Redescription of Ancistrus greeni (Siluriformes: Loricariidae), and description of a new species from the río Madre de Dios basin, Peru

Abstract

A new species of Ancistrus is described from minor tributaries of the río Madre de Dios basin (Cusco - Madre de Dios - Puno), in Peru. The new species shares with A. greeni an uncommon unicusp dentition; but it is distinguished from A. greeni by a larger orbital diameter, deeper caudal peduncle, and larger adipose-fin spine. The redescription of A. greeni is provided, and its recognition along with the discovery of this new species increases to five the officially number of Ancistrus species from the río Madre de Dios basin. The lectotype and paralectotype of A. greeni are provided.

A new distinctively striped species of bushynose catfish (Siluriformes: Loricariidae: Ancistrus) from the Pachitea River drainage, Pasco, Peru

“…Most species of Ancistrus have mean orbital diameter (OD) >15% HL (i.e., de Souza et al, 2019; Taphorn et al, 2013), like A. yanesha (OD mean = 21.1% HL; Table 1). On the other hand, some Andean species have what we can consider as very small eyes, like A. greeni (Isbrücker, 2001) (OD mean = 11%; Bifi & Ortega, 2020) and A. occloi (OD =10.9% HL, CAS‐ICH 071818). Based on these features, we can distinguish A. yanesha from A. jelskii based on both coloration and morphological features.…”

“…Currently, only five other species reach similar sizes: A. maximus de Oliveira et al, 2015 is the largest species ever described, reaching more than 200 mm SL. The four other species are A. centrolepis Regan, 1913 and A. chagresi Eigenmann & Eigenmann, 1889 reaching 187.2 and 170.7 mm SL, respectively (Taphorn et al, 2013), A. alga (Cope, 1872), with 161 mm SL (Provenzano & Barriga, 2018), and two specimens of A. maldonadoi Bifi & Ortega, 2020, with 150 and 154 mm SL, deposited in the Auburn University Museum Fish Collection (AUM 51185).…”

“…All but A . maldonadoi Bifi & Ortega, 2020 and A . tamboensis Fowler, 1945a were described more than a century ago in a form that was brief and largely uninformative, complicating the recognition and delimitation of both valid and undescribed Ancistrus species in Peru.…”

“…The first of these characters is universal; however, four Ancistrus species have eight or nine branched dorsal-fin rays: A. dolichopterus Kner, 1854, A. fulvus (Holly, 1929), A. latifrons (Günther, 1869), and A. maximus de Currently, there are 12 valid Ancistrus species described from Peru, and four synonyms. All but A. maldonadoi Bifi &Ortega, 2020 andA. tamboensis Fowler, 1945a were described more than a century ago in a form that was brief and largely uninformative, complicating the recognition and delimitation of both valid and undescribed Ancistrus species in Peru.…”

Typupiscis lujanensis (Ameghino 1874), assignment to Ancistrus cirrhosus (Valenciennes 1836), the Ameghino-Burmeister rivalry and the beginning of the scientific photography in the Plata.

“…El género Ancistrus. Este género se distribuye desde Panamá hasta los ríos afluentes a la Río de la Plata (López et al, 1987(López et al, , 2003Miquelarena et al, 1994;Provenzano et al, 2018) y es uno de los géneros con más especies de los loricáridos (Bifi & Ortega, 2020). Hasta el momento se conocen cuatro especies en Argentina, en la cuenca del Paraná-Plata: Ancistrus cirrhosus, Ancistrus taúnayi, Ancistrus piriformis y A. mullerae (Koerber & Weber, 2014;Mirande & Koerber, 2015;Casciotta et al, 2016).…”