Hyphessobrycon scholzei Ahl, 1937

Lima, Flávio C. T., Rodríguez-Olarte, Douglas & García-Alzate, Carlos A., 2025, A tale of false origins: Hyphessobrycon scholzei Ahl, 1937 and its junior synonym, Hyphessobrycon fernandezi Fernández-Yépez, 1972 (Teleostei: Characifomes: Acestrorhamphidae), Zootaxa 5594 (1), pp. 50-60 : 52-55

Hyphessobrycon scholzei Ahl, 1937

( Figs. 1–4 )

Hyphessobrycon scholzei Ahl, 1937: 445–446 (original description; type-locality: “ Amazonas bei Para ”); Géry, 1966: 66–70 (diagnosis in key, photo in life); Géry, 1977: 475, 480 (diagnosis in key, photo in life); Zarske & Géry, 1995: 115–116 (comments on the type series; lectotype designation); Zarske, 2015: 289 (photo in life).

Hyphessobrycon fernandezi Fernández-Yépez, 1972: 20 , pl. 20 (original description; type-locality “Río Yaracuy ”, Venezuela); Rodríguez-Olarte et al., 2006: 102, 109, 112, 115 ( Venezuela, río Tocuyo basin; common name, abundance, distribution); Rodríguez-Olarte et al., 2007: 43, 49 ( Venezuela, río Tocuyo basin; common name, abundance, distribution); García-Alzate et al., 2008: 141–142, 145–149 (redescription; designation of neotype; new type-locality “ Venezuela, Quebrada Cupa, finca de Víctor Atria, Cerca a Aroa en la vía a Duaca, 10º29’50’’N, 68º52’20’’W, Yaracuy ”); Rodríguez-Olarte et al., 2009: 74 (Tocuyo-Yaracuy and Tuy-Valencia hydrographic subprovinces, northern Venezuela); García-Alzate et al., 2010: 801–809 (morphogeometry); Rodríguez-Olarte et al., 2019: 601, 603–604 (length-weight relationship).

(not Bogotá-Gregory & Maldonado-Ocampo, 2006: 68; Maldonado-Ocampo et al., 2008: 169; Dagosta & de Pinna, 2019: 82).

Diagnosis. Hyphessobrycon scholzei can be diagnosed from all congeners, except from H. cachimbensis Travassos , H. citrus Marinho & Dagosta , H. chiribiquete García-Alzate , Lima, Taphorn, Mojica, Urbano-Bonilla & Teixeira, H. cyanotaenia Zarske & Géry , H. melanostichos Bertaco & Carvalho , H. nigricinctus Zarske & Géry , H. paucilepis García-Alzate, Román-Valencia & Taphorn , H. petricolus Ohara , Lima & Barros, H. piranga Camelier, Dagosta & Marinho , H. psittacus Dagosta, Marinho, Camelier & Lima, H. sovichthys Schultz , H. stegemanni Géry , H. taphorni García-Alzate, Román-Valencia & Ortega , H. tuyensis García-Alzate, Román-Valencia & Taphorn , and H. vilmae Géry , by presenting a well-defined dark midlateral stripe extending from immediately after the head to the caudal peduncle (vs. absence of a well-defined midlateral dark stripe extending into the caudal peduncle in the remaining congeners). Hyphessobrycon scholzei can be diagnosed from all aforementioned species by presenting a broad dark blotch at the caudal peduncle terminus and basal to middle portion of the caudal fin ( Fig. 3A ) (vs. dark pigmentation on caudal fin, when present, limited to an extension of the midlateral stripe, never forming a broad blotch; Fig. 3B–D ). Hyphessobrycon scholzei can be additionally diagnosed from H. cachimbensis , H. chiribiquete , H. citrus , H. cyanotaenia , H. melanostichos , H. nigricinctus , and H. petricolus by lacking a humeral blotch (vs. presence of a vertical humeral blotch overlapping with the anterior portion of the midlateral stripe in the aforementioned species; Fig. 3C–D ). See the item “Remarks”, below, for additional comments on the diagnosis of the species.

Distribution. Hyphessobrycon scholzei is only known from northern Venezuela, where it is distributed from small coastal river systems at the border between Falcon and Lara states, to the west, eastward into the río Sanchon basin, Carabobo state (areas 14, 15, 17, 18, 19, and 20 from Rodríguez-Olarte et al., 2009). Hyphessobrycon scholzei is additionally recorded from a tributary of the río Orinoco, the río Portuguesa, Portuguesa state ( Fig. 4 ). Records for the species from Suriname, and from the Amazon basin in Brazil and Colombia are incorrect and based either on mislabeled specimens or misidentifications (see Discussion, below).

Conservation status and habitat. Hyphessobrycon scholzei is considered “Vulnerable” according to the IUCN Red List of Threatened Species ( Rodríguez-Olarte et al., 2021, as H. fernandezi ). Across its distributional range, various environmental stressors associated with the expansion of the urban and agricultural frontiers are found, as deforestation, sewage disposal, and channel modification. The species is relatively eurytopic, occurring in streams and lagoons, and to some extent seems to be adaptable to habitat modification, as it can occupy reservoirs and artificial ponds ( Rodríguez-Olarte et al., 2021). However, urban, and industrial effluents are also discharged in reservoirs, which additionally are impacted by the presence of exotic, invasive species ( Oreochromis sp. ), water abstraction, and siltation ( Rodríguez-Olarte et al., 2021), Additionally, populations of H. scholzei are fragmented because the species has small, isolated populations in different coastal drainages. The species is reported for some protected areas, both in piedmont and coastal areas, but there are no protected areas across the intervening plains where the bulk of the distribution of the species lies ( Rodríguez-Olarte et al., 2021). It is important to notice, however, that the evaluation done by Rodríguez-Olarte et al. (2021) did not consider the occurrence of the species in the río Portuguesa basin nor in the coastal river systems at the border between Falcon and Lara states, and the conservation assessment of the species may change once a reevaluation considering the actual broader distributional range of the species is done.

Remarks. The comparison between preserved specimens of Hyphessobrycon scholzei from the aquarium trade [CAS(SU) 39870; MHNG 2177.080; MHNG 2177.081] with specimens of H. fernandezi collected in the wild [CAS(SU) 59483; CAS(SU) 59486; MZUSP 105445] revealed no differences in color pattern, meristic or morphometric data (see Tables 1–2 ). In addition, the comparison of several pictures of aquarium specimens of Hyphessobrycon scholzei with preserved specimens of H. fernandezi showed that they share a unique color pattern in the genus, i.e., the combination of a well-developed midlateral stripe extending into the caudal peduncle and a large dark blotch at the caudal peduncle terminus and basal to middle portion of the caudal fin. Additionally, both nominal species present the midlateral stripe narrowing at the caudal peduncle, which is slightly clear overall than the rest of the body (compare Figs. 1A–B ). Although several species of Hyphessobrycon present a midlateral stripe narrowing at the caudal peduncle, none of them possess a caudal peduncle which is overall clearer than the rest of the body. We conclude that both nominal species are synonymous, and that the valid name for the taxon is Hyphessobrycon scholzei , with H. fernandezi being relegated to its synonym. García-Alzate et al. (2008: 145) mentioned in the diagnosis of the species (as H. fernandezi ) some diagnostic features that were not confirmed in the material studied in the present paper (unfortunately much of the material used in that study was not available for examination in the present study). Three of the diagnostic characters for the species suggested in that study (number of branched dorsal-fin rays, number of branched pectoral-fin rays, and number of teeth in the inner row of the premaxilla) were herein found to be more variable (see Table 2 ) and consequently cannot be used as diagnostic features for H. scholzei . However, as mentioned in the “Diagnosis”, above, the color pattern of Hyphessobrycon scholzei is unique within the genus and consequently allows an unequivocal diagnosis of the species among congeners.

Material examined. Venezuela: MZUSP 105445 (28, 9.5–23.0 mm SL, 1 CS, 17.0 mm SL): Falcón, Tucacas, lagoon near Tucacas , 10º45'45''N, 68º19'37''W; C.A. Figueiredo, F. Breden & H. Brook, 12 May 2000. CAS ( SU) 59483 (1, 27.5 mm SL); CAS ( SU) 59486 (1, 25.9 mm SL): Venezuela (no other data). No locality/incorrect locality (aquarium specimens): CAS ( SU) 39870 (2, 31.5–34.4 mm SL): aquarium specimens; leg. O.C. Beldt. MHNG 2177.080 (1, 30.6 mm SL): " Paramaribo , environ Paramaribo; coll. Blijdorp. Exped. March 1952 "; MHNG 2177.081 (1, 32.7 mm SL): aquarium; leg. J.J. Scheel, 30 Sept 1970 .

Figures

FIGURE 1. Living specimens of Hyphessobrycon scholzei. (A) Aquarium specimens photographed in Germany, circa 2002 (photo by Hans-Georg Evers); (B) Venezuela, Yaracuy state, floodplain lagoon of the río Aroa, Palma Sola (photo by Douglas Rodríguez-Olarte).

FIGURE 2. Preserved specimens of Hyphessobrycon scholzei. All from Venezuela. (A) MBUCV–V 34105, 26.6 mm SL: Yaracuy, río Yaracuy; neotype of Hyphessobrycon fernandezi Fernandez-Yépez. (B) MCNG 52207, 44.9 mm SL: Portuguesa, río Portuguesa drainage. (C) MCNG 52216, 33.1 mm SL, Portuguesa, río Portuguesa drainage (photos by Carlos A. García- Alzate).

FIGURE 3. Schematic representation showing the main color patterns among Hyphessobrycon species presenting a dark midlateral stripe. (A) H. scholzei; (B) H. sovichthys; (C) H. chiribiquete; and (D) H. cyanotaenia.

FIGURE 4. Map of Northern South America showing the distribution of Hyphessobrycon scholzei (red dots; blue star indicates type-locality of H. fernandezi, junior synonym of H. scholzei).