What happened with the introduction of κόνικλος during the Koine period? Was, perhaps, the meaning of λαγώς reduced to only the larger animal, or was the smaller species not indigenous to Greece?
It’s actually a loan word from Latin cuniculus, itself apparently a loan word from Iberian Celtic. It’s notoriously difficult to pin down species designations in ancient authors, who simply don’t use terminology in what we consider to be a scientifically precise way.
Does Latin distinguish “hare” from “rabbit”?
Yes, cuniculus,i vs lepus,ŏris.
Hi, Stephen,
It has been alleged that Koine tends to replace irregular/complicated third declension nouns with nouns that are more simply/easily declined. ναῦς → πλοῖον; οὖς → ὠτίον; ὗς–> χοῖρος. Allegedly the trend was driven by speakers for whom Greek was a second language, and for whom easier words would be preferred.
Κράτιστε φωσφόρε!
ἐξεπλήχθην βλέπων τοσοῦτον καλὼς ἔγραψας ὧδε τὴν Ἀγγλικὴν. ἐμηκυνθήσατο γὰρ ὡς σχέδον πεντήκοντα λεξέων ἡ γραφή σου. ὡς πεπαιδευμένος μὲν περιείληφας τὸ ἑτερόκλιτον whom παρὰ τὸ who. συμβουλεύω σοι δὲ προσυπογράψαντι λαβεῖν περισσότερα παραδείγματα καὶ σχόλια διαρρήδην εἰπεῖν, καὶ κατὰ μικρὸν καὶ ἄλλας λέξεις προστιθείης τῇ γραφῇ σου. τὸ λοιπόν, οὐ μόνον οἱ ἑλληνισταὶ, οἶμαι, ἀλλὰ καὶ τῶν Πανελλήνων οἱ ἀγράμματοι.
Does Latin distinguish “hare” from “rabbit”?
anphph has already answered this, but you may also want to check with the great Roman Legion-Hare: http://www.dailymotion.com/video/x3djwy5.
In that cartoon, the red-haired Roman called the hare a “rabbit”. (Besides that he also called the horse a “mule”). One wonders, that if with that colour hair, he might not but have been an Iberian Celt, not yet realising that his newly aquired tongue had words to differentiate them.
Yes, things get complicated when we consult the original sources 
.
I like your theory that the red-haired Roman may be an Iberian Celt. But the question of his ethnic identity gets even more complicated when you consider that his name is Yosemite Sam (Yosemitus Samuel).
Looking for complexity. I’m only aware of two complicated theories of migration involving possible Celtic people:
- The Solutrean hypothesis is premised on an assumed East → West migration and even if somebody was to suggest a relationship with the indigenous people’s of the American Pacific North West, how did the name get to Rome?
- The similar theory of East to West un-documented, but perhaps archeologically traceable migration of Celtic people(s) holds that red-head New Zealanders, who the theory holds that the pre-Maori settlers of New Zealand (identified in that theory with the Patupaiarehe of Maori legend) are Celts who arrived from the Eastern areas of Celtic settlement in the old world via a series of tribulations in meso-America.
Neither of those could account for that guy’s Jewish first name though. 
Aelian suggests that κόνικλος is a type of λαγώς.
μεῖζόν τι ἢ σιγὴν οὐκ ἔχω εἰπεῖν.
But:
- Two more (equally dubious) examples: ὄρνις → πετεινόν, οἶς → πρόβατον.
- You would know better than I would, but I think AG words difficult to decline tend not to survive into Demotic, at least as the most common words used. Cf. MG κουνέλι
As powerful a word nowadays as the Spartan king’s “if” in its day.
- Two more (equally dubious) examples: ὄρνις → πετεινόν, οἶς → πρόβατον.
I read somewhere that a feature of the formation of a Koine - a form of the language for a non-native population to use - is the addition of classifiers. Something like that I might decide to say, “butcher’s shop”, rather than to the “butcher’s” when I was talking to somebody who I suspected might not be familiar with the word “butcher”. Both of your examples are of that sort, only that the classifier has been omitted. The “flying (animal)” and the “(animal that) follows the one in front” can more easily be understood by analogy than the specific lexical units that need to be learnt individually, and which contain no hints.
- You would know better than I would, but I think AG words difficult to decline tend not to survive into Demotic, at least as the most common words used. Cf. MG κουνέλι
Because the accusative of third declension nouns is often in alpha, that neatly forms the basis of a more regular declension in many cases, eg. ο αγώνας. The diminultive is a more regular form too. This is actually a huge topic. There is a great cover-up and rejection of Turkish elements in the language during the formation of the Modern Greek venacular.
[μσν. κουνέλι < ιταλ. (διαλεκτ.) cunelo, πληθ. cuneli που θεωρήθηκε ουδ. εν.]
Byzantine κουνέλι < Ital. (dialectical form) cunelo, pl. cuneli which was seen as a neuter singular
Your κουνέλι is etymological related to Italian, rather than being internally derived from the Hellenistic κύνικλος / κόνικλος (< Latin).