Biology Reference
In-Depth Information
Table 3.
Ontogenetic pathways of sex differentiation in different types of secondary
gonochores
Species/References
Reported observations
Type 1
Pseudorasbora parva
Takahashi and Maeno (1986)
Juvenile hermaphroditism
is rather obscure.
However, a testicular cavity, homologous to
ovarian cavity, is present. Oogenesis within testis
Carassius auratus, Rhodeus ocellatus
ocellatus
(see Takahashi and Maeno,
1986)
Vestigeal ovarian cavity becomes not detectable,
as testis grows over it
Nemipterus bathybius, N. virgatus
Takahashi et al. (1989)
Rudimentary hermaphroditism
Ovarian cavity
persists as vestige in testis. Functional testis
substantially ovarian. Delimited gonad
Type 2
Pachymetopon grande
Buxton and Clarke (1992)
Rudimentary
hermaphroditism
.
Non functional
dominant ovary and narrowly ridged testis.
Delayed differentiation into functional ovary
and testis. Delimited gonad
Pterogymnus laniarius
Booth and Buxton (1997)
Non functional intersex
.
Dominant ovary and
posterolaterally ridged testis. Delimited gonad
from which ovary and testis arise rather lately
Type 3
Elacatinus evelynae, E. illecebrosus
Cole (2008)
Gobiids. Transient ontogenetic expression of
bisexual gonads prior to differentiation into
males and females
Mycteroperca rosacea
Erisman et al. (2008)
Commence as immature bisexuals. Some directly
differentiate into females, while others remain
immature bisexuals, from which females and
males arise. Sex ratio 1♀ : 1♂
Epinephelus striatus
Sadovy and Colin (1995)
Commence as females and bisexuals. Females
arise directly as well as from bisexuals. Males
arise only from bisexuals. Dygynic? Sex ratio
changes from 0.71♀ : 0.29♂ to 0.5♀ : 0.5♂ with
increasing body size from 42 to 52 cm
Type 4
Barbus tetrazona tetrazona
Takahasi and Shimizu (1983)
Juvenile intersexuality
.
All gonads initially
with ovary. Intersexual gonads degenerate in
presumptive males between 45 and 50 dph.
Ovarian cavity persistent. Sex ratio 1♀ : 1♂
Danio rerio
Uchida et al. (2002)
Juvenile hermaphroditism
.
All gonads initially
with ovary. Intersexual gonads degenesate by
apoptosis in presumptive males between 15 and 27
dph. Ovarian cavity persistent. Sex ratio ≈ 1♀ : 1♂
Dascyllus albisella, D. fl avicaudus,
D. trimaculatus
Asoh et al. (2001), Asoh (2004), Asoh
and Kasuya (2002)
Undifferentiated gonads differentiate into
ovaries with oocytes developing upto cortical
alveolar stage. Now many ovaries develop into
matured ones while others into testis, following
degeneration of oocytes but with persistent
ovarian lumen
