DARIO R. FAUSTINO-FUSTER, HERNÁN ORTEGA

Abstract

Mastiglanis is a genus of heptapterid catfish represented by two valid species. These freshwater species are widely distributed along the Amazon, Orinoco, and Maroni River basins. However, a taxonomic review of specimens collected in the Putumayo and Nanay rivers, Amazon River basin in Peru revealed a new species of Mastiglanis. A morphological analysis was completed for morphometric (36 measurements) and meristic (20 counts) data. Osteological counts and descriptions were made from clear and stained specimens and x-rays images. The new species of Mastiglanis differs from M. asopos and M. durantoni by having a long pelvic fin, short snout, eight branched anal-fin rays, and a higher number of vertebrae and gill rakers. The distribution of the new species is restricted to the upper Amazon River basin.

link: https://www.biotaxa.org/Zootaxa/article/view/zootaxa.4820.2.6

Figure 2. Dorsal view of cranium of Mastiglanis yaguas, paratype, MUSM 61686, 42.7 mm SL. Abbreviations: af = anterior fontanel; ap = autopalatine; ep = epioccipital; ex = exoccipital; fr = frontal; le = lateral ethmoid; mx = maxilla; na = nasal; pf = posterior fontanel; pm = premaxilla; pt = pterotic; soc = supraoccipital; sp = sphenotic; tp4a = anterior branch of transverse process of vertebra 4; tp4b = posterior branch of transverse process of vertebra 4; tp5 = transverse process of vertebra 5 . Arrow = symphysial region of premaxilla.

Figure 1. Mastiglanis yaguas, new species, MUSM 66612, holotype, 49.1 mm SL, (A) Lateral view of right side (image flipped), (B) Dorsal view, (C) Ventral view. Bar = 1 cm.