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Wednesday, August 24th, 2022
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| 2:47a | [Botany • 2022] Vepris teva (Rutaceae) • Chemistry, Taxonomy and Ecology of the potentially Chimpanzee-dispersed Vepris endangered in Coastal Thicket in the Congo Republic
Abstract Continuing a survey of the chemistry of species of the largely continental African genus Vepris, we investigate a species previously referred to as Vepris sp. 1 of Congo. From the leaves of Vepris sp. 1 we report six compounds. The compounds were three furoquinoline alkaloids, kokusaginine (1), maculine (2), and flindersiamine (3), two acridone alkaloids, arborinine (4) and 1-hydroxy-3-methoxy-10-methylacridone (5), and the triterpenoid, ß-amyrin (6). Compounds 1–4 are commonly isolated from other Vepris species, compound 5 has been reported before once, from Malagasy Vepris pilosa, while this is the first report of ß-amyrin from Vepris. This combination of compounds has never before been reported from any species of Vepris. We test the hypothesis that Vepris sp. 1 is new to science and formally describe it as Vepris teva, unique in the genus in that the trifoliolate leaves are subsessile, with the median petiolule far exceeding the petiole in length. Similar fleshy-leathery four-locular syncarpous fruits are otherwise only known in the genus in Vepris glaberrima (formerly the monotypic genus Oriciopsis Engl.), a potential sister species, but requiring further investigation to confirm this phylogenetic position. We briefly characterise the unusual and poorly documented Atlantic coast equatorial ecosystem, where Vepris teva is restricted to evergreen thicket on white sand, unusual in a genus usually confined to evergreen forest. This endemic-rich ecosystem with a unique amphibian as well as plants, extends along the coastline from the mouth of the Congo River to southern Rio Muni, a distance of about 1,000 km, traversing five countries. We map and illustrate Vepris teva and assess its extinction risk as Endangered (EN B1ab(iii)+B2ab(iii)) using the IUCN, 2012 standard. Only three locations are known, and threats include port and oil refinery construction and associated activities, with only one protected location, the Jane Goodall Institute’s Tchimpounga Reserve. Initial evidence indicates that the seeds of Vepris teva are dispersed by chimpanzees, previously unreported in the genus.
Vepris teva Cheek sp. nov. Diagnosis: differs from all known trifoliolate species of Vepris in the median petiolule far exceeding the petiole in length (usually by a factor of 2–4 times) on reproductive stems, especially near the stem apex (vs petiole exceeding petiolule in length in all other species). Most similar to Vepris glaberrima (Engl.) J.B.Hall ex D.J. Harris in the soft, leathery-fleshy, four-loculed, and slightly lobed, subverrucate syncarpous fruit, differing in the inflorescences exceeding the petiole in length (vs shorter than the petioles), the secondary nerves (10–)11–16(–18) on each side of the midrib (vs 20–30), the leaflet apices shortly rounded-acuminate (vs long, acutely acuminate) and other characters shown in Table 1 above. Etymology. Named for Teva Kami, lead collector of the type specimen, who played a key role in the discovery of this species and further research upon it concerning interactions with chimpanzees (see below). Moses K. Langat, Teva Kami and Martin Cheek. 2022. Chemistry, Taxonomy and Ecology of the potentially Chimpanzee-dispersed Vepris teva sp.nov. (Rutaceae) endangered in Coastal Thicket in the Congo Republic. PeerJ. 10:e13926. DOI: 10.7717/peerj.13926 | ||||||
| 8:44a | [Paleontology • 2022] Taphonomy of Drought afflicted Tetrapods in the Early Triassic Karoo Basin, South Africa
Highlights: • Outcrop containing hundreds of Early Triassic tetrapod fossils interpreted as evidence of drought. • Clusters of articulated skeletons interpreted as drought-induced aggregations. • Mummified skin on spreadeagled Lystrosaurus suggest rapid desiccation after death by starvation. • Bone histology confirms that all the Lystrosaurus were juveniles or early sub-adult. • Bonebeds of juvenile Lystrosaurus are interpreted as sheet-washed behavioural aggregations. Abstract The sedimentology and taphonomy of in-situ fossils from earliest Triassic strata (Induan) in the southern Karoo Basin of South Africa is presented as evidence for episodes of drought-induced mass death of the resident tetrapods. Abundant skeletons are preserved in a 2 m-thick tabular silty-sandstone capping a multi-storeyed low-sinuosity channel sandstone interpreted as a wide shallow channel that became progressively abandoned, with more ephemeral flow regime than in the underlying channels and subjected to intermittent flows of low-density sediment-laden floodwaters. Stratigraphic and planimetric distribution of 170 in-situ tetrapod fossils shows several clusters of up to eight closely-spaced articulated Lystrosaurus skeletons preserved in prone and spread-eagled body position. These are interpreted as drought-stricken carcasses that collapsed and died of starvation in and alongside dried-up water sources. Two of the specimens display an unusual micritic envelope with a distinctive pustular texture interpreted as permineralised mummified skin indicative of rapid desiccation after death. Bonebeds of disarticulated bones of multiple juvenile Lystrosaurus occur in shallow depressions within the rubified mudstones. Layering of different skeletal elements suggests some hydraulic sorting but the initial aggregation was likely a behavioural response to drought. Osteohistology of spread-eagled Lystrosaurus (L. declivis and L. murrayi species) skeletons show that they represent early juvenile stage which is in accordance with previous findings that throughout Pangaea Early Triassic Lystrosaurus died relatively young due to environmental stressors. Our results support the hyperthermal hypothesis that ~252 Mya increased continental aridity, already a consequence of the coalescence of Pangaea, was critically intensified by volcanogenic greenhouse gasses from the Siberian traps. We propose that in the aftermath of the End-Permian mass extinction event, a succession of climatic drying episodes orchestrated a series of fully-functioning terrestrial ecosystems that were markedly different to those of the pre-extinction, and likely had a profound and lasting influence on the evolution of tetrapods. Keywords: Early Triassic, Katberg Formation, Lystrosaurus, Drought accumulations, Bonebeds, Mummified skin Roger M.H. Smith, Jennifer Botha and Pia A. Viglietti. 2022. Taphonomy of Drought afflicted Tetrapods in the Early Triassic Karoo Basin, South Africa. Palaeogeography, Palaeoclimatology, Palaeoecology. In Press, 111207. DOI: 10.1016/j.palaeo.2022.111207 |
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