A New Basal Ancistrini Genus and Species from the Andes of Northern Peru (Siluriformes: Loricariidae)

Etsaputu relictum, a new genus and species sister to all other Ancistrini, is described from the upper Marañon River in Northern Peru. Etsaputu relictum can be diagnosed from all other Hypostominae by having a coracoid with a serrated posterior margin of the posterior process, an opercle with a process extending ventrolaterally from the ventral margin, and branchiostegals one and two fused. Etsaputu relictum is further distinguished by having cheek plates evertible to less than 45° from the sagittal plane, by having fewer than ten (typically zero or six) enlarged cheek-plate odontodes, by having enlarged cheek-plate odontodes straight and no longer than 15 times length of odontodes on lateral body plates, by having large eyes (mean 24.0% of head length, range 21.7–27.6% HL), and by having uniformly gold-brown to bronze base color with golden sheen when alive.

Fig. 1.

Posterior process of the coracoid of (A) Hypostomus cf. plecostomus, UF 77909, and (B) Etsaputu relictum, new genus, new species, AUM 45538. Left side, lateral view, anterior to left. Scale bars = 1 mm.

Fig. 2.

Opercles of (A) Hemiancistrus maracaiboensis, EBRG 2855, (B) Peckoltia furcata, FMNH 70863, (C) Etsaputu relictum, new genus, new species, AUM 45538, and (D) Ancistrus pirareta, UMMZ 206085 (illustrations A, B, and D from Armbruster, 2004). Right side, mesial view, anterior to left. Scale bars = 1 mm.

Fig. 3.

Branchiostegals 1–4 of (A) Chaetostoma pearsei, INHS 34589, and (B) Etsaputu relictum, new genus, new species, AUM 45538. Short, dashed line between distal end of branchiostegal 1 and branchiostegal 2 of Etsaputu relictum indicates the visible line of fusion between these elements. Left side, lateral view, anterior to left. Scale bars = 1 mm.

Fig. 4.

Holotype of Etsaputu relictum, new genus, new species, MUSM 32383, 87.3 mm SL, Peru, Amazonas Department, Marañon River drainage, gravel shoal at Tsantsa in the Cenepa River, 4°33′37″S, 78°11′07″W, N. K. Lujan, D. C. Werneke, D. C. Taphorn, K. A. Capps, D. P. German, and D. Osorio, 2 August 2006.

Fig. 5.

Known distribution of Etsaputu relictum in northern Peru: open circle indicates type locality (228 m asl), closed circles represent multiple paratype localities (170–258 m asl), circle with × represents localities of non-type material from the Huallaga River drainage (501–514 m asl).

Contributor Notes

Associate Editor: R. E. Reis.

¹ Department of Biological Sciences, Auburn University, 303 Funchess, Auburn, Alabama 36849; E-mail: (JWA) armbrjw@auburn.edu.

² Present address: Section of Ecology, Evolution and Systematic Biology, Department of Wildlife and Fisheries Sciences, Texas A&M University, 215 Old Heep Hall, 2258 TAMU, College Station, Texas 77843-2358; E-mail: nklujan@gmail.com. Send reprint requests to this address.

³ Environmental Directorate, The Americas Fund, Av. Primavera 1053, San Borja, Lima 41, Peru; Department of Ichthyology, Natural History Museum, University of San Marcos, Lima, Peru; E-mail: brengifo@fondoamericas.org.pe.

Received: 17 Dec 2010

Accepted: 01 Jul 2011