Saturday, May 19, 2018

[Ichthyology • 2018] Hypostomus renestoi • Redescription of Hypostomus latirostris (Regan, 1904) with the Recognition of A New Species of Hypostomus (Siluriformes: Loricariidae) from the upper rio Paraguay Basin, Brazil



Hypostomus renestoi Zawadzki, da Silva & Troy, 2018

Hypostomus latirostris  (Regan, 1904)

 DOI:  10.23788/IEF-1079 

Hypostomus latirostris was originally described by Regan (1904) from “River Jungada [= rio Jangada], Matto Grosso and Goyaz”; however, the species is rarely mentioned in taxonomic works on Hypostomus from Paraguay. Herein, the two syntypes of Plecostomus latirostris were examined showing critical differences between them. After the analysis of a large sample of recently collected specimens from the upper rio Paraguay basin we concluded that the two syntypes from the rio Jangada indeed belong to different species. Hypostomus latirostris is redescribed and a lectotype is designated herein. The other syntype (now a paralectotype of H. latirostris) is designated as paratype of Hypostomus renestoi, new speciesHypostomus renestoi can be differentiated from H. latirostris by having robust teeth (vs. slender); by having 28-77 teeth on the premaxilla (vs. 79-111) and 25-64 on the dentary (vs. 79-109); by having small and more conspicuous dark spots (vs. larger and less conspicuous dark spots); by having dorsal and mid-dorsal series of plates with moderate hypertrophied odontodes (vs. lacking hypertrophied odontodes on lateral series of plates); and usually by attaining a smaller size. 


Fig. 7. Hypostomus renestoi, MCP 49767, holotype, 121.8 mm SL; Brazil: Mato Grosso State: rio Diamantino, upper rio Paraguay basin. Photographed alive.
Fig. 2. Hypostomus latirostris, NUP 3975, 127.0 mm SL; Brazil: Mato Grosso State: rio Jangada, upper rio Paraguay basin. Photographed alive. 

Hypostomus latirostris (Regan, 1904)

Plecostomus pantherinus (not Kner, 1854): Boulenger, 1892: 9. 
Plecostomus latirostris Regan, 1904: 213, Pl. 11, Fig. 1. Type locality: Rio Jungada [= Jangada], Matto Grosso and Goyaz [Brazil]. Syntypes: BMNH 1892.4.20.26-27 (2); Gosline, 1947: 115 (brief comments). 
Hypostomus latirostris – Burgess, 1989: 431 (checklist); Isbrücker, 1980: 25 (checklist); Montoya-Burgos et al., 2002: 374 (Fig. 2; molecular phylogeny); Montoya-Burgos, 2003: 1859, Fig. 2; molecular phylogeny); Weber, 2003: 359 (checklist); Ferraris, 2007: 255 (checklist); Cardoso et al., 2012: 74 (Fig. 2; molecular phylogeny). 
Hypostomus sp. – Werner et al., 2005: 197 (L224, photo 3; neighborhood rio Cuiabá) and 302 (L388, photo 1; waters flowing to rio Cuiabá near Cuiabá). 
Hypostomus sp. 2 – Veríssimo et al., 2007: 6 (checklist, Manso Reservoir, upper rio Paraguay basin, Brazil). 
Hypostomus cf. latirostris - Renesto et al., 2007: 870 (allozymes).

Distribution and habitat. Hypostomus latirostris is known from several localities along the rio Cuiabá basin (Fig. 4). Regan (1904) pointed out the rio Jangada as the type locality. Records of H. latirostris were made in all the extension of the rio Manso and also in the rio Cuiabá basin. The rio Manso and the rio Cuiabazinho are the formers to rio Cuiabá. The rio Cuiabá basin is mainly located upstream the Brazilian Pantanal. Most specimens were collected before and after the construction of the Manso Reservoir. The rio Cuiabá basin has clear water, with rocky and sandy substrate, and variable remnant riparian vegetation. The individuals were collected whether in rapids or in lentic environments. Juveniles were usually collected in oxbow lakes in the rio Cuiabá basin and streams. Specimens of H. latirostris were collected co-occurring with H. boulengeri, H. cochliodon, H. khimaera, H. latifrons, H. piratatu, H. regani, H. ternetzi, H. peckoltoides, and H. mutucae.


Hypostomus renestoi, new species 

Plecostomus latirostris Regan, 1904: 213 (partim). Type locality: Rio Jungada, Matto Grosso [Brazil]. Syntypes: BMNH 1892.4.20.26-27 (2). 
Hypostomus sp.: Werner et al., 2005: 302 (L389, photo 2; waters flowing to rio Cuiabá near Cuiabá). 
Hypostomus sp. 3 – Renesto et al., 2007: 870 [allozymes]. 
Hypostomus sp. 4 – Veríssimo et al., 2007: 6 (checklist, Manso Reservoir, upper rio Paraguay basin, Brazil).

Diagnosis. Hypostomus renestoi is distinguished from the species of the H. cochliodon group (sensu Zawadzki & Hollanda Carvalho, 2015) by having viliform teeth and angle between dentaries usually larger than 80° (vs. spoon- or shovel-shaped teeth and angle between dentaries about 80°); from H. affinis, H. ancistroides, H. arecuta, H. argus, H. aspilogaster, H. borellii, H. boulengeri, H. carinatus, H. careopinnatus, H. carvalhoi, H. commersoni, H. crassicauda, H. delimai, H. derbyi, H. dlouhyi, H. faveolus, H. formosae, H. hemiurus, H. interruptus, H. itacua, H. laplatae, H. niceforoi, H. nigrolineatus, H. nigropunctatus, H. paucimaculatus, H. piratatu, H. plecostomus, H. pantherinus, H. punctatus, H. pusarum, H. scabryceps, H. seminudus, H. subcarinatus, H. tapijara, H. variostictus, H. velhochico, and H. watwata by lacking keels on median lateral series of plates (vs. having moderate or strong keels along lateral series of plates); from H. alatus, H. albopunctatus, H. chrysostiktos, H. fluviatilis, H. francisci, H. margaritifer, H. luteomaculatus, H. lexi, H. luteus, H. margaritifer, H. meleagris, H. microstomus, H. multidens, H. myersi, H. niger, H. regani, H. roseopunctatus, H. scaphyceps, H. sertanejo, H. strigaticeps, H. tietensis, and H. variipictus by having dark spots on a clearer background (vs. pale spots or vermiculations on a darker background); from H. asperatus, H. brevicauda, H. goyazensis, H. heraldoi, H. hermanni, H. iheringii, H. kuarup, H. lima, H. luetkeni, H. macrops, H. mutucae, H. nigromaculatus, H. paulinus, H. topavae, H. unae, and H. wuchereri by having dorsal and mid-dorsal series of plates with moderate hypertrophied odontodes (vs. lacking conspicuous odontodes on lateral series of plates); from H. angipinnatus, H. agna, H. isbrueckeri, H. laplatae, H. latifrons, H. nigropunctatus, H. uruguayensis, and H. vaillanti by having one plate bordering supraoccipital (vs. three to seven); from H. bolivianus, H. fonchii, and H. perdido by having bicuspid teeth (vs. unicuspid teeth); from H. peckoltoides by having dark large spots on body and fins (vs. wide dark transverse bars on body and bands on fins); from H. ternetzi by having ventral unbranched caudal-fin ray length smaller to equal to predorsal length (vs. unbranched caudal-fin ray length clearly larger than predorsal length); from H. latirostris by having: robust teeth (vs. slender); by having 28-77 teeth on premaxilla (vs. 79-111) and 25-64 on dentary (vs. 79-109); small and more conspicuous dark spots (vs. larger and less conspicuous dark spots); dorsal and mid-dorsal series of plates with moderate hypertrophied odontodes (vs. lacking conspicuous odontodes on lateral series of plates); and usually by attaining a smaller size. 

Ecological notes. Sometimes very small black dots due to encysted metacercariae on trunk, belly and fins (Figs. 5, 7). 

Distribution and habitat. Hypostomus renestoi was mainly collected in the rio Cuiabá and its tributaries (Fig. 8). As a small- to medium-sized species, the specimens were collected in small- and medium-sized streams, with ranges from 1.5 to 6 m wide, as well as records were also from the margins or shallow stretches of the larger Cuiabá and Manso rivers. The area sampled presented varied vegetation of degraded areas by mining practices, recreation, pasture, agriculture, and often a small riparian vegetation. The streams usually had as substrate sand, clay, gravel and rocks. Several specimens were collected in rapids on mouth of the tributaries to the rio Manso. With the construction of Manso Reservoir the lower stretches of some tributaries of the rio Manso are nowadays flooded by the lake reservoir. 

Etymology. The specific epithet renestoi is in honor of the professor Erasmo Renesto, Brazilian ichthyologist, due to his contributions to the genetic field of the Neotropical fishes.


 Cláudio Henrique Zawadzki, Hugmar Pains da Silva and Waldo Pinheiro Troy. 2018. Redescription of Hypostomus latirostris (Regan, 1904) with the Recognition of A New Species of Hypostomus (Siluriformes: Loricariidae) from the upper rio Paraguay Basin, Brazil. Ichthyological Exploration of Freshwaters.  DOI:  10.23788/IEF-1079

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