"Xenotoca" doadrioi

Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Xenotoca doadrioi
Original Description: 

  Domínguez-Domínguez, O., Bernal-Zuñiga, D.M. & Piller, K.R. (2016): Two new species of the genus Xenotoca Hubbs and Turner, 1939 (Teleostei, Goodeidae) from central-western Mexico. Zootaxa 4189 (1): pp 081–098

Etymology: 

  The name of the species, an adjective, is derived from the name of the prestigious ichthyologist Dr. Ignacio Doadrio, Museo Nacional de Ciencias Naturales, Spain, who has strongly contributed to the study and
knowledge of Mesoamerican fish diversity.

Holotype: 

  Collection-number: Colección de Peces de la Universidad de Michoacán, Cat. No. CPUM-9589, CPUM-T-41530

  The Holotype is an adult male 41 mm SL, collected the 17th of June 2010.

English Name: 
San Marcos - Redtail Splitfin
Mexican Name: 
Mexclapique de San Marcos
Synonyms: 

Characodon eiseni    Rutter, 1896

Characodon variatus    Regan, 1907

Xenotoca eiseni    Fitzsimons, 1972

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" doadrioi has not been ascertained, but is presumably similar to the one of "Xenotoca" eiseni.

Size: 
Maximum known standard length: 47mm
Terra typica: 

  The type location is a middle sized pond at San Sebastian village, North to Etzatlan, Jalisco, Mexico (20°49’25"N and 104°7’10.8’’W). This location belongs to the Etzatlán endorheic drainage.

Status after IUCN: 

  not assessed

Status following other sources: 

  not assessed; after Domínguez et al. (2016): Critically endangered

Distribution and ESU's: 

  The species is endemic to the endorheic region of Etzatlán, in the state of Jalisco, Mexico. The type locality is a small and permanent pond just in the east end of the Hacienda San Sebastian, with around 6,000 m2 fed by a spring (20°49’25’’ N, 104°7’10.8’’ W). Other known locations in the area are Almoloya spring, Estancia de Ayoles reservoir, Oconahua Dam around 3km west of Oconahua village, and the highly perturbed and seasonally affected streams along the federal road number 4, between Etzatlan and San Marcos Village, known as arroyo San Marcos and arroyo de la Granja Sahuaripa, but the last two locations have not yielded specimens since 2006, and in an extensive survey in 2015, these localities were found to be totally dry or full of Pseudoxiphophorus bimaculatus (Heckel 1848) when water was present.

 

  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" doadrioi, it is not possible to distinguish different ESU's, so there is only one recognized: Xendo1 (before: Xenei5).

Habitat: 

  This species seems to be highly adaptable to variable habitat conditions. At the type locality, the species inhabits an area with turbid water, and was collected in a shallow water no more than 1.5 m deep. The pond is no more than 3 meters at its deepest part; the bottom is comprised of mud and gravel, and no water plants are present. Other fish species collected in the area were "Xenotoca" cf. melanosoma, Goodea atripinnis (Jordan 1880, Poeciliopsis infans (Woolman 1894) and the introduced Xiphophorus variatus (Meek 1904) and Oreochromis sp. Historically, other species reported from this pond include Algansea amecae Pérez-Rodríguez, et al. 2009, Moxostoma austrinum Bean 1880, and Allotoca maculata Smith & Miller 1980, but all of these species have not been collected in the area since 1970. In the El Moloya Spring, the species inhabits clear water with gravel to muddy bottom and water plants and this pond is used as a swimming pool. Other species inhabiting this pond are "Xenotoca" cf. melanosoma, Zoogoneticus purhepechus (Domínguez-Domínguez et al. 2008), Ameca splendens (Miller and Fitzsimons 1971), Goodea atripinnis, Poeciliopsis infans, and the introduced Oreochromis sp. In Oconahua Dam, the water is turbid and contains a muddy bottom and with few water plants. Other species collected include "Xenotoca" cf. melanosoma, Goodea atripinnis, Poeciliopsis infans, as well as the introduced Lepomis macrochirus (Rafinesque 1818), and Cyprinus carpio (Linnaeus 1758). The San Marcos stream is a seasonally fluctuating stream that is dry for most of the year, but when water is present the surface of the stream is totally cover with Eichhornia crassipes (Martius), Thypa sp., and Cyperus sp. The water at this site is highly polluted by organic matter and is turbid, whereas the Sahuaripa stream is an irrigation channel totally modified and fed by a water pump; in 1999 and 2002, the species collected in bothplaces included "Xenotoca" cf. melanosoma, Allotoca sp., Goodea atripinnis, Poeciliopsis infans, and Oreochromis sp. For the 2006 survey, Allotoca sp. was not collected; in the 2015 survey only Pseudoxiphophorus bimaculatus was found.

 

Hacienda San Sebastian IHacienda San Sebastian II

 

Balneario Al Moloya IBalneario Al Moloya II

Colouration: 

  When alive, the coloration varies with respect to the age and sex of the organism. Mature females display a general brownish coloration. Most mature females display dark blotches along the central part of the body, being bigger and conspicuous at the posterior half of the body; these blotches are formed by small black spots. Some scales show iridescent silver colorations in the body, being more evident in the postorbital and opercular region. Some females possess a dark stripe that runs along the middle part of the body, from the opercle
to hypural plate. Scales are frequently rounded at their exterior margin by small black spots; a black blotch is
present in the posteroventral region, between the pelvic and anal fins, which varies in depth and width. Juveniles have the same coloration as females, but as they reach ±20 mm, they begin to differentiate to adult coloration. Males show the most colorful form of all Xenotoca - species; this varies depending of the size and reproductive stage. In general, the caudal peduncle has an orange to almost red coloration combined with iridescent blue scales, the intensity and coverage of each color along the caudal peduncle is highly variable, some specimens show a blue or green to dark blue or green scales in the anterior part of the peduncle, the blue or green coloration extends to the origin of the dorsal fin, and also the intensity and coverage is highly variable, the caudal fin and frequently the anal and dorsal fin also have orange to red coloration in the base and sometimes the dorsal fin shown a dark coloration in the base. The portion of the body from the origin of dorsal and anal fin to pelvic or pectoral fin is pale in coloration, with gray to yellowish coloration, in the pre-ventral region. Orange to red coloration exists frequently and extends to the inferior part of the head. Just up to the pectoral fin there is a black blotch with iridescent scales that also is highly variable in intensity and size. There Is also blue iridescent coloration in the opercle and in some scales along the body. The coloration of preserved specimens varies with respect to fixation and time since fixation, but in general, female specimens preserved in 5% formalin possess clear brownish coloration. The blotches are less evident along the body, in larger females they are still present. Numerous dark small spots are found in all the upper half of the body. A silver stripe is present along the middle part of the body, being more evident in the posterior half. The dark blotch in the posteroventral region is still evident. The opercle shows a silver coloration. Males lose all coloration when preserved. The peduncle and pre-ventral region show a clearer brownish coloration. The rest of the body shown a more brownish dark coloration with numerous black spots distributed along the upper half of the body. Fins clear and unpigmented, a few specimens still show a dark blotch up to the pectoral fin and the scales are rounded by a numerous black spots.

Biology: 

  Nothing is known about its biology in nature. Concerning the closely related "Xenotoca" eiseni, we have the following information: Young are produced at least in March and April and probably over a long reproductive period. In aquatic stocks, broods have appeared in all months of the year, maintained  at 24 - 27°C.

 

  On a survey in February 2016, Koeck et al. found this species at the type location in turbid, milky and murky water, where the species was sparse. We could not detect any fry, smallest specimens were about 3.5cm TL. We found the species also in the outlet, a small milky creek, covered by trees above mud and branches. At Almoloya - spring, we were able to find only one male, the water was turbid and muddy. The species seems to be extremly rare at this location.

Diet: 

  Adults have got strongly bifid teeth in the outer row and conic teeth in the inner row. Following Fitzsimons (1972), the closely related species "Xenotoca" eiseni is omnivorous, although plant material forms the greater volume of food. The gut is as long or sligthly longer than TL. Besides plant material, they feed also from worms, crustaceans, spiders and aquatic insects.

Remarks: 

  "Xenotoca" doadrioi is known only from small springs and a dam in areas highly impacted by human activities that have been strongly modified for irrigation. It has been extirpated from more than 50% of the known historical localities (Pedraza-Marrón 2011). This species is found in small numbers in the three localities where it presently occurs, and these localities are under the influence of substantial irrigation pressure for agriculture. Introduced fish species pose a significant risk for the long - term survival of this species. It is recommended that is has to be considered as a species in danger of extinction.

 

  All five different collections we keep in Europe and the United States refer to the arroyo San Marcos and the arroyo Sahuaripa, which are adjacent and coalesce after a few kilometres. To the same drainage belongs the Presa de Oconahua. All these five locations are located no more than 3 kilometres apart of each other, the Presa de Oconahua is a few kilometres downstreams.

Husbandry: 

  Looking on the habitats of "Xenotoca" doadrioi, they suggest the species is not in need of a special habitat structure as many of the locations show no or little vegetation but murky water. Nevertheless, it may prefer dense vegetation and roots (in the aquarium even dense artificial staff) to hide. In the wild, there was little or no current to observe in the biotops, so it won't be necessary in the aquarium as well. 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" doadrioi can be fed in the aquarium with food of different sources, composed of different small frozen or freeze dried invertebrates (Daphnia, Bloodworms, Artemia), small livefood (e.g. Nauplia, Cyclops, Daphnia) and good flake food or tablets respectively granulat food. Fish of the "Xenotoca" eiseni - complexe feed from more vegetarian sources than representatives of the "Xenotoca" melanosoma - complexe.

  In some cases, "Xenotoca" doadrioi could be observed attacking tales of other fish, not only Guppys but also Goodeids (e.g. Allotoca diazi, pers. obs. Köck). However, this species does better in its own tank.

  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 17°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 15°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