Allodontichthys zonistius

Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Allodontichthys zonistius
Original Description: 

  HUBBS, C. L. (1932): Studies of the Fishes of the Order Cyprinodontes. XI. Zoogoneticus zonistius, a new Species from Colima, Mexico. Copeia, 1932, No. 2: pp 68 - 71

Etymology: 

  The epithet can be derived from the Greek and means: "with a banded sail", which is referring to the black-banded dorsal fin: ζώνη (zona = zone, belt or banding) and Ιστίον (istion = sail)

Holotype: 

  Collection-number: Museum of Comparative Zoology, Cat. No. MCZ-32818.

  The Holotype is an adult male of 44mm standard length, collected by Gustav Glückert and donated to the Museum on 01.11.1913.

English Name: 
Bandfin Splitfin
Mexican Name: 
Mexclapique de Armería
Synonyms: 

Zoogoneticus zonistius   Hubbs, 1932

Alloophorus zonistius     Turner, 1937

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 Allodontichthys zonistius, following Uyeno, Miller & Fitzsimons, 1983:

2n = 48    2m/ 2s/ 44stt  

Size: 
The maximum known standard length is 63 mm (Miller et al, 2005).
Terra typica: 

  Carl L. Hubbs only mentioned, that the two specimens of the description (Holotype and Paratype) were collected in Colima, Mexico. C. L. Turner (1946) specified the type location a bit more with " a tributary of the Río Colima near the city of Colima".

Status after IUCN: 

  not assessed

Status following other sources: 

  Status: Vulnerable

  Population development: Stable since 2000

Distribution and ESU's: 

  This species comes from the Pacific Slope and is endemic to the Río Armería and two tributaries to the Río Coahuayana in Jalisco.

 

  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 Allodontichthys zonistius, it is not possible to distinguish different ESU's, so there is only one recognized: Aldzo1

Habitat: 

  Like all other Allodontichthys-species, the Bandfin Splitfin can be found characteristically in clear riffles over substrates of gravel, rocks and boulders. It goes down to a depth of 1m, but prefers absolutely depths of less than 0.5m. During the dry season, the currents are slight to moderate, but surely turbulent during the rest of the year. The only form of vegetation associated with this species are green algae. In some areas, there can be found a lot of dead foliage where this species uses to hide beneath.

Colouration: 

  The females and males have the upper part of the body above the lateral line spotted with dark brown. The scales are blackened posteriorly, the obligate black comma-shaped Allodontichthys-spot behind the opercle is marked. Five black bars are crossing the dorsal fin, bordered narrowly by whitish. All females have wide, dark and fairly regular bars beginning well above the lateral line and extending well below the lateral line. There are 10-12 of these bars, the first just back of the eye and the last at the anterior end of the caudal fin. These markings have a rounded posterior and a straight anterior margin.  The sides (of alcohol specimens) are purplish, except on the yellowish silver lower surface. The cheeks are golden, the opercle is greenish, the top of the head and muzzle is purple. The caudal fin has a light yellowish crescent behind a diffuse dark basal blotch; behind the light bar the fin is abruptly darkened by black membranes. The other fins are somewhat dusky.

Biology: 

  Turner collected gravid females on 2 April 1946 near Colima, so this species might reproduce from winter to the early spring.

Diet: 

  The conical teeth and the short gut indicate carnivorous feeding habits. The examinations of Turner found the guts of the related Allodontichthys tamazulae containing large insect larvae. Probably all species of Allodontichthys feed from insect larvae from the bottom of their habitats, detected between algae, slick and rocks.

Remarks: 

  Allodontichthys zonistius had been the first described Allodontichthys. First of all, it had been placed in the genus Zoogoneticus by Hubbs in 1932, but shortly afterwards transferred into a new genus, described by Hubbs & Turner in 1939, mainly because of its divergent dentition. Nevertheless, the narrow relationship to Ilyodon, though assumed, had not been proved because of the missing of a female to study the ovarian characters. Turner collected the first females in April 1939 in the Río Colima and studied the ovarian characters and trophotaenial features in unborn fry. He detected the relationship with Ilyodon and published the new perceptions in 1946.

 

  In 2004, this species had been included into a study about helminthic parasites in fish from the Rio Ayuquila.

 

  In the hobby can be found fish from 2 localities: One from the Río Ayuquila and another from the Arroyo Ahuacapan, that waters into the Río Ayuquila. Though both localities are quite close, aquarists report from characteristically differences in colouration, fertility, shape and behaviour of both populations. Further examinations should take place, wether both populations are really as close as presumed.

Husbandry: 

  Looking on the biotopes of Allodontichthys zonistius, they suggest the species may prefer a habitat with moderate to swift current, structured with gravel, rocks and boulders. Most breeders observed a high level of aggression between the adult fish, so the tank set up should prevent the fish from seeing each other most of the time. 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. Unfortunately, it was not able until now to breed bigger colonies so this statement is made from the comparison with related species and the personal comments of successful breeders.

 

 The recommended tank size is at least 150 liters, bigger ones with a generous base and little height (25cm are enough) are better for sure. With rocks 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 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. 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 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 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.