A
Novel Reproductive Mode in Frogs: A New Species of Fanged Frog with Internal
Fertilization and Birth of Tadpoles
Djoko
T. Iskandar, Ben J. Evans, Jimmy A. McGuire
Researchers have found a new species of
frog, Limnonectes larvaepartus that
live in Sulawesi Island, Indonesia. This species is especially interesting to
study because scientists have found that L.
larvaepartus uses internal fertilization as their reproductive mode. Not
only that, but they give live birth to tadpoles not froglets.
Researchers first discovered this rare
reproductive mode while conducting a different study when they noticed movement
in the abdominal wall of the species and discovered tadpoles inside of the
specimen. One of the specimens even gave live birth to tadpoles in one of the researchers
hand. The article said, “we have either observed tadpoles in the oviducts or
direct-birth of tadpoles on 19 occasions”. Researchers had observed great
diversity throughout the genus Limnoenectes and were interested in continuing
in depth research about this genus because of its wide variability. L.
larvaepartus is distinguishable from other species in its genus by “body
size, coloration, tympanum size, and extensive hind foot webbing”. They usually have a brown dorsal
coloration and cream venter. L.
larvaepartus are mostly terrestrial and can be found in rocky, leafy, or
grassy areas. The females can produce up to 100 eggs, which develop in the
oviducts into tadpoles and then are released as tadpoles at birth. The mother
does not provide direct forms of nutrients to the tadpoles, but the inside of
the oviducts is lined with a yolk to provide the nutrients.
The most common reproductive mode in
frogs is external fertilization through amplexus. Although rare, there are
other frogs that have shown to have internal fertilization, but they either “give
live birth to froglets or deposit fertilized eggs”. Furthermore, as we have learned frogs commonly display many
types of parental care such as egg attendance, egg carrying, tadpole
attendance, tadpole transport, tadpole feeding, and froglet transport. It is
also common for frogs to differ in timing of development, some metamorphosing
later when they are bigger, or vice versa. This specific species is important
to study because it is much less common to see internal fertilization used within
the Anuran family. Some of the documented genera of anurans that display
internal fertilization with egg retention and birth to froglets include,
Nectophrynoides, Nimbaphrynoides, and Eleutherodactylus. The genus Limnonectes
shows internal fertilization with birth to tadpoles, even more rare than the
other type of internal fertilization seen prior to the discovery of this
species.
This study was done by observing more
than 100 frogs from Limnonectes found across the Northern Peninsula of the
Sulawesi Island. The specimens were caught by hand, sacrificed, and observed at
the Museum Zoologicum Bogoriense. They examined the frogs to determine sex and
measured different parts of their body. Not a lot of research has been done on
this topic specific to this species. Researchers have hypothesized that the
reproductive mode of L. larvaepartus may
be either direct birth of tadpoles, or direct birth of froglets. Since
researchers have yet to discover this species carrying froglets, the
observations they have mad so far have suggested the direct birth of tadpoles
as the reproductive mode. Adaptive plasticity has been observed in many frog
species, but usually only while they are in the froglet stage. L. larvaepartus suggests that they may
be born after they eat their supply of nutrients while inside their mother and
that they could not stay inside her until they became froglets as other species
could. Further experiments should be done to confirm the researchers hypothesis about the new mode of reproduction.
Iskandar, D. T., Evans, B. J., & McGuire, J. A. (2014).
A Novel Reproductive Mode in Frogs: A New Species of Fanged Frog with Internal
Fertilization and Birth of Tadpoles. Plos ONE, 9(12), 1-14.
doi:10.1371/journal.pone.0115884
1 comment:
Amazing!
Post a Comment