Taranis:
wrong, poland, lithuania, latvia and estonia where never part of Sarmatae
@ Sile, primarily: yes, the area of "Sarmatia" (in the Graeco-Roman sense) included approximately the area described, and this was purely a geographic term, as the ethnic groups were of different
Indeed, the area was called Sarmatia Europaea (there was also Sarmatia Asiatica located farther east, behind the Don River) and it was a purely geographical term. Germania or Germania Magna were also purely geographical terms, because they did not correspond to boundaries of Germanic-speaking peoples. There were many Non-Germanic peoples living within the area of Germania Magna (for example numerous Celtic tribes), as well as there were some migrating Germanic tribes which at some point in time lived beyond the boundaries of Germania Magna.
As I already wrote before in this thread, the area in question was called Sarmatia Europaea by ancient historians & geographers - for example by Poseidonius of Apameia, Pomponius Mela, Claudius Ptolemy, etc. Various authors saw the boundaries of Sarmatia Europaea - particularly its western boundaries with Germania Magna - differently. Poseidonius (born in 135 BC, died in 51 BC) saw the Germania-Sarmatia border along the Elbe River or somewhere between the Elbe River and the Oder River. Mela (died in 45 AD) saw it roughly along the Odra and the Lusatian Neisse Rivers (just like modern Polish-German border). And Ptolemy (born in 90 AD, died in 168 AD) saw the Germania-Sarmatia boundary along the Vistula River.
Please notice that between the 2nd century BC and the 2nd century AD the Germania-Sarmatia boundary was moving eastward in time. Maybe it is just a coincidence that those authors had different views on where the boundary was located, but maybe indeed there were population movements which were pushing the boundary in eastern direction - from roughly the Elbe/Oder to the Vistula in 300 years.
For the Urnfielders in that area (Eulau), its possible that they spoke either early Germanic (the "Germanic Parent language" in the sense of Euler) or an early Celtic, but we ultimately don't know for certain (though both a probable) because these people were illiterate.
Germanic language emerged in Scandinavia roughly during the Nordic Bronze Age, according to the most commonly accepted theory at least. So Corded Ware people from Eulau didn't speak Germanic, because they lived in a different geographical area and in a different time period.
R1a obviously was in these areas before Slavs but those were different subclades of R1a. For example R1a Z284 which was characteristic of Proto-Germanic population apparently. Do you have data on types of R1a subclades in different regions of Germany and Austria today?
R1a L664 that you mentioned is not found in Eastern Germany and in Austria today (not in high frequencies at least).
AFAIK great majority of R1a in Germany-Austria today are typically Slavic subclades. Especially West & South-West Slavic ones.
Also areas with highest frequency of R1a in Germany & Austria are the same areas which at some point of history had predominantly Slavic population. Though of course after WW2 there were huge population movements (expulsion of easternmost Germans), which contributed to the territorial dispersion of R1a over
entire Germany. I'm sure that large part of R1a in modern Western Germany came during and after the end of WW2. A lot also came with Polish immigration. Not to mention internal migrations from Communist Germany to West Germany in the second half of the 20th century.
My point merely is, if you posit the existence of some extinct, altogether separate branch of Indo-European (for the Lusatian culture, or the Urnfield culture), you need to demonstrate that from some corpus of lexical items you find somewhere.
There are many toponyms in modern territory of Poland which are of unknown or seriously disputed linguistic origin. For example Vistula and Oder are among such unclear toponyms (just to mention the two largest rivers in Poland). It is possible that these toponyms come from an extinct Indo-European language. Though it is also possible that some of them are Pre-Indo-European in origin (this is sometimes claimed for Vistula).
Later I will try to find and post here something more about those hypothetical Venedic-speaking peoples.
It is not only my hypothesis - there were scholars who proposed the existence of a Venedic branch of Indo-European languages. They are hardly the only extinct branch of IE languages - other of now extinct branches of Indo-European languages were for example: Sorothaptic, Ligurian, Phrygian, Dacian, Thracian, Lusitanian, maybe also Illyrian (because not everyone agrees that Albanian language is a direct continuation of Illyrian languages).
and early Slavic (the Savari, perhaps?).
They were called the Stavani (Stavanoi) by Ptolemy. Maybe another source calls them the Savari?
Ptolemy also records another tribe which could very likely be Slavic-speaking, the Slovenoi.
Ptolemy wrote that they lived much farther east than the Stavanoi, because along the Volga River:
Souobenoi, Sloveni (Greek: Σουοβενοι) - according to Ptolemy (around year 150 CE) a tribe living at the Volga River (Latin: Rha). Recording ou means phonteically a sound similar in pronunciation to English w, while Greek β can be read as v. This is why their name should be pronounced as Słovenoi (in phonetic recording [swovεnoɪ]). There exists a hypothesis equating this tribe with Slavs, supported by similarity to the oldest own name of Slavs from Slavic own written texts - *Słoveni [1] or Slověni [2].
[1] Gołąb, Zbigniew (1992).
The Origins of the Slavs: A Linguist's view. Columbus: Slavica Publishers, 1992
[2]
http://grzegorj.w.interia.pl/lingwpl/nazwy1.html#slowianie