Loricaria cuffyi (Siluriformes: Loricariidae), a new species of loricariin catfish from the Guiana Shield

A new genus and species of whiptail armored catfish (Siluriformes: Loricariinae) from southern Venezuela

A new genus and species of whiptail loricariid catfish belonging to the Pseudohemiodon group is described with 12 specimens captured from the upper Orinoco River and Casiquiare River, Amazonas State, Venezuela. The specimens show delicate and fragile appearance, and are small (largest specimen 74.3 mm SL). The new species has external morphological characters that support its inclusion in the Pseudohemiodon group; however, its mouth morphology is distinctive and unique with features not observed in any species of that group, nor in any other species included in tribe Loricariini or in subfamily Loricariinae. The distinctive buccal characters include: 1) barblets on upper lip border and the maxillary barbel included and interconnected by translucent membrane, leaving the tips free; 2) lower lip surface covered with elongated, cylindrical, unbranched, and fleshy barblets, which resemble filaments, some of them surpassing the border of lower lip. The comparative analyses carried out determined that the recently described species Rhadinoloricaria papillosa has the same two diagnostic buccal characters observed in the new species; therefore it is transferred to the new genus.

A new species of Sturisoma Swainson, 1838 (Loricariidae: Loricariinae), from the Madeira River basin, with a discussion of historical biogeography of western Amazonas and Paraguay River basins

A new loricariin species of Sturisoma is described from the Cautário, Guaporé, Mamoré, Machado and Soteiro rivers, Madeira River basin, in Bolivia and Brazil. The new species is distinguished from its congeners by the presence of a middorsal longitudinal, thin dark brown stripe on the caudal peduncle, extending from two or three plates posterior to the dorsal-fin base, reaching the origin of the caudal fin, or one or two plates anterior to the origin of the caudal fin; small squarish anteriormost abdominal plates; and a middorsal longitudinal dark-brown stripe from first predorsal plate to near the dorsal-fin origin. Furthermore, the new species is diagnosed from congeners by plate morphology, counts on the median series, coalescent plates and ventrolateral thoracic plates, in addition to measurements related to body and head structures. An analysis of genetic distances using cytochrome C oxidase subunit 1 gene marker of the mitochondrial genome between the new species and several congeners is presented, in addition to a likelihood analysis to illustrate the position of the new taxon within Sturisoma. An identification key for species of the genus currently recorded at the upper Amazonas River basin is provided.

The distribution of Cteniloricaria (Siluriformes: Loricariidae): known and new records in Brazil suggest headwater captures as drivers of disjoint distribution

Abstract Cteniloricaria is a genus of Neotropical armored catfishes belonging to the Loricariinae, currently including two valid species: C. platystoma and C. napova. Cteniloricaria platystoma is presently recorded across the main coastal drainages of the Guiana Shield, from the Sinnamary River, French Guiana, to the Essequibo River basin, Guyana, and is considered to be restricted to the region. Cteniloricaria napova is only known from its type locality at the headwaters of the Paru de Oeste River, Amazon basin, Sipaliwini Savannah, Trio Amerindian territory in Suriname, close to the Brazilian border. Based on a specimen of C. napova, captured in the Cuminapanema River, a tributary to the Curuá River, within Brazilian territory, the geographic distribution of the species and the genus is extended, representing the first record of Cteniloricaria in Brazil. The genus shows a disjoint distribution, and divergence between populations in the north-flowing coastal rivers of the Guianas and the south-flowing Amazon tributaries, and more recent headwater capture between south-flowing Amazon tributaries, may have played a key role in shaping its current distribution. Illustrations, diagnostic characters, morphometrics, description of the habitat where the new specimen was captured, extinction risk assessment, and a discussion of the distribution of the genus are provided.