14.6 million year old fossil bee found in New Zealand

Paleontologists have described a previously unknown species of bee based on a fossil specimen found in southern New Zealand. It has been named Leioproctus barrydonovani.

The discovery was reported in the journal Zoosystema, and was briefly described by Sci News. The ancient insect belongs to the genus Leioproctus. It lived in the Middle Miocene, about 14.6 million years ago.

The only specimen was found in the middle Miocene deposits of Hindon Maar in Otago, southern New Zealand. The total body length of the fossil bee was 6.4 millimetres. Today, there are also bees of the Leioproctus species – small, black, hairy bees from 4 to 16 millimetres long.

"The single specimen is a compressed, articulated fossil bee preserved as a part and analogue in dark gray organic mudstone," the paleontologists write.

Modern bees of the Leioproctus species are found in Australia and South America, and are the most common species in New Zealand. But the discovery raises a number of questions.

"If the genus entered New Zealand earlier than 14.6 million years ago, the group should have had ample time to diversify significantly or develop floristic specialisation in the endemic flora," the researchers said. "However, in reality there are only 18 endemic species of Leioproctus."

They suggest that either there was diversification that was subsequently significantly reduced by extinction and unknown factors, or that some complex biotic processes or interactions prevented a line of more extensive speciation.

There is a third option – modern bees of the Leioproctus species, living in New Zealand, may not be related to fossil bees, at least in a subgeneric sense.

"In fact, there is currently no evidence to suggest that the three groups of Leioproctus in New Zealand form a monophyletic group, and they may themselves represent multiple, younger invasions of the islands," the authors of the paper note. "If the fossil record is evidence of an early invasion of Leioproctus into New Zealand during or before the middle Miocene, then it would suggest that more species could have evolved in the complex landscape and climate of the islands."

Paleontologists believe that bees of the Leioproctus barrydonovani species inhabited broadleaf forests and may have fed on the nectar of flowers of the genus Pseudopanax, which are still common throughout New Zealand today.