Early ontogeny of Tropheus moorii Boulenger 1898 (Pisces, Cichlidae, Lake Tanganyika) in laboratory conditions

Polish Journal of Natural Science 03/2008; 23(4):888-903. DOI: 10.2478/v10020-008-0072-5


In this work were shown some crucial moments in early Tropheus moorii development (for example: beginning og exogenous feeding period, end of endogenous feeding period, time of finish fins development and others). Fertilized eggs, obtained after natural spawning from females of Tropheus species kept in tank, were incubated in laboratory conditions. Hatched embryos were reared in incubation tank, in constant temperature, until resorption of the yolk sac and finish fins development. Embryos were fed ad libitum with live Artemia nauplii. In Tropheus, the fins became fully developed and the yolk sac supplies depleted on the same day, 25th since the mating. Since this species keeps its offspring in the mouth fo 30-35 days (Yanagisawa, Sato 1990), the young stay in they shelter for another on to two weeks. When they are let out for the first time, they are in advanced stage of their development, mature enough to live like the adults of their species. Since their yolk sac supplies are depleted before the termination of parental care period, it is obvious that they must be intrabucally fed in this time. It is confirmed by the fact that in aquarium conditions incubating females pick the food particles as the non-incubating females do. The food had been found on a regular basis in incubating females mouths when acquiring eggs and embryos for observations. Since the young Tropheus already can ingest exogenous food while being still in mother's mouth, it is on purpose to feed crushed food to the incubating females in aquarium conditions.

Download full-text


Available from: Andrzej Mamcarz
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The larvae of the fish Astyanax mexicanus transiently develop a flat and adhesive structure on the top of their heads that we have called "the casquette" (cas, meaning "hat"). We hypothesized that the cas may be a teleostean homolog of the well-studied Xenopus cement gland, despite their different positions and structures. Here we show that the cas has an ectodermal origin, secretes mucus, expresses bone morphogenic protein 4 (Bmp4) and pituitary homeobox 1/2 (Pitx1/2), is innervated by the trigeminal ganglion and serotonergic raphe neurons, and has a role in the control and the development of the larval swimming behavior. These developmental, connectivity, and behavioral functional data support a level of deep homology between the frog cement gland and the Astyanax cas and suggest that attachment organs can develop in varied positions on the head ectoderm by recruitment of a Bmp4-dependent developmental module. We also show that the attachment organs of the cichlid Tilapia mariae larvae display some of these features. We discuss the possibility that these highly diversified attachment glands may be ancestral to chordates and have been lost repetitively in many vertebrate classes.
    Full-text · Article · Oct 2010 · Proceedings of the National Academy of Sciences
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The larvae of aquatic vertebrates sometimes possess a transient, mucus-secreting gland on their heads. The most studied of these organs is the Xenopus cement gland. The tadpoles use it to attach to plants or to the water surface, supposedly to hide from predators and save energy before they can swim or feed. Moreover their gland, being innervated by trigeminal fibres, also mediates a locomotor stopping response when the larvae encounter an obstacle. We have described an equivalent organ on the head of the teleost Astyanax mexicanus, that we have called the casquette because of its shape and position on the larval head. The casquette is transient, sticky, secretes mucus, is innervated by the trigeminal ganglion, has an inhibitory function on larval swimming behavior, and expresses Bmp4 and Pitx1/2 during embryogenesis. Here we further discuss the nature of the equivalence between the frog cement gland and the fish casquette, and highlight the usefulness of non-conventional model species to decipher developmental and evolutionary mechanisms of morphological variations.
    Full-text · Article · Jan 2011 · Communicative & integrative biology