Friday, 30 May 2025

Crocodiles and Birds at the Mirador de las Aves near San Blas in Mexico


We have seen lots of crocodilians in the wild but rarely doing anything but sunning themselves or just lying in the water. When we pulled into a lay-by complete with food stalls and an iron-railinged viewing area on the outskirts of San Blas in Mexico to look at the birds on the lagoon and in the surrounding mangroves, I had read that American Crocodiles (Crocodylus acutus) could be seen there. The lay-by whose name gives a clue as to its avian delights, Mirador de las Aves, is clearly a popular place to stop, buy a snack and look at the wildlife as locals drive along the road on a Sunday evening.

And there were crocodiles, large ones hauled out just under the viewing platform and basking in the sun on the edge of the lagoon. However, as the sun went down and moved off the crocodiles they entered the water and several apparently began searching the bottom for food with one, as the video below shows, emerging to swallow something small it had caught or found. Eventually I counted seven moving around offshore or simply hanging in the water as dusk fell.





Wednesday, 28 May 2025

Animals of the Namib Desert. The South African Zoologist Who Worked Out How They Survive On the Foggy Foggy Dew


Last month we had a very brief visit, counted in minutes not hours, to Stellenbosch in South Africa. A few days later we were visiting Namibia for a couple of days and for a second time. The Namibian desert with its sand dunes is famous for the ways in which the various species of animals and plants that live there obtain water. The Namib is very different to what many think of as a desert because although it lacks rain it gets regular and small amounts of water delivered to it in the air.  In short it is a land of fog and dew. The sea off Namibia is cold by virtue of the Benguela current running north. Thus fog banks form along the coast which are blown into the western part of the Namib. Water vapour condenses on surfaces during the cool night and penetrates the soil during the hot day. We have all seen on television the ways in which some beetles channel condensed water collected on their bodies into their mouths.  Snakes lick condensed water collected on their scales. Dune lizards, which occur only in the fog belt of the Namib, by contrast, drink avidly from surfaces and sand but then store water in the expanded caecum for several months. The Hairy-footed Gerbil (Gerbillurus paeba), unlike some other desert rodents, cannot not survive on dried seed alone; it relies on water from the succulent plants that in turn rely on the fog and dew.


The only university building we had time to see in Stellenbosch
housed the Faculty of Theology

Namibia and Stellenbosch were connected in my mind because exactly 50 years ago we had a visiting worker in the department, the man who put the desert animals of Namibia on the map. Gideon Louw* spent January to June 1975 working on mammalian thermoregulation with John Bligh. Although the rest of the department did not see much of him, he did come along for a chat several times and we discussed all sorts of things about how all sorts of animals work in all sorts of environments. I remember the impression of a very nice man but deeply troubled by events in his own country. He was, I now learn, then shortly to move from his position as Professor of Zoology in Stellenbosch to the University of Cape Town. Biographers have recorded that Gideon Louw was a founder member of the Progressive Party which was utterly opposed to the apartheid policies being imposed by the government then in power. Stellenbosch was I have also learnt a  stronghold of support for the National Party and an uncomfortable place for those opposed to its policies.


Gideon Louw

In an appreciation of the work of Gideon Louw published in 2004, Joh Henschel and Mary Sealy wrote (references  omitted):

In hyperarid areas such as the Namib Desert the occurrence of fog and dew plays an important role in the water economy of many desert organisms. This fact was known, particularly through the works of Walter (1936) and Koch (1961), by the time that Louw first visited the Gobabeb Training & Research Centre in the Namib Desert in 1966.

Louw soon recognised that ecophysiological mechanisms were a key towards understanding the relationship between atmospheric moisture and desert organisms. Extensive contributions of this doyen of desert ecophysiology range from water, energy, and salt balance, to thermal biology, conjunctively in terms of physiology, behaviour and ecology. He inspired a generation of students and colleagues to elucidate these mechanisms and their consequences, and later reviewed some of these insights.

Like a number of others working in his field, Louw did not have a first or even a higher degree in zoology. He had started on the animal science of agriculture and his first job was as an agricultural geneticist. Several spells in the USA, including a PhD in endocrinology at Cornell, followed before he returned to South Africa and a personal chair in zoology at Stellenbosch.

Louw’s work in Namibia became well known internationally when he was invited by Geoffrey Maloiy, the organiser, to a Zoological Society of London Symposium ‘Comparative Physiology of Desert Animals’ in July 1971, a meeting I had to miss because of a clash of dates. The published volume is still worth reading since all the major players in the field were contributors and showed the state of play after a major burst of activity that followed World War II.

Gideon Louw did much more than his research on the animals and environment of the Namib including writing several books, while his students have spread across the world and are well-established names in the biological sciences. From the reading I have done it appears that he was appalled by the political violence sweeping South Africa in the early 1990s and retired to Canada. He died on Vancouver Island on 22 March 2004, aged 73.


SJP spotted this lizard in the dunes at the deserted mining village of Kolmanskop
near Luderitz in Namibia. It is the Common Rough-scaled Lizard(Meroles
squamulosa
) a psammophilous species closely related to the dune lizard
(M. anchietae) studied by Gideon Louw
(Noble Caledonia Expedition Team Photograph)

This beetle was on the dunes at Kolmanskop

Lichens on rocks in the desert get their water from the dew

The reason this lichen is so green is that there had been rain
sufficient for water from the Swakop River to empty into
the Atlantic as in 2011 and 2022

A wide-angle view from the 'moonscape' viewpoint inland from Swakopmund


*Gideon Nel Louw, born 24 December 1930 East London, South Africa; died 22 March 2004.

Anon. 2004. Tribute to world-renowned zoologist. University of Cape Town News HERE

Cherry M. 2005. Gideon Louw (1930-2004). South African Journal of Science 101, 399.

Henschel JR, Seely MK. 2004. First Approximation of the Ecophysiology of Fog and Dew – A Tribute to Gideon Louw. Proceedings of the Third International Conference on Fog, Fog Collection and Dew: Cape Town, South Africa, 11-15 October 2004 [no page numbers shown].

Louw GN. 1972. The role of advective fog in the water economy of certain Namib desert animals. Symposia of the Zoological Society of London 31, 297-314.


Thursday, 22 May 2025

Roseate Spoonbills Feeding in Mexico


 

Roseate Spoonbills (Platalea ajaja) were feeding in a roadside lagoon near San Blas on the Pacific Coast of Mexico in early February. Having seen all six species of spoonbill on our travels around the world these were by far the most active we had come across. The frantic sweeping of the bill left and right, the sudden snap shut and the lift to swallow whatever they have caught is an amazing spectacle. If you look closely at my video you will see one catches and swallows a small fish.

There have been all sorts of suggestions as to how spoonbills detect the prey passing between the upper and lower ‘spoons’ and thus rigger the bill to snap closed. There is a good discussion of the topic by Bruce Taggart HERE.

We passed this lagoon (with a restaurant by the edge) several times. Each time it had large numbers of Great (Great White) (Ardea alba) and Snowy Egrets (Egretta thula), as well as the spoonbills.


Tuesday, 20 May 2025

Do Not Annoy an Amphiuma

I came across a video on YouTube which reminded me of what happened 49 years ago and the tale that followed. In previous articles I have recounted the appearance of the now critically endangered giant salamanders of China in the zoology department of the University of Hong Kong for class dissection. We took some on to the roof to photograph them before they were killed ready for the students  One lunged with its mouth open and snapped at SJP’s hand which she withdrew rather rapidly thus avoiding a bite.

Back down in the lab we were told that John Phillips, the head of department, had been bitten badly by another amphibian, an amphiuma, and that he had, as a result, had a recurring fever which took a long time to go away.

I should say that I have never seen an amphiuma, alive or dead, but to anglers and commercial fishermen in the right part of the USA they are a familiar sight. Amphiumas are eel-like salamanders which can grow to over a  metre in length. They are virtually entirely aquatic, living in swamps, lakes and ponds, but will move on land after heavy rain. They are nocturnal and carnivorous.

What was John doing with amphiumas I asked myself, knowing that in the late 1950s or early 1960s it would be something to do with the hormones produced by the adrenal cortex. After a bit of searching I found a reference that provided some of the information. The results were reported as part of a paper given at a symposium on comparative endocrinology held at Cold Spring Harbor in  May 1958. John had arrived in the USA in September 1957 after working for his PhD in Liverpool. I cannot be certain whether his encounter with an amphiuma was in Liverpool or shortly after his arrival at Yale on Fellowship of the Commonwealth Fund of New York. I cannot get hold of the paper (published in 1959) but I suspect it did not give much further information on where the various studies were done. Since he is known to have continued his work on adrenocortical secretions in vertebrates at that time, my bet would be Yale. Furthermore, amphiumas were readily available in the USA from biological suppliers.

The amphiuma in question was a Three-toed Amphiuma (Amphiuma tridactylum) easily distinguished by the number of toes on its tiny legs. Its distribution is ‘centered on the lower Mississippi River from Texas to western Alabama, and north to southern Illinois and extreme southwestern Kentucky’. They were and probably still are a source for laboratory suppliers since they are a bycatch from crayfish trapping.


Three-toed Amphiuma
Photo by Ashley Wahlberg (Tubbs) via Flickr

All descriptions of amphiumas note that they bite savagely as well as being very difficult to handle because of the slimy mucus on the tough skin. It is no wonder amphiumas are called ‘eels’ as in ‘congo eels’, a term derived from conger eels. No wonder John Phillips got bitten and became infected by some pathogen lurking at the bottom of a swamp.

As the following video shows, it is not only when handling amphiumas that they are liable to bite.



Seventy years since John Phillips started his pioneering work there is still active research and discussion on why the adrenal glands of different groups and species of vertebrates produce either or both of the two steroid hormones, cortisol and corticosterone. Indeed, the field is just hotting up again.

*John Guest Phillips FRS.1933-1987.

Chester Jones I, Phillips JG, Holmes WN. 1959. Comparative physiology of the adrenal cortex. In Comparative Endocrinology: Proceedings of the Columbia University Symposium held at Cold Spring Harbor 1958. (ed. A. Gorbman), 582-612. New York: Wiley.

Sandor T. 1969. A comparative survey of steroids and steroidogenic pathways throughout the vertebrates. General and Comparative Endocrinology Supplement 2, 284-298.

Vinson GP, Tait JF. 1988. John Guest Phillips. 13 June 1933-14 March 1987. Biographical Memoirs  of Fellows of the Royal Society 34, 610-637 doi: 10.1098/rsbm.1988.0020


Tuesday, 13 May 2025

Identification of the Coelacanth in 1939. A fishy story or just a fishy story?

If the 1950s had a celebrity species, it was the Coelacanth. Mysterious and only recently discovered to be alive rather than existing as fossilised remains, there was massive media coverage of this ‘living fossil’. The second specimen was discovered in 1952 and the story was kept fresh by the publication of J.L.B. Smith’s book published in London as Old Fourlegs. The Story of the Coelacanth and in New York as The Search Beneath the Sea – The Story of the Coelacanth, in 1956.

Coverage of the story was all over the media and I remember late one night in the late 1950s staying at my grandmother cousin’s house in Hendon, north London, searching for something to read in her extensive bookshelves. I picked up a copy of Reader’s Digest and there was the intriguing title of an article, ‘The fish named L.C. Smith’.  The title was of course an abbreviation of the scientific name, Latimeria chalumnae Smith 1939.


Rhodes University

The central character of the coelacanth story is James Leonard Brierley Smith (1897–1968). He was an organic chemist, educated in South Africa. He then did research in Cambridge. He received the 14th Ph.D. degree to be awarded by that university in 1922 for a thesis entitled, Interaction of sulphur monochloride with substituted ethylenes. He was plagued by illness which began while serving in the army during the First World War; this continued after he had returned to South Africa and life as a lecturer in the chemistry department of the University of Grahamstown. An interest in sea fishing developed into research in ichthyology an arrangement that often did not meet with the approval of the university. He was, when it came to fish, a professional scientist and university lecturer but an amateur ichthyologist. By the late 1930s he had become though the acknowledged expert on the fishes of South Africa.

The basic story of the discovery of the first specimen is well known.  On 22 December 1938, Marjorie Courtenay-Latimer (1907– 2004), the enthusiastic curator of the East London Museum in Eastern Cape, answered a telephone call  from the skipper of a trawler asking if she would have a look at some interesting bycatch. One fish stood out: five-feet long, beautifully coloured with hard scales, limb-like fins and a distinctive tail. She did not know what it was. She and an assistant carried it in a taxi to the museum but after consulting her books still could not identify it. She then wrote to J.L.B. Smith at Rhodes University in Grahamstown including in her letter a drawing of the fish. But he was away and Miss Courtenay-Latimer grew increasingly desperate as the fish (refused entry into the local mortuary’s frig and the cold store) by now wrapped in formalin-soaked blankets in the premises of the town taxidermist was starting to go off. Eventually, and desperate to preserve something, she had the taxidermist skin and stuff the fish in the manner of a ‘game’ fish. Smith’s eventually received the letter while he was still away from Grahamstown in Knysna, 350 miles from East London. He immediately realised from the drawing that he was looking at something special when it dawned on him that it could be a coelacanth. Scales from the fish were sent to him which convinced him that it was indeed a coelacanth. When he and his wife were back in Grahamstown they travelled to East London to see the fish. It really was a coelacanth. And the world went coelacanth crazy as the news got out. The fish had been caught off the mouth of the Chalumna River. Smith therefore came up with the scientific name to mark the achievement of Marjorie Courtenay-Latimer in realising the fish was something special and doing everything she could to get it preserved and identified together its origin. One might have thought that commemorating the Captain of the trawler, Nerine, Handrik Goosen, might have been more appropriate since he could easily have chucked the by-catch coelacanth over the side; instead he consulted the local museum.


from Smith 1956

Key locations in the identification of the coelacanth
Having passed down this coast by ship last month I wonder how close
we came to a living coelacanth

from Smith 1956

The coelacanth from December 1938 as Smith saw it on reaching East London
from Smith 1956

But there is a twist. While looking for something else entirely I came across an excellent history of the entomology and zoology department of Rhodes University in Grahamstown (now Makhanda) and found this:

[J.C.] Van Hille always considered that Alice Lyle never received credit for her achievements. He also believed that she played a critical role in the identification of the first coelacanth (Latimeria chalumnae) in 1938. In a letter to Miles dated 30 April 1980 van Hille wrote: “The zoo lecturer you refer to was Alice Lyle, she was a dear! It was actually she who identified the coela canth. Miss Latimer, of the East London museum saw that it was something quaint and kept it in formalin in her bath. She sent a little sketch to J.L.B. [Smith] who was on holiday in Knysna and was slow in reacting. Eventually he took the sketch to Omer-Cooper {the head of department and an entomologist] who also had no idea. Alice came in to bring them tea and saw it and said ‘I have seen it before’. She studied in Bloemfontein [Grey University College which became the University College of the Orange Free State] where the emphasis was on vertebrates. Omer was more of an Entomologist and Smith a Chemist. So Alice got the Cambridge Natural History from the library and there was a good picture of the coelacanth. I [van Hille] have this story from Omer and always think of it when in all the books and articles it mentions that J.L.B identified the coelacanth.” Lyle resigned from Rhodes in 1949 for an appointment as Guide Lecturer at the Durban Museum, where she also lectured to 1st year medical students at Natal University. She was appointed to Fort Hare as Professor of Zoology in 1952 but sadly died in October of that year in Cape Town.


I have found no indication that it was Alice Lyle who identified the drawing as a coelacanth before Smith. His letters, reproduced in his book, show that he was virtually convinced it was a coelacanth before leaving Knysna and had written to Courtenay-Latimer to say so. It is tempting to speculate that Smith may have gone to the zoology department looking for illustrations of coelacanths and that Alice Lyle found one in the Cambridge Natural History Volume 7. However, that illustration is from Arthur Smith Woodward’s 1888 catalogue of fossil fishes in the Natural History Museum in London and we know from Smith’s book that he had already consulted that volume, having had it sent from Cape Town to Knysna when he realised the possibility that he may be dealing with a coelacanth. Indeed, he adapted the illustration from Smith Woodward for his 1956 book.


Illustration in the Cambridge Natural History

from Smith 1956

Smith’s visit to the zoology department must have been during the second week of February 1939. As shown in the quoted passage below, Smith had intended to drive straight from Knysna to East London. However, the roads were difficult because of heavy rain and he had to head for Grahamstown and stay there a week before reaching East London on 16 February.

We are left pondering. Is the story of Alice Lyle identifying the coelacanth, in fishy terms, a red herring (zoologically, a clupea rubra)? Was a conversation misheard in which Smith consulted colleagues to see if they agreed with his tentative identification? Beyond that sort of explanation we would be in the realms of conspiracy theory.

Finally, the passage from Smith’s book in which he saw at long last what became the most famous fish in the world:

We left Knysna on the 8th February 1939, intending to go straight through to East London, but there was to be nothing easy about this, for we travelled in continuous heavy rain and were fortunate to reach Grahamstown, since by that time floods had rendered almost all roads impassable. Drifts and slippery mud made motoring in South Africa no light undertaking in those days. We had to wait a whole week before the roads to East London became usable, and after an awful journey reached there on the16th February 1939.

We went straight to the Museum. Miss Latimer was out for the moment, the caretaker ushered us into the inner room and there was the—Coelacanth, yes, God! Although I had come prepared, that first sight hit me like a white-hot blast and made me feel shaky and queer, my body tingled. I stood as if stricken to stone. Yes, there was not a shadow of doubt, scale by scale, bone by bone, fin by fin, it was a true Coelacanth. It could have been one of those creatures of 200 million years ago come alive again. I forgot everything else and just looked and looked, and then almost fearfully went close up and touched and stroked, while my wife watched in silence. Miss Latimer came in and greeted us warmly. It was only then that speech came back, the exact words I have forgotten, but it was to tell them that it was true, it was really true, it was unquestionably a Coelacanth. Not even I could doubt any more.


Live coelacanth seen off Pumula on the KwaZulu-Natal South Coast, South Africa, 2019
Bruce A.S. Henderson, CC BY 4.0
<https://creativecommons.org/licenses/by/4.0>, via Wikimedia Commons

Go! & Express. 27 February 2020
The coin was minted in 1998


Bruton, MN, Coutouvidis SE, Pote J. 1991 Bibliography of the living coelacanth Latimeria chalumnae, with comments on publication trends. Environmental Biology of Fishes 32, 403-433.

Dugan J. 1955. The fished named  L.c. Smith. Reader’s Digest, December 1955, 147-151.

Hodgson AN, Craig AJFK. 2005. A century of zoology and entomology at Rhodes University, 1905 to 2005. Transactions of the Royal Society of South Africa 60, 1-18.

Smith JLB. 1956. Old Fourlegs. The Story of the Coelacanth. London: Longmans, Green and The Search Beneath the Sea. The Story of the Coelacanth. New York: Henry Holt.


Monday, 5 May 2025

Dr Lyon in 1916 questions: “Who the hell put the ‘l’ in Ambystoma” - or words to that effect

Spotted Salamander (Ambystoma maculatum) (32855631122)
Spotted Salamander, Ambystoma maculatum
Peter Paplanus from St. Louis, Missouri, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons

 

When I wrote the recently article on the Michoacán Stream Salamander (Ambystoma rivulare), I remembered that readers of old books and papers, like Hans Gadow’s volume Amphibia and Reptiles in the Cambridge  Natural History Series first published in 1901, will be puzzled by the spelling of the generic name of mole salamanders, Amblystoma, rather than the one used today, Ambystoma.

In the last decades of the 19th century and the early part of 20th, Amblystoma was in general use for these salamanders of Canada, USA and Mexico, together with derivations like ‘amblystome’ as a common name. So why is the accepted name now Ambystoma?

It was Marcus Ward Lyon (1875-1942), medical man and mammalogist, who asked that question—with a certain degree of indignance— in a letter to Science in 1916:



Two letters were published in reply. The first, very long  and rambling, was from the etymologist Charles Payson Gurley Scott (1853-1936). He was pretty well convinced that Tschudi and/or the printer had made a slip of the pen (the lapsus calami) or a consistent typo since Amblystoma simply meant ‘blunt mouth’ and ‘Ambly’ was used in similar circumstances for other animals, the lizard Amblyrhyncus, for example. ‘Amby’ however had no meaning in the ancient languages. The second letter merely noted that another American author had used ‘Ambystoma’ as the correct form in 1909.

Leonhard Hess Stejneger (1851– 1943) had argued strongly that Tschudi's name should be used:





The scientific names of animals can be changed if there is evidence of a spelling mistake, however caused, in the original publication. One example is that of the American Alligator, originally named with the specific name ‘mississipiensis’ by Daudin in 1802 but later corrected to ‘mississippiensis’. However in the case of Ambystoma there was no evidence that Tschudi had suffered a lapsus calami and so the name used by Louis Agassiz (who must have also thought that Johann Jakob von Tschudi (1818–1889) had simply made an error) was replaced by the original, a case with so much Latin and Greek in play, of nunc pro tunc. Ambystoma was thus restored.

When Agassiz prepared his Nomenclator Zoologicus, a list of all names used in zoological genera  in 1842-1846 he was based in Europe. Both he and Tschudi were Swiss and I cannot help wondering if there was correspondence between the two along the lines of. ‘I say old chap I was just wondering if your name Ambystoma was the correct spelling for the name you intended?’ And if not, why not?

For my pennyworth, I would question why Tschudi would erect a genus meaning blunt-nosed for a  group  when European salamanders with which he would be familiar, Salamandra salamandra, for example, also have a blunt nose. Having seen Axolotls and Spotted Salamanders feeding on large earthworms I can see why stuffing the mouth might seem appropriate.

The world had other things on its mind in 1916 and well-known books, like Gadow’s were reprinted into the 1920s (with reprints appearing as late as 1968). Thus it is no surprise that, Amblystoma continued to be used well into the 20th century. Indeed I was surprised to see Amblystoma used by Malcolm Smith in his New Naturalist Series book, The British Amphibians & Reptiles, published in 1951. Perhaps those at the Natural Museum in London agreed with Agassiz and carried on regardless. Or perhaps that was a lapsus calami.


Lyon MW. 1916. Ambystoma not Amblystoma. Science. 43, 929-930.

Scott CPG. 1916. Amblystoma not Ambystoma. Science. 44, 309-311.

Stejneger L. 1907. Herpetology of Japan and Adjacent Territory. Bulletin of the United States National Museum 58, 24.

Friday, 2 May 2025

An Endangered Salamander in Mexico: The Toluca Axolotl or Michoacán Stream Salamander

As if a morning in Mexico gazing at a wildlife spectacular—one of the sites where Monarch butterflies gather in their millions from all over North America east of the Rockies to overwinter—was not enough, a short distance away from the entrance to the Monarch Reserve at Sierra Chincua and at an altitude at just over 10,500 feet (3220 metres) was another gem. A slowly-moving shallow stream across a cow field has a population of the endangered Michoacan Stream Salamander, and a number were out and about and feeding while we were there at the end of January.

We could see the salamanders moving about on the bottom of the slightly cloudy stream and had I not picked up the wrong-sized polarising filter for the camera lens when packing I would have better photographs and video to show. We were able to see them feeding on small invertebrates in the water and of blowing water from their lips to stir up the sand and reveal hidden prey.


Ambystoma rivulare, the Michoacán Stream Salamander or Toluca Axolotl



These salamanders are said to be like their close relation the Axolotl (Ambystoma mexicanum) in being neotenic but also capable of metamorphosis and breeding as transformed adults.

The evolution and taxonomy of salamanders from the Trans-Mexican Volcanic Belt is complex. It does not help when two species are sometimes known by the same common name, as in this case. However, it is clear from distribution maps and publications from Mexico on the fauna of the Monarch reserve that the species here is the Michoacán Stream Salamander, Ambystoma rivulare, which in Mexico is also being called the Mountain Stream Salamander. The distribution of A. rivulare in fact straddles the state border between Michoacán and Mexico (the latter a state within the country of Mexico).


Range of Ambystoma rivulare (from IUCN Red List) with the site we visited shown by the red dot


Ambystoma rivulare seems to have acquired another common name amongst Mexican scientists. The authors of a number of research paper call it the Toluca Axolotl, Toluca being the nearest city (and capital of the State of Mexico) to the sites where it can be found.

Confusion can arise because another species is also known as the Michoacán Stream Salamander. Thus two species with that same common name are listed in the IUCN Red List. The other species is Ambystoma ordinarium. However, that one is found further west than A. rivulare according to the distribution maps in the IUCN Red List.

The population of A. rivulare is reckoned to have decreased in recent years, particularly since non-native trout have been introduced to the streams for anglers.

None of the distances between the distributions of Ambystoma species in the Volcanic Belt is very great. Thus the ranges of the Axolotl (Ambystoma mexicanum), A. rivulare and A. ordinarium all occur within 100 miles, illustrating the adaptive radiation that has occurred in this volcanic region of central Mexico, producing what seems to be more than 10 species, each confined to a relatively small area.

The term ‘mountain stream’ suggests to me fast-moving water tumbling over rocks, quite unlike the habitat of A. rivulare that we were in, a stream across a flat field at high altitude. The only way to describe it was that it reminded me of the stream in which we used to catch Common Newts in the lowlands of the East Midlands 70 years ago.


Google Earth view of the site. The stream enters the pasture from the pine forest (top left)


Along with the Monarchs and a good lunch we had what can only be described as a grand day out—tempered only by the dreadful dinner later.