Yes, thanks for linking this image. I made it a while back and the "northernness" of the Iapodes is what planted the idea that there could have been two flows of peoples into south italy.
Then when I read this paper by Camilla Norman it was solidified:
"the theory of a Balkan heritage for the iapygians is based on little more than what has alreadybeen cited above: a handful of later comments by ancient authors, changes in the distribution, sizeand number of sites during the Middle and late Bronze age, and a number of perceived parallels inthe material cultures of either shore. Maria cecilia d’ercole’s contribution in mapping the pathwaysand movement of goods in the southern adriatic during archaic times has significantly helped fleshout the situation.7 recent work by croatian archaeologists who have documented sanctuaries on the
‘island bridge’ spanning from the dalmatian coast to the gargano peninsula in daunia,
in use fromat least the neolithic period, also adds considerable weight to the argument.8 the traffic was, however,no doubt two-way. the prevailing winds in the upper adriatic and a clock-wise current, in concertwith the ‘island bridge’, gave rise to strong maritime trade route that took in the daunians (furthersignposted by sea-faring craft incised on their stelae9) and Picinians on the west coast, and the
Japodians, histrians, liburnians and dalmatians (all ‘illyrian tribes’) on the north and east.10 it was likelymediated by the liburnians, whose thalassocracy it is alleged by appian was propped up by piracy(app. ill. 1.3)"
SOURCE:
https://www.academia.edu/33341054/I...toos_string_aprons_and_a_helmet?auto=download
This is very relevant to finding out the haplogroups of the Messapians proper as this northern flow connected with Dalmatia is unlikely to be the source of the Messapic language, which is most densely concentrated in Calabria.
As for the connection of the Thounatae with the name Dauni, this is Papazoglus suggestion of being possible, but it is clearly hypothetical and not as obviously true as Galabroi / Kalabri, Iapode / Iapyge, etc.