Hi Eduardo,
Well there is no doubt that Acanthina lugubris and Acanthina angelica are two
different forms.  A. angelica has a tall spire, rather fine sculpture, and a
white interior.  A. lugubris has a low spire, heavy tubercles on the body
whorl, and a brown interior.  They also have different geographic ranges.  A.
lugubris is found on the west (outer) coast of Baja California, and up into
southern California, U.S.A.  A. angelica lives on the east coast of Baja, in
the Gulf of California.  So your specimens from San Felipe, way up at the
north end of the Gulf, would have to be A. angelica.  So, the only real
question is whether one of the two is a subspecies of the other.  I have never
seen them described as such.  The Oldroyd name you mentioned indicates that he
thought so.  However, Keen separates them as A. angelica Oldroyd, 1918 and A.
lugubris (Sowerby, 1822).
Regards,
Paul M.
Rhode island, U.S.A.