Salvador Contreras Balderas, Universidad Autónoma de Nuevo León. Additional text was modified from Abell et al. (2000).
Major Habitat Type
Tropical and subtropical coastal rivers
Drainages flowing into
Gulf of Mexico
Main rivers to other water bodies
The extent of the ecoregion is defined largely by the watershed of the Río Papaloapan and its tributaries that drain into the Gulf of Mexico. Major tributaries include Río Santo Domingo, Río San Juan, and Río Trinidad. There are also tributaries of the Laguna de Alvarado, including Río Blanco, Río Otopa, and some basins like Laguna Mandinga, Laguna de Catemaco, and Presa Miguel Alemán.
This coastal ecoregion encompasses the Río Papaloapan basin, which covers most of central Veracruz, two disjunct portions of eastern Puebla, and part of northern Oaxaca.
The headwaters of the Papaloapan rise in the Sierra Madre Oriental in the western part of the ecoregion, and then drain towards the Gulf of Mexico. Elevations in the ecoregion range from sea level to over 3000 m asl. Sierra Madre de Oaxaca lies in the southwest and the Eje Volcánico lies at the northern border.
Freshwater habitats include headwaters, springs, creeks, lakes, lagoons, falls, rapids, and pools.
In the northeastern part of the ecoregion is Laguna de Catemaco, a volcanic crater lake 335 m above sea level. A number of small streams flow down the interior face of the crater into the lake, which has an outlet to the northeast into a river known locally as the Río Grande. Twelve kilometers downstream of the outflow, a 45-meter high waterfall, the Salto de Eyiplanta, effectively isolates the lake from the lower reaches of the Río Papaloapan system. The lake is extremely turbid due to suspended particles of basaltic dust.
The ecoregion contains a variety of terrestrial ecoregions, including moist forests, dry forests, and mangroves along the coast and pine-oak forests, dry forests, and matorral at higher elevations.
Description of endemic fishes
The Papaloapan ecoregion is characterized by relatively high endemism within its ichthyofauna. Around 28 percent of the native fish species are endemic to this region. Endemics include the graceful priapella (Priapella bonita), Olmec priapella (P. olmecae), blindwhiskered catfish (Rhamdia reddelli), and species of Atherinella and Xiphophorus. Also within this ecoregion is Laguna de Catemaco, a remarkable lake with endemic fish such as the Catemaco characin (Bramocharax caballeroi).
Justification for delineation
Ecoregion delineations were based on qualitative similarity/dissimilarity assessments of major basins, using the standard administrative hydrographical regions of the Mexican federal government. Although the Papaloapan, Coatzacoalcos, and Usumacinta rivers share genera or lower level species complexes, there are endemic and distinctive species for each basin, like the series of Priapella, Atherinella, Theraps, and Thorichthys. This justified the distinction of each basin as a separate ecoregion.
Level of taxonomic exploration
Poor along the western mountainous headwaters and also around coastal lagoons, but regular within the middle ranges.
- Chernoff, B. (1986). "Systematics of American atherinid fishes of the genus Atherinella. I. The subgenus Atherinella" Proc. Acad. Nat. Sci. Phila. 138 (1) pp. 86 - 188.
- Contreras-Balderas, S., Obregón, H. and Lozano, M. L. (1996). "Punta del Morro, an Interesting barrier for distributional patterns of continental fishes in North and Central Veracruz, México" Acta Biol. Ven. 16 (4) pp. 37-42.
- Hubbs, C. L., Miller, R. R. and Hubbs, L. C. (1974). "Hydrographic history and relict fishes of the North-Central Great Basin" Memoirs of the California Academy of Sciences, vol 7. San Francisco: California Academy of Sciences.
- Obregón-Barbosa, H., Contreras-Balderas, S. and Lozano-Vilano, M. L. (1994). "The fishes of Northern and Central Veracruz, México" Hydrobiologia (Belgium) 286 pp. 79-95.
- Abell, R. A.,Olson, D. M.,Dinerstein, E.,Hurley, P. T.,Diggs, J. T.,Eichbaum, W.,Walters, S.,Wettengel, W.,Allnutt, T.,Loucks, C. J.;Hedao, P. (2000). "Freshwater Ecoregions of North America: A Conservation Assessment" Washington, DC, USA: Island Press.
- Köppen, W. (1936). "Das geographische System der Klimate" Köppen W. and R. Geiger (Ed.) Handbuch der. Klimatologie ( (Vol. 1, pp. 1–44 ) Berlin, Germany: Gebrüder Borntröger.
- Hijmans, R. J., S. Cameron and Parra., J. (2004) \WorldClim, Version 1.4 (release 3). A square kilometer resolution database of global terrestrial surface climate\ "<"[http://www.worldclim.org]">" (16 July 2009)