Systematics of Lamontichthys Miranda-Ribeiro (Siluriformes: Loricariidae), with the description of two new species

Abstract

The taxonomic revision of the genus Lamontichthys Miranda-Ribeiro, based on the examination of 164 specimens of different river drainages throughout the Amazon basin, revealed the presence of six species of which two are new. Lamontichthys filamentosus occurs in the upper and middle portions of the rio Amazonas basin; L. llanero in the río Orinoco basin; L. maracaibero in the lago Maracaibo basin; and L. stibaros in the upper río Amazonas basin. Lamontichthys avacanoeiro, new species, occurs in the upper rio Tocantins basin; and L. parakana, new species, in the lower rio Tocantins basin. The new species represent a considerable extension in the so far known distribution of the genus. A parsimony analysis, including 87 osteological and external morphological characters from Lamontichthys and related taxa (total of 16), resulted in three most parsimonious trees with 194 steps (CI = 0.73 and RI = 0.78). The hypothesis of monophyly of Lamontichthys is corroborated and supported by six derived characters. Within Lamontichthys two monophyletic assemblages are recognized, one includes L. avacanoeiro and L. stibaros, the other includes L. maracaibero and the clade formed by L. filamentosus and L. llanero. The relationships of Lamontichthys parakana, a species that was not included in the phylogenetic analysis is discussed. The monophyly and relationships of the monotypic genus Pterosturisoma microps are also discussed.<br>A revisão taxonômica do gênero Lamontichthys, realizada com base no exame de 164 exemplares de diversas drenagens da bacia amazônica, revelou a existência de seis espécies, das quais duas são novas. Lamontichthys filamentosus ocorre na bacia do alto e médio rio Amazonas; L. llanero, na bacia do rio Orinoco; L. maracaibero, na bacia do lago Maracaibo; e L. stibaros, na bacia do alto rio Amazonas. Lamontichthys avacanoeiro, espécie nova, ocorre na bacia do alto rio Tocantins e L. parakana, espécie nova, na bacia do baixo rio Tocantins. As novas espécies representam uma considerável ampliação da distribuição geográfica do gênero. Uma análise de parcimônia, incluindo 87 caracteres osteológicos e de morfologia externa de 16 táxons, incluindo Lamontichthys e grupos relacionados, resultou em três cladogramas mais parcimoniosos com 194 passos (CI = 0.73 and RI = 0.78). A hipótese de monofiletismo de Lamontichthys é corroborada e sustentada por seis sinapomorfias. Entre as espécies de Lamontichthys, dois grupos monofiléticos são reconhecidos, um incluindo L. avacanoeiro e L. stibaros e outro L. maracaibero e um clado formado por L. filamentosus e L. llanero. A relação de Lamontichthys parakana com as demais espécies do gênero é discutida, apesar da espécie não ter sido incluída na análise filogenética. O monofiletismo e as relações do gênero monotípico Pterosturisoma microps são também discutidos

A new species of Farlowella (Siluriformes: Loricariidae) of the F. nattereri species-group from the rio Xingu basin, Mato Grosso, Brazil, with comments on Farlowella jauruensis , a poorly-known species from the upper rio Paraguai basin

“…Terminology, meristics and measurements follow Boeseman (1971Boeseman ( , 1976, Retzer & Page (1996), Schaefer (1997), and Paixão & Toledo-Piza (2009); osteological terminology follows Geerinckx et al (2007). Lateral plate series in Farlowella show variation in the fusion between the dorsomedian and median plate series, exhibiting four series when the plates are fused anteriorly, or five series when the anteriormost dorsomedian plates are free.…”

Taxonomic revision and phylogenetic relationships of Dasyloricaria Isbrücker & Nijssen, 1979 (Siluriformes: Loricariidae), with description of a new species

“…Institutional abbreviations follow Sabaj Pérez (2012). Osteological nomenclature follows Schaefer (1987), Rapp Py-Daniel (1997 and Paixão & Toledo-Piza (2009). Specimens for osteological observations were cleared and counterstained for bone and cartilage using the method of Taylor & Van Dyke (1985).…”

“…The outgroup was chosen in order to test both the relationships in Dasyloricaria and among the genera previously included in Rineloricariina sensu Isbrücker. Characters described mainly by Rapp Py-Daniel (1997), Fichberg (2008), and Paixão & Toledo-Piza (2009) for different members of the Loricariinae were included in the analysis with additional characters proposed for the first time herein. The monophyly of Dasyloricaria, the phylogenetic relationships among its species, and the monophyly of the Rineloricariina were tested using the cladistic methodology proposed by Hennig (1966).…”

“…The heuristic search was performed with 1000 replications of Random Addition Sequence and branch swapping through the Tree Bisection Reconnection (TBR) algorithm, with additional TBR swapping to completion, on the unweighted and unordered data matrix. Cladograms were rooted on Harttia loricariformis according to previous phylogenies (Rapp Py-Daniel, 1997;Fichberg, 2008;Paixão & Toledo-Piza, 2009). Tree support was calculated in NONA as decay indices or Bremer support (Bremer, 1994).…”

“…Relative length of laminar expansion along the ventral border of anterohyal (Paixão & Toledo-Piza, 2009; Character 10, modified). Paixão & Toledo-Piza (2009) described three states for this character.…”