The document analyzes the distribution patterns of freshwater fish species in the Chacoan Sub-region of South America using panbiogeography. 38 generalized tracks and 4 nodes were identified for families of Characiforms, Siluriforms, Gymnotiforms and Cyprinodontiforms. The fish distribution patterns matched previously described patterns (A, B, C) found in other taxa, suggesting congruent biogeographic histories among groups in the region.

1. Distributional Pattern of Ichthyofauna in
Chacoan Sub-region, Neotropical Region
(sensu Morrone, 2014)
Corrêa V.A., Figueiredo F.J.1 and Gallo, V.2
1 – Laboratório de Ictiologia, Universidade do Estado do Rio de Janeiro;
2 – Laboratório de Sistemática e Biogeografia de Peixes, Universidade do Estado do Rio
de Janeiro.

2. Introduction
 Geographically, the greatest diversity of freshwater bony fish occurs in the Neotropical Region
(HELFMAN et al., 2009).
 Studies about its origin and history of ichthyofauna are scarce. The recognized biogeographic
patterns of freshwater fish are used only to complement patterns found in terrestrial taxa or are
used to generate models to explain global biogeographic patterns (ALBERT & REIS, 2011)..
 Although the history of neotropical rivers and lakes is recent from the geochronological point of
view, they have unique biotic complexities, which include an outstanding ichthyological diversity
(ALBERT & REIS, 2011).
 In order to reconstruct and understand the history of isolation, divergence and diversification of
ichthyofauna, was used a tool of Historical Biogeography called Panbiogeography.
 This method emphasizes the geographic spatial dimension of biodiversity, allowing a better
understanding of evolutionary patterns and processes (CRAW et al., 1999; MORRONE, 2004,
2009). Using this method is possible to relate the geological history of a region to the distribution
of specific or supraspecific taxa today.
 The objective of this study was recognize distributional patterns of freshwater bony fish from
Chacoan Sub-region.

3. Materials and Methods
 Species of bony fishes was selected from a intersection of
Hydrological Region Maps (ANA, 2015) and the Catálogo das
Espécies de Peixes de Água Doce do Brasil (BUCKUP &
MENEZES, 2007).
 The geographic coordinates of the chosen species was
downloaded from two mainly plataforms: GBIF and SpeciesLink.
 To run the track analysis was used the app Martitracks. The
parameters chosen to analysis was: c = 2; r = 2.5
(lmin)/3(lmax)/4(lmaxline); m=0.8 (minSI).
 There are three important basic concepts in Panbiogeographical
Track Analysis: Individual Track (IT); Generalized Track (GT) and
Panbiogeographical Node (PN).. The results was given in
generalized tracks and nodes.
 The maps was elaborated with QGis. The Neotropical Region map
used was the one availabled by Löwenberg-Neto (2014).

4. Results
 After of the analysis, 38 generalized tracks and 4
nodes was built to families and subfamilies of
Characiforms, Siluriforms, Gymnotiforms and
Cyprinodontiforms. Some of them are shown
bellow:
Crenuchidae GTs 6, 7, 7-8, 7-9, 9 Characinae GTs 11 e 12; 1 PN (N1)
Trichomycteridae
GTs 17, 18, 19, 20, 21
Callichthyidae GTs 22, 23, 24;PN (N2)Gymnotidae – GT34 Rivulidae GTs 35, 36, 37, 37’

5. Discussion
 The biogeographical patterns was corroborated by others taxa. For the families and subfamilies cited
here, was found::
 Patterns of Rivulidae was corroborated by patterns of spiders Mygalomorphae (FERRETTI et al., 2012);
 Patterns of Gymnotidae, Rivulidae, Crenuchidae, Trichomycteridae was confirmed by patterns of Piper (QUIJANO-
ABRIL et al., 2006);
 Patterns of Crenuchidae, Trichomycteridae, Gymnotidae and Rivulidae are congruent with patterns of Cecropia
(FRANCO & BERG, 1997);
 Patterns of Characinae, Crenuchidae, Callichthyidae,Trichomycteridae, Gymnotidae, Rivulidae are congruent with
patterns Cyrtoneurina, Cyrtoneuropsis e Bithoracochaeta (CARVALHO et al., 2003)
 The patterns found can be included in the biogeographic patterns (A, B and C) of Ribeiro (2006). For example:
 A Pattern (old taxa with a few species and a narrow geograohic distribution) – Crenuchidae, Trichomycteridae,
Gymnotidae and Rivulidae;
 B Pattern (sisters taxa in the coastal drainages and crystalline shield) - Trichomycteridae, Callichthyidae.
 C Pattern (result from vacariants events recents) - Callichthyidae e Characinae
 Conclusion: Through track analysis it was possible to identify patterns of distribution of ichthyofauna in
the Chaco Sub-region correspond the patterns A, B and C already described in the literature. The patterns
found for the ichthyofauna are corroborated by others taxa with different dispersion capacities, but which
may have something in common when comparing their histories.