Meek described the genus Thorichthys with T. ellioti as type species in 1904. Heros maculipinnis Steindachner, 1864 was subsequently considered as a synonym to T. ellioti (e.g. Stawikowski & Werner, 1998; Kullander, 2003), although it is the older available name and would therefore have priority (Artigas Azas, 1996). The actual problem has several layers:
- It seems to be not clear if T. maculipinnis is indeed identical with T. ellioti. Miller (2005) for example considers T. maculipinnis to be a synonym of T. helleri rather than T. ellioti. Although it has been speculated that T. maculipinnis is identical with T. ellioti (e.g. Stawikowski & Werner, 1998; Kullander, 2003), nobody actually provided according data (except for the proximity of the type localities). Has noone ever compared the type specimens? Artigas Azas (1996), well knowing the fish fauna of the Papaloapan, points out that despite the Rio Jamapa (type locality of T. maculipinnis) is not a direct affluent of the Papaloapan (type locality of T. ellioti), the Thorichthys forms in these rivers seem not to be different. However, depending on the species concept, the fact that the Thorichthys from the Rio Jamapa may be isolated from the forms in the Papaloapan system can justify the maintenance of both taxa as valid species.
- Given that T. maculipinnis and T. ellioti are indeed the same species, T. maculipinnis has priority because it is the oldest available name.T. ellioti would be a junior synonym.
- Given that T. maculipinnis and T. ellioti are indeed the same species, T. ellioti, however, may be in prevailing usage (Kullander, 2003).
Thus, to definitely decide on the valid use of the proposed names, the type material has to be compared in order to support the synonymy of the two taxa. Pending such a revision, T. ellioti is used in this checklist according to recent publications (e.g. Stawikowski & Werner, 1998; Kullander, 2003; Miller, 2005).
Thorichthys maculipinnis male from Rio la Antigüa, Veracruz, México, in the aquarium of Rusty Wessel, Louisville. Photo by Spencer Jack.