Penis bones, echolocation calls, and genes betray new species of bats

If you’ve ever seen a bat fly at sunset, chances are it was a vesper bat. They are the largest bat family, consisting of 500 species, found on every continent except Antarctica. And most of them look a lot like that – they are small, with pale gray-brown fur, kind of like the bats of the bat world. This can make it difficult to tell the different types separately. But scientists have just discovered three new species and two new genera of vesperbats in Africa by comparing the genes of bats, their teeth and skulls, the high-frequency call they make at echolocation, and the small bones in them. penises.

“We did not know we had two new genera of bats until genetics told us, in no uncertain terms, that we had four very discrete groups and only two of them were named. It was then a matter of characterizing each of those groups. based on their other characteristics, ”says Bruce Patterson, the MacArthur Mammal Curator at Chicago’s Field Museum and senior author of the paper that introduces the new species and genera in the Zoological Journal of the Linnean Society. “Sure enough, their penis bones are so different from night and day.”

“We have discovered three new species of vesperbats in science, but perhaps more importantly, we have also solved the taxonomic relationships between the large number of species in this family, which resulted in the description of two new genera of African bats,” says Professor Ara Monadjem of the University of Eswatini and the lead author of the paper.

“After nearly a decade on this project, our sweat and efforts have been rewarded with the discovery of new species as reach expansions for others,” says co-author Paul Webala, a senior lecturer in natural biology at Kenyan Maasai Mara University. “Finding a new species is always exciting, but finding one that is hidden in plain sight is truly wonderfully inspiring and shows how fascinating the natural world is. The discovery deserves to be believed by biologists’ long-standing beliefs that only a small fraction of biodiversity is known as science. “

The bats in question live in Kenya and Uganda, and to study them, the researchers went to a delivery bus called “Batmobile” and went in search of bats.

“Bats are hard to find. They are small, some weigh less than 5 grams, they fly at night and hide during the day, but perhaps the most challenging part is that there are fewer than ever,” says Webala, “When we started the project ‘Bats of Kenya’ in 2011. it was a difficult but exciting exploratory journey into the known and the unknown. We searched through all the nooks and crannies, often camped and worked in the farthest parts. ran into the bat. caves, mines, volcanic tunnels like caves, sometimes crawling on our bellies. We were dirty and tired, but excited about our discovery in such perfect bat hides. “

They caught the bats in nets and examined them, taking measurements and tissue samples. They also recorded the bats’ conversations.

Many bats use echolocation to communicate, navigate and find their insect prey: they send out loud calls, and when the sound insects prey or their surroundings bounce, the bats triangulate their locations. The researchers built a portable flying cage and released the bats into it, recording the bats’ efforts to find a way out.

Back in the lab, scientists extracted DNA from the tissue samples, tracked them, and compared them with known bat genetic sequences in the GenBank database. Some of the sequences did not match and together they formed recognizably different groups.

Using the bats’ DNA suggesting new species and genera, the researchers examined the physical characteristics of the specimens they collect in the field. They found crucial differences in the heads and teeth of bats – and penis bones.

Penis bones, like bacula, are found in various groups of mammals – scientists remember them with the mnemonic PRICC (Primates, but not humans; Rodents; Insectivores, such as hedgehogs; Predators, such as dogs and seals; and Chiroptera, bats).

“The baculum is so variable. This is a bone that is not found in all mammalian species, and yet the variability is greater than any other bone in the vertebrate, in all vertebrates,” Patterson says. Because bacula comes in all shapes and sizes, even among closely related species, these different shapes can help keep animals from hybridizing with other species. “How that happens remains a mystery – especially when you think of the baculum as a key that fits a specific lock, it seems like many, many keys can fit an appropriate lock. Yet reproduction is a real complex interactions of neurology, physiology, and behavior and we do not understand the effects of all these variations in bacular structure. “

The bacula of the bats in this study are absurdly small, about 2 millimeters long. That’s hardly longer than a hyphen.

“They’re so small that you’re afraid you’ll lose them if you study them,” Patterson says. “We dressed them with a brilliant red-purple dye so that it was easier to find, and then stored them in separate small gelatin pill capsules.”

In addition to examining the bats ‘bodies, the researchers analyzed the bats’ calls that they recorded back in the “wedding dress.” Different species call at different frequencies to communicate with each other, Patterson explains: “Bats divide call frequencies for the same reason that radio stations divide the airwaves, to prevent them from interfering with each other.”

The researchers found that the calls of the bats, all higher than the highest beep a human can hear, distinguished them from other bats in the area. The final judgment was that there were three species new to science, and two new genera among the vesperbats they studied.

According to Patterson, the success of the research group was largely due to its international makeup: “I think the real secret ingredient to our success was that we had scientists who worked extensively in different parts of Africa and each a regional concept had the areas we studied. And by working together we had enough of the puzzle in hand that we could solve the rest of it. “Both Monadjem and Webala made in the course of this work multiple study trips to Chicago, organized by the Field Museum.

“I love working in African rainforests where the chances of an undescribed species are particularly high,” says Monadjem. “Our new taxonomic regulation of the species of rich vesperbats is based on a consensus of genetic and morphological characters that are likely to become the standard reference for this traditionally difficult-to-identify group.”

“The discovery of new species is important because it helps protect them and their ecosystems, especially from the direct role that humans play in their decline through environmental change, deforestation and agricultural intensification,” says Webala. “Each of these bat types, known and as yet unknown, is a marvel in itself, but may also hold the key to groundbreaking innovations in science as well as society.”

Patterson notes that the study has implications in the real world, because bats play an important role in human life, even if we do not realize it. “Vesper bats eat an extraordinary number of disease-spreading insects and crop-destroying bugs,” Patterson says. “Studying these bats is important – there is no way to document their roles in nature if we can not even tell them separately.”