High in the Himalayas in 2008, a tiny flash of yellow caught Paul Egan’s eye. The poppy intrigued the doctoral student in botany at Trinity College Dublin, as he was already attempting to study the ecology of several species of Himalayan poppy.

Egan extensively documented the bright yellow blooms that he found, tentatively concluding that this flower was a new species. However, he eventually figured out that other scientists had collected samples of the same flower starting in the 1960s but didn’t realize it was new. The samples sat on shelves for nearly 50 years, until Egan finally published the first formal description of Meconopsis autumnalis and the closely related M. manasluensis last year in the journal Phytotaxa.

Such a delay is not unusual, a study published Monday in Current Biology finds. On average, more than two decades pass between the first collection of samples of a new species and the publication of the species’ description in scientific literature. With species falling into extinction at record rates, many already-collected organisms may die out before they ever make it into scientific literature, researchers say.

To quantify the lag between discovery and publication, Benoit Fontaine, an ecologist at the National Museum of Natural History in Paris, surveyed with colleagues the 16,994 new species whose formal descriptions were published in 2007.

Of these, the researchers randomly picked 600 species to analyze more closely. The lag between the initial collection of a new species and its formal publication in the research literature averaged 21 years for those 600 species, they found. The median time between collection and publication was 12 years. Fontaine refers to this time gap as a species’ “shelf life.”

In previous centuries, newly collected species would routinely gather dust for decades before being written up. And the process doesn’t necessarily move any faster today.

Fontaine and colleagues also examined a variety of factors that might affect a species’ shelf life. Unexpectedly, the average shelf life of species discovered by amateur collectors was 15 years, compared with 21 years for professional biologists. Species also had a shorter shelf life when they were discovered by researchers living in countries whose average per capita income was less than $35,000 – perhaps because those researchers are already in the places where most new species are found.

New aquatic species also had a significantly shorter shelf life than new terrestrial species.

But several nonscientific factors likely increase a species’ shelf life, Fontaine says. The descriptions of new species aren’t seen as sexy, and many top journals don’t frequently publish papers that simply describe a new species. So, a young researcher looking to get tenure might opt to write a seemingly more sophisticated, hypothesis-driven paper published in a higher-tier journal and shelve largely descriptive findings from a field expedition to be published later.