Maria João Fernandes Martins

Universidade do Algarve | UALG · Interdisciplinary Center for Archaeology and Evolution of Human Behaviour

The study of past environmental changes allows us to better know the landscapes where humans lived, as well as the drivers of landscape evolution. This is particularly important for the Inhambane coast (Southeastern Mozambique) because the area has great archaeological potential. To study the Inhambane coast’s paleoenvironmental changes, two sedime...

Southeastern Mozambique, in particular the Inhambane coastal region, is rich in suitable environments for human settlement and has great archaeological potential. However, knowledge about past environmental changes and human-environment relationships in this area is still scarce. Thus, in the InMoz project, we aimed to better understand the Inhamba...

Background The ‘genetic diversity’ hypothesis posits that polyandry evolved as a mechanism to increase genetic diversity within broods. One extension of this hypothesis is the ‘genetic diversity for disease resistance’ hypothesis (GDDRH). Originally designed for eusocial Hymenoptera, GDDRH states that polyandry will evolve as an effect of lower par...

Ostracods are ubiquitous bivalved aquatic micro-crustaceans with a rich fossil record. Despite their potential in revealing critical transitions in lake ecosystems related to past climatic changes and anthropogenic impacts, ostracod-based studies remain rare for this region. We present ca. 7,300 calibrated years before the present (cal BP) of limno...

Ostracodes of the superfamily Cytheroidea exhibit sexual dimorphism in the carapace such that males are more elongate than females. This sex difference is attributed to the need of the carapace to accommodate the large male copulatory apparatus, and the degree of dimorphism is an indication of male investment in reproduction. In this study, we exam...

The southeastern coast of Mozambique is a key area for the development of paleoenvironmental and human evolution studies. To understand the history of environmental evolution in this area, two cores were collected in the Muangue and Nyalonzelwe lakes. The cores were analyzed for their sediment texture, content of organic/inorganic carbon and nitrog...

Understanding the role of climate on the onset of behavioral modernity in anatomically modern humans has never been more vital in the quest to reconstruct our origins. In order to understand the role climate played in facilitating the development and expression of modern human behaviors, our interdisciplinary research team cored a series of coastal...

Sexual selection often favours investment in expensive sexual traits that help individuals compete for mates. In a rapidly changing environment, however, allocation of resources to traits related to reproduction at the expense of those related to survival may elevate extinction risk. Empirical testing of this hypothesis in the fossil record, where...

In order to better quantify the role of climate variability in southeastern Africa, and its impact on the evolution and spread of anatomically modern humans, our international and interdisciplinary team cored a series of coastal lakes during the summer of 2019. Here, we present data from lake Nyalonzelwe, one of many interdunal lakes present along...

Esta aula pretende apresentar o Projeto InMoz e a sua equipa. Este projeto tem como objetivo investigar as alterações ambientais ao longo do Quaternário na área Sudeste de Moçambique e os seus impactos na evolução humana. Assim, foi feita uma introdução sobre o que são paleoambientes e que fatores influenciam a sua evolução (e.g. alterações climáti...

The Ostracoda – ubiquitous aquatic micro-crustaceans – show an exceptionally high incidence of female-biased adult sex ratio. Intraspecific sex ratio is known to vary in extant species and yet in the fossil record a species’ adult sex ratio can be highly stable across time. Sex ratio conditions the intensity of sexual selection and influences which...

Sexual selection favours traits that confer advantages in the competition for mates. In many cases, such traits are costly to produce and maintain, because the costs help to enforce the honesty of these signals and cues 1 . Some evolutionary models predict that sexual selection also produces costs at the population level, which could limit the abil...

Sexual dimorphism is common in many extant animals, but it is difficult to demonstrate in fossil species. Working with material from the Late Cretaceous of the U.S. Coastal Plain, we herein analyze sexual dimorphism in ostracodes from the superfamily Cytheroidea, a group whose extant members have males that are relatively more elongate than females...

Assessing the long-term macroevolutionary consequences of sexual selection has been hampered by the difficulty of studying this process in the fossil record. Cytheroid ostracodes offer an excellent system to explore sexual selection in the fossil record because their readily fossilized carapaces are sexually dimorphic. Specifically, males are relat...

Directional asymmetry estimates with respect to sample size. Asymmetry was computed on a percent scale, 100*[L-R]/L. Limbs are plotted according to their abbreviations in Table 3; colors indicate species (black = C. mexicana, red = C. salebrosa, green = C. torosa) and fonts indicate sex (bold = female, italics = male). (TIFF)

Raw measurements from valves, sexual and non-sexual limbs. (XLSX)

Mean (m, in μm), directional asymmetry (L-R), coefficient of variation (CV) and sample size (N) of the remaining variables analyzed representing size in the hemipenis basal capsule section (HemiBC 1-2L, Hemi 3–4 L). (DOCX)

Sample information and number of individuals (N) used in morphometric analyses. *All samples within species were pooled for analysis. Latitude and longitudes are approximate for C. mexicana. (DOCX)

Video of Cyprideis torosa in laboratory. (ZIP)

Geographical parthenogenesis – in which parthenogenetic populations are more widely distributed than sexually reproducing populations – is observed in many plant and animal species. Many hypotheses have been proposed to account for this biogeographical pattern, and these often invoke historical processes such as the influence of glaciation. However...

Background The fucoid brown algae (Heterokontophyta, Phaeophyceae) are increasingly the focus of ecological genetics, biodiversity, biogeography and speciation research. The molecular genetics underlying mating system variation, where repeated dioecious – hermaphrodite switches during evolution are recognized, and the molecular evolution of sex-rel...

The distribution pattern of the freshwater ostracod Eucypris virens shows geographic parthenogenesis: sexual populations are restricted to the Mediterranean area, whereas parthenogens extend much wider toward Northern Europe. By means of an extensive sampling campaign - from Estonia to Morocco and from Portugal to Turkey - we analysed the associati...

Ongoing stratigraphical study at the Serra do Bouro region (Caldas da Rainha) allows mentioning, for the first time in this area, occurrence of the Cabaços Formation (Oxfordian) at outcrop. In spite of the small dimension of the section and the local tectonism, field characterization and sampling of several levels (some discontinuous) was possible:...

Environmental stress imposes strong natural selection on clonal populations, promoting evolutionary change in clonal structure. Environmental stress may also lead to reduction in population size, which together with clonal selection may reduce genotypic diversity of the local populations. We examined how clonal structure in wild-collected samples o...

Ostracods have a ubiquitous distribution, a high diversity of life history strategies and an extensive fossil record. These characteristics make the group a useful study tool in multiple disciplines. In Portugal, very few studies on recent freshwater ostracods have been published. This is particularly important given the need for an accurate databa...

Palavras-chave: Formação de Cabaços; microfácies; ostracodos; Serra do Bouro; Bacia Lusitânica. Resumo: Estudo estratigráfico recente na região da Serra do Bouro (Caldas da Rainha) permitiu reconhecer pela primeira vez em afloramento, nesta zona, a Formação de Cabaços (Oxfordiano). Apesar da restrita dimensão do corte e da tectonização local, foi p...

Eucyprisvirens is a freshwater ostracod in which both sexual reproduction and parthenogenesis occur. Sympatric coexistence of both reproductive modes is known in zones of overlap. This renders the species a potentially valuable model organism to study the ‘queen of evolutionary problems’, i.e. why sex is so successful despite its costs (paradox of...

Transitions from sexual to asexual reproduction are often coupled with elevations in ploidy. As a consequence, the importance of ploidy per se for the maintenance and spread of asexual populations is unclear. To examine the effects of ploidy and asexual reproduction as independent determinants of the success of asexual lineages, we sampled diploid...

The persistence of asexual reproduction in many taxa depends on a balance between the origin of new asexual lineages and the extinction of old ones. This turnover determines the diversity of extant asexual populations and so influences the interaction between sexual and asexual modes of reproduction. Species with mixed reproduction, like the freshw...

The present study examined sex ratios in five lacustrine profundal species displaying sexual dimorphism in the shape and/or size of the carapace valves: Limnocytherina sanctipatricii, Leucocythere mirabilis, Candona neglecta, Fabaeformiscandona levanderi and Fabaeformiscandona protzi. Data derived from a survey of sub-fossil ostracod valves preserv...

In many species with mixed reproduction, parthenogens cover a wider geographic range than sexuals. In freshwater ostracods this pattern referred to as geographic parthenogenesis is traditionally explained by ascribing a higher potential for dispersal to parthenogens. For example, the postglacial invasion hypothesis states that the lack of males in...