Briñoccoli YF, Jardim de Quieroz L, Paracampo A, Somoza GM, Montoya-Burgos JI, Cardoso YP

1. GEOGRAPHIC ISOLATION OF Hypostomus cordovae
(SILURIFORMES, LORICARIIDAE) IN ARGENTINA
Briñoccoli YF1, Jardim de Quieroz L2, Paracampo A3, Somoza GM1,
Montoya-Burgos JI2, Cardoso YP4
ybrinoccoli@intech.gov.ar
1Laboratorio de Ictiofisiología y Acuicultura. Instituto Tecnológico Chascomús (CONICET-UNSAM). Chascomús, Buenos Aires, Argentina.
2Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland.
3Instituto de Limnología Dr. Raúl A. Ringuelet. CONICET-CCT La Plata-UNLP. La Plata, Buenos Aires, Argentina.
4Laboratorio de Sistemática y Biología Evolutiva (LASBE), Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata. La Plata,
Buenos Aires, Argentina.

2. INTRODUCTION
HYPOSTOMUS CORDOVAE (GÜNTHER 1880)
• Bottom-dwelling fishes
• Sucker-like mouth and by their body covered with
bony plates
• Endemic of Argentina
• Wide range of environments (present in exorheic
and endorheic basins)
MOST COMMON STRUCTURING PATTERNS
• isolation-by-distance pattern (IBD)
• isolation-by-barrier (IBB)
• isolation-by-environment (IBE)
2
HOW THESE STRUCTURING PATTERNS CAN EXPLAIN POPULATION GENETIC
VARIABILITY IN THIS SPECIES?
During dry periods, some of the rivers in the upper
regions of the South American continent may suffer a
significant decrease in their waters, preventing them
from reaching the rest of the system's water network.
This is the mechanism by which a basin can fragment
into various systems. If the isolation time is prolonged, it
will cause population genetic differentiation within
the species that have been fragmented.

3. MATERIAL AND METHODS
3
▪ 14 localities (EN: 1, 2, 3, 5, 6, 7, 8, 9, 10, 14; EX: 4, 11, 12, 13)
▪ Sequencing of the mitochondrial region control (D-loop)
▪ Phylogeny according to Maximum Likelihood
▪ SAMOVA, AMOVA
▪ Distance-based redundancy analysis (db-RDA):
Response variable: pairwise-FST matrix
Explanatories variables:
1- Geographical distance calculated by considering
the course of the rivers – IBD
2- Type of basin (exorheic and endorheic) - IBB
3- Altitude and latitude - IBE

4. 4
29%
IBD
53%
IBB0%
AIC: -118.9895
p: 0.005
SAMOVA:
K= 4
FCT= 0.5
AMOVA according to SAMOVA
groups:
FCT= 0.5
FST= 0.52
FSC= 0.04 (p non significative)
db-RDA:
RESULTS

5. 5
CONCLUSION
• We identified 6 different haplotypes.
• Altitude and latitude do not explain population genetic variability of H. cordovae.
• Isolation-by-distance (IBD) pattern explained 29% of the variance of the genetic structure, this mean that the
genetic similarity among populations tends to decay when geographical distance increases.
• Isolation-by-barrier (IBB) associated by basin type explained 53% of the variance. Basin fragmentation would
be playing a fundamental role in the diversity due to the low genetic flow between these basins.
These results show that in H. cordovae the process driving population diversification is complex and it is not limited
to a single mechanism.
BIBLIOGRAPHY
Cardoso, Y. P., Brancolini, F., Protogino, L., Paracampo, A., Bogan, S., Posadas, P., & Montoya-Burgos, J. I. (2019). An integrated approach clarifies the cryptic diversity in Hypostomus Lacépède 1803
from the Lower La Plata Basin. Anais da Academia Brasileira de Ciências, 91(2).
Jardim de Queiroz, L., Torrente-Vilara, G., Quilodran, C., da Costa Doria, C. R., & Montoya-Burgos, J. I. (2017). Multifactorial genetic divergence processes drive the onset of speciation in an Amazonian
fish. PLoS ONE, 12(12), e0189349.
Rahel, F. J. (2007). Biogeographic barriers, connectivity and homogenization of freshwater faunas: it’ s a small world after all. Freshwater Biology, 52, 696–710.
Wang, I. J., & Bradburd, G. S. (2014). Isolation by environment. Molecular Ecology, 23(23), 5649–5662.
Wright, S. (1943). Isolation by Distance. Genetics 28: 114–38.