The black-necked agama (''Acanthocercus atricollis'') is a species of
tree agama that is native to
East,
Central
Central is an adjective usually referring to being in the center of some place or (mathematical) object.
Central may also refer to:
Directions and generalised locations
* Central Africa, a region in the centre of Africa continent, also known as ...
and
southern Africa. Its largest continuous range is in southeastern Africa, and it occurs at high densities in the
Kruger National Park
Kruger National Park is a South African National Park and one of the largest game reserves in Africa. It covers an area of in the provinces of Limpopo and Mpumalanga in northeastern South Africa, and extends from north to south and from ea ...
.
[
]
Description
The sexes have a comparable snout-to-vent length (SVL) and have similar tail lengths. Mature males have somewhat larger heads than females, which is deemed to be an adaptation for intraspecific competition for territory. Females reach sexual maturity when about 96 mm long (SVL) and males from about 82 mm (SVL).[
]
Habits
They form structured colonies with a dominant male, several females and juveniles. The males defend territories and engage in combat. Although mostly diurnal, they sometimes exhibit nocturnal activity.[ This involves an average of less than one movement in two minutes. When stationary, the adults position themselves on lateral branches (42% of the time), on tree trunks (35%), or occasionally on the ground (23%).][
]
Diet
They subsist on an insect diet, which consists mainly of orthoptera
Orthoptera () is an order of insects that comprises the grasshoppers, locusts, and crickets, including closely related insects, such as the bush crickets or katydids and wētā. The order is subdivided into two suborders: Caelifera – grassho ...
ns, beetles and ants.[ Their full diet encompasses various orders (10 recorded) of arthropods. They also eat millipedes, which other lizard taxa tend to avoid. Gut contents reveal many ants (92% of items) and some beetles (4%).][ A large volume of orthopterans is consumed (27%), followed by beetles (26%) and ants (18%). Juvenile diet (by volume) is dominated by ants, though beetles and orthopterans are also taken. Prey diversity and volumes fluctuate seasonally.][
]
Reproduction
Reproduction is seasonal. Testicular volume of males reaches a maximum during August to September (austral spring), and follicles of females become enlarged during August to December.[ Females lay a single clutch per annum, about 11 eggs on average, and larger females produce larger clutches than smaller females.][
]
Range
It is found in Eritrea
Eritrea ( ; ti, ኤርትራ, Ertra, ; ar, إرتريا, ʾIritriyā), officially the State of Eritrea, is a country in the Horn of Africa region of Eastern Africa, with its capital and largest city at Asmara. It is bordered by Ethiopia ...
, Somalia, Ethiopia, Sudan
Sudan ( or ; ar, السودان, as-Sūdān, officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is a country in Northeast Africa. It shares borders with the Central African Republic t ...
, South Sudan, Uganda, D.R.C., Kenya, Tanzania, Zambia, Malawi, Mozambique, Zimbabwe, Angola, Botswana, Namibia, South Africa and Eswatini
Eswatini ( ; ss, eSwatini ), officially the Kingdom of Eswatini and formerly named Swaziland ( ; officially renamed in 2018), is a landlocked country in Southern Africa. It is bordered by Mozambique to its northeast and South Africa to its no ...
.[
]
Races
Two races are usually accepted. Four more have been described however, which are not very distinct.
Gallery
Image:Acanthocercus atricollis.jpg, Proposed race ''A. a. kiwuensis'' (Klausewitz, 1957) at Lake Kivu
Image:Southern Tree Agama (Acanthocercus atricollis) female (32100887592).jpg,
Image:Southern Tree Agamas (Acanthocercus atricollis) couple (31159640691).jpg,
Image:Acanthocercus atricollis03.jpg,
References
{{Taxonbar, from=Q653785
Acanthocercus
Reptiles of Africa
Reptiles described in 1849
Taxa named by Andrew Smith (zoologist)