Tetrapod Zoology

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About 12 species of big-eared Australasian bats are known as the, err, Australian big-eared bats and New Guinean bats. More formally, they are the Nyctophilus species. They’re also known from some of the islands that surround New Guinea (like the Lesser Sundas), and also from New Caledonia (an endemic New Caledonian species, N. nebulosus, was named in 2002). Their presence has also been claimed for Fiji, but the evidence for this (based on specimens stored at the Natural History Museum in London) is inconclusive (J. E. Hill, in Parnaby 2002). Together with the New Guinea big-eared bat or Thomas’s big-eared bat Pharotis imogene, these bats have often been given their own ‘subfamily’ (Nyctophilinae) or ‘tribe’ (Nyctophilini) (e.g., Tate 1942, Koopman & Jones 1970, McKenna & Bell 1997). I’ll be referring to both Nyctophilus and Pharotis as the nyctophilins. Yes, we’re now on part X of the vesper bat series: for the other parts, follow the links given below [adjacent photo shows a Mount Missim big-eared bat N. shirleyae, a species named as new in 2009].

The phylogenetic position of Nyctophilini is somewhat controversial, and I’ve put them in this part of the series simply because they’ve traditionally been positioned somewhere close to pallid bats and their relatives (Antrozoini) (the next vesper bat clade we’ll be looking at). However, Volleth & Tidemann (1991) suggested that they might be part of Vespertilionini, though note that this name was used for a clade that included various vesper bats regarded in the series here as hypsugines, vespertilionins and members of the serotine clade.

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As suggested by some of their common names, nyctophilins have particularly large ears. Like the huge ears of plecotins, these are usually joined at their bases by a web of skin across the forehead (this is not the case in the Small-eared nyctophilus N. microtis) [adjacent head illustration of N. gouldi from Parnaby (1992)]. Their ears are also prominently ribbed and very broad – about as broad across the base as they are long, actually. The snout in these bats is quite deep and grades gently into the braincase (recall that, in such vesper bats as woolly bats and myotines there is often a pronounced ‘step’ between the low snout and globular cranium). Their premolar dentition is reduced, with just one upper and two lowers (Tate 1941).

While vesper bats are generally said to lack nose leaves and other such structures, nyctophilins are the exceptions, since they possess small, horseshoe-shaped nose leaves around their nostrils. Behind the nose leaf, a bilobed convexity rises from the upper surface of the snout. It differs in shape and size among the species and (together with the width of the toothrow across the upper canines and penis anatomy) provides a reliable way of distinguishing some of the species. In N. geoffroyi, for example, the bump is tall and its two lobes are connected by an obvious membrane [see diagram below; from Parnaby (1992)], while in N. bifax the bump is low and the midline membrane is absent (Parnaby 1992).

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It was suggested by Tate (1941) that the species within the group could be classified into several species groups, distinguishable via the size of their auditory bullae, ears, snout width and other features. It seems obvious that there are relatively large species with robust snouts and proportionally large auditory bullae and also relatively small species with more gracile snouts and proportionally small auditory bullae. However, as usual there are species that form a range of intermediates and overlaps in the middle and Dobson (1878) even suggested that all the species should be synonymised. That view is certainly not tenable, but a modern phylogenetic evaluation of the group is definitely required: do big, broad-snouted, big-eared species really go together, or might some be more closely related to the small species? And what of all the species named since Tate (1941) was published? Some of the post-1941 species – like N. microdon from New Guinea (named in 1954) – are particularly distinctive. The group was recently reviewed by Parnaby (2009) who named two new species (N. shirleyae and N. corbeni) and suggested the presence of seven ‘species groups’, one of which housed N. microdon on its own.

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Nyctophilins seem to be ecologically flexible, adaptable bats, able to forage in woodland, scrubland and arid habitats, and they’ve even moved into urban areas. They have a slow, fluttering flight and are highly manoeuvrable, pursuing insects in the open air but also gleaning from vegetation and even the ground. Some Nyctophilus species are even able to take off from the ground with a single leap and downward flap of the wings; in this respect they’re somewhat like the Pallid bat (Antrozous pallidus) [adjacent photo of N. gouldi in flight by Terry Reardon; from here].

A Nyctophilus species described from a single fossil skull – N. howensis from Lord Howe Island – might have survived into recent times (or perhaps still be extant), since eyewitness accounts of a large bat on the island seem to match it (Nowak 1999). A supposedly distinctive Nyctophilus-like bat was described from Mount Lamington, Papua New Guinea, in 1968 and named Lamingtona lophorina. However, more recent appraisals have regarded it as a synonym of N. microtis (Hill & Koopman 1981). Other species remain very poorly known. N. heran from Lembata Island, Indonesia, is only known from a single specimen.

The sad, sad tale of Pharotis imogene

A really obscure and apparently very rare vesper bat from New Guinea – the New Guinea big-eared bat or Thomas’s big-eared bat Pharotis imogene – is an assumed close relative of the Nyctophilus species. Like those bats, Pharotis has both large ears and a horseshoe-shaped nose leaf (Nowak 1999). Its snout is shorter than that of the Nyctophilus bats and its ears are larger. Not much else is known of it, other than that it inhabits, or inhabited, lowland sclerophyll woodland in Central Province, southeastern Papua New Guinea. Below is what seems to be the only available photo: I borrowed it from here, but you might recognise it from Walker’s Mammals of the World (where it’s credited to “Howard Hughes through Australian Museum Sydney”).

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All 45 known specimens were collected in 1890: all are female, and there are suspicions that they represented a single maternity colony. If so, it’s plausible that the collector single-handedly wiped out the very last colony. I totally understand the necessity of collecting zoological specimens. We need to do it if we want to document the existence of populations without ambiguity. But I confess to being a little confused as to why someone would proceed to euthanise and take home every single individual from a small colony. Still, it was 1890 I suppose. A clue that all is not lost comes from a possible specimen, also from Central Province, collected in 1985. Unfortunately, this individual was destroyed (I don’t know why) in 1992 and never had its identity confirmed.

Nyctophilins remain somewhat enigmatic. Superficially a little like plecotins – and occasionally confused with them in the 1800s – they were later regarded as close to antrozoins, and more recently suggested to be close to the clade that includes serotines, hypsugines and vespertilionins. Behaviourally flexible and morphologically aberrant compared to other vesper bats, they also contain more than their fair share of mysterious species. There are those known from just a few, or even single, specimens, those of uncertain provenance, and those suspected of now being extinct. And if you want to know more, you’ll have to get into the primary literature, for it’s time for us to move on once more.

For previous Tet Zoo articles in the vesper bats series, see…

And for previous Tet Zoo articles on bats, see…

Refs – –

Dobson, G. E. 1878. Catalogue of the Chiroptera in the Collections of the British Museum. British Museum: London.

Hill, J. E. & Koopman, K. F. 1981. The status of Lamingtona lophorhina McKean and Calaby, 1968 (Chiroptera: Vespertilionidae). Bulletin of the British Museum (Natural History), Zoology Series 41, 275-278.

Koopman, K. F. & Jones, J. K., Jr. 1970. Classification of bats. In Slaughter, B. H. & Walton, D.W. (eds.) About Bats: a Chiropteran Biology Symposium, pp. 22-28. Southern Methodist University Press, Dallas.

McKenna, M. C. & Bell, S. K. 1997. Classification of Mammals: Above the Species Level. Columbia University Press (New York).

Nowak, R. M. 1999. Walker’s Mammals of the World, Sixth Edition. The Johns Hopkins University Press, Baltimore and London.

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

– . 2002. A new species of long-eared bat (Nyctophilus: Vespertilionidae) from New Caledonia. Australian Mammalogy 23, 115-124.

– . 2009. A taxonomic review of Australian greater long-eared bats previously known as Nyctophilus timoriensis (Chiroptera: Vespertilionidae) and some associated taxa. Australian Zoologist 35, 39-81.

Tate, G. H. H. 1941. Results of the Archbold Expeditions. No. 40. Notes on vespertilionid bats of the subfamilies Miniopterinae, Murininae, Kerivoulinae and Nyctophilinae. Bulletin of the American Museum of Natural History 78, 567-597.

– . 1942. Results of the Archbold expeditions. No. 47. Review of the vespetilionine bats, with special attention to genera and species in the Archbold collection. Bulletin of the American Museum of Natural History 80, 221-297.

Volleth, M., & Tidemann, C. R. (1991). The origin of the Australian Vespertilioninae bats, as indicated by chromosomal studies Zeitschrift für Säugetierkunde, 56, 321-330

Comments

  1. #1 DMA
    April 7, 2011

    Sad that they would wipe out an entire colony. Darren, when are you going to do your squamazoica project you promised in July. Sorry, I know your busy.

  2. #2 heteromeles
    April 7, 2011

    Pharotis imogene, Aproteles bulmerae–wiping out PNG colonies for collections. Sheesh! That’s so Victorian!

    Incidentally, are these are the X bats?

  3. #3 llewelly
    April 7, 2011

    Didn’t collectors play an important role in the extinction of the Great Auk many decades earlier?

  4. #4 Patrick
    April 8, 2011

    In herbarium collections, I occasionally come across plant specimens labelled: “Only one was seen.” And there it is, squished on the page.

    More baffling are a couple of botanists I know who go out to collect rare plants–at well-documented sites that they’ve visited before! There are occasionally good reasons for this (e.g., you need fresh material for DNA isolation), but most of the time it’s, I dunno, just a fixation on rarity or something.

  5. #5 Darren Naish
    April 8, 2011

    Thanks for comments. DMA: not yet sure when I’ll run the squamozoic stuff (there’s now quite a lot of it). Just looked at the illustrations again and there’s definitely enough material for a good article. April 1st 2012?

  6. #6 Dartian
    April 8, 2011

    Darren:

    The group was recently reviewed by Parnaby (2009) who named two new species (N. shirleyae and N. corbeni)

    I was curious about the former name, so I looked up Parnaby (2009). There he says that he named the new species after his mother, Shirley.

    Incidentally, in the same paper Parnaby also describes a new subspecies (I know, I know…) that he named Nyctophilus major tor; he says that tor is “a random combination of letters, selected for brevity” (p. 60).

  7. #7 Darren Naish
    April 8, 2011

    Funnily enough, I also found the etymology of these two taxa interesting – so much so that I considered mentioning it. I was reminded of the extinct raptor Pengana robertbolesi (popularly known these days as the flexiraptor), named by Robert Boles in honour of his dad. My dad isn’t called Darren, but if I had enough new taxa to spare I’m sure I’d name one after him (and my mum) :) Anyway… Parnaby’s (2009) paper is also neat in including great photos of N. howensis.

  8. #8 Dartian
    April 8, 2011

    Speaking of names…

    Central Province, southeastern Papua New Guinea

    Apologies for going off-topic, but does anyone know why the region in question is called the ‘Central’ Province? It is, after all, located very far to the east indeed on mainland New Guinea.

  9. #9 valagos
    April 8, 2011

    All right, I’m not given to making jokes on science blogs, but what is that green marking on the belly of the Nyctophilus Gouldi depicted in the picture halfway doen the article? Is it some kind of tracking device? For the intrained eye (such as mine) it really, really seems to depict a well endowed specimen flying about while wearing an odd colored profilactic…

  10. #10 hannahsdad
    April 8, 2011

    I live on a clifftop above a backwater wetland of the River Murray in Australia.

    About 5 years ago we were given a bat detector for a week which we put out each evening and pointed out toward a jutting bit of scrub overlooking the wetland.
    You lot here are far more scientifically educated than me so I presume you know how these things work.
    When we got the results we found we had 8 species of bats living here with most represented every night.
    We found this exciting.

    Included in the 8 species was one little fella called Myotis macropus or Large Footed Fishing Bat.
    This we found very exciting.

    Because it was a only the second time this bat had been recorded in South Australia, with the first time being the week before when someone else on a property nearby had the detector at their place.
    And also because the species is, or so I understand, a threatened species.

    That was, as I said, about 5 years ago.

    The following year every backwater swamp alomg the southern section of the river disappeared for 3-4 years leaving smelly polluted weed filled dryland.
    The lack of water for the wetlands was caused by a combination of climate change and naturally occuring drought but primarily by human mismanagement of the river itself.

    Vast quantities of the inflow for the river are consumed for irrigation and during that 3-4 year period the quantity allocated to the river for ‘environmental water’, that is water left over after urban and irrigation needs [or wants] were satisfied, was virtually negligible.

    I don’t know what happened to our little fishing bats, I hope they are still around but it would be, I dont know, ironic is the appropriate word perhaps, if the species was lost almost immediately after it was found.

  11. #11 David Marjanović
    April 8, 2011

    does anyone know why the region in question is called the ‘Central’ Province? It is, after all, located very far to the east indeed on mainland New Guinea.

    I don’t know, but the midline between the easternmost and westernmost points of the country — not the island, but the country of Papua New Guinea — runs through it.

  12. #12 heteromeles
    April 8, 2011

    @11: Talk about hard questions! I looked it up (quickly, online) and got nothing. I have no idea why it’s the central province, although I do suspect that Port Moresby and colonial history have something to do with it.

  13. #13 Andreas Johansson
    April 9, 2011

    Dartian wrote:

    Apologies for going off-topic, but does anyone know why the region in question is called the ‘Central’ Province? It is, after all, located very far to the east indeed on mainland New Guinea.

    I don’t know, but it will have been more central-looking back when the northern half of what’s now Papua New Guinea was a German colony. It was joined with the southern (British/Australian) bit after WWI.

  14. #14 David Marjanović
    April 9, 2011

    it will have been more central-looking back when the northern half of what’s now Papua New Guinea was a German colony

    Oh yeah. I should have thought of that.

  15. #15 Dartian
    April 10, 2011

    Hannahsdad:

    the species is, or so I understand, a threatened species

    Officially at least, it isn’t considered threatened (yet). The IUCN lists Myotis macropus as a ‘Least Concern’ species. But that assessment is mainly based on its relatively wide distribution; not that much detailed information is available regarding its population size.

  16. #16 Calli Arcale
    April 11, 2011

    And *this* is why researchers won’t tell where they found Wollemi Pines. They know that as soon as they did, they’d be gone. Very sad indeed.

    I’ve been greatly enjoying this series on bats! Bats are amazing creatures. I was at our local zoo recently, where they have a fruit bat exhibit, and there was one grooming itself in a conveniently visible location. (The bats aren’t always visible; this zoo has done an excellent job of designing the habitats, and the animals don’t have to be visible if they don’t want to be. Flip side: they try to design the exhibits so the animals will *want* to be visible. And it usually works.) I pointed it out excitedly to my children, saying “you can even see its fingers!” A teenager nearby overheard and was puzzled. “It has fingers?” “Yeah,” I said. “It’s how the wing works.” She had honestly never looked at a picture of a bat closely enough to see that before.

  17. #17 Ashley
    April 13, 2011

    This is a really interesting thing its neat to know about big-eared bats. And that they are wiping out Colony!

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