Allotoca diazi

Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Allotoca diazi
Original Description: 

  MEEK, S. E. (1902): A contribution to the ichthyology of Mexico. Publication. Field Columbian Museum 65, Zoological Series. 3 (6): pp 63 - 128

Etymology: 

  Meek named the species for Porfirio Diaz, President of the Republic of Mexico from 1876/77 - 1880 and again from 1884 - 1911.

Holotype: 

  Collection-number: Field Columbian Museum, Cat. No. FCM-3618.

  The Holotype is an adult female of 66mm standard length, collected by S. E. Meek and F. E. Lutz, 19. - 24.05.1901

English Name: 
Pátzcuaro Allotoca
Mexican Name: 
Chorumo
Synonyms: 

Zoogoneticus diazi   Meek, 1902

Zoogoneticus miniatus   Meek, 1902

Neoophorus diazi   Turner, 1937

Neoophorus diazi diazi   de Buen, 1942

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 diazi, following Uyeno, Miller & Fitzsimons, 1983:

2n = 46    2M/ 4st/ 40t  

Size: 
The maximum known SL is about 120mm (Miller et al, 2005).
Terra typica: 

  The Holotype comes from the Lago de Pátzcuaro, Michoacán.

Status after IUCN: 

  Critically endangered

Status following other sources: 

  Endangered; Comment: Only remnant populations

Distribution and ESU's: 

  This species inhabits the endorheic basin of the Lago de Pátzcuaro, including the Lago de Chalco, Michoacán.

 

    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 three letters of the genus, followed by the first two letters of the species name and an ongoing number in each species.

 

  All populations of Allotoca diazi belong to one ESU: Altdi1.

Habitat: 

  This fish can be found in lakes, spring-fed creeks and ponds in clear  to muddy water, the currents are none to moderate. The substrates in the habitats are mainly mud, sand and rocks and the vegetation includes species of Potamogeton, Myriophyllum, Eichhornia, Lemna, Chara and green algae. Like most Goodeid-species, Allotoca diazi prefers depths of less than 1m.

Colouration: 

  The fish are cryptically coloured. Meek described the colouration as "light olivaceous, much mottled with darker, which forms irregular cross bars on the sides; many of the larger specimens in life with a reddish tinge over the body, which fades to nearly a uniform light olive; fins all plain. The males are a little duller and of a more uniform colour than are the females." Concerning Zoogoneticus miniatus (the same species; Meek described it in the same paper immediately after diazi), he wrote: "Olivaceous, much mottled with darker. No distinct lateral band. The last blotch forms an indistinct black caudal spot." Nevertheless, the black bars and black spots in the midline between them form an indistinct lateral band. The belly is not spotted, the dorsal part of the body speckled.

Biology: 

  Allotoca diazi is a bottom dwelling species that lives in and near dense beds of vegetation near the shore.

 

  G. Mendoza studied in 1962 on ovaries of three species from the Pátzcuaro lake, including Allotoca diazi. Following his results, diazi has got a gestation-length of 60 - 75 days. He found young continuosly from April to January (extending over 8 or 9 months), so this could happen by a single brood with females starting at different times or by multiple cycles. The average brood size has been 39.9 young per ovary with Embryos nearly the same size. Runts comprised only 0.49%. He believed that diazi matures in the first year.

 

  One female of 75mm SL collected in May 1901 (Meek) contained 28 young, each about 15mm(!) long. Another female of about 80mm contained 47 young, each one about 10mm in length.

Diet: 

  The Pátzcuaro Allotoca is primarily carnivorous and catches insects at the water surface and accepts worms at bait (Kingston, 1979). The gut is short, about as long as the body, the teeth are very large and conical and the mouth is rather large and protractile. This all are indications of a carnivorous nourishment, maybe including small fish.

Remarks: 

  Meek's record from "Chalco, Valley de México" (1902, as Zoogoneticus miniatus) is regarded as an error for another locality of the same name near La Palma, Michoacán (Álvarez del Villar and Narrasco, 1957). It has been described after a small female of 40mm (about 1.6 inches) "closely resembling Skiffia lermae (in the description Skiffia variegata, a synonym) in general colour and form."

 

  Fernando de Buen classified in 1942 the three related species (catarinae, diazi and meeki) as subspecies of diazi. Till today, it isn't cleared in detail, if these three species are really valid, but according to some differences between them and their slightly distinct distribution pattern, it is mostly accepted today. But last studies by Omar Domínguez revealed that the three forms are phylogenetically definitely very close to each other and might belong to one species..

 

  This species can be found together with another AllotocaAllotoca dugesii.

Husbandry: 

   Looking on the biotopes of Allotoca diazi, they suggest 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: 
(Meek, 1902)