Research Article |
Corresponding author: Fábio F. Roxo ( roxoff@hotmail.com.br ) Academic editor: Nina Bogutskaya
© 2015 Fábio F. Roxo, Luz E. Ochoa, Gabriel S. C. Silva, Claudio Oliveira.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Roxo FF, Ochoa LE, Silva GSC, Oliveira C (2015) Rhinolekos capetinga: a new cascudinho species (Loricariidae, Otothyrinae) from the rio Tocantins basin and comments on its ancestral dispersal route. ZooKeys 481: 109-130. https://doi.org/10.3897/zookeys.481.8755
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The present study deals with the description of a new species of Rhinolekos. It can be distinguished from its congeners by having 31 vertebrae, the anterior portion of the compound supraneural-first dorsal-fin proximal radial contacting the neural spine of the 9th vertebra, the absence of transverse dark bands in the pectoral, pelvic and anal-fin rays, 24–28 plates in the dorsal series, the lack of odontodes on the ventral tip of the snout, the absence of accessory teeth, a greater prenasal length, a smaller head length, and by a greater snout length. Rhinolekos capetinga is restricted to the headwaters of the rio Tocantins and it is the first species of this genus in the Amazon basin. Additionally, we present a brief discussion of a biogeographic scenario that may explain the dispersal of the new species from the rio Paranaíba to the rio Tocantins basin. We suggest that the ancestral lineage of R. capetinga reached the rio Tocantins from portions of the rio Paranaíba at the end of the Miocene, about 6.3 Mya (4.1–13.9 Mya 95% HPD), probably as a result of headwater capture processes among adjacent drainages.
Biodiversity, Freshwater, Neotropical fish, South America, Taxonomy
Otothyrinae sensu
Rhinolekos is the most recently described genus of Otothyrinae and differs from its members, mainly by having the anterior portion of the compound supraneural-first dorsal-fin proximal radial contacting the neural spine of the 9th or 10th vertebrae and by the presence of the lateronasal plate. Currently, Rhinolekos includes three valid species: R. britskii Martins & Langeani, 2011a, R. schaeferi Martins & Langeani, 2011a and R. garavelloi Martins & Langeani, 2011a, all of which were described from drainages of the rio Paranaíba (upper rio Paraná basin).
Furthermore, several authors discussed the historical dispersal of the ancient fauna among adjacent drainages of South America Platform (e.g.
Recently, during collecting expeditions in small tributaries of the rio Tocantins, the major drainage of the Brazilian Shield (
After collection, fish were anesthetized using 1% benzocaine in water, fixed in 10% formaldehyde, and preserved in 70% ethanol for morphological study. Institutional acronyms follow
We used Diplomystes mesembrinus to root our phylogeny. Additionally, samples of Corydoras imitator, Corydoras oiapoquensis, Hoplosternum littorale, Callichthys callichthys, Astroblepus sp. 1 and Astroblepus sp. 2, Hemipsilichthys gobio, H. papillatus, Delturus parahybae, Rineloricaria lanceolata, Spatuloricaria sp. 1, Hypostomus ancistroides, H. nigromaculatus and H. microstomus were used as additional outgroups. We included in the analysis 155 specimens representing 115 loricariid species (see Suppl. material
Vouchers of the molecular study were deposited at the collection of the Laboratório de Biologia e Genética de Peixes (LBP); the Museu de Ciências e Tecnologia, Pontifícia Universidade Católica do Rio Grande do Sul (MCP); the Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (NUP); and the Museum of Natural History of the City of Geneva (MHNG).
Total DNA was extracted from ethanol preserved muscle samples with the DNeasy Tissue Kit (Qiagen), following manufacturer’s instructions. Partial sequences of the genes 16S rRNA (Kocher et al. 1989), cytochrome b (Cytb) (
The phylogenetic analysis was performed according to
Maximum likelihood analyses were performed using RAxML Web-Servers (
Bayesian inference (BI) (
The time calibrated phylogeny was performed according to
Data on the geographic distributions of species were taken from the original species descriptions and information available at the Catalog of
The maximum-likelihood analysis of biogeographic history was performed in Lagrange v2.0 (
Rhinolekos sp. 1 –
MZUSP 116102, (male, 37.5 mm SL), Brazil, Goiás State, municipality of Água Fria de Goiás, córrego da Branca, drainage of the rio Tocantizinho, rio Tocantins basin, 14°53'47.2"S, 47°34'58.4"W, 30 June 2014, FF Roxo, GSC Silva, LE Ochoa.
Brazil, Goiás State, rio Tocantins basin (56 specimens). LBP 17089 (1 male, 39.1 mm SL), municipality of Agua Fria de Goiás, córrego da Branca, drainage of the rio Tocantizinho, 14°57'01.6"S, 47°35'57.0"W, 21 November 2012, R Devidé, BF Melo, JMH Martinez, GSC Silva; LBP 18996, (1 female, 24.1 mm SL), municipality of São João D’Aliança, córrego Roncador, drainage of the rio Tocantizinho, 14°43'51.3"S, 47°32'34.0"W, 30 June 2014, FF Roxo, GSC Silva, LE Ochoa; LBP 19001 (15 females, 26.8–36.2 mm SL, 20 males, 39.5–30.2 mm SL, 3 c&s, 37.2–32.6 mm SL, 9 unsexed juveniles not measured), collected with holotype. LBP 19466 (2 females, 36.5–37.1 mm SL) municipality of Água Fria de Goiás, córrego da Branca, drainage of the rio Tocantizinho, 14°53'47.2"S, 47°34'58.4"W, 09 November 2014, FF Roxo, LH Roxo, GSC Silva, LE Ochoa; MZUSP 113920 (2 females, 29.3–37.3 mm SL, 3 males, 30.4–39.0 mm SL), municipality of Água Fria de Goiás, córrego da Branca, drainage of the rio Tocantizinho, 14°53'47.2"S, 47°34'58.4"W, 27 November 2012, OT Oyakawa, AM Zanata, P Camelier, M Melo.
Rhinolekos capetinga differs from R. garavelloi and R. schaeferi in that it has a lower number of vertebrae, 31 (vs. 32) and the anterior portion of the compound supraneural-first dorsal-fin proximal radial contacts the neural spine at the 9th vertebra (vs. 10th, Fig.
Rhinolekos capetinga, LBP 19001, paratype, 34.5 mm SL. a Anterior portion of axial skeleton and dorsal-fin supports (left side, lateral view). Vertebrae counts included five vertebrae of the Weberian apparatus. np nucal plate; rv6 rib of sixth vertebrae; px2 compound proximal and medial radial 2; sn+px1 compound supraneural first dorsal-fin proximal radial; sp1 first dorsal-fin spinelet; sp2 second dorsal-fin spine; v6−12 vertebrae 6−12 b Skull of R. capetinga; f frontal; soc supraoccipital; cpt parieto-supraoccipital; op opercle; io1−5 infraorbitals; pop preopercle; cp 1−2 cheek plates; pr 1−3 postrostral plates; pf prefrontal plates; le lateral ethmoid; n nasal; lpn lateronasal plate; r rostral plate; pn prenasal; sp sphenotic.
Morphometric and meristic data presented in Table
Morphometrics and meristic data for R. capetinga. SD, standard deviation.
Rhinolekos capetinga, holotype and paratypes (n=30) | ||||
---|---|---|---|---|
Holotype | Range | Mean | SD | |
SL | 37.5 | 22.9–39.1 | 34.3 | 3.6 |
Percents of SL | ||||
Predorsal length | 42.2 | 38.9−49.9 | 44.7 | 2.0 |
Preanal length | 53.4 | 48.2−60.3 | 54.0 | 2.7 |
Prepectoral length | 26.2 | 19.1−26.2 | 23.2 | 1.4 |
Prepelvic length | 33.3 | 31.5−39.5 | 35.2 | 2.0 |
Postanal length | 34.4 | 28.0−38.7 | 34.8 | 2.5 |
Thoracic length | 13.1 | 9.6−15.2 | 12.9 | 1.5 |
Abdominal Length | 19.7 | 11.8−23.5 | 19.2 | 2.2 |
Caudal peduncle depth | 6.6 | 5.8−8.6 | 6.9 | 0.6 |
Head length | 21.6 | 19.6−26.6 | 22.4 | 1.5 |
Head width | 22.1 | 17.6−26.6 | 21.8 | 1.8 |
Head depth | 11.9 | 10.8−15.7 | 12.8 | 1.0 |
Base of dorsal-fin length | 10.9 | 9.3−13.0 | 10.5 | 1.0 |
Folded dorsal-fin length | 20.7 | 13.9−21.3 | 19.1 | 1.4 |
Pectoral-fin unbranched ray length | 20.1 | 13.6−22.9 | 19.9 | 1.9 |
Pelvic-fin unbranched ray length | 15.3 | 13.3−17.5 | 15.6 | 1.2 |
Snout-opercle length | 21.8 | 18.8−26.3 | 21.9 | 1.5 |
Percents of HL | ||||
Snout length | 60.9 | 60.7−85.2 | 72.4 | 5.8 |
Orbital diameter | 19.6 | 12.2−23.2 | 17.1 | 2.3 |
Interorbital length | 45.4 | 40.4−55.8 | 46.6 | 3.8 |
Prenasal length | 48.8 | 41.3−60.2 | 51.4 | 4.4 |
Suborbital depth | 26.3 | 19.0−39.7 | 25.6 | 4.5 |
Meristics | Holotype | Range | Mode | SD |
Left premaxillary teeth | 26 | 15−34 | 22 | – |
Left dentary teeth | 24 | 14−31 | 26 | – |
Dorsal plates | 27 | 24−28 | 27 | – |
Mid-dorsal plates | 17 | 16−20 | 18 | – |
Median plates | 25 | 23−27 | 25 | – |
Mid-ventral plates | 25 | 20−24 | 22 | – |
Ventral plates | 18 | 15−18 | 17 | – |
Head rounded in dorsal view. Snout slightly pointed, its tip rounded, elongated (61–85% of HL) and depressed in front of each nostril on dorsal surface. Anterior margin of snout covered with odontodes, except ventral tip of snout; odontodes of margin of snout similar in size to remaining ones found on head. Odontodes on head and trunk well defined and not forming longitudinal rows; eye small (12–23% of HL), dorsolaterally positioned; iris operculum not present; lips roundish and papillose; papillae uniformly distributed on base of dentary and premaxillary and slightly decreasing distally. Lower lip larger than upper lip; its border fringed; maxillary barbel present; Teeth slender and bicuspid; mesial cusp larger than lateral cusp; premaxillary teeth 15–34. Dentary teeth 14–30.
Dorsal fin ii,6-7; dorsal-fin spinelet short, roughly triangular shaped, locking mechanism non-functional; dorsal-fin origin slightly posterior of vertical through pelvic-fin origin. Anterior portion of compound supraneural-first dorsal-fin proximal radial contacting neural spine of 9th vertebrae (Fig.
Body covered with bony plates except on ventral part of head, around pectoral and pelvic-fin origin and on dorsal-fin base. Cleithrum and coracoid totally exposed; Arrector fossae partially enclosed by ventral lamina of coracoids. Abdomen entirely covered by plates in adults (about 25.0 mm SL); lateral plate series with elongate and large plates, formed by two lateral plate series, similar in size; median plates formed by four to five irregular plate series reaching anal shield. Lateral side of body entirely covered by plates; mid-dorsal and mid-ventral plates well developed, reaching typical adipose-fin region.
Parts of head osteology presented in Fig.
Pale yellowish ground color. Dorsal surface of head dark brown, except for pale yellowish areas on snout tip. Four dark-brown saddles crossing dorsum, reaching longitudinal dark strip on side of trunk: first at dorsal-fin origin, second below dorsal-fin base, third typically at adipose-fin region, and fourth at end of caudal peduncle. Caudal-fin black, with small hyaline circular area on each lobe, tip of lobes hyaline; some specimens with caudal-fin lobe entirely dark (Fig.
Similar pattern described for living specimens, but with ground color dark brown (Fig.
Adult males are distinguished by having a papilla at the urogenital opening (vs. papilla absent in females), and by an unbranched pectoral- and pelvic-fin ray supporting a dermal flap on their proximal dorsal surface in males.
The specific name capetinga from the Tupi-guarani dialect is in reference to the old and unused name of São João D´Aliança municipality. The name «capetinga» means white, or clear water. A noun in apposition.
Rhinolekos capetinga is known from two localities at the córrego da Branca and one locality at the córrego Roncador, all drainages of the rio Tocantizinho, rio Tocantins basin (Fig.
a Map showing the distribution of R. capetinga. Type locality at córrego da Branca, green star – 14°53'47.2"S, 47°34'58.4"W. Paratype localities at córrego da Branca, red star – 14°57'01.6"S, 47°35'57.0"W, and at córrego Roncador, pink star – 14°43'51.3"S, 47°32'34.0"Wb Habitat and submerged vegetation where the specimens were found in type locality of córrego da Branca, 14°53'47.2"S, 47°34'58.4"W. Photo: LH Roxo.
Rhinolekos capetinga was collected on flat areas of the córrego da Branca and córrego Roncador, rio Tocantins basin, in places of shallow clear waters, about 1 m depth and median to fast current flow. The fishes captured were associated with the vegetation that covers the bottom and the border of the headwaters (Fig.
Partial sequences of the three mitochondrial genes (16S rRNA, COI, Cytb) and one nuclear gene (F-reticulon 4) were obtained from GenBank (Suppl. material
Our time calibrated phylogeny and the ancestral area reconstruction (Suppl. material
Biogeographic distribution and time-calibrated phylogenetic tree of Microlepidogaster and Rhinolekos species, based on three mitochondrial (16SrRNA, COI, Cytb) and one nuclear marker (F-reticulon 4), modified from figure 7 of
The new species Rhinolekos capetinga is a typical species of the genus, given that it presents the main characters used by
The anterior portion of the compound supraneural-first dorsal fin proximal radial contacting the neural spine of the 9th vertebrae (Fig.
Rhinolekos capetinga is the first species of Rhinolekos described in the rio Tocantins basin. Results of
Several authors (e.g.
Microlepidogaster arachas Martins, Calegari & Langeani, 2013: LBP 10882, 3, 22.3−36.3 mm SL, rio Araguari, rio Paranaíba basin; LBP 11724, 9, 38.0−41.2 mm SL, 1 c&s, 39.1 mm SL, córrego sem nome, rio Paranaíba basin; Microlepidogaster discus Martins, Rosa & Langeani, 2014b: MZUSP 115384, 2, 38.8−40.4 mm SL, rio Itacambiruçu, rio Jequitinhonha basin; Microlepidogaster dimorpha Martins & Langeani, 2011b: LBP 10683, 2, 28.8−35.6 mm SL, rio Uberaba, upper rio Paraná basin; Microlepidogaster longicolla Calegari & Reis, 2010: LBP 17077, 4, 39.7−46.4 mm SL, rio Pipiripari, upper rio Paranaíba basin; LBP 17060, 39.1−40.2 mm SL, córrego Maria Velha, upper rio Paranaíba basin; Microlepidogaster perforatus Eigenmann & Eigenmann, 1889: LBP 19498, 1, 28.9 mm SL, rio Carandaí, rio São Francisco basin; Rhinolekos britskii Martins & Langeani, 2011a: LBP 7245, 3, 28.9−30.5 mm SL, rio Arapuca, rio Paranaíba basin; LBP 7253, 15, 21.7−35.2 mm SL, córrego sem nome, rio Paranaíba basin; MZUSP 103698, 6 paratypes, 27.1−36.1 mm SL, córrego sem nome, rio Paranaíba basin; Rhinolekos garavelloi Martins & Langeani, 2011a: LBP 7246, 24, 24.1−34.8 mm SL, córrego Fazenda Lageado, rio Paranaíba basin; MZUSP 103697, 5 paratypes, 21.4−31.9 mm SL, córrego da Fazenda Lageado, rio Paranaíba basin; Rhinolekos schaeferi Martins & Langeani, 2011a: LBP 19460, 1, 28.5 mm SL, córrego Fazenda Garaíbas, rio Paranaíba basin; LBP 19461, 1, 36.6 mm SL, córrego Fazenda Garaíbas, rio Paranaíba basin; Rhinolekos sp.: LBP 7247, 26, 24.1−33.1 mm SL, córrego Fazenda Balsamo, rio Paranaíba basin.
The authors wish to thank Angela M. Zanata, Bruno F. Melo, Jefferson M. Henriques, Luiz H. Roxo, Marcelo Melo, Oswaldo T. Oyakawa, Priscila Camelier, and Renato Devidé for their help during the collection expeditions, Ricardo Britzke for reading the manuscript and giving valuable suggestions and Maria Thereza P. Jorge for the English revision. This research was supported by the Brazilian agencies FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo, proc. 2014/05051-5 to FFR, 2014/06853-8 to LEO and 2012/01622-2 to GSCS) and MCT/CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) (Edital Universal, proc. N. 441347/2014–2 coord. FFR).
Fig. S1
Data type: Adobe PDF file
Fig. S2
Data type: Adobe PDF file
Table S1
Data type: Microsoft Word document
Explanation note: Species included in the present study.
Table S2
Data type: Microsoft Word document
Explanation note: Primers used in the present study to amplify partial sequences of F-reticulon 4, 16S rRNA, cytochrome oxidase subunit I (COI) and cytochrome B (CytB).
Table S3
Data type: Microsoft Word document
Explanation note: DEC models tested to estimate distribution ranges inherited by the descending lineages at each node of the tree. The differences between the models are in the rate of dispersal among adjacent and no adjacent areas. * Represent the model used in the analysis.