Jonathan W. Armbruster, Auburn University Nathan Lujan, University of Toronto Lesley de Souza, Field Museum of Natural History

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1 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

2 1998 Potaro River Survey Armbruster, J. Knouft, L. Page, M. Hardman, M. Sabaj, photo by Randy Olsebn

3 Guyana Shield Fishes Unique ecologies Evolutionary Museum? Isolated from other Highlands Most similar to Brazilian Shield Some links to Andes

4 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

5 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)

6 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

7 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

8 Collections

9 Takutu Graben Paleolake Maracanta RP Rupununi Takutu Branco

10 Takutu Graben Paleoake Maracanta RP Rupununi Takutu Branco Lake Amuku

11 The Proto- Berbice A drainage that once drained much of the Western Guiana Shield

12 Most of Cenozoic

13 Pliocene Branco steals Uraricoera and Cotinga (~5 MYA)?

14 Pleistocene Then Loses Ireng and Takutu (~2 MYA)

15 Pleistocene Then Modern Arrangement (~2 MYA)

16 Future The Rupununi Will be Captured

17 = 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

18 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

19 Peckoltia cavatica lujani capituata otali wernekei braueri lineola vittata compta

20 Peckoltia sabaji X X X X X

21 Lithoxus and Exastilithoxus

22 Pseudancistrus, Pseudancistrus, Guyanancistrus, Lithoxancistrus

23 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

24 Chernoff et al, 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

25 Willis et al, 2007 Lowland faunal distributions: Cichla monoculus, C. ocellaris

26 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

27 Hrbek & Taphorn, 2008 Lowland faunal distributions: Rivulidae

28 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

29 Rodriguez & Pereira, 1992 Lowland faunal distributions: Fredius spp.

30 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

31 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

32 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

33 Faults Transcurrent or major faults Loczy, 1973

34 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

35 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

36 But can the Proto-Berbice Predict Distributions? Went to the Ireng in January with some predicted species Harttia and Neblinichthys

37 Orinduik

38 Falls of the Surama

39 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

40 Biogeography: Neblinichthys

41 Biogeography: Neblinichthys

42 Biogeography: Characidium declivirostre group

43 Biogeography: Trichomycterus

44 Amaila Falls

45 Biogeography: Neblinichthys

46 Falls of the Surama