No abstract

Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document.When citing, please reference the published version. Take down policyWhile the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

Continuing palaeofloristic studies in the Northern Tocantins Fossil Forest, we describe two new calamitalean species from the Permian of the Parnaíba Basin (central-north Brazil). The fossils comprise axes of various sizes, preserved anatomically as siliceous petrifactions, and found in highly mature sandy fluvial deposits of the Motuca Formation. Based on anatomical and morphological characteristics, Arthropitys tocantinensis sp. nov. and Arthropitys barthelii sp. nov. are described. They share a small central pith cavity (extremely reduced in the latter), scalariform tracheid pitting, and prominent pitting of the ray parenchyma. However, they differ markedly in their branching system: the former having 3-12 branches per node either with or lacking secondary growth, the latter showing 2-17 branches without any secondary growth. However, in A. tocantinensis sp. nov., the presence of large woody branches supports a more complex architecture with at least three successive orders of branches. The extensive secondary tissue in both species is homogeneous; clear segmentation is only visible in the proximal wood of A. tocantinensis sp. nov., but completely absent in A. barthelii sp. nov. The growth architecture of these upright growing, self-supporting trunks are reconstructed based on sizable transverse and longitudinal preparations. Our results confirm that thick woody calamitaleans were elements of disturbed riparian vegetation and much more diverse in terms of anatomy and branching patterns than previously thought. They were well adapted to seasonally dry conditions and formed major plant constituents of Permian low-latitude Southern Hemisphere communities. Additionally, we report the first evidence of colonisation on arborescent calamitaleans by herbaceous sphenophyte axes from the Permian. One of the Arthropitys stems hosts at least 30 Sphenophyllum shoots of various ontogenetic stages, growing inside the destroyed pith, which was previously excavated by arthropod boring. Based on the distribution of key genera within late Paleozoic floras of Euramerica, Gondwana and Cathaysia floral realms cluster analysis and Jaccard Coefficient highlight the distribution of a "Mid-North Brazilian" phytogeographic Region during the early Permian.

Although Permian fossils have been known from the Parnaíba Basin for two centuries, and some faunal and flora elements are well known worldwide, research on the fossil assemblages from this basin has lagged relative to other, more accessible basins. In the last decade, however, there has been a significant increase in the study of fossils from the two Permian units of the basin: the Pedra de Fogo and Motuca formations. The goal of this contribution is to synthesize and update the existing data on the Permian macrofossils from these formations, and to use them to address biostratigraphic, palaeoenvironmental and palaeogeographical questions. The Pedra de Fogo and Motuca formations are likely to be Cisuralian in age. Contrary to previous reports, there is more than one stratigraphic interval that preserves petrified fossil plants. The possible marine influence proposed for the Pedra de Fogo Formation must be reassessed based on the strongly terrestrial character of its fossil assemblages. Palaeoenvironmental and palaeoclimatic conditions are inferred to be wetter than is typically predicted for this region of the globe based on climatic modelling. Despite sharing some taxa with the Euramerican and Gondwanan biogeographical provinces, the Parnaíba Basin was likely to have been part of a distinct biogeographical province, as indicated by the high degree of endemism displayed by its Permian floras and faunas.

The Pennsylvanian-Permian interval of the Paraná Basin is relatively well-known on its palynological content. However, little has been published from the Permian Serra Alta, Teresina and lower Rio do Rasto formations (Passa Dois Group). A total of thirty seven core samples were collected along a vertical range of 600 meters of these units in two boreholes in the Congonhinhas Municipality, northeastern Paraná State, South Brazil, but only the Teresina Formation and the lower part of the Serrinha Member of the Rio do Rasto Formation yielded identifiable palynomorphs. Of the thirty recorded species, ten species are registered for the first time in the basin, three are probably new, and five were previously documented at stratigraphic levels below the units of the present study. Assemblages are assigned to the Lueckisporites virkkiae Zone, regarded as Middle Permian (Guadalupian) in age, as suggested by other fossil and radiometric data. According to the relative abundance of some spore species, it is possible to discriminate two intervals: the first characterized by the predominance of Laevigatosporites vulgaris (from the Teresina Formation to the basal Serrinha Member), and the second dominated by Thymospora (in higher stratigraphic levels). The great abundance of fern spores in these assemblages is amazing because lycophyte stems are the best represented macrophytofossils of the Teresina Formation, similarly as glossopterid leaves and sphenophyte stems in the Rio do Rasto Formation. These aspects are discussed in the scope of lithofaciological and other paleontological data.

SURVIVORSHIP CURVE AND ESTIMATE OF ENTROPY IN LUCILIA CUPRINA (DIPTERA, CALLIPHORIDAE). Lucilia cuprina (Wiedemann, 1830) is a cosmopolite blowfly species of medical and veterinary importance because it produces myiasis, mainly in ovine. In order to evaluate the demographic characteristics of this species, survivorship curves for 327 adult males and 323 adult females, from generation F 1 maintained under experimental conditions, were obtained. Entropy was utilized as the estimator of the survival pattern to quantify the mortality distribution of individuals as a function of age. The entropy values 0.216 (males) and 0.303 (females) were obtained. These results denote that, considering the survivorship interval until the death of the last individual for each sex, the males present a tendency of mortality in more advanced age intervals, in comparison with the females.

One of the youngest known occurrences of anatomically preserved Sphenophyllum Brongniart 1828 is reported from the Permian Motuca Formation, Parnaíba Basin, centralnorth Brazil. At least 31 stems, densely interwoven to each other and associated with tiny roots and leaves of this extinct herbaceous sphenopsid, were found in a silica-petrified state. Originally grown upright, they squeezed into in the pith of the arborescent calamite Arthropitys barthelii NEREGATO et al. 2017, which was additionally caved by putative xylophagous herbivores. Although restricted within natural limits, the Sphenophyllum organs show different developmental stages that encompass a majority of juvenile stems and a few ones with initial secondary growth. The stems are of circular to elliptical outline and consist of a central triarch actinostele made of primary vascular tissues and a variable amount of wood. Extraxylary tissues comprise a narrow innermost zone with putative phloem, internal periderm made of rectangular cells arranged in radial files, inner parenchymatous cortex, outer sclerenchymatous cortex, and small-celled layers of bounding tissue. Moreover, Sphenophyllum is exhibited to be a frequent climber on the trunk surface of Psaronius, Tietea and Grammatopteris tree ferns or trapped among their adventitious aerial roots. In addition, Sphenophyllum cauline members were also found dispersed with other plant organs in a particular type of fossil-rich silicified fluvial sandstone or chert reflecting rapid fossilisation of parautochthonous aspects. These fossil assemblages disclose an underestimated facet of seasonally influenced, densely vegetated riparian forests bordering extended distal fluvial discharges in low-latitude Gondwana. Nevertheless, due to their similar development of major anatomical characteristics, the taxonomic delimitation of late Paleozoic sphenophylls based on vegetative axes alone remains challenging and underlines unexpected long-term stability of especially primary cauline anatomy and vascular architecture in general.

No abstract