Tag Archives: taxonomy

Bats come in all shapes and sizes

Bats are mammals belonging to the order Chiroptera, a name of Greek origin meaning “hand-wing,” which accurately describes the animal’s most unusual anatomical feature. Their forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels and gliding possums, can only glide for short distances. Unlike birds, bats do not flap their entire forelimbs, but instead flap their spread-out digits, which are very long and covered with a thin membrane.

Did you know that humans, birds, and bats have the exact same types of bones in their forearm? The bones look different as they have been modified to have different functions.
Did you know that humans, birds, and bats have the exact same types of bones in their forearm? The bones look different as they have been modified to have different functions.

Within Chiroptera two distinct groups or sub-orders are found. The first are the small, insect eating bats called Microchiroptera (micro-bats). Bats within this group include those that roost in caves or in tree cavities and are found worldwide. The second is Megachiroptera (mega-bats), a group that includes all the large bats, including flying-foxes, which predominately eat fruit and nectar. This group is mainly confined to south-east Asia and the Pacific, including India and Australia. One of the largest bats in the world, the Giant golden-crowned flying-fox, Acerodon jubatus, comes from this region,  calling the forests of the Philippines home. 

Giant golden-crowned flying fox has a wingspan of 1.7m (5 ft 7 in)
Giant golden-crowned flying fox has a wingspan of 1.7m (5 ft 7 in)

Even though the names imply otherwise, not all Megabats are larger than Microbats. While certain species of flying-foxes can have wingspans of up to 152cm (5 feet), other flower-feeding members such as the blossom bats, which include the Common blossom bat, have wingspans as small as 7.2cm (2.8 inches).

Some species of Microchiroptera however are very tiny like their name implies. The smallest of this group is probably the Philippine bamboo bat, Tylonycteris pachypus.  This bat is about the size of a bumble bee and is among the smallest mammals on earth, measuring about 40 millimetres (1.6 in) in length and weighing only 1.4 grams (0.05 ounce). Being so small enables them to roost in small groups in the internodes of bamboo.

Lesser Bamboo Bat (Tylonycteris pachypus) emerging from daytime bamboo hideout
Lesser Bamboo Bat (Tylonycteris pachypus) emerging from daytime bamboo hideout

The largest microbat is the tropical American false vampire, Vampyrum spectrum, with a wingspan of up to 1m  (40 inches). It is carnivorous, eating birds and small mammals. This species occurs throughout Veracruz (Mexico) to Ecuador and Peru, Bolivia, north and southwest Brazil, and Guianas; It is also found on Trinidad. 

Feature image courtesy of Andrea Janda

What is it like to find a new bat species?

One of the greatest privileges of working at the Smithsonian is that you get to be on hand when exciting discoveries happen, like finding a new bat species!

My friend and fellow bat specialist Ricardo Moratelli has been working on finding new bat species for over 10 years! His focus is on the Myotis genus, one of the most difficult Neotropical genera of bats to understand. So far he as found 6 new species to science, including the recent golden bat species, Myotis midastactus.  

In an article for Smithsonian Science, I ask Ricardo what it is like to be a bat detective finding new species!! 

Bolivia’s golden bat: one of six new species found by the Smithsonian’s bat detective

Ricardo Moratelli, a scientist at the Oswaldo Cruz Foundation (Brazil) and post-doctoral fellow at Smithsonian’s National Museum of Natural History.
Ricardo Moratelli, a scientist at the Oswaldo Cruz Foundation (Brazil) and post-doctoral fellow at Smithsonian’s National Museum of Natural History.

 

The Eastern tube-nosed bat

Tube-nosed bats are some of the strangest looking bats you might find, but in a weird way they are also some of the most endearing!

Eastern Tube-Nosed Bat - Nyctimene robinsoni
Eastern Tube-Nosed Bat – Nyctimene robinsoni

The Queensland or Eastern tube-nosed bat, Nyctimene robinsoni, is a megabat in the family Pteropodidae that lives in northeastern Australia. As its name suggests, these bats have long tubular nostrils. Scientists are not really sure why these tubes evolved but they have several theories as to what purpose they serve.

Eastern tube-nosed bats eat mainly fruit and nectar from the rainforest canopy. Some scientists believe that their tube-like nostrils to help the bats breath, like a snorkel, when they are eating a juicy fruit! Other theories include roles in olfaction, acting like stereo nostrils, allowing the bat to home in on a piece fruit in the rainforest understory.

Tube-nosed bats that live in rainforest habitat often have a green tinge to their wings or fur, which helps keep them hidden in foliage during the day. Eastern tube-nosed bats are a rich brown colour, with a greyish head. Unlike other fruit bats, they prefer to roost alone in thick vegetation. Their sparse yellow to green spots on their wings and ears helps to camouflage them when they wrap themselves in their wings.

At night they fly rapidly and with great maneuverability just above or below the forest canopy, making a distinctive, high-pitched whistling call. Mating occurs from July to September and a single young is born after a gestation period of 3-3.5 months.

This species is moderately common in the northern part of their range in Queensland, but is listed as vulnerable New South Wales.

Eastern Tube-nosed Bat - Photo: Micheal Pennay
Eastern Tube-nosed Bat – Photo: Micheal Pennay

 

 

 

 

 

 

New Mormopterus species honors a true bat lady.

One of the biggest honors you can ever receive, as a biologist, is to have a species named after you. Just that happened last week to a dear friend and mentor of mine Dr. Lindy Lumsden, who had a species of free-tailed bat named after her.

New species, Mormopterus lumsdenae, named after Dr. Lindy Lumsden.
New species, Mormopterus lumsdenae, named after Dr. Lindy Lumsden.

The Northern Free-tailed Bat, now known as Mormopterus lumsdenae, is found in the northern regions of Australia across the states of Queensland, the Northern Territory and Western Australia. It is one of three new species for this genus having been recently described in a paper published in the Australian Journal of Zoology. This new research published by Reardon et al. is important not only because it honors my dear friend, but also because it finally sheds light on a taxonomic group whose uncertainty has been a longstanding impediment to research and conservation efforts.

Members of this genus have been notoriously hard to identify for a long time mainly because they all look incredibly similar in the field. Indeed for a long time several species of this genus could be distinguished only by the structure of the glans penis, which requires some very intimate examinations and large magnifying glasses. It was Lindy who showed me how to do this when she took me on my first ever field trip catching bats, something I am not likely to ever forget!

Species of the genus Mormopterus are some of my personal favorites, as these bats are not only some of the first I ever had the privilege to catch but they also have interesting little behaviors as well. For example, instead of desperately trying to get away like most microbats do when you trap them, often Mormopterus species like to play dead. It comes in very handy when you are trying to take measurements, as they are not always struggling to get away!

Dr. Lindy Lumsden, Wildlife Ecology team leader for the Arthur Rylah Institute for Environmental Research

I think it is very fitting that Lindy have a Mormopterus species named after her as Lindy is well known for having two little bats of this genus help her with the hundreds if not thousands of public talks she has done over the years. If you were to ask any of the participants what their favorite memory was from one of Lindy’s talks, no doubt they would mention George or Grump. These two little Mormopterus bats came to Lindy a long time ago and could not be released back into the wild. So instead, Lindy looked after them, believing that they may only live six months to a year as no one had ever kept these bats in captivity. Twenty plus years later Lindy was still taking them to public talks, showing children to pensioners how beautiful these little creatures truly are. George sadly passed away in 2012 but Grump, although retired from public life, is still going strong.

Lindy has always had a passion for bats, something that she has not only passed on to me but also the thousands of people she has come across in her many years of teaching students, giving public talks and advocating for the conservation of bats. I commend Terry Reardon and his colleagues for not only a truly important piece of taxonomic work that will help the conservation of these species, but also the wisdom for celebrating a dedicated scientist with the highest honor her colleagues could bestow.

Penis spines help scientists identify bat species

Sometimes you need to look in unusual places to tell species apart. Some mammal species are easily distinguished by differences in their fur or skeletons, while other more cryptic groups require further scrutiny in their more delicate areas.

Ph.D. student Ligiane Moras is doing just that in her attempt to find characteristics that can separate species in a group of dog-faced bats, Cynomops, native to Central and South America. Using the extensive bat collection at the Smithsonian’s National Museum of Natural History and a very powerful electron microscope, Moras has found potential species differences in the tissues, glans and spines that cover the skin of their tiny penises.

“Epithelial spines can be found on the penis of many bat species. The spines on these bats are microscopic, about 20 micrometers long, so you can only see them with the electron microscope” Moras says. “All the bats in this group have these spines, but I have been able to find differences between potential species in spine length.”

 

Genitals come in many different shapes and sizes

DSC01655

Extreme variation in male genital morphology is a common trend across animals that reproduce through internal fertilization, including bats. Even closely related species with similar general morphology often have strikingly different genitalia. “When I couldn’t find differing characteristics in the skeleton or skins of this bat group, I started looking at the structures of the penis,” Moras explains. “Often changes can be found in the genitals between species due to sexual selection.”

 

Sexual selection is a mode of natural selection in which some individuals out-reproduce others of a population, which eventually can lead to the formation of a new species. Successful individuals may have behavioral or morphological traits that better ensure their genes are passed on to the next generation. These may include traits that attract the opposite sex, enable the successful delivery of sperm or ensure the survival of their young.

 

Penis spines wage war in the sperm competition

bat_penis_spikes

While the purpose of the spines has not been fully uncovered, scientists believe they might assist in this sexual competition. In mammal species where females frequently mate with multiple males, competition between males extends beyond attraction of mates to include sperm competition. These spines might have several roles, such as acting like a microscopic brush to remove competing sperm from the female reproductive tract or, in some bat species, aiding in the removal of a sperm plug.

 

In some bat species the male deposits a gelatinous secretion into the female’s genital tract after his sperm is delivered. This secretion later hardens to create a barrier to the sperm of competing males. Breaking down this barrier and removing the rival sperm before they reach the egg is crucial if a newcomer is going to have a fighting chance at fatherhood.

 

Looking in other unusual places to organize the bat family tree

 

While Moras has had some success in finding several characteristics of the penis that differ between potential species of the Cynomops genus, it is not the only place she is looking.

 

“I have also used the electron microscope to look at the tongue structure of these specimens,” Moras says. “I have found that the number of fungiform papillae on the side of the tongue–the little bump-like structures we also have on our own tongues–vary in frequency between potential species of this genus”.

 

Moras, who is studying zoology at Universidade Federal de Minas Gerais inBelo Horizonte, Brazil, aims to publish her taxonomic work in the near future, when she will present a complete family tree for this bat genus based on the different morphological characteristics she has found in some unusual places.