Girardinichthys ireneae

Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Hubbsina turneri
Original Description: 

  RADDA, A. C. & M. K. MEYER (2003): Description of Girardinichthys ireneae sp. n. from Zacapu, Michoacan, Mexico with remarks on the genera Girardinichthys BLEEKER, 1860 and Hubbsina DE BUEN, 1941 (Goodeidae, Pisces). Annalen des Naturhisorischen Museums in Wien (104B): pp 5 - 9

Etymology: 

  This species is named in honor of Mrs. Irene Radda, the wife of one of the describers.

Holotype: 

  Collection-number: Naturhistorisches Museum Wien, Cat. No. NMW-94578.

  The Holotype is a mature male of 22mm SL, collected by A. C. Radda and S. M. Calderon, 14.02.2001.

English Name: 
Zacapu Splitfin
Mexican Name: 
Mexclapique de Lago de Zacapu
Synonyms: 

Hubbsina turneri   de Buen, 1941 (partially)?

Girardinichthys turneri   Radda, 1984 (partially)

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 Girardinichthys ireneae, following Uyeno, Miller & Fitzsimons, 1983:

2n = 48    48 stt  

Size: 
The maximum known SL is 58mm.
Terra typica: 

The Holotype comes from the north end of the Lago (also named Laguna) de Zacapu in Michoacán.

Status after IUCN: 

  not mentioned (included in Hubbsina turneri, means Critically endangered)

Status following other sources: 

  Synonymized with Hubbsina turneri

Distribution and ESU's: 

  This species is restricted to the exorheic Laguna (or Lago) de Zacapu and its outlet in the northeast, the Río Angulo, about 30 - 35km NE of the town of Zacapu in Michoacán.

Habitat: 

The Laguna de Zacapu is a spring-fed lake, drained by the Río Angulo, which divides in two streams after 20km. The habitat at the collection point is 0.5 to 1m deep and the ground is predominantly of mud which leads to a translucent (greenish) to turbid water. The Zacapu Splitfin prefers well planted areas, where it is hiding under the aquatic vegetation, including Chara, Potamogeton, Ceratophyllum and green algae. The water contains a bit of sulphur.

Colouration: 

Radda and Meyer wrote in their (regrettfully extremly short) original description about the colouration simply: "Males of G. ireneae sp.n. (as well as females) have numerous dark spots on body and dorsal fin."

This species appears golden-brown to yellowish-brown with several irregular and different-sized blotches in both sexes. The caudal peduncle, the posterior part of the venter and the base of the dorsal fin are more prominent spotted. Some individuals show a line of blotches on the base of the dorsal fin. The lower side of the head and the anterior part of the venter are coloured golden, yellow or creme without blotches. The dorsal part appears brighter than the ventral part with smaller blotches and spots, more dusky than dark. The fins are clear with some dark speckles.

Biology: 

Brian Kabbes documented a territorial behaviour of this species (1999). He caught a conspicuous male and released it again at an other place. After some time, it was back again. He tried this several times with the same fish, and it came back again each time.

 

J.K. Langhammer (1991) anticipates a nocturnal or crepuscular behaviour, derived from personal observations in captivity and from observations of collectors in the wild. 

 

Diet: 

The teeth have not been examined in the original description, but this species feeds in captivity nearly exclusively from small micro-crustaceans, like Cyclops and Daphnia. Together with its hiding mode of life and a diurnal migration of planctonic invertebrates in lakes ans ponds, it seems that Hubbsina-species are food specialists, picking up small plantonic organisms over the ground.

Remarks: 

The Zacapu-lagoon had been once a large cienega (33 500ha), but has been drained to provide land for cultivation. It is now a small waterbody with only 33.5ha in size. It posseses a rich aquatic vegetation (more than a dozen abundant plants and some more species), the distribution pattern of these plants has importance for the Zacapu fish fauna, which includes besides this Hubbsina six more Goodeid species and a few from other families including some exotics like the common carp.

 

Some scientists don't treat this species as valid (Doadrio, Dominguez), though there are some (but few and weak) differences in the number of fin rays and scales. However, according to molecular and taxonomic studies (Moncayo-Estrada 1993, Doadrio & Dominguez 2004), the species turneri and ireneae are not distinguishable (after Herrejón et al). Domínguez (pers. comitt. 2011) pointed at the fact, that the description of both Hubbsina species had been done with only very few specimens and that the differences between both species might be not enough to separate them from each other. Until we have more facts, we will treat them separatly.

 

There is no report about Hubbsina turneri since 1980, so it seems, most of the observations and breeding reports about Hubbsina turneri have to be referred to Hubbsina ireneae. Hubbsina turneri is likely unknown to the hobby and the science.

 

J.K. Langhammer (1999) indicated that Hubbsina ireneae (like all authors till 2003, he believed it is turneri) differs from other Goodeids in its nocturnal behaviour: "By day it disappears into 'caves' of coconut shells and flower pots of the type used by dwarf cichlids". Possibly correlated with this behaviour is the pale back and dark venter, the reverse of colouration in other, usually diurnal, Goodeids, he stated. Langhammer also posted that "Miller collected significant numbers in deep and very turbid water, similar to Derek and Pat Lambert, who found their best collections occured after heavy rains and on overcast days." Derek Lambert said, following Langhammer again, "that the only time, he has had luck on bright days was by collecting in well-shaded areas away from open water." All of these successful collections happened under conditions simulating dusk or darkness. D. Isla and J. Mangan caught this species in1993 by laying a fish-trap over night on a muddy and dense-planted place. The next day, they had about 50 specimens. This indicates the same nocturnal behaviour, Langhammer described. Again Domínguez (pers. comm. 2010) confirms these observations and believes in a nocturnal behaviour, too.