Subterranean Fishes of the World

Country

Types

Holotype: CAC-CDMB (unnumbered)  22.5mm SL

Paratypes: ANSP 187498 45.5 mm SL, CAC-CDMB 88 55.9 mm SL, IAvH-P 10806 52.2 and 57.0 mm SL, UIS-T 1698 49 mm SL, UIS-T 1699 43.5mm SL

Distribution

Type locality: Cueva El Misterio, Acuarela road 3.5 km, Verde Mesa de Los Santos, Municipio de Los Santos, upper Sogamosa River basin, Departamento de Santander, Colombia, elevation 1600 meters. 6°50'21"N, 73°05'18"W. Also known from Petroglifos Cave and Acuarela Cave, Sogamosos drainage, Piedecuesta (Florez et al. 2020).

Habitat

The cave, with a total of 110 m of explored passages, is isolated from the epigean stream and is oriented longitudinally with galleries formed by gentle slope tunnels and narrow passageways. The cave has small wells interconnected by reduced descending channels where water infiltration was observed. In dry months, an isolated sump pool was observed at each gallery. The bottom of each well is rocky and contains much sediment composed chiefly of bat excrement. Cydnid bugs (Hemiptera: Heteroptera) were found inside the wells. Diptera, crayfish  and bats were observed in the interior of the galleries. Water temperature, when the holotype was collected, was 20°C and cave temperature was 18.5°C.

Systematics

Of the species of Trichomycterus found in Colombia Trichomycterus uisae is most similar to Trichomycterus straminius (Castellanos-Morales 2008) but is quite isolated from any other populations of fishes.

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 90 32.1 and 41.1 mm SL, CAC-CDMB 91 45.5mm SL, CAC-CDMB 92 28.3 mm SL, UIS-T 1700, 39.8 mm SL.