Alternative name Anablepsoides obscurus.

December 2013 a new species was described by Costa with the name Anablepsoides gamae. This is something confusing as the image in the description is excactly showing the fish to the right.

It seems that the species was synonymized in a in checklist paper published in 2003 by Costa as a book chapter of a book about Neotropical fishes. Question is what this species must be named now.

In the following text you will find what was written, word by word, by Dr. Jean Huber, France, in his wonderful Killi-Data-Online about the difficulties scientists have with the justification of the correct name of this small Rivulus.

Killi Data is the most complete site for scientists and hobbyists on the subject of all Killies in the new- and old world. It is a must for all people who have by any means interest in this group of fishes and in Nomenclature in general.

For a small yearly amout of only 6 euro you can become a member of this group of killi enthausists and have full access to the most complete info on killies, not only the species from South America as in this site but from all over the world.

Citate:

"Rivulus obscurus and ornatus : this is a complicated case and a confusion due to the simultaneous publications of 2 authors (end of 1992 and beginning of 1993, without knowing the project of each other): first, the author's Rivulus book [Huber, J.H. 1992. Review of Rivulus. Ecobiogeography - Relationships. Cybium Suppl., Société Française d'Ichtyologie Publ.: 586 pp., 40 pls., 85 figs., 8 tabs, 13 maps.] where lectotypes of ornatus and obscurus are designated ; and second Costa's paper in DKG Journal [Costa, W.J.E.M. 1993. Zur Identität und Verbreitung von Rivulus ornatus und Rivulus punctatus. D.K.G. (Deutsche Killifisch Gem.) J., 25 (3): 44-46, 2 figs.] where he mentions that the true ornatus is in fact obscurus according to material from near Manaus (3.130S, 60.020W) and the aquarium ornatus is then an unknown species, without knowing the lectotype designation for ornatus from Silves, i.e. not in the area of Manaus ; this is unfortunate and lies only in the lack of communication between Costa and Huber ; but the problem actually comes from the fact that in his descriptions, Garman (1895) used several lots for ornatus with 3 different and distant localities and one lot for obscurus with a type locality near Manaus, identical with one of the 3 for ornatus : in details for ornatus, the 3 localities are Silves, Lake Saraca, N. Brazil {2.880S, 58.350W} ; Parana do Janauari, Brazil {3.200S, 60.080W}  (near Manaus); Lago Cudajas, now L. Badajos, N. Brazil {3.250S, 62.780W} and for obscurus, Lago Januaria, vicinity of Manaus, N. Brazil {3.200S, 60.080W} ; by selecting Silves as the official type locality for ornatus, without knowing Costa's research,

Huber made Costa's publication inappropriate because Costa allocated ornatus to a fish we do not know if it is identical with the fish from Silves ; let's wait until live material is collected from the 2 fixed type localities, Silves for ornatus, and Januaria, near Manaus for obscurus and the issue can be fixed which, in turn, will enable to address another issue, the identification of the aquarium strains of ornatus: one as an aquarium import from Obidos (?), lower Amazon (NSC-2), Brazil {1.920S, 55.520W} and the other from Padre Isla, Iquitos, Peru {3.620S, 73.700W}"

End of citate.

Rivulus obscurus together with Rivulus atratus were placed by Huber in the, at that time, subgenus Rivulus, since 2011 the genus Rivulus, that was erected for this small fishes in the first place.

The species was discovered by Louis Agassiz on October 27 1865 at Lago Hyanuary, about 50 km northwest of Manaus on the eastern bank of the Rio Negro, Amazonas, Brasil.

The given name by Garman was referring to the dusky- dark pigment on the species and for that in Latin "obscurus".

In his book "Review of Rivulus, Ecobiogeography - Relationships" Huber redescribed the species in 1992.

Type series: Lectotype: MCZ (Harvard) 6853 ( juvenile female, 18.2 mm S.L.). Paralectotypes: MCZ 98664 (ex. MCZ 6853) 2 females. Belongs to the genusRivulus. Sympatric taxa are: Fluv. pygmaeus (or Fluv. ornatus), Rivulus ornatus, Rivulus strigatus and Moema staecki.

Keeping and breeding is not easy and a good cover of the aquarium is necessary because there ability to jump, even true the smallest opening, is unbelievable.

This species can, if there is enough space for them, housed in a tank with more males than one only and several females. If separated before and brought together again however, they can be very agressive to each other and fight to become dominant to others. The best way to have much offspring is to put a group or an trio in a shallow tank from 30 liters with a small filter in it or with some airation. On the bottom some peat moss or dark gravel and a floating "mop" to give space for laying there eggs. Very good results are recorded if the species has lots of Riccia fluitans or other floating plants like Azolla used as hidingplaces and by leaving the eggs and later the fresh born juveniles in the tank with the parents. The fish will, if they become a rich varity of small sized life food, spawn during there whole adult life and a good pair produce daily between 3 to 8 eggs.

If not set up as explained above the eggs should be collected by hand and stored for about 14 days in a small container. Eggs are 1.6 mm and amber colored. It is wise, to add to the water you store the eggs in, some acryflavine to provent fungus coming up.

After hatching the young fry can eat fresh artemia nauplii after a week and will live also from small infusoria that are attached to the plants. It takes 4 to 6 months to raise them to maturity.

There lifespan can be up to 3 years in captivity. Eggproduction is at the highest if the fishes are young.

Remarks :

The species dwells at the upper level of their habitat that is almost always shallow- to very shallow in leaf covered puddles aside the larger waterbodies. Lives also on riverbanks in open water and not only in creeks.. The species however is not "floating' like its counterpart Rivulus atratus.

Collecting localities:

Between Lago Murumuro & Parana da Janauaca, Brazil, by Bayley in 1977.

Cabec. da Serrinha, L. Jacaré, Rio Trombetas, Brazil, by EPA in 1969.

Lagoa Janauaca, S.W. Manaus, N. Brazil, by Bitter in 1988.

Manaus, mouth Rio Negro, Amazonas state, Brazil, by Haseman in 1909.

Rio Curui-Napui, Para, Brazil, Anonym in 1968.

Rio Unini, down the rapids, Brazil, by Axelrod in 1988.

Max. size 4.0 cm.
Dorsal 7.0,
Anal 10.1,
D/A 12.0,
LL scale count (average)30.1
Pre- dorsal length to % SL – 79.0 %
Depth to % SL – 17.0 %

Axelrod, H.R. 1989 Trop Fish Hobbyist, 37 (10): 38-52.

Costa, W.J.E.M. 1990c. Ref. fr. Aquariol. Herpétol., 17 (2): 41-44, 5 figs., 1 tab.

Costa, W.J.E.M. 1993b, DKG (Deutsche Killifish Gemeinschaft) J. 25 (3) 44-46, 2 figs.

Costa, W.J.E.M. 1998e. J. Comp.Biol., 3 (1), December: 33-92, 37 figs.

Eigenmann, C.H. 1911. Ann. Carnegie Mus., 7:299-313.

Garman, S.W. 1895. The cyprinodonts. Mem. Mus. Comp. Zool. Harvard, 19 (1): 140.

Henn, A.W. 1916. Ann Carnegie Mus., 10 (9): 93-142, pls.18-21.

Hrbek T. & A. Larson. 1999. Evolution, Lauwrence, Kansas, 53:1200-1216., 7 figs., 3 tabs.

Huber, J. H. 1992. "Review of Rivulus, Ecobiogeography - Relationships" p. 336 - 339.

Huber, J. H. 1992. Cybium Suppl., Société Française d'Ichthyologie Publ.: 586 pp.,40 pls., 85 figs. 8 tabs, 13 maps.

Huber, J. H. 1998d. Société Française d'Ichthyologie: 109 pp., 17 figs.

Ihering, R. von. 1931. Archivos do Instituto Biologico de defesa agricola e animal, 4:243-280, 20 fig., 4 pl.

Steack, W. 1994b. Aquar. Terr. Zeit. (D.A.T.Z.), 47 (11): 692-696, figs.