Well I guess this is a variation between the marble motoro varient and the normal motoro? Then again, using spines as a indicator between different species may not be as accurate as we previously thought. As stated in another thread, rays of the same species can have great variations in this aspect. It's probable that the spines of rays are similar to body hair in humans to a certain extent. Some people are hairy while others are not. Though very distinct spine differations between species do exist at large (eg. spine differentiation between P.leopoldi and P.henlei). Though not 100% accurate, I think dorsal patterns are a better indicator. Boesemani in general have large orange irregular spots and a distinctive "chained spots" background. Just my personal opinion.
>Potamotrygon Boesemani Profile<
- Thread starter calgaryflames
- Start date
Differentiation of species within the Potamotrygon genus is rather tricky, here is the article describing P. boesemani published in neotropical ichtyology (2008): http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000100001
They only use morphological data in their paper as you traditionally do. However to distinguish Potamotrygon species from morphology and color patterns is rather tricky (as you so well state above) since they are very plastic in their appearance. If you look at fossil data, the genus Potamotrygon seem to appear about 20 million years ago, which is very young in evolutionary perspectives. And if you look at molecular data several of the species we have today, seem to belong to the same species or be very very closely related. It is possible that the variety of species in south america is rather a set of well separated populations of the same or a few species that is undergoing speciation right now. This would explain why 'hybridizations' with fertile offspring still is possible and so common in aquaria.
/David
They only use morphological data in their paper as you traditionally do. However to distinguish Potamotrygon species from morphology and color patterns is rather tricky (as you so well state above) since they are very plastic in their appearance. If you look at fossil data, the genus Potamotrygon seem to appear about 20 million years ago, which is very young in evolutionary perspectives. And if you look at molecular data several of the species we have today, seem to belong to the same species or be very very closely related. It is possible that the variety of species in south america is rather a set of well separated populations of the same or a few species that is undergoing speciation right now. This would explain why 'hybridizations' with fertile offspring still is possible and so common in aquaria.
/David
Could also be a location thing.motoro are found through out most of the basin.mine did not have spines running down their side of the tails nor does any i have seen or looked up online?
So your saying the marbles you have maybe similar . What other way would their be to distinguish the species apart. My boesemani has a very large head and spiracles.much larger than any of the largest black ray species i have.i do not remember my pearls or any of my motoros having such features.it's very hard to capture I'n a photo but i will try and make a video
So your saying the marbles you have maybe similar . What other way would their be to distinguish the species apart. My boesemani has a very large head and spiracles.much larger than any of the largest black ray species i have.i do not remember my pearls or any of my motoros having such features.it's very hard to capture I'n a photo but i will try and make a video
Those spines also start about 1/3 or even 1/2 down the tail? It's a bit different.i have never seen motoro like these.maybe marble motoro is a different species???
And body got a pic of a pearl tail or can share the spine pattern
And body got a pic of a pearl tail or can share the spine pattern
The above pic shows a close up of one of my Pearll females.Here you can see the tail of this species is much thornier than what is found in Motoro but the most interesting thing is the spines run up the back and towards the head,i have no less than 7 adult\subadult pearls and they all have this trait.
Mshuangchao,like i've just mentioned all these Pearls have this spine arrangement but all are so different regarding dorsal pattern,to the untrained eye they could be mistaken for different species........apart from the spines which are same on them all.
The thorns on this ray are much heavier towards the end of the tail.
Mshuangchao,like i've just mentioned all these Pearls have this spine arrangement but all are so different regarding dorsal pattern,to the untrained eye they could be mistaken for different species........apart from the spines which are same on them all.
The thorns on this ray are much heavier towards the end of the tail.
P. motoro have been suggested to either be a complex of similar species or P. motoro and a few other species together represent one highly polymorphic species. This is after that they have looked at DNA sequences from these species. The present descriptions of the different species have been done using mostly morphological data as with the description of P. boesemani above. The morphological studies does not take into account that different populations may represent very different varieties but of the same species which molecular data would reveal. Some thing that is for sure is that it is not as simple as the picture is today when it comes to the species composition of the Potamotrygon genus.
We have to remember that the species concept is something created by us and real life borders between species are not as clear cut as systematics would like it to be.
We have to remember that the species concept is something created by us and real life borders between species are not as clear cut as systematics would like it to be.
