Journal of Plankton Research Vol.25 no.3 pp.279-290, 2003
© Oxford University Press 2003
Larval and osteological development of the mote sculpin (Normanichthys crockeri) (Pisces:Normanichthyidae) from the Independencia Bight, Pisco, Peru
1 Alfred Wegener Institute for Polar and Marine Research, Columbusstrasse, D-27568 Bremerhaven, Germany, 2 National Marine Fisheries Service, Southwest Fisheries Science Center 8604 La Jolla Shores Drive, CA 92038, USA and 3 Center for Tropical Marine Ecology, Fahrenheitstrasse 6, 28359 Bremen, Germany
* Corresponding Author: jvelez{at}awi-bremerhaven.de
Ontogeny of Normanichthys crockeri is described and illustrated based on 66 specimens (1.9–20.5 mm; including recently hatched larvae through to the transformation stage) collected in Bahia Independencia, Pisco, Peru. Larvae hatch at approximately 1.8 mm, undergo notochord flexion at ca. 6.2–9.0 mm, and transform to juveniles at ca. 20.0 mm. Larvae were identified by the series method, using a combination of meristic and developmental characters that permitted definitive identification. Diagnostic features of the larvae include early development of large, lightly pigmented pectoral fins; early dorsal midline pigment on the trunk and tail which decreases gradually to none by the beginning of the flexion stage and does not reappear until late postflexion stage; and pigment ventrally, on the midlines of the abdominal and postanal regions, on the preanal until late postflexion stage, at the angular, on the caudal region, and usually at the cleithrum. Larvae are moderately slender with preanal length roughly half of body length (ca. 40–53% body length). They have I,5 pelvic-fin rays, 7+6 principal caudal-fin rays and 36–37 myomeres (11–13+24–26, usually 13+24). The cleithra and bones of the jaws and opercular series are among the first to begin ossifying. The anterior vertebrae begin to ossify at ca. 5.0 mm and addition is posteriorly. The pectoral fin is the first to begin ray formation, followed sequentially by the principal caudal-fin rays, second dorsal- and anal-fin rays (forming concurrently), spiny dorsal-fin rays, and pelvic-fin rays.