Allotoca goslinei

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Original Description: 

 SMITH, M. L. & R. R. MILLER (1987): Allotoca goslinei, a new Species of Goodeid Fish from Jalisco, Mexico. Copeia 3: pp 610 - 616

Etymology: 

  This species is named for William A. Gosline in appreciation for his basic work on sensory canals in cyprinodonoid fishes.

Holotype: 

  Collection-number: University of Michigan Museum and Zoology, Cat. No. UMMZ-213450.

  The Holotype is a mature male of 34.3mm standard length, collected by R. R. Miller, F. H. Miller & D. I. Lyons, 23.02.1976.

Synonyms: 

Neoophorus sp.   Uyeno et al., 1983

Karyotype: 

  The Karyotype describes the number and appearance of chromosomes during the phase of condensation, classified by the position of the centromere (Levan et al., 1964).

The following abbreviations are employed:

 

M = large metacentric chromsome (a result of Robertsonian fusion)

m = small metacentric chromsome (centromere at medium position)

sm = submetacentric chromsome (centromere at submedian position)

smst = submetacentric-subtelocentric chromosome (continous series)

st = subtelocentric chromosome (centromere at subterminal region)

stt = subtelocentric-acrocentric chromosome (continous series)

t = acrocentric chromosome (centromere at terminal region)

 

The Karyotype of Allotoca goslinei, following Uyeno, Miller & Fitzsimons, 1983:

2n = 48    6st/ 42t

Terra typica: 

  The Holotype comes from the Río Potrero Grande, about 10km W of the town Ameca on the road to Atenguillo in Jalisco.

Status after IUCN: 

  not assessed

Status following other sources: 

  Extinct in the wild? Comment: No records since 2004

Distribution and ESU's: 

  This species comes from the Pacific Slope and is endemic to the Río Ameca and its tributary, the Río Potrero Grande from the upper part of the Río Ameca basin in Jalisco.

Habitat: 

  This fish prefers in its habitat areas with current from slight to none (mainly in the dry season). The water is clear to murky in deeper pools. The depths where this fish can be found are less than 1.2m. A few species of vegetation can be identified, mainly water hyacinths, green algae (abundant) and a Nasturtium-like vascular plant. The ground is made of gravel, sand and mud. The fish occur primarily in shallow water (15 - 25cm) beneath floating plants. These (small) patches of floating plants do not reach more than 1m into the pool. In the dry-season, the Río Potrero Grande shrinks down to a couple of pools and swamps. In the spring time, the water-temperatures are between 16 and 20°C.

Colouration: 

  The male shows a dark and elongate spot at midside that lies above the posterior half of the pelvic fin. There may be one or two similar spots anteriorly. Posterior to the single spot are about nine blotches and irregular vertical bars and five or six anteriorly, but these blotches and bars appear only in preservation and juvenile specimens. The living female shows typically three dark spots on the midside, one in the same position as in the male and two positioned anteriorly. The most anterior one lies in front of the pelvic-fin insertion. The female has also got a black spot at the anal-fin origin and a smaller one on each side of the vent. In alcool, adults show (at maximum) 18 irregular bars along the midside. It is these numerous lateral bands in both sexes that is reflected in the common english name of this species, Banded Allotoca.

Biology: 

  Miller measured 16.4 - 20°C from mid-February to early March. The smallest fish taken at this time had been 21mm SL on 4 March. Sixteen newborn young from a wild-caught female from this collection were 9.3 to 12.1mm long.

Diet: 

  The dentition is similar to other members of the genus Allotoca, means conical teeth as an outer row of large teeth, followed by a narrow band of smaller inner teeth. This suggests this species is hunting for small invertebrates and probably insects from the water surface.

Remarks: 

  Allotoca goslinei has been only taken from a quiet pool that was 23m long and between 3 and 4m wide. This was the terminal pool before the creek emerged from the canyon and dropped precipitously to the Río Ameca.

 

  Like the sympatric living Allodontichthys polylepis, this species has disappeared from the Río Potrero Grande a few years ago by unknown reasons and has been thought to be extinct in the wild, but recently, it has fortunately been re-detected in upper tributaries (Domínguez, pers comm, 2011). Nevertheless it is extremely endangered.

 

  Allotoca goslinei is closely related to Allotoca dugesii and (probably) maculata. These three species together seem to form a kind of sistergroup to the remaining four closely related species from the lagos de Pátzcuaro, Zirahuèn, Zacapu and the Río Santa Catarina (catarinae, diazi, meeki and zacapuensis).

 

  In 2008, O. Dominguez started a semi-captive conservation program with the help from the Fish Ark Mexico Project. An artificial pond on the area of the Botanical garden of the Faculty of Biology from the University of Morelia has been built and populated with Neotoca bilineata and Zoogoneticus tequila in April, as well as Allodontichthys polylepis and Allotoca goslinei in August. Though there had been troubles with goslinei in this pool at the beginning, in 2010 it has been present in catches again.

 

Husbandry: 

  Looking on the former biotope of Allotoca goslinei, it suggests the species may prefer a habitat with moderate to swift current, structured with gravel, rocks, roots, branches, fallen leaves and river bank vegetation. Fry is eaten in most of the cases, but it may depend on the quantity and quality of food and on the number of space to hide. When several different stages of juveniles occur, fry may be neglected, so it makes sense to add separate brought up fry to the group with a size of 1.5 or 2cm to provide these stages and get a flock breeding colony.

 

 The recommended tank size is at least 100 liters, bigger ones with a generous base and little height (25cm are enough) are better for sure. With rocks and vegetation in the corners and backsinde of the tank well structured tanks combined with some roots and/ or wood seem to do best with this species. The current should be moderate or swift. 

 

 In the wild, the species seem to feed from small or middle - sized invertebrates like bloodworms or insect larvae, so feeding with similar food, Daphnia, Mysis and other food from animalistic sources will be best for this predatory fish.   

 

 Concerning water quality, this species is in need of greater water changes (60 - 80% every week) like most of the Goodeids, especially river and spring inhabiting species, so an automatic water changing system can be helpful. Otherwise, in combination with constant temperatures higher than 24°C, fish may get sick, lose resistance against diseases and age too fast. So for keeping the strain healthy and strong, give the fish a rest during winter time with temperatures lower than 20°C for 2 or 3 months so they stop producing fry. Allotoca species can be kept down to temperatures of 15 or 16°C without problems for months, some species even lower. In spring, when the temperature slowly increases, they will start spawning at 20 or 21°C and won't stop until it gets colder again or when it gets too warm (25°C?).

 

 This species is doing very well when is kept in the open from spring to fall, starting when the temperature exceeds 15°C water temperature and cold periods are no longer expected. During the warm summer, reproduction will stop and may occur again in fall. Bring the fish in before the temperature goes below 10°C water temperature and keep them cool for the first days, then slowly raise the temperature but try to stay below 20°C over the winter time.

First Describer: 
Smith & Miller, 1987