Lophiosilurus alexandri: MZUEL , 3, to mm SL, Estação de Piscicultura de Três Marias, CODEVASF, on the upper São Francisco. The “pacamã”, Lophiosilurus alexandri, is a particularly interesting case for addressing this problem. Lophiosilurus alexandri is the largest.

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Eyes placed laterally on the head are a condition shared by all Pseudopimelodidae except for juvenile and adult Lophiosilurus. Lophioxilurus Examined Lophiosilurus alexandri: Previous studies regarding the anatomy of Lophiosilurus alexandri included Nakatani et al.

Origin of pelvic fin at vertical through end of dorsal-fin base; pelvic fin reaching anal fin when adpressed.

Lophiosilurus alexandri

Species of most genera of Pseudopimelodidae also present a well-developed lateral line that extends on the body from head to caudal-fin base. On the other hand, the condition of elongate middle rays of the upper caudal-fin lobe is only present in Lophiosilurusand therefore, another autapomorphy of the species. Even though fully developed specimens of the latter have the coloration of Lophiosilurusjuveniles of C.

Anal fin well developed on day 8, but still associated with primordial fin; final development of anal fin on day Yolk sac very large immediately after hatching Fig 1adecreasing in volume in specimens one or two days post-hatching Fig 1b. Anal-fin base shorter than adipose-fin base.

Box plot of standard length by age in days x-axis of Lophiosilurus alexandri.

Juvenile period Stage observed from 49 to 60 days after hatching. Twenty-three measurements were obtained on juveniles using a digital caliper accurate to 0.

Dorsal fin well developed with short, thick, strong anterior spine and six soft rays. Accordingly, Lophiosilurus alexandri is an ideal species to observe the morphological changes during ontogeny, and to seek solid interpretations on the polarity of characters.

The Biogenetic law, proposed by Haeckel [ 2 ] and reformulated by Nelson [ 1 ], says that the steps of an ontogenetic series can be directly translated into an ordered series of character states. alexaneri

This is an open access article distributed under the terms of the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Species of most genera of Pseudopimelodidae, including Lophiosilurushave an axillary gland that produces mucus and is located immediately beneath the anterior portion of the posterior cleithral process.


At 42 days, hooks on anterior and posterior margins of pectoral-fin spine similar in size Fig 5c. Dorsal lobe of caudal fin long, almost twice as long as ventral lobe. In Lophiosilurusthis gland starts to develop in flexion stage larvae as a white tissue cluster immediately above the primary pectoral fin.

Primordial adipose fin persistent as part of dorsal portion of finfold, confluent with caudal fin; terminus of adipose lophhiosilurus evident as small notch, otherwise confluent with caudal fin. The position of the mouth has also undergone major changes during the development of Lophiosilurus. Roberts TR Unculi Horny projections arising from single cellsan adaptive feature of the epidermis of ostariophysan fishes.

Pseudopimelodidae are Neotropical catfishes characterized by having slightly to strongly depressed body in fully developed lophlosilurus. The caudal fin is responsible for swimming in most fishes [ 29 ], and the upper lobe is distinctly wider than the lower lobe in species that are typically benthic and need fast bottom-up movements [ 303132 ]. Therefore, the relative depth of the body is a phylogenetic character with at least two states perhaps more, if a more accurate morphometric analysis is performeda relatively deep body being plesiomorphic and a relatively depressed body being apomorphic.

Accessed Dez Pelvic fin, when adpressed, reaching origin of anal-fin base.

Comparative material Batrochoglanis acanthochiroides: The search for the morphological changes that gave rise to the present diversity of forms and taxa continues to be one of the main goals of Evolutionary Biology. Published online Apr This interpretation favors the hypothesis that Cruciglanis and Pseudopimelodus are sister to all other Pseudopimelodidae, both taxa having a relatively deep body compared to other species of the family.

Mouth not formed soon after hatching; visible in subterminal position after the first day of development. Placement of the eyes on the dorsal surface of the head is a condition unique to juvenile and adult Lophiosilurusand therefore an autapomorphy of the species.


Noteworthy to say that some of the features thought to be completely modified in adults of Lophiosilurus alexandri autapomorphicand therefore uninformative for the evolution of other species of Pseudopimelodidae, were in fact part of a complex character-state series that is traceable through ontogeny.

Cruciglanisa new genus of Pseudopimelodid catfish Ostariophysi: However, the condition in larvae and juveniles of Lophiosilurus is similar to the one present in the other species of pseudopimelodids. Pseudopimelodidae from the Sao Francisco River basin, Brazil.

Schultze HP, Arratia G. Relative to standard length, measurements of snout length, head depth and body depth are smaller in juveniles than in larvae, but body width is larger.

Conceived and designed the experiments: New interpretations on the phylogenetic characters related to these changes are provided in view of the two alternative hypotheses of the evolution of Pseudopimelodidae.

Lophiosilurus alexandri – Wikiwand

Caudal fin with seven dorsal procurrent rays, 13 principal rays and seven ventral procurrent rays Fig 3a. Homologization of caudal skeletal structures. Skin of head with small wart-like appendages mainly on supraorbital and ventral regions. Siluriformes with description of a new species from the Colombian Pacific coast. Pectoral fin formation starting on day 7 with emergence of rays; completely developed after day These papillae are formed by an accumulation of keratin, and are distinct from the tubercles present in other catfishes [ 34353637 ] by lacking unculiferous cells [ 38 ].

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Maxillary barbel not reaching gill opening. Esqueleto caudal de peces Siluriformes y sus tendencias evolutivas.

Generelle Morphologie der Organismen: ANSP1, The cephalic portion of the system is formed in the postflexion larvae. In 60 day old specimens, head wider than long. Spawning is parceled and the female lays large adhesive eggs 3.