Just because you were part of the ensemble cast of a movie that got a SAG nomination for Best Ensemble, that doesn't mean you got a nomination. Remember Saturday Night Live's Taran Killam in 12 Years a Slave? He and Scoot McNairy played ostensible performers who lured main character Solomon Northup into their clutches and sold him into slavery. They shared every scene together. This morning, when SAG honored 12 Years a Slave with a Best Ensemble nomination, McNairy was nominated and Killam was not.

Due to their rather arbitrary rules, SAG determines who is and isn't included in Best Ensemble recognition by virtue of how (and where) they're credited:

“The Cast of a Motion Picture” includes all actors whose names appear in the cast credits of the final release print. Motion Picture casts shall be represented by those actors billed on separate cards in the main titles, wherever those titles appear. In cases of special, unusual or non-billing or credit, eligibility shall be at the sole discretion of the Screen Actors Guild Awards Committee. Members of the cast who are not single billed but are credited in the cast crawl of the motion picture announced as the recipient of the Outstanding Performance by the Cast of a Theatrical Motion Picture shall each receive a certificate.

The Screen Actors Guild Awards are the highest-profile awards-giving organization to recognize the work of ensemble casts. This is a very good thing, and something other awards should emulate. It just gets frustrating when the parceling out of nominations doesn't seem to make a whole ton of sense. 

Here's a look at the Best Ensemble category, who was recognized with nominations, and who was left out.

12 Years a Slave

Nominated: Benedict Cumberbatch, Paul Dano, Garret Dillahunt, Chiwetel Ejiofor, Michael Fassbender, Paul Giamatti, Scoot McNairy, Lupita Nyong'o, Adepero Oduye, Sarah Paulson, Brad Pitt, Michael Kenneth Williams, Alfre Woodard.

Not Nominated: Taran Killam, Kelsey Scott (as Solomon Northup's wife), Quvenzhane Wallis (who is only a cameo, so that's actually fine), former Mad Men star Bryan Batt.

American Hustle

Nominated: Amy Adams, Christian Bale, Louis CK, Bradley Cooper, Paul Herman, Jack Huston, Jennifer Lawrence, Alessandro Nivola, Michael Peña, Jeremy Renner, Elisabeth Rohm, Shea Whigham.

Not Nominated: Robert DeNiro, whose cameo is uncredited. Colleen Camp, who played Brenda the cat lady and essential part of the ABSCAM stings.

August: Osage County

Nominated: Abigail Breslin, Chris Cooper, Benedict Cumberbatch, Juliette Lewis, Margo Martindale, Ewan McGregor, Dermot Mulroney, Julianne Nicholson, Julia Roberts, Sam Shepard, Meryl Streep, Misty Upham.

Not nominated: No, that's pretty much everyone.

Dallas Buyers Club

Nominated:  Jennifer Garner, Matthew McConaughey, Jared Leto, Denis O'Hare, Dallas Roberts, Steve Zahn.

Not nominated: Kevin Rankin, who plays Ron Woodrooff's fair-weather rodeo friend. Griffin Dunne, who has a fairly significant role as a doctor working off the grid in Mexico.

Lee Daniels' The Butler

Nominated: Mariah Carey, John Cusack, Jane Fonda, Cuba Gooding Jr., Terrence Howard, Lenny Kravitz, James Marsden, David Oyelowo, Alex Pettyfer, Vanessa Redgrave, Alan Rickman, Liev Schieber, Forest Whitaker, Robin Williams, Oprah Winfrey.

Not nominated: True Blood's Nelsan Ellis, who played Martin Luther King, Jr. Yaya Alafia, who played Oyelowo's "trifling, low-class bitch" (per Oprah's character) of a girlfriend. Minka Kelly, who played Jacqueline Kennedy, despite a nod for Marsden as JFK. Elijah Kelley, who played Cecil Gaines' other, much gayer(-seeming) son.