Author: David J. Kahn
Theme: is spelled out at 39a: Antelope with spiraled horns (and a hint to this puzzle's theme) (ADDAX). In other words, the letters A and X are added to common phrases to create new and unexpected answers that are then clued. Like most themes it's easier to show than to spell out:
3d: Person born in northwest Germany 1,500 years ago? (NATIVESAXON).
6d: Deception requiring a vote recount? (TALLYHOAX).
25d: Is a student in a housekeeping course? (TAKESWAXING). Also, I guess, a class one might take in cosmetology
36d: Dissertation about neuron appendages? (AXONPAPER). My least favorite of the themed entries -- because I'm not too hip on sub-atomic stuff and I can't find a picture of an axon.
52a: Place for steamers? (SPA). Love those sauna jokes.
26d: NPR's Hansen (LIANE). Co-host with Will Shortz of the NPR Weekend Edition Sunday Puzzle, which I will win someday.
9d: Start of a noted palindrome (MADAM). As in "Madam, I'm Adam." My first thought was AMANA, as in the start to another noted palindrome "A man, a plan, a canal, Panama."
Suns of Bitches: Nothing really, although I did not and still don't know anything about "Knuffle Bunny" so 47d: Girl in the "Knuffle Bunny" books (TRIXIE) was tough.
Sundries: (Presented sans commentary due to poor time management)
27d: Gives out (EMITS).
Today's puzzle was brought to you by your friendly neighborhood addax.
Have a nice Thursday, Norrin