Amatolebias wichi new combination.

Etymology: in honor of Wichi indigenous people who inhabit in several settlements very close to type locality, Western Chacoan region.

Amatolebias wichi, described as Austrolebias wichi, from seasonal ponds of the Bermejo river basin in the Western Chacoan district in northwestern Argentina. This species was found in a single pond, a paleochannel of the Bermejo River, which is seriously disturbed by soybean plantations surrounding it. Despite intensive sampling in the area, this species was only registered in this pond where it was relatively scarce. Therefore, we consider this species as critically endangered. This species is the sister species of A. patriciae in our phylogenetic analyses and is similar, in a general external aspect, to A. varzeae and A. carvalhoi. It can be distinguished among the species of Austrolebias by its unique color pattern in males. Additionally, from A. varzeae by presenting a supraorbital band equal or longer than the infraorbital band (vs. shorter) and from A. patriciae by the convex dorsal profile of head (vs. concave). Further diagnostic characters and additional comments on its ecology and reproduction are provided.

The genus Austrolebias Costa comprises species inhabiting seasonal ponds at the Southern portion of Neotropics in La Plata drainage, with one species from the Amazon basin in the Bolivian Chaco. Species of this genus are known from the lowlands in the Chaco-Pampasic floodplains of Argentina, Bolivia, and Paraguay. The genus also inhabits Uruguay (Uruguay river drainage and costal drainages) and Southern Brazil (Uruguay and Iguazu river drainages and costal drainages), where it presents its highest species diversity, probably due to the complex geological history of these regions.

Six species of Austrolebias have been recorded from the Chaco Freshwater ecoregion sensu Hales and Petry. Austrolebias accorsii Nielsen & Pillet, 2015 may also be listed here, because although it inhabits the Amazon basin, the area in which this species occurs has been in contact with La Plata basin

and only recently, in a geological timescale, was captured by the Amazon system . Austrolebias species in the Chacoan region can be geographically divided in two non-overlapping groups, with two species from the Western Chacoan (WC) region (sensu Morrone: A. monstrosus (Huber 1995) and A. vandenbergi (Huber 1995); and four species from the Eastern Chacoan (EC) region, of which two are endemic: A. toba Calvino 2006 and A. patriciae (Huber 1995), and two species shared with the pampasic region: A. bellottii (Steindachner 1981) and A. nigripinnis (Regan 1912). In the present work we describe a third Austrolebias species from the Western Chacoan region which is closely related to A. patriciae, present in the Eastern Chacoan region. Colour pattern and general morphology resembles also Austrolebias varzeae Costa, Reis & Behr, 2004, from the upper Uruguay basin and A. carvalhoi (Myers, 1947), from the upper Iguazu basin. Also we analyzed the phylogenetic relationship of this new taxon based on morphology and a molecular marker.

Alonso et. al. reshuffle the genus in 2023 and elevates the 7 subgenera into genus status and adds 4 genera to the total, making 11 genera from former Austrolebias.

To breed most Austrolebias, you need a tank with about 10 to 25 liter water in it, a small jar or plastic container of about 10 to 15 cm high, a little bit of well-boiled peat moss, or coco-peat, and a water temperature between 18 and 24 C. It is wise to add a small filter to that tank and change the water regularly for 90 %. Bring one male and, if possible, two or more females in the tank and feed the fishes daily with live food like daphnia, red- and black mosquito larvae, and white worms. Austrolebias does not accept dry food quickly, and also, the prepared cow-heart is not preferred if live food is offered. If possible, breed this genus in larger tanks with more than one pair or trio and give some hiding places if you do so. When breeding with more than one male, you should also provide more than one spawning container. Every male must have one, and you will see they show interesting territorial behavior to attract females into their spawning place.

The male "flinders" around the female, displaying his fins high- up with the most intense colors. As the female is willing to spawn, she follows the male, pressing his head towards the layer of peat, and when the female contact the male's belly, both will dive into the peat layer. This layer should have a thickness of at least the length of the largest animal or, better, some deeper so they can dive entirely into it.

The spawning occurs during the whole fertile life of the fishes, starting at 5 to 6 weeks of age, till they become old and weak or die from the lack of water in their natural environment. This "end-of-life" will be within 8 to 11 months, depending on the temperature. Higher temperatures will trigger more rapid aging.

In the wild, Austrolebias live in colder environments during the wintertime. Temperatures in Uruguay, Paraguay, and Argentina can get very low. Incubation time usually is six weeks if stored at high temperatures ( 25 C.) and more extended if kept at lower temperatures. The development can last five to six months also. So it is wise to check the eggs regularly to see if the eyes inside the eggs are fully developed and the iris is well visible. When "eyed-up," put a part of the peat with the eggs in water at cool (ca. 18 C) temperature. If the fry usually hatches- and swims within a few hours, wet the rest of the peat. After hatching, feed the fry immediately with freshly born Artemia nauplii. A day or so later, I pour the water together with the fry off and place them in a well-filtered tank without any peat moss to grow up. Austrolebias are not used to strong currents, and juveniles can die if turbulence is too strong. The remaining peat will still have eggs inside that are not ready to hatch yet. Re-pack the peat and store it for some extra time. This hatching delay is nature's answer to short rain showers that fill pools only temporarily, followed by another dry period. Such an event would kill the entire population of the species in that area if all eggs were hatched with first rains. These (late) eggs will hatch later, sometimes very much later, and the fishes that were born earlier will eat these youngs.

As stated before, young's are growing fast and will produce their first eggs after 5 to 6 weeks already, if not even sooner. This breeding information applies to most Austrolebias. However, if the above Austrolebias- species have different behavior or extreme adult size, find these adaptions below in this chapter under <remarks>.

Remarks;

There are no reports yet on the reproduction of this species but it can be assumed that it does not differ from the general breeding method described above.

Max. size 00 mm in males - female smaller.
Dorsal (average, male only ) 00.0,
Anal (average, male only ) 00.0,
D/A (average, male only ) 0.0,
LL scale count (average) 00.0
Pre- dorsal length to SL – 00.0 %
Depth to SL – 00.0 %
Vertebrae count (average) 00.0

Alonso F., G. E. Terán, P. Calviño, I. García, Y. Cardoso, G. García. 2018. An endangered new species of seasonal killifish of the genus Austrolebias (Cyprinodontiformes: Aplocheiloidei) from the Bermejo river basin in the Western Chacoan Region. PLoS ONE 13(5):  

Alonso F., G.E. Terán, W.S. Serra Alanís, P. Calviño, M.M. Montes, I.D. Carcía, J.A. Barneche, A. Almirón, L. Ciotek, P. Giorgis, J. Casciotta, 2023. From the mud to the tree: phylogeny of Austrolebias killifishes, new generic structure and description of a new species (Cyprinodontiformes: Rivulidae) Zool. Journ. of the Linnean Society, XX, 1-30, Fig. 15, Tab. 2