|T. rex illustration by Matt Martyniuk, licensed.|
This idea at first seems very counter-intuitive. Abbreviating the genus name is common practice in biology and has been for a very long time. Some of these abbreviated binomials have even made it into common parlance, T. rex being the prime example, but also E. coli. However, just when this particular bit of dinosaurian shorthand moved from technical abbreviation to de-facto vernacular name for the species is an interesting question I'm probably too young to have a decent handle on. What follows is a little bit of cursory research I've done to try and answer the question, but anybody with a better living memory of the early 1980s should feel free to chime in with a comment that completely invalidates the rest of this post!
As a youngster in the '80s, I don't recall the term T. rex being very much on my radar. I have vague memories of associating the abbreviation as another quirky Bob Bakker-ism, but this may very well have only been after the influence of JP (Bakker was quick to adopt the JP-ism "raptor" as well, in the early '90s). As a young child, the towering 20ft-tall (in mostly incorrect erect pose) monster I saw in the American Museum of Natural History went mainly by his ominous full first name... Tyrannosaurus. A quick search through a few of my 1980s era books, both geared towards adults and kids, confirms this. A few of them never even use the species name rex. Apparently, even Bakker never once used the term T. rex in his seminal book The Dinosaur Heresies, which I'd have initially put money on as the popular source. Greg Paul uses it in Predatory Dinosaurs of the World, but this is a more technical book dealing with nomenclature and classification, where one would expect to find technical binomial abbreviations.
I decided to bring a little science to the effort and plug these various terms into Google's awesome Ngram tool, which creates graphs of word usage over time by searching the Google Books archive. I set the date range to between 1905 (the year T. rex was named) and 2008 (the last year Ngrams covers), and set the smoothing to 0 in order to get the graph as specific as possible with no averaging of the graph. I searched three terms at once: "Tyrannosaurus", "Tyrannosaurus rex", and "T. rex". Here is the result. Note that the results aren't perfect--after random spot-shcecking in Google Books, I found a use of T. rex from 1998 showing up with the date 1946, and Books itself (not sure about Ngrams) returns partial contractions, like "I don't Rex."
As one would expect, "Tyrannosaurus" is and always has been used more often than either more specific name, in part because the results return it twice (it is present both on its own, and as part of the binomial "Tyrannosaurus rex"). With such a cool-sounding binomial, it's no surprise that the full name "Tyrannosaurus rex" has been in consistent use since 1905. But, the JP hypothesis looks to be confirmed by the graph for the term "T. rex", which is essentially a flat line until 1988, when the JP novel was published (edit:it was actually published in 1990), and doesn't really take off until the early '90s, coincident with the media and marketing ramp-up to the movie.
However, a closer look at the Google Books sources presents some interesting counter-evidence to the JP hypothesis. Searching Books with the range 1970-1990 (basically the Dinosaur Renaissance period, when I figure "T. rex" is likely to have been popularized) yields several prominent pre-JP uses of the term. Most interesting is the use of "T. Rex" (with a capital 'R', rather than the correct lowercase) in Stephen King's 1988 novel The Tommyknockers. This book came out around the same time as Jurassic Park and so is probably too early to have been influenced by it.
Adjusting for variations in punctuation, I plugged a few different version of "T-Rex" into Ngrams. As I would have guessed, the notoriously incorrect version with a capital R and a hyphen seems to be mainly a post-JP phenomenon. "T. Rex" with a capital R and a full stop, however, had an early burst of popularity between the mid-1970s and early '80s.
And then it hit me. How could I forget? I guess I was blinded by science, because T. rex wasn't popularized by science or Jurassic Park at all. It was popularized by the band!
So we might be able to thank Marc Bolan, not Bob Bakker or Michael Crichton, for bringing this (accidentally?) scientific abbreviation into the popular lexicon.