There are two species in this
genus, P. phreatophila and P. lundbergi
from the Tamesí River drainage, northeastern
México. Taylor (1955, 1969) suggested that
P. phreatophila is the sister group of of
the large and extensive genus Noturus. Like
many organisms that inhabit caves the Mexican blindcat
possesses no eyes, which is compensated by the development
of other senses. Studies have shown that the Mexican
blindcat has acute hearing and can rapidly perceive
the odour or taste of non-moving food, such as mosquito
larvae. Aggressive encounters between Mexican blindcats
have been observed, during which they bite at one
another and then lock jaws, often remaining in mouth
to mouth contact for many hours. All of the aggressive
individuals appeared to be males; however, the reason
behind this hostile behaviour is not yet fully understood.
Mexican blindcats have also been seen resting motionless
on the substrate, or drifting with currents. This
behaviour would seem to leave this small fish extremely
vulnerable to predation, and thus may reflect the
lack of predators in their natural habitat. Description:
The dorsal fin lacks a spine and the snout overhangs
the mouth. The adipose fin is joined to the caudal
fin without an obvious flap posteriorly. There are
15 caudal rays and 10-14 rakers on the first gill
arch. The edge of the caudal fin is straight. There
are well developed lateral-line canals and pores on
the head. Colouration: The Mexican
Blindcat lacks eyes and is pinkish white. Etymology:
The specific name phreatophila: phréatos,
genitive of phréar, artificial well; phila,
from phílos, fond of, referring to type locality,
a 2.5-m-deep well in Muzquiz, Coahuila, Mexico.
Common
Name:
Mexican blindcat
Synonyms:
None
Family:
Ictaluridae
Distribution:
North America:
Mexico, Caves in Bravo River basin, Coahuila, from
near Múzquiz northward to about 50 km SW of
Ciudad Acuña and to near Allende. Type
locality: Well at base of Sierra de Santa
Rosa, ca. 27º55'N, 101º07'W, Múzquiz,
Coahuila state, Mexico.
Size:
9.0cm. T.L. (3½ins)
Temp:
15-23°C (57-73°F)
p.H.
6.0-7.5.
IUCN
Red List
This
species has a restricted range in subterranean systems
in northern Coahuilla, Mexico, and southern Texas, USA,
which gives an estimated extent of occurrence of 10,500
km2 over 14 known sites. It is thought to be declining
in population and range due to the major threats of
excessive aquifer depletion and pollution. The rate
of population decline is unknown but may be severe,
and some populations may be on the verge of extirpation.
It likely has between 10 to 15 threat-based Locations,
as some sites are probably hydrologically connected
while others are likely undiscovered within its range.
It therefore could fall into a range of Categories from
Near Threatened to Endangered. As a precaution it is
assessed as Vulnerable B1ab(iii), and studies of its
distribution and population trends is urgently needed
alongside site protection and restoration (IUCN 2019).
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