A new inventory for fishes of headwater streams from the rio das Cinzas and rio Itararé basins, rio Paranapanema system, Paraná, Brazil

Abstract: The rio das Cinzas and rio Itararé basins are important tributaries of the rio Paranapanema, a major left-bank tributary of the upper rio Paraná basin. The upper reaches of both drainages intersect the northern portion of the APA Escarpa Devoniana (Devonian Escarpment Environment Protection Area, EPA), an area considered crucial for the preservation of biodiversity. This study aimed to provide an ichthyofaunistic inventory for headwater streams of the rio das Cinzas and rio Itararé basins, both within and off of the borders of the EPA, increasing the knowledge about the species already known from streams in the rio Paranapanema system. We found 32 fish species, representing five orders and 12 families. Siluriformes was the richest order followed by Characiformes. Ten species presented high abundance of sampled individuals, contributing with 85.0% of all specimens. Most species were classified as occasional (captured in less than 25% of the samples) and only two species were classified as constant (captured in more than 50% of samples), which may reflect the altitudinal gradient. We did not record any introduced species in the sampled streams, reinforcing the need of, at least, maintaining the original area of the EPA. We expanded the geographic distribution of Astyanax bifasciatus to the upper rio Paraná system, confirming the cases of faunal exchange among several drainage systems in the limits of the Ponta Grossa Arch. Finally, we identified three putatively undescribed species that show a large biodiversity knowledge shortfall for the region studied.

摘要：辛扎斯河（rio das Cinzas）与伊塔雷河（rio Itararé）流域为巴拉那帕内马河（rio Paranapanema）的重要支流，而巴拉那帕内马河是巴拉那河上游流域左岸的主要支流。两条河流的上游汇水区域与德文尼亚斯卡帕崖壁环境保护区（APA Escarpa Devoniana）的北部区域重叠，该区域被视为生物多样性保护的关键区域。本研究旨在为覆盖该环境保护区境内及边界外区域的辛扎斯河与伊塔雷河源头溪流构建鱼类区系名录，以深化对巴拉那帕内马河流域溪流已知物种的认知水平。本次采样共记录32种鱼类，隶属于5目12科。其中鲇形目（Siluriformes）的物种丰富度最高，其次为脂鲤目（Characiformes）。10个物种的采样个体丰度较高，合计占所有采样标本的85.0%。多数物种被归类为偶见种（采样捕获率低于25%），仅2个物种为恒见种（采样捕获率高于50%），这一分布特征可能反映了该区域的海拔梯度效应。本次采样未记录到任何外来物种，进一步印证了至少维持该环境保护区原始面积的必要性。本研究将双带丽脂鲤（Astyanax bifasciatus）的地理分布范围拓展至巴拉那河上游流域，验证了蓬塔格罗萨穹地（Ponta Grossa Arch）边界内多个汇水系统间存在动物区系交流的现象。最后，本次研究发现3个疑似未描述的新物种，凸显了该研究区域仍存在较大的生物多样性认知缺口。