Please somebody tell that what was the surname or title of the Pandavas? Was it Chakraborty because they were also called "Chakraborty Samrat"?
The Surname is modern concept , in ancient times all the Dwijas (dwija jaatis) used to have similar surnames according to their varnas. When a dwija greeted somebody he used to recite adhivadan to the other respected one like a Bramhin would say
abhivadaye name (sharma) ahamasmibho (ManuSmriti 2.122)
The Sharma is to be replaced by
Verma for Kshatriyas and Guptas for Vaishyas. So In case of pandavas they would've acknowledged themselves as
abhivadye Yudhishtir Verma Ahamasmibho
In other words they would take verma as their last name, since it is vedic convention.
About their family lineage they were descendants of Puru Dynasty which was a chandravanshi Dynasty. So basically Pandavas have a Generic identity as Chandravanshi Kshatriya Kaurava /Puru vanshi which ended up with nanda dynasty
Important the abhivadan is not limited to the lines manusmriti mentions it includes recitation of your gotra pravaras/Raja Rishi lienage etc.(Raj Rishi is used for Kshatriyas instead of Normal Rishis). That is why I have posted another question on abhivadan/abhivadyae.
Chakraborty or Chakravartin is not a surname rather it is a word to depict a great/righteous ruler.
More Information on Kuru Kingdom
I am not sure if folks in that time had more of surname as such.. Like before last 100 years, families would be known by some "family/caste/denomination" names.. I remember my family had one of that family name.. For many families, those names still carry forward as a proper last name/surname and for many others, they chose another good surname ..
To attempt an answer for you - I think those times Kings had more of "dynasty" name as family name rather than first name and last name to fill the forms.
Yayati was the King who had 2 sons - Puru and Yadu and Yadu was elder and Puru was younger... legends follow that the "Puru" was the winner of the throne and his sons and grandsons rules the Dynasty of "Hastinapur" whereas "Yadavs" never took over.
So years and years after, in times of Pandavas and Kauravas - all descendents of Yayati's younger son -"Puru" are known to be "Purus"
So I would say - "Yudhisthir Puru, Bhim Puru, Arjun Puru, etcc :)
~~~ This is a view of what I understood from various sources including own life experiences, there may be better explanation/justification.
Kuru is the name of the clan to which Kaurav's and Pandav's belonged. King 'Yayati', their forefather and ancestor was the descendent of Lunar Lineage or Chandra Vansha. During that time surnames were not used, rather "Varna" was used to describe the caste/community of a tribe to whom one belong. The Kuru clan, thus belonged to 'Kshatriya' Varna. Also, pls note that during the 'Yagna' or Marriage the clan was known by the Guru or Maha-rishi they followed. Guru Dronacharya, although their chief Guru/Seer/Sage of Kuru Vansh or Kul, but he was only their Teacher and not their Kul Guru. All the current descendent of Kuru vansh has only these 2 Surnames - Tomar/ Tanwar and 2 Gotras - Attri or Vyaghra - Both were their Kul Gurus. Sage Attri was Kul Guru of Yayati and Sage Vyaghra was Kul Guru of last Kuru's. Most of the today's clan of Kuru Vansh is found in Haryana, Rajasthan, Delhi, Madhya Pradesh and Uttar Pradesh.
I think Chakraborty is right because this is truth that the Pandavas were also called Chakraborty Samrat. My guru told me that Chakraborty was non-other than the surname of the Pandavas. Chakraborty families are Brahmins and also Kshatriyas and Pandavas too. I am himself from a Chakraborty family,so I know that Pandavas were my forefathers. Believe me and this is truth!