Update on the checklist of fish species of the Bolivian Amazon

Results and Discussion Twenty one fish species not listed in neither Pouilly et al. (2010) nor Carvajal-Vallejos and Zeballos Fernández (2011) have been found to occur in the Bolivian Amazon (Table 1). Of those 21 species, three are reported as new for Bolivia (Apistogramma urteagai Kullander 1986 and Vandellina sanguinea Eigenmann 1917) or have been reported very recently (Hyphessobrycon elachys Weitzman, 1984; see Hablützel, 2012). Corydoras mamore Knaack, 2002, Apistogramma similis Staeck 2003 and A. acrensis Staeck 2003 have been reported in foreign language aquarium hobbyist literature (Knaack 2003; Staeck 2003; Lahrmann 2010). Six species (Hyphessobrycon pando Hein, 2009, Serrasalmus odyssei Hubert and Renno, 2010, Jurengraulis juruensis (Boulenger, 1898), Aphyolebias claudiae Costa, 2003, Nannoptopoma sternoptychum Schaefer, 1996 and Megalonema amaxanthum Lundberg and Dahdul 2008) have apparently been overlooked by other researchers. The remaining nine species inhabit (sub-) mountainous streams of the Andes at more than 250 m altitude, a region which has not been considered in other recent checklists (Pouilly et al. 2010; CarvajalVallejos and Zeballos Fernández 2011). Although only a small fraction of the 21 fish species are new reports for Bolivia, the present brief review on some rarely read literature will further contribute to our knowledge on Bolivian ichthyodiversity and can be regarded as an update on the publications by Pouilly et al. (2010) and Carvajal-Vallejos and Zeballos Fernández (2011). Below, we will shortly discuss questionable or new records as well as records published in journals which may be difficult to obtain. Siluriformes – Trichomycteridae Introduction Bolivia is one of the richest countries of the world when measured in its biodiversity (Ibisch and Mérida 2004). This stands in a stark contrast with the poor taxonomic knowledge of the fish species in the Bolivian Amazon. Although this information is crucial for nature conservation and ecological research, there are serious gaps in our knowledge about the occurrence and distribution of fish taxa in this region. Recently, new checklists of fish species of the Bolivian Amazon has been published (Pouilly et al. 2010; Carvajal-Vallejos and Zeballos Fernández 2011). However, the authors of these faunal surveys missed a substantial amount of species occurring in the study area, indicating the difficulties to compile an overview on the available literature. In this brief review, we will present a list of additional fish taxa occurring in the Bolivian Amazon.


Introduction
Bolivia is one of the richest countries of the world when measured in its biodiversity (Ibisch and Mérida 2004).This stands in a stark contrast with the poor taxonomic knowledge of the fish species in the Bolivian Amazon.Although this information is crucial for nature conservation and ecological research, there are serious gaps in our knowledge about the occurrence and distribution of fish taxa in this region.Recently, new checklists of fish species of the Bolivian Amazon has been published (Pouilly et al. 2010;Carvajal-Vallejos and Zeballos Fernández 2011).However, the authors of these faunal surveys missed a substantial amount of species occurring in the study area, indicating the difficulties to compile an overview on the available literature.In this brief review, we will present a list of additional fish taxa occurring in the Bolivian Amazon.

Materials and Methods
Reports of fish species for the Bolivian Amazon in this study stem from a literature survey including old and German language reports and from re-examinations of fish specimens deposited in the collections of the CIRA-UAB and CBF.Only fish taxa with available names appearing in neither Pouilly et al. (2010) nor Carvajal-Vallejos and Zeballos Fernández (2011) are included in this article.Note that these two studies did not consider species from the Andean portion of the Bolivian Amazon River drainage or from the Acre River drainage.Exotic species and taxa not identified at species level (questionable taxonomic status or new species) were not considered in this study.
Abstract: In 2010 and 2011 new checklists of fish species occurring in the Bolivian Amazon have been published.We add 21 species to these lists of which two are new reports for Bolivia (Apistogramma urteagai Kullander, 1986 andVandellia sanguinea Eigenmann, 1917).The other 19 taxa have been reported earlier for the Bolivian Amazon.Their absence on previous checklists indicate the difficulties to compile an overview of the current literature on the fish fauna of the Bolivian Amazon.The ichthyofauna of Bolivia is still not entirely known and many species await formal descriptions.Future collection efforts and taxonomic reviews might rise the number of known Bolivian fish species considerably in the near future.

Update on the checklist of fish species of the Bolivian Amazon
Hablützel et al. | Fish species of the Bolivian Amazon: Update Vandellia sanguinea Eigenmann 1917 is first reported from Bolivia.The species was identified based on the diagnostic arrangements of odontodes following Eigenmann (1918).Although the identification literature used is quite dated, the geographical proximity to the type locality (Santo Antonio de Madeira in the vicinity of Porto Velho) is consistent with the occurrence of this hematophageous species in the Bolivian Amazon.Especially as their hosts (large pimelodid catfish) can surpass the cataracts of the Madeira River between Porto Velho and Guayaramerín (Goulding 1979).At least three species of Vandellia occur in the Bolivian Amazon of which one appears to be new to science (Hablützel unpublished data).
Trichomycterus tiraquae (Fowler 1940) has not been included in the checklist by Carvajal-Vallejos and Zeballos Fernández (2011) 2010) in a German aquarium hobbyist journal (note that this journal is indexed by the Zoological Record).The morphological characters visible from the accompanying picture showing two adult males and the proximity to the type locality leave few doubt about the accuracy of the species identification.Apistogramma acrensis is morphologically quite similar to A. urteagai Kullander 1986, a species also included in this paper.Apistogramma acrensis can be distinguished from the latter by having the lateral band widened posteriorly, reaching a width of about two scale rows in the posterior portion (vs.width of one scale row along the entire length of the lateral band (Staeck 2003)).Future collection efforts in the Bolivian Acre River drainage will certainly lead to several new reports for Bolivia, as its ichthyofauna is quite distinct from the remaining Bolivian Amazon, which entirely belongs to the upper Madera River drainage.
Specimens of Apistogramma urteagai in the collection of the CBF have been identified using the accurate morphological description by Kullander (1986).The collection site is situated in the Madre de Dios River drainage about 250 km downstream of the type locality.
Osteoglossiformes -Osteoglossidae Arapaima gigas (Schinz 1822) is considered as an exotic species (Sarmiento and Barrera 2004;Hrbek et al. 2005;Carvajal-Vallejos et al. 2011).Interestingly, when screening old literature concerning the Bolivian ichthyofauna, we found an anecdotal report by Heath (1883), stating that the species is native to the lower course of the río  1. Fish taxa of the Bolivian Amazon not included in neither Pouilly et al. (2010) nor Carvajal-Vallejos and Fernández Zeballos (2011) along with information about reference and currently known geographic distribution.+ type locality within Bolivian Amazon.
Beni, but extremely rare (allegedly restricted to the lake "Mamorebey").Although not too much faith should be put in such 19 th century statements, A. gigas has been well known as an important target species for fisheries at the time and species misidentification may be unlikely because of its unique morphology.However, this anecdotal report does certainly not fulfill today's requirements for biodiversity inventories and genetic analysis (Hrbek et al. 2005) as well as population dynamics over the past 30 years (Carvajal-Vallejos et al., 2011) support a recent introduction of A. gigas in the Bolivian Amazon.
How many fish species are there in the Bolivian Amazon?Over the last 25 years, several numbers have been published to answer this question.Starting at 389 (Lauzanne et al. 1991), the reported number of species continuously increased to 688 (Chernoff et al. 2000) and 973 (Pouilly et al. 2010).Whereas the latter two studies uncritically compiled data from the literature, Carvajal-Vallejos and Zeballos Fernández (2011) evaluated the reliability of the available data and combined it with own records.They corrected the estimate by Pouilly et al. (2010), which suffered from questionable records and misidentifications, to 714 species.Here, we add 21 other species to the list and many species may still await their discovery.However, several species may still have to be discarded from current lists as misidentifications and future revisions will therefore not necessarily lead to a higher number of reports.Certainly, future checklists should be more critical regarding false reports and every new report should be accompanied by at least a brief list of identification criteria and, if available, a color picture of the examined specimens.