Subterranean Fishes of the World

Country

Types

Holotype: CAC-CDMB 035 100.7 mm SL, Paratype: CAC-CDMB 051 78.7 mm SL.

Distribution

Known only from the type locality: Cave El Puente, Portugal Street, municipality of Lebrija, upper Lebrija River basin, Santander, Colombia. (07°09’49’’ N, 073°17’21’’W).

Habitat

The Cave El Puente is located in the center of a mountain to the west of the Andean mountain range in Colombia. The cave is oriented vertically with narrow, rocky passageways and galleries where water infiltration was observed. The wells are small, shallow, blocked by ceilings of rock and interconnected by reduced descending channels that drain the limited water flow. Water temperature during the sampling was 21.5 °C and cave temperature was 19.9 °C. The bottom of the wells is rocky and contains much sediment (only four specimens of T. santanderensis were collected here). Bats and a diversity of arthropods inhabit the interior of the galleries. The cave is located in an area untouched by agrochemical products, where the practice of sustainable agroforestry has maintained the flora and fauna relatively well conserved, and where the Autonomous Regional Corporation for the Defense of the Bucaramanga Plateau is preparing a conservation program (Castellanos-Morales 2005).

Systematics

Trichomycterus stramineus is the most similar to T. santanderensis.

Biological Notes

Florez et al. (2020) made a very thorough study of both epigean and hypogean Trichomycterus in the Province of Santander, Colombia. They were keen to understand whether the hypogean populations were derived from a single colonisation, evolution of troglomorphy and then dispersal to the known cave sites, or whether there had been multiple parallel colonisations followed by independent evolution of troglomorphy. Their data were quite clear that it was the second of these possibilities that had occurred and that some cave populations are very closely related to epigean ones.

Figure 2 of Florez et al. (2020) shows the relationships of all sampled Trichomycterus, and some other, taxa. The best supported clades are numbered 1-3 and hypogean Trichomycterus are found only in clades 1 and 2. Unnumbered clades received lower support and are not relevant here as they contain no troglomorphic taxa. Clade 1 consists of only the troglomorphic T. rosablanca and the widespread epigean species Eremophilus mutisii. Clade 2 is bigger and considerably more complex with 27 terminal taxa in four groups. Group 1 is monophyletic and consists of only the troglomorphic Trichomycterus undescribed species Guapota (3 terminals). Group 2 consists of two taxa, the non-troglomorphic Trichomycterus undescribed species Guadalupe (5 terminals) and the non-troglomorphic T. latistriatus (1 terminal). Group 3 is monophyletic and complex with 18 terminals. Three taxa are found in this group: T. sandavali (4 terminals), Trichomycterus undescribed species Zapatoca (7 terminals) and the hypogean, though apparently not troglomorphic T. uisae (7 terminals). Group 4 is monophyletic and consist of only the non-troglomorphic Trichomycterus undescribed species Curiti (3 terminals). From this set of data we can see that there are at least an additional two troglomorphic species in the genus that are not yet described, Guapota and Zapatoca. This takes the number of troglobitic species in the country to 12 with 5 currently undescribed. However, the lack of genetic structure in Group 3 strongly suggests that all terminals are very closely related and could be considered as the same species. If this were to be accepted then the formal name would be Trichomycterus sandovali Ardila Rodriguez 2006 and Zapoatoca need not be described.

Museum Holdings

As above plus: CAC-CDMB 050 73.4 mm SL, dissected; CAC-CDMB 052 55.5 mm SL, dissected.