A photo-guide to the bewilderingly complex colouration of the South African rock-dwelling agamid, Agama atra, part 1

@karooicus @botswanabugs @dinofelis @grant_reed_botswana @chris_whitehouse @joctober @bluehillescape @ryanvanhuyssteen @tom-kirschey @b_akeret @ivanparr @tonyrebelo @jeremygilmore @alexanderr @tyroneping @herping_with_berks @herping_with_sean @peter_erb @m_burger @asimakis_patitsas @max_tibby @grahamarmstrong @rfoster @snakesrcool @calebcam @colin25 @cthawley @agama-girl @johannesvanrooyen @ludwig_muller @karoopixie @alexdreyer @i_c_riddell @ptexis @cr_hundermark @dhfischer @wesselpretorius @richardgill @felix_riegel @vynbos @shauns @riana60

Please see https://www.inaturalist.org/posts/86639-male-and-female-phenotypes-of-the-southern-rock-agama#

https://www.hfsp.org/hfsp-news/how-lizards-change-their-colour#:~:text=Agama%20lizards%20in%20southern%20Africa,to%20how%20humans%20become%20tan.

The southern rock agama (Agama atra) presents an unusual opportunity - and a considerable challenge - for an illustrated Post.

This is because it combines

a profusion of observations in iNaturalist, and
bewildering variation in appearance, particularly colouration.

Chameleons (https://en.wikipedia.org/wiki/Chameleon) are the Iguania (https://en.wikipedia.org/wiki/Iguanomorpha) taken to epitomise the versatility of colouration in lizards. However, an argument can be made that the southern rock agama - belonging to the same suborder - is an equally good example of similar phenomena.

The southern rock agama can be

extremely camouflaged (https://www.inaturalist.org/observations/33317589 and https://www.inaturalist.org/observations/140880918 and https://www.inaturalist.org/observations/20960993 and https://www.inaturalist.org/observations/140848979),
extremely conspicuous (female: https://www.dreamstime.com/royalty-free-stock-photo-southern-rock-agama-image24239135 ; male: https://www.gettyimages.com.au/detail/photo/male-southern-rock-agama-sunning-itself-on-a-rock-royalty-free-image/98218799?phrase=southern+rock+agama&adppopup=true), or
various confusing intermediates.

More broadly, scrolling through the thousands of photos in iNaturalist gives a kaleidoscopic impression, rather than one of a single species.

AIMS

There is no particular problem identifying Agama atra, because it is the only rock-dwelling agamid over most of South Africa.

However, it is another matter to understand why this species has such an inconsistent appearance.

So, my aim in this Post is to tease apart various factors contributing to the confusing colouration of this lizard.

METHODS

I have carefully chosen illustrations from the innumerable available on the Web, in an attempt to disentangle the various factors in the colouration.

I restrict the coverage to

the dorsal and lateral surfaces of the figure (as opposed to the usually hidden ventral surface of the torso), and
hues visible to the human eye (as opposed to ultraviolet).

CONTRIBUTING FACTORS

There seem to be six main factors combining to determine the appearance of the southern rock agama, viz.

urgent thermoregulation,
growth and development from juvenile (https://www.inaturalist.org/observations/107643158) to adulthood and full (social) maturity,
sex,
individuality,
breeding condition, and
mood/emotion (possibly social/sexual excitement but certainly fear, when approached by a potential predator).

These six factors result, respectively, in the following approximate results:

conspicuous but temporary darkness vs pallor, presumably according to temperatures,
camouflage, particularly in juveniles (https://www.inaturalist.org/observations/141814898),
different patterns of colouration in females and males, in complex ways involving both hues and dark/pale contrast,
individual/sexual variation in disruptive mottling (camouflage-colouration, https://www.inaturalist.org/observations/149743803), pale vertebral striping, and hues (particularly on the hindquarters and tail in mature males)
blue/turquoise heads as a standard in both sexes, plus sex-specific advertisement-patterns elsewhere on the figure, during courtship and territorial defence (masculine) or mating and pregnancy (feminine), and
dimming of bright hues (particularly blue/turquoise on the head), within a timespan of several seconds, in apprehension of potential predators.

BASKING

The whole figure is darkened, to the point of conspicuousness.

The following (https://www.inaturalist.org/observations/183891676) may possibly be a case of darkening while basking, but it is ambivalent because of masculine advertisement (note that the vertebral stripe remains strikingly pale).

Conversely, the whole figure can show pallor to the point of conspicuousness, presumably in reaction to overheating.

Infants:

https://www.inaturalist.org/observations/56296497

Juveniles:

https://www.inaturalist.org/observations/140971098
https://www.inaturalist.org/observations/152917147
https://www.inaturalist.org/observations/140527024
https://www.inaturalist.org/observations/160779798
https://www.inaturalist.org/observations/160088637
https://www.inaturalist.org/observations/105713060
https://www.inaturalist.org/observations/101331065
https://www.inaturalist.org/observations/144260871

Adult females:

https://www.inaturalist.org/observations/66815664

Adult males:
https://www.inaturalist.org/observations/144773939

FULL CAMOUFLAGE

Infants:

https://www.inaturalist.org/observations/104927554
https://www.inaturalist.org/observations/178213828
https://www.inaturalist.org/observations/107939539
https://www.inaturalist.org/observations/106423715
https://www.inaturalist.org/observations/77415645
https://www.inaturalist.org/observations/11201198

Juveniles (sex unknown):

Adult females (most camouflaged when not in breeding condition):

Adult males (camouflaged only when not in breeding condition, and generally less likely than females to be camouflaged):

INDIVIDUAL/TEMPORARY VARIATION IN MOTTLING (with a sexual difference that hypothetically begins in small juveniles)

Juvenile females?:

Juvenile males?:

The following individual adult males (https://www.inaturalist.org/observations/135228134 and https://www.inaturalist.org/observations/122286005) are unusual in retaining mottling on the torso, at an age/stage when the head is already capable of full expression of blue.

Does the pattern of mottling on these juvenile individuals (https://www.inaturalist.org/observations/42741986 and https://www.inaturalist.org/observations/42388255) indicate female?

INDIVIDUAL/TEMPORARY VARIATION IN PALE VERTEBRAL STRIPE (a feature conspicuous only in males)

https://www.inaturalist.org/observations/135278580
https://www.inaturalist.org/observations/157098426
https://www.inaturalist.org/observations/156405081
https://www.inaturalist.org/observations/148914255
https://www.inaturalist.org/observations/147757992
https://www.inaturalist.org/observations/146445339
https://www.inaturalist.org/observations/154813177
extending on to tail https://www.inaturalist.org/observations/61882478 and https://www.inaturalist.org/observations/59758406

FEMALE AS OPPOSED TO MALE

Females in non-breeding condition:

https://www.inaturalist.org/observations/146099365
https://www.inaturalist.org/observations/143438639
https://www.inaturalist.org/observations/106260951
https://www.inaturalist.org/observations/102831109
https://www.inaturalist.org/observations/99207138
https://www.inaturalist.org/observations/39196901

Males in non-breeding condition:

The following show that, already in juvenile males,

bluish may appear on the head (https://www.inaturalist.org/observations/101514349 and https://www.dreamstime.com/stock-photo-blue-headed-agama-lizard-south-africa-image51453922 and https://www.inaturalist.org/observations/39037855),
yellowish may appear on the ventral surface of the tail (https://www.gettyimages.com.au/detail/photo/southern-rock-agama-mountain-zebra-national-park-royalty-free-image/84544671?phrase=southern+rock+agama&adppopup=true and https://www.inaturalist.org/observations/63591996 and https://www.inaturalist.org/observations/59127987), or
the pale vertebral stripe may become conspicuous (https://www.inaturalist.org/observations/101169113 and https://www.inaturalist.org/observations/70142747 and https://www.inaturalist.org/observations/65462176).

BREEDING CONDITION

Also please see other recent Posts, including https://www.inaturalist.org/posts/86639-male-and-female-phenotypes-of-the-southern-rock-agama#

Femininity:

The following (https://www.inaturalist.org/observations/60995709) shows that feminine colouration (and presumably sexual maturity) arrives in what seems to be large juveniles, long before complete body size is attained.

Masculinity:

Also see https://www.inaturalist.org/journal/milewski/86484-rock-dwelling-agamids-on-two-continents-ctenophorus-vs-agama-part-3-variation-in-masculine-colouration#.

Blue:

https://www.inaturalist.org/observations/143569591
https://www.inaturalist.org/observations/143201236
https://www.inaturalist.org/observations/92462817
https://www.inaturalist.org/observations/65073430
https://www.inaturalist.org/observations/52145437 and https://www.inaturalist.org/observations/52145427
https://www.inaturalist.org/observations/51831677

Turquoise :

https://www.inaturalist.org/observations/113189424
https://www.inaturalist.org/observations/134023368
https://www.inaturalist.org/observations/103537772
https://www.inaturalist.org/observations/58128869

Please see https://www.inaturalist.org/journal/milewski/86484-rock-dwelling-agamids-on-two-continents-ctenophorus-vs-agama-part-3-variation-in-masculine-colouration#

The following (https://www.dreamstime.com/stock-photo-southern-rock-agama-lizard-table-mountain-national-park-cape-town-south-africa-image86551322 and https://www.inaturalist.org/observations/115899303 and https://www.inaturalist.org/observations/71960640) show that bluish hues start to appear in juveniles.

Perhaps the part of the body most individually variable in colouration in masculinity is the tail (https://www.inaturalist.org/observations/100862807).

EMOTION

Dimming of bright hues:

Females:

https://www.inaturalist.org/observations/102223286
https://www.inaturalist.org/observations/190468068
https://www.inaturalist.org/observations/189509923
https://www.inaturalist.org/observations/173287949
https://www.inaturalist.org/observations/129860347
https://www.inaturalist.org/observations/59114886
https://www.inaturalist.org/observations/58128871
https://www.inaturalist.org/observations/45279980

Males:

https://www.inaturalist.org/observations/103414164
https://www.inaturalist.org/observations/101324816
https://www.inaturalist.org/observations/102981074
https://www.inaturalist.org/observations/62039159
https://www.inaturalist.org/observations/38634177

to be continued in https://www.inaturalist.org/journal/milewski/86775-a-photo-guide-to-the-bewilderingly-complex-colouration-of-the-south-african-rock-dwelling-agamid-agama-atra-part-2-discussion#...

Publicado el 10 de noviembre de 2023 a las 05:12 AM por

milewski

Comentarios

INFANTS:

https://www.inaturalist.org/observations/146466457

Anotado por milewski hace 6 meses

https://www.inaturalist.org/observations/144924413

https://www.inaturalist.org/observations/143425490

https://www.dreamstime.com/royalty-free-stock-photos-lizard-fly-image15875608

https://www.inaturalist.org/guide_taxa/717641

TEST FOR READERS #1

https://www.inaturalist.org/observations/139151718

TEST FOR READERS #2

Female or male?

https://www.inaturalist.org/observations/139566590

TEST FOR READERS #3

Female or male?:

https://www.inaturalist.org/observations/140526591

TEST FOR READERS #4

Breeding condition or not?:

https://www.inaturalist.org/observations/138290934

TEST FOR READERS #5

https://www.inaturalist.org/observations/138286762

https://www.inaturalist.org/observations/136566833

UNUSUAL PHOTO OF FEMALE AND MALE TOGETHER

https://www.inaturalist.org/observations/136050939

TEST FOR READERS #6

https://www.inaturalist.org/observations/134390852

TEST FOR READERS #7

https://www.inaturalist.org/observations/134046343

https://www.inaturalist.org/observations/133091155

https://www.inaturalist.org/observations/131930818

https://www.inaturalist.org/observations/129865433

https://www.inaturalist.org/observations/125250666

Female in breeding condition, but retaining a capacity for camouflage:

https://www.inaturalist.org/observations/123859625

Why do these two individual males differ in colouration?:

https://www.inaturalist.org/observations/112422015

TEST FOR READERS #8

https://www.inaturalist.org/observations/109768293

The following show the transition from camouflaged juvenile to conspicuous adult, on the same substrate:

https://www.inaturalist.org/observations/107278646

https://www.inaturalist.org/observations/107278635

@johannesvanrooyen

CORRECTION

Here is evidence that adult females can have a dark torso, after all.

Female:
https://www.inaturalist.org/observations/106257510
https://www.inaturalist.org/observations/63758365

Male:
https://www.inaturalist.org/observations/106257509

TEST FOR READERS #9

Immature or mature?:

https://www.inaturalist.org/observations/103419133

TEST FOR READERS #10

https://www.inaturalist.org/observations/103002884

TEST FOR READERS #11

https://www.inaturalist.org/observations/100853846

In Agama atra, the pale vertebral stripe is a) one of the most sexually dimorphic features, b) often a conspicuous feature in mature males (https://www.inaturalist.org/observations/66374093), but never a conspicuous feature in females, even in breeding condition, and c) never more prominent in females than in https://www.inaturalist.org/observations/34070094 and https://www.inaturalist.org/observations/99302915 and https://www.inaturalist.org/observations/75149459 and https://www.inaturalist.org/observations/66842668?

Juvenile female, already showing yellowish abdomen:

https://www.inaturalist.org/observations/98463157

TEST FOR READERS #12

https://www.inaturalist.org/observations/97376770

Is it really possible that a given individual female of Agama atra can change from this (https://www.inaturalist.org/observations/91255172 and https://www.inaturalist.org/observations/77732937) to this (https://www.inaturalist.org/observations/153329519), within a single year?

https://www.inaturalist.org/observations/90244936

https://www.inaturalist.org/observations/79897693

TEST FOR READERS #13

Juvenile or adult?:

https://www.inaturalist.org/observations/88765446

The following show that, in adult males, the tail - beyond its base- is laterally compressed, somewhat like a knife-blade oriented as if to cut the substrate:

https://www.inaturalist.org/observations/86474850

https://www.inaturalist.org/observations/36880256

One of the puzzling variants of masculine colouration:

https://www.inaturalist.org/observations/86045752

TEST FOR READERS #14

https://www.inaturalist.org/observations/84421616

Would Agama atra ever have this appearance
(https://www.inaturalist.org/observations/66866870) in Namibia?

TEST FOR READERS #15

https://www.inaturalist.org/observations/65847331

TEST FOR READERS #16

https://www.inaturalist.org/observations/63949569

Females in breeding condition:

https://www.inaturalist.org/observations/61772443

https://www.inaturalist.org/observations/61032132

The following shows that the yellowish hue on the torso of females (in this case juvenile) does not lose its chroma in death:

https://www.inaturalist.org/observations/61457200

TEST FOR READERS #17

https://www.inaturalist.org/observations/57223625

https://www.inaturalist.org/observations/55198614

https://www.inaturalist.org/observations/43289715

A remarkable illustration of camouflage in Agama atra:

https://www.inaturalist.org/observations/41626481

https://www.inaturalist.org/observations/156509003

https://www.inaturalist.org/observations/37622476

https://www.inaturalist.org/observations/37622469

The following photos are unusual in that) female and male are shown together, in breeding condition, and b) in one case, the female individual shows a conspicuous pale vertebral stripe:

https://www.inaturalist.org/observations/10954776

https://www.inaturalist.org/observations/37109579

https://www.inaturalist.org/observations/9481441

Also see https://www.inaturalist.org/observations/9247148