Morphometric Characterization of the Reproductive System of the Chilean Angelshark Squatina armata (Philippi, 1887)

Extensive fishing has caused a significant decline in the populations of the Chilean angelshark Squatina armata, yet limited information on the basic biology of the species presents an obstacle for science-based conservation and management policies. Here, we present a morphometric analysis of the reproductive system of S. armata. Seventy-six specimens were collected from the artisanal fisheries using bottom gillnets and trammel nets, targeting mainly elasmobranchs. We determined sex, total length, and external characteristics such as the presence or absence of semen, rotation of the gonopterygia, opening of the rhyphiodon, thorns on the pectoral fins of males, and mating scars on females. Paired t-tests and regression analyses were used to evaluate bilateral asymmetry in reproductive organs and the relationship between organ dimensions and total length. The analyses revealed directional asymmetry in both sexes, with the left ovary and uterus in females, and the left testis and epididymis in males, generally larger than the right counterparts. In addition, reproductive organ size increased significantly with total length. These results provide the first detailed description of reproductive organ morphology and asymmetry in S. armata, improving current knowledge of its reproductive development and providing baseline information for future reproductive and fisheries management studies.