Journal archives for August 2023

August 01, 2023

Incidence of alkaloids and cyanogenesis in plants in southwestern Western Australia

@charles_stirton @tonyrebelo @jeremygilmore @troos @graham_g @mr_fab @margl @russellbarrett @kelnat @ladyrobyn @russellcumming @eremophila @botaneek @alan_dandie @scottwgavins @jayhorn @kelsey414

The following Post is based on analyses conducted by the late Bill Foulds, author of and and


Western Australia is nutrient-poor. The indigenous plants are accordingly adapted, by tending to have evergreen, nutrient-poor foliage.

These plants defend themselves from herbivory/folivory mainly by means of fibrousness (sclerophylly) and tannins (which, like fibre, contain only carbon, hydrogen, and oxygen,, rather than by defensive compounds that contain nutrient elements.

However, the flora contains many plants that supplement their supplies of nitrogen, by means of microbial nitrogen-fixation, hemi-parasitism, or 'carnivory'.

This suggests that these plants might tend to contain defensive substances based on amino acids (which contain nitrogen) and cyanide (the molecular formula of which is HCN, viz. a combination of equal parts of hydrogen, carbon, and nitrogen).


The following is information on the incidence of alkaloid-containing and cyanogenic plants (including non-indigenous spp.) in southwestern Western Australia, in relation to the nutrient status of soils. (In the case of Styphelia and Cakile, the analysed values range from negative to strongly positive.)

The strongly alkaloid genera were

The strongly cyanogenic genera were

In the case of legumes other than Acacia, Lotus ( and Trifolium ( were found to be cyanogenic, and the former also contained alkaloids.

However, cyanogenic spp. also occurred in

A wide variety of plants on coastal dunes was cyanogenic. This included Banksia woodland on the Swan Coastal Plain (

The flora on sand dunes at Hillarys (,_Western_Australia) was notably rich (27% of spp. sampled) in alkaloid-containing plants. including a succulent introduced from South Africa, viz. Tetragonia decumbens ( However, Exocarpos in this environment lacked alkaloids.

No alkaloid-containing plants were recorded in woodland (sampled at Hepburn Heights, of Banksia ( and Eucalyptus gomphocephala ( on coastal sand.

In each plant community sampled near Perth (,of%20Serpentine%2DJarrahdale%20to%20the), only one species (of the hemi-parasitic genus Cassytha, was found to contain alkaloids.

In the case of the hemi-parasitic genus Cassytha,

Woodland of Eucalyptus salmonophloia (, under a semi-arid climate (, was particularly rich in hemi-parasitic plants (particularly as sampled near Yellowdine,,_Western_Australia).

The hemi-parasite Exocarpos ( contained alkaloids, but mistletoes did not. The mistletoes referred to are

The incidence of cyanogenetic plants in this woodland was less than in Banksia woodland under a mesic climate.


Many Acacia spp. are known to be cyanogenic.

The overall pattern seems to be that

  • toxicity in the form of alkaloids is fairly weakly expressed in southwestern Australia, and
  • in the same region, cyanogenic plants occur in environments with relatively mild, mesic climates and nutrient-rich soils.

There seems to be a lack of cyanogenic plants in mediterranean-type climates in which frost occurs. There may also be a lack under arid climates, but the pattern is unclear.

Why do grasses feature cyanogenesis but not alkaloids?


I am grateful to the late Bill Foulds for sharing his data with me, and for discussing the patterns.


The following refers to concentrations of phosphorus (parts per million) in topsoils.

  • 1-3 ppm P: broombush, mallee woodland, kwongan, banksia woodland, and jarrah forest
  • 4-8 ppm P: salmon gum woodland, granite outcrop, wandoo forest, limestone heathland, sand dunes
  • 26 ppm P: salina, ironstone outcrop


The following numbers of spp. were analysed for cyanogenesis in the various plant communities:

Semi-arid climate adjacent to mediterranean-type climate:

  • Broombush 25, mallee woodland 11, salina 23, kwongan 7, salmon gum woodland 17, granite outcrop 5, ironstone outcrop 7

Dry form of mediterranean-type climate:

  • Kwongan 28

Mesic form of mediterranean-type climate:

  • Banksia woodland 24, limestone heathland 42, sand dunes 19

Incidence of cyanogenic spp.:

Zero in all cases, except for banksia woodland (8.3% of analysed spp.) and sand dunes (31.6% of analysed spp.)


In each case, the first value is the no. of spp. analysed, and the second is the percentage of these found to contain alkaloids.

Semi-arid climate adjacent to mediterranean-type climate:

  • Broombush 36, of which 5.6%
  • Mallee woodland 23, of which 17.4%
  • Salina 43, of which 20.9%
  • Kwongan 21, of which 23.8%
  • Salmon gum woodland 30, of which 40%
  • Granite outcrop 26, of which 42.3%
  • Ironstone outcrop 4, of which 50%

Dry form of mediterranean-type climate:

  • Kwongan 90, of which 13.3%

Mesic form of mediterranean-type climate:

  • Banksia woodland 19, of which 0%
  • Jarrah forest 41, of which 2.4%
  • Granite outcrop 35, of which 2.8%
  • Wandoo forest 31, of which 6.4%
  • Limestone heathland 42, of which 7.1%
  • Sand dunes 12, of which 8.3%
Posted on August 01, 2023 09:04 PM by milewski milewski | 4 comments | Leave a comment

August 02, 2023

The frilled lizard (Agamidae: Chlamydosaurus kingii), part 1: an Australian genus, doubly odd beyond its cervical bluffing


Please see: and and and

Chlamydosaurus kingii ( and and is a distinctively Australian lizard.

This monospecific genus is well-known for an extreme anatomical structure: a foldable neck-frill, which is erectile by virtue of the opening of the mouth.

However, what is underappreciated is how odd this lizard is, in combining

  • specialisation for both arboreal (quadrupedal) locomotion and terrestrial (bipedal) locomotion, and
  • camouflage-colouration (when in trees, e.g. and warning colouration (when displaying to potential predators).


Chlamydosaurus kingii is specialised for clinging inconspicuously to the boles of trees (
and - which many photographs show it doing in the rainy season, as part of its sit-and-wait foraging strategy.

Furthermore, it spends the dry season on branches in the crowns of trees, where - in a metabolically quiescent state - it is further hidden by shading and plant-structural clutter.

What this means is that, for about half the year, the head is habitually oriented horizontally, while for the other half of the year, the head is habitually oriented vertically. During the former period, the animal tends to be semi-torpid and relatively inattentive, whereas in the latter period, the animal is alert, spotting its prey (mainly invertebrates) on the ground.

This implies that the eyes have a different relationship to the head during the two periods.

When C. kingii clings to boles, the rigidly vertical orientation of the head seems unremarkable.

However, this vertical orientation of the head tends to remain even when the animal stands quadrupedally on the ground ( and and and and - which it does mainly in the rainy season, when foraging on the ground.

The orientation tends towards the horizontal when C. kingii runs bipedally with the mouth open ( and and

What does not seem to have been pointed out before is that the eyelids - as well as presumably the eyeballs - swivel with changes in the orientation of the head, from vertical to horizontal.

Various animals, including caprin bovids ( and and, are capable of swivelling the eyeballs within the eye-sockets, compensating for shifts in orientation from horizontal to vertical.

Such swivelling of the eyeball itself is not apparent in photographs of C. kingii, because the pupil is circular.

However, photos do show that the eyelids swivel ( and and and and and and and and and and

This has not been recorded in any mammal or bird, and it suggests that the whole complex, of eyeball plus lids, swivels in the orbits

Turning now to gaits:

Despite its arboreal specialisation, C. kingii tends to adopt upright bipedality when running ( and and and walking on the ground.

Several Australian agamids tend to run bipedally. However,

  • none of these - apart from C. kingii - is arboreal, and
  • C. kingii is unique among agamids in being able to walk bipedally.

The upright bipedality of C. kingii seems to be facilitated by the proportionately long neck of the species, which allows the animal to lean backwards in maintaining balance.

What this means is that, in their own ways, both the eyes and the cervical vertebrae are adaptively modified in ways consistent with the dual locomotory specialisation of the species.


The conspicuous colouration of C. kingii is displayed while bluffing would-be predators, as well as when interacting socially/sexually (

The full anti-predator display - which is largely bluff, because the C. kingii has neither formidable teeth nor venom - consists of

  • erection of the frill,
  • opening of the mouth,
  • lashing of the tail, and
  • approaching and even contacting the human figure.

The colouration of C. kingii varies

  • ontogenetically (with infants having consistent camouflage-colouration, whether perched or among leaf-litter on the ground),
  • according to substrate (somewhat analogous with chameleons),
  • according to mood/season, and
  • geographically, with the frill tending to be red in the west, yellow in the east (with orange in the intermediate area), and whitish in the southeast (see photos at the end of this Post).

There seems to be scant sexual dimorphism in colouration in C. kingii, despite the fact that mature males can weigh twice as much as adult females, and have the head and frill disproportionately large.

If this is true, it is at odds with the family Agamidae, in which many or most spp. have males considerably brighter-hued than females.

Many photographs show pale jowls, contrasting with darkened ground-colour:

I have yet to understand the adaptive value of this feature, which

  • plays a negligible part in the display of the erect frill, and
  • is ambivalent w.r.t. functioning conspicuously (e.g. for communication intraspecifically among individuals with the frill folded) or inconspicuously (by disrupting the figure, in resemblance of a dapple of sunshine).


red hue (Kimberley of Western Australia):

yellow hue (northernmost Queensland):

dark spot on frill:

maximum display:

to be continued in

Posted on August 02, 2023 10:26 PM by milewski milewski | 18 comments | Leave a comment

August 04, 2023

August 09, 2023

The tallest vs the shortest vegetation on Earth

(writing in progress)


Forest of Eucalyptus regnans
Vegetation height possibly 110 m
Foliage intensely flammable
Regeneration involves episodic resetting to zero height, via crown-consuming, explosive wildfire
(lifespan of dominant species about one century, with longevity only ?400 years)


Forest of Sequoia sempervirens
Northern California
Vegetation height ?90 m
Foliage flammability ?
No resetting to zero? (lifespan of dominant species ?years, longevity about 2,000 years),sunlight%20can%20reach%20young%20seedlings.


Woodland of Sequoiadendrum giganteum
Vegetation height ?75 m
Foliage flammability?
No resetting to zero



Short grassland of Sporobolus kentrophyllus ( and and and Kyllinga nervosa (
Serengeti Plain
Vegetation height < 0.5 m
Fire permanently absent
Regeneration involves no temporal variation in height other than the reproductive heads of the graminoids


Posted on August 09, 2023 03:25 PM by milewski milewski | 11 comments | Leave a comment

August 10, 2023

True anteaters, in the strictest sense, are both few and extremely aberrant

(writing in progress)

Everyone knows that various animals are 'anteaters', viz. specialised for a diet of ants (Hymenoptera: Formicidae, These include mammals both placental and metatherian, birds (e.g. terrestrial woodpeckers), snakes (e.g. Typhlopidae), and various invertebrates (e.g. mygalomorph spiders), including certain species of ants themselves, predating other ants.

However, the loose use of the term 'anteater' hides a noteworthy biological pattern and principle.

This is that

  • extremely few animals actually eat the imagos of ants as their main diets, and
  • those that do are extremely aberrant in body-form and function, possibly owing to the energy-poverty of this food.

The confusion/obfuscation has arisen at several levels.

Firstly, 'anteaters' usually eat termites - which are completely unrelated to ants because the belong to the order Isoptera, not Hymenoptera - as well as ants.

Although termites, like ants, constitute energy-poor food, they allow a dietary diversification that hypothetically makes all the difference for the survival of 'anteaters'.

So, we can narrow our search-image to those animals in which the diet consists mainly of ants in the narrow/strict sense, viz. Formicidae.

Secondly, even 'true anteaters' usually rely on the eggs, larvae, and/or alates ( of ants, rather than just the imagos ( These 'reproductives' tend to be relatively rich as food for animals predating ants, because they tend to be relatively rich in lipid (, and relatively free of fibre (chitin, and toxins.

Thus, what is not generally appreciated is that

  • specialised ant-eaters have aberrant (peculiar/odd, body-forms and ways of life, and
  • this aberrational pattern can logically be related to the energetic and biochemical limitations that are peculiar to ants as food for insect-eating animals.

The basic idea is that

Among birds, the only true anteaters are

Posted on August 10, 2023 02:28 AM by milewski milewski | 2 comments | Leave a comment

August 11, 2023

Megaherbivores of the late Pleistocene in the proto-pampas of Buenos Aires province, Argentina

Also see and

In the late Pleistocene (, the following megaherbivores (with body mass exceeding one tonne) occurred in the general vicinity of what is now the port city, Buenos Aires (

My reference is Cione et al., 2003 (

This fossil fauna is, in palaeontological terms, called the Lujanian fauna (,and%20the%20armadillo%2Dlike%20Pachyarmatherium. and and and

At that time, sea level was lower than it is today, exposing a wide coastal shelf (

Therefore, the coast was far to the east.

This suggests that

  • the climate was drier than it is today, and
  • the vegetation was savanna, not treeless grassland.

It was this megafauna that Homo sapiens encountered, when our species first arrived, about ?13,000 years ago ( and and and

Of the taxa of megaherbivores listed and illustrated below, now extinct ( are










The richest fauna of megaherbivores in modern times is that of Africa, where five genera remain sympatric ( and and

These are

By comparison, the megaherbivores of the Lujanian fauna were surprisingly diverse, constituting

  • six orders instead of three (with Proboscidea and Artiodactyla occurring in both cases), and
  • 15 genera instead of five.

The single greatest difference is in the xenarthran ( orders Pilosa and Cingulata, containing ground sloths and glyptodonts. The ground sloths varied from mainly browsing (Megatheriidae) to mainly grazing (Mylodontidae).

These xenarthran forms, with what was presumably an extremely slow pace of life (metabolism, reproduction, and growth,, have no counterparts in modern faunas of savannas and grasslands.

In the Holocene fauna of South and central America, no megaherbivores whatsoever remain.

The order Artiodactyla was the only one of the Lujanian orders of megaherbivores remaining as an extant herbivore at the time of European arrival in 1516, where Buenos Aires now stands.

And even in this case, the form involved (Ozotoceros bezoarticus celer, and has a body mass of only 30 kg - which is a mere 3% of the one-tonne criterion for megaherbivores.

This extreme and abrupt loss of large animals, from what is now the pampas of Buenos Aires province (, remains a great puzzle of Biology.

Posted on August 11, 2023 10:19 AM by milewski milewski | 15 comments | Leave a comment

August 14, 2023

Predator-prey relationship between the largest sabre-tooth felid (Smilodon populator) and the largest litoptern meridiungulate (Macrauchenia patachonica), in South America in the late Pleistocene

@tonyrebelo @jeremygilmore @paradoxornithidae @diegoeseolivera @andrespautasso @marshall20 @matthewinabinett

Also see

Felids ( evolved in the Old World.

Meridiungulates ( evolved in South America when this continent was still isolated, unconnected to North America (

When a land-bridge arose from North America to South America, about 2.7 million years ago (, felids met meridiungulates - and began to prey on them.

By the late Pleistocene, both the sabre-tooth felid Smilodon ( and the litoptern genus Macrauchenia ( had undergone gigantism in South America. This resulted in

Two decades ago, this is how the BBC ( reconstructed the scene:,vid:sap-lHLrMC0 and,vid:jLyMwPinGFE

Adults of Macrauchenia patachonica ( weighed about 1100 kg - similar to the extant rhinoceros Diceros bicornis (

Macrauchenia patachonica also resembled rhinos in retaining three toes on each foot.

However, M. patachonica was unlike any ungulate (

It combined the following:

Together, these oddities suggest that M. patachonica

Farina et al. (2005, and have suggested that the sideways evasive action was one of 'swerving', when chased by S. populator.

This seems reasonable enough, in as far as it goes.

However, what Farina et al. (2005) may possibly have missed is the following addition to the rationale.

It seems to be uncontroversial that

Based on this 'concensus view', plus an assumption that S. populator hunted alone, my original thought is as follows.

Crucial to evasion of this particular specialised predator would have been an ability not only to swerve, but more particularly to 'buck sideways', in order to shake the body of the felid off the body of M. patachonica.

Such dislodging of the predator would allow the prey animal to resume acceleration in an attempt to outdistance the pouncer.

Sideways bucking in M. patachonica would help to explain the odd configuration of the bones - particularly the upper limbs but also the feet (retention of three toes) and the neck (carried horizontally).

Extant ungulates buck mainly vertically, as best-illustrated in rodeos ( and and

However, this has limited effectiveness against e.g. Panthera leo, because the felid can latch on with the teeth as well as the claws, and up-and-down movement is difficult when the body mass of the predator exceeds a quarter of that of the prey.

Bucking sideways would tend to use the body mass of the felid against it, with only the traction of the claws to overcome.

Certain ungulates possess dermal shields ( and Equus quagga is an extant example, with reinforced hide on the haunches (please see comment below).

If M. patachonica possessed a dorsal dermal shield in addition to the adaptations mentioned above, then this would limit the traction of the claws in the first place.

However, this is probably unknowable, given that all litopterns ( have been extinct for thousands of years, leaving us with only bones, not skin.

Posted on August 14, 2023 11:00 AM by milewski milewski | 10 comments | Leave a comment

August 20, 2023

Does bimodally seasonal rainfall promote species-diversity in large mammals, worldwide?

@paradoxornithidae @tonyrebelo @jeremygilmore

Everyone knows of the diversity of large mammals in Kenya (

However, how many naturalists understand the ecological reasons for this diversity?

One of the environmental factors distinguishing Kenya is that, in parts of this country, there are two rainy seasons each year (

This bimodality extends from Kenya to southern Uganda ( and northernmost Tanzania, as well as broadly to the Horn of Africa (

Bimodally seasonal rainfall is likely to boost the reliability of food through the annual cycle, for the indigenous ungulates.

In turn, this reliability hypothetically means that forms can specialise on particular foods, producing narrow niches, and allowing various closely-related species to coexist to a degree that might be impossible otherwise.

The result, if this principle is valid, would be faunas and communities of large mammals that - other factors being equal - are richer in species than those in climates with unimodally seasonal rainfall.

There at least 44 spp. of ungulates indigenous to Kenya (

The gerenuk (Litocranius walleri, seems to epitomise adaptation to bimodal seasonal rainfall.

This species of gazelle, occurring in Kenya and adjacent countries, is possibly the most specialised ungulate on Earth. It relies on the shoots of spinescent acacias, and has an accordingly aberrant body-form and posture.

Once one realises that Kenya has an unusual climate w.r.t. bimodally seasonal rainfall, a search-image arises for other regions on Earth that also show - albeit to a lesser degree - a similar correlation between climate and fauna.

Please see

This global map shows the regions as

  • reddish for rainfall regimes that have bimodally seasonal rainfall, and
  • whitish for adjacent regimes with some degree of bimodality, transitional to unimodally seasonal rainfall.

The more strongly unimodal the rainfall, the more intensely blue the portrayal is, in this map. For example, most of south-central and West Africa, plus the Sahel (, has rainfall simply concentrated in summer (e.g.

The effects of bimodally seasonal rainfall on the reliability of food for large mammals are likely to be outweighed/irrelevant where the climate is

  • arid (e.g. see the areas marked reddish in Egypt, and near Mecca in Saudi Arabia),
  • frigid (e.g. Greenland), or
  • pluvial (e.g. Congo/Cameroon/Gabon, northwestern Colombia, southern British Columbia, and northern Kalimantan on the island of Borneo).

Therefore, let us focus on those regions with mesic rainfall (250-1000 mm mean annual precipitation) and moderate temperatures.

The following regions, featuring reddish on the map, are noteworthy:

Of the regions mentioned above, the ones that I find climatically most surprising are those in Pakistan and Spain.

I have yet to understand how bimodality has arisen here, and I have yet to assess the indigenous fauna, given that these regions have long been intensely affected by human activity.

However, I can comment on the treeless grassland biome, found on all vegetated continents.

This biome is extremely inconsistent in the incidence and diversity of large mammals, as follows:

In the Highveld ( of South Africa, as many as 18 species of ungulates occur sympatrically (please see Table 1 in

This contrasts with South America: in the pampas of Buenos Aires province of Argentina, only two species occur.

North America and Eurasia have intermediate numbers.

Finally, in Australia - where there are no indigenous ungulates - macropod marsupials ( occur, but surprisingly few species penetrate the biome in question (

Is this variation explained by the seasonal distribution of rainfall?

The answer is obviously 'no'.

This is because the various regions of treeless grassland vary greatly in the seasonal distribution of rainfall, but with no apparent correlation with the fauna.

The region of treeless grassland in Eurasia has rainfall that is somewhat bimodally seasonal, which differs from North America. Both have similarly modest diversities of ungulates, with the caveat that in Eurasia the original fauna of the Holocene is not fully known. after thousands of years of human influence.
The puzzle is that the region of maximal diversity, viz. the Highveld, has unimodally seasonal rainfall ( By contrast, that of minimal diversity, viz. the pampas, has rainfall that is not strongly unimodal (

Turning now to biomes other than treeless grassland:

None of the other regions (Sri Lanka, Arizona, Spain, Pakistan) has a particularly diverse fauna of large mammals.

In the case of Sri Lanka, the situation is complicated by the fact that this has been an island since the start of the Holocene. Insularity can be expected to limit diversity.

The southernmost part of the Indian subcontinent, just north of Sri Lanka, has a tendency towards bimodally seasonal rainfall (

This region does have a diverse fauna of large mammals by Asian standards. For example, the indigenous artiodactyls of the Holocene are Sus scrofa (, Axis axis (, Rusa unicolor (, Muntiacus vaginalis (, Nilgiritragus hylocrius (, Antilope cervicapra (, and Moschiola indica (, plus possibly the wild ancestor of Bubalus bubalis in former times.

However, this fauna is not significantly more diverse than that farther north in India, where rainfall is unimodally seasonal.

I conclude, overall, that the pattern observed in Africa does not - for whichever reasons - seem to apply to other continents.

Posted on August 20, 2023 12:30 AM by milewski milewski | 5 comments | Leave a comment

August 24, 2023

Why has no tetrapod re-evolved gills?

(writing in progress)

Various lineages of tetrapods, after extensive modification for terrestrial life, have evolved to re-enter the water (foraging entirely underwater).

These include

All of these forms have evolved streamlining and fin-like flippers. However, all retain lungs, and none has re-evolved gills.

Therefore, all aquatic tetrapods are limited by the need to return to the surface each time they inhale.

Why have gills not re-evolved?

Posted on August 24, 2023 05:35 AM by milewski milewski | 5 comments | Leave a comment

August 26, 2023