Larval development of the Pacific Sandperch (Prolatilus jugularis) (Pisces: Pinguipedidae) from the Independencia Bight, Pisco, Peru

Morphological development of larval Prolatilus jugularis from Bahia Independencia, Pisco, Peru is described. Two hundred and thirty-two specimens were collected with plankton nets in 2000; a developmental series of 40 individuals (2.5^25.9 mm: recently hatched through transformation) was assembled using morphological features and pigmentation. Prolatilus jugularis hatches at approximately 2.5 mm, notochord £exion begins at *5.7 mm and ends at *6.9 mm, and transformation begins at an unknown size between 14.2^20.3 mm (probably near 20 mm). Diagnostic features of the larvae include a robust body with large head bearing small preopercular spines that begin to form by late pre£exion stage; preanal length just under half of body length early in the pre£exion stage increasing to near two-thirds of body length in the post£exion stage; and pigmentation primarily on the snout, opercular region, dorsally on the head and gut, laterally above the hindgut, and on the ventral margin of the tail through early £exion stage. A broad mid-lateral stripe begins to form on the trunk and tail late in the £exion stage and dorsal pigmentation forms on the trunk and tail in the post£exion stage. Pectoral-¢n rays are ¢rst to begin forming, in midpre£exion stage, followed by principal caudal-¢n rays, then by pelvic-, dorsal- and anal-¢n rays which apparently begin to form simultaneously near the end of pre£exion stage. The dorsal ¢n is long and continuous, with III ^ IV short spines and 27^29 soft rays, the anal ¢n contains 21^23 rays, the ¢rst one or two of which may be spine-like, the pelvic ¢ns, with I spine, 5 rays, are below or slightly in front of the pectorals (18^20 rays), and there are 9 þ 8 principal caudal-¢n rays and 36^37 myomeres.