Subterranean Fishes of the World

Country

Systematics

There are nine known and named taxa in the Family Amblyopsidae. Of these six are subterranean fishes with the usual troglomorphic characters of reduced eyes and pigment and permanent subterranean existence, and three are epigean fishes with normal eyes and pigment. Recent molecular and morphological evidence produced by Hart et al. (2020) demonstrates that the relationship between these hypogean and epigean fishes is not simple. There are four major clades within the Family:

1. Typhlichthys subterraneus and Typhlichthys eigenmanni are sister species and sister to this pair is Speoplatyrhinus poulsoni.  However, T. subterraneus is quite clearly divided into two subgroups, one of which is closer to T. eigenmanni than it is to the other group of T. subterraneus. The only way to read the cladogram for this group is that it consists of three taxa, one of which is currently un-named. This clade are all subterranean fishes.

2. Two of the epigean fishes, Forbesichthys papilliferus and Forbesichthys agassizii, are sister to each other and their sister is the hypogean species Amblyopsis spelaea.

The two remaining clades contain one species each but their relationships to the other six species is ambiguous:

3a. Sister to the above groups is epigean Chologaster cornuta with hypogean Troglichthys rosae sister to all other taxa.

3b. Sister to the above groups is hypogean Troglichthys rosae with epigean Chologaster cornuta sister to all other taxa.

Given the fact that the distribution of Chologaster cornuta is very far from the distributions of the other taxa 3b seems the most parsimonious explanation. Amblyopsis hoosieri is not included in the paper of Hart et al. (in press) but one would expect it to be in group 2 above based on geography.

This analysis does not take into account the ten possible cryptic taxa, currently subsumed within Typhlichthys subterraneus, identified by Graening, Fenolio and Slay (2011), Niemiller et al. (2013) and Hart, Burress and Armbruster (2016).