Identification of citrus from Assam

[steffengot]

Hello everyone,

I would like your help in identifying a citrus (species?) from Assam. 
I found a picture of a to me interesting looking citrus species on a facebook group (for indentification of nativ plants in north-east India). I would like to attach the picture, however I received an error message (Error: This forum has exceeded its attachment space limit. Your file cannot be uploaded.). Without the picture its hard, but I give you already all information I got.
The citrus is apparently called: সোলেং টেঙা। in Bengali (Soleng Tenga). As english translation I get something like soleng sour. Its apparently a very sour fruit. The fruit grows on a high tree (several meters tall) in a garden in the city of Guwahati, which is the biggest city in Assam. The owner of the plant could just tell me that it seams to be an endangered variety and that he does not know any other name. The fruit itself contains lots of seeds and is according to him not really edible, since its so sour. 
I know now, that there are lots of different citrus varieties available in Assam and neighboring states. Its however very hard to get to know more about these fruits/plants. For me it looks like a sort of ugly lemon, but would be also a citrus medica variety or something totally different.

So maybe someone of you can help me or knows more about it. I also would like to attach the picture here, if possible. 

Thank you a lot for your help.

Best regards,
Steffen

[Laaz]

Looks like a pear lemon or citrus lumia.

Welcome to the forum. You you can upload photos to imgbb.com & post th links here.

[steffengot]

Thank you for your answer.
Here comes the picture:
ibb.co/QFhYGgL

From the shape it looks in fact like a lumia lemon, however seams the pear lemon to come from Italy and not to be a ‘wild’ lemon from
north-east india, in particular Assam. I will soon get more pictures from the tree and I asked also for a picture, showing the inside of the fruit.

[mikkel]

Citrus megaloxycarpa

due to this book Soleng Tenga is a type of megaloxycarpa

books.google.de/books?id=ET7G5hyVK90C&pg=PA17&lpg=PA17&dq=Soleng+Tenga&source=bl&ots=vlWdHNI7Va&sig=ACfU3U3nzc2ELZhCqXEhtnfsaA4t8gaUPg&hl=de&sa=X&redir_esc=y#v=onepage&q=Soleng%20Tenga&f=false

www.fruitipedia.com/2018/11/amilbed_citrus-megaloxycarpa/

[steffengot]

I think that was a good guess with the citrus megaloxycarpa. It really seams to be that kind of citrus. I mean some variety of it. Thank you a lot for your help.

[steffengot]

Here is another picture from the Citrus.



You still think it’s a citrus megaloxycarpa?