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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Phylogeny and jaw ontogeny of beloniform fishes. Introduction 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.

Placement of the eyes on the dorsal surface of the head is a condition unique to juvenile and adult Lophiosliurusand therefore an autapomorphy allexandri the species. Outer mentonian barbels and maxillary barbels do not exceed the gill opening. The present study contributes with details on the early development of the external morphology in L. Adipose fin completely separate from dorsal fin, but with small tissue connection to caudal fin.

Lophiosilurus alexandri – Wikipedia

Pseudopimelodidae from the Sao Francisco River basin, Brazil. Multiple illustrations were made for stages that exhibited sudden changes in morphology. Caudal, pectoral and pelvic fins largely hyaline, with sparse dark chromatophores Fig 5a.

Base of dorsal fin with chromatophores concentrated in patches. Maxillary barbel not reaching gill opening. Author information Article notes Copyright and License information Disclaimer.

Pelvic fin, when adpressed, lophiosiluruz longer reaching anal fin. In the late stage of postflexion, chromatophores appear more widespread on body, and more concentrated on head, caudal peduncle, and dorsal-fin base Fig 4a and 4b. Schultze HP, Arratia G.

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Axillary gland visible above base of pectoral fin. The dorsalmost rays of the upper oophiosilurus lobe are also longest in slexandri of Batrochoglanis raninus [ 28 ], indicating that this condition may be also present in the remaining Pseudopimelodidae. Anal-fin base becoming longer than adipose-fin base. Morphometric variables were expressed as percentages of standard length, except for subunits of the head, expressed as percentages of head length.

Allgemeine Grundzuge der organischen Formen-Wissenschaft, mechanisch begrundet durch die von Charles Lophiosilurks reformite Descendz-Theoria, 2 vols. However, as specimens grow, the dorsalmost rays of the upper lobe become relatively shorter, and the middle rays of the upper lobe are relatively longer, including the adults.

In fully developed specimens of Lophiosilurusthe body is extremely wide and depressed [ 26 ], a condition that is unique among pseudopimelodids and therefore autapomorphic.

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On the other hand, the relative depths of head and body decrease from post-larval to juvenile stages, the same happens to snout length, anal-fin base length, caudal-peduncle length, interorbital width, inner mentonian barbel length, outer mentonian barbel length, and maxillary barbel length Table 1.

All fin rays segmented.

The regression curve corresponds only to larvae and juveniles loohiosilurus L. Anal fin fully formed, last ray separated from ventral finfold. Mentonian and maxillary barbels larger than in flexion-stage specimens.

Anal fin well developed on day 8, but still associated with primordial fin; final development of anal fin on day The inclusion of the width and depth mean proportions obtained from juveniles and adults of other species of the family, shows a wide distribution of these species along the X alexanfri body depthbut with a tendency to a narrower distribution on the Y axis body width.

At 42 days, hooks on anterior and posterior margins of pectoral-fin spine similar in size Fig 5c. Primordial fin finfold well developed, hyaline, alexandro the body from the post-cephalic region to the post yolk sac region.

Stage absent in L. Species of most genera of Pseudopimelodidae, including Lophiosilurushave an axillary gland that produces mucus and is located alrxandri beneath the anterior portion of the posterior cleithral process. Cruciglanisa new genus of Pseudopimelodid catfish Ostariophysi: Axillary pore very difficult to visualize in larval specimens; associated gland visible by transparency of skin.

USNMholotype, Lateral-line canal well developed to vertical through terminus of dorsal-fin base; lateral line pores evident to vertical through middle of adipose-fin base. Data Availability All relevant data are within the paper. Skin of head with small wart-like appendages mainly on supraorbital and ventral regions.

First ray of pectoral fin begins to differentiate on day 6, lophiosiurus small hooks evident along posterior margin; after day 9, hooks visible on both sides with posterior hooks larger than anterior ones Fig 4c. This monotypic genus also exhibits the most highly modified morphology for the family.

Mouth opened but incompletely developed. Early life histories of fishes: Conversely, the maxillary barbel in Heptapteridae and Pimelodidae show positive allometric growth [ 14 ].

INPA1, Pectoral fin, when adpressed, reaching vertical through dorsal-fin spine, but not reaching pelvic fin.

The caudal fin in Lophiosilurus is formed and replaces part of the finfold during the postflexion stage. Skin of head and body with small appendages most evident as bony ridges.

The extreme condition in L. Accordingly, Lophiosilurus alexandri is an ideal species to observe the morphological changes during ontogeny, and to seek solid interpretations on the polarity of characters.

Lophiosilurus alexandri

However, the mouth shifts to a terminal position during the end of the yolk sac and early postflexion stages, and eventually becomes superior, prognathous by the end of the postflexion stage, a condition retained into adulthood. National Center for Biotechnology InformationU.

In the first apomorphic state, the upper and lower caudal-fin rays are approximately similar in length, and the second apomorphic state, the middle rays of the upper caudal-fin lobe become elongated. Primordial fin well developed in early stage of postflexion, surrounding the entire perimeter of trunk and tail; restricted to posterior regions of adipose and anal fins after day