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

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.

https://www.inaturalist.org/observations/189979385
https://www.inaturalist.org/observations/151220981
https://www.inaturalist.org/observations/148808808
https://www.inaturalist.org/observations/143339975
https://www.inaturalist.org/observations/142361930
https://www.inaturalist.org/observations/137461357
https://www.inaturalist.org/observations/133750353
https://www.inaturalist.org/observations/129252633
https://www.inaturalist.org/observations/108127353
https://www.inaturalist.org/observations/99271711
https://www.inaturalist.org/observations/97456305
https://www.inaturalist.org/observations/92893591
https://www.inaturalist.org/observations/91614283
https://www.inaturalist.org/observations/61149294
https://www.inaturalist.org/observations/11037337

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):

https://www.inaturalist.org/observations/189834985
https://www.inaturalist.org/observations/190401856
https://www.inaturalist.org/observations/184233155
https://www.inaturalist.org/observations/143626898
https://www.inaturalist.org/observations/141807682
https://www.inaturalist.org/observations/140359983
https://www.inaturalist.org/observations/135228293
https://www.inaturalist.org/observations/134083950
https://www.inaturalist.org/observations/109144536
https://www.inaturalist.org/observations/106978716
https://www.inaturalist.org/observations/106068094
https://www.inaturalist.org/observations/99779395
https://www.inaturalist.org/observations/99090876
https://www.inaturalist.org/observations/66135305
https://www.inaturalist.org/observations/39583476
https://www.inaturalist.org/observations/80725769
https://www.inaturalist.org/observations/145117332

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

https://www.inaturalist.org/observations/94229299
https://www.inaturalist.org/observations/145090147
https://www.inaturalist.org/observations/101458977
https://www.inaturalist.org/observations/143257145
https://www.inaturalist.org/observations/102723755
https://www.inaturalist.org/observations/181591198
https://www.inaturalist.org/observations/105161873
https://www.inaturalist.org/observations/105098356
https://www.inaturalist.org/observations/104589845
https://www.inaturalist.org/observations/105950128
https://www.inaturalist.org/observations/105762468
https://www.inaturalist.org/observations/139538304
https://www.inaturalist.org/observations/106175608
https://www.inaturalist.org/observations/105500801
https://www.inaturalist.org/observations/99653069
https://www.inaturalist.org/observations/76897806
https://www.inaturalist.org/observations/59793234
https://www.inaturalist.org/observations/11345063
https://www.inaturalist.org/observations/10942583

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

https://www.inaturalist.org/observations/80509867
https://www.inaturalist.org/observations/95245809
https://www.inaturalist.org/observations/96783628
https://www.inaturalist.org/observations/105032446
https://www.inaturalist.org/observations/105211330
https://www.inaturalist.org/observations/104565190
https://www.inaturalist.org/observations/182312800
https://www.inaturalist.org/observations/146044256
https://www.inaturalist.org/observations/77415641
https://www.inaturalist.org/observations/76701722
https://www.inaturalist.org/observations/65034274
https://www.inaturalist.org/observations/40828892
https://www.inaturalist.org/observations/33325519

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

Juvenile females?:

https://www.inaturalist.org/observations/102022282
https://www.inaturalist.org/observations/113484074
https://www.inaturalist.org/observations/186663137
https://www.inaturalist.org/observations/182428772
https://www.inaturalist.org/observations/179035054
https://www.inaturalist.org/observations/153667784
https://www.inaturalist.org/observations/146344391
https://www.inaturalist.org/observations/144145227
https://www.inaturalist.org/observations/137654137
https://www.inaturalist.org/observations/61072158
https://www.inaturalist.org/observations/20160000
https://www.inaturalist.org/observations/11119536

Juvenile males?:

https://www.inaturalist.org/observations/10937019
https://www.inaturalist.org/observations/185887296
https://www.inaturalist.org/observations/106068094
https://www.inaturalist.org/observations/134619754
https://www.inaturalist.org/observations/178858568
https://www.inaturalist.org/observations/158040076
https://www.inaturalist.org/observations/150670850
https://www.inaturalist.org/observations/142865290
https://www.inaturalist.org/observations/142591703
https://www.inaturalist.org/observations/62047147
https://www.inaturalist.org/observations/99026500
https://www.inaturalist.org/observations/105977181
https://www.inaturalist.org/observations/125577342
https://www.inaturalist.org/observations/37635983
https://www.inaturalist.org/observations/36880256

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:

https://www.inaturalist.org/observations/105146336
https://www.inaturalist.org/observations/120946097
https://www.inaturalist.org/observations/133862559
https://www.inaturalist.org/observations/116955657
https://www.inaturalist.org/observations/116857050
https://www.inaturalist.org/observations/106242148
https://www.inaturalist.org/observations/103578843
https://www.inaturalist.org/observations/102757648
https://www.inaturalist.org/observations/97327706
https://www.inaturalist.org/observations/95685130
https://www.inaturalist.org/observations/76110533
https://www.inaturalist.org/observations/74914638
https://www.inaturalist.org/observations/63969785
https://www.inaturalist.org/observations/61287210
https://www.inaturalist.org/observations/40517363
https://www.inaturalist.org/observations/96370988

The following show that, already in juvenile males,

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:

https://www.inaturalist.org/observations/146468039
https://www.inaturalist.org/observations/173465276
https://www.inaturalist.org/observations/173464815
https://www.inaturalist.org/observations/153329519
https://www.inaturalist.org/observations/105045352
https://www.inaturalist.org/observations/100586010
https://www.inaturalist.org/observations/37026553
https://www.inaturalist.org/observations/103460893
https://www.inaturalist.org/observations/103422833
https://www.inaturalist.org/observations/173465276

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#...

Posted on November 10, 2023 05:12 AM by milewski milewski

Comments

Posted by milewski 8 months ago

TEST FOR READERS #2

Female or male?

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

Posted by milewski 8 months ago

TEST FOR READERS #3

Female or male?:

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

Posted by milewski 8 months ago

TEST FOR READERS #4

Breeding condition or not?:

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

Posted by milewski 8 months ago

TEST FOR READERS #5

Female or male?:

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

Posted by milewski 8 months ago

UNUSUAL PHOTO OF FEMALE AND MALE TOGETHER

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

Posted by milewski 8 months ago

TEST FOR READERS #6

Female or male?:

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

Posted by milewski 8 months ago

TEST FOR READERS #7

Female or male?:

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

Posted by milewski 8 months ago

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

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

Posted by milewski 8 months ago

Why do these two individual males differ in colouration?:

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

Posted by milewski 8 months ago

TEST FOR READERS #8

Female or male?:

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

Posted by milewski 8 months ago

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

Posted by milewski 8 months ago
Posted by milewski 8 months ago

TEST FOR READERS #9

Immature or mature?:

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

Posted by milewski 8 months ago

TEST FOR READERS #10

Breeding condition or not?:

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

Posted by milewski 8 months ago

TEST FOR READERS #11

Female or male?:

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

Posted by milewski 8 months ago

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?

Posted by milewski 8 months ago

Juvenile female, already showing yellowish abdomen:

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

Posted by milewski 8 months ago

TEST FOR READERS #12

Female or male?:

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

Posted by milewski 8 months ago

@johannesvanrooyen

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?

Posted by milewski 8 months ago

TEST FOR READERS #13

Juvenile or adult?:

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

Posted by milewski 8 months ago

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

Posted by milewski 8 months ago

One of the puzzling variants of masculine colouration:

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

Posted by milewski 8 months ago

TEST FOR READERS #14

Female or male?:

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

Posted by milewski 8 months ago

@johannesvanrooyen

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

Posted by milewski 8 months ago

TEST FOR READERS #15

Juvenile or adult?:

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

Posted by milewski 8 months ago

TEST FOR READERS #16

Female or male?:

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

Posted by milewski 8 months ago

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

Posted by milewski 8 months ago

TEST FOR READERS #17

Juvenile or adult?:

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

Posted by milewski 8 months ago

A remarkable illustration of camouflage in Agama atra:

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

Posted by milewski 8 months ago

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

Posted by milewski 8 months ago

@johannesvanrooyen

Can you spot any errors in this Post?

Posted by milewski 8 months ago

Has any reader observed this colouration in the Western Cape?:

https://www.inaturalist.org/observations/32055260

Posted by milewski 8 months ago

TEST FOR READERS #18

Female or male?:

https://www.inaturalist.org/observations/9977096

Posted by milewski 8 months ago

TEST FOR READERS #19

Female or male?:

https://www.inaturalist.org/observations/11191262

Posted by milewski 8 months ago

TEST FOR READERS #20

Female or male?:

https://www.inaturalist.org/observations/11110502

Posted by milewski 8 months ago

TEST FOR READERS #21

Female or male?:

https://www.inaturalist.org/observations/10807376

Posted by milewski 8 months ago

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