Introduction - Genetic Sex Differentiation in Fish - page 11

Table 5. Ontogenetic pathways of sex differentiation in diandric protogynic hermaphrodites

Species/References Reported observations

Labridae
Halichoeres poecilopterus
Kobayashi and Suzuki (1994)

Early gonads with many oocytes. Differentiates into
intersex gonad; of the 14 intersexes, 6 differentiate
into testis of primary males and others into functional
females, from which secondary males subsequently arise

Suezichthys gracilis
Kobayashi (1999)

Early ovarian gonad. Differentiate into intersex gonad.
Half of them differentiate into testis of primary males and
others into ovary of females, from which secondary males
arise

Sparidae
Pagrus pagrus
Kokokiris et al. (1999)

Intersexuals with ovary or undifferentiated gonad.
Differentiates into ovary and testis of primary male. From
females, secondary males arise. Delimited gonad. Sex
ratio 1♀ : 1♂. Transitional 4.4%

Boops boops
Monteiro et al. (2006)

Males and females are suggested to arise from juvenile
hermaphrodites . Majority of males originate early but
some secondary males from sex changed females. Sex
ratio 0.6♀ : 0.4♂. Transitional 5-18%

Serranidae
Epinephelus coioides
Liu and Sadovy de Mitcheson
(2009)

Undifferentiated gonadal primordium develops ovarian
lumen. Meiotic oocytes are then formed. Differentiates
into ovary, and subsequently to bisexual phase, the
Juvenile hermaphroditism . Differentiates into functional
ovary and testis in primary male. Secondary males arise
from females

E. akaara
Tanaka et al. (1990)

Commence with immature ovaries. Differentiates into
bisexual gonads, subsequently into ovaries and testes of
primary males. Females change to secondary males

testis occurs during the early juvenile stage, as in D. rerio or at puberty,
as in Dascyllus fl avicaudus (Table 3). The type 4 juvenile hermaphroditism
represents the ancestors, from which the protogynics have been derived. The
genus Dascyllus comprises of 10 species; D. fl avicaudus, D. albisella and D.
trimaculatus represent juvenile hermaphroditism, while D. reticulatus and D.
marginatus are protogynics and D. aruanas is an Okinawan hermaphrodite.
Thus the damselfi sh Dascyllus provides an excellent system for a study
of the evolution of protogyny (McCafferty et al., 2002). Likewise, type 3
secondary gonochores seem to be the ancestors, from which the diandrics
may have been derived.

Hermaphrodites: Gonochorism and simultaneous hermaphroditism are
evolutionary end points on a reproductive spectrum (Avise and Mank, 2009).
Incidentally, the hermaphroditic nematode Caenorhabditis elegans is a somatic
XX female, in which the loss of an X chromosome due to nondisjunction
results in the production of 5% XO males (Zarkower, 2006). It remains to