Xenotaenia resolanae

Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Xenotaenia resolanae
Original Description: 

  TURNER, C. L. (1946): A contribution to the Taxonomy and Zoogeography of the Goodeid Fishes. Occasional Papers of the Museum of Zoology University Michigan No. 495: pp 1-15

Etymology: 

  The species is named after the type-locality, the Río Resolana in Jalisco.

Holotype: 

  Collection-number: University of Michigan Museum of Zoology, Cat. No. UMMZ-143024.

  The Holotype is a mature female of 34mm SL, collected by B. C. Turner, 29.03.1939.

English Name: 
Leopard Splitfin
Mexican Name: 
Mexclapique leopardo
Synonyms: 

  none

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 Xenotaenia resolanae, following Uyeno, Miller & Fitzsimons, 1983:

2n = 48    48stt  

Size: 
The maximum known SL is 76mm (Miller et al, 2005).
Terra typica: 

  The Holotype comes from a tributary to the Río Purificación, the Río Resolana, about 25 miles SW of the town of Autlan in Jalisco.

Status after IUCN: 

not mentioned

Status following other sources: 

  Vulnerable; Comment: Stable since 2000

Distribution and ESU's: 

  This species comes from the Pacific Slope, from the basins of riós Cuitzmala, Purificación and  Chacala (= Cihuatlán or Marabasco), in the states of Jalisco and Colima.

Habitat: 

  Xenotaenia resolanae can be typically found in pools of clear to turbid streams, over substrates of silt, mud, sand, rocks, leaves and bedrock or boulders. Except  green and brown algae and Potamogeton, Eichhornia and Ceratophyllum, there can be usually found no aquatic-vegetation. The currents are none to slight or moderate. It prefers depths less than 1m, typically not under 0.5m. The temperature in March and April 1975 had been between 22.8 and 25.6°C. Miller described a habitat of this species shadowed by trees.

Colouration: 

  The ground-colour is greenish-vellow, the dorsal part more greenish, the venter yellow. In younger specimens the posterior halves of the scales are darkened by brown and black pigment cells above the lateral line for the entire length of the body and in the belly region for some distance. Along the lateral line there are about 15 irregular patches. In older specimens, these dark patches often become broken up or disappear, whereas the markings upon the individual scales dorsal to the lateral line become more conspicuous. The posterior edges of the scales on the upper part of the body have a metallic glimmer. There are 3 irregular, vertical brownish bars on the caudal fin with many whitish dots between them . The posterior margin of the dorsal fin is edged sparsely with light brown and the tips of the pelvic fins are white. Pectoral fins and anal fin are clear.

Biology: 

  Miller caught young fish in March and April (1975), 13 and 14mm long. In captivity, it produces every month except August and December (Kingston 1979), suggesting a long reproductive period.

Diet: 

  The gut is relatively short (0.85% of the total length) and the teeth, as well as the jaws are very strong. The anterior row is bifid. The gut suggests a carnivorous feeding habit, the teeth might be an indication for omnivorous feeding habits, however with prefering small invertebrates.

Remarks: 

  Turner noted, that the head is unusually long in proportion to the total length and that the caudal peduncle differs little from the other species in proportion to the length. These facts together indicate, that the body in relation is much shorther than in other species.

 

  Xenotaenia resolanae is closely related to Ilyodon and Allodontichthys species and comprises the western-most distributed representative of Goodeids.

 

  Water pollution is threatening this species, too, and it has disappeared from several main localities in the Río Purificación basin.

 

  I observed several times males slowly spreading one of its striking white ventrals, but never seeing doing this during courtship. But nevertheless it might be used as a way to attract females. Further observations could be interesting in this context. 

Locations