The Proto-Berbice, an Ancient River that Influences the Modern Distributions and Conservation Challenges of Freshwater Fishes throughout the Western Guiana Shield Jonathan W. Armbruster, Auburn University Nathan Lujan, University of Toronto Lesley de Souza, Field Museum of Natural History
1998 Potaro River Survey Armbruster, J. Knouft, L. Page, M. Hardman, M. Sabaj, photo by Randy Olsebn
Guyana Shield Fishes Unique ecologies Evolutionary Museum? Isolated from other Highlands Most similar to Brazilian Shield Some links to Andes
Guyana Shield Fishes Shield fauna Broken into relatively distinct west and east shield by Essequibo R./Takutu River As Well as North and South Faunas of these quadrants pretty distinct, but borders are porous, particularly in the east
Guyana Shield Fishes Two Portals areas where faunas can cross Can be understood because the Amazon is in a process of parasitizing neighboring basins Casiquiare Connects Orinoco and Amazon Rupununi Savannah connects Amazon and Essequibo (seasonable)
Guyana Shield Fishes In addition, easy to move along the coast in two regions, the Orinoco Delta, and the coast east of the Essequibo Despite Interdigitating in Venezuela, there seems to be little exchange between the Caroni and Cuyuni Possibly easy movement along southern shield Possible Dispersal Between Shields
Guiana Endemism Generally Guiana Shield fishes are different than Amazonian or Andean fishes Particularly in fastwater Shields were prominent early upland habitat Fishes migrated to Andes when they arose and differentiated Some may have migrated back derived Chaetostoma In Guiana Shield
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Takutu Graben Paleolake Maracanta RP Rupununi Takutu Branco
Takutu Graben Paleoake Maracanta RP Rupununi Takutu Branco Lake Amuku
The Proto- Berbice A drainage that once drained much of the Western Guiana Shield
Most of Cenozoic
Pliocene Branco steals Uraricoera and Cotinga (~5 MYA)?
Pleistocene Then Loses Ireng and Takutu (~2 MYA)
Pleistocene Then Modern Arrangement (~2 MYA)
Future The Rupununi Will be Captured
= permanent/seasonal connections = Western Atlantic connection = Eastern Atlantic connection = Southern Guyana Shield connection = Northern Brazilian Shield connection = Caroni-Cuyuni connection = Caroni-Mazaruni connection Casiquiare Canal Rupununi Savanna
Hydrologic History Cladogram Upper Orinoco Upper Negro Lower Orinoco Essequibo Shield Branco Headwaters Atlantic Coast Lower Amazon Casiquiare Canal Capture of the Caura and Caroni by lower Orinoco Loss of proto- Berbice tributaries to Branco Radiation via Amazon FW Loss of proto- plume Berbice headwaters to Orinoco tribs Purus Arch
Peckoltia cavatica lujani capituata otali wernekei braueri lineola vittata compta
Peckoltia sabaji X X X X X
Lithoxus and Exastilithoxus
Pseudancistrus, Pseudancistrus, Guyanancistrus, Lithoxancistrus
Lowland faunal distributions: Leporinus brunneus Proto-Berbice distribution supported by 15 other spp., three distribution types: I-upper-Orinoco and Caura II-plus Cuchivero III-plus Apure Chernoff et al, 1991
Chernoff et al, 1991 15 spp. Characiformes Poecilocharax weitzmani Creagrutus phasma Creagrutus maxillaris Jupiaba polylepis Astyanax scintillans Gnathodolus bidens Pseudanos gracilis Microschemobrycon callops Microschemobrycon casiquiare Anostomus ternetzi Leporinus brunneus Siluriformes Scorpiodoras heckelii Haemomaster venezuelae Ancistrus macrophthalmus Trachydoras microstomus Gymnotiformes Hypopygus neblinae Proto- Orinoco Proto- Berbice NE Atlantic Coast Upper Orinoco Upper Negro Lower Orinoco Essequibo Shield Branco Headwaters Atlantic Coast Lower Amazon Casiquiare Canal Capture of the Caura and Caroni by lower Orinoco Loss of proto- Berbice tributaries to Branco Purus Arch Radiation via Amazon FW Loss of proto- plume Berbice headwaters to Orinoco tribs Hydrologic History Cladogram
Willis et al, 2007 Lowland faunal distributions: Cichla monoculus, C. ocellaris
Willis et al, 2007 Cichla monoculus Cichla ocellaris Proto- Orinoco Proto- Berbice NE Atlantic Coast Upper Orinoco Upper Negro Lower Orinoco Essequibo Shield Branco Headwaters Atlantic Coast Lower Amazon Casiquiar e Canal Capture of the Caura and Caroni by lower Orinoco Loss of proto- Berbice tributaries to Branco Purus Arch Radiation via Amazon FW Loss of proto- plume Berbice headwaters to Orinoco tribs Hydrologic History Cladogram
Hrbek & Taphorn, 2008 Lowland faunal distributions: Rivulidae
Hrbek & Taphorn, 2008 Rivulidae Proto- Orinoco Proto- Berbice NE Atlantic Coast Upper Orinoco Upper Negro Lower Orinoco Essequibo Shield Branco Headwaters Atlantic Coast Lower Amazon Casiquiare Canal Capture of the Caura and Caroni by lower Orinoco Loss of proto- Berbice tributaries to Branco Purus Arch Radiation via Amazon FW Loss of proto- plume Berbice headwaters to Orinoco tribs Hydrologic History Cladogram
Rodriguez & Pereira, 1992 Lowland faunal distributions: Fredius spp.
Rodriguez & Pereira, 1992 Fredius Proto- Orinoco Proto- Berbice NE Atlantic Coast Upper Orinoco Upper Negro Lower Orinoco Essequibo Shield Branco Headwaters Atlantic Coast Lower Amazon Casiquiare Canal Capture of the Caura and Caroni by lower Orinoco Loss of proto- Berbice tributaries to Branco Purus Arch Radiation via Amazon FW Loss of proto- plume Berbice headwaters to Orinoco tribs Hydrologic History Cladogram
Biogeography: Chaetostoma vasquezi and C. jegui C. vasquezi C. jegui Only two species of Chaetostoma known from east of the Andes >40 Andean species disjunct distribution across Shield? Py-Daniel, 1991; Lasso &Provenzano, 1997
Biogeography: Geophagus and Guianacara Geo. grammapareius Geo. taeniopareius Gui. stergiosi Gui. cuyunii two geophagine cichlids with similarly disjunct ranges between upper Caura and Paragua Kullander et al., 1992; López-Fernandez et al., 2006
Faults Transcurrent or major faults Loczy, 1973
Biogeography: Geophagus and Guianacara Geo. grammapareius Geo. taeniopareius Gui. stergiosi Gui. cuyunii two geophagine cichlids with similarly disjunct ranges between upper Caura and Paragua Kullander et al., 1992; López-Fernandez et al., 2006
Biogeography: Harttia merevari Caura: Ventuari: disjunct range of Harttia merevari on western side of Guyana Shield, far from other Harttia spp. Provenzano et al., 2005
But can the Proto-Berbice Predict Distributions? Went to the Ireng in January with some predicted species Harttia and Neblinichthys
Orinduik
Falls of the Surama
Biogeography: Harttia merevari Caura: Ventuari: disjunct range of Harttia merevari on western side of Guyana Shield, far from other Harttia spp.? Provenzano et al., 2005
Biogeography: Neblinichthys
Biogeography: Neblinichthys
Biogeography: Characidium declivirostre group
Biogeography: Trichomycterus
Amaila Falls
Biogeography: Neblinichthys
Falls of the Surama