Editorial Type:
Article Category: Research Article
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Online Publication Date: 25 Sept 2015

A Multilocus Molecular Phylogeny for Chaetostoma Clade Genera and Species with a Review of Chaetostoma (Siluriformes: Loricariidae) from the Central Andes

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Page Range: 664 – 701
DOI: 10.1643/CI-14-194
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The rubbernose-pleco genus Chaetostoma comprises 47 currently valid and many undescribed species distributed along Atlantic and Pacific slopes of the Andes Mountains from Panama to southern Peru, the Coastal Mountains of Venezuela, and drainages of the Guiana and Brazilian shields. We present a five-locus molecular phylogeny for 21 described and six undescribed species of Chaetostoma spanning the geographic range of the genus. Bayesian and maximum likelihood analyses found Chaetostoma to be well supported as monophyletic and sister to a clade of central and northern Andean genera that have also been hypothesized to be closely related based on morphology (i.e., Andeancistrus, Cordylancistrus, Dolichancistrus, Leptoancistrus, and Transancistrus). Species of Chaetostoma were divided into a trichotomy consisting of: a Pacific Coast, Central American, Magdalena Basin, Lake Valencia, and Guiana Shield clade; a western Orinoco, Lake Maracaibo, and Lake Valencia clade; and a widespread upper Amazon/Orinoco clade inclusive of a single species on the Brazilian Shield. We also conducted a systematic review of species from the central Andes of northern Peru and Ecuador. Based on our phylogenetic results and direct examination of historical and recently collected type and non-type material, we describe two new species of Chaetostoma (C. bifurcum, from the Pacific Coast, and C. trimaculineum, from the Atlantic Slope), redescribe four species (C. breve, C. carrioni, C. dermorhynchum, and C. microps, all from the Atlantic Slope), transfer four species from Chaetostoma to Ancistrus and find two species to be junior synonyms.

Las carachamas nariz de goma del género Chaetostoma comprenden 47 especies válidas y algunas especies no descritas distribuidas a lo largo de las vertientes Atlántico y Pacífico de la Cordillera de los Andes desde Panamá hasta el sur de Perú, las montañas costeras de Venezuela, y cuencas de los escudos de Guayana y Brasil. Presentamos una filogenia molecular de cinco loci para 21 especies descritas y seis no descritas de Chaetostoma, que abarcan el área de distribución geográfica del género. Los análisis de probabilidad bayesiana y máxima verosimilitud muestran que Chaetostoma está bien soportado como grupo monofilético y grupo hermano del clado de los géneros andinos del centro y norte, que también se ha hipotetizado que están estrechamente relacionados en base a la morfología (p.e., Andeancistrus, Cordylancistrus, Dolichancistrus, Leptoancistrus y Transancistrus). Las especies de Chaetostoma se dividieron en una tricotomía que consiste en: un clado de la costa del Pacífico, Centroamérica, cuenca del Magdalena, Lago de Valencia y del Escudo Guayanés; un clado del oeste del Orinoco, Lago de Maracaibo y Lago de Valencia; y un clado ampliamente distribuido del alto Amazonas/Orinoco incluyendo la única especie en el Escudo Brasileño. Realizamos también una revisión sistemática de las especies de los Andes centrales del norte de Perú y Ecuador. Basados en nuestros resultados filogenéticos y en la examinación directa de colectas históricas y recientes de material tipo y no tipo, se describen dos nuevas especies de Chaetostoma (C. bifurcum, de la costa Pacífica y C. trimaculineum, de la vertiente del Atlántico), se redescriben cuatro especies (C. breve, C. carrioni, C. dermorhynchum, C. microps, todas de la vertiente del Atlántico), se transfieren cuatro especies de Chaetostoma a Ancistrus y se encuentran dos especies que son sinónimo junior.

Copyright: © 2015 by the American Society of Ichthyologists and Herpetologists
Fig. 1.
Fig. 1.

Illustrations of representative female (left) and male (right) urogenital pores of Chaetostoma. Illustrations by VAC.

Fig. 2.
Fig. 2.

Phylogenetic relationships within the Chaetostoma Clade (sensu Lujan et al., 2015) based on Bayesian analysis of a 4293 base pair alignment consisting of two mitochondrial (16S, Cyt b) and three nuclear loci (RAG1, RAG2, MyH6). Taxa from Pacific Coast drainages in blue and Brazilian or Guiana Shield drainages in green. Node numbers correspond to Bayesian posterior probability (BI) and maximum likelihood (ML) support values in Table 3. Numbers in red indicate indicate BI: <90; numbers in italics indicate ML: <50. Samples taken from at or near the type locality for a given species are indicated by asterisks and species that are types for the given genus are indicated by †.

Fig. 3.
Fig. 3.

Chaetostoma dermorhynchum from the Pastaza River drainage, Ecuador: (A) immature (type locality; ROM 93946, 84.4 mm SL) and (B) adult male (ROM 93656*, 171.7 cm SL). Scale bars  =  1 cm. Photos by NKL.

Fig. 4.
Fig. 4.

Chaetostoma breve from various drainages along the Atlantic Slope of the Andes: the (A, B) Napo (Ecuador: ROM 93950*, A: 117.4 mm, B: 137.1 mm SL), (C) Santiago (Ecuador: type locality; ROM 93848, 127.2 mm SL), and (D) Marañon (Peru: AUM 46515*, 91.5 mm SL) river drainages. Scale bars  =  1 cm. Photos by NKL.

Fig. 5.
Fig. 5.

Chaetostoma microps from various Atlantic Slope drainages of the Andes: the (A) Napo (Ecuador, ROM 93948, 72.3 mm SL), (B, C) Santiago (Ecuador, type locality; B: ROM 93902, 74.5 mm SL, C: ROM 93895*, 56.2 mm SL), and (D) Marañon (Peru, AUM 45525) river drainages. Scale bars  =  1 cm. Photos by NKL.

Fig. 6.
Fig. 6.

Illustrations of four odontode shape and size types observed across species of Chaetostoma. Illustrations by VAC.

Fig. 7.
Fig. 7.

Chaetostoma bifurcum, new species, from three drainages along the Pacific Coast of Ecuador: (A) Esmeraldas (ROM 93662, 59.7 mm SL), (B, C) Guayas (B: ROM 93721*, 83.7 mm SL; and C: ROM 93729, 91.9 mm SL), and (D) Santa Rosa (ROM 93787*, 96.3 mm SL) river drainages. Scale bars  =  1 cm. Photos by NKL.

Fig. 8.
Fig. 8.

Original illustrations (A, C–G) and photograph (B) of the types of seven species of Chaetostoma from the Pacific Coast of South America. Illustrations (A, G, E) from Regan (1912), (C) from Regan (1904), (D) from Fowler (1944), and (F) from Fowler (1945). Photograph (B; CAS 60167) courtesy of the California Academy of Sciences.

Fig. 9.
Fig. 9.

(A) Map of northwestern South America and southern Central America, and (B, C) enlargements of Ecuador and northern Peru showing the distributions of specimens of (B) Chaetostoma breve and Ch. microps, and (C) Ch. bifurcum, new species, Ch. carrioni, Ch. dermorhynchum, and Ch. trimaculineum, new species, that were examined in this study. Star  =  type locality.

Fig. 10.
Fig. 10.

Topotypes of Chaetostoma carrioni from the Zamora River (Ecuador, Santiago River drainage, Atlantic Slope, ROM 93845*): (A) 60.2 mm and (B) 56.3 mm SL. Scale bars  =  1 cm. Photos by NKL.

Fig. 11.
Fig. 11.

Original illustration (A, from Eigenmann and Allen, 1942) and photos (B, C) of Chaetostoma lineopunctatum. Photographed specimen from the Ucayali River drainage (Rio Coribeni, ANSP 180442, 80.5 mm SL). Photos by M. H. Sabaj Pérez.

Fig. 12.
Fig. 12.

Chaetostoma microps head shape and color variation found in populations from the: Napo (A, D, E, F), and Santiago (B, C; type locality) river drainages of Ecuador (A, F: ROM 93949*; B: ROM 93902, C: ROM 93895*, D: ROM 93948, E: ROM 93948). Photos by NKL.

Fig. 13.
Fig. 13.

Lateral views of Chaetostoma trimaculineum, new species. (A) Holotype from the Santiago River drainage (ROM 93894*, 127.1 mm SL) and (B) paratype from the Marañon River drainage (AUM 45524*, 77.2 mm SL). Scale bar  =  1 cm. Photos by NKL.

Fig. 14.
Fig. 14.

Dorsal views of Chaetostoma trimaculineum, new species. (A) Holotype from the Santiago River drainage (ROM 93894*, 127.1 mm SL) and (B) paratype from the Marañon River drainage (AUM 45524*, 77.2 mm SL). Scale bar  =  1 cm. Photos by NKL.

Received: 14 Nov 2014
Accepted: 07 May 2015
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