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Taxonomic data is essential to advance the discovery and description of biodiversity, as well as the study of evolutionary processes. Emerging large-scale datasets and new methods of analysis have provided different approaches to describe biodiversity. Here, we present a review of the taxonomic history in Cycadales including an analysis of historical taxonomic concepts and approaches used for species delimitation. We examine the trends in the publication of new species following taxonomic works in books, journals and horticultural catalogues, monographic projects and floras where species treatments were published. In addition, we review the studies concerning species delimitations using the literature available in scientific journals appearing in the database ISI Web of Knowledge. The approaches used were discussed throughout all research focused on empirical and theoretical considerations in each study. We review the current state of the studies on causal processes that have given rise to the currently recognized diversity. The trend shows that taxonomic work on discovery and description of species has been intensive in the last 40 years culminating in 38.8% of binomials published. As a result, we consider the relevance of the monographs and floras for identification of species for other biological disciplines and the content of these contributions is compared and discussed. A total of six criteria (diagnosability, phenetic, phylogenetic, genotypic cluster, niche specialization and coalescent) were detected from the following three approaches to species delimitation within Cycadales: traditional, integrative taxonomy, and monophyletic. In all cases, the results from these species delimitations not only provided a taxonomic treatment or proposed a new species, but also supposedly clarified the other species involved as a result of the new taxonomic concept of the new species described. Most investigations of species delimitation used the traditional approach or a phenetic criteria. Finally, we discuss evolutionary studies on causal processes involved in cycad diversity. This is considered in the context of species delimitation as hypothesis testing for a successful evaluation of variation in both genetic and morphological understanding. [ABSTRACT FROM AUTHOR]

Dalbergia emirnensis Benth. was previously treated as comprising two entities, the typical variety from the Central Highlands of Madagascar and D. emirnensis var. decaryi Bosser & R. Rabev. from the southern part of the country at lower altitudes. Additional collections and analyses demonstrate that, as currently delimited, these taxa exhibit considerable, discontinuous variability in morphology, habitat, and distribution, a finding supported by a recent phylogenomic study. We show that the material previously included in the typical variety of D. emirnensis represents two morphologically and geographically distinct entities, one that occurs only in the Central Highlands of Madagascar and includes the type specimen, and another that is morphologically and genetically more akin to D. emirnensis var. decaryi, found in the Southern Highlands of Madagascar. We describe the latter as a new species, D. nemoralis Rakoton., Phillipson & Crameri, in which we include D. emirnensis var. decaryi, recognizing it as a distinct subspecies. We also show that D. campenonii Drake should be treated as a synonym of D. emirnensis. Each of the accepted taxa is provided with a full description, a comprehensive listing of specimens examined, details of its geographic distribution and habitat, and a provisional risk of extinction assessment using the IUCN Red List categories and criteria; a line drawing is also provided for D. nemoralis subsp. nemoralis. [ABSTRACT FROM AUTHOR]

Lex Laetoria was a Roman Act from about the turn of the 3rd and 2nd centuries BC, granting additional protection to adults under the age of 25. Amongst its primary sources the Tabula Heracleensis, a.k.a. lex lulia municipalis (cf. FIRA I, 112), an excerpt from the Theodosian Code (C. Th. 8, 12, 2), and four papyri (BGUII378, BGUII 611, P. Oxy. X 1274 and P. Oxy. XVII2111) bear greater importance. These papyri are resourceful in the debate about the actual name of the Act (lex Laetoria versus lex Plaetoria). From a legal point of view, BGU II378 and P. Oxy. X 1274 contain a petition and a contract or agreement, respectively, where the reference to lex Laetoria is part of a legal argumentation. Besides the actual case, these papyri are significant because they give a presentation of the quotidian social and economic life and practice of the Roman world in Egypt around the 2nd century AD. By examining and analysing the cases described in these papyri, we get a closer view to the everyday reality of Roman law. The characters involved in the cases bear Roman names, the cases take place in Hellenised Egypt, the correspondence is in Greek, yet Roman law measures are used to settle the disputes. We sense multiculturalism in these documents, without the awkward feeling of being unfamiliar to Roman Egyptian culture. This paper aims to catch a glimpse of Roman law in action by multicultural approach, and to provide an example of how Rome had managed to handle herself as an Empire. [ABSTRACT FROM AUTHOR]

Ceratozamia (Zamiaceae, Cycadales), is a member one of the most endangered seed plant groups. Species of Ceratozamia grow from near sea level up to 2,100 meters in Mexico and Mesoamerica. We present a modern taxonomic treatment of Ceratozamia, based on fieldwork combined with detailed study of herbarium specimens in and from Mexico and Central America. This new revision is based on incorporation of morphological, molecular and biogeographic data that have been previously published in circumscriptions of species complexes by our group. Detailed morphological descriptions of the 36 species of Ceratozamia are provided and relevant characters for the genus are discussed and described. A majority are endemic to Mexico and are concentrated at high elevations in mountainous areas. Synonymies, lectotypifications, etymologies, taxonomic notes, distribution maps, illustrations and detailed species-level comparisons are included, as well as a dichotomous key for identification of all species. Data on distributional ranges and habitats of all species are summarized. Ceratozamia osbornei D.W.Stev., Mart.-Domínguez & Nic.-Mor., sp. nov. is described from evergreen tropical forests of Belize and we highlight new populations and distributional ranges for C. subroseophylla Mart.-Domínguez & Nic.-Mor. and C. vovidesii Pérez-Farr. & Iglesias in the Mesoamerican region. [ABSTRACT FROM AUTHOR]

The Stachytarpheta longispicata complex is a group of seven accepted infraspecific taxa endemic to the Brazilian Cerrado, defined by its pedicellate flowers with salmon or dark red corollas. Due to the great morphological variation and very brief original descriptions, these taxa have controversial circumscriptions. We evaluated the morphological variation through the morphometric analysis of 11 natural populations in addition to nomenclatural types to assess the current infraspecific circumscriptions and clarify the limits of these taxa. A set of 36 continuous vegetative and reproductive characters was measured for each of the 115 specimens sampled, encompassing the morphological variability in the group and its geographic distribution. A compiled data matrix formed the basis for the multivariate analysis (UPGMA, PCA, and DA). Our results recovered five consistent groups corresponding to the four subspecies, and all three recognised varieties treated in the same morphological group. Quantitative and qualitative characters not previously studied in detail are important to delimit the five groups. A taxonomic rearrangement is proposed for the complex, circumscribing five distinct species: Stachytarpheta brevibracteata, S. longipedicellata, S. longispicata, S. minasensis, and S. ratteri. The taxonomic treatment includes four new combinations and names at new rank, two new synonyms, and one lectotype. Descriptions, an identification key, geographical distribution map, illustrations, and provisional conservation assessments are also provided.

Based on recent molecular work by Paudyal & al., the generic limits of the Neotropical woody genus Exostema are reassessed with a view of making them more compatible with traditional, morphology‐based generic concepts. A wide circumscription is favoured, congruent with Paudyal & al.'s "clade B" (the Exostema‐Solenandra‐Coutarea‐Hintonia group). Thus defined, Exostema is a genus with 40 species and five natural sections and incorporates three generic splits that were proposed by Paudyal & al. To minimise nomenclatural disruption, a proposal to conserve the name Exostema Rich. against Coutarea Aubl. has been presented separately. Two new combinations at sectional rank are proposed. [ABSTRACT FROM AUTHOR]

Acanthaceae are among the most taxonomically diverse, geographically widespread, and morphologically and ecologically variable lineages of flowering plants. Most modern workers have estimated more than 4000 species and potentially more than 5000 species worldwide, thus placing Acanthaceae among the 12 or so most diverse families of angiosperms. This diversity is marked by exceptional morphological variation, particularly with respect to floral forms, growth forms, and pollen types. The present work represents a synthesis of knowledge generated over the past two decades on the taxonomy and systematics of this complex plant family. We place all 191 accepted genera within a revised classification of the family. Dichotomous keys (nine in total) to recognize the major lineages of Acanthaceae are presented together with geographically partitioned keys to all genera, covering (a) Africa, Madagascar, the Mediterranean region, and Arabia; (b) Asia and Australasia; and (c) the Americas. Finally, we validate several new tribes, subtribes, and genera, and provide new combinations for species where generic delimitation has changed. Our hope is that the present contribution serves to benefit future research on the systematics of Acanthaceae and provides a foundation upon which future classification efforts can be built. [ABSTRACT FROM AUTHOR]

This paper partially bridges a gap in the literature on Circumscription in Description Logics by investigating the tractability of conjunctive query answering in OWL2's profiles. It turns out that the data complexity of conjunctive query answering is coNP-hard in circumscribed E L and DL-lite, while in circumscribed OWL2-RL conjunctive queries retain their classical semantics. In an attempt to capture nonclassical inferences in OWL2-RL, we consider conjunctive queries with safe negation. They can detect some of the nonclassical consequences of circumscribed knowledge bases, but data complexity becomes coNP-hard. In circumscribed E L , answering queries with safe negation is undecidable. [ABSTRACT FROM AUTHOR]

Despite decades of research, we still lack a clear explanation for the emergence and persistence of inequality. Here we propose and evaluate a marginal utility of inequality hypothesis that nominates circumscription and environmental heterogeneity as independent, necessary conditions for the emergence of intragroup material inequality. After coupling the Standard Cross-Cultural Sample (SCCS) with newly generated data from remote sensing, we test predictions derived from this hypothesis using a multivariate generalized additive model that accounts for spatial and historical dependence as well as subsistence mode. Our analyses show that the probability a society will be stratified increases significantly as a function of proxies of environmental heterogeneity and environmental circumscription. This supports the hypothesis that increasing environmental heterogeneity and circumscription drives the emergence and persistence of inequality among documented societies across the globe. We demonstrate how environmental heterogeneity and circumscription produce situations that limit individuals' options so that some may find it in their best interest to give up some autonomy for material gain, while others may find it in their best interest to give up some material resources for another individual's time or deference. These results support the marginal utility of inequality framework and enable future explorations of the ecological conditions that facilitate the emergence of intragroup inequality through time and across the globe. [ABSTRACT FROM AUTHOR]

The genera Deuterocohnia, Dyckia, and Encholirium are recognized as the xeric clade Pitcairnioideae. More than 220 xeric species of this group occur in South America in the Andean region, the Chacoan subregion, and the South American Transition Zone. The species recently and rapidly diversified, and such phylogenetic relationships are difficult. This clade is well-supported in phylogenetic analyses, but despite the monophyly of this group of xeric species, the analyses have demonstrated the paraphyly or polyphyly of genera in the xeric clade. However, most of these studies suffer with partial resolution, limited taxon sampling or incorrect homology statements. To investigate this group, we conducted the most comprehensive phylogenetic analysis of the xeric clade to date using parsimony criteria with morphological and molecular datasets, including plastid and nuclear genomes concatenated for the first time, to establish a suitable classification. A total of 133 accessions were included that corresponded to 109 taxa. The dataset included 70 morphological characters and ∼6 kb of sequence data from the plastid and nuclear genomes. Phylogenetic analyses were conducted using equal and implied weighting. The analysis resulted in a well-supported cladistic hypothesis and demonstrated the three genera as currently circumscribed are not supported as monophyletic. Based on the results we propose a new classification that reflects the evolutionary relationships, a new circumscription for Dyckia is proposed that includes the species belonging to Deuterocohnia and Encholirium. For this circumscription, 41 combinations were made for Dyckia. [ABSTRACT FROM AUTHOR]

We study the complexity of the inference problem for propositional circumscription (the minimal inference problem) over arbitrary finite domains. The problem is of fundamental importance in nonmonotonic logics and commonsense reasoning. The complexity of the problem for the two-element domain has been completely classified. In this article, we classify the complexity of the problem over all conservative languages. We consider a version of the problem parameterized by a set of relations (a constraint language), from which we are allowed to build a knowledge base, and where a linear order used to compare models is a part of an input. We show that in this setting the problem is either ΠP 2P -complete, coNP-complete, or in P. The classification is based on a coNP-hardness proof for a new class of languages, an analysis of languages that do not express any member of the class, and a new general polynomial-time algorithm solving theminimal inference problem for a large class of languages. [ABSTRACT FROM AUTHOR]

The emergence of complex society is a milestone in the history of human society evolution. China is one of the few regions in the world where the earliest complex society appeared; however, its driving mechanisms remain unresolved. On the base of available evidence from both archaeology and Holocene climate, in combination with agency theory, this study attempts to address the driving mechanisms for the simultaneous emergence of complex societies in multiple areas of China around 5.5 cal ka BP. It is hypothesized that three factors, including climate change, population growth, and circumscription, jointly act and cause regional population-resource imbalance and trigger inter-group conflicts and wars. Such competitions provide the opportunity for some power-pursuing agents to break the restriction of social leveling mechanism and to become the centralized decision-making leaders, which further lead to the emergence of incipient large-scale complex societies. Increase in extreme climate events during 6.0-5.0 cal ka BP cooling period causes frequent occurrence of resource stress and increase in the frequency of inter-group competitions, which creates conditions for the legitimation, institutionalization, and persistence of centralized leadership, and finally leads to the formation of persistent institutionalized inequity. Our research result can explain not only the process and mechanism of complex society formation, but also two phenomena which cannot be reasonably explained by previous theories, that are, why the earliest complex societies in China emerge around 5.5 cal ka BP, and why they appear simultaneously in multiple regions. [ABSTRACT FROM AUTHOR]

Answer set programming (ASP) is a declarative language for nonmonotonic reasoning based on stable model semantics. A stable model is a classical model of the input program satisfying the following stability condition: only necessary information is included in the model under the assumptions provided by the model itself for the unknown knowledge in the program, where unknown knowledge is encoded by means of default negation. Rational agents acting in the real world often have to reason in presence of unknown knowledge. It is also common that real world agents cannot meet all their desiderata. For this reason, ASP programs may include weak constraints for representing numerical preferences over jointly incompatible conditions. Stable models are therefore associated with a cost given by the unsatisfied weak constraints, and stable models of minimum cost are preferred. This paper summarizes algorithms and strategies for computing optimal stable models, and hints on how these algorithms can be extended to handle some qualitative preferences that have a natural representation in circumscription, that is, those based on subset-minimality and superset-maximality. [ABSTRACT FROM AUTHOR]

Answer set programming (ASP) is a declarative language for nonmonotonic reasoning based on stable model semantics. A stable model is a classical model of the input program satisfying the following stability condition: only necessary information is included in the model under the assumptions provided by the model itself for the unknown knowledge in the program, where unknown knowledge is encoded by means of default negation. Rational agents acting in the real world often have to reason in presence of unknown knowledge. It is also common that real world agents cannot meet all their desiderata. For this reason, ASP programs may include weak constraints for representing numerical preferences over jointly incompatible conditions. Stable models are therefore associated with a cost given by the unsatisfied weak constraints, and stable models of minimum cost are preferred. This paper summarizes algorithms and strategies for computing optimal stable models, and hints on how these algorithms can be extended to handle some qualitative preferences that have a natural representation in circumscription, that is, those based on subset-minimality and superset-maximality. [ABSTRACT FROM AUTHOR]

Recent collections of Ceratozamia from the Sierra Norte of Puebla, Mexico, point to a new undescribed species, which was previously subsumed under the concept of C. mexicana. Identification of this new species resulted from a review of three associated species: C. mexicana, C. tenuis, and C. delucana. Here we describe Ceratozamia totonacorum and provide information regarding its distribution and natural history. The Ceratozamia species from the Sierra Madre Oriental, Mexico, are circumscribed using morphological characters, including a detailed evaluation of reproductive structures such as the apex, position, color and shape of the ovulate strobilus. [ABSTRACT FROM AUTHOR]

ABSTRACT Phaeostigma is a controversial taxon for its taxonomic status and phylogenetic position in the subtribe Artemisiinae, Asteraceae. To address those questions, a phylogenetic evaluation of Phaeostigma and its related genera of subtribe Artemisiinae was carried out based on molecular as well as morphological character data. DNA sequences of nuclear ribosomal DNA internal transcribed spacer, the single copy nuclear CDS gene, and five chloroplast DNA loci ( psbA-trnH, rpl16, trnC-ycf6, trnL-F, and ycf6-psbM) were used to construct gene trees, and variation patterns of 20 morphological characters were analyzed. In addition, pollen morphology was examined under scanning electron microscopy for representative species of Phaeostigma and Ajania, from which the former was separated by earlier taxonomists. All the above analyses showed: (i) Ajania tibetica (Hook.f. & Thomson) Tzvelev, A. purpurea C. Shih, and A. ramosa (Chang) C. Shih should be merged into Phaeostigma so that it is a monophyletic genus with six species, P. ramosum (A. ramosa), P. purpureum (A. purpurea), P. tibeticum (A. tibetica), P. quercifolium (W. W. Sm.) Muldashev, P. salicifolium (Mattf.) Muldashev, and P. variifolium (C. C. Chang) Muldashev; (ii) all six Phaeostigma species have the Artemisia-type (microechinate) of pollen, reflexed leaf margin, and flowering branches with sericeous indumentum; (iii) two controversial species of Ajania, A. pallasiana and A. shiwogiku, have closer relationships with Ajania s.str. than with Phaeostigma, and should be kept in Ajania. Considering all the evidence from present and previous studies, we conclude that geographic and ecological factors as well as secondary contacts play important roles in the divergence and speciation of the genus Phaeostigma. [ABSTRACT FROM AUTHOR]

Many practical problems are characterized by a preference relation over admissible solutions, where preferred solutions are minimal in some sense. For example, a preferred diagnosis usually comprises a minimal set of reasons that is sufficient to cause the observed anomaly. Alternatively, a minimal correction subset comprises a minimal set of reasons whose deletion is sufficient to eliminate the observed anomaly. Circumscription formalizes such preference relations by associating propositional theories with minimal models. The resulting enumeration problem is addressed here by means of a new algorithm taking advantage of unsatisfiable core analysis. Empirical evidence of the efficiency of the algorithm is given by comparing the performance of the resulting solver, circumscriptino, with hclasp, camus mcs, lbx and mcsls on the enumeration of minimal models for problems originating from practical applications. [ABSTRACT FROM AUTHOR]

The genus Ruellia (Acanthaceae) consists of some ca. 350 species that are concentrated in tropical and subtropical regions of the world. Old World Ruellia have never been the focus of explicit phylogenetic study, yet comprise the earliest diverging lineages in the genus and contain upwards of 100 species. We sampled 52 accessions representing 29 OW species of Ruellia for phylogenetic analysis. Results yielded five clades that were strongly supported and marked by morphological synapomorphies. Analyses additionally recovered a newly recognized lineage within the tribe Ruellieae, a small radiation of plants in the deserts of Namibia and Angola, and the name Dinteracanthus is available for reinstatement. Divergence time analysis using a primary fossil calibration revealed relatively young estimates for crown ages of all five clades of OW Ruellia (2.5 Ma - 630,000 ypb) as well as for Dinteracanthus (2.0 Ma). Ancestral state reconstruction of pollination systems among OW Ruellia suggest a minimum of two transitions from short-tongued insect pollination to nocturnal moth pollination, one from short-tongued insect to bird pollination, and one reversal from nocturnal moth pollination back to short-tongued insect pollination. We formally delimit the five clades of OW Ruellia as sections and present a key to aid in their identification: sect. Eusiphon, sect. Dipteracanthus, sect. Madagasikara, sect. Pseudoruellia, and sect. Discifolia. We provisionally treat 77 of 97 species of OW Ruellia among these five sections, with the remaining names considered to be unresolved. [ABSTRACT FROM AUTHOR]