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Gayana (Concepción)

versión On-line ISSN 0717-6538

Resumen

HERNANDEZ, Sebastián; LAMILLA, Julio; DUPRE, Enrique  y  STOTZ, Wolfgang. EMBRIONARY DEVELOPMENT OF THE REDSPOTTED CATSHARK Schroederichthys chilensis (Guichenot, 1848) (CHONDRICHTHYES: SCYLIORHINIDAE). Gayana (Concepc.) [online]. 2005, vol.69, n.1, pp. 184-190. ISSN 0717-6538.  http://dx.doi.org/10.4067/S0717-65382005000100025.

The present study describes the embrionary development of the redspotted shark, Schroederichthys chilensis, through observations of the external morphology of the eggs capsules, embryo morphology and measurement of gestation time. Sixty egg capsules were collected in the locality of Chungungo (IV Region, Chile). Two additional capsules were laid by a female kept in captivity. Eggs capsules were described based on morphometric measurements, coloration, texture and presence of respiratory fissures. For the determination and description of the embryonic morphology, embryos extracted from the collected capsules. For the determination of the gestation time 15 capsules with alive embryos were observed through a transparent window on the wall of each capsule. The eggs capsules are rectangular and they have two anterior prolongation called "filaments ovisac" and two posterior called "tendrils". The recently eggs capsules laid are brown or green opaque in coloration, partially smooth and sticky in texture and closed respiratory fissures. The eggs capsules with embryos in advanced stages are dark brown, flat texture and respiratory fissures open. Six stages of embrionary development were determined on the basis of the following diagnostic characters: viteline sac without embryo, pharyngeal clefts, gill filaments, differentiation of the fins from the dorsal and fold ventral ridge, spines on the tail, row of dorsal spines and pigmentation. The gestation time is 211 days at temperature of 11,5-15,8° C

Palabras llave : Development; embryos; egg capsules; catshark; Chile.

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