Checklist and practical identification key for the cichlid fishes (Cichliformes: Cichlidae) of the La Plata drainage in Bolivia, including three new geographical records

Catálogo e identificación práctica para peces cíclidos (Cichliformes: Cichlidae) de la cuenca La Plata en Bolivia, incluye tres nuevos registros geográficos

Pascal I. Hablützel¹* and Robert B. Huanto²

¹Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium
²Museo de Historia Natural Noel Kempff Mercado, Avenida Irala 565, Casilla postal 2489, Santa Cruz, Bolivia

Recibido: 28.09.19, Aceptado: 22.01.20.

Abstract

In comparison with the Bolivian Amazon, the ichthyofauna of the La Plata drainage of Bolivia received relatively little attention historically. Until now, 14 species of cichlid fish have been registered from this area. After an exhaustive review of museum collections (Museo de Historia Natural Noel Kempff Mercado and Colección Boliviana de Fauna), we can report three additional species: Astronotus crassipinnis, Mesonauta festivus and Satanoperca pappaterra. Four other species, which have been listed in previous publications, can be confirmed for the La Plata drainage of Bolivia based on the examination of voucher specimens: Aequidens plagiozonatus, Apistogramma commbrae, A. trifasciata and Crenicichla vittata. As such, 16 of the 17 species can be referenced with voucher specimens in museum collections. We also provide an identification key for the cichlid fish species of the study area.

Key words: Biogeography, Checklist, Freshwater fish, New report, Paraguay river.

Resumen

En comparación con la Amazonia boliviana, la ictiofauna de la Cuenca de la Plata en Bolivia recibió relativamente poca atención históricamente. Hasta el momento, se han registrado 14 especies de peces cíclidos de esta área. Después de una revisión exhaustiva de las colecciones de los museos (Museo de Historia Natural Noel Kempff Mercado y Colección Boliviana de Fauna), podemos informar que se adicionan tres especies: Astronotus crassipinnis, Mesonauta festivus y Satanoperca pappaterra. Otras cuatro especies, que han sido incluidas en publicaciones anteriores, pueden confirmarse para la Cuenca de La Plata en Bolivia con base en revisiones de especímenes voucher: Aequidens plagiozonatus, Apistogramma commbrae, A. trifasciata y Crenicichla vittata. Como tal, 16 de las 17 especies pueden ser referenciadas con especímenes de lotes en colecciones de los museos. También proporcionamos una clave de identificación para las especies de cíclidos del área de estudio.

Palabras clave : Biogeografía, Catálogo, Nuevo registro, Peces de agua dulce, Río Paraguay.

Introduction

The fish fauna of Bolivia is one of the richest in the world (Sarmiento & Barrera 2004, Carvajal-Vallejos et al. 2014, Sarmiento et al. 2014). Unfortunately, it remains poorly documented in the scientific literature. This is particularly the case for the Bolivian part of the La Plata basin, which comprises the Paraguay river in the eastern part of the country, and the rivers Pilcomayo and Bermejo in the south (Figure 1). The first accounts on fish in the Bolivian part of the La Plata basin that include cichlids have been made by Haseman in 1909, who collected fish for the Carnegie Museum (USA). All cichlids he reported from Bolivia are from Puerto Suárez (Haseman 1911) in the río Paraguay drainage. The location 'São Francisco, Bolivia' in Haseman's (1911) work is actually located in Brazil ('Río São Francisco, into Paraguay river, Matto Grosso'; Eigenmann (1911)). In the 1950's, Travassos collected several fish species, including cichlids, in the Paraguay and Otuquis drainages, but did not identify them at species level (Travassos 1957). In 1970, Terrazas Urquidi published a first list of the Bolivian fish species. The sources for his reports on Apistogramma taeniata (Günther, 1862), A. trifasciata (Eigenmann & Kennedy 1903), A. corumbae (Eigenmann & Ward 1907) and Crenicichla vittata Heckel, 1840 from the Bolivian río Paraguay drainage remain, however, unclear. In the 1980s, Kullander wrote a series of taxonomic accounts on the cichlid fishes of the río Paraguay drainage (Kullander 1981, 1982a-c, 1984, 1987). However, with the exception of the first descriptions of A inconspicua Kullander 1983 and Bujurquina oenolaemus Kullander 1987, he did not include Bolivian specimens.

Since the 1990's several extensive surveys have been conducted by Bolivian researchers mostly affiliated to the Museo de Historia Natural 'Noel Kempff Mercado' (MHNNKM) in Santa Cruz de la Sierra. With the notable exception of the article by Farell & Cancino (2007), these studies have been published in governmental reports and academic theses which are unfortunately not readily accessible. For most of the species lists published in governmental reports, little metadata (such as sampling sites, dates, information on species identification, pictures, or lists of voucher specimens etc.) is available. Because of these limitations and since the species identification is not verifiable in most cases, we refrain from citing this grey literature in the present study, although we consider its content very valuable.

Geographical species records provide the basis of local, regional or national inventories on which biodiversity measures can be estimated, they can be used to study biogeographical patterns or they enable us to monitor changes in biodiversity through time (Olden et al. 2010). Regarding this importance, the publication of such records should follow certain standards allowing the verification of species identification. In this study, we report on the species of cichlid fishes from the Bolivian part of the La Plata drainage. We aim not only to report a species list, but also to link records to voucher specimens in museum collections, to provide photographs of new records and to facilitate future identification with a regional identification key.

Study area

The study area includes the Bolivian part of the La Plata drainage in the departments Santa Cruz, Chuquisaca and Tarija (Fig. 1). The major sub-drainages in this area are the rivers Paraguay, Pilcomayo (into río Paraguay at the Paraguayan-Argentinian border) and Bermejo (into río Paraguay in Argentina). A sub-drainage of minor importance is the Parapeti river fan (note that the río Parapetí itself currently drains to the Amazon). The Parapeti river fan consists exclusively of intermittent rivers.

Methods

We report the cichlid species present in the collections of the Coleccion Boliviana de Fauna and the Museo de Historia Natural 'Noel Kempff Mercado' in La Paz and Santa Cruz de la Sierra, respectively. Fish re-identification took place in 2010. Besides a few exceptions, newer collections are therefore not considered in this study. The list of lots in this study should not be considered complete for various reasons (e.g. not being available or not yet catalogized at the time the examination took place). Fish were identified using the primary taxonomic literature (e.g. Kullander 1983, 1986, Kullander & Silfvergrip 1991, Kullander & Ferreira 2006, Varella 2011, Ottoni 2018). For morphometric and meristic characters as well as for colour and scale patterns we follow Kullander (1980, 1983, 1986). Many collection numbers in the MHNNKM have been changed in recent years. To avoid confusion, we also provide the old numbers in brackets. Abbreviations: MNKP = Museo de Historia Natural 'Noel Kempff Mercado' (P = peces). CBF = Coleccion Boliviana de Fauna.

To assess the completeness of the species list provided in this study statistically, we estimated rarefaction curves using the rarecurve function of the package vegan v2.5-2 (Oksanen et al. 2007) in R v3.4.2 (R Development Core Team 2012).

Results

Aequidens plagiozonatus Kullander 1984

Aequidens plagiozonatus Kullander, 1984: 155, Fig. 1. Type locality: Brazil, State of Mato Grosso, R. Paraguay system Mun. Itiquira, internal lakes of the Piquiri-Itiquira system, Fazenda Santo Antonio do Parafso. Holotype: MZUSP 28232.

Bibliography for the study area

Aequidens plagiozonatus; Farell & Cancino (2007): localities (Río Aguas Calientes, upper río Paraguay drainage).

Identification. Species most frequently misidentified as members of the genus Aequidens belong to genera Bujurquina, Cichlasoma and Laetacara. Bujurquina differs from the other genera by having conspicuous lateral and nape bands. Laetacara has a dark stripe from the eye to the tip of the snout and a scaled preoperculum (vs. no dark stripe and preoperculum naked). Cichlasoma differs from the other genera in having scale rows in the proximal area of the rayed part of the dorsal fin and 5 vertical bars behind the midlateral spot (vs. 3-4 in Aequidens, Kullander (1986)). Aequidens plagiozonatus is the only species of its genus to have been reported and confirmed from the upper río Paraguay drainage. It is medium sized and reaches 10.3 cm SL (Kullander 1984). See figure 2 for general appearance. A detailed description and diagnosis can be found in Kullander (1984).

Apistogramma borellii (Regan 1906)

Heterogramma borellii Regan, 1906: 63. Type locality: Caradasiño, Matto Grosso. Syntypes: BMNH 1900.4.14.12-15 (3; one lost).

Heterogramma ritense Haseman, 1911: 362, pl. 70. Type locality: Santa Rita, Río Santa Rita of the Paraguay basin. Holotype: FMNH 54187 [ex CM 2765a].

Heterogramma rondoni Miranda Ribeiro, 1918: 16, pl. 11. Type locality: Caceres, na Caiçara (Campina) [Caceres, at Caiçara (Campina)]. Lectotype: MNRJ 1247A, designated by Miranda Ribeiro (1953: 397).

Apistogramma aequipinnis Ahl, 1938: 246. Type locality: vermutlich Argentinien [probably Argentina]. Holotype: ZMB 23409.

Apistogramma reitzigi Mitsch-Königsdörfer, 1938: 181. Type locality: Wahrscheinlich mittleres Südamerika [probably central South America]. No type specimens.

Apistogramma reitzigi Ahl, 1939: 81: Wahrscheinlich Amazonas, Brasilien [probably Amazon, Brazil]. Holotype: ZMB 23408.

Apistogramma borellii; Terrazas Urquidi (1970): listing (R. Paraguay).

Apistogramma borellii; Schindler & Staeck (1993): listing (upper río Paraguay drainage).

Examined material. Bolivia: río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 3215 (3927), 1, Laguna Mandioré, K. Osinaga, 15 Jul 1998. MNKP 4586 (3504), 12, Hacienda Vista Hermosa, laguna, K. Osinaga & P. Coro, 19 Sep 1999. Gérman Busch: MNKP 1177 (1643), 4, Puerto Suárez, Laguna Cáceres, San Eugenio, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 19 Feb 1996. MNKP 1178 (1646), 1, Puerto Suárez, Laguna Cáceres, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 22 Feb 1996. MNKP 1180 (1667), 2, Laguna Cáceres, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 22 Feb 1996 (lot also contains 1 specimen of Cichlasoma dimerus). MNKP 1183 (1671), 3, Puerto Suárez, Laguna Cáceres, Palo Santo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 22 Feb 1996. MNKP 1217 (2260), 4, Puerto Quijarro, Tamarinero, Canal Tamengo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 26 Feb 1996. MNKP 1219 (2732), 10, Puerto Quijarro, bahia Caceres, Canal Tamengo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 26 Feb 1996 (lot also contains 1 specimen of Cichlasoma dimerus). MNKP 1222 (4229), 5, Puerto Suárez, Laguna Cáceres, curiche temporal, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 19 Feb 1996. MNKP 1393 (1491), 2, Puerto Suárez, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 9 Aug 1996. MNKP 1401 (1496), 1, Puerto Suárez, río San Lorenzo, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 6 Aug 1996. MNKP 1416 (1517), 3, Puerto Suárez, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 6 Aug 1996. MNKP 1444 (1560), 2, Puerto Quijarro, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 13 Aug 1996. MNKP 1445 (1566), 11, Puerto Suárez, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 9 Aug 1996. MNKP 1511 (2255), 18, Puerto Quijarro, Tamarinero, Laguna Cáceres, P. Rebolledo, K. Osinaga, L. Paniagua, L. Paredes & V. Fuentes, 13 Aug 1996. MNKP 1518 (2734), 5, Puerto Suárez, Laguna Cáceres, P. Rebolledo, K. Osinaga, L. Paniagua, L. Paredes & V. Fuentes, 11 Aug 1996. MNKP 1520 (2743), 1, Puerto Quijarro, Tamarinero, Laguna Cáceres, P. Rebolledo, K. Osinaga, L. Paniagua, L. Paredes & V. Fuentes, 15 Aug 1996. MNKP 2402 (2727), 2, Puerto Suárez, Laguna Cáceres, MA. Parada & R. Yañez, 25 May 1997. MNKP 3882 (3055), 7, Puerto Suárez, Laguna Cáceres, K. Osinaga & J. Cardona, 26 Oct 1998. MNKP 3922 (4064), 6, río Pimiento, Laguan Caceres, K. Osinaga & J. Cardona, 28 Oct 1998. MNKP 3932 (4175), 2, Laguna Cáceres, curichi Estancia Verdem, K. Osinaga & J. Cardona, 28 Oct 1998. MNKP 3954 (3219), 59, poza sobre el camino a la hacienda Santa Elena (Otuquis), K. Osinaga & J. Cardona, 31 Oct 1998 (lot also contains 3 specimens of A. commbrae). MNKP 3963 (6153), 4, poza sobre el camino a la hacienda Santa Elena (Otuquis), K. Osinaga & J. Cardona, 31 Oct 1998. MNKP 4010 (3886), 10, Bahia Corea, 'Otuquis', K. Osinaga, J. Cardona, A. Justiniano & M. Chavez, 5 Nov 1998. MNKP 4041 (3054), 1, El Carmen, Est. Campo en medio camino a 2 km al suroeste, K. Osinaga & J. Cardona, 10 Nov 1998.

Identification. To date, four species of Apistogramma have been verifiably reported from the upper río Paraguay drainage: A. borellii, A. commbrae, A. inconspicua and A. trifasciata (e.g. Kullander, 1982c; Menezes et al, 1998). Apistogramma borellii differs from A. trifasciata by the absence of an oblique black stripe between pectoral and anal fin origin and from A. commbrae and A. inconspicua by having the posteriormost vertical bar and caudal spot separated. Preserved specimen shows a series of separated midlateral spots on the flanks. Apistogramma borellii is a small species reaching a size of 3.9 cm SL (Kullander 2003).

Apistogramma commbrae (Regan 1906)

Heterogramma commbrae Regan, 1906: 64. Type locality: Carandasinho, Matto Grosso; Colonia Risso, Alto Paraguay. Lectotype: BMNH 1900.4.14.16, designated by Kullander (1982b: 36).

Heterogramma corumbae Eigenmann & Ward in Eigenmann, McAtee & Ward, 1907: 146, pl. 45 (Fig. 3). Type locality: Co rumba. Holotype: CAS 33719 [ex IU 10166].

Bibliography for the study area

Apistogramma corumbae; Terrazas Urquidi (1970): listing (R. Paraguay).

Examined material: Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 3216 (3927), 1, Laguna Mandioré, K. Osinaga, 15 Jul 1998. MNKP 4591 (3504), 1, Hacienda Vista Hermosa, laguna, K. Osinaga & P. Coco, 20 Sep 1999. Chiquitos: MNKP 5270, 13, Candelaria, río Tucavaca, M.E. Farell, MÁ. Velásquez & P. Hinojosa, 29 Dec 2003. Germán Busch: MNKP 1488 (1526), 5, Puerto Suárez, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 13 Aug 1996. MNKP 2949 (1966), 1, Puerto Suárez, Hacienda Arcoiris, Laguna Cáceres, MA. Parada & V. Fuentes, 1997. MNKP 3954 (3219), 3, poza sobre el camino a la hacienda Santa Elena, K. Osinaga & J. Cardona, 31 Oct 1998 (lot also contains 59 specimens of C. borellii). MNKP 3981 (3236), 1, poza camino a Santa Elena a 10 km de hacienda Las Camelias, K. Osinaga & J. Cardona, 1 Nov 1998. MNKP 6599 (3522), 1, río Santo Rosario, K. Osinaga & P. Coro, 1 Oct 1999.

Identification. Apistogramma commbrae differs from A. trifasciata by the absence of an oblique black stripe between pectoral and anal fin origin and from A. borellii by having the posteriormost vertical bar and caudal spot fused to a tail spot. In A. commbrae, the dark midlateral band is clearly fused with the tail spot, while in A. inconspicua, the band is somewhat separated from it. Preserved specimen of A. commbrae show several typically conspicuous longitudinal stripes along the flanks below the lateral band (less conspicuous or absent in A. inconspicua). Additional characters to distinguish A. commbrae from A. inconspicua are: modally 16 dorsal fin spines (vs. 15) and teeth on the posteromedial portion of the pharyngeal tooth plate bicuspid (vs. tricuspid; Kullander 1982c). It is a small species reaching 32.6 mm SL (Kullander 1982b). See figure 3 for general appearance. A detailed redescription of A. commbrae can be found in Kullander (1982b).

Apistogramma trifasciata (Eigenmann & Kennedy 1903)

Biotodoma trifasciatus Eigenmann & Kennedy, 1903: 536. Type locality: Arroyo Chagalalina [Paraguay]. Holorype: CAS 33721.

Heterogramma trifasciatum masiliense Haseman, 1911: 360, pl. 62 (fig. 2). Type locality: Sao Antonio de Guapore. Syntypes: CAS 33722 (1), FMNH 54177 (2), one missing. Spelled macielense on p. 360.

Apistogramma trifasciatum haraldschultzi Meinken, 1960: 291, fig. 1. Type locality: Oberer Guapore, auch Itenes genannt, im Nordes des Staates Matto Grosso [upper Guaporé, also called Itenes, in the north of the state Matto Grosso]. Holotypes: ZMH H1209. Originally as harald schultzi as a subspecies of trifasciatum; here regarded as one name to be combined.

Bibliography for the study area

Apistogramma trifasciata; Schindler & Staeck (1993): listing (upper río Paraguay drainage).

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 3188 (3921), 7, Puerto Gonzalo, río Pando, K. Osinaga, 12 Jul 1998. MNKP 3214 (3927), 2, Laguna Mandioré, K. Osinaga, 15 Jul 1998. MNKP 4592 (3504), 1, Hacienda Vista Hermosa, laguna, K. Osinaga & P. Coro, 20 Sep 1999.

Identification. Differs from all other species of Apistogramma by having an oblique black stripe between pectoral and anal fin origin. This stripe is absent in living specimens of at least one population in the Bolivian Amazon (personal observation), but seems to be always present in preserved animals. Apistogramma trifasciata is a small species reaching a size of 3.8 cm SL (Kullander 2003). See figure 4 for general appearance of the species.

Apistogramma sp. (unidentified juveniles)

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 4611 (3453), 6, laguna, Hacienda Vista Hermosa, laguna, K. Osinaga & P. Coro, 21 Sep 1999.

Astronotus crassipinnis (Heckel 1840)

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 4810 (3600), 1, Santo Rosario, río Santo Rosario, K. Osinaga & P. Coro, 1 Oct 1999. Gérman Busch: MNKP 1262 (1801), 1, Puerto Suárez, Hacienda Arcoiris, Laguna Cáceres, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 28 Feb 1996. MNKP 1430 (1532), 1, Puerto Suárez, Castrillo, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 9 Aug 1996. MNKP 3874 (3796), 1, Puerto Suárez, río Pimiento, K. Osinaga &J. Cardona, 23 Oct 1998.

Identification. Astronotus crassipinnis can been identified on the basis of the following unique combination of characters: 'African type' lips (see Figure 12 in Kullander (1986)), unpaired fins densely scaled, about 35 scales in the longitudinal row, no ocelli along the dorsal-fin base. This species is the only one of its genus known to occur in the Río Paraguay basin. It is a large species reaching 24 cm SL (Kullander 2003). See Figure 5 for general appearance. More detailed accounts on the appearance of A. crassipinnis are provided by Kullander (1981, 1986).

Bujurquina oenolaemus Kullander 1987

Bujurquina oenolaemus Kullander, 1987: 196, fig. 1. Type locality: Bolivie, dep. Santa Cruz. Río Aguas Calientes à Aguas Calientes, à 25 km à Test de Roboré, sur le rail. (Basin du Paraguay) [Bolivia, dep. Santa Cruz, Río Aguas Calientes at Aguas Calientes, 25 km west of Robore, on the railroad. (Paraguay basin)]. Holotype: IRSNB 666.

Bibliography for the study area

Bujurquina oenolaemus; Kullander (1987): diagnosis, description, photograph, illustration, locality (Río Aguas Calientes, upper río Paraguay drainage) and voucher specimens (IRSNB 666, IRSNB 667).

Bujurquina oenolaemus; Farell & Cancino (2007): localities (Río Aguas Calientes, upper río Paraguay drainage) and photography.

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Chiquitos: MNKP 4692 (3481), 11, Aguas Calientes, río Aguas Calientes, K. Osinaga & P. Coro, 26-27 Sep 1999. MNKP 5202 (4142), 3, Aguas Calientes, río Aguas Calientes, V. Fuentes & S. Sangueza, 13 Dec 2000. MNKP 5244, 1, Localidad Aguas Calientes, El Playon, naciente del río Aguas Calientes, M.E. Farell, M.A. Velásquez & P. Hinojosa, 5 Jan 2004. MNKP 5282, 6, punto de union de los ríos Jesus y Aguas Calientes, localidad Aguas Calientes, M.E. Farell, M.A. Velásquez & P. Hinojosa, 4 Jan 2004. MNKP 5298, 9, Aguas Calientes, balneario El Burriño, río Aguas Calientes, M.E. Farell, M.A. Velásquez & G. Huanca, 5 Jul 2004. MNKP 5352, 1, Aguas Calientes, zona El Playon, río Aguas Calientes, M.E. Farell, M.A. Velásquez & G. Huanca, 5 Jul 2004. MNKP 5362, 2, Aguas Calientes, punto de union río Aguas Calientes y río Jesus, M.E. Farell, M.A. Velásquez & G. Huanca, 5 Jul 2004.

Identification. Differs from B. vittata by having a shorter pectoral fin (29-33 vs. 36-41 % of SL) and a longer head (38-41 vs. 35-38 % of SL). Body with a dark reddish/ wine-coloured hue when alive, brachiostegal membrane reddish (vs. yellowish). Bujurquina oenolaemus is a small species reaching 7.1 cm SL (Habliitzel, unpublished data).

Bujurquina vittata (Heckel 1840)

Acara vittatus Heckel, 1840: 346. Type locality: ... Sümpfen um Cujabá, der Hauptstadt in der Provinz Matagrosso [Swamps in the vicinity of Cujabá, the capital of the province Matagrosso]. Holotype: NMW 33879.

Aequidem paraguayensis Eigenmann & Kennedy, 1903: 534. Type locality: Asuncion. Holotype: CAS 34716 [ex IU 10066].

Bibliography for the study area

Aequidens paraguayensis; Haseman (1911): localities (Puerto Suárez, upper río Paraguay drainage) and voucher material (Ichthyological Collection of the Carnegie Museum Nos. 999, 2534a-k).

Aequidens paraguayensis; Terrazas Urquidi (1970): listing (Río Pilcomayo and Río Paraguay).

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: CBF 8679, 1, Pantanal, Río Las Conchas, Estancia Las Conchas, arroyo "submontano" de "aguas negras", con presencia de grandes pozas, rápidos y cataratas, 17° 33' 58.3"S 59° 28' 17.1"W, J. Sarmiento & K. Osinaga, 17 Apr 1999. CBF 8683, 6, Pantanal, Río Las Conchas, Estancia Las Conchas, arroyo "submontano" de "aguas blancas", con alternancia de rápidos y pozas, 17° 33' 58.3"S 59° 28' 17.1"W, J. Sarmiento & K. Osinaga, 16 Apr 1999. MNKP 739 (589), 1, San Matías, Estación Cascabel, M.L. Argandoña, 8 Sep 1994. MNKP 742 (535), 2, San Matías, Estancia Cascabal, M.L. Argandoña, 8 Sep 1994. MNKP 3227 (4903), 2, Laguna Mandioré, K. Osinaga, 16 Jul 1998. MNKP 4727 (3613), Santo Corazon, río Santo Corazon, K. Osinaga & P. Coro, 28 Sep 1999. MNKP 4816 (6600), 3, río Santo Rosario, K. Osinaga & P. Coro, 1 Oct 1999. Chiquitos: MNKP 4877 (3355), 1, Carmen Rivero Torrez. río Otuquis, V. Fuentes & S. Sangueza, 1 Nov 1999. MNKP 4867 (4250), 1, río Tucavaca, V. Fuentes & S. Sangueza. MNKP 5232, 1, Laguna al lado derecho del Camino, 800 m antes de la localidad de Candelaria, M.E. Farell, M.A. Velásquez & P. Hinojosa, 29 - 30 Dec 2003. MNKP 5328, 1, Localidad Candelaria, río Aguas Calientes, M.E. Farell, M.A. Velásquez & G. Huanca, 2 Jul 2004. MNKP 5363, 3, Candelaria, río Tucavaca, M.E. Farell, M.A. Velásquez & G. Huanca, 30 Jun 2004. Germán Busch: MNKP 3953 (3209), 4, poza en el camino a hacienda Santa Elena, K. Osinaga & J. Cardona, 31 Oct 1998.

Identification. Differs from B. oenolaemus by a longer pectoral fin (36-41 vs. 29-33 % of SL) and a shorter head (35-38 vs. 38-41 % of SL). Body (at least ventral portions of head and flanks) with a yellowish hue when alive, brachyostegal membrane yellowish. A brief redescription of B. vittata is provided by Kullander (1981). Bujurquina vittata is a small species reaching 7.9 cm SL (Hablützel, unpublished data).

Chaetobranchopsis australis Eigenmann & Ward, 1907

Chaetobranchopsis australis Eigenmann & Ward in Eigenmann, McAtee & Ward, 1907: 144, pl. 44 (fig. 1). Type locality: Bahia Negra [Paraguay]. Holotype: CAS 66954 [ex. 10157].

Bibliography for the study area

Chaetobranchopsis australis; Haseman (1911): locality (Puerto Suárez, upper río Paraguay drainage) and voucher material (Ichthyological Collection of the Carnegie Museum No. 2498).

Chaetobranchopsis australis; Farell & Cancino (2007): locality (Río Tucavaca, upper río Paraguay drainage).

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: CBF 8686, 1, Pantanal, Río Las Conchas, Estancia Las Conchas, arroyo "submontano" de "aguas blancas", con alternancia de rápidos y pozas, 17° 33' 58.3"S 59° 28' 17.1"W, J. Sarmiento & K. Osinaga, 16 Apr 1999. MNKP 2459 (2175), 1, Hacienda Santa Helena, río Mercedes, R. Coca & Maraz, 22 Sep 1997. Germán Busch: MNKP 3929 (2997), 1, Puerto Suárez, Estación Verde, Laguna Cáceres, K. Osinaga &J. Cardona, 28 Oct 1998. MNKP 3947 (3033), 22, poza en el camino a la hacienda Santa Elena (Otuquis), K. Osinaga & J. Cardona, 31 Oct 1998.

Cichla piquiti Kullander & Ferreira 2006

Cichla piquiti Kullander & Ferreira, 2006: figs. 49-54. Type locality: Brazil: Para: Río Itacaiunas at Caldeirao. Holotype: MZUSP 40296.

Bibliography for the study area

Cichla piquiti; Sarmiento et al. (2014): listing (Paraguay-Parana Basin).

Examined material. None.

Identification. The genus Cichla can be readily distinguished from other South American cichlids by its large size, the deeply notched dorsal-fin margin, the small scales, the densely scaled unpaired fins and the conspicuous ocellus on the base of the caudal fin. Cichla piquiti and C. kelberi Kullander & Ferreira, 2006 are the only species of Cichla reported from the upper río Paraguay (both introduced; Kullander & Ferreira 2006). They can readily be distinguished on the number of vertical bands below the dorsal fin: three in C. piquiti vs. five in C kelberi. Cichla piquiti is a large species reaching 43 cm SL (Kullander & Ferreira 2006).

Cichlasoma dimerus (Heckel 1840)

Acara marginatus Heckel, 1840: 350. Type locality: Nahe von Cujaba [Vicinity of Cujaba]. Holotype: NMW 33673

?Heros centralis Holmberg, 1891: 183. Type locality: Repúplica Argentina, Provincia de Santiago del Estero. Type lost.

Bibliography for the study area

Aequidens portalegrensis; Haseman (1911): localities (Puerto Suárez, upper río Paraguay drainage) and voucher material (Ichthyological Collection of the Carnegie Museum Nos. 993, 2763a-e and2764a-h).

Cichlasoma dimerus; Kullander (1983): locality (R. San Rafael, 4 km S Robore, upper río Paraguay drainage) and voucher material (IRSNB 20.272).

Cichlasoma boliviense; Farell & Cancino (2007): locality (Río Roboré, upper río Paraguay drainage).

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: CBF 8623, 3, Pantanal, pantano con lagunilla, 17°04'10.5"S 59^o28'17.r'W, J. Sarmiento & K. Osinaga, 19 Apr 1999. CBF 8651, 11, Pantanal, Lago Santa Elena, J. Sarmiento & K. Osinaga, 20-21 Apr 1999. MNKP 736 (537), 2, San Matías, Estancia Cascabel, M.L. Argandoña, 8 Sep 1994. MNKP 740 (535), 5, San Matías, Estancia Cascabal, M.L. Argandoña, 8 Sep 1994. MNKP 2416 (2112), 1, a 3 km de San Matías, debajo del puente, R. Coca & Maraz, 20 Sep 1997. MNKP 2418 (2156), 2, a 3 km de San Matías, debajo del puente, R. Coca, Maraz, 20 Sep 1997. MNKP 2426 (2193), 1, a 3 km de San Matías, debajo del puente, R. Coca & Maraz, 20 Sep 1997. MNKP 2441 (2209), 1, camino a curiche la Hormiga a 14 km de San Matías, Curichi Patujusal, R. Coca & Maraz, 21 Sep 1997. MNKP 3228 (6116), 7, Puerto Gonzalo, Laguna Mandioré, K. Osinaga, 16 Jul 1998. MNKP 3270 (4903), 4, Laguna Mandioré, K. Osinaga, 16 Jul 1998. MNKP 4746 (3518), 4, Curiche Tapera, K. Osinaga & P. Coro, 29 Sep 1999. MNKP 4612 (3453), 1, laguna, Hacienda Vista Hermosa, laguna, K. Osinaga & P. Coro, 21 Sep 1999. MNKP 6147, 1, río Bella Boca, V. Fuentes, 23 Nov 2000. Chiquitos: MNKP 4892 (3371), 1, río Bravo, V. Fuentes & S. Sangueza, 5 Nov 1999. MNKP 4850 (3410), 5, río Aguas Calientes, V. Fuentes, S. Sangueza, 31 Oct 1999. MNKP 3792, 1, río Esperancita, M. Velásquez & V. Fuentes, 2 Feb 2006. MNKP 5353, 2, río Aguas Calientes, zona El Playon, Aguas Calientes, M.E. Farell, M.A. Velásquez & G. Huanca, 5 Jul 2004. Germán Busch: MNKP 1155  (1537), 1, Puerto Suárez, Laguna Cáceres, Palo Santo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 19 Feb 1996. MNKP 1156  (1548), 3, Puerto Suárez, Hacienda San Lorenzo, río San Lorenzo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 29 Feb 1996. MNKP 1180 (1667), 1, Puerto Suárez, Laguna Cáceres, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 22 Feb 1999 (lot also contains 2 specimens of Apistogramma borellii). MNKP 1195 (1739), 1, curiche temporal, Laguna Cáceres, Puerto Suárez, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 19 Feb 1996. MNKP 1218 (2261), 1, Puerto Quijarro, Tamarinero, Canal Tamengo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 26 Feb 1996. MNKP 1219 (2732), 10, Puerto Quijarro, bahia Caceres, Canal Tamengo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 26 Feb 1996 (lot also contains 10 specimens of Apistogramma borellii). MNKP 1223 (4229), 2, Puerto Suárez, Laguna Cáceres, curiche temporal, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 19 Feb 1996. MNKP 1327 (1561), 2, Puerto Suárez, Laguna Cáceres, Hacienda Arcoiris, K. Osinaga, V. Fuentes, A. Justiniano & E. Guzman, 19 May 1996. MNKP 1394 (1491), 1, Puerto Suárez, Laguan Caceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 9 Aug 1996. MNKP 1427 (1528), 1, Puerto Suárez, Laguna Cáceres, Castrillo, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 9 Aug 1996. MNKP 1429 (1531), 7, Puerto Suárez, Laguna Cáceres, Hacienda Arcoiris, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 4 Aug 1996. MNKP 1516 (2255), 1, Puerto Quijarro, Tamarinero, Laguna Cáceres, P. Rebolledo, K. Osinaga, L. Paniagua, L. Paredes & V. Fuentes, 13 Aug 1996. MNKP 2193 (2035), 44, El Carmen, zona de inundación, estancia Campo el Medio, P. Rebolledo, R. Coca, V. Fuentes & G. Soto, May 1997. MNKP 2197 (2051), 1, El Carmen, zona de inundacion, estancia Campo el Medio, P. Rebolledo, R. Coca, V. Fuentes & G. Soto, May 1997. MNKP 2293 (2046), 1, Puerto Busch, Isla Santa Rosa, río Paraguay, R. Coca, V. Fuentes & G. Soto, 14 May 1997. MNKP 3902 (3017), 7, Puerto Suárez, río Pimiento, K. Osinaga & J. Cardona, 27 Oct 1998. MNKP 3907 (3201), 2, Puerto Suárez, Laguna Cáceres, Pto. Arcoiris, río Pimiento, K. Osinaga, J. Cardona, 27 Oct 1998. MNKP 3928 (2995), 2, Puerto Suárez, Laguna Cáceres, Est. Verde, K. Osinaga & J. Cardona, 28 Oct 1998. MNKP 3960 (4321), 33, Poza en el camino a Hacienda Santa Elena, río Otuquis drainage, K. Osinaga & J. Cardona, 31 Oct 1998. MNKP 4021 (3018 and 3026), 2, El Carmen, zona de inundación, Estancia Campo el Medio, K. Osinaga & J. Cardona, 9 Nov 1998. MNKP 4037 (3037), 19, El Carmen, Estancia Campo en Medio, curichi a 2 km suroeste, K. Osinaga & J. Cardona, 10 Nov 1998. MNKP 4046 (3261), 18, El Carmen, Estancia Campo en Medio, curichi a 2 km suroeste, K. Osinag &, J. Cardona, 10 Nov 1998. MNKP 4319, 2, Santa Ana, río la Canoa, V. Fuentes, 21 Oct 2000. MNKP 5085 (4327), 2, Sta. Ana, Poza La Banda, Santa Ana, V. Fuentes, 20 Oct 2000. río Bermejo drainage: Tarija: Arce: CBF 8605, 4, Río Bermejo, Ciudad de Bermejo: Punto 2, 22°47"S 64°20'W, J. Horton, 27 Dec 1993.

Identification. As described in Kullander (1983). Most adult or sub-adult specimen of Cichlasoma boliviense, a species from adjacent areas in the Amazon, have scale-base spots on the posterioventral parts of the sides, resulting in a mottled pattern, which are absent in C. dimerus. The two species overlap in measurements and meristics (Kullander 1983), making it virtually impossible to distinguish them by morphology in some cases. However, no specimen with mottled colouration pattern have yet been observed in the La Plata drainage, indicating that C. boliviense is indeed restricted to the Amazon. Cichlasoma dimerus is a medium-sized species reaching 11.7 cm SL (Kullander 1983).

Crenicichla lepidota Heckel, 1840: 429, pl. 30 (fig. 13). Type locality: Río -Guaporè. Lectotype: NMW 33101, designated by Ploeg(1991:42).

Crenicichla edithae Ploeg, 1991: 29, fig. 24. Type locality: Paraguay, Río Paraguai system, Arroyo Itabu-Guazu. Holotype: MHNG 2028.45.

Bibliography for the study area

Crenicichla lepidota; Haseman (1911): locality (Puerto Suárez, upper río Paraguay drainage) and voucher material (Ichthyological Collection of the Carnegie Museum Nos. 2654a-b, 2661a-c).

Crenicichla lepidota; Terrazas Urquidi (1970): listing (R. Bermejo and R. Paraguay).

Crenicichla lepidota; Farell & Cancino (2007): localities (Río Otuquis drainage, upper río Paraguay drainage).

Crenicichla lepidota; Varella (2011): bibliography.

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: CBF 8652, 1, Pantanal, Lago Santa Elena, Paraguay drainage, J. Sarmiento & K. Osinaga, 20-21 Apr 1999. CBF 8680, 1, Pantanal, Río Las Conchas, Estancia Las Conchas, arroyo "submontano" de "aguas negras", con presencia de grandes pozas, rápidos y cataratas, 17° 33' 58.3"S 59° 28' 17.1"W, J. Sarmiento & K. Osinaga, 17 Apr 1999. MNKP 2417 (2113), 2, río a 3 km de San Matías, debajo del puente, R. Coca & Maraz, 20 Sep 1997. MNKP 2420 (2158), 10, río a 3 km de San Matías, debajo del puente, R. Coca & Maraz, 20 Sep 1997. MNKP 2425 (2187), 1, río a 3 km de San Matías, debajo del puente, R. Coca & Maraz, 20 Sep 1997. MNKP 2435 (2169), 2, Curichi Patujusal, camino al curiche La Hormiga, 14 km a San Matías, R. Coca & Maraz, 21 Sep 1997. MNKP 4716 (3490), 1, Santo Corazon, río Santo Corazón, K. Osinaga & P. Coro, 28 Sep 1999. MNKP 4747 (3519), 2, Curiche Tapera, K. Osinaga & P. Coro, 29 Sep 1999. MNKP 4105 (3611), 1, pantano, viejo cauce de río , J. Sarmiento, K. Osinaga, F. Osorio & R. Bueno, 23 Apr 1999. MNKP 4587 (3506), 1, Area de Manejo Integral San Matías, laguna, Hacienda Vista Hermosa, K. Osinaga & P. Coro, 20 Sep 1999. MNKP 3139 (3924), 2, río Pando, Puerto Gonzalo & K. Osinaga, 11 Julio 1998. MNKP 3223 (4151), 1, Laguna Uberaba, K. Osinaga, 4 Jul 1998. MNKP 4105 (3641), 6, Area de Manejo Integral San Matías, Hacienda Pantano Caribe, río Caribe, K. Osinaga & P. Coro, 24 Sep 1999. MNKP 4680 (3643), 4, Area de Manejo Integral San Matías, Hacienda Pantano Caribe, río Caribe, K. Osinaga & P. Coro, 27 Sep 1999. MNKP 4570 (3664), 4, laguna, Hacienda Vista Hermosa, K. Osinaga & P. Coro, 19 Sep 1999. MNKP 4645 (3870), 5, Area de Manejo Integral San Matías, Hacienda Pantano Caribe, río Caribe, K. Osinaga & P. Coro, 27 Sep 1999. MNKP 3223 (4187), 1, Laguna Mandioré, K. Osinaga, 15 Jul 1998. Chiquitos: MNKP 4762 (3622), 7, Aguas Calientes, río Aguas Calientes, K. Osinaga & P. Coro, 26-27 Sep 1999. MNKP 4864 (4123), 2, ?, V. Fuentes & S. Sangueza, Nov 1999. MNKP 5256, 1, laguna al lado del camino, 800 m antes de llegar a Candelaria, M.E. Farell, Ml Velásquez & P. Hinojosa, 30 Dec 2003. MNKP 5269, 31, Candelaria, río Tucavaca, M.E. Farell, M.A. Velásquez & P. Hinojosa, 29 Dec 2003 (lot also contains 1 specimen of C. semifasciata). MNKP 5296, 1, Candelaria, río Aguas Calientes, M.E. Farell, M.A. Velásquez & G. Huanca, 2 Jul 2004. MNKP 5305, 5, laguna al lado derecho del camino, 800 m antes de llegar a la localidad de Candelaria, M.E. Farell, M.A. Velásquez & G. Huanca, 1 Jul 2004. Germán Busch: MNKP 1182 (1670), 1, Puerto Suárez, Palo Santo, Laguna Cáceres, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 21 Feb 1996. MNKP 1403 (1498), 5, Puerto Quijarro, Tamarinero, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 15 Aug 1996. MNKP 1404 (1499), 1, Puerto Quijarro, Tamarinero, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 13 Aug 1996. MNKP 1422 (1521), 1, Puerto Quijarro, Tamarinero, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 8 Aug 1996. MNKP 1424 (1524), 1, Puerto Suárez, Laguna Cáceres, zona de la Bamba antigua, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 11 Aug 1996. MNKP 1484 (1729), 1, Puerto Suárez, Laguna Cáceres, P. Rebolledo, K. Osinaga, L. Paniagua, L. Paredes & V. Fuentes, 9 Aug 1996. MNKP 1425 (1525), 4, Puerto Quijarro, Tamarinero, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua & L. Paredes, 13 Aug 1996. MNKP 1526, 5, Puerto Quijarro, Laguna Cáceres, P. Rebolledo, K. Osinaga, V. Fuentes, L. Paniagua, L. Paredes, 13 de Ago 1996. MNKP 2206 (2083), 3, El Carmen, zona de inundación, Estancia Campo el Medio, P. Rebolledo, R. Coca, V. Fuentes & G. Soto, May 1997. MNKP 3945 (3011), 6, poza en el camino Hacienda Santa Elena, K. Osinaga & J. Cardona, 31 Oct 1998. MNKP 3973 (3036), 4, Camino a Hacienda Santa Elena, K. Osinaga & J. Cardona, 1 Nov 1998. MNKP 3900 (2987), 2, Puerto Suárez, río Jordano Pimiento, K. Osinaga & J. Cardona, 27 Oct 1998. MNKP 3993 (3000), 4, Otuquis, Bahia Corea, K. Osinaga, J. Cardona, A. Justiniano & M. Chavez, 5 Nov 1998.

Identification. A redescription of C. lepidota is provided by Kullander (1982) and Varella (2011). It differs from C. semifasciata by a less depressed head and a longer and more slender snout and from C. vittata by lower longitudinal scale count (34-51 vs. about 79-90 E1 scales). Crenicichla ploegi and C. semicincta are similar and parapatric species. The former can be distinguished from C. lepidota by a higher scale count (58-71 El scales) and the colour pattern (Varella et al 2018). The latter differs from C. lepidota by lacking a ring of iridescent scales around the lateral spot and having this spot elongated and nearly integrated in the midlateral longitudinal band. Crenicichla semicincta, however, has not been reported from the La Plata system and appears to be restricted to the upper río Madera drainage. Crenicichla lepidota is medium-sized reaching 18.9 mm SL (Varella 2011).

Crenicichla semifasciata (Heckel 1840)

Batrachops semifascaitus Heckel, 1840: 436. Type locality: Flusse Paraguay bei Caiçara [Paraguay River at Caiçara]. Types in NMW, not found.

Acharnes chacoensis Holmberg, 1891: 148. Type locality: Formosa. No types known.

Boggiania ocellata Perugia, 1897: 148. Type locality: Puerto 14 de Mayo, dipartamento di Bahia Negra, nel Chaco boreale [Puerto 14 de Mayo, Bahia Negra department, in the boreal Chaco]. Holotype: MSNG 33700.

Crenicichla simoni Haseman, 1911: 345, pl. 59. Type locality: Río Paraguay at São Luiz de Caceres. Holotype FMNH 54097.

Bibliography for the study area

Crenicichla simoni; Haseman (1911): locality (Puerto Suárez, upper río Paraguay drainage) and voucher material (Ichthyological Collection of the Carnegie Museum Nos. 2648a-b).

Batrachops ocellatus; Terrazas Urquidi (1970): listing (R. Paraguay).

Batrachops semifasciatus; Terrazas Urquidi (1970): listing (R. Paraguay).

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Chiquitos: MNKP 5269, 1, Candelaria, río Tucavaca, M.E. Farell, M.A. Velásquez & P. Hinojosa, 29 Dec 2003 (lot also contains 31 specimens of C. lepidota). Germán Busch: MNKP 1216 (2259), 1, Puerto Quijarro, Tamarinero, Canal Tamengo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 26 Feb 1996. MNKP 1220 (2733), 1, Puerto Suárez, Laguna Cáceres, Palo Santo, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 23 Feb 1996.

Identification. Differs from all other Crenicichla species in the Paraguay-Parana drainage by a wider head and a shorter and broader snout. In terms of coloration it differs from the other species by having the base of the scales pigmented, giving the sides a finely reticulated appearance. Crenicichla semifasciata is a medium-sized species reaching 18.5 cm SL (Varella 2011).

Crenicichla vittata Heckel 1840

Crenicichla vittata Heckel, 1840: 417. Type locality: ... Flusse Cuyaba; ... Flusse Paraguay [Cuyaba River, Paraguay River]. Lectotype: NMW 77815, designated by Ploeg (1991: 81). Status as syntype is, however, not supported by collection data. NMW 77770 probable holotype.

Bibliography for the study area

Crenicichla vittata; Terrazas Urquidi (1970): listing (R. Paraguay).

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Chiquitos: MNKP 4853 (3348) río Aguas Calientes, V. Fuentes & S. Sangueza, 1 Nov 1999. Gérman Busch: MNKP 1130 (1384), 1, Puerto Suárez, San Eugenio, Laguna Cáceres, K. Osinaga, R. Coca, V. Fuentes & A. Franco, 19 Feb 1996.

Identification. Crenicichla vittata is straightforward to identify as it is the only Crenicichla species in the Upper Río Paraguay basin with about 83-95 scales in the longitudinal row (Kullander 1981, Ploeg 1991). Other species of Crenicichla known from other drainage systems with a similar scale count lack a suborbital stripe (Ploeg 1991). Differs from C. semifasciata by a less depressed head and a longer and slenderer snout and from C. lepidota by higher longitudinal scale count (about 83-95 vs. about 34-45). It is a large species reaching a size of 29.4 cm SL (Varella 2011). See figure 6 for general appearance. A brief redescription of C vittata is provided by Kullander (1981).

Crenicichla sp. (unidentified juveniles)

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 4780 (3570), many juveniles, Bahia Jesus.

Gymnogeophagus balzanii (Perugia 1891)

Geophagus balzanii Perugia, 1891: 623. Type locality: Villa Maria (Matto Grosso), Río Paraguay a 15°. Holotype: MSNG 7683.

Geophagus duodecimspinosus Boulenger, 1895: 524. Type locality: Paraguay. Holotype: BMNH 1895.5.17.12.

Gymnogeophagus cyanopterus Miranda Ribeiro, 1918: 790. Type locality: Itaqui, Río Grande do Sul. Holotype: MZUSP 2549.

Type locality. Villa Maria (Matto Grosso), Río Paraguay a 15°.

Geophagus balzanii; Haseman (1911): locality (Puerto Suárez, upper río Paraguay drainage) and voucher material (Ichthyological Collection of the Carnegie Museum Nos. 2802a-e).

Gymnogeophagus balzanii; Farell & Cancino (2007): locality (Río Tucavaca, upper río Paraguay drainage).

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 4797 (3522), 4, Santo Rosario, río Santo Rosario, K. Osinaga & P. Coro, 1 Oct 1999. Chiquitos: MNKP 5313, 1, Candelaria, río Tucavaca, M.E. Farell, MA. Velásquez & G. Huanca, 30 Jun 2004.

Identification. Gymnogeophagus balzanii differs from similar species in the study area by having the dorsal fin scaled and lacking a caudal spot. Males develop a conspicuous nuptial bulb on the forehead during the reproductive season. It is the only species of Gymnogeophagus known to occur in the upper reaches of the río Paraguay drainage. It is a medium-sized species reaching 12 cm SL (Kullander 2003).

Laetacara dorsigera (Heckel 1840)

Acara dorsiger Heckel, 1840: 348. Type locality: Sümpfe in der Nähe des Paraguay-Flusses bei Villa Maria [Swamps in the vicinity of the Paraguay River at Villa Maria]. Holotype: NMW 33669.

Bibliography for the study area

Acara dorsigera; Haseman (1911): locality (Puerto Suárez, upper río Paraguay drainage) and voucher material (Ichthyological Collection of the Carnegie Museum Nos. 2565a-f).

Identification. As described in Ottoni & Costa (2009). Laetacara species can be distinguished from similar cichlid genera by the presence of scales on the preoperculum (Kullander 1986). Laetacara dorsigera is a small species reaching 4.0 cm SL (Ottoni 2018).

Mesonauta festivus (Heckel 1840)

Heros festivus Heckel, 1840: 376. Type locality: Fluss Guaporè und dessen nahe gelegenen Moräste [Guaporè River and its closeby swamps]. No types known.

Bibliography for the study area

Examined material. Bolivia: río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 2414 (1984, 2 and 2155, 1), 3, San Matías a 3 km bajo el puente, R. Coca & Maraz, 20 Sep 1997. MNKP 3514 (4547), 1, Area de Manejo Integrado San Matías, Bahia Jesus, K. Osinaga & P: Coro, 30 Sep 1999. MNKP 3254 (3933), 3, Laguna Mandioré, K. Osinaga, 16 Jul 1998. MNKP 5204 (4689), 3, Laguna La Selva, V. Fuentes, 17 Dec 2000.

Identification. The genus Mesonauta can easily be distinguished from other cichlid genera by the presence of a conspicuous black stripe from the lower jaw to the rayed part of the dorsal fin. Further characteristics are the disciform body, the long pelvic spine (reaching beyond the origin of the anal fin) and the high number of anal fin spines (VII-XI; Kullander & Silfvergrip 1991). It is a small species reaching 8 cm SL (Kullander & Silfvergrip 1991). No other species of Mesonauta have been reported from the Río Paraguay basin. See figure 7 for general appearance of the species.

Geophagus pappaterra Heckel, 1840: 396. Type locality: Río-Guapore. Syntypes: 23684-23685 (2).

Examined material. Bolivia: upper río Paraguay drainage: Santa Cruz: Angel Sandoval: MNKP 725 (532), 1, San Matías, Estancia Cascabel, M.L. Argandoña, 8 Sep 1994. Gérman Busch: MNKP 5203 (4147), 1, Laguna La Selva, V. Fuentes, 17 Dec 2000.

Identification. No unambiguous diagnostic characters are currently known for Satanoperca pappaterra to separate it from 5. jurupari. However, the species has frequently been reported from the study area and is the only species of its genus occurring in the La Plata basin. From other geophagine cichlid genera, Satanoperca can be distinguished by the absence of scales on the dorsal fin and the lack of a suborbital stripe. Satanoperca pappaterra is a medium-sized species reaching 17.4 cm SL (Kullander 2003). See figure 8 for general appearance of the species.

Discussion

The examination of 749 specimens in 162 museum lots revealed 16 species of cichlid fishes, while an exhaustive literature review added one additional species (Cichla piquiti), adding up to a list of 17 species in total. Virtually all lots stem from the upper río Paraguay and only one lot (Cichlasoma dimerus) has been collected in the río Bermejo drainage. In the literature, we found only one report from the rivers Bermejo (Chaetobranchus sp.; Sarmiento et al. (2019)) and Pilcomayo (Bujurquina vittata; Terrazas Urquidi (1970)), respectively. All other literature reports are from the río Paraguay.

Sarmiento & Barrera (1997) and Sarmiento et al. (2019) reported Acaronia sp. from the río Pilcomayo basin. According to the CBF catalog, these specimens are from the río Bermejo (CBF 03627, Acaronia sp., 03 enero 1994, J. Horton, Bolivia, Tarija, Arce, Quebrada Porcelana Bajo [into río Grande de Tarija], Porcelano Bajo, 22° 45' 30" S, 64° 18' 00" W). The corresponding lot could not be located in the collection and the occurrence of this Amazonian species so far south as the río Bermejo could therefore not be verified.

Terrazas Urquidi (1970) listed Apistogramma taeniatum (= A. taeniata) and Aequidens tetramerus for the Bolivian part of the río Paraguay drainage, but did not provide any further information about specimens. According to Kullander (2003), the former species is restricted to the lower río Tapajós drainage in Brazil (Amazon basin). Aequidens tetramerus s.l. occurs in the upper río Madera (Kullander 1986, Hablützel & Pantel 2017), but has - to our knowledge — not been reported from elsewhere in the La Plata drainage.

While the occurrence of Chaetobranchopsis australis is certain for the río Paraguay drainage in Bolivia, the report of related Chaetobranchus sp. from the río Bermejo drainage (Sarmiento et al. 2019) could not be verified. We have no knowledge of the possible introduction of this Amazonian genus in the río Paraguay drainage and therefore think this report should be considered questionable.

Identification issues

Discrimination between Cichlasoma boliviensis and Cichlasoma dimerus was based on sampling location, rather than diagnostic morphological traits. Subadults and adults of the former species typically (but not always) show a specific pattern of spots on the posterioventral portion of the flanks, giving them a mottled appearance. This colouration has never been reported from the La Plata basin, even though a large number of specimens have been screened. It appears reasonable to assume that the two species are allopatric and the watershed corresponds to the distribution boundary. However, it is clear that more taxonomic investigation should be done to know whether these species are, in fact, morphologically distinguished, or not.

Juveniles that do not show the diagnostic characters of their respective species were only identified at genus level. This applies in particular to species of the genus Apistogramma, which might be impossible to distinguish morphologically at juvenile stages.

The taxonomic status of Crenicichla ocellata

Crenicichla ocellata (Perugia, 1897) has been reported for the Bolivian part of the La Plata basin by Terrazas Urquidi (1970). This name, has been considered a synonym of C. semifasciata by several taxonomists (Ploeg 1991, Kullander 2003, Varella 2011). The Catalog of Fishes (Fricke et al. 2019), however, lists C. ocellata as a valid species with reference to several recent taxonomic studies. These publications, however, do not treat C. ocellata in the main text, but merely list the holotype among the examined material (e.g. Piálek et al. 2010, 2015, Casciotta et al. 2013, Říčan et al. 2017). In one publication, these authors list C. ocellata under its original name Boggiania ocellata (Piálek et al. 2010), indicating that the authors did not intend to recognize B. ocellata as a distinct species, but used its original name to indicate the holotype. However, other researchers subsequently started to list C. ocellata as a valid species (Koerber et al. 2017). Because no argument for or against the synonymy of B. ocellata in C. semifasciata is provided in recent taxonomic studies, we follow the authors that treat this taxonomic question explicitly or implicitly (Ploeg 1991, Kullander 2003, Varella 2011) and continue to consider B. ocellata as a synonym of C. semifasciata.

Completeness of the list

The introduced Amazonian Cichla piquiti has first been reported from the río Paraguay drainage in Bolivia by Sarmiento et al. (2014). Marques & Resende (2005) reported on Cichla cf. monoculus just north of Corumbá, a Brazilian city close to the Bolivian border. According to Kullander & Ferreira (2006) this introduced population belongs to Cichla piquiti. The occurrence of this species in Bolivia therefore appears possible, but unfortunately, no Bolivian specimens were accessible for examination.

Survey of the fish species in the Brazilian part of the Pantanal resulted in a cichlid species list that is almost identical to the one presented here (Menezes et al. 2000, Marcelino Polaz et al. 2014). Only Bujurquina oenolaemus, which is endemic to the río Aguas Calientes in Bolivia, was not recorded from Brazil. Menezes et al. (2000) and Varella (2011) reported on additional undescribed species of Crenicichla, whose distribution, however, may be restricted to the headwaters of the Río Paraguai in Brazil. In 2018, one species was formally described as Crenicichla ploegi Varella, Loeb, Lima & Kullander, 2018 (Varella et al. 2018).

Our rarefaction analysis shows that the curve is flattening out (Fig. 9), indicating that a large sampling effort has to be conducted to find additional species. Integrative taxonomic studies including genetic and non-traditional phenotypic characters as well as unconventional sampling techniques might still lead to the discovery of new species in the study area. While we did not quantify sampling effort, it appears that the Bermejo and Pilcomayo drainages are undersampled in comparison with the upper río Paraguay basin. Increased sampling effort will likely yield additional species for the former drainages. We nevertheless conclude that this species list for the Bolivian La Plata basin as a whole provides a sound basis for species identification, biodiversity inventories and ecological studies.

Conclusions

We report the occurrence of 17 species of cichlids in the Bolivian part of the La Plata drainage. Of those, 16 are documented with voucher specimens. The presence of the 17^th species (Cichla piquiti) appears plausible due to multiple reports of this introduced species in neighbouring areas in Brazil. Our rarefaction analysis supports the notion that sampling was exhaustive and that this species list is complete or at least almost complete. The diagnostic characters mentioned in the text and the dichotomous key should enable reliable identification of cichlids from the study area.

Acknowledgements

References

Carvajal-Vallejos, F.M., R. Bigorne, A.J. Zeballos Fernández, J. Sarmiento, S. Barrera, T. Yunoki, M. Pouilly, J. Zubieta, E. De La Barra, M. Jegú, M. Maldonado, P. Van Damme, R. Céspedes & T. Oberdorff. 2014. Fish-AMAZBOL: A database on freshwater fishes of the Bolivian Amazon. Hydrobiologia 732: 19–27.

Casciotta, J.R., A.E. Almirón, D. Aichino, S.E. Gómez, P. Piálek & O. Říčan. 2013. Crenicichla taikyra (Teleostei: Cichlidae), a new species of pike cichlid from the middle río Paraná, Argentina. Zootaxa 3721: 379–386.

Eigenmann, C.H. 1911. The localities at which Mr. John D. Haseman made collections. Annals of the Carnegie Museum 7: 299–314.

Farell, M.E. & F. Cancino. 2007. Nota sobre la ictiofauna de las subcuencas Tucavaca y Aguas Calientes, Santa Cruz, Bolivia. Kempffiana 3: 6–17.

Fricke, R., W.N. Eschmeyer & R. van der Laan. 2018. Catalog of fishes: genera, species, references. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. Last accessed 29 December 2019.

Hablützel, P.I. & J.H. Pantel. 2017. Strong spatial turnover in cichlid fish assemblages in the upper río Madera (Amazon basin) despite the absence of hydrological barriers. Hydrobiologia 791: 221–235.

Haseman, J.D. 1911. An annotated catalog of the cichlid fishes collected by the expedition of the Carnegie Museum to central South America, 1907-10. Annals of the Carnegie Museum 7: 329–373.

Kullander, S.O. 1980. A taxonomical study of the genus Apistogramma Regan, with a revision of Brazlilian and Peruvian species (Teleostei: Percoidei: Cichlidae). Bonner Zoologische Monographien 14: 1-152.        [ Links ]

Kullander, S.O. 1981. Cichlid fishes from the la Plata Basin. Part 1. Collections from Paraguay in the Muséun d’Historie Naturelle de geneve. Revue Suisse de Zoologie 88: 675–692.

Kullander, S.O. 1982a. Cichlid fishes from the la Plata basin. Part III. The Crenicichla lepidota species group (Teleostei: Cichlidae). Revue Suisse de Zoologie 89: 627–661.

Kullander, S.O. 1982b. Cichlid fishes from the La Plata basin. Part 2. Apistogramma commbrae (Regan, 1906) (Teleostei: Cichlidae). Revue Suisse de Zoologie 89: 33–48.

Kullander, S.O. 1982c. Cichlid fishes from the La Plata basin. Part IV. Review of the Apistogramma species, with description of a new species (Teleostei, Cichlidae). Zoologica Scripta 11: 307–313.

Kullander, S.O. 1983. A revision of the South American cichlid genus Cichlasoma (Teleostei: Cichlidae). Naturhistorska Riksmuseet, Stockholm.        [ Links ]

Kullander, S.O. 1984. Cichlid Fishes from the La Plata Basin. Part V. Description of Aequidens plagiozonatus sp.n. (Teleostei, Cichlidae) from the Paraguay River System. Zoologica Scripta 13: 155–159.

Kullander, S.O. 1986. Cichlid fishes of the Amazon River drainage of Peru. Swedish Museum of Natural History, Stockholm.        [ Links ]

Kullander, S.O. 1987. Cichlid fishes from the La Plata Basin. Part 6. Description of a new Bujurquina species from Bolivia. Cybium 3rd Series, 11(2): 195-205.        [ Links ]

Kullander, S.O. 2003. Family Cichlidae (Cichlids). pp. 605-654. In: Reis, R.E., Kullander, S.O. & C.J. Ferraris (eds.) Check List of the Freshwater Fishes of South and Central America. EDIPUCRS, Porto Alegrel.

Kullander, S.O. & E.J.G. Ferreira. 2006. A review of the South American cichlid genus Cichla, with descriptions of nine new species (Teleostei: Cichlidae). Ichthyological Exploration of Freshwaters, 17(4): 289-398.

Kullander, S.O. & A.M.C. Silfvergrip. 1991. Review of the South American cichlid genus Mesonauta Günther (Teleostei, Cichlidae) with descriptions of two new species. Revue Suisse de Zoologie 98: 407–448.

Lehner, B., K. Verdin & A. Jarvis. 2008. New global hydrography derived from spaceborne elevation data. Eos, Transactions 89(10): 93-94. Data is available at www.hydrosheds.org.

Marcelino Polaz, C.N., B.F. Melo, R. Britzke, E. Kawakami de Resende, F. de Arruda Machado, J.A. Ferraz de Lima & M. Petrere Jr. 2014. Fishes from the Parque Nacional do Pantanal Matogrossense, upper Paraguay River basin, Brazil. Check List 10: 122–130.

Marques, D.K.S. & E.K. Resende. 2005. Distribuição do Tucunaré Cichla cf. monoculus (Osteichthyes, Cichlidae) no Pantanal. Boletim de Pesquisa e Desenvolvimento, Embrapa Pantanal 60: 1–24.

Menezes, N., O. Froehlich, O. Oxakawa, P.W. Willink, A. Machado-Allison & B. Chernoff. 2000. Fishes collected and species new to science for each region sampled by the AquaRAP expeition to the Pantanal, Mato Grosso do Sul, Brasil, from August 25 to September 9, 1998. pp. 291-296. In: Willink, P. W., Chernoff, B., Alonso, L. E., Montambault, J. R. & R. Lourival (eds.) A Biological Assessment of the Aquatic Ecosystems of the Pantanal, Mato Grosso do Sul, Brasil. Conservation International, Washington DC.

Oksanen, J., R. Kindt, P. Legendre, R.B. O’Hara & M.H.H. Stevens. 2007. Vegan: Community Ecology Package. R package version 1.8-8. http://r-forge.rproject.org/projects/vegan.

Olden, J.D., M.J. Kennard, F. Leprineur, P.A. Tedesco, K.O Winemiller & E. García-Berthou. 2010. Conservation biogeography of freshwater fishes: recent progress and future challenges. Diversity and Distributions 16(3): 496-513.

Ottoni, F.P. 2018. Update of diagnoses, information on distribution, species, and key for identification of Laetacara species (Teleostei, Cichlidae, Cichlasomatini). Vertebrate Zoology 68(1): 47-63.        [ Links ]

Ottoni, F.P. & W.J.E.M. Costa. 2009. Description of a new species of Laetacara Kullander, 1986 from central Brazil and re-description of Laetacara dorsigera (Heckel, 1840) (Labroidei: Cichlidae: Cichlasomatinae). Vertebrate Zoology 59: 41–48.

Piálek, L., K. Dragová, J.R. Casciotta, A.E. Almirón & O. Říčan. 2015. Discription of two new species of Crenicichla (Teleostei: Cichlidae) from the lower Iguazú River with a taxonomic reappraisal of C. iguassuensis, C. tesay and C. yaha. Historia Natural 5(2): 5–27.

Piálek, L., O. Říčan, J. Casciotta & A. Almirón. 2010. Crenicichla hu, a new species of cichlid fish (Teleostei: Cichlidae) from the Paraná basin in Misiones, Argentina. Zootaxa 2537: 33–46.

Ploeg, A. 1991. Revision of the South American cichlid genus Crenicichla Heckel, 1840, with descriptions of fifteen new species and considerations on species groups, phylogeny and biogeography (Pisces, Percifomes, Cichlidae). PhD Thesis, Universiteit van Amsterdam, Amsterdam.        [ Links ]

Říčan, O., A.E. Almirón & J.R. Casciotta. 2017. Rediscovery of Crenicichla yaha (Teleostei: Cichlidae). Ichthyological Contributions of PecesCriollos 50: 1–8.

Sarmiento, J. & S. Barrera. 1997. Observaciones preliminares sobre la ictiofauna de la vertiente oriental andina de Bolivia. Revista Boliviana de Ecología 2: 77–99.

Sarmiento, J. & S. Barrera. 2004. Fish. pp. 122–128. In: Ibisch, P. L. & G. Mérida (eds.) Biodiversity: the richness of Bolivia - State of knowledge and conservation. Ministry of Sustainable Development, Editorial FAN, Santa Cruz.

Sarmiento, J., S. Barrera & C. Farfán. 2019. Ictiofauna y pesquerías de la cuenca del río Bermejo en Bolivia. pp. 225–273. In: Van Damme, P. A., Baigún, C. R. M., Sarmiento, J. & Carvajal-Vallejos, F. M. (eds.) Peces y Pesquerías en las Cuencas Pilcomayo y Bermejo. Editorial INIA, Cochabamba.

Sarmiento, J., R. Bigorne, F.M. Carvajal-Vallejos, M. Maldonado, E. Leciak, & T. Oberdorff. 2014. Peces de Bolivia / Bolivian fishes. IRD-BioFresh (EU), Plural editores, La Paz.

Schindler, I. & W. Staeck. 1993. Killifische aus dem Flußsystem des Río Paraguay - 1. Pterolebias phasanius. Die Aquarien- und Terrarienzeitschrift DATZ 46: 35–39.

R Development Core Team. 2012. R: A language and environment for statistical computing. R Foundation for Statistical Computing.        [ Links ]

Terrazas Urquidi, W. 1970. Lista de peces bolivianos. Academía nacional de Ciencias de Bolivia, Publicación N° 24, La Paz.

Travassos, H. 1957. Sôbre o material ictiológico coletado na excursão às zonas das estradas de ferro noroeste do Brasil e Brasil-Bolívia, nos estados de São Paulo e de Mato Grosso, Brasil e Bolívia oriental. Publicações avulsas do Museo Nacional 20: 21–27.

Varella, H.R. 2011. Revisão taxonômica das espécies de Crenicichla Heckel das bacias dos rios Paraná e Paraguai (Teleostei: Cichlidae). PhD Thesis, Universidade de São Paulo, São Paulo.        [ Links ]

Varella, H.R., M.V. Loeb, F.C.T. Lima, & S.O. Kullander. 2018. Crenicichla ploegi, a new species of pike-cichlid of the C. saxatilis group from the Río Juruena and upper Río Paraguai basins in Brazil, with an updated diagnosis and biogeographical comments on the group (Teleostei: Cichlidae). Zootaxa 4377: 361–386.