Año 1997, Número 11 – 135-144

Año 1997, Número 11 – 135-144

Ivanovic, M.L.; Brunetti, N.E. 1997.  Descripción de las mandíbulas de Illex argentinus y relaciones del largo rostral con la talla y el peso de los calamares.
Rev. Invest. Desarr. Pesq., 11: 135-144.
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A description of Illex argentinus beaks, made on the basis of qualitative and quantitative characteristics, is presented. Likewise the equations that represent the relationships between the rostral length of each beak with the mantle length and total weight of squids are proposed, as a tool for reconstructing them. A total of 291 squids, comprising the complete size range, from juveniles to adults, were analyzed for the latter purpose. The morphometric description was made on a total of 90 individuals from the Argentine Sea, taking the following measurements on each beak: rostral length, hood length, crest length, wing length and wing width. Results showed that I. argentinus beaks present the general scheme of that corresponding to the Ommastrephidae Family, to which this species belongs. The lower beak characteristically has a wide hood, with long rostrum and wings, and a notable knob situated on the basis of the mandibular angle. The crest is short and the lateral walls slightly long. A strong growth alometry between hood and crest in relation to the rostrum was detected. The upper beak also has a wide hood, with a long curved rostrum and small wings, whereas the crest and lateral walls are long. Hood growth in relation to that of the rostrum was detected to be alometric, but that corresponding to the crest was isometric. Pigmentation of both beaks intensified with growth, specially from 200 mm ML on.