Prietella

Taxobox
name = "Prietella"
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Siluriformes
familia = Ictaluridae
genus = "Prietella"
genus_authority = Carranza, 1954
type_species = "Prietella phreatophila"
type_species_authority = Carranza, 1954
subdivision_ranks = Binomial name
subdivision =
"Prietella lundbergi"
Walsh & Gilbert, 1995
"Prietella phreatophila"
Carranza, 1954

"Prietella" is a small genus of catfishes (order Siluriformes) of the family Ictaluridae. It includes two species, the phantom blindcat, "P. lundbergi", and the Mexican blindcat, "P. phreatophila".cite journal|url=http://silurus.acnatsci.org/ACSI/library/biblios/2007_Ferraris_Catfish_Checklist.pdf|title=Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types|first=Carl J., Jr.|last=Ferraris|journal=Zootaxa|volume=1418|pages=1–628|year=2007|format=PDF] FishBase species|genus=Prietella|species=lundbergi|year=2007|month=July] FishBase species|genus=Prietella|species=phreatophila|year=2007|month=July]

Taxonomy

"Prietella" has been confirmed to be monophyletic and to be the sister group of the "Noturus". The karyotype of "P. phreatophila" is indistinguishable from one of the genus "Noturus"; however, its diploid number of 50 chromosomes differs from the proposed ancestral "Noturus" karyotype of 54–56 chromosomes.cite journal|title=The Karyotype of the Mexican Blindcat, "Prietella phreatophila" Carranza (Ictaluridae)|first=Chris T.|last=Amemiya|coauthors=Kelsch, Steven W.; Hendricks, Fred S.; Gold, John R.|journal=Copeia|year=1986|doi=10.2307/1445307|volume=1986|pages=1024] However, this relationship has not been supported by preliminary mitochondrial DNA sequence data. Despite similarity to other cave-dwelling species of Ictaluridae, they are not closely related.cite journal|title=New Species of Troglobitic Catfish of the Genus "Prietella" (Siluriformes: Ictaluridae) from Northeastern México|first=Stephen J.|last=Walsh|coauthors=Gilbert, Carter R.|journal=Copeia|year=1995|issue=4|pages=850–861|doi=10.2307/1447033|volume=1995]

Distribution and habitat

The distribution of "Prietella" now is known to extend from the very northern part of the state of Coahuila, Mexico, very near the international boundary, to the southernmost Tamaulipas, 750 kilometres (470 mi) away to the southeast.cite journal|title=Mexican blindcats genus "Prietella" (Siluriformes: Ictaluridae): an overview of recent explorations|first=Dean A.|last=Hendrickson|coauthors=Krejca, Jean K.; Martinez, Juan Manuel Rodríguez|journal=Environmental Biology of Fishes|volume=62|pages=315–337|year=2001|doi=10.1023/A:1011808805094] The distribution of "P. lundbergi" is very restricted; "P. lundbergi" is known from two springs of the Tamesí River drainage in the Tamaulipas state of Mexico. "P. phreatophila" has a greater distribution than "P. lundbergi"; "P. phreatophila" originates from the Bravo River basin, Coahuila, from near Múzquiz northward to about 50 km (31 mi) southwest of Ciudad Acuña and to near Allende, Mexico. Both species occupy different Gulf of Mexico drainages and are separated by about 600 km (370 mi).

"P. lundbergi" is a cave-restricted species. "P. phreatophila" occurs in wells. Most "Phreatophila" have been found well in habitats that likely have relatively little short-term fluctuation in environmental parameters. For the most part, they are found in still pools; they have never been seen in shallow running water. Often they are associated with a silt substrate.

Description

Like other cave species of catfish including the ictalurids "Trogloglanis pattersoni" and "Satan eurystomus", "Prietella" species lack pigmentation and eyes and have a reduced lateral line. In "Prietella", the lateral line is more reduced than in other members of the subfamily; after the gill opening, it is reduced to three or fewer pores. "P. lundbergi" differs from "P. phreatophila" by a number of characteristics including a reduced or absent swimbladder, a more emarginate to weakly-forked caudal fin, and a more deeply notched adipose fin. "P. lundbergi" grows to about 4.5 centimetres (1.8 in) SL.

Behavior

Jaw-locking behaviors have been observed in "P. phreatophila". Fish that have been presumed to be males when first coming in contact with each other will engage in this behavior that is thought to establish a social dominance hierarchy. Jaw-locking usually lasts less than 30 minutes but has been recorded to last for many hours. The dominance relationships are long-term; the same two fish usually do not engage in this behavior again.

"P. phreatophila" may lie motionless or drift in the current with their breathing slowed. Though they may be awakened by disturbances, this behavior is likely due to lack of predators in their habitat as this behavior would likely leave them extremely vulnerable to predation.

Relationship to humans

Trade of "P. phreatophila" is restricted in Germany.

Both species of "Prietella" are on the IUCN Red List. "P. lundergi" is a vulnerable species, and "P. phreatophila" is an endangered species.IUCN2006|assessors=World Conservation Monitoring Centre|year=1996|title=Prietella lundbergi|id=18137|downloaded=29 July 2007] IUCN2006|assessors=World Conservation Monitoring Centre|year=1996|title=Prietella phreatophila|id=18136|downloaded=29 July 2007] "P. phreatophila" is threatened by groundwater pollution and overfishing. It has been noted that "P. phreatophila" should be considered a threatened species due to being found in more localities than previously thought and recommended that "P. lundbergi" be considered endangered due to its extreme rarity.

References