The forgotten Thorichthys maculipinnis

Thorichthys maculipinnis male in breeding dress at Otapa river in Veracruz, México. Photo by Ad Konings.

The Papaloapan river or Rio de las Mariposas (river of the butterflies) flows down to the east from the volcanic highlands of the Mexican plateau, originating from cold water springs in these mountains. At first a rapid mountain stream, further downstream the river becomes wider and flows peacefully across a landscape characterized by tropical lowland vegetation, eventually emptying into the Gulf of México at the city of Alvarado, between extremely beautiful salt lagoons. The drainage of the Papaloapan and its smaller tributaries is bordered to the north by a volcano belt 60 kilometers north of Veracruz, the state capital. This belt is the remains of a large volcanic chain that once extended from the central part of the country to the Gulf of México, and meets the sea at Punta del Morro, just south of the 20th parallel north. This mountain chain acts as an effective geographical barrier to the spread of freshwater fishes.