The Platypleurini is a large group of charismatic cicadas distributed from Cape Agulhas in South Africa, through tropical Africa, Madagascar, India and eastern Asia to Japan, with generic diversity concentrated in equatorial and southern Africa. This distribution suggests the possibility of a Gondwanan origin and dispersal to eastern Asia from Africa or India. We used a four‐gene (three mitochondrial) molecular dataset, fossil calibrations and molecular clock information to explore the phylogenetic relationships of the platypleurine cicadas and the timing and geography of their diversification. The earliest splits in the tribe were found to separate forest genera in Madagascar and equatorial Africa from the main radiation, and all of the Asian/Indian species sampled formed a younger clade nested well within the African taxa. The tribe appears to have diversified during the Cenozoic, beginning
A neotropical wet-forest snake lineage from the Early Miocene of equatorial Africa: biogeographic and paleoenvironmental implications
The highest species richness and ecological diversity of extant snakes are in the tropics, primarily in South
Asia and Central and South America. Tropical Africa has relatively lower richness and less diversity, but
the evolution of tropical herpetofaunas, and the factors governing diversification through time at
continental scales are poorly understood due to an understudied fossil record. The ecologies and
geographic distributions of aniliid and uropeltoid snakes are examples. Modern species constitute
either a grade or clade of fossorial, primarily wet forest taxa from South America and South Asia.
Their distributions have historically been interpreted as Gondwanan vicariance following the isolation of
Africa in the Early Cretaceous, but a definitive fossil record for these snakes is depauperate.
Field research in the early Miocene (approx. 19 Mya) Tinderet sequence of western Kenya has produced
precloacal vertebrae of an aniliid snake from multiple localities. Specimens possess vertebral apomorphies
shared with extant South American Anilius scytale, including the morphology of the neural spine and
prezygapophyseal angle. Combined with additional fossils from the Eocene of North Africa, the Tinderet
records demonstrate an unambiguous past record of an extant neotropical snake lineage in Africa and
falsify previous vicariance hypotheses. Recent stable isotopic and palynological studies of Neogene eastern
African fossil localities have indicated heterogenous environments, including C4 grasses and wood- to
scrubland, associated with vertebrate faunas. Comparing climate parameters of habitats for extant
Anilius and uropeltoid snakes as ecological analogues to the Tinderet snake with modern ecosystems
equivalent to those reconstructed for the eastern African early Miocene demonstrates only limited
overlap in precipitation and temperature values. This discord indicates either greater environmental
heterogeneity than reconstructed for the early Miocene of eastern Africa, or a greater range of
habitat variability in aniliid snakes than observed in extant Anilius.
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- Award ID(s):
- 2123497
- NSF-PAR ID:
- 10471049
- Publisher / Repository:
- Journal of Vertebrate Paleontology, Program and Abstracts
- Date Published:
- Volume:
- 2023
- Page Range / eLocation ID:
- 208
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract c . 50–32 Ma, with most extant African lineages originating in the Miocene or later, well after the breakup of the Gondwanan landmass. Biogeographical analysis suggests an African origin for the tribe and a single dispersal event founding the Asian platypleurines, although additional taxon sampling and genetic data will be needed to confirm this pattern because key nodes in the tree are still weakly supported. Two Platypleurini genera from Madagascar (Pycna Amyot & Audinet‐Serville,Yanga Distant) are found to have originated by late Miocene dispersal of a single lineage from Africa. The genusPlatypleura is recovered as polyphyletic, withPlatypleura signifera Platypleura concept is proposed with the synonymization ofAzanicada Villetsyn.n. The generaOrapa Distant andHamza Distant, currently listed within separate tribes but suspected of platypleurine affinity, are nested deeply within the Platypleurini radiation. The tribe Orapinisyn.n . is here synonymized while the tribe Hamzini is pending a decision of the ICZN to preserve nomenclatorial stability. -
null (Ed.)Fossil cercopithecid primates of the African Plio-Pleistocene are often found together in fossil deposits across East and South Africa. These species may have co-occurred in life and exploited similar types of resources in shared environments, as extant monkeys in Africa and Asia are known to do. Some of these fossil species are represented today by congeneric or descendant species with similar adaptations while others have no modern analogue. This project uses dental morphology to compare community structure across potentially co-occurring fossil and modern cercopithecid populations (the cercopithecid taxocene). Relative enamel thickness, shearing potential, and dental shape ratios from the P4 – M3 toothrow were measured from extant (n > 700) and fossil cercopithecid specimens (n > 1000). The latter primarily targeted the Hadar, Shungura, and Koobi Fora Formations of East Africa and the sites of Makapansgat, Sterkfontein, and Swartkrans in South Africa. Principal component analyses were performed separately on the maxillary and mandibular dentitions and resulting component scores were used to reconstruct the taxocene dental morphology at each site. In general, the African cercopithecid taxocene is similar across the main fossil sites analyzed. Patterns of overlap between fossil and modern sites may reflect environmental similarities or the adaptability of generalist cercopithecids. An apparent niche shift from the Plio-Pleistocene to today reflects both taphonomic and ecological factors: a lack of smaller-bodied fossil cercopithecin and colobine species combined with an expanded dental ecomorphological niche of larger-bodied fossil species.more » « less
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Mammals rose to prominence in terrestrial ecosystems after the Cretaceous–Paleogene mass extinction, but the mammalian lineages characteristic of Paleogene faunas began their evolutionary and ecological diversification in the Late Cretaceous, stimulated by the rise of angiosperms (flowering plants) according to the preeminent hy- pothesis. The Cretaceous rise of mammals is part of a larger expansion in biodiversity on land that has been termed the Cretaceous (or Angiosperm) Terrestrial Revolution, but the mechanisms underlying its initiation remain opaque. Here, we review data from the fossil and rock records of western North America—due to its relatively continuous fossil record and complete chronology of mountain-building events—to explore the role that tectonism might have played in catalyzing the rise of modern-aspect terrestrial biodiversity, especially that of mammals and angiosperms. We highlight that accelerated increases in mammal and angiosperm species richness in the Late Cretaceous, ca. 100–75 Ma, track the acceleration of tectonic processes that formed the North American Cordillera and occurred during the ‘middle-Cretaceous greenhouse’ climate. This rapid increase in both mammal and angiosperm diversity also occurred during the zenith of Western Interior Seaway trans- gression, a period when the availability of lowland habitats was at its minimum, and oscillatory transgression- regression cycles would have frequently forced upland range shifts among lowland populations. These changes to both landscapes and climates have all been linked to an abrupt, global tectonic-plate ‘reorganization’ that occurred ca. 100 Ma. That mammals and angiosperms both increased in species richness during this interval does not appear to be a taphonomic artifact—some of the largest spikes in diversity occur when the available mammal-bearing fossil localities are sparse. Noting that mountainous regions are engines for generating biodi- versity, especially in warm climates, we propose that the Cretaceous/Angiosperm Terrestrial Revolution was ultimately catalyzed by accelerated tectonism and enhanced via cascading changes to landscapes and climate. In the fossil record of individual basins across western North America, we predict that (1) increases in mammalian diversity through the Late Cretaceous should be positively correlated with rates of tectonic uplift, which we infer to be a proxy for topographic relief, and are attended by increased climate heterogeneity, (2) the diversity of mountain-proximal mammalian assemblages should exceed that of coeval mountain-distal assemblages, espe- cially in the latest Cretaceous, and (3) endemism should increase from the latest Cretaceous to early Paleogene as Laramide mountain belts fragmented the Western Interior. Empirical tests of these predictions will require increased fossil collecting in under-sampled regions and time intervals, description and systematic study of existing collections, and basin-scale integration of geological and paleontological data. Testing these predictions will further our understanding of the coevolutionary processes linking tectonics, climate, and life throughout Earth history.more » « less
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