عنوان مقاله [English]
نویسندگان [English]چکیده [English]
This study was conducted to survey the body shape changes and development of external morphological characters of Angel fish (Pterophyllum scalare), during early development from hatching up to 51 days post hatching (DPH) using geometric morphometric technique. For this purpose, a total number of 108 specimens were collected. To extract body shape data, the left sides of the specimens were photographed using a digital camera. Then nine homologous landmark-points were defined and digitized on 2D pictures using tpsDig2 software. Landmark data after GPA, analyzed using Relative Warp Analysis. A cluster analysis was performed to identify clusters between age or size groups i.e. identifications of the larval stages. The results revealed that body shape changes of this species during early development are occurred in two phases, including (1) increasing body depth and length and depth of head and (2) increasing body depth, length of caudal peduncle and posterior displacement of eye that provide vital biological functions e.g. feeding, respiration and swimming according to their priorities. Based on the results of geometric morphometric analysis, the early development of Angel fish can be divided into five stages, including (1) Eleuthero-embryo (2) Propterygio larval (3) Pterygiolarval (4) younger juvenile and (5) juvenile that is in agreement with development of external morphology.