Ph.D. Herrera-Cisterna, Guillermo

Larval development and shape ontogeny of the kelpfish Myxodes viridis (Clinidae) are described for the first time. A total of 214 individuals ranging between 3.51 and 23.09 mm standard length collected off central Chile were assessed employing classic and geometric morphometrics, illustration with camera lucida and a double-staining technique for cartilaginous and bone structure observation. Based on characteristics such as yolk sac presence and fin formation, six stages of larval development were differentiated: yolk sac, preflexion, flexion, early postflexion, late postflexion and juvenile. Shape changes during development are subtle and occur smoothly, being more significant in the head and preanal length, and ontogenetic allometry accounts for almost 15%. Cartilage formation takes place first at the branchial arches and cranium; then hypural, haemal and neural arches are consecutively formed. Bony structure ossification occurs late in the development. Vertebral centra ossify directly, without cartilaginous matrix replacement.

The finding of a late flexion cetomimid specimen of 24.6 mm body length (BL), plus a caudal streamer of 5.7 mm, collected in the southeastern Pacific near the Juan Fernandez seamounts (33.565°S; 77.710°W), is reported. The specimen was in good condition, almost fully pigmented, covered by small melanophores from the head to the caudal streamer, where the pigmentation is denser. It possesses an upturned mouth, developing pelvic fins with a high insertion, 14 dorsal and 15 anal fin rays, 7+7 principal caudal fin rays, ca. 54 myomeres, and a preanal distance of 75% BL. Based on the available information, the specimen can be tentatively ascribed to a species of Gyrinomimus or Cetomimus.