Xenotoca variata

Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Xenotoca variata
Original Description: 

  BEAN, T. H. (1887): Descriptions of five new Species of Fishes sent by Prof. A. Dugès from the Province of Guanajuato, Mexico. Proceedings of the United States National Museum 10: pp 370 - 375

Etymology: 

  The specific epithet variata is derived from the Latin means "variable". Bean explained not, why he had chosen that name; maybe because the colour is changing in sunlight, so it doesn't appear steady (but this is only the fact with males and variata had been described from females, so: On the other hand, Bean gave the description of the colouration with: "on the sides are several - differing in shape, size and number - dark blotches", so maybe the name refers to the blotched appearance of the females (the type-specimens).

Holotype: 

  Collection-number: United States National Museum, Cat. No. USNM-37809.

  The types are females of 65.5mm standard length, collected by A. Dugès, collection date unknown.

English Name: 
Jeweled Splitfin
Mexican Name: 
Pintada
Synonyms: 

Characodon variatus    Bean, 1887

Characodon ferrugineus    Bean, 1887

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 Xenotoca variata, following Uyeno, Miller & Fitzsimons, 1983:

2n = 48    4st/ 44t    

Size: 
The maximum known standard length is 90mm (Miller et al., 2005).
Terra typica: 

  The types came - following Bean - from the "Province of Guanajuato".

Status after IUCN: 

  not assessed

Status following other sources: 

  Staus: Low risk

  Comment: Likely represents 2 spp.

Distribution and ESU's: 

  This species inhabits the ríos Lerma and Grande de Santiago basin (Pacific Slope) and the Río Santa María drainage (Atlantic Slope), an upper tributary to the Río Pánuco. This species lives widely distributed in the states of Aguascalientes, Guanajuato, Jalisco, Michoacán, Querétaro and San Luis Potosí. Populations from the endorheic Río Grande de Morelia drainage, including the Lago de Cuitzeo belong to a distinct but not yet described species (Xenotoca cf. variata).

 

  ESU ist short for Evolutionarily Significant Unit. Each unit expresses an isolated population with different genetic characteristics within one species.  ESU's can be defined by Molecular genetics, Morphology and/or Zoogeography and help in indicating different phylogenetic lineages within a species. The abbreviation for an ESU is composed of the first 3 letters of the genus, followed by the first 2 letters of the species name and an ongoing number in each species.

 

  In Xenotoca variata we actually are able to distinguish four different ESU's. To Xenva1 belong all populations from the Río Santa Maria drainage and populations along the middle and upper Río Lerma downstreams to the Río Grande de Santiago basin (Río Verde). Xenva2 is restricted to the Los Negritos ponds east of the Chapala lake, whereas Xenva3 is used for the specimens of the Lago de Zacapu and its drainage. Xenva4 encompasses fish from the Aguanaval drainage, a system in the state of Zacatecas and now isolated from the Río Grande de Santiago system but flowing northwards into the endorheic Bolsón de Mapimi area. Xenva5 is still in use for the not yet described species from the endorheic Río Grande de Morelia /Lago de Cuitzeo basin.  

Habitat: 

  Xenotoca variata prefers habitats like clear to murky rivers and lakes with currents of moderate to absent. It can be detected in shallow water (less than 1m deep) over substrates from deep mud to rocks. Usually, vegetation is abundant. Detected genera have been (besides much floating or attached green algae) Potamogeton, Eichhornia, Nasturtium and Myriophyllum. 

 

Jesus Maria dam IJesus Maria dam II

 

Atotonilco IAtotonilco II

 

Atotonilco IIIAtotonilco IV

 

Los Negritos ILos Negritos II

 

Laguna Zacapu ILaguna Zacapu II

 

Laguna Zacapu IIILaguna Zacapu IV

Laguna Zacapu V

Laguna Zacapu VI

San Pedro Puruátiro ISan Pedro Puruátiro II

Manantial en Agua Caliente IManantial en Agua Caliente II

Manantial en Las Cruces IManantial en Las Cruces II

Presa en Las Cruces IPresa en Las Cruces II

Río Guanajuato IRío Guanajuato II

 

Lagoon at Lagos de Moreno ILagoon at Lagos de Moreno II

Colouration: 

  Females are coloured grayish-brown, slightly darker on the back. On the sides are several - differing in shape, size and number - dark blotches, forming a midlateral band in in older females, dusky on the head and more prominent posteriorly. Males are coloured grayish-green on the back and white to yellow on the venter. The unpaired fins are dark gray, the caudal fin nearly black with a flashing yellow terminal band. The dorsal fin has sometimes got a bright band, too, whitish to yellowish. The anal fins may be coloured yellow instead of gray. A different number of big greenish or yellowish glimmering scales cover the sides.

Biology: 

  Captures of young or pregnant females indicate that the reproduction occurs from at least February through May.

Diet: 

  Mouth, jaws, gut and dentition suggest omnivorous feeding habits, but he length of the gut differs in length ( between 1 and 1.5 times the size of the body) as well as the food-preferences, depending on the nutrition available (prefering carnivorous food), from water insects and fish-fry to algae.

Remarks: 

  The populations reported from the Lago de Cuitzeo and the Río Grande de Morelia - basin differ from Xenotoca variata in some details. These fish are in description to be a separate species (pers. com. Dominguez 2011). It will be named in honour of the late Ivan Dibble. The remaining populations are forming 4 phylogenetically clear distinguishable lineages, one comprising the populations from Zacatecas, one from the Chapala-Lake area (Los Negritos), a third one from the Zacapu lake and the forth encompassing populations from the ríos Lerma (middle) and Panuco basins, with little prospects to separate Lerma and Panuco populations.

 

  Bean described Characodon variatus from females and Characodon ferrugineus (that he thought to be a different species) from both sexes. Five years later, he recognized his mistake and synonymized both species.

 

  "Xenotoca" eiseni has been erronously synonymized with variata because in preservation (without seeing the striking colouration) both species differ slightly in the meristic characters. However, Fitzsimons in 1972 detected that both species are valid.

 

  After recent studies (Webb, Dominguez, Piller), Xenotoca variata and the undescribed species cf. variata will be the only remaining species in this genus. The four other described species of Xenotoca (doadrioieiseni, lyonsiand melanosoma) as well as another undescribed species, cf. melanosoma, belong to a different but undescribed genus.

 

  Xenotoca variata is one of only four species reaching the Río Pánuco system on the Atlantic Slope, that is draining to the Atlantic Ocean. It can be found sympatric with Xenoophorus captivus and Goodea gracilis in the Río Santa María.

 

  Though this species resembles Chapalichthys pardalis and Ameca splendens in their appearance abit, all three species won't crossbreed when kept together.

Husbandry: 

  Looking on the habitats of Xenotoca variata, they suggest the species is not in need of a special habitat structure as some of the locations show no or little vegetation, whereas others do, with clear to murky water. Nevertheless, it may prefer dense vegetation and roots (in the aquarium even dense artificial staff) to hide. In the wild, there was medium strong to no current to observe in the biotops, so it won't be necessary in the aquarium to provide strong current. In the aquarium, the fish rarely hide in the shelter, but courting and impressing males as well as fighting fish of both sexes can often be seen in the open water. Fry is eaten in some cases, in others not, so 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 is often 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 are better for sure. Dense vegetation combined with many roots and wood and free space areas for the males to impose and fight make sense. The current should be low.

 

  In the wild, the species seem to feed as a typical omnivore from small invertebrates, aufwuchs, algae, organic matter and insects from the surface. Xenotoca variata can be fed in the aquarium with food of different sources, composed of different small frozen or freeze dried invertebrates (Daphnia, BloodwormsArtemia), small livefood (e.g. Nauplia, CyclopsDaphnia) and good flake food or tablets respectively granulat food.

 

    Concerning water quality, this species is in need of greater water changes (60 - 80% every week), 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 burn themselves out. So, mainly 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. 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 gets too warm (25°C?).

 

  This species does 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 12°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.

Locations