Mexican murex - what makes Kilayim Kilayim?
אֶת־חֻקֹּתַי֘ תִּשְׁמֹ֒רוּ֒ בְּהֶמְתְּךָ֙ לֹֽא־תַרְבִּ֣יעַ כִּלְאַ֔יִם שָֽׂדְךָ֖ לֹֽא־תִזְרַ֣ע כִּלְאָ֑יִם וּבֶ֤גֶד כִּלְאַ֨יִם֙ שַֽׁעַטְנֵ֔ז לֹ֥א יַֽעֲלֶ֖ה עָלֶֽיךָ
There are 3 types of Kilayim – Crossbreeding animal species, crossbreeding plant species, weaving wool and linen together.
The question is “what is a species” according to the Torah. Since there are a number of places that the definition of species plays a role, one can also wonder if the discussion in one area is pertinent to another. (For a very, very interesting and current discussion, look in our library and search for “sheep”. Start with Rav Aviner’s recent attack on Tekhelet from this quarter.)
So would another species (as defined by Linnaeus) of Murex like the Plicopurpura pansa be OK for Tekhelet? That is the question.
(Another question even if the answer to the above is positive, is this: Since the Gemara is sure that you have to kill the snail to obtain the dye, could that be a necessary factor? I.e., only Murex that need to be killed in order to obtain the dye would be kosher as a chillazon.)