the first checkpoint (July 7th). Not long ago, Willian Ohara captured some of the few specimens in museums of Corydoras sp. bonita (bonita = beautiful), as they were identified during its first discovery at the Pipe Expedition (see http://silurus.acnatsci.org/ACSI/field/Pipe_Expedition/Callichthyidae.html), and which we are considering to be CW111. He provided three collecting sites were these few known preserved specimens were captured. And so we headed there. The first site was relatively close to our checkpoint. We started to catch fish at the morning of the July 7th. My loyal cast net was obviously there and it was eager for action (lol), I am proud to say that my first throw was beautiful, a single but nice specimen of a new Ancistrus (Ancistrus sp. sutura, see http://silurus.acnatsci.org/ACSI/field/Pipe_Expedition/Loricariidae.html), which is being described by my friend Emanuel Neuhaus and Marcelo Britto, his advisor. Also, a good number of Harttia cf. dissidens (this is possibly one of the most common catfish species there) and piabas/lambaris (Astyanax, Bryconops, Jupiaba, Moenkhausia...). Ohara captured some specimens of a very interesting but tiny fish, Paracanthopoma sp. Hours and hours, with all possible fishing methods (cast net, seine net, sieve...) and not even a single Corydoras. We were starting to get a little bit worried...really.

The sun was going down when we decided to go back and think of a new plan, Ohara quickly passed his sieve on the sandy bottom...he laughed and said guys, I said they were here, showing a 15 mm total length (TL) baby Cory (LOL). If we have babies, moms and dads must be here somewhere, we started to think on it as a mantra. It is well known that it is easier to catch Corydoras at night, though they are diurnal. They like to take some rest at the sandy banks ("beaches") at night. When the night fell, we picked our flashlights and our fishing equipments. In a few minutes we saw some large Corydoras (happiness my friends...that small, quick but very good moment when you know that the name of the feeling is happiness). It took a little time for us to realize that our current equipment was not good to catch them. Yes, frustrating. However, we were using those very small aquarium sieves to select the fishes for preservation in alcohol or formalin. Eureka! All that "fancy" equipment and what saved us was the good old small "aquarium sieves". We aimed them with the flashlight and grabbed them one-by-one (ONE-BY-ONE). The first one though was not the Corydoras sp. bonita but the "Corydoras sp. clara" (see http://silurus.acnatsci.org/ACSI/field/Pipe_Expedition/Callichthyidae.html).

This species is obviously new, and seems to be close related to the species within what I am calling of the Corydoras trilineatus group or simply the super Corydoras groups. A new species is always welcome! Suddenly, another species popped up. However, the best match was not exactly CW111 but CW146. So, for us, we spent this whole night capturing Corydoras sp. clara and CW146. We captured a good number of each in this site, juveniles and adults, which revealed an interesting pattern in both. The smaller specimens of Corydoras sp. clara present more rounded snout whereas the bigger ones present more pointed snout. For what we were calling of CW146, the smaller specimens present few dark marks on flanks and one to two longitudinal dark stripes on dorsal fin (similar to CW111 pattern), while the big guys present the typical CW146 pattern, with flanks densely covered by dark markings and three to four longitudinal dark stripes on dorsal fin. Quite interesting. We preserved most of them in formalin, saving some specimens for photos in life and DNA samples.

On the morning of the next day, Mr. Ohara was taking some photos in life for your delight. I obviously picked the bottle were the Corys were preserved to check our precious material. And another surprise. There was a single pretty different mimetic specimen which seems the mimetic pair of what we identified as CW146. Basically, a dwarf mimic of our CW146. We need to capture more!. Since our goal was the CW111, we started to search in other possible places around there for two days. In one of those sites, we captured tons of babies of our CW146 and juveniles and adults of our dwarf mimic on the sandy banks of a big river. This site presented a stretch with rocky bottom, where we captured some Plecos, such as Harttia cf. dissidens, Hypostomus soniae and Aphanotorulus cf. emarginatus (previously Squaliforma). We also tried a last site before leaving checkpoint 1, a small stream with a large sandy stretch. Sadly, no Corydoras there but a pretty beautiful species appeared, Steindachnerina seriata. It is Worth to mention that Ohara got a good bite of a big Hoplias aimara in this stream.

While moving tho our second checkpoint, we found a very promising site on halfway. An Igarapé (stream) revealed the presence shoals of large-sized Corydoras sp. clara. We captured dozens of them thanks to my loyal castnet. In this clear-water Igarapé I had the pleasure to observe a unique moment. I was chasing a big specimen of Corydoras sp. clara when, suddenly, a medium-sized Hoplias (around 200 mm TL) pounced it. As soon as the Hoplias closed the mouth, it quickly retreated, possibly felting the spines of the Cory. I must confess that I was very proud of the Cory guy/girl: Take that stupid wolf fish. I was alone in this moment and, therefore, you will have to believe in me haha! We also tried to find Corys at the beaches of a large river close to this Igarapé but no luck all. However, a pretty big rapid in this river revealed the presence os beautiPlecos, a new Baryancistrus, Hypostomus gr. plecostomus, Aphanotorulus cf. emarginatus, Hypostomus soniae and Harttia cf. dissidens. Also, I have to do a honorable mention to Hemisorubim platyrhynchos and Hoplias aimara.

We then reached our second checkpoint, a city which most of our sources reported to be the poaching epicenter of CW111. So we headed for the beaches of a large river, and we saw some Corydoras. On that night we were able to get only three specimens. Observing them resulted in an ambiguous feeling. No it was not CW111 or even our CW146 but something else completely different from everything we know. A dwarf species with only diffuse dark markings on flanks (variably presenting dark markings on caudal fin). Additionally, it presents dark dorsal-fin spine and a very distinctive greenish yellow iridescent coloration all over the body. Yes, our fourth species (lets call it Corydoras sp. n. 4 here). Also new.

The second and last site, which was close to checkpoint 2, was simply amazing. A smaller river with rocky bottom stretches and good sandy banks. There was a family of five or six people there, the kids were swimming/playing in the water while mom and dad were fishing/removing guts and scales from their captured fishes. When we arrived there, the man was cleaning (removing guts and scales) a very big Hoplias aimara, my entire hand could easily fit its mouth (I suppose that fish was about 5-6 kilograms). We also saw some Plecos and non-plated catfishes on their small boat, Hopliancistrus and Hypostomus sp. from the H. plecostomus group, and a nice Ageneiosus. I showed a lot of interest in the Hopliancistrus, which was posteriorly donated for me hahaha. The woman said to us that she loves to eat them and even gave us a recipe hahaha! The man threw his cast net more times to see if more Plecos could appear for us but nothing else appeared. A very kind and generous family.

In a quick look on the beaches, we saw big shoals of small Corydoras. But before we begin, I really need to tell you two peculiar events that happened just before our action time. The sun was nearly going by that time when a random couple appeared full of dirty carpets and curtains to wash in our collecting point! Moments later, a man showed up. He said nothing, just headed towards the water, removed only his belt, entered the river with the remaining clothes. After a couple of minutes, he left the water, put his belt and entered his car to go away. Just like that. I felt like I was in an alternate chaotic dimension. Well, going back to the fish...When the night fell, we started then the aquarium sieve plus flashlight hunting. We got a very good number of Corydoras sp. n. 4, a couple of Corydoras sp. clara and a single specimen of what seems to be a baby Corydoras apiaka. Also, we got more Hopliancistrus sp., Harttia cf. dissidens and even a couple of Pseudancistrus sp. Nice Aphyocharax sp. and Crenicichla sp. called my attention. While Britto and I were trying to collect some Characiformes for our friend Cristiano Moreira, Ohara shouted Guys, I collected a pirarucu! The pirarucu is a very emblematic fish in the Amazon, the legendary Arapaima sp. was there in front us. A dream that came true to me, be in the presence of such imposing fish. This was surely a moment I will remember till the end of my life.

Our expedition was nearly ending and it was time to start our return to Sinop. We devoted na additional day in our checkpoint 1 before heading to Mato Grosso. It resulted in the captured of more specimens o four CW146, its dwarf mimic and Corydoras sp. clara. We were a little bit sad because no typical CW111 specimen appeared, which led me to think about some possibilities. I am pondering the following things: (I) the color pattern of what we are calling CW146 is quite variable, specially if you consider ontogeny (juvenile specimens of our CW146 are very similar in color pattern to the typical CW111), (II) CW111 was said to be captured with CW146 by all of our sources (you will also find this information online in some aquarium groups specially from Asia), (III) the few morphological information available (except color pattern of course) on facebook photos are: relatively deep body and huge infraorbital 1, which are both present in our specimens, (IV) the presence of elongated dorsal fin in males is a mark of CW111 but also appeared in recent images of CW146, and (V) both species present (not present in all of the four specimens) a quite uncommon feature in the group (I only observed a similar condition in some C. robineae), the horizontal dark bars on dorsal fin (of course this can be expected in Corydoradinae, since mimycry is going crazy in the group but the mimics generally present conspicuous morphological differences, which is not the case of our material and the specimens depicted on facebook photos also Worth to repeat that we found a mimic species to our CW146 there, clearly different in morphology but very similar color pattern, including the horizontal dark stripes on dorsal fin). I am not confirming that the typical CW111 and CW146 are the same thing but only that we have arguments to consider this possibility. We know other examples of extreme variations in color pattern (e.g. Hypancistrus), and we also know that we can make artificial selection to generate aquarium lineages. Remember, this is not a confirmation but a ponderation.

Finally, I want to express how grateful I am to Ian Fuller, CorydorasWorld and all donators, I have no words to thank you for the RAP initiative! I hope you enjoyed this report and I hope to meet you all soon!

Images Willian Ohara.