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A new large species of Myloplus (Characiformes, Serrasalmidae) from the Rio Madeira basin, Brazil.

Andrade MC, Jégu M, Giarrizzo T - Zookeys (2016)

Bottom Line: Myloplus zorroi sp. n. is described from the Rio Madeira Basin in Amazonia.Like other Myloplus species, Myloplus zorroi sp. n. differs from Utiariticthys by having a deeper body, approximately 60% of standard length (versus usually less than 50% of standard length).Comparisons of the new species with nominal species of Myloplus, representatives of the Myleus clade, and other related taxa are provided.

View Article: PubMed Central - HTML - PubMed

Affiliation: Universidade Federal do Pará, Cidade Universitária Prof. José Silveira Netto. Laboratório de Biologia Pesqueira e Manejo dos Recursos Aquáticos, Grupo de Ecologia Aquática. Avenida Perimetral, 2651, Terra Firme, 66077830. Belém, PA, Brazil; Programa de Pós-Graduação em Ecologia Aquática e Pesca. Universidade Federal do Pará, Instituto de Ciências Biológicas. Cidade Universitária Prof. José Silveira Netto. Avenida Augusto Corrêa, 1, Guamá, 66075110. Belém, PA, Brazil.

ABSTRACT
Myloplus zorroi sp. n. is described from the Rio Madeira Basin in Amazonia. The new species had been treated as an undescribed Tometes species because of the absence of a marked abdominal keel and few small spines forming its prepelvic serrae, features commonly found in the species of the Myleus clade of the Serrasalmidae (species of genera Myleus, Mylesinus, Ossubtus and Tometes) and also in species of Utiaritichthys. Myloplus zorroi sp. n. shares the following characters with its congeners and Utiaritichthys: molariform teeth (versus incisiform teeth in Myleus clade members); a labial row of premaxillary teeth separated from lingual row by an internal gap (versus absence of internal gap between premaxillary teeth rows); and an ascending process of premaxilla wide from its base to the tip (versus ascending process tapering from its base to the tip). Like other Myloplus species, Myloplus zorroi sp. n. differs from Utiariticthys by having a deeper body, approximately 60% of standard length (versus usually less than 50% of standard length). Considering all the morphological evidence, including the presence of 13-19 low spines forming the prepelvic serrae in Myloplus zorroi sp. n. versus more than 20 high spines forming a marked prepelvic keel in other species of Mylopus, the new species is here assigned to Myloplus. Comparisons of the new species with nominal species of Myloplus, representatives of the Myleus clade, and other related taxa are provided.

No MeSH data available.


Related in: MedlinePlus

Ventral view of skeletonized premaxilla. AMyloplusrubripinnis, GEA 1301, 278 mm SLBMyloplusrhomboidalis, GEA 1500, 280 mm SL. Scale bars: 5 mm.
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Figure 3: Ventral view of skeletonized premaxilla. AMyloplusrubripinnis, GEA 1301, 278 mm SLBMyloplusrhomboidalis, GEA 1500, 280 mm SL. Scale bars: 5 mm.

Mentions: Mylopluszorroi sp. n. can be distinguished from its congeners by the absence of abdominal keel and the prepelvic serrae formed by 13–19 low spines (Fig. 2), in contrast to a well-marked abdominal keel and prepelvic serrae of more than 20 high spines. The new species is distinguished from Myloplusasterias, Mylopluslevis, and Myloplustorquatus by the presences of fewer branched dorsal-fin rays (20–22 versus 23 or greater), and from Myloplusarnoldi, Myloplusternetzi, and Myloplustorquatus by having a greater number of branched anal-fin rays (32–34 versus 31 or fewer). Mylopluszorroi differs significantly from Mylopluslobatus, Myloplusschomburgkii, and Myloplusrhomboidalis by having two rows of premaxillary teeth forming a slight arc (e.g., Fig. 3a) versus two rows of premaxillary teeth forming a shape that resembles the uppercase letter “A” (Fig. 3b). The shorter dorsal-fin base (27.6–30.1% of SL versus 31.8% of SL or higher), and the larger interdorsal distance (11.4–12.7% of SL versus 10.8% of SL or lower) are useful to distinguish Mylopluszorroifrom Myloplusasterias, Mylopluslevis, Myloplusternetzi, and Myloplustorquatus. Furthermore, the new species differs from Myloplusternetzi by the presence of a pair of symphyseal teeth versus their absence. The smaller vertical diameter of the eye (27.3–35.4% of HL versus 35.5% of HL or greater) separates Mylopluszorroi from Myloplusarnoldi, Myloplusasterias, Mylopluslevis, Mylopluslobatus, and Myloplusternetzi. Mylopluszorroi is additionally distinguished from Myloplusarnoldi and Myloplustorquatus by having a greater number of total vertebrae (40–41 versus 37 or less), by having anterior dorsal-fin rays lacking pigmentation (versus strongly dark pigmented anterior dorsal-fin rays in Myloplusarnoldi), and the presence of a diffuse dark band at caudal-fin distal border (versus the presence of a well-defined dark band in Myloplusarnoldi). The elongated fontanel with similarly sized anterior and posterior portions (versus very short posterior fontanel and rounded anterior fontanel) further distinguishes Mylopluszorroi from Myloplusasterias.


A new large species of Myloplus (Characiformes, Serrasalmidae) from the Rio Madeira basin, Brazil.

Andrade MC, Jégu M, Giarrizzo T - Zookeys (2016)

Ventral view of skeletonized premaxilla. AMyloplusrubripinnis, GEA 1301, 278 mm SLBMyloplusrhomboidalis, GEA 1500, 280 mm SL. Scale bars: 5 mm.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829807&req=5

Figure 3: Ventral view of skeletonized premaxilla. AMyloplusrubripinnis, GEA 1301, 278 mm SLBMyloplusrhomboidalis, GEA 1500, 280 mm SL. Scale bars: 5 mm.
Mentions: Mylopluszorroi sp. n. can be distinguished from its congeners by the absence of abdominal keel and the prepelvic serrae formed by 13–19 low spines (Fig. 2), in contrast to a well-marked abdominal keel and prepelvic serrae of more than 20 high spines. The new species is distinguished from Myloplusasterias, Mylopluslevis, and Myloplustorquatus by the presences of fewer branched dorsal-fin rays (20–22 versus 23 or greater), and from Myloplusarnoldi, Myloplusternetzi, and Myloplustorquatus by having a greater number of branched anal-fin rays (32–34 versus 31 or fewer). Mylopluszorroi differs significantly from Mylopluslobatus, Myloplusschomburgkii, and Myloplusrhomboidalis by having two rows of premaxillary teeth forming a slight arc (e.g., Fig. 3a) versus two rows of premaxillary teeth forming a shape that resembles the uppercase letter “A” (Fig. 3b). The shorter dorsal-fin base (27.6–30.1% of SL versus 31.8% of SL or higher), and the larger interdorsal distance (11.4–12.7% of SL versus 10.8% of SL or lower) are useful to distinguish Mylopluszorroifrom Myloplusasterias, Mylopluslevis, Myloplusternetzi, and Myloplustorquatus. Furthermore, the new species differs from Myloplusternetzi by the presence of a pair of symphyseal teeth versus their absence. The smaller vertical diameter of the eye (27.3–35.4% of HL versus 35.5% of HL or greater) separates Mylopluszorroi from Myloplusarnoldi, Myloplusasterias, Mylopluslevis, Mylopluslobatus, and Myloplusternetzi. Mylopluszorroi is additionally distinguished from Myloplusarnoldi and Myloplustorquatus by having a greater number of total vertebrae (40–41 versus 37 or less), by having anterior dorsal-fin rays lacking pigmentation (versus strongly dark pigmented anterior dorsal-fin rays in Myloplusarnoldi), and the presence of a diffuse dark band at caudal-fin distal border (versus the presence of a well-defined dark band in Myloplusarnoldi). The elongated fontanel with similarly sized anterior and posterior portions (versus very short posterior fontanel and rounded anterior fontanel) further distinguishes Mylopluszorroi from Myloplusasterias.

Bottom Line: Myloplus zorroi sp. n. is described from the Rio Madeira Basin in Amazonia.Like other Myloplus species, Myloplus zorroi sp. n. differs from Utiariticthys by having a deeper body, approximately 60% of standard length (versus usually less than 50% of standard length).Comparisons of the new species with nominal species of Myloplus, representatives of the Myleus clade, and other related taxa are provided.

View Article: PubMed Central - HTML - PubMed

Affiliation: Universidade Federal do Pará, Cidade Universitária Prof. José Silveira Netto. Laboratório de Biologia Pesqueira e Manejo dos Recursos Aquáticos, Grupo de Ecologia Aquática. Avenida Perimetral, 2651, Terra Firme, 66077830. Belém, PA, Brazil; Programa de Pós-Graduação em Ecologia Aquática e Pesca. Universidade Federal do Pará, Instituto de Ciências Biológicas. Cidade Universitária Prof. José Silveira Netto. Avenida Augusto Corrêa, 1, Guamá, 66075110. Belém, PA, Brazil.

ABSTRACT
Myloplus zorroi sp. n. is described from the Rio Madeira Basin in Amazonia. The new species had been treated as an undescribed Tometes species because of the absence of a marked abdominal keel and few small spines forming its prepelvic serrae, features commonly found in the species of the Myleus clade of the Serrasalmidae (species of genera Myleus, Mylesinus, Ossubtus and Tometes) and also in species of Utiaritichthys. Myloplus zorroi sp. n. shares the following characters with its congeners and Utiaritichthys: molariform teeth (versus incisiform teeth in Myleus clade members); a labial row of premaxillary teeth separated from lingual row by an internal gap (versus absence of internal gap between premaxillary teeth rows); and an ascending process of premaxilla wide from its base to the tip (versus ascending process tapering from its base to the tip). Like other Myloplus species, Myloplus zorroi sp. n. differs from Utiariticthys by having a deeper body, approximately 60% of standard length (versus usually less than 50% of standard length). Considering all the morphological evidence, including the presence of 13-19 low spines forming the prepelvic serrae in Myloplus zorroi sp. n. versus more than 20 high spines forming a marked prepelvic keel in other species of Mylopus, the new species is here assigned to Myloplus. Comparisons of the new species with nominal species of Myloplus, representatives of the Myleus clade, and other related taxa are provided.

No MeSH data available.


Related in: MedlinePlus