A new species of Peckoltia from the Upper Orinoco (Siluriformes, Loricariidae)

Abstract

A new species of the suckermouth armored catfish genus Peckoltia is described from the lower Ventuari River, a tributary of the upper Orinoco River in Amazonas State, Venezuela. Specimens of this species were formerly included in the wide-ranging Amazonian species Peckoltia vittata, but a recent molecular phylogeny found Orinoco individuals to be distantly related to Amazon Basin individuals spanning the range of Peckoltia vittata syntypes. Detailed morphological examination confirmed distinctiveness of Orinoco specimens, and found them to be diagnosable from true Peckoltia vittata by having generally greater than 25 teeth (vs. less), spots on the nape (vs. nape lacking spots), the upper lip with two to three black bar-shaped markings in a line like a moustache (vs. lips generally with a hyaline wash), and by the snout having a medial black line disconnected from the moustache markings (vs. medial snout stripe connected to a bar just above the lip). Peckoltia wernekei displays remarkable genetic similarity to its sister species, Peckoltia lujani, but differs morphologically by having dentary tooth rows meet at an angle less than 90° (vs. >90°), by having large faint blotches on the abdomen (vs. abdomen with no blotches), by a smaller internares width (21.2–26.6% vs. 28.5–46.5% of interorbital width), and a larger dorsal spine (148.1–178.6% vs. 80.1–134.5% of abdominal length).

Comparative Cytogenetics Analysis Among Peckoltia Species (Siluriformes, Loricariidae): Insights on Karyotype Evolution and Biogeography in the Amazon Region

“…The Loricariidae is one of the most specious family of catfish within the order Siluriformes, containing 1,016 valid species (Fricke et al, 2021). They are endemic to the Neotropical region, distributed throughout South America and part of Central America, and occur in a great diversity of habitats (Armbruster, 2004;Armbruster, 2008;Armbruster and Lujan, 2016). Analyzes based on morphological and molecular data support the recognition of six subfamilies: Lithogeninae, Delturinae, Hypoptopomatinae, Neoplecostominae, Loricariinae, and Hypostominae grouped in the tribes: Corymbophanini, Rhinelepini, Hypostomini, Pterygoplichthyini and Ancistrini (Armbruster, 2004;Lujan et al, 2015).…”

“…Peckoltia Miranda Ribeiro, 1912(sensu Lujan et al, 2015, comprises 18 valid species, in addition to distinct morphotypes that still lack description in the scientific literature. They are widely distributed in the Amazon and Orinoco basins and the Guiana Shield (Armbruster et al, 2015;Lujan et al, 2015;Armbruster and Lujan, 2016). According to phylogenetic analyzes proposed for Loricariidae, Peckoltia genus receive strong support as monophyletic lineage (Lujan et al, 2015;Lujan et al, 2017;Roxo et al, 2019); however, a complex taxonomic identification procedure at a specific level related to a wide geographic distribution and morphological similarity is observed for these species (Armbruster et al, 2015;Armbruster and Lujan, 2016).…”

“…They are widely distributed in the Amazon and Orinoco basins and the Guiana Shield (Armbruster et al, 2015;Lujan et al, 2015;Armbruster and Lujan, 2016). According to phylogenetic analyzes proposed for Loricariidae, Peckoltia genus receive strong support as monophyletic lineage (Lujan et al, 2015;Lujan et al, 2017;Roxo et al, 2019); however, a complex taxonomic identification procedure at a specific level related to a wide geographic distribution and morphological similarity is observed for these species (Armbruster et al, 2015;Armbruster and Lujan, 2016). For example, representatives of Peckoltia vittate (the type species of the genus) collected in the Amazon region (Xingu, Madeira and Orinoco rivers) presented polyphyletic lineages in molecular phylogeny by Lujan et al (2015).…”

“…For example, representatives of Peckoltia vittate (the type species of the genus) collected in the Amazon region (Xingu, Madeira and Orinoco rivers) presented polyphyletic lineages in molecular phylogeny by Lujan et al (2015). Armbruster and Lujan (2016), analyzed morphological and molecular characters of samples collected in the Orinoco basin associated with P. vittate by Lujan et al (2015) and described a new species, Peckoltia wernekei. These recent analyses agree that the diversity of Peckoltia species can be underestimated for the Amazon region.…”

Ammoglanis natgeorum, a new miniature pencil catfish (Siluriformes: Trichomycteridae) from the lower Atabapo River, Amazonas, Venezuela

“…Moreover, at least 10 other loricariid species occur only upstream of the confluence, despite the overall similarity in physical habitat throughout the main channel of the Orinoco upstream of the Raudales Atures ( e.g ., Baryancistrus beggini Lujan, Arce & Armbruster 2009, Baryancistrus demantoides Werneke, Sabaj Pérez, Lujan & Armbruster 2005, Hypancistrus contradens Armbruster, Lujan & Taphorn 2007, Hypancistrus vandragti (Lujan & Armbruster 2011), Lasiancistrus schomburgkii (Günther 1864), Leporacanthicus cf. galaxias , Leporacanthicus triactis Isbrücker, Nijssen & Nico 1992, Peckoltia lineola Armbruster 2008, Pseudancistrus pectegenitor Lujan, Armbruster & Sabaj Pérez 2007 and Pseudancistrus sidereus Armbruster 2004; Armbruster, 2005; Werneke et al ., 2005; Armbruster et al ., 2007; Armbruster, 2008; Lujan et al ., 2009; Lujan & Armbruster, 2011; Armbruster et al ., 2015; Armbruster & Lujan, 2016). A similar pattern of turnover in fish community composition has also been demonstrated in the Casiquiare Canal, approximately 200 km southeast of the confluence of the Guaviare, Atabapo, and Orinoco Rivers (Winemiller et al ., 2008).…”