This study reports for the first time a case of multiple morphological abnormalities in a blue shark Prionace glauca embryo collected on the Peruvian coast, southeast Pacific. External exploration and radiograph picture showed duplicated parts in the cephalic region (mouths and eye sockets) and trunk anomalies (thoracic lordosis and rolled caudal fin). The duplicate face parts in a single head seen in the embryo, suggest a diprosopia anomaly.
Algunas especies de batoideos poseen una cobertura dérmica con variaciones morfológicas utilizadas para taxonomía Esta investigación caracteriza morfológicamente las estructuras dérmicas de batoideos desembarcados en el litoral peruano, de acuerdo a las especies, zonas del cuerpo, etapa de desarrollo y sexo. Se analizaron 3 especies: Pseudobatos planiceps, Rostroraja velezi y Sympterygia brevicaudata, adquiridas de la pesca artesanal desde el norte al sur del país. Se identificaron tres tipos de estructuras: dentículos dérmicos, tubérculos cutáneos y espinas. Diversas estructuras dérmicas están presentes desde el nacimiento de los individuos. En Rajiformes, las diferencias entre sexos radicaron en la existencia de espinas malares y alares en machos. La presencia de poros en el lado ventral de la base de tubérculos y espinas de Rhinopristiformes, difiere de los Rajiformes, que presentan una cavidad donde se aloja la piel y se extiende hasta la base de la cavidad de la pulpa. Las diferencias en la morfología de estructuras dérmicas estuvieron relacionadas a las zonas del cuerpo evaluadas y a los patrones de cobertura dérmica entre especies. Además, estos resultados demuestran que la metodología utilizada en el presente estudio permite realizar una determinación a nivel de especie.
Shark skin is covered by small structures called dermal denticles whose functions are diverse, such as protection, bioluminescence, hydrodynamics, among other functions. These structures have a great variety of shapes and sizes, which can be a useful approach for specimen identification as diagnostic characters between species. The present study aims to describe the dermal denticles morphology of the broadnose seven-gill shark Notorynchus cepedianus, evaluating differences among life-stage (neonate, juvenile and adult), sex and body region (dorsal and ventral). For achieving it, 39 specimens were collected at six landing points along the Peruvian coast. The dermal denticles from two body regions(dorsal and ventral) were photographed, measured (length, width, angle and density), and described using a stereoscope. Dermal denticles measures showed significant morphological differences between body regions as well as stages of development, but not between sexes. The differences are: (1) Crown shape: as the individual grows, it can be seen that the cross shape is losing, (2) Crown cusps: cusps length varied according to the stage of each individual, it was also observed that the lateral cusps are larger in dorsal than ventral region, and (3) Union peduncle - crown: adult specimens and both body regions, the observed union was very dimly and it did not have a defined shape. On the whole, these reported variations in measured traits could be useful as diagnostic characters to identify the stage of development at which the landed and marketed specimens are found.
Records about morphological abnormalities in rays of the genus Myliobatis are scarce worldwide. In the present study, three specimens exhibiting different malformations were identified during the monitoring of the reproductive biology of the Chilean eagle ray Myliobatis chilensis, conducted from 2017 to 2018 in the fishing port of Salaverry (northern Peru). The identified specimens included: (i) a female with split pectoral fins, (ii) a male with an unfused-to-the-head pectoral fin, and (iii) a female with a short and thick tail. Here we report and discuss the implications and likely causes of these first three cases of morphological abnormalities in M. chilensis from the western Pacific.
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