Larval and osteological development of the mote sculpin (Normanichthys crockeri) (Pisces:Normanichthyidae) from the Independencia Bight, Pisco, Peru

Development of larval Normanichthys crockeri from Bahia Independencia, Pisco, Peru is described and illustrated. 3124 specimens were collected with plankton nets in 2000; a developmental series of 66 individuals (1.9-20.5 mm) from recently hatched larvae through transformation was assembled using general morphological features and pigmentation patterns. Cleared und stained specimens were examined for meristic and osteological development, some osteological characters are detailed. Normanichthys crockeri hatches at approximately 1.8 mm. Notochord flexion begins at ca. 6.2mm and ends at ca. 9.0mm, and transformation occurs at ca. 20.0mm BL. The most important diagnostic features of the larvae include early development of large, lightly pigmented pectoral fins, and early dorsal midline pigment on the trunk and tail which decreases gradually with development until the beginning of the flexion stage and does not reappear until the end of postflexion stage. Ventral pigment occurs along the midlines of the abdominal and postanal regions. Preanal finfold pigment is present until late postflexion stage. Pigment always is present at the angular, on the caudal region, and usually at the cleithrum. Larvae are moderately slender with a preanal length roughly half of the body length (ca. 40-53% BL). They have I,5 pelvic-fin rays, 7+6 principal caudal-fin rays and 36-37 myomeres (11-13+24-26, usually 13+24). Cleithrum, bones of the jaws and operculum are among the first to ossify, vertebrate appear at ca. 5.0mm NL and sequence of development is from anterior to posterior. The pectoral fin appears first, followed sequentially by the caudal fin, second dorsal and anal fin which form concurrently, first dorsal fin and pelvic fin.