Serrasalmus nalseni

Serrasalmus nalseni photo above is the first live in color photo of this species. Ivan Mikolji, a Venezuelan fish collector is hereby credited to have recaptured this specimen. Aside from the photo above, Ivan also took underwater videos of its natural habitat.

At the present time the fish is considered to be a member of genus Serrasalmus. Its body markings are similar to other species known as; S. eigenmanni, S. humeralis, S. aureus, S. hollandi, and S. serrulatus. However, there are differences in body shape, not known if this may be related to its ecology or geographical variation. There has not been further review of the species since 1996 (see below). With the presentation of the live colors Antonio Machado-Allison (Universidad Central de Venezuela) will be is revisiting this species. This poorly described species is in dire need of a makeover. So more will be forthcoming in the future.

May 22, 2010 - A new revised descrption of S. nalseni is now published. I will adding changes to this page over the next few days which will incorporate the neo-type and its new description from the holotype specimen material which was lost. The neotype has been deposited in the fish collection of the Museo de Biologia of the Universidad Central de Venezuela along with several topotypes (Machado-Allison et al 2009).

Resumen. Se presenta la redescripción de Serrasalmus nalseni Fernández-Yépez, 1969 basada en la captura de nuevos ejemplares provenientes de la localidad tipo. Se incorpora información morfométrica y merística que permite diagnosticar y describir con mayor detalle esta especie, incluyendo patrón de coloración en vivo. Dado la imposibilidad de obtener localización y acceso al material tipo, se incorpora la designación de un neotipo y varios topotipos los cuales se depositan en la Colección de Peces del Museo de Biología de la Universidad Central de Venezuela. Palabras clave. Serrasalmus nalseni. Serrasalmidae. Descripción. Neotipo. Designation of a neotype a redescription of Serrasalmus nalseni Fernández-Yépez, 1969 (Characiformes, Serrasalmidae)

Abstract. We present a redescription of Serrasalmus nalseni Fernández-Yépez, 1969, based on new specimens from the type locality. We include new morphometric and meristic data that allows us to thoroughly diagnose and describe this species, including its live color pattern. Because all type material is lost, we designate a neotype which has been deposited in the fish collection of the Museo de Biología of the Universidad Central de Venezuela along with several topotypes. Considered a rare species. Description by Fernández-Yépez, 1969

Characteristics: Compressed body, high-backed; pre-dorsal spine; pointy snouted; ectopterygoid teeth present usually 4 to 5. Moderate eye diameter. Dorsal fin moderate with 13-14 rays. Adipose fin base is small. Large caudal fin.

Vertebrate 37-38, usually 38. Numerous small scales. Lateral line 80. Prepelvic serrae 24-25, postpelvic 8-10. Branched spines short and the base wide, 23-24.

Map shows locality

Drawing by famed ichthyologist Agustin Fernandez-YepezThe Piranha Book page 120.

Photo courtesy of Dr. Antonio Machado-Allison

Like other species described by Fernández-Yépez, it is impossible to determine the type locality where the species was collected. In Fernández-Yépez description, the author discusses that this species is very close appearing to S. rhombeus. He differentiates S. nalseni by it having a wide basal caudal band, banda caudal basal y ancha. The author, in another part indicates that the body of S. nalseni is higher backed.

It should be noted this description was based on two examples collected and examined by Machado-Allison and Fink. This has permitted them to partially reassess the species. In keeping with the original written description, this species is easily confused for S. rhombeus, except for the color which is like S. irritans. This last one is distinguished by the form of the body, which is much more high backed in S. nalseni.

(The species has since been found and re-described): The species can be found where it was previously described from the rios Uracoa and Morichal Largo, this species is preliminarily accepted until more are captured.

Color of Life: The body of this species is metallic green with numerous dark spots , some of them larger than the diameter of the eye. Diffused humeral spot. The fins are dark. The caudal fin has a wide basal band. Distally, the fin is hyaline with some pigmentation. Base of the adipose is dark.

Color in alcohol: Preserved examples show dark pigmentation. The dark spotting is much evident. A dark band shows over the base of the anal fin rays (band of scales). The caudal band is very prominent. The humeral spot presents itself diffused.

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