One thing that fascinates me are latin 1st declension masculine occupational nouns: pirata, nauta, poeta... Both pirata and poeta at least, take "il" in italian. Nauta it seems, did not survive.
I've heard it explained by saying that "they're typically men's spheres" as rationale from my brief exposure to the language, but this seems deeply unsatisfying for a variety of reasons - id est, in comparison to something along the lines of loanword/archaism/evolution of root/evolution of grammatic gender.
Another factor is that all three of those nouns are loanwords from Ancient Greek, which had quite a few 1st declension nouns that are masculine. Agricola (“farmer”) is an example of a native Latin masculine noun ending in -a.
You are right that occupational words that were typically associated with men tend to be masculine. Generally, nouns that describe people do match the gender of the person, though there are some exceptions.
Note: you’ll also find some -o nouns in Italian and Spanish that are feminine (e.g. la mano “the hand”).
Weeeellll... Latin doesn't distinguish nounal case endings from adjectival case endings. (I believe Russian does, which makes resolving certain grammatical questions much easier.)
But the gender of a noun is defined by the gender of an adjective that agrees with the noun. So quercus alta, a tall oak tree, is unambiguously feminine, despite ending in -us, because we can see that the adjective agreeing with it is feminine.
How do we know the adjective is feminine? That's easy, it ends in -a, and -a means feminine.
This tends not to support the theory that "-a does not mean feminine". :-/
In Latin, those nouns are grammatically feminine and would be referred to with feminine pronouns and modified with feminine adjectives. There are a handful of first-declension names that take masculine pronouns and adjectives, none of which spring to mind at the moment.
This is not correct; dnautics mentioned a set of nouns which are common and always masculine. Textbooks generally cover this set specifically. Wheelock provides a list and the acronymic mnemonic UNUS NAUTA, which -- it points out -- doubles as a way to emphasize that nauta is masculine, not feminine.
"abl. sing. only pinu; gen. and abl. plur. pinorum and pinis)", but then it goes on to cite the accusative plural pinos in Virgil. And that note implies a strict distinction between dative plural pinibus and ablative pinis, which seems weird. Not that the rest of it isn't weird, I guess.
(As an aside, the note for quercus that "dat. and abl. plural do not occur"... I can believe that a lack of genitive and dative forms for vis is a fact about the language. Dative and ablative plural forms existing for pine trees, but not oak trees, feels more like a coincidence of the historical record than a fact about the language.)
No, I'm not sure. See the sibling subthread. They're not less weird in the fourth declension, which is itself overwhelmingly masculine or neuter.
That said, second declension forms do seem to be attested for nearly every case of pinus.