Patrick J. Lewis

Faunal assemblage composition and paleoenvironment of Plovers Lake, a Middle Stone Age locality in Gauteng Province, South Africa

Plovers Lake is a dolomitic cave infill located approximately 45km northwest of Johannesburg in the Bloubank Valley, Gauteng Province, South Africa. Excavations between 2002-2004 revealed a rich and diverse fauna, a moderate-sized stone tool assemblage of Middle Stone Age (MSA) character, and human skeletal remains. Two principal depositional units are recognized: 1) a disturbed ex situ component that was likely displaced from 2) an otherwise relatively undisturbed in situ component from which the human skeletal material was recovered. The in situ depositional unit is bracketed by 2 flowstone layers, with U-series dates of 62.9 (+/-1.3)ka for the capping flowstone and 88.7 (+/-1.6)ka for the underlying flowstone. A single isochron ESR date of 75.6 (+/-5.6)ka corroborates the U-series dates. This paper presents an analysis of the mammalian, bird, and reptile faunas recovered from these two units. The two faunal assemblages show close correspondence in taphonomic, taxonomic, and ecological composition, supporting a common origin for both the ex situ and in situ components. Although human skeletal material, cut-marked bone, and stone tools have been recovered, these indications are too rare to consider Plovers Lake a human occupation site. Instead, a high abundance of carnivores, coprolites, and carnivore damaged bones point to brown hyenas as the principal, though not exclusive, bone accumulating agent. In the absence of a significant taphonomic bias relating to accumulating agent, Plovers Lake allows us to document an environment occupied by MSA humans, even if the humans were not resident in the cave itself. We reconstruct the paleoenvironment of Plovers Lake as predominantly grassland, though it was colder, moister, and more wooded than at present. Paleoclimatic conditions appear to have been as different from historic norms as those seen in several fossil localities in the Western Cape, pointing to greater environmental heterogeneity than has previously been documented for the region in the later Pleistocene.

A Morphometric Approach to Assessing Late Paleoindian Projectile Point Variability on the Southern High Plains

Abstract Late Paleoindian typology on the southern High Plains has suffered from overlapping definitions and subjectivity in assigning individual projectile points to types. To address perceived projectile point variability in the region, assemblages from several localities on the southern High Plains are examined for statistical differences in shape. Digital photographs of projectile points are used to digitize point outlines. Landmark coordinate data then are used to delineate 10 interlandmark characters. Multivariate analysis of projectile points from eight assemblages reveals that the primary difference in point shape lies between long points with narrow bases and short points with wide bases. Analysis of characters by raw material type or source discerned no significant differences. Variation in point form represented by most of the assemblages, including the Plainview and Milnesand type assemblages, overlaps to a significant degree. The Lubbock Lake FA5-17 assemblage, consisting of long points with narrow bases, appears most distinct in terms of shape and raw material selection indicating the contemporaneity of different point forms and perhaps technological traditions in the region by approximately 10,000 years ago.

Mitochondrial DNA and karyotypic data confirm the presence of Mus indutus and Mus minutoides (Mammalia, Rodentia, Muridae, Nannomys) in Botswana

Abstract We use a combination of cytochrome b sequence data and karyological evidence to confirm the presence of Mus indutus and Mus minutoides in Botswana. Our data include sampling from five localities from across the country, including one site in northwestern Botswana where both species were captured in syntopy. Additionally, we find evidence for two mitochondrial lineages of M. minutoides in northwestern Botswana that differ by 5% in sequence variation. Also, we report that M. minutoides in Botswana have the 2n=34 karyotype with the presence of a (X.1) sex-autosome translocation.

Peramorphic Traits in the Tokay Gecko Skull

Traditionally, geckos have been conceived to exhibit paedomorphic features relative to other lizards (e.g., large eyes, less extensively ossified skulls, and amphicoelous and notochordal vertebrae). In contrast, peramorphosis has not been considered an important process in shaping their morphology. Here, we studied different sized specimens of Gekko gecko to document ontogenetic changes in cranial anatomy, especially near maturity. Comparison of this species with available descriptions of other geckos resulted in the identification of 14 cranial characteristics that are expressed more strongly with size increase. These characteristics become move evident in later stages of post‐hatching development, especially near maturation, and are, therefore, attributed to peramorphosis (hyperossification). ACCTRAN and DELTRAN character optimizations were applied to these characters using a tree of 11 genera derived from a gekkotan molecular phylogeny. This analysis revealed that G. gecko expresses the majority of these putative peramorphic features near maturity, and that some of these features are also expressed in species closely related to G. gecko. The characters studied have the potential to be applied in future phylogenetic and taxonomic studies of this group of lizards. J. Morphol. 276:915–928, 2015.

The Homology of the Pelvic Elements of Zygaspis quadrifrons (Squamata: Amphisbaenia)

Limb attenuation with element loss has occurred multiple times among the Squamata (lizards, snakes, and amphisbaenians). Although most of the attention has been focused on the appendicular bones, we found that the pelvic rudiments have been studied less thoroughly and recurring disagreement is common among different authors studying the same species. We studied the osteology of the pelvic region of female and male Zygaspis quadrifrons with high‐resolution X‐ray computed tomography data. We report an osteological landmark (acetabulum) not previously detected in this taxon, the presence of which has repercussions that call for a reconsideration of the primary homology hypothesis for the identity of these bones in amphisbaenians and other squamates. Finally, we observed that the acetabulum and limb rudiments in amphisbaenians (i.e., the stylopodium when present) are situated medial to the pelvic girdle, contrasting with the large majority of tetrapods where these structures are laterally oriented. Anat Rec, 297:1407–1413, 2014.

A comparison of factors affecting the small-scale distribution of mercury from artisanal small-scale gold mining in a Zimbabwean stream system

Artisanal small-scale gold mining (ASGM) operations use mercury liberally in the gold extraction process and account for approximately one quarter of the anthropogenic mercury consumption worldwide. ASGM activities are concentrated in many impoverished and poorly regulated countries such as Zimbabwe, resulting in a number of negative impacts to health and the environment. To examine levels of mercury contamination in one such geographic locality, sediment and tailing samples were collected in a heavily mined watershed in southern Zimbabwe from May-June 2015. Samples were collected from multiple points within the stream system, as well as from around six stamp mills and a single industrial mine in the watershed. GPS point location data were taken for mining operations and sampling sites to examine the spatial patterns of mercury concentration. Data were first analyzed using linear regression and development of a MARS model, followed by application of an ANCOVA model to assess the relationship among mercury concentrations and percent organic material, distance downstream, and distance from potential contamination source. Mercury concentrations within the study area ranged from 6 to 1541 μg/kg dw (mean 142 μg/kg dw). Analyses of mercury concentrations indicated a positive relationship with percent organic material but a negative relationship with distance downstream and distance from potential contamination source. Results from this study help elucidate the relationship between gold production and the spatial scale of mercury contamination in aquatic ecosystems in Africa. These data may lead to a better understanding of the relationship between mercury use and community health, which may aid both the local and global communities in regulating mercury contamination of the environment.

Effect of fire on the herpetofauna of the Koanaka Hills, Ngamiland, Botswana

Ngamiland is one of the most remote regions in Botswana, and its herpetofauna is largely under-surveyed. This study documents the herpetofauna of the Koanaka Hills (KH) in Ngamiland in 2009 following extensive fire destruction and compares it to the pre-fire herpetofauna collected in 2008. We also provide new records for the region for three amphibian and six reptile species, and document vouchers for two taxa that were sighted but not collected in 2008. During 2009, 14 reptile and three amphibian species were collected, bringing the total number of confirmed herpetofaunal taxa near the KH to three amphibian and 19 reptile species. For seven species this is the first published occurrence in quarter degree square 2021 Aa. Analyses measuring changes in the KH herpetofauna following the fire are inconclusive due to differences in collection effort and weather conditions. However, these data suggest that fire impact was minimal.

The Plainview Bone Bed – New Insights from an Old Collection

ABSTRACT Plainview is a Paleoindian bison kill on the Southern High Plains (USA). This study examines whether the Plainview bison represent a chronologic marker, tests three models regarding the season of kill(s), and explores site size and number of kill events. Size difference in early Holocene southern grasslands bison is a matter of biogeographic variation of the same species rather than reflecting a time difference. None of the three models adequately addresses the season of kill or number of kills. A fourth model is posited based on a combination of the three, with kills taking place in spring, summer, and fall. The location of Creel’s bone bed is defined; this second bone bed indicates at least two major kills took place at the site Site purpose for summer kills may have been to support large group social activities. Plainview, larger and more complex than originally thought, is expanded to ∼1.3 hectares and is a persistent place on the landscape.

The first record of Wormian bones in lizards

ABSTRACT Wormian bones are accessory bones found between cranial elements. These rare bones vary greatly in size, shape and placement. Wormian bones are well-known in mammals, notably in humans and chimpanzees, but not in lizards. Here we examine the genus Zygaspis, a southern African amphisbaenian with complex cranial sutures, for the presence of Wormian bones. Skulls from seven of the eight species of Zygaspis were examined for the presence of Wormian bones. Because of their small size, complex sutures and delicate nature, high-resolution X-ray computed tomography was used to produce 3D models of the skulls. We discovered three Wormian bones in the interdigitated frontoparietal suture of Z. kafuensis. This discovery is the first known record of Wormian bones in a lizard and it is one of the few reports of them in the Squamata. The presence of Wormian bones in a head-first, burrowing squamate allows for a possible functional role to be hypothesised. Additional studies on a variety of squamate taxa are now needed, particularly in burrowing groups with interdigitated sutures, to improve our understanding of these rare cranial elements.

A Geographic Information Systems (GIS)-based analysis of modern South African rodent distributions, habitat use, and environmental tolerances

Goals of this study were to: (1) develop distributional maps of modern rodent genera throughout the countries of South Africa, Lesotho, and Swaziland by georeferencing museum specimens; (2) assess habitat preferences for genera by cross-referencing locality position with South African vegetation; and (3) identify mean annual precipitation and temperature range where the genera are located. Conterminous South Africa including the countries of Lesotho and Swaziland Digital databases of rodent museum specimens housed in the Ditsong National Museum of Natural History, South Africa (DM), and the Division of Mammals, National Museum of Natural History, Smithsonian Institution, United States (NMNH), were acquired and then sorted into a subset of specimens with associated coordinate data. The coordinate data were then used to develop distributional maps for the rodent genera present within the study area. Percent habitat occupation and descriptive statistics for six climatic variables were then determined for each genus by cross-referencing locality positions with vegetation and climatic maps. This report presents a series of maps illustrating the distribution of 35 rodent genera based on 19,471 geo-referenced specimens obtained from two major collections. Inferred habitat use by taxon is provided for both locality and specimen percent occurrence at three hierarchical habitat levels: biome, bioregion, and vegetation unit. Descriptive statistics for six climatic variables are also provided for each genus based on locality and specimen percent incidence. As rodent faunas are commonly used in paleoenvironmental reconstructions, an accurate assessment of rodent environmental tolerance ranges is necessary before confidence can be placed in an actualistic model. While the data presented here represent only a subset of the modern geographic distributions for many of the taxa examined, a wide range of environmental regimes are observed, suggesting that more research is necessary in order to accurately reconstruct an environmental signature when these taxa are found in the fossil record.