Tuesday, April 18, 2017

[Ichthyology • 2017] Hyphessobrycon klausanni • A New Species of Hyphessobrycon (Characiformes, Characidae) from the upper Guaviare River, Orinoco River Basin, Colombia

Hyphessobrycon klausanni 
García-Alzate, Urbano-Bonilla & Taphorn, 2017 

Hyphessobrycon klausanni sp. n. is described from small drainages of the upper Guaviare River (Orinoco River Basin) in Colombia. It differs from all congeners by having a wide, conspicuous, dark lateral stripe extending from the anterior margin of the eye across the body and continued through the middle caudal-fin rays, and that covers (vertically) three or four horizontal scale rows. It also differs by having an orange-yellow stripe extending from the anterosuperior margin of the eye to the caudal peduncle above the lateral line in life. It differs from all other species of Hyphessobrycon that have a similar dark lateral stripe: H. cyanotaenia, H. loretoensis, H. melanostichos, H. nigricinctus, H. herbertaxelrodi, H. eschwartzae, H. montogoi, H. psittacus, H. metae, H. margitae, H. vanzolinii, and H. peruvianus in having only three or four pored scales in the lateral line, 21 to 24 lateral scales and six teeth in the inner premaxillary row. Hyphessobrycon klausanni differs from H. loretoensis in having seven to eight maxillary teeth (vs. three to four) and in having a longer caudal peduncle (12.4–17.0% SL vs. 4.6–8.0% SL). Additionally Hyphessobrycon klausanni can be distinguished from the other species of Hyphessobrycon with a dark lateral stripe from the Orinoco River Basin (H. metae and H. acaciae) in having two teeth in the outer premaxillary row (vs. three to four) and 10 branched pectoral–fin rays (vs. 11 to 12). It further differs from H. metae by the length of the snout (17.6–22.8% HL vs. 9.9–15.2% HL) and by the length of the caudal peduncle (12.4–17.0% SL vs. 7.3–11.8% SL).

Keywords: New taxon, Neotropical Ichthyology, Guaviare River, diversity

Figure 3. Live colours of Hyphessobrycon klausanni sp. n. Paratype, UARC–IC 540, 22.4 mm SL. 

Etymology: Research leading to the discovery and recognition of this species was partially funded by Mr. Klaus-Peter Lang from Oberhausen, Germany. To commemorate the 80th birthday of his mother, this species is dedicated to and named for his father “Klaus” and his mother “Anni”.

Ecological note: Hyphessobrycon klausanni lives in shallow (0.30–1.5 m) well-oxygenated (6.39–7.68 mg/l) streams with transparent waters flowing (0.063 m/s) over different types of substrates (rocks, sand, gravel and decomposing organic material). The temperature range was narrow, 25.5–26°C but pH varied from moderately acidic to basic (6.47–8.7). Hyphessobrycon klausanni was found near shore among aquatic vegetation, tree roots and fallen logs. Other species found at the sites included: Hemigrammus barrigonae, Ctenobrycon spilurus, Tyttocharax metae, Moenkhausia oligolepis, M. chrysargyrea, M. lepidura, Chrysobrycon guahibo, Ochmacanthus orinoco, Farlowella vittata, Ancistrus triradiatus, Centromochlus reticulatus and Anablepsoides sp. Stomach content analysis (n = 4) revealed a diet of aquatic and terrestrial invertebrates: Coleoptera (Dytiscidae), Ephemeroptera, Hymenoptera (Formicidae), larvae of Chironomidae and others not identified due to the degree of fragmentation.

Carlos A. García-Alzate, Alexander Urbano-Bonilla and Donald C. Taphorn. 2017. A New Species of Hyphessobrycon (Characiformes, Characidae) from the upper Guaviare River, Orinoco River Basin, Colombia. ZooKeys. 668; 123-138. DOI:  10.3897/zookeys.668.11489

Resumen: Hyphessobrycon klausanni sp. n. es descrita de pequeños drenajes del alto río Guaviare (cuenca del río Orinoco) en Colombia. Se diferencia de todos los congéneres por tener una amplia franja lateral oscura lateral que se extiende desde el margen anterior del ojo a través del cuerpo y se continúa hasta la base de la aleta caudal y que cubre (verticalmente) tres o cuatro escamas laterales, además difiere por tener una franja de color naranja-amarillo que se extiende desde el margen anterosuperior del ojo hasta el pedúnculo caudal por encima de la línea lateral en vida. Se diferencia de H. cyanotaenia, H. loretoensis, H. melanostichos, H. nigricinctus, H. herbertaxelrodi, H. eschwartzae, H. montogoi, H. psittacus, H. metae, H. margitae, H. vanzolinii, y H. peruvianus por tener solo 3 a 4 escamas con poros en la línea lateral, 21 a 24 escamas laterales y 6 dientes en la fila interna del premaxilar. Hyphessobrycon klausanni se diferencia de H. loretoensis por presentar 7 a 8 dientes maxilares (vs. 3 a 4) y la longitud del pedúnculo caudal (12.4–17.0% LE vs. 4.6–8.0% LE). Además se puede distinguir de las demás especies con banda lateral oscura presentes en la cuenca del rio Orinoco (H. metae y H. acaciae) por tener dos dientes en la fila externa del premaxilar (vs. 3 a 4) y 10 radios ramificados en la aleta pectoral (vs. 11 a 12), además se separa de H. metae por la longitud de hocico (17.6–22.8% LC vs. 9.9–15.2% LC) y por la longitud del pedúnculo caudal (12.4–17.0% LE vs. 7.3–11.8% LE).

Palabras clave: Nuevo taxón, Ictiología Neotropical, río Guaviare, diversidad

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