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Histological study of the development of the embryo and early larva of Oreochromis niloticus (Pisces: Cichlidae)
Author(s) -
Morrison Carol M.,
Miyake Tsutomu,
Wright James R.
Publication year - 2001
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/1097-4687(200102)247:2<172::aid-jmor1011>3.0.co;2-h
Subject(s) - biology , blastula , hatching , yolk sac , anatomy , embryo , human fertilization , larva , integumentary system , embryogenesis , zoology , ecology , fishery , gastrulation
The developmental stages of Oreochromis niloticus are similar to those described in other mouth‐breeding tilapias except that, as in zebrafish, no cavity was found in the blastula. Variation in the rate of development of the embryo and larva of O. niloticus was found within a clutch of eggs as well as between clutches. Hatching glands are described for the first time in tilapias. They are widely distributed within the ectoderm covering the head, body, tail, and surface of the yolk sac near its attachment to the embryo. Timing of larval development is similar to that in other mouthbrooding tilapias, but is slower than that found in substrate‐spawning tilapias. A pneumatic duct connects the swimbladder to the digestive tract and swimbladder inflation and initiation of feeding occurs at about the same time. The digestive tract of the larva 8 and 9 days after fertilization is similar to that found in the adult, except that there are no digestive glands. An endocrine pancreatic islet was first seen 76 h after fertilization. A prominent thymus gland is present at 100 h. Hematopoietic tissue develops in the vicinity of the pronephros during early larval development. A spleen develops later, 7 days after fertilization. J. Morphol. 247:172–195, 2001. © 2001 Wiley‐Liss, Inc.