New Otocinclus

[Silurus]

Lehmann PA, F Mayer & RE Reis, 2010. A new species of Otocinclus (Siluriformes: Loricariidae) from the Rio Madeira drainage, Brazil. Copeia 2010: 635–639.

Abstract

A new species of Otocinclus (Loricariidae) is described from tributaries to the Rio Madeira, in the State of Amazonas, Brazil. The new taxon can be distinguished from its congeners by lacking middle abdominal plates between the lateral abdominal plates, and by having the dark spot at the base of the caudal fin separated from the midlateral stripe by an unpigmented or slightly pigmented area, and not extended posteriorly onto the middle caudal-fin rays.

[Silurus]

In case you are wondering what the name of the new species is, it's O. mangaba.

[Silurus]

Some of the photos currently listed as

Otocinclus hoppei

in the Cat-eLog may actually be referable to O. mangaba, especially those that have a rounded caudal spot (as opposed to diamond-shaped in O. hoppei).

[The.Dark.One]

Hi

Could I have a pdf please?

steven.grant1@virgin.net

Thanks

[The.Dark.One]

Some of the photos currently listed as

Otocinclus hoppei

in the Cat-eLog may actually be referable to O. mangaba, especially those that have a rounded caudal spot (as opposed to diamond-shaped in O. hoppei).

Looking at the images on the clog, all bar the first three look like O. macrospilus to me?

[Mike_Noren]

Some of the photos currently listed as

Otocinclus hoppei

in the Cat-eLog may actually be referable to O. mangaba, especially those that have a rounded caudal spot (as opposed to diamond-shaped in O. hoppei).

Looking at the images on the clog, all bar the first three look like O. macrospilus to me?

I personally suspect that macrospilus and hoppei are one and the same. The diagnostic characters given by Schaeffer is the pigment spot and "meristic differences in numbers of GAP plates and tooth counts". As for the pigment spot there are obvious hoppei and obvious macrospilus, but also countless in-betweens; I do not know how reliable the meristic differences are.

I haven't read the new article (if someone could mail it to me I'd be grateful) but given the variability of the pigment spot it from the abstract sounds as if the lack of a median series of ventral plates is the only way to separate this new species from hoppei/macrospilus.

EDIT: I looked at the cat-elog entry for hoppei, I don't see any fish there I'd consider an obvious macrospilus; on the other hand, neither are any of the photos of macrospilus in the cat-elog. As far as I can tell, and I really must point out that I am not an expert, an obvious macrospilus should look like this.

(Obviously there's still a lot of work to be done on Otocinclus. While looking for a picture of macrospilus I found this attractive venezuelan fish, which is clearly an undescribed species.)

[The.Dark.One]

Hi Mike

I've not seen the hoppei description/Schaefer paper (a pdf would be great if you can and I can send the new species pdf in return) but in terms of macrospilus the fish in the link you say is macrospilus looks very similar to the 'macrospilus' we have on the clog, and the images I refer to on the hoppei page. How are you differentiating said images in terms of representing macrospilus? I have seen tanks of (IMO) macrospilus and they are very variable, but all have a deep body and the large blotch in the peduncle and caudal, and usually have mottling on the dorsal surface of the head and body. See links below to what I consider macrospilus:

http://www.scotcat.com/thedarkone/loric ... spilus.jpg
http://www.scotcat.com/thedarkone/loric ... pilus2.jpg

I've had a quick look at the new description. The head shape of the new species is reminiscent of true vestitus.

[Mike_Noren]

According to Schaefer O. hoppei has a single large circular to diamond-shaped caudal spot, whereas the caudal spot in O. macrospilus is divided into an anterior diffuse triangular spot and a posterior vertical to sickle-shaped spot, separated by an unpigmented discontinuity. However, when you start looking at photos (even just here on Planetcatfish) you'll quickly find intermediates - from "typical" hoppei with large solid spots via fishes with large spots and a hint of a discontinuity, to fishes with smaller spot and a more obvious discontinuity, and eventually "typical" macrospilus with two smaller clearly separated spots.

The photos of both macrospilus and hoppei show individuals with mottled dorsum. Interestingly the photo of the holotype of macrospilus shows a fish with robust caudal peduncle and a large circular caudal spot with just a hint of discontinuity.