Lobed bats, butterfly bats, particoloured bats, thick-thumbed bats, Dormer's bats, bats, bats, BATS... did I mention the bats? (vesper bats part XVII)

Here we are, so close to the very end. I am pleased and surprised to find that we're now looking at the vesper bats within Vespertilionini - the clade that (in the topology I'm using here: that of Roehrs et al. (2010)) includes the pipistrelles and noctules and their closest relatives. We'll get to those extremely familiar bats soon. As usual, they have a bunch of far less familiar close relatives... or alleged close relatives, or possible close relatives... and it's those bats that we'll be looking at here. After, that is, that we deal with lobed bats and butterfly bats. They aren't members of Vespertilionini: as we'll see, they might be hypsugines or serotines.

Australasian lobed bats and African butterfly bats: probably not close relatives after all

Australia, New Guinea, New Caledonia and New Zealand are inhabited by the seven species of pied bats, lobe-lipped bats, groove-lipped bats or wattled bats (Chalinolobus) [the composite illustration above shows Gould's wattled bat C. gouldii on the left (by Neville W. Cayley, from wikipedia). The skull on the right belongs to an Asian particoloured bat Vespertilio sinensis (from HorácÄk (1997))]. Both a population of lobed bats from New Caledonia - regarded by some authors as the distinct species C. neocaledonicus - and the Long-tailed wattled bat C. tuberculatus from New Zealand are critically endangered. All of the lobe-lipped bats have dark brown or even blackish, fine, velvety fur, though a fringe of white hairs in C. picatus has led to the common name Pied wattled bat for this species.

As suggested by some of the common names (and the generic name: it means 'lobe mouthed'), small fleshy lobes (termed lip-lobules) project outwards from near the corners of the mouth, though these are quite small in some species (Chruszcz & Barclay 2002). The antitragus descends down the side of the face, extends beneath the eye, and terminates in another lobe close to the lip-lobule. The function of these facial lobes (if they have one) seems not to be known. Glands are present on the surface of the short, relatively wide snout. The diagram below - from Parnaby (1992) - shows the range of lip-lobules, tragi and antitragi present in lobed bat species.

The Chalinolobus species have sometimes been regarded as congeneric with the African butterfly bats or silvered bats (the nine species grouped together in Glauconycteris). Butterfly bats get their common name for their superficially moth- or butterfly-like flight style, made particularly noticeable by the fact that they often fly well before sunset. Their wings are often marked with patches of cream, brown and black, and their wing membranes have a particularly prominent venation: it's been suggested that these features might help the bats look like dead leaves and hence act as camouflage. The adjacent illustration (by Fiona Reid, from Gary Graham's 2002 Bats of the World) shows a Variegated butterfly bat G. variegata in flight and a Superb butterfly bat G. superba below it.

Chalinolobus and Glauconycteris are highly similar (butterfly bats even have those lip-lobules), and (apparently) only differ in minor features like the proportions of the metacarpals, the position of the outer incisor relative to the canine and the other incisors, and the relative size of the third upper molar (Koopman 1971). This strong similarity means that some authors have regarded them as congeneric: when this has been done, Chalinolobus gets priority since it was named in 1866 (Glauconycteris was named in 1875). Somewhat surprisingly, molecular data does not support close affinity of the two: Roehrs et al. (2010) found Chalinolobus to be part of their hypsugine group while Glauconycteris belonged in the serotine clade. Australasian lobed bats and African butterfly bats are thus not close at all if these results are correct - they're substantially separated, and their strong similarity must be the result of convergent evolution. Shockingly detailed convergent evolution, actually.

Vespertilio: the particoloured bats

Three short-eared, short-snouted Eurasian bats that possess concave regions on either side of the face are united in Vespertilio [adjacent photo of V. murinus by Mnolf, from wikipedia]. They're known as the frosted or particoloured bats due to silver-tipped hairs in the otherwise brownish pelage. A unique cartilaginous 'pseudobaculum' is present in addition to the baculum proper and makes the whole element long and slender, and thus superficially like the baculi of pipistrelles and noctules (Heller & Volleth 1984, HorácÄk 1997). Particoloured bats have long, slender wings and have a fast, direct style of flight. They will eat beetles and moths but mostly seem to prefer flies, aphids and other small insects (Rydell & Baagøe 1994).

Vespertilio murinus was the very first scientific name ever created for a bat. Linnaeus's very vague description of this species meant that later authors ended up applying the name to a whole list of European bats now known to be quite distinct from V. murinus as we understand it today, and an extraordinary amount of complexity was involved in sorting out the ensuing mess. As Wallin (1969) said "The road to the present nomenclature ran through an unparalleled chaos in vertebrate systematics" (p. 300). In truth, Linnaeus didn't definitely associate the name Vespertilio murinus with the Particoloured bat anyway: it has been argued that the bat he had in mind was more likely Myotis myotis (see discussion in Rydell & Baagøe (1994)). Even in recent decades, there are Vespertilio specimens and species that have been confused with serotines and noctules (see HorácÄk 1997).

Particoloured bat have typically been classified close to serotines, but some molecular data indicates instead that they form a clade with pipistrelles and noctules (Roehrs et al. 2010). However, Agnarsson et al. (2011) found particoloured bats to be most closely related to 'hypsugines' like Neoromicia and Hypsugo. Obviously, the name Vespertilionini has to go with whatever clade includes the particoloured bats. In accordance with the trees generated by Roehrs et al. (2010), I'm here using this name for the clade that also includes pipistrelles and noctules.

Until recently, fossil representatives of Vespertilio were only known from the Pleistocene and Holocene. A lower jaw from Russia has now extended their fossil record back to the Late Miocene (Rossina et al. 2006) [that jaw - identified as Vespertilio cf. villanyiensis - is shown here (the diagrams labelled a-c), with a lower jaw of V. murinus shown below. Both from Rossina et al. (2006). Scale bars = 3 mm].

Thick-thumbed bats and Dormer's bat

Two little known, superficially pipistrelle-like vesper bats with weird thickened pads on their thumbs and feet are united in Glischropus and sometimes known as the thick-thumbed bats (G. tylopus and G. javanus). Their affinities are uncertain and few phylogenetic studies have incorporated them, but in some recent classifications and phylogenies (Volleth & Heller 1984) they've been listed close to true pipistrelles and noctules.

A controversial species originally described as G. rosseti was argued to actually be a species of Myotis by Hill & Topál (1973) [the Myotis bats - the mouse-eared and little brown bats - were covered here]. Today it's sometimes called the Thick-thumbed myotis. The fact that vesper bats as phylogenetically distant as pipistrelle-like forms and mouse-eared bats might be confused with other another seems odd and surprising today, but prior to the 1970s it was fairly usual for bat experts to think that such taxa as Myotis, Pipistrellus (sensu lato) and Eptesicus were close relatives, and morphologically similar but for differences in premolar configuration.

Thick-thumbed bats are very small (head and body length is about 40 mm, weight is between 3.5 and 4.5 g) and they look as if they have particularly small eyes. The ears are long, reaching the tip of the snout. The upper surface of the snout slopes downwards, giving them a vaguely shrew-like profile. Thick-thumbed bats inhabit south-east Asia, Indonesia, the Philippines, Java, Sumatra and the Moluccas, and are often associated with bamboo, rock crevices and banana leaves. Like other bats with modified pads on the thumb and/or feet [adjacent diagram shows foot and thumb of G. tylopus], it seems likely that these features have evolved under selection pressure for an increased grip on smooth roosting surfaces. The pads in thick-thumbed bats are mobile (thanks to four sets of associated muscles) but they don't have an adhesive function: Thewissen & Etnier (1995, p. 933) concluded that the pads most likely are "involved in mechanical adhesion. It is possible that they interlock with the substrate or, more likely, they may act as a friction pad or wedge".

In the previous article we looked at both the bamboo bats or club-footed bat (Tylonycteris) - notable for their flattened skulls and flattened pads on their thumbs and feet - and at Eudiscopus denticulus, another flat-skulled little vesper bat that possesses 'gripping pads' (this time just on its feet). There's no clear indication that Tylonycteris, Eudiscopus denticulus or Glischropus are closely related (though affinities between some or all of them have been suggested), so it seems that these 'gripping' adaptations evolved independently on three separate occasions (actually more since the hypsugine Neoromicia nanus - popularly known as the Banana bat and until recently classified as Pipistrellus nanus (P. africanus is a synonym) - also has small pads on the wrist).

Dormer's bat Scotozous dormeri [shown here] is from India and Pakistan and has silver-tipped hairs scattered throughout its dark brown dorsal pelage. It has a reduced upper incisor dentition compared to pipistrelles, with the outer pair of incisors being either relictual or absent. You might remember from the nycticein article that the possession of a single pair of upper incisors was formerly regarded as a nycticein character. However, based mostly on its superficial resemblance to pipistrelles, authors have generally put it close to the pipistrelle assemblage (though remember that the large assemblage of vesper bats traditionally grouped together as pipistrelles or pipistrelle relatives are now known to be non-monophyletic). So far as I can tell, modern phylogenetic studies haven't incorporated it, and it remains little studied and poorly known.

And... we're not done yet. More soon. For previous Tet Zoo articles in the vesper bats series, see...

• Introducing the second largest mammalian 'family': vesper bats, or vespertilionids
• The vesper bat family tree: of myotines, plecotins, antrozoins, and all those cryptic species (vesper bats part II)
• Bent-winged bats: wide ranges, very weird wings (vesper bats part III)
• Of southern African wing-gland bats, woolly bats, and the ones with tubular nostrils (vesper bats part IV)
• The many, many mouse-eared bats, aka little brown bats, aka Myotis bats (vesper bats part V)
• Long-eared bats proper: Plecotus and other plecotins (vesper bats part VI)
• Desert long-eared bats - snarling winged gremlins that take scorpion stings to the face and just don't care (vesper bats part VII)
• Hairy-tailed bats: a tale of furry tails, red coats, cold tolerance, migration and sleeping out in the open (vesper bats part VIII)
• Robust jaws and a (sometimes) 'greenish' pelt: house bats (vesper bats part IX)
• Australasian big-eared bats, and how to (perhaps) single-handedly wipe out an entire species, 1890s-style (vesper bats part X)
• Antrozoins: pallid bats, Van Gelder's bat, Rhogeessa... Baeodon!! (vesper bats part XI)
• Putting the 'perimyotines' well away from pips proper (vesper bats part XII)
• Nycticein bats: apparently, a nice example of how assorted distant relatives can be mistakenly considered close allies on the basis of one or two characters (vesper bats part XIII)
• Eptesicini: the serotines and their relatives (vesper bats part XIV)
• Hypsugines: an assemblage of 'pipistrelle-like non-pipistrelles' (vesper bats part XV)
• A list of enigmas: bamboo bats, frogs-head flyers, Rohu's bat and the false serotines (vesper bats part XVI)

And for previous Tet Zoo articles on bats, see...

• Desmodontines: the amazing vampire bats
• Giant extinct vampire bats: bane of the Pleistocene megafauna
• Camazotz and the age of vampires
• Dark origins: the mysterious evolution of blood-feeding in bats
• A new hypothesis on the evolution of blood-feeding: food source duality involving nectarivory. Catchy, no?
• Oh no, not another giant predatory flightless bat from the future
• The most terrestrial of bats
• I stroked a pipistrelle
• Red bats
• We flightless primates
• Big animalivorous microbats
• Hidden in plain sight: discovering cryptic vesper bats in the European biota
• PROTOBATS: visualising the earliest stages of bat evolution

Refs - -

Agnarsson, I., Zambrana-Torrelio, C. M., Flores-Saldana, N. P. & May-Collado, L. J. 2011. A time-calibrated species-level phylogeny of bats (Chiroptera, Mammalia). PLoS Currents 011 February 4; 3: RRN1212. doi: 10.1371/currents.RRN1212.

Chruszcz, B. & Barclay, R. M. R. 2002. Chalinolobus gouldii. Mammalian Species 690, 1-4.

Heller, K. G. & Volleth, M. 1984. Taxonomic position of "Pipistrellus societatis" Hill, 1972 and the karyological characteristics of the genus Eptesicus (Chiroptera: Vespertilionidae). Zietschrift für zoologische Systematik und Evolutionsforshung 22, 65-77.

Hill, J. E. & Topál, G. 1973. The affinities of Pipistrellus ridleyi Thomas, 1898 and Glischropus rosseti Oey, 1951 (Chiroptera: Vespertilionidae). Bulletin of the British Museum (Natural History), Zoology Series 24, 447-454.

HorácÄk, I. 1997. Status of Vesperus sinensis Peters, 1880 and remarks on the genus Vespertilio. Vespertilio 2, 59-72.

Koopman, K. F. (1971). Taxonomic notes on Chalinolobus and Glauconycteris (Chiroptera, Vespertilionidae) American Museum Novitates, 2451, 1-10

Parnaby, H. 1992. An interim guide to identification of insectivorous bats of south-eastern Australia. Technical Reports of the Australian Museum 8, 1-33.

Roehrs, Z. P., Lack, J. B. & Van Den Bussche, R. A. 2010. Tribal phylogenetic relationships within Vespertilioninae (Chiroptera: Vespertilionidae) based on mitochondrial and nuclear sequence data. Journal of Mammalogy 91, 1073-1092.

Rossina, V. V., Kruskop, S. V., Tesakov, A. S. & Titov, V. V. 2006. The first record of Late Miocene bat from European Russia. Acta Zoologica Cracoviensia 49A (1-2), 125-133.

Rydell, J. & Baagøe, H. J. 1994. Vespertilio murinus. Mammalian Species 467, 1-6.

Thewissen, J. G. M. & Etnier, S. A. 1995. Adhesive devices on the thumb of vespertilionid bats (Chiroptera). Journal of Mammalogy 76, 925-936.

Wallin, L. 1969. The Japanese bat fauna. Zoologiska Bidrag från Uppsala 37, 223-440.