A Field Key to Bats of Lamanai, Belize Elizabeth L. Clare & Nancy B. Simmons © 2019
This key is an attempt to make identification as simple as possible.
It is based on external characters and should tell you when you cannot go further at
the net. If you catch anything that you cannot identify, PLEASE BRING IT BACK
for identification.
Abbreviations: F.A. = forearm length measured from top of wrist to end of elbow with wing folded.
Vampires
Desmodus is the vampire. It will hiss and scream when you touch it.
Vampires lack a tail membrane and have long, powerful hind legs with big feet. Their head can turn
most of the way around. Long forearms, huge thumb, two big chin pads, short nose leaf, and pointed
front teeth.
We suspect white-winged vampire bats Diaemus youngi may also be in the area.
Desmodus rotundus
F.A.=53-65
two chin pads pointed incisors
short nose leaf
huge thumb long forearms
Large Stripe-Faced Leaf-Nosed Bats (bigger than a chicken egg)
These bats have a pair of facial stripes on each side of their face, one above the eye and one below.
They do not have a stripe on their back and they lack tails.
If the facial stripes are bright it is either Artibeus lituratus or Artibeus intermedius. Forearm length
may be use to separate these species most of the time but some individuals may fall in the zone of
overlap in size. Upper surface of the tail membrane and legs are well-haired in both species.
If the facial stripes are faint and there is little hair on the upper surface of the tail membrane and legs,
it is probably A. jamaicensis. A. jamaicensis is often slightly smaller than the other two species.
Artibeus lituratus
F.A.=68-78
Artibeus intermedius
F.A.=61-69
Artibeus jamaicensis
F.A.=55-67
Small Stripe-Faced Leaf-Nosed Bats I (smaller than a chicken egg – no back stripe)
Dermanura and Vampyressa lack a stripe on the back. Dermanura species cannot be told apart
reliably at the net -- bring back to classroom. The vast majority of what we catch are Dermanura
phaeotis, D. watsonii may be present but we have not been able to confirm it.
Vampyressa is very small and fluffy but hard to differentiate from Dermanura without calipers and a
hand lens.
Dermanura and Vampyressa can be distinguished based on the front upper teeth. Dermanura has
small, bilobed upper incisors while the teeth in Vampyressa are larger and each comes to a single
point.
Dermanura phaeotis
F.A.=35-40
Dermanura watsoni
F.A.=35-41
Vampyressa thyone
F.A.=29-34
Vampyressa
Dermanura
Small Stripe-Faced Leaf-Nosed Bats II (smaller than a chicken egg – white back stripe)
Platyrrhinus and Uroderma can be easily distinguished from other stripe-faced bats by the bright
white stripe down the middle of the back
Platyrrhinus has a white fringe on the tail. Uroderma has no fringe.
Stripe image from wikipedia – please bring these back for photography.
Uroderma convexum
F.A.=40-44
Platyrrhinus helleri
F.A.=37-41 Stripe
Tail fringe
Platyrrhinus helleri
Small Plain-Faced Leaf-Nosed Bats I (smaller than a chicken egg)
Carollia can be distinguished from other small leaf nosed bats by their chins, which have a central
bump surrounded by many little ones arranged in a U. Carollia species are frequently mixed up with
Glossophaga… look for the dot. Both Carollia and Glossophaga have short tails in a broad tail
membrane.
Carollia perspicillata is slightly larger than C. sowelli. The only way to tell the Carollia species apart
reliably is by measuring the tibia. Colour is highly variable and thus not reliable.
Carollia perspicillata
F.A. = 41-45
Tibia = 21-23
Carollia sowellii
F.A. = 37-42
Tibia = 16-19 Large central bump +U
Small Plain-Faced Leaf-Nosed Bats II (smaller than a chicken egg)
Lampronycteris brachyotis normally has a bright yellow throat and V-shaped pair of chin pads. It has
a broad tail membrane and the calcar is as long as the foot.
Sturnira parvidens are yellow to orange all over. Sturnira lack a tail membrane and have very hairy
legs. Males have a sent gland on each shoulder that darkens the fur. They have a strong smell.
Glossophaga has a narrow snout and a chin with a central groove flanked by two chin pads with
serrated edges (no central bump like Carollia). They have a broad tail membrane but the calcar is
shorter than the foot.
Lampronycteris
brachyotis
F.A. = 40-42
Sturnira parvidens
F.A. = 37-42
Glossophaga soricina
F.A. = 33-38
Chin pads
Yell
Scent Gland
Yellow Fur Hairy Sturnira Legs
Large Big-Eared Leaf-Nosed Bats I
Lophostoma used to be Tonatia. One quick “Lophostoma test” is to touch its ears. Lophostoma will
probably fold them back against its head.
Mimon cozumelae has a large noseleaf and large ears that are distinctly pointed. Lophostoma evotis
has ears that are rounded and not pointed at the tip.
Note that there are other Lophostoma and Mimon at Lamanai see the previous and next page.
Trachops has a very bumpy chin and lips.
Lophostoma evotis
F.A.=47-54
Mimon cozumelae
F.A.=53-61
Trachops cirrhosus
F.A.=57-65 Bumpy chin
Large Big-Eared Leaf-Nosed Bats II
Gardnerycteris keenani (formerly Mimon crenulatum) has the longest nose leaf (2cm). The noseleaf
is hairy and has ridges or “crenulations” along the edges. The bat has a pale stripe down the middle of
its back.
Phyllostomus is hard to identify without practice. It has a pale chest, very rounded mouth a chin with
a row of warts along each side but none in the middle, and smallish pointed ears.
Gardnerycteris keenani
F.A.=46-55
Phyllostomus discolor
F.A.=60-68 Crenulations Dorsal Stripe
Small Big-Eared Leaf-Nosed Bats
Lophosotoma and Micronycteris are distinguished by differences in the chin. Lophostoma has a chin
with multiple small bumps, while Micronycteris has a v-shaped pair of large chin pads.
Lophostoma used to be Tonatia. One quick “Lophostoma test” is to touch its ears. Lophostoma will
probably fold them back against its head.
Micronycteris are extremely hard to identify. Micronyceris schmidtorum and M. microtis are
distinguished by the belly fur. In M. microtis it is brown and is the same color as the fur on the back.
In M. schmidtorum the belly fur is white or gray, much paler than the brown fur on the back.
Centurio senex – can’t miss it but hasn’t been seen in years.
Lophostoma brasiliense
F.A.=32-36
Micronycteris schmidtorum
F.A.=34-38
Micronycteris microtis
F.A.=32-37
Centurio senex
F.A.=41-45
Extremely Large Leaf-Nose Bats
Chrotopterus and Vampyrum are both huge bats with large, rounded ears and a nose leaf that forms a
cup underneath the nostrils.
Chrotopterus is the largest bat that we catch routinely. It is about the size of a fist and has woolly
gray fur.
Vampyrum has been captured at Lamanai. It is larger than Chrotopterus and has more silky fur that is
usually brownish. The face of Vampyrum often has dark splotches of pigmentation on the ”
Vampyrum spectrum
F.A.=101-110
Chrotopterus auritus
F.A.=77-83
Mormoopids – bats with frilly lips
These bats lack nose leafs but have complex lips and chins, short silky fur and slim bodies.
Mormoops has the most complicated lips and chin. Its eyes are especially tiny and its head is rounded.
Ears are rounded and funnel shaped.
Pteronotus species all have thickened lips and a single chin flap covered with small bumps. They all
have long pointed ears.
P.fulvus and P.personatus are both small. P.fulvus has wings that meet on its back making it look
“naked backed”.
Pteronotus mesoamericanus
F.A.=55-63
Pteronotus fulvus
F.A.=42-49 Mormoops megalophylla
F.A.=51-57
Pteronotus personatus
F.A.=42-49
Small Vespertilionids I
These are really hard to tell apart. It is very unlikely you can distinguish them at the net.
Front teeth can be used to tell Myotis from Rhogeesa. In Rhogeesa the canine is straight and needle-
like and followed by large premolars (so there is no obvious gap in the toothrow). In Myotis, behind
the canine there are two tiny premolars followed by a large last premolar, which makes it look like
there is a gap in the toothrow. Rhogeesa anaeus is smaller than the Myotis.
There may be two species of Rhogeesa at Lamanai. We are not sure.
We need to see tail fur to separate Myotis (we think – see next page). Fur colour is highly variable.
Myotis keaysi
F.A.=32-39 Myotis elegans
F.A.=32-39
Rhogeesa anaeus
F.A.=26-31
Myotis
Rhogeesa
Small Vespertilionids II
How to distinguish Myotis species:
We think you need to see whether the fur extends below the knee
We think you need to see if it forms a “V” shape.
We think this works….. but we aren’t sure how reliable it is.
Images reproduced from another key – please bring these back for photography.
Big Vespertilionids
Eptesicus is often confused with Myotis because it is only a bit bigger (they have slightly overlapping
FA measurements). At the net look for the gland on the upper lip. With a hand lens you might see that
Eptesicus lacks the reduced premolars seen in Myotis (no gap behind canine in Eptesicus).
Eptesicus and Bauerus both have swellings on their face that are actually a gland. The gland is much
larger in Bauerus. Bauerus is also a much larger bat.
Bauerus has long narrow ears and its nostrils are on the tip of the snout and open forward; in
Eptesicus the nostrils open more sideways.
Lasiurus has fur over most of the upper surface of the tail membrane; the others don't. Lasiurus is
yellow to yellow grey. Captures in recent years are very grey.
Bauerus dubiaquercus
F.A.=49-56
Lasiurus ega
F.A.=43-47
Eptesicus furinalis
F.A.=37-41
Noctilio – fishing bat
Very large bats with giant feet!
Very short orange fur, sometimes brown. Wings are partly transparent – you can read through them.
Ears curl back sometimes. Stripe down the back. Enormous calcar.
Males and females are hard to tell apart. Females have a “pseudo-penis” that points up. Males point
down. Females often have prominent nipples.
Male Noctilio leporinius
F.A.=82-89 Female
Sac-winged Bats I
Males of most species have a slit above the elbow that forms a sac. It is missing or rudimentary on
females.
All sac-wing bats have pointed noses. Their lips extend over their bottom lips. Their ears are small,
pointed backwards, and have prominent internal ridges. They are very delicate bats. Females are
slightly smaller than males but the genders are very hard to tell apart.
Saccopteryx and Rhynchonycteris have two stripes down the back. Rhynchonycteris has tufts of white
hair on its forearms and lacks sacs. Saccopteryx has black or very dark brown fur, while
Rhynchonyteris is distinctly frosted in appearance.
Saccopteryx bilineata
F.A.=44-48
Rhynchonycteris naso
F.A.=36-40
Tufts of fur
Saccopteryx bilineata R. naso
Two wavy lines
Sac
Sac-winged Bats II
Peropteryx is the delicate and is plain brown with no stripes and no frosting. Peropteryx has a “butch”
haircut with no fur on most of face but fur rises sharply on forehead.
Diclidurus has its sac in the tail membrane and bright white fur.
Diclidurus albus
F.A.=63-69
Peropteryx kappleri
F.A.=45-52
Molossidae – bats with free tails
Molossids all have “dog faces” with curled ears, flat bodies and much of the end of the tail sticks out
of the tail membrane in a skin sheath. It is unlikely that any can be identified at the net.
M. rufus and E. auripedulus are very hard to tell apart but Eumops has a broad flat snout while
Molossus has a narrow snout with a sharp crest down the middle. You can’t identify these without
calipers and a hand lens. Eumops nanus is very small.
M. alvarezi can be identified from the other two by blowing on the fur. The base of the fur is very
white.
We suspect that Molossus molossus (F.A.36-40) and a number of other species of Eumops are in the
area but we have not caught them in recent years.
Molossus alvarezi
F.A.=45-52
Molossus rufus
F.A.=47-54
Eumops auripendulus
F.A.=57-63
Eumops nanus
F.A.=37-49
Natalids – Funnel Eared Bats
Natalus has been captured only at Ka’Kabish. It is a small, delicate bat that lacks a nose leaf, and has
funnel-shaped ears that almost completely wrap around the tiny eye. The hind legs and tail are very
long, and it has a long tail membrane. The fur is orange."
Natalus mexicanus
F.A.=36-39
