INVESTIGADORES
PEREZ Alejandra patricia
congresos y reuniones científicas
Título:
Distribution and ecology of freshwater ostracods in northern Patagonia: an approach
Autor/es:
COVIAGA, CORINA; CUSMINSKY GABRIELA; PEREZ, A. PATRICIA; DIAZ, ANALIA; ALPERIN, MARTA
Reunión:
Simposio; 17th International Simposium in Ostracoda; 2013
Resumen:
There are only a few studies about the ostracod faunal assemblages and their environmental
requirements from Patagonia (e.g. Cusminsky et al. 2011; Ramón Mercau et al. 2012).
Here we present the results of a survey of thirteen water bodies (streams, springs,
temporary habitats) in Northern Patagonia (39° 52'- 41°50' S; 70°36'- 71°27' W) and
their comparison with those of previous studies in the earstern Patagonia. The goal of this
research is to enhance our understanding of the regional Patagonian ostracoda fauna and
evaluate the relationship between ostracod species and physical and chemical (depth,
temperature, pH, conductivity, dissolved oxygen concentration, seston and main ions)
parameters of host waters along a W-E precipitation gradient (ranging from 1200 to
160mm/annually). To date, seven species were identified: Amphicypris nobilis Sars 1901,
Bradleystrandesia fuscata (Jurine, 1820), Cypridopsis vidua (O. F. Müller, 1776), Cypris
pubera O. F. Müller 1776, Eucypris virens (Jurine, 1820), Heterocypris incongruens
(Ramdohr, 1808) and Tonnacypris lutaria (Koch, 1838). The more frequent species were T.
lutaria and E. virens, while A. nobilis and C. vidua were only found in one site. Males of A.
nobilis were found while the other species were represented only by females. The
environment of this fauna is related to low conductivity and salinity in the water.
Conversely, previous studies in the easternmost area of Patagonia have shown different
fauna such us Penthesinelula incae (Delachaux, 1928), Potamocypris smaradigma (Vávra,
1891), Ilyocypris ramirezi Cusminsky and Whatley, 1996, Limnocythere patagonica
Cusminsky and Whatley, 1996, Eucypris fontana (Graf, 1931), Kapcypridopsis megapodus
Cusminsky et al. 2005 and Limnocythere rionegroensis, Cusminsky and Whatley, 1996
living in comparatively higher conductivity (Cusminsky et al. 2011). The latter suggest that
the decreasing precipitation trend towards eastern Patagonia is reflected in the distribution
of different ostracod fauna association. On the other hand, new distributions of
cosmopolitan species are present, spreading out their geographical distribution to the
Neotropical region (Martens et al. 2008). Some of the species such us C. pubera, E. virens
and B. fuscata have been also described in the Neartic region, suggesting that birds could
be responsible to their dispersion. However, the mode of dispersion of T. lutaria in this
region is still an open question.