Skiffia lermae

Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Skiffia lermae
Original Description: 

  MEEK, S. E. (1902): A contribution to the Ichthyology of Mexico. Publication. Field Columbian Museum. No 65, Zoological Series 3 (6): pp 63 - 128

Etymology: 

  The species is probably named for the basin of the Río Lerma, where the Lago de Pátzcuaro belongs to, the location, where this species has been discovered.

Holotype: 

  Collection-number: Field Columbian Museum, Cat. No. FCM-3616.

  The Holotype has got 54.1mm standard length, collected by S. E. Meek and F. E. Lutz, from 19. to 21.05.1901.

English Name: 
Olive Skiffia
Mexican Name: 
Tiro olivo
Synonyms: 

Skiffia variegata   Meek, 1902

Goodea lermae   Regan, 1907

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 Skiffia lermae, following Uyeno, Miller & Fitzsimons, 1983:

2n = 26    22M/ 4t  

Size: 
The maximum known SL is 64mm (Miller et al, 2005).
Terra typica: 

  The Holotype comes from the Lago de Pátzcuaro in Michoacán.

Status after IUCN: 

  not assessed

Status following other sources: 

  Status: Endangered

  Population development: Some decline since 2000

Distribution and ESU's: 

  This species comes from the Pacific Slope and inhabits the basin of the middle Río Lerma, including the ríos Laja, San Juan, Angulo (including the Lago de Zacapu) and Turbio. Additionally, it inhabits the endorheic basins of the Río Grande de Morelia (including the Lago de Cuitzeo) and lagos Pátzcuaro and Zirahuén in the states of Guanajuato and 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 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 Skiffia lermae, we have the possibility to distinguish three ESU's: The first unit Skile1 encompasses populations from the middle Río Lerma, including fish from the Lago de Zacapu, Río Turbio, Río Laja, Río San Juan, Lago de Yuriria and Río Angula. The second ESU - Skile2 - is used for fish from the endorheic Río Grande de Morelia basin, including the Lago de Cuitzeo and several springs like La Mintzita, La Maiza and San Cristobal. ESU number three, Skile3, is in use for the populations from the lakes Pátzcuaro, the type location of the species, and Zirahuén, the type location of the former Skiffia variegata, now a synonym of Skiffia lermae. As it looks like that the latter has to be treated extinct, it is hard to investigate if both really belong to one ESU, so this has to be seen critically.

Habitat: 

  The habitats are quiet waters of lakes, spring-fed ponds, canals and small creeks with clear to turbid water over mud, sand, gravel and decayed organic matter. The vegetation comprises green algae, Eichhornia, Lemna, Scirpus, Salvinia, Nasturtium and Potamogeton. The species prefers usually depths of less than 1m. The currents are none to slow. 

 

Rancho el Molino IRancho el Molino II

 

Rancho el Molino IIIRancho el Molino IV

 

Rancho el Molino VRancho el Molino VI

 

Lago de Pátzcuaro ILago de Pátzcuaro II

 

Lago de Pátzcuaro IIILago de Pátzcuaro IV

 

Manantial La Mintzita IManantial La Mintzita II

 

Manantial La Mintzita IIIManantial La Mintzita IV

 

Laguna Zacapu ILaguna Zacapu II

 

Laguna Zacapu IIILaguna Zacapu IV

Laguna Zacapu V

Laguna Zacapu VI

Colouration: 

The Ground-colour of both sexes is olive. Darker on the dorsal side and brigther on the belly, becoming yellowish to yellow. Females have got several smaller and bigger spots and blotches, giving them a marbled appearance. Males are less marbled, but appear darker than females. A dark vertical stripe on the base of the caudal fin and the ventral part of the caudal peduncle black is often reported. Females may show a dusky lateral band. 

 

Kingston described the colour of males of Skiffia lermae more colourful, with bright orange caudal peduncles and caudal fins and blue-black heads.

 

The Skiffia lermae from Lago de Zacapu is coloured deep yellow without marbles.

 

The variabiliy in this species, like in its congener Skiffia multipunctata seems to be high.

Biology: 

Following Miller, the reproductive period lasts from at least February to May, indicated by newborn young or pregnant females taken then. He also documented this species swimming just beneath the surface in full sunlight, the young often in groups of thre to fifteen. 

Diet: 

The gut is - following Pellegrin - long and often convoluted. It is about 3 times the length of the fish. The teeth are mainly bifid in both rows. This species is mainly grazing aufwuchs, for example from submerged Scirpus stems, and algae. It is also attracted by insects at the surface.

Remarks: 

Meek described in 1902 not only Skiffia lermae from the Pátzcuaro lake, but also Skiffia variegata from the Lago de Zirahuén. Following Meek, it differs from lermae by being more slender and by differences in the colouration. It has been already synonymized by Regan (1906-08), established again by Hubbs & Turner (1939) but finally synonymized by Miller & Fitzsimons in 1971.

 

In the Zacapu-lake lives a yellow population of Skiffia, called Skiffia sp. "Sailfin" or Skiffia sp. "Zacapu". Following O. Domínguez, it differs from lermae not so much, that a separate species has to be described. It is therefore treated as a population of Skiffia lermae.

 

Skiffia lermae differs from multipunctata mainly by its "stretched" caudal peduncle, the smaller dorsal fin, the more slender bodyshape, the smaller size and the colouration, so lermae never shows big black blotches on the sides and is characterized by the typical colouration of the caudal-area in males.

 

In the wild, this species -  like all Skiffia-species, is very rare. Only 4 of the historical 7 reported sites of this species are populated, the biggest populations living in the Laguna Zacapu and the La Mintzita spring in the Lago de Cuitzeo basin.

Locations