Rock-dwelling agamids on two continents: Ctenophorus vs Agama, part 1: illustrations

Additional illustrations of conspicuous hues in females and juveniles of Agama planiceps:

https://www.inaturalist.org/observations/496617

https://www.inaturalist.org/observations/114162543

https://www.inaturalist.org/observations/104173241

https://www.inaturalist.org/observations/93150052

https://www.inaturalist.org/observations/78815575

https://www.inaturalist.org/observations/14985644

https://www.inaturalist.org/observations/12979943

https://www.inaturalist.org/observations/10033207

http://danielhoops.com/blog/2014/6/4/rock-dragon-group-2

https://www.wesreadphotography.com/blog/sa-dragons-2022-part-2

https://www.researchgate.net/publication/335899948_Reproduction_predation_sexual_dimorphism_and_diet_in_Agama_anchietae_Reptilia_Agamidae_from_Namibia:

Agama anchietae differs from A. planiceps in being smaller-bodied, less sexually dimorphic, solitary as opposed to social, not polygynous to the same degree, and inconspicuous in colouration.

The diets are similar (ants, termites, and other insects), except that anchietae does not eat beetles as frequently as does planiceps.

Agama anchietae lays more eggs per clutch than does A. planiceps, compensating by the eggs being relatively small.

I infer that the two species coexist at the hectare scale, despite belonging to the same genus, and having similar diets.

It is not habitat or diet that separate them, but instead social/sexual/reproductive strategy, and anti-predator strategy. Agama planiceps, unlike A. anchietae, is large, conspicuous, and particularly social/polygynous.

https://www.cambridge.org/core/journals/journal-of-zoology/article/abs/skeletochronology-and-markrecapture-assessments-of-growth-in-the-north-african-agamid-lizard-agama-impalearis/3FCDC781AF4979A283C06762D48889E4

https://www.jstor.org/stable/1566202
https://www.researchgate.net/publication/250071322_A_Comparison_of_the_Breeding_and_Nonbreeding_Season_Diets_of_Agama_aculeata_and_Agama_planiceps_Reptilia_Agamidae_in_Windhoek_Namibia

This reference shows, in detail, that Agama planiceps eats mainly ants. The only species of termite eaten is Hodotermes mossambicus.

https://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-23f268d4-f349-4bed-b0b2-28cab0cc3a27

Information on the Web, for snout-vent lengths in rupicolous spp. of Agama, is limited. This hinders comparison with Ctenophorus, in which snout-vent length is the usually-reported measure of body size (the rock-dwelling spp. have snout-vent lengths of about 7-10 cm).

Agama atra is known to have snout-vent length about 9 cm in females, and about 12.5 cm in males (Bruton, 1977).

Agama agama is not specialised for rock-dwelling (Harris, 1964, https://www.amazon.com/Life-Rainbow-Lizard-V-Harris/dp/0090721403 and https://www.biblio.com/book/life-rainbow-lizard-harris-v/d/1288437620).

Enge et al. (2004, https://www.jstor.org/stable/24321176) state that adult females of A. agama have snout-vent length 9.4 cm or more. This indicates that A. agama exceeds A, atra in body size.

A study at the delta of the Niger River (https://abjournals.org/african-journal-of-biology-and-medical-research-ajbmr/wp-content/uploads/sites/17/journal/published_paper/volume-3/issue-1/AJBMR_IgtNPMp9.pdf) further documents A. agama.

However, a) both adults and juveniles were sampled (which is not stated in the Methods but is evident from the ranges of values of body size), and b) what is stated to be 'snout-vent length' seems actually to be total length.

The authors sampled of 151 individuals of the two sexes combined, in February to May.

They do not state whether females were gravid or not. However, I infer that they were not at this time, because sampling was done late in the dry season.

The findings, for A. agama, are:

Females (not necessarily adult):
Mean body mass 20-22 g
Total length ('misreported as 'snout vent length') 18-20.5 cm

Males (not necessarily mature):
Mean body mass 48-51 g
Total length (misreported as 'snout vent length') 26.5 cm

I infer from these poorly-presented data that, in A. agama, adult females have total length about 28 cm and body mass about 45 g, whereas mature males have total length about 32 cm and body mass about 70 g.

Agama planiceps is similar to A. agama (which is large-bodied for its genus) in body size. Thus, the body mass of adult females of A. planiceps is double that typical for adult females of rock-dwelling spp. of Ctenophorus.

I infer that A. planiceps is not only more social/gregarious/colonial than any counterpart in Australia, but also larger-bodied - even if we correct for the extreme sexual dimorphism in A. planiceps

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1600-0587.1999.tb00503.x

This reference gives asymptotic snout-vent lengths as Agama impalearis = bibronii (https://www.inaturalist.org/taxa/1367368-Agama-bibronii) grows to adulthood.

Near Marrakech (https://en.wikipedia.org/wiki/Marrakesh) in Morocco, asymptotic snout-vent length has mean values of a) 12.5 cm in males, and b) 11.4 cm in females.

Sexual maturity occurs at mean snout-vent length of a) 9.1 cm in males, and b) 8.8 cm in females.

Within Morocco, the asymptotic snout-vent lengths of males vary from means of about 13 cm in the southwest of the country to means of about 12 cm in the northeast of the country.

These are the most reliable data that I have found, so far, for snout-vent lengths in any rupicolous spp. of Agama. How do they compare with Ctenophorus?

(An obvious caveat is that Agama impalearis = bibronii occurs in North Africa, whereas my study is in southern Africa.)

Well, snout-vent lengths for adults of Ctenophorus spp. are about 7-10 cm.

This indicates that body size is considerably greater in rupicolous Agama (snout-vent lengths > 11.5 cm) than in rupicolous Ctenophorus (snout-vent lengths < 10 cm).

https://www.researchgate.net/profile/El-Hassan-El-Mouden/publication/249645371_Sexual_dimorphism_reproductive_and_fat_body_cycles_in_Bibron%27s_agama_Agama_impalearis_Boettger_1874Sauria_Agamidae/links/55b8ad7808ae9289a08dd62b/Sexual-dimorphism-reproductive-and-fat-body-cycles-in-Bibrons-agama-Agama-impalearis-Boettger-1874Sauria-Agamidae.pdf

AGAMA BIBRONII = IMPALEARIS

Central Jbilet mountains, Morocco

"mature males ranged from 91-134 mm SVL and from 25.5-100 g in mass, and mature females ranged from 88-125 mm SVL and from 27-85 g in mass (excluding clutch mass in gravid females). The mean SVL was of 113.09...mm and 105.77...mm, respectively for males and females corresponding to average body masses of 62.60...g and 51.78...g.

I note that body mass of adult females in this species exceeds that of any of the southern African rock-dwelling congeners.

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1442-9993.2010.02113.x