Fossil Primates

Cachel, Susan

doi:10.1017/cbo9780511793844

Cited by 7 publications

(8 citation statements)

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“…A steep temperature drop characterized the Eocene–Oligocene transition when the Antarctic Circumpolar Cold Current developed (Burke & Gunnell ; Feakins & Demenocal ). This caused a latitudinal temperature gradient with seasonality at high latitudes, and the start of the cold Benguela Current along the Southern Africa West Coast (Burke & Gunnell ; Morley & Kingdon ; Cachel ). In all likelihood, tectonic uplift over the past 30 My (Burke & Gunnell ; Rudge et al .…”

Section: Discussionmentioning

confidence: 99%

“…The raised eastern escarpment acted as a rain shadow to reduce rainfall in the interior (Neumann & Bamford ) and contributed to grassland expansion by the Miocene (McCarthy & Rubidge ). Overall, the Oligocene is considered an epoch of global aridity (Cachel ). This epoch has also been indicated as a time for diversification of other Southern African reptiles, for example Cordylinae (Stanley et al .…”

Section: Discussionmentioning

confidence: 99%

“…Radiations in Chersobius (18–14 Mya) and P. tentorius (15–7 Mya) coincided with a temperature and rainfall increase that lasted from the Late Oligocene to Mid‐Miocene (Zachos et al . ; Cachel ). The three Chersobius species are rock‐dwelling and arid‐adapted taxa that occur, respectively, in the westerly winter‐rainfall Succulent Karoo of South Africa ( signatus ) and Namibia ( solus ), and the summer‐rainfall Nama Karoo ( boulengeri ) of South Africa (Branch ).…”

Section: Discussionmentioning

confidence: 99%

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Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present

et al. 2016

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Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present. -Zoologica Scripta, 46, 389-400. Africa, inclusive of the West Indian Ocean islands, harbours 11 of the world's 16 extant testudinid genera. Fossil records indicate that testudinids originated in Asia and dispersed first to North America and Europe (Early Eocene) and later to Africa (Late Eocene). We used mitochondrial (1870 bp) and nuclear (1416 bp) DNA sequence data to assess whether molecular data support the late cladogenesis of Southern African testudinid lineages. Our results revealed strong support for the monophyly of a clade consisting of Kinixys, the two Malagasy genera and four Southern African genera (Psammobates, Stigmochelys, Homopus and Chersina). Kinixys diverged from this clade in the Late Palaeocene, suggesting that testudinids occupied Africa at an earlier date than indicated by fossil records. The Southern African tortoises consist of three, strongly supported clades: Psammobates + Stigmochelys; the five-toed Homopus + Chersina; and the four-toed Homopus. Due to the paraphyly of Homopus, we propose the taxonomic resurrection of Chersobius for the five-toed Homopus species (boulengeri, signatus and solus). Cladogenesis at the genus level occurred mainly in the Eocene, with Chersina and Chersobius diverging in the Oligocene. The latter divergence coincided with species-level radiations within Homopus (areolatus and femoralis) and Psammobates (oculifer, geometricus and tentorius). Our phylogeny could not resolve relationships within Psammobates, indicating rapid speciation between the Late Oligocene and Early Miocene. The Chersobius species were the last to diverge in the Early to Mid-Miocene. By the Mid-Miocene, P. tentorius started to differentiate into four lineages instead of the three recognized subspecies: P. t. tentorius, P. t. trimeni and two P. t. verroxii subclades occurring north and south of the Orange River, respectively. Terminal radiations in several taxa suggest the existence of cryptic species and a more diverse tortoise fauna than currently recognized. Factors contributing to this diversity may include the early origin of African testudinids and climatic fluctuations over a heterogeneous landscape.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present

et al. 2016

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“…Most investigators postulate that the postorbital septum evolved as an extension of the existing POB in euprimates (e.g., Cartmill, ; Cachel, ). However, the earliest near relatives of euprimates, if derived from stock within Plesiadipiformes, may have supported their eyes in a different way.…”

Section: Discussionmentioning

confidence: 99%

“…An understanding of the arrangement of soft tissue support in these taxa is also of interest because of the anatomical diversity among early primates. Those with a POB had both relatively large (some early haplorhines) as well as unenlarged eyes (early strepsirrhines), while stem primates, which lacked a POB, had small eyes (Szalay and Delson, ; Fleagle, ; Cachel, ).…”

Section: Introductionmentioning

confidence: 99%

Membranous Support for Eyes of Strepsirrhine Primates and Fruit Bats

Harvey

Bhatnagar

Schenck

et al. 2016

The Anatomical Record

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Living primates have relatively large eyes and support orbital tissues with a postorbital bar (POB) and/or septum. Some mammals with large eyes lack a POB, and presumably rely on soft tissues. Here, we examined the orbits of four species of strepsirrhine primates (Galagidae, Cheirogaleidae) and three species of fruit bats (Pteropodidae). Microdissection and light microscopy were employed to identify support structures of the orbit. In bats and primates, there are two layers of fascial sheets that border the eye laterally. The outer membrane is the most superficial layer of deep fascia, and has connections to the POB in primates. In fruit bats, which lacked a POB or analogous ligament, the deep fascia is reinforced by transverse ligaments. Bats and primates have a deeper membrane supporting the eye, identified as the periorbita (PA) based on the presence of elastic fibers and smooth muscle. The PA merges with periostea deep within the orbit, but has no periosteal attachment to the POB of primates. These findings demonstrate that relatively big eyes can be supported primarily with fibrous connective tissues as well as the PA, in absence of a POB or ligament. The well-developed smooth muscle component within the PA of fruit bats likely helps to protrude the eye, maintaining a more convergent eye orientation, with greater overlap of the visual fields. The possibility should be considered that early euprimates, and even stem primates that may have lacked a POB, also had more convergent eyes than indicated by osseous measurements of orbital orientation.

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An Introduction to Space Anthropology

Smith

2019

Principles of Space Anthropology

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Fossil Primates

Cited by 7 publications

References 0 publications

Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present

Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present

Membranous Support for Eyes of Strepsirrhine Primates and Fruit Bats

An Introduction to Space Anthropology

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