Friday, October 27, 2006

Terror birds

Were you to visit sunny Texas 5 million years ago (cough cough), a giant predatory bird, 3 m tall with a head 70 cm long, might have kicked you down and eviscerated you with its immense hooked bill. I am of course talking about phorusrhacids, sometimes called terror birds, the mostly large, flightless predatory birds of the prehistoric Americas and elsewhere, and as you’ll know if you’ve been keeping an eye on the news, a new and exciting member of the group was described last week in Nature (Chiappe & Bertelli 2006). I like to promote the idea that big eagles are awesome powerful predators, well able to tackle and kill surprisingly big mammals (see When eagles go bad and The biggest eagle, part I) but, needless to say, even big eagles pale into near-insignificance next to these distant cousins.

Yet again, it’s funny how things work out. My life right now mostly consists of job-hunting, but because of the various part-time teaching jobs I have I am always working on powerpoint presentations. Last week I put the finishing touches to ‘The evolution of birds in the Cenozoic’, and of course I added a section on phorusrhacids. Now that Chiappe & Bertelli (2006) has been published I will have to make a few changes.

I’ve always been very interested in phorusrhacids and, unlike many of the animals I write about (the shame), I have some experience with them. What are they? They are universally agreed to be relatives of the living seriemas (Cariamidae), but differ from them in having a far more robust bill and jaws, smaller bony processes on the humerus, and a narrower pelvis. They also, of course, grew to a much larger size. The two living seriema species are South American, but members of similar, closely related groups (the bathornithids and idiornithids) inhabited North America from the Eocene to the Miocene and Europe from the Eocene to the Oligocene. I have a lot more to say on the affinities of all of these birds: you’ll have to wait for a future post (Giant hoatzins of doom: the ‘South American land bird’ theory).

The various phorusrhacid genera and species have been reviewed twice in the past 50 years. Patterson & Kraglievich (1960) looked at the Pliocene species and mostly discussed the relatively obscure taxa Hermosiornis and Onactornis (the latter is currently regarded as synonymous with Devincenzia). Perhaps because their study was written in Spanish [with only a brief English summary], it has been widely overlooked. It also has far too few illustrations and – to quote Storrs Olson (1985)* – is ‘a nightmare of typographical errors’ (p. 145). Apparently it was meant to be just the preliminary nomenclatural part of a much larger revision of the whole group by Bryan Patterson, but this never appeared. Fortunately, Alvarenga & Höfling (2003) looked at phorusrhacids anew and reviewed all the taxa, providing information on historical taxonomy, palaeoecology, and phylogenetic affinities. While they didn’t perform a cladistic analysis, this is pretty much the sort of study we have long needed, and the fact that it is widely and freely available on the web as a pdf (go here) means that it will enjoy widespread consultation (if only all publishers did this with academic papers: remember, the availability of pdfs is never under the control of authors). For now, it is the ‘standard work’ on the group.

* More than any other person in zoological writing, Olson has produced an impressive list of scathing quotes and insults. One day I’ll make a point of collecting them all together.

Alvarenga & Höfling (2003) grouped phorusrhacids into five subgroups; the small, gracile psilopterines, known from the Palaeocene to the Pliocene and including the oldest of all phorusrhacids; the mid-sized, shallow-skulled, gracile-legged mesembriornithines of the Miocene-Pliocene; the mid-sized patagornithines of the Oligocene, Miocene and Pliocene; the gigantic, robust brontornithines of the Oligocene and Miocene; and the mostly large, gracile-legged phorusrhacines of the Miocene, Pliocene and Pleistocene. The last group was the only one to make it into the Pleistocene, and the only group to invade North America. The smallest psilopterine was about 70 cm tall while the biggest brontornithines and phorusrhacines were about 3 m tall and among the biggest birds of all time. Mesembriornithines were, proportionally, about as long-legged as emus or rheas, while brontornithines included the most stocky-legged birds of them all.

It is of minor frustration that the phorusrhacids we hear about the most are among the most poorly known. The ‘best known’ phorusrhacid, the one featured in every single prehistoric animal book, is Phorusrhacos longissimus from the Miocene of Argentina. But it’s only ‘best known’ because it was the first member of the group to be named, and compared to a number of far more obscure species, it is poorly known and mysterious. Of its skull, for example, we only have the lower jaw and some fragments of cranium. Florentino Ameghino (1854-1911), the famous Argentine zoologist/palaeontologist who discovered and named it and several other phorusrhacids, did write in 1895 of seeing a complete skull, encased in rock in the field, but he was only able to sketch it and recover fragments. His drawing is of a complete, pristine skull and it is on the basis of this that an entire replica skull has been produced (see accompanying image). Compare this with the patagornithines Patagornis and Andalgalornis, for example, both of which are known from awesome, complete skulls with good, associated, near-complete skeletons.

Incidentally, you might have seen the name Phorusrhacos written as Phororhacos (and Phorusrhacidae written as Phororhacidae). The former is the older, and thus correct, spelling, coined by Ameghino in 1887. At this time Ameghino thought that he had discovered a new herbivorous toothless mammal, perhaps a sloth, and Phorusrhacos was named to mean something like ‘branch holder’. It’s also a switched-round version of Rhacophorus, a genus of arboreal Asian frogs: that name also meaning ‘branch holder’. This isn’t a coincidence – Ameghino did this sort of thing with lots of names. When in 1889 Ameghino discovered that Phorusrhacos was really a bird, he changed the name to Phororhacos, as this (apparently) means something like ‘rag bearer’ and Ameghino regarded this as more appropriate etymologically than ‘branch holder’ (I regret that I have no idea why, however). Changing of names like this is not allowed under the guidelines of the ICZN and hence Phororhacos – still used by some people even today – should be suppressed. An ICZN ruling of 1992 made Phorusrhacos and Phorusrhacidae the officially accepted spellings.

Speaking of Phorusrhacos, the painting at top - depicting this taxon - is one of the most famous phorusrhacid renditions ever (it's borrowed from the Burian gallery), and was produced by one of the 20th century's greatest palaeo-artists, Zdenek Burian (1905-1981). The colour scheme used in the painting has been widely copied by other artists: for a discussion on this subject go here.

The new phorusrhacid described by Chiappe & Bertelli (2006) consists only of a skull and some leg bones (other elements might be known, but aren’t mentioned), but is significant for its size and the completeness of the skull. Discovered in Miocene rocks of Comallo, Argentina, it appears to be a phorusrhacine closely related to Devincenzia, another of those obscure taxa known from pretty good remains. For reasons that I don’t quite grasp, the new specimen isn’t named (whether it represents a new taxon that will be named elsewhere, or whether it proves referable to an already-named form [like Devincenzia] is not stated) and currently only has the accession number BAR 3877-11 (BAR = Museo Asociación Paleontológico Bariloche, Argentina). Anyway, with a total length of 71 cm, BAR 3877-11 possesses the largest avian skull. What is slightly odd about Chiappe & Bertelli’s paper is that they continually refer to giant phorusrhacids as the ‘largest birds known’. While it is certainly true that some of these birds – reaching a total height of about 3 m and a weight of 350 kg or more – were immense, they were similar in size to, and perhaps smaller than, the biggest aepyornithids and dromornithids, so this isn’t clear cut.

And I have to stop there. More on phorusrhacids in the next post, looking at brontornithine lifestyle, mesembriornithine running speed (were they the fastest-running birds ever?), and the anatomy of feet and skulls [available here].

PS - I intended to add more images to this post, but Im having trouble in getting blogger to upload them. For the latest news on Tetrapod Zoology do go here.

Refs - -

Alvarenga, H. M. F. & Höfling, E. 2003. Systematic revision of the Phorusrhacidae (Aves: Ralliformes). Papéis Avulsos de Zoologia, Museu de Zoologia da Universidade de São Paulo 43, 55-91.

Chiappe, L. M. & Bertelli, S. 2006. Skull morphology of giant terror birds. Nature 443, 929.

Olson, S. L. 1985. The fossil record of birds. In Avian Biology, Volume III, pp. 79-238.

Patterson, B. & Kraglievich, J. L. 1960. Sistematica y nomenclatura de las aves fororracoideas del Plioceno Argentino. Publicaciones del Museo Municipal de Ciencias Naturales y Tradicional de Mar del Plata 1, 1-52.

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Wednesday, October 25, 2006

Lunging is expensive, jaws can be noisy, and what’s with the asymmetry? Rorquals part III

In the previous post I discussed the basic anatomy and behaviour involved in lunge-feeding, a style of predation practiced by rorquals, the biggest, fastest and most dynamic of baleen-bearing cetaceans. By engulfing literally tons of water within a unique, flexible buccal pouch, rorquals change shape from ‘a cigar shape to the shape of an elongated, bloated tadpole’ (Orton & Brodie 1987, p. 2898). Their feeding style is anything but passive: Paul Brodie, an expert on rorqual feeding, has described it as ‘the largest biomechanical action in the animal kingdom’. After discussing rorquals with whale expert Nicholas Pyenson, my good friend Matt Wedel, in one of several blog posts on rorquals and other mysticetes (thats three separate links there), provided the most excellent quote…

The big baleen whales pick their targets and engulf them with their giant jaws and extensible mouth/throat region. They are often feeding on swarms of krill that measure kilometers in extent. Rather than think of big whales as filter feeders, we should think of them as predators that take bites off of superorganisms that are hundreds of times larger. The fact that the krill are strained out of the water by the baleen is a matter of processing - it comes after the whale has taken a bite.

That’s great: I’ll be stealing it for use in lectures. The photo at top features the immense jaws of an Antarctic blue whale, kept at Washington D.C.s Garber Facility (part of the National Museum of Natural History), and is borrowed from here on Matt's blog site.

Recent studies show that lunge-feeding is not just dynamic, it is also extremely expensive in metabolic terms, and even though rorquals glide as they lunge (thereby conserving some energy), it still seems that lunge-feeding is so energetically costly that constraints are imposed on rorqual behaviour. Theoretically, large-bodied species store more oxygen thanks to their size, and therefore have a higher theoretical aerobic dive limit (TADL). Indeed in marine mammals as a whole there is a trend of increasing dive depth and duration with increasing body size. If we look at the largest rorquals – the blue and fin – we find TADLs of 31.2 and 28.6 minutes. Yet the actual aerobic dive limits of the two species are respectively 7.8 and 6.3 minutes (Croll et al. 2001). For comparison, right whales – which weigh about half as much as blue whales – spend about twice as long foraging under water as blue whales. To quote Acevedo-Gutiérrez et al. (2002) ‘the largest predators on earth have the shortest dive durations relative to their TADL’ (p. 1747). Note also that rorquals don’t dive deep for their size: fin whales have been reported to dive down to 470 m, but that’s not deep for such a big animal (total length 18-25 m), nor were the dives in question long in duration at less than 13 minutes [adjacent photo, from the Right Whale Aerial Surveys site, shows a feeding Fin whale].

Goldbogen et al. (2006) studied the kinematics of diving and lunge-feeding fin whales and showed that the rapid acceleration attained during lunge-feeding is immediately met by a relatively larger deceleration, presumably caused by the opening of the buccal pouch. The whales also rolled their bodies during lunging and may in fact spin about their long axis during feeding events, and at the bottom of a feeding dive a whale undertook a series of vertical excursions. It seems that the rapid acceleration and deceleration, and the dynamic movement, involved in lunge-feeding is highly costly, forcing rorquals to limit their dive time, and to increase the time that they need to spend at the surface recovering (Acevedo-Gutiérrez et al. 2002).

Some very interesting implications result from this expensive feeding style. Because lunge-feeding is so costly, it is likely only profitable where prey concentrations are high. Lunge-feeding rorquals cannot make a living anywhere there is suitable prey, therefore, but are ecologically tied to productive regions such as submarine canyons and the Southern Boundary of the Antarctic Circumpolar Current. A blue whale has been estimated to require one metric ton of krill per day.

When this is combined with the fact that some of the prey that rorquals depend upon, such as krill, are declining, it becomes clear why certain rorqual populations are struggling to recover from the days of commercial whaling. Indeed work on African hunting dogs Lycaon pictus has shown that high metabolic costs incurred during predation cause some species to be competitively inferior to others, forcing their populations to remain at low levels (Gorman et al. 1998). So lunge-feeding is a high-maintenance activity, and we should not be surprised that lunge-feeding rorquals that lunge-feed only on specific prey species are endangered, and liable to decline.

Here it’s worth noting that different rorqual species specialize on different prey, though some (the minkes and the fin whale) seem to be opportunists. Sei whales specialize on crustaceans, in particular on copepods, and blue whales are specialist krill predators (Sigurjónsson 1995). Furthermore, not all rorqual species feed by lunging – the sei in particular uses a technique called skimming, whereby the whale keeps its mouth slightly open and moves forward through a body of prey at a continuous speed. It would be interesting to know how the morphology, kinematics and energetics of the sei compare to those of lunge-feeding rorquals, but so far as I know these issues remain largely unstudied. We do know that its baleen is particularly fine, allowing it to filter the comparatively small copepods [adjacent photo, also from the Right Whale Aerial Surveys site, shows a feeding sei. Its feeding on its side. Hmm].

Thanks to the work of August Pivorunas, Paul Brodie and colleagues, the engulfing mechanism of rorquals has been reasonably well understood since the 1970s. However, questions always remained. How is it that, during lunge feeding, agile, highly reactive prey remain within the mouth cavity prior to the mouth’s closure? Man-made devices of similar size are incapable of retaining prey without them escaping prior to the devices’ closure (Brodie 1978). When a rorqual carcass is processed at a whaling station, the soft tissue of the throat is removed by flensing. Using cables and straps, the jaws are then winched open, and the tendons and muscles holding the mandibles in place are then cut, freeing the jaw from the skull. Because the jaw is winched open without the very heavy throat tissue attached, its movement during the procedure approximates the natural movement of the jaw when the animal is alive and underwater. As the jaw is winched open ‘a familiar sequence of sounds was observed to originate from the jaw apparatus … a growl or rumble, a low hydraulic suction noise, following by a powerful knock, the latter seeming to emanate from the tip of the jaw’ (Brodie 1993, p. 546). The noise reverberated throughout the jaw, making the entire structure vibrate. Unusual loud noises have been reported from live, feeding fin whales, so what Brodie reported apparently occurs in live whales, and not just dead ones.

What might cause these noises? Could it be that the articular condyles of the jaw bones were grinding against the bones of the skull? Well, no, as large masses of collagen and lipid are sandwiched between the lower jaw and skull, and in the specimens Brodie examined there was no suggestion that this tissue had been compromised. Could it be that the jaw tips were grinding together? Again, no, as soft tissue separates the jaw tips and, anyway, the jaw tips were being forced apart when the noises were being made, not together. Brodie (1993) concluded that the noise was a consequence of the stretching apart of a synovial capsule located between the jaw tips. And, funnily enough, here we have something that is of direct relevance to all of us (well, most of us. Well, those of us who have heard our joints make crack noises).

As synovial capsules are forced apart, a partial vacuum forms in the joint cavity. Adjacent water vapour and blood gases from surrounding tissues rush to fill the vacuum, and as it collapses a noise results. Such noises range from low rumbles to loud knocks. This process is termed pseudocavitation (to distinguish it from cavitation: the process whereby the medium actually ruptures), and I’ve just realized that this solves one of the greatest mysteries in all of biomechanics: why our knuckles crack. I can’t tell you how many times I’ve sat around with colleagues, pondering this very question.

If the lower jaws of fin whales really do make a loud bang or crack when they are opened to full gape, we can speculate that the whales might use this to help them retain prey within the mouth during engulfment. Captured prey would be startled away from the jaw edges by the noises, and this isn’t unlikely given that we’ve long known that rorquals exploit the behavioural traits of their prey to concentrate them during predation (it is well known that humpbacks use bubbles to encircle prey, and in fact fin and Bryde’s whales have been reported doing this too). To my knowledge, the ‘noisy jaw’ hypothesis has only been proposed for fin whales. Is it unique to this species, or practiced more widely?

And speaking of fin whales…. generally speaking, tetrapods have symmetrical bodies and symmetrical arrangements of pigmentation. Why then are fin whales asymmetrical? Mostly dark on the left side of the head (this goes for the baleen and the left side of the tongue), they are mostly light on the right side (and, again, this goes for the baleen and the right side of the tongue). While individuals belonging to various species will sometimes exhibit asymmetrical pigmentation (and rorquals, such as minkes and sei whales, are among them), fin whales are consistently like this: all of them.

Does this serve a function? Mostly it has been thought that it is something to do with counter-shading: if the whale swims anti-clockwise around its prey it might be camouflaged against the water and hence invisible, or is it that it swims clockwise around its prey, frightening them with its vivid whiteness and causing them to bunch up? Both ideas have been proposed (Ellis 1982). Most recently, cetologists seem to have favoured the idea that fin whales actually swim on their right side while lunge-feeding, thereby using a sort of rotated counter-shading. I’ve seen photos that apparently support this idea of right-sidedness, but I don’t know if there any good studies on the subject. There is widespread evidence for handedness across Tetrapoda (including in whales), so does this mean that all fin whales are right-handed, or left-handed?

That’s it on rorquals for now, though I plan at some stage to talk about the recently resurrected and recently discovered taxa, such as the Pygmy blue whale, Antarctic minke and Omura’s whale. And what is it with the name Balaenoptera musculus?

One last thing. I can’t go without relating the amazing tale of how I personally encountered Brodie’s 1993 paper ‘Noise generated by the jaw actions of feeding fin whales’. While collecting papers at Southampton University’s Boldrewood Biomedical Science Library one day, I decided to find and photocopy this paper. All I knew was that it had been published in Canadian Journal of Zoology. I had no idea what volume it had been published in, nor in what year it had been published. The problem is that the Boldrewood library has a near-complete run of Canadian Journal of Zoology, with many metres of shelving being taken up by volume after volume after volume. In a futile effort to begin my search, I pulled out a single volume, at random, and opened it, at random. I had found the paper. Ha – and people tell me I’m not psychic! :)

For the latest news on Tetrapod Zoology do go here.

Refs - -

Acevedo-Gutiérrez, A., Croll, D. A. & Tershy, B. R. 2002. High feeding costs limit dive time in the largest whales. The Journal of Experimental Biology 205, 1747-1753.

Brodie, P. F. 1978. Alternative sampling device for aquatic organisms. Journal of the Fisheries Research Board of Canada 35, 901-902.

- . 1993. Noise generated by the jaw actions of feeding fin whales. Canadian Journal of Zoology 71, 2546-2550.

Croll, D. A., Acevedo-Gutierrez, A., & Tershy, B. R. & Urbán-Ramírez, J. 2001. The diving behavior of blue and fin whales: is dive duration shorter than expected based on oxygen stores? Comparative Biochemistry and Physiology 129A, 797-809.

Ellis, R. 1982. The Book of Whales. Alfred Knopf, New York.

Goldbogen, J. A., Calambokidis, J., Shadwick, R. E., Oleson, E. M., McDonald, M. A. & Hildebrand, J. A. 2006. Kinematics of foraging dives and lunge-feeding in fin whales. The Journal of Experimental Biology 209, 1231-1244.

Gorman, M. L., Mills, M. G., Raath, J. P. & Speakman, J. R. 1998. High hunting costs make African wild dogs vulnerable to kleptoparasitism by hyaenas. Nature 391, 479-481.

Orton, L. S. & Brodie, P. F. 1987. Engulfing mechanisms of fin whales. Canadian Journal of Zoology 65, 2898-2907.

Sigurjónsson, J. 1995. On the life history and autecology of North Atlantic rorquals. In Blix, A. S., Walløe, L. & Ulltang, Ø. (eds) Whales, Seals, Fish and Man. Elsevier Science, pp. 425-441.

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Tuesday, October 24, 2006

From cigar to elongated, bloated tadpole: rorquals part II

More on rorquals (for part I go here), this time looking at the basics of their morphology and feeding behaviour. The rostrum in rorquals is long and tapers to a point (though it is comparatively broad in blue whales) and, in contrast to other mysticetes, a stout finger-like extension of the maxillary bone extends posteriorly, overlapping the nasals and abutting the supraoccipital (the shield-like plate that forms the rear margin of the skull). The dorsal surfaces of the frontals (on the top of the skull) possess large depressions while the ventral surfaces of the zygomatic processes (the structures that project laterally from the cheek regions) are strongly concave, again unlike the condition in other mysticetes.

Rorqual lower jaws are immense, beam-like bones that bow outwards along their length. The symphyseal area (the region where the jaw tips meet) is unfused, as is the case in all mysticetes (even the most basal ones) but not other cetaceans, meaning that the two halves of the jaw can stretch apart at their tips somewhat. Exceeding 7 m in blue whales, rorqual lower jaws are the largest single bones in history (ha! Take that Sauropoda).

A section of blue whale jaw was once ‘discovered’ at Loch Ness and misidentified as the femur of an immense, hitherto undiscovered tetrapod. Occasionally rorqual skulls have been discovered in which the long lower jaws have been stuck wedged inside various of the skull openings and with their tips protruding like tusks. People unfamiliar with cetacean skulls have then naively assumed that the skull belonged to some sort of tusked prehistoric sea monster. Ben Roesch discussed cases of this (go here), and also noted the case of the Ataka carcass of 1956: a giant beached animal possessing divergent ‘tusks’ that are in fact the separated halves of a rorqual’s lower jaw (see adjacent image).

I’ve come across another case of this sort of thing. The accompanying newspaper piece, from The Telegraph of June 29th 1908, features a skull trawled up by the Aberdeen vessel Balmedie (sailing out of Grimsby), and thought by the article’s writer to be that of ‘some prehistoric monster’, apparently with tongue preserved. It’s clearly a rorqual skull, and the pointed, narrow rostrum and posterior widening of the mesorostral gutter indicates that it’s a minke whale skull.

Moving back to the morphology of the rorqual lower jaw, a tall, well-developed coronoid process – way larger than that of any other mysticete – projects from each jaw bone and forms the attachment site for a tendinous part of the temporalis muscle, termed the frontomandibular stay.

All of these unusual features are linked to the remarkable feeding style used by rorquals. How do they feed? Predominantly by lunge-feeding (also known as engulfment feeding): by opening their mouths to full gape (c. 45º), and then lunging into a mass of prey. Those depressed areas on the frontals and zygomatic processes have apparently evolved to allow particularly large temporalis and masseter muscles, the muscles involved in closing the jaw. The frontomandibular stay provides a strong mechanical linkage between the lower jaw and skull and seems primarily to amplify the mechanical advantage of the temporalis muscles.

As a rorqual lunge-feeds, an immense quantity of water (hopefully containing prey) is engulfed within the buccal pouch, transforming the whale from ‘a cigar shape to the shape of an elongated, bloated tadpole’ (Orton & Brodie 1987, p. 2898). While a rorqual uses its muscles to open its jaws, the energy that powers the expansion of the buccal pouch is essentially provided by the whale’s forward motion, and not by the jaw muscles. In other words, the engulfing process is powered solely by the speed of swimming. Orton & Brodie (1987) noted that the engulfed water ‘is not displaced forward or moved backward by internal suction, but is simply enveloped with highly compliant material’ (p. 2905). Rorquals do not, therefore, set up a bow wave as they engulf.

A rorqual may engulf nearly 70% of its total body weight in water and prey during this action, which in an adult blue whale amounts to about 70 tons (Pivorunas 1979). In order to cope with this, the tissues of the buccal pouch must be highly extensible and able to cope with massive distortion. The ventral surface of the pouch is covered by grooved blubber, on which the 50-90 grooves extend from the jaw tips to as far posteriorly as the umbilicus. The ventral grooves can be extended to 4 times their resting width, and to 1.5 times their resting length. Internal to the grooved blubber is the muscle tissue of the buccal pouch, and this is unique, containing large amounts of elastin, and consisting of an inner layer of longitudinally arranged muscle bands and an outer layer where the bands are obliquely oriented (Pivorunas 1977).

When a rorqual lunges, delicate timing is needed, otherwise the buccal pouch will rapidly fill with seawater and not with prey. How then do rorquals get their timing just right? It seems that rorquals possess batteries of sensory organs within and around the buccal pouch: there are laminated corpuscles closely associated with the ventral grooves that might serve a sensory function, and located around the edges of the jaws, and at their tips, are a number of short (12.5 mm) vibrissae. Long assumed to be vestiges from the time when whale ancestors had body hair, it now seems that these structures have a role in sensing vibrations.

Once a mass of prey is engulfed, a rorqual then has to squeeze the water out through its baleen plates while at the same time retaining the prey. Rorqual baleen plates number between 219 to 475 in each side of the jaw (the number of plates is highly variable within species, with sei whales alone having between 219 to 402), and each plate ranges in length from 20 cm (in the minkes) to 1 m (in the blue). As the whale stops lunging forward, the pressure drops off, allowing deflation of the buccal pouch. Passive contraction of the blubber grooves and active contraction of the muscle layer within the buccal pouch also occurs at this time.

For an outstanding sequence of photos illustrating engulfment in action, see Randy Morse’s photos of a feeding blue whale here.

So that’s the basics. But there’s so much more to the subject than this. How is it that, during lunge feeding, agile, highly reactive prey remain within the mouth cavity prior to the mouth’s closure? Why do some rorquals make loud noises during lunge-feeding? Why, given their immense size and theoretical high aerobic dive limit, do big rorquals not spend more time lunge-feeding beneath the surface? Why do some rorquals exhibit strongly asymmetrical patterns of pigmentation? And don’t forget that not all rorquals lunge-feed. More on these issues in the following post.

The painting at top is from Valter Fogato's site.

For the latest news on Tetrapod Zoology do go here.

Refs - -

Orton, L. S. & Brodie, P. F. 1987. Engulfing mechanisms of fin whales. Canadian Journal of Zoology 65, 2898-2907.

Pivorunas, A. 1977. The fibrocartilage skeleton and related structures of the ventral pouch of balaenopterid whales. Journal of Morphology 151, 299-314.

- . 1979. The feeding mechanisms of baleen whales. American Scientist 67, 432-440.

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Monday, October 23, 2006

A 6 ton model, and a baby that puts on 90 kg a day: rorquals part I

I’ve said it before but it’s worth saying again: everyone interested in animals is, I assume, fascinated by whales. All secondarily aquatic tetrapods are neat, but here we have a group that has evolved giant size, suspension feeding, macropredation, deep-diving and echolocation, among other things. Right now, I have rorquals on my mind, and I’m not quite sure why: I haven’t been doing any research on them lately, nor have they been in the news or anything*. However, later this week my family and I are visiting the Natural History Museum (London) and I’m particularly looking forward to showing Will (who’s 5) the life-sized Blue whale Balaenoptera musculus model that hangs in the Mammal Hall (the room formerly known as the Whale Hall). I’m so interested in this model that I feel it worthy of a short digression.

* Bar the news that Iceland is resuming low-level whaling. Yay Iceland.

Late in the 1920s plans to replace the old whale hall of the British Museum (Natural History) were fulfilled. The new, steel-girdled hall finally allowed the 1934 display of the Blue whale skeleton [image above, from here] that had been kept in storage for 42 years due to lack of space. Measuring 25 m in length, the animal had stranded at Wexford Bay, SE Ireland, in 1891. It – as in, the skeleton alone – weighs over 10 tons. But some people at the museum wanted more, and in 1937 taxidermist Percy Stammwitz (1881-1954) made the bold suggestion that a life-sized model of a Blue whale could be constructed within the Whale Hall itself. Later that year Stammwitz and his son, Stuart, began work on the project, their technical advisor being cetologist Francis C. Fraser (1903-1978).

Scaling up from a clay model, a wooden frame was constructed, and this was then covered in wire mesh and plaster. A trapdoor on the stomach was constructed for (I presume) internal maintenance, though apparently the workmen would sneak inside the model for secret smoking. On several occasions I’ve heard rumours that a time capsule was left inside this trapdoor before it was sealed: Stearn (1981) made no mention of this specifically, but did write that a telephone directory and some coins were left inside (p. 132). The completed model weighed between 6 and 7 tons and, when the time came for the whale to be painted, Stammwitz and Fraser disagreed, eventually choosing bluish steel-grey. Completed in December 1938, it was the largest whale model ever constructed though larger models, constructed from the same design templates, have since been produced by several American museums [adjacent image from here].

What are rorquals? They are the eight or so Balaenoptera species of the mysticete family Balaenopteridae*, all of which open their jaws wide to engulf masses of prey and possess a highly distensible throat pouch and extensible longitudinal grooves on the throat and belly. They occur in seas worldwide and range from 6 to 30 m in length. The only other living balaenopterid** is the Humpback Megaptera novaeangliae, and it is generally regarded as the sister-taxon to the rorquals. I’ve seen two explanations for the term rorqual. The commonest is that it derives from the Norwegian rørhval and means ‘grooved whale’ – a reference to those longitudinal grooves. The less common explanation is that it originated from the French for ‘red throat’, this supposedly being a reference to the reddish colour visible between the throat grooves when the whale’s buccal pouch is extended (Berta & Sumich 1990).

* Most books on whales state that there are five rorqual species. As with so many tetrapod groups, the number of recognised species has increased in recent years, both as ‘old’ species have been resurrected from synonymy (Antarctic minke B. bonaerensis and Pygmy bryde’s B. edeni), and as new species have been described (Omura’s whale B. omurai).

** Some workers have included the Grey whale Eschrichtius robustus within Balaenopteridae. It is mostly agreed, however, that Eschrichtius belongs to a small clade (Eschrichtiidae) best regarded as the sister-taxon to Balaenopteridae.

Rorquals grow fast, reaching sexual maturity at between 5 and 12 years of age in the larger species. They can produce up to 1.5 calves per 2-year period, though three years between calves is probably more normal. Pregnant females increase their weight by 26% and, thanks to lipids stored in their visceral fat and blubber, increase their total energy budget by a staggering 80% (Víkingsson 1995). After a pregnancy of 10-13 months, babies are suckled for 4-10 months and (in blue whales) are provided with 200 litres of milk a day. Unsurprisingly, babies increase their weight substantially during this time, with a 2-3 ton newborn blue whale putting on 90 kg a day, and reaching 20 tons by the time it is weaned. They are the fastest growing baby mammals. Rorquals are long-lived, with minkes B. acutorostrata reaching their forth or fifth decades, Sei B. borealis surviving to 65 or so, and Fins B. physalus to 85 or 90, or possibly 100. Incidentally, right whales (balaenids) are thought to survive into their second century, but they’re not rorquals.

We all know that rorquals are big, that they possess baleen, and that they feed by engulfing crustaceans, small fish and other prey. They spend summer in the polar regions, where they feed and put on weight, and then they migrate in the winter to the tropics, where they breed and give birth to their enormous calves… but they don’t _all_ do this, with some populations of some species being non-migratory. Of course, there’s more, a lot more, and in the next few posts I’d like to introduce a few details that you might not have encountered before… unless, that is, you’re a cetologist, or a close friend of one.

Thanks – mostly – to aerial photography, most of us are now familiar with the true body shape of live rorquals. They are shockingly gracile and incredibly long-bodied, with a shape that (when seen in dorsal view) has been likened to that of a champagne flute. While people had known this for a while (Roy Chapman Andrews wrote in 1916 of the Fin whale’s ‘slender body … built like a racing yacht’, for example), what may or may not be surprising is that only recently have people in general come to realize that rorquals are shaped like this. Basing their reconstructions on beached carcasses, or on rorquals killed by whaling vessels, artists and scientists had previously thought that rorquals were stouter, with fat bellies and flabby throats. Rorquals were still being depicted this way as recently as the 1960s, as in (for example) the excellent paintings and drawings of Sir Peter Scott [see above, borrowed from the Wildlife in Danger Brooke Bonds card set].

By photographing live sei and minke whales, underwater, from close range, Gordon Williamson (1972) argued that the traditional ‘baggy-throat’ reconstructions failed to show the true body shape of the animals. His drawings, reconstructed from his photos (which invariably failed to capture the entire animal in the frame), were dead accurate and among the first to depict rorquals in this way. Williamson’s whales were all captured, by harpoon, from a commercial whaling vessel. No explosive was placed in the harpoon head (normally, the harpoon head explodes within the body of the whale), so a harpooned whale was not killed immediately and was simply tethered to the ship. As it swam around, gradually tiring, Williamson approached it in the water and took his photos [the accompanying image, showing a young rorqual that beached in Florida in 2002, is borrowed from].

More on rorquals in the next post, this time focusing on the biomechanics of feeding: From cigar to elongated, bloated tadpole: rorquals part II. For the latest news on Tetrapod Zoology do go here.

Refs - -

Berta, A. & Sumich, J. L. 1999. Marine Mammals: Evolutionary Biology. Academic Press, San Diego.

Stearn, W. T. 1981. The Natural History Museum at South Kensington. Heinemann, London.

Víkingsson, G. A. 1995. Body condition of fin whales during summer off Iceland. In Blix, A. S., Walløe, L. & Ulltang, Ø. (eds) Whales, Seals, Fish and Man. Elsevier Science, pp. 361-369.

Williamson, G. R. 1972. The true body shape of rorqual whales. Journal of Zoology 167, 277-286.

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Thursday, October 19, 2006

Giants, goblins, unihumans and all that

Today, my good friend Bronwen introduced me to a very interesting article that appeared, just a few days ago, on the BBC news website. Titled ‘Human species may split in two’, it discusses Oliver Curry’s research on the possible future evolution of Homo sapiens (you can access the article here). It’s not a new area of speculation: see, for example, Stebbins (1970) and Dixon (1990), but Curry’s take on the subject is, err, innovative, and already various bloggers have been making hilarious comments on it.

Apparently, human evolution is due to ‘peak’ in the year 3000 (quite what that means I’m not entirely sure), then there will be some sort of decline due a ‘dependence on technology’, and then, in the distant future, H. sapiens will diverge into two separate taxa: one consisting of tall, slim, highly intelligent super-hominids, and the other consisting of dim-witted, ugly, squat goblin-like hominids (see accompanying picture, taken from the BBC website). In other words, we’re talking about something a bit like the eloi and morlocks of Well’s The Time Machine.

There’s more in the article: it also discusses what will happen within human evolution over the next 1000 or so years. Symmetry in facial features is apparently set to improve, and squarer jaws, deeper voices and larger penises in men will evolve, as will smoother skin, more pert breasts and glossier hair in women. Racial differences will disappear as we all merge into one homogenous global gene pool.

Curry is of the London School of Economics, and is fairly well known for writing on evolutionary theory and how it relates to moral philosophy and so on. Anyway, many – but not all – media reports announcing new science discoveries appear because a new technical paper has appeared, so I immediately wondered whether Curry’s research might have appeared in a technical journal… Journal of Human Evolution perhaps, or Proceedings of the National Academy of Sciences, or Nature. Errr, no, Dr Curry ‘carried out the report for men’s satellite TV channel Bravo’. Ah. Oh dammit, I knew it was too good to be true :)

You don’t need me to tell you that there is little here that warrants a serious look. It’s science fiction. There is – to my knowledge – no indication that humanity might somehow diverge into beautiful smart giants vs stupid ugly goblins, nor, in the short term, are there good reasons for thinking that men might be evolving bigger penises, squarer jaws or deeper voices, or that women’s hair is becoming glossier, their breasts more pert and so on (please correct me if you know otherwise). Supposedly, there are a number of derived morphological characters within H. sapiens that make some populations, and some individuals, appear more recently evolved than others (they include absence of ear lobes, blue eyes and an asymmetrical crown), but is there any indication that these characters are becoming more prevalent? No. I might seem a bit naïve here, but isn’t there a general agreement that the absence of selection within our species means that we are no longer evolving? Sure, the potential for future evolution is always there, but we don’t yet have information on that.

Will racial differences disappear due to interbreeding? Evidence apparently shows that cultural diversity is decreasing, and leading experts on biodiversity, such as Duke University’s Stuart Pimm, have been quoted as saying that humans are becoming more homogenous. Some articles on this much-asked question have speculated that the result might be the homogenous ‘unihuman’ (see adjacent reconstruction), leading us to become less resistant to diseases and increasingly unable to cope with potential environmental changes.

While this might seem logical, I think people fail to realise just how much integration there would have to be in order for H. sapiens to become morphologically uniform. Sure, people of different racial origins are more inclined to interbreed than ever before, but this still leaves populations of literally millions of people that will, actually, never mingle with other populations of literally millions of people. We (as in, we members of H. sapiens) are not all jetting around the world, crossing oceans, and breeding with people from other continents. The vast majority of us don’t really move much, nor will we. There is a possible analogue in studies on language: some research indicates that dialects are becoming more distinct, not less so, and in an age where the world is becoming proverbially smaller, I wonder if increasing numbers of populations may become more provincial, not less so.

Anyone that knows me knows that I’m a big fan of Dougal Dixon and his three books on hypothetical future evolution (for the latest evidence go see Naish does Dixon, if you’ll pardon the expression at my flickr site). Naturally I can’t therefore help but compare Curry’s future humans with the hominids that Dougal invented for Man After Man (1990). In a future where all megafauna is extinct and where technologically advanced humans are highly skilled at genetic engineering, future people 500 years hence genetically create ungulate-like grassland people, cold-weather tundra people, scansorial forest and woodland people, and gilled, seal-like aquatic people (Dixon 1990). A future ice age and magnetic reversal then lead to the collapse of civilization, and for the next several million years the book follows the evolution of the genetically modified humans as they diversify and evolve new species. We see the evolution of eusocial desert humans, high-altitude snow humans that have co-evolved with telepathic woodland people, and later still giant sloth people and the saber-toothed people that prey on them. And more. Of course, it doesn’t pretend to be anything other than a work of science fiction.

Anyway, time to move on. For the latest news on Tetrapod Zoology do go here.

Refs - -

Dixon, D. 1990. Man After Man: An Anthropology of the Future. Blandford, London.

Stebbins, G. L. 1970. The natural history and evolutionary future of mankind. The American Naturalist 104, 111-126.

Wednesday, October 18, 2006

The first new European mammal in 100 years? You must be joking

So, Europe has a brand-new species of hitherto-undiscovered mammal, the Cypriot mouse Mus cypriacus. That’s great, but what has interested me in particular is the claim made in many articles that the Cypriot mouse is ‘the first new European mammal to be discovered in more than 100 years’ (go, for example, here or here). Sad to say, this quote wasn’t invented by journalists, but apparently comes right from the mammalogists who described the species.

One internet article on the discovery states that it ‘overturns the widely held belief that every living species of mammal had been identified in Europe’, and goes on to state that ‘it was generally assumed that the European biodiversity had been entirely picked over by the natural history pioneers of the 19th century’. Well, ok, something can be a ‘widely held belief’ and still be pretty much untrue, but while one might expect that Europe is a well known place where few new species are found nowadays, these statements – like most media statements pertaining to the rarity of recently discovered species – are wildly inaccurate. Sure, there aren’t as many new mammals coming out of 21st century Europe as there are frogs coming out of Sri Lanka or whatever, but the fact remains that Europe – the most well-explored and intensively studied continent of them all – most certainly has produced new mammal species within the last 100 years, including within recent decades. What’s more, it hasn’t produced one or two new species, but 32 of them! Sorry Mus cypriacus, but you ain’t that special.

You will know from previous blog posts that during the last few decades a large number of tropical rodents have been named and described (see New, obscure, and nearly extinct rodents of South America and Giant furry pets of the Incas). And so it is with Europe, and among rodents we start with mice. Remember here that we’re only interested in those species that have been named over the past 100 years.

Five European mice have been named within the last 100 years, four of which are obscure, and one of which is well known and well studied. Firstly, we have the Cretan spiny mouse Acomys minous Bate, 1906, a cold-adapted island endemic (Bate’s publication is sometimes given as 1905, in which case this isn’t a ‘100 year’ mammal). The second species, the Western house mouse Mus domesticus Schwartz & Schwartz, 1943, is anything but poorly known, and though not recognized as distinct from M. musculus Linnaeus, 1758 until 1943, it can hardly be regarded as a recently discovered species. As the common name suggests, the Western house mouse is the house mouse species of western Europe (as well as northern Africa). It is replaced in Scandinavia and eastern Europe by M. musculus, and around the Mediterranean coast it is sympatric with the Algerian mouse M. spretus.

The third ‘100 year’ European mouse species was first described from Allgäu in Germany: it’s the Alpine wood mouse Apodemus alpicola Heinrich, 1952, now known to occur in the Alps of Switzerland, Liechenstein, Austria and Italy as well as those of Germany. Though first named as a new species, it later became regarded as a high-altitude subspecies of the Yellow-necked mouse A. flavicollis. A 1989 study demonstrated that it should be recognised as a distinct species again. Also belonging to the genus Apodemus is the Mount Hermon field mouse A. iconicus Heptner, 1948. This species has a complex nomenclatural history that I wont cover in full here, but of special interest is that a new species named from Israel in 1989 (A. hermonensis Filippucci et al., 1989) is now thought to be a junior synonym of A. iconicus: there are also a few older names (Mus sylvaticus var. tauricus Pallas, 1811, M. s. tauricus Barrett-Hamilton, 1900 and M. s. witherbyi Thomas, 1902) that some mammalogists regard as senior synonyms of A. iconicus, and if this is correct then A. iconicus is not a 100 year mammal. Though best associated with Israel and Turkey, A. iconicus has recently been added to the definitive European list as its now known to occur on Rhodes and Bozcaada (Kryštufek & Mozetič Francky 2005). Finally among mice, there is the recently discovered and poorly known Balkan short-tailed mouse Mus macedonicus Petrov & Ruzic, 1983.

Exactly as obscure as some of these mice are various ‘100 year’ vole species. One of them is comparatively well known however, and indeed is the best known recently discovered European mammal: the Bavarian pine vole Microtus bavaricus Konig, 1962 of the Bavarian and Italian Alps. Ironically, the reason the species is ‘best known’ is because it was thought to have become extinct: there was an absence of sightings after its discovery, and in 1980 a hospital was constructed on the location where it formerly occurred. However, the species was rediscovered by Friederike Spitzenberger in 2004 at a location in Austria.

Four other Microtus voles have been named within the last 100 years. Cabrera’s vole Microtus cabrerae Thomas, 1906 is a poorly known, endangered Spanish species. Far better studied is the Sibling vole Microtus rossiaemeridionalis Ognev, 1924, a species that occurs from Finland southward to Greece, and also occurs in eastern Asia (see adjacent image). Between 30 and 70 years ago it was accidentally introduced to Svalbard, and in some years large numbers of the species occur there. Though originally named in the 1920s, the name M. rossiaemeridionalis was forgotten about in the following decades. The discovery in the late 1960s that a population originally assumed to be part of the Common vole M. arvalis actually merited distinction then led to the naming of the new species M. subarvalis Meyer et al. 1972, and it was this population that then proved to be the same thing as M. rossiaemeridionalis.

The third species, the Tatra pine vole Microtus tatricus Kratochvíl, 1952, was first described from Slovakia but is now known to occur in Poland, Rumania and Ukraine. Finally, the Balkan pine vole Microtus felteni Malec & Storch, 1963 is of special interest with regard to recently named European mammals in that it is endemic to the former Yugoslavian province of Macedonia, an area where there are a further two endemic mammals: the Balkan or Stankovic’s mole T. stankovici and the Balkan short-tailed mouse Mus macedonicus. Of the two, the former was only named in 1931 and the latter in 1983, so Macedonia has proved a ‘hot-spot’ for new European mammals.

Another ‘100 years’ vole is the highly distinctive Balkan snow vole or Martino’s snow vole Dinaromys bogdanovi (Martino, 1922), originally named as a species of Microtus but awarded its own genus in 1955. Occurring in Croatia, Bosnia and Herzegovina, it may also be present in Albania and Greece. Fossils show that it formerly occurred more widely in Europe. Finally among voles, there is the Southern water vole Arvicola sapidus Miller, 1908, an endangered species of France, Spain and Portugal.

Finally among rodents, we come to another obscure and poorly known species, Roach’s mouse-tailed dormouse Myomimus roachi (Bate, 1937). First described from Israel as a fossil, it was discovered in living form in Bulgaria in 1960 and in Turkey in 1991. Several other species of this genus are known, all from eastern Asia, all named during the 20th century [the adjacent image shows one of these, M. personatus of Turkmenistan, Uzbekistan and Iran].

Moving now to lipotyphlans, or insectivorans or whatever you want to call them, we find that several species have been named within the last 100 years. Europe’s shrew species belong to three genera, Sorex (the long-tailed or red-toothed shrews), Crocidura (the white-toothed shrews) and Neomys (the Old World water shrews), and what’s interesting it that the ‘100 year’ species belong to all three of these. The new Sorex species are the Spanish or Iberian shrew S. granarius Miller, 1910, the Taiga or Even-toothed shrew S. isodon Turov, 1924 and the Appenine shrew S. samniticus Altobello, 1926. Though first described as a subspecies of the Common shrew S. araneus, the Spanish shrew is strongly distinct genetically and in having a particularly unusual short skull. The Taiga shrew occurs from Norway to as far east as Siberia and Sakhalin Island; it is a large, drab species with a broad braincase and particularly narrow snout. Though named in the 1920s it was later regarded as a subspecies of the Dusky shrew S. sinalis, a Chinese species, until Hoffmann (1987) showed that it should have remained as a species. The Appenine shrew is endemic to Italy, and while formerly regarded by some as conspecific with the Common shrew, it is quite different, having a much shorter tail for example.

Moving now to white-toothed shrews, we find that four European species have been named since the 1950s. Shrews have proved very good at colonizing islands, and only within recent decades have mammalogists started to properly describe and differentiate the island endemic white-toothed shrews of the European islands. Crete has its own recently-named white-toothed shrew, the Cretan white-toothed shrew C. zimmermanni Wettstein, 1953, while Pantelleria Island off Italy is home to C. cossyrensis Contoli, 1989. The Pantelleria shrew is controversial, with various studies indicating that it is a subspecies of the Greater white-toothed shrew (C. russula).

During the 1980s two new white-toothed shrews were named from the Canary Islands: the Canary shrew C. canariensis Hutterer et al., 1987 of Fuerteventura, Lanzarote and Lobos, and the Osorio shrew Crocidura osorio Molina & Hutterer, 1989 of Gran Canaria. The only other extant endemic mammal of the Canary Islands, the bat Plecotus teneriffae, was named in 1907 as a subspecies and given species status in 1985, so the islands have proved an important place for the discovery of new European mammals. Incidentally, there were other endemic mammals on the Canary Islands until recently, but they are today extinct. While its discovery falls outside of the last 100 years, of interest is that Sicily’s endemic white-toothed shrew was only named in 1900: the Sicilian shrew C. sicula Miller, 1900.

Though it has since been demoted to subspecific status, it’s also worth noting that the white-toothed shrew of the Isles of Scilly, Crocidura suaveolens cassiteridum, was originally named as a distinct species (C. cassiteridum) in 1924 (Hinton 1924) [see adjacent image]. This shrew isn’t unique to the Isles of Scilly, as it also occurs on Jersey and Sark, and given that it belongs to a species otherwise restricted to southern Europe it is usually thought of as an introduction from the Mediterranean region. Presumably it made the crossing in fodder or bedding for domestic animals. Incidentally, the Hinton who named the Scilly shrew is Martin Alister Campbell Hinton (1883-1961), former Keeper of Zoology at London’s Natural History Museum, and perhaps best known nowadays as possible perpetrator of the Piltdown hoax.

Finally among shrews, there is the Neomys species Miller’s water shrew Neomys anomalus Cabrera, 1907, also known as the Mediterranean or Cabrera or Southern water shrew. In contrast to the better-known Neomys species, N. anomalus is less well adapted for life in water, with a less well-developed tail keel and fewer fringes on the borders of its hind feet, and it differs in the shape of its lower jaw, in penis morphology, and in other characters from the other European Neomys species.

Among ‘100 year’ European lipotyphlans, it’s not all just shrews. Three new European mole species have been named since 1906: the Levant mole Talpa levantis Thomas, 1906, the Iberian mole T. occidentalis Cabrera, 1907, and the Balkan or Stankovic’s mole T. stankovici Martino & Martino, 1931. A fourth species, the Roman mole T. romana Thomas, 1902 was named 104 years ago. While all of these taxa were originally named as distinct species, they later became sunk into the synonymy of other species (yet more examples of laissez-faire lumping: see The many babirusa species: laissez-faire lumping under fire again), only to be resurrected during the 1990s. The Levant mole, an animal known from Bulgaria, Greece, Turkey and the adjacent part of the Caucasus, was mostly regarded as a subspecies of the Mediterranean mole T. caeca, until a revision of 1993, and the Iberian mole was similarly widely regarded as a Mediterranean mole subspecies until 1993. Similarly, the Balkan mole was regarded during recent decades as a subspecies of the Roman mole T. romana.

Finally, we come to bats. While most European bat species were formally named in the 1800s and before, new taxa continue to be discovered, with several species named this century. Many people might immediately think of the two pipistrelle species dubbed informally the 45 and 55 kHz pipistrelles: in 1993 it was discovered that the ‘species’ Pipistrellus pipistrellus actually consisted of two distinct species, both of which differed in the echolocation frequencies of their calls, and which were later shown to differ in genetics, morphology and behaviour (Barlow et al. 1997, Davidson-Watts & Jones 2006). However, while the many differences between these two species have only recently been acknowledged, both were originally named during the 1700s and 1800s: the 45 kHz pipistrelle is P. pipistellus (Schreber, 1774) while the 55 kHz pipistrelle is P. pygmaeus Leach, 1825. Consequently, neither bat can be considered a ‘100 year’ discovery.

However, vesper bats have yielded several bona fide new European species within the last 100 years, though as we shall see a few of them are of controversial status. The most recently named of them are the two long-eared bats Plecotus microdontus Spitzenberger et al. 2002 from Austria and P. sardus Mucedda et al., 2002 from Sardinia, though P. microdontus has since been regarded by some as synonymous with the Brown long-eared bat P. auritus. Also recently named is the Alpine long-eared bat P. alpinus Kiefer & Veith, 2001, named for a specimen collected in France in 2001 (Kiefer & Veith 2001). Additional specimens are known from Greece, Liechtenstein, Austria, Croatia and Switzerland, so there is every indication that the species is widespread. The Croatian specimen was collected in 1972 and the specimen from Liechtenstein in 1961: a reminder that the actual ‘discovery’ date of a species often doesn’t match the time when it becomes technically named and/or described.

Yet another recently recognised species, P. macrobullaris Kuzjakin, 1965, was named for long-eared bats from Switzerland and Austria supposedly intermediate between the Brown long-eared bat and Grey long-eared bat P. austriacus, but shown by Spitzenberger et al. (2001) to be worthy of species status. P. macrobullaris is now known from Croatia and elsewhere. To confuse matters further, recent work (see Juste et al. 2004) indicates that both P. microdontus and P. alpinus are synonymous with P. macrobullaris [adjacent image shows a long-eared bat. And no, I have no idea what species it is].

Several new long-eared bat subspecies have also been named within the last few decades, and new data has caused some of them to be newly elevated to species level. Within P. auritus, the subspecies P. a. hispanicus (later reidentified as a subspecies of P. austriacus) was named in 1957, P. a. kolombatovici in 1980, and P. a. begognae in 1990. Genetic studies have shown that P. a. kolombatovici is distinct enough to be regarded as a full species (Mayer & von Helverson 2001, Spitzenberger et al. 2001), though the animal labelled as P. a. kolombatovici by Spitzenberger et al. (2001) later turned out to be P. alpinus. Another form first named as a subspecies of P. auritus, P. a. teneriffae Barret-Hamilton, 1907, was recognised as worthy of species status in 1985. Though they started their taxonomic histories as subspecies, both P. kolombatovici and P. teneriffae can therefore be stated to have been discovered within the last 100 years.

Another new vesper bat, this time a mouse-eared bat, is in the ‘100 years’ club, but it seems unlikely to be a valid species. It’s the Nathaline bat Myotis nathalinae Tupinier, 1977, described for two specimens from Ciudad Real in Spain. However, it’s highly similar genetically and morphologically to Daubenton’s bat M. daubentonii (Tupinier 1977). Indeed Bogdanowicz (1990) found that the skull morphology of M. nathalinae fell within the range of variation exhibited by M. daubentonii populations, and therefore argued against the idea that it should be regarded as a valid species, while genetic samples of M. nathalinae have also fallen within the range of variation exhibited by M. daubentonii (Mayer & von Helverson 2001). Other studies have produced the same result, so bat workers generally regard M. nathalinae as a subspecies of M. daubentonii.

A second new mouse-eared bat, M. alcathoe von Helverson et al., 2001, is morphologically and genetically distinct, and noteworthy in being Europe’s smallest mouse-eared bat, and the one with the most high-pitched echolocation calls. First reported from Greece and Hungary, in 2003 it was reported from Slovakia.

So, so far it’s all been rodents, insectivores and bats: exactly those groups of mammals you’d expect to contain recently-discovered species. Indeed, that is about it. There is, however, a ‘100 year’ European lagomorph: the Broom hare Lepus castroviejoi Palacios, 1977 of the Catabrian Mountains of north-west Spain, a species regarded as merely a population of the European hare L. europaeus until 1976 (Palacios 1977). This poorly known hare is obscure and has been widely overlooked, in fact it’s missing from several (post-1977!) field guides on European mammals. There does appear to be widespread acceptance of its specific status, however, even though there is some indication that the species hybridizes with the Mountain hare L. timidus (Melo-Ferreira et al. 2005).

It’s pretty clear then that the Cypriot mouse is most certainly not ‘the first new mammal species to be found in Europe in over a century’, and I’m amazed that such a claim has been made. Despite the message that journalists write into their stories all the time, the discovery of new species is a routine thing, not an extraordinary one, and that goes even for mammals, and even for Europe. Don’t get me wrong: the Cypriot mouse is still a very interesting and significant discovery, but it is clearly not the major scientific event that has been implied by some.

To conclude, those European mammals named within the past 100 years – excluding the Cypriot mouse – are as follows. I might have missed some, in which case please let me know [UPDATE: list ammended as of 18-11-2006. Thanks to those who have provided new data]. As noted, a few species are of dubious status, and have been marked with **.

  1. Cretan spiny mouse Acomys minous Bate, 1906
  2. Western house mouse Mus domesticus Schwartz & Schwartz, 1943
  3. Alpine wood mouse Apodemus alpicola Heinrich, 1952
  4. Mount Hermon field mouse A. iconicus Heptner, 1948
  5. Balkan short-tailed mouse Mus macedonicus Petrov & Ruzic, 1983
  6. Bavarian pine vole Microtus bavaricus Konig, 1962
  7. Cabrera’s vole M. cabrerae Thomas, 1906
  8. Sibling vole M. rossiaemeridionalis Ognev, 1924
  9. Tatra pine vole M. tatricus Kratochvíl, 1952
  10. Balkan pine vole M. felteni Malec & Storch, 1963
  11. Balkan snow vole or Martino’s snow vole Dinaromys bogdanovi (Martino, 1922)
  12. Southern water vole Arvicola sapidus Miller, 1908
  13. Roach’s mouse-tailed dormouse Myomimus roachi (Bate, 1937)
  14. Spanish or Iberian shrew Sorex granarius Miller, 1910
  15. Taiga or Even-toothed shrew S. isodon Turov, 1924
  16. Appenine shrew S. samniticus Altobello, 1926
  17. Cretan white-toothed shrew Crocidura zimmermanni Wettstein, 1953
  18. Pantelleria Island shrew C. cossyrensis Contoli, 1989 **
  19. Canary shrew C. canariensis Hutterer et al., 1987
  20. Osorio shrew C. osorio Molina & Hutterer, 1989
  21. Miller’s water shrew Neomys anomalus Cabrera, 1907
  22. Levant mole Talpa levantis Thomas, 1906
  23. Iberian mole T. occidentalis Cabrera, 1907
  24. Balkan or Stankovic’s mole T. stankovici Martino & Martino, 1931
  25. Alpine long-eared bat Plecotus alpinus Kiefer & Veith, 2001 **
  26. P. microdontus Spitzenberger et al. 2002 **
  27. P. kolombatovici (Dulic, 1980)
  28. P. teneriffae Barret-Hamilton, 1907
  29. P. macrobullaris Kuzjakin, 1965
  30. Nathaline bat Myotis nathalinae Tupinier, 1977 **
  31. M. alcathoe von Helverson et al., 2001
  32. Broom hare Lepus castroviejoi Palacios, 1977
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Refs - -

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Bogdanowicz, W. 1990. Geographic variation and taxonomy of Daubenton’s bat, Myotis daubentoni, in Europe. Journal of Mammalogy 71, 205-218.

Davidson-Watts, I. & Jones, G. 2005. Differences in foraging behaviour between Pipistrellus pipistrellus (Schreber, 1774) and Pipistrellus pygmaeus (Leach, 1825). Journal of Zoology 268, 55-62.

Hinton, M. A. C. 1924. On a new species of Crocidura from Scilly. Annals and Magazine of Natural History 14, 509-510.

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Melo-Ferreira, J., Boursot, P., Suchentrunk, F., Ferrand, N. & Alves, P. C. 2005. Invasion from the cold past: extensive introgression of mountain hare (Lepus timidus) mitochondrial DNA into three other hare species in northern Iberia. Molecular Ecology 14, 24-59.

Palacios, F. 1977. Descripcion de una nueva especie de liebre (Lepus castroviejoi) endémica de la cordillera Cantabrica. Doñana Acta Vertebrata 3, 205-223.

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