173 research outputs found
A survey of spiders (Araneae) inhabiting the euedaphic soil stratum and the superficial underground compartment in Bulgaria
In 2005 a team of Bulgarian zoologists started a project aiming to study the invertebrates inhabiting the deeper soil stratum (euedaphon) and the Superficial Underground Compartment (SUC) in Bulgaria. In the course of a four-year sampling, a total of 52 species of spiders were caught from 19 collecting sites and 9 geographical regions. They belong to the following families: Scytodidae (1), Segestriidae (1), Dysderidae (8), Nesticidae (1), Anapidae (1), Theridiidae (1), Linyphiidae (20), Agelenidae (3), Cybaeidae (1), Dictynidae (2), Amaurobiidae (2), Liocranidae (3), Corinnidae (1), Zodariidae (1), Gnaphosidae (5), and Salticidae (1). The family Anapidae, with the species Zangherella relicta (Kratochvíl, 1935) is recorded from three sites in the Pirin and Slavyanka mountains, and this represents the first record of the family, genus and species in Bulgaria. In spite of the active investigations of the epigean and cave spiders in these regions over the years Z. relicta was not found and it seems it occurs only in deeper subterranean habitats and nowhere else. Comparative study of almost topotypic specimens of Z. relicta from Montenegro with those collected from Bulgaria showed no variation in the shape of palp and female vulvae. Until the true identity of Z. apuliae (Caporiacco, 1949) from Italy is revealed, it remains unclear whether Z. relicta and Z. apuliae are conspecific, as it remains unclear whether the older records of Z. apuliae from the Balkan Peninsula refer to this species or to Z. relicta. Pelecopsis mengei (Simon, 1884) (Linyphiidae) and Scotolathys simplex Simon, 1884 (Dictynidae) are also reported from Bulgaria for the first time, the latter being also new to FYR of Macedonia. A faunistic overview of the spiders found in these underground environments is made, along with remarks on the distribution and ecology of some rare and interesting species. The presence of cave-dwelling and superficial spiders in the sampled sites indicates that SUC and euedaphon are inhabited by different ecotypes, e.g. litter-(tanathostromic), soil-(edaphic) and cave-(troglobitic) which at some places co-occur
On the Laplace transforms of the first exit times in one-dimensional non-affine jump–diffusion models
We compute the Laplace transforms of the first exit times for certain one-dimensional jump–diffusion processes from two-sided intervals. The method of proof is based on the solutions of the associated integro-differential boundary value problems for the corresponding value functions. We consider jump–diffusion processes solving stochastic differential equations driven by Brownian motions and several independent compound Poisson processes with multi-exponential jumps. The results are illustrated on the non-affine pure jump analogues of certain mean-reverting or diverting diffusion processes which represent closed-form solutions of the appropriate stochastic differential equations
From text to structured data: Converting a word-processed floristic checklist into Darwin Core Archive format
The paper describes a pilot project to convert a conventional floristic checklist, written in a standard word processing program, into structured data in the Darwin Core Archive format. After peer-review and editorial acceptance, the final revised version of the checklist was converted into Darwin Core Archive by means of regular expressions and published thereafter in both human-readable form as traditional botanical publication and Darwin Core Archive data files. The data were published and indexed through the Global Biodiversity Information Facility (GBIF) Integrated Publishing Toolkit (IPT) and significant portions of the text of the paper were used to describe the metadata on IPT. After publication, the data will become available through the GBIF infrastructure and can be re-used on their own or collated with other data.This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.NHM Repositor
Euscorpius sicanus (Scorpiones: Euscorpiidae) from Tunisia: DNA Barcoding Confirms Ancient Disjunctions Across the Mediterranean Sea
We used a DNA barcoding marker (mitochondrial cox1) to investigate the controversial natural occurrence of Euscorpius sicanus (C.L. Koch) in North Africa. We tested this hypothesis by comparing a sample collected from a mountain in Tunisia to disjunct populations in Sardinia, Malta, and Greece. Using these samples, and a few additional Euscorpius spp. from southern Europe as outgroups, we reconstructed the maternal phylogeny. We then used a molecular clock to place the phylogeny in a temporal context. The Tunisian sample grouped closest to a specimen from Sardinia, with both being more distantly related to E. sicanus from Malta, which is known to be genetically similar to samples from Sicily. Molecular clock estimates suggest an ancient disjunction across the Mediterranean Sea, with the divergence between samples from Sardinia and Tunisia estimated to have occurred between the Late Miocene and late Pliocene. The divergence date (mean = 5.56 Mya) closely corresponds with the timing of a sudden refilling of the Mediterranean Sea after it had evaporated during the Messinian salinity crisis. This rapid influx of water, in conjunction with tectonic activity, could have sundered connections between Euscorpius in North Africa and what is now the island of Sardinia. These results provide yet another case in which DNA barcodes have proven useful for more than just identifying and discovering species
A revision of the millipede family Paracortinidae (Diplopoda, Callipodida)
The taxonomy of the family Paracortinidae Wang & Zhang, 1993 is revised based on literature, old and recently collected material. A new genus Crassipetalum Akkari & Stoev, gen. nov. is described, to accommodate a new species Crassipetalum magnum Akkari & Stoev, gen. nov. et sp. nov. and a recently described species Crassipetalum inflatum (Chen, Zheng & Jian, 2023), comb. nov. The genus Scotopetalum Shear, 2000 hitherto described for the Vietnamese species S. warreni Shear, 2000 and subsequently synonymised with the genus Paracortina Wang & Zhang, 1993 is here resurrected and supplemented with another species, S. chinensis (Stoev & Geoffroy, 2004), comb. nov., ex Paracortina chinensis Stoev & Geoffroy, 2004. The status of the fourth genus in the family, Angulifemur Zhang, 1997, is reconfirmed. Based on recently collected specimens from China, two new species of the genus Paracortina are described: P. asciformis Akkari & Stoev, sp. nov. (Sichuan Prov., Lixian County) and P. kabaki Akkari & Stoev, sp. nov. (Yunnan, Shangrila County). The Vietnamese species Paracortina multisegmentata Stoev & Geoffroy, 2004 and Paracortina kyrang Nguyen, Stoev, Nguyen & Vu, 2023 are considered of uncertain taxonomic position within Paracortinidae. Differential diagnoses for the proposed genera as well as for all the species are presented, and descriptions or descriptive notes for all the species are provided, using a standardised terminology, and when possible, accompanied by micrographs of the habitus and gonopod structures. An identification key based on gonopod structures is proposed for all the members of the family. A discussion on species affinities, secondary sexual characters, troglomorphic characters, geographical distribution, and habitat preferences are also provided together with a distribution map for all members of the family
On the sequential testing and quickest change-pointdetection problems for Gaussian processes
We study the sequential hypothesis testing and quickest change-point (disorder) detec- tion problems with linear delay penalty costs for certain observable time-inhomogeneous Gaussian diffusions and fractional Brownian motions. The method of proof consists of the reduction of the initial problems into the associated optimal stopping problems for one- dimensional time-inhomogeneous diffusion processes and the analysis of the associated free boundary problems for partial differential operators. We derive explicit estimates for the Bayesian risk functions and optimal stopping boundaries for the associated weighted likelihood ratios and obtain their exact asymptotic growth rates under large time values
On the construction of non-affine jump-diffusion models
We describe a method for construction of jump analogues of certain one-dimensional diffusion processes satisfying solvable stochastic differential equations. The method is based on the reduction of the original stochastic differential equations to the ones with linear diffusion coefficients, which are reducible to the associated ordinary differential equations, by using the appropriate integrating factor processes. The analogues are constructed by means of adding the jump components linearly into the reduced stochastic differential equations. We illustrate the method by constructing jump analogues of several diffusion processes and expand the notion of market price of risk to the resulting non-affine jump-diffusion models
A redescription of the poorly known cave millipede Skleroprotopus membranipedalis Zhang, 1985 (Diplopoda, Julida, Mongoliulidae), with an overview of the genus Skleroprotopus Attems, 1901
We redescribe the poorly known Chinese millipede Skleroprotopus membranipedalis Zhang, 1985 recorded from Shi-Hua (Stone Flower) Cave, Fangshan County, Beijing. The species’ original description is in Chinese in an obscure outlet which significantly hampers its recognition from its congeners. Here, based on newly collected material, we provide the first scanning electron micrographs of important taxonomic traits. In addition to its type locality, we report the species also from Yun-Shui (Cloud Water) Cave, situated in the same county, some 18 km away. We propose the genus Senbutudoiulus Miyosi, 1957 to be a junior subjective synonym of Skleroprotopus Attems, 1901, syn. n., and introduce the following new combination: Skleroprotopus platypodus (Miyosi, 1957), comb. n. (former Senbutudoiulus)
A rapid multi-disciplinary biodiversity assessment of the Kamdebooberge (Sneeuberg, Eastern Cape, South Africa): implications for conservation
Botanical work since 2008 on the Sleeping Giant section of the Kamdebooberge (Sneeuberg mountain complex, Eastern Cape, South Africa) has indicated that these mountains may be of significant conservation value. Accordingly, a precursory, rapid multi-disciplinary biodiversity assessment was undertaken in January 2011, focusing on plants, tetrapod vertebrates and leafhoppers. The botanical results confirm the Kamdebooberge as being of high botanical conservation value, hosting three strict endemics, healthy populations of five other Sneeuberg endemics, and fynbos communities comprising species not found elsewhere in the Sneeuberg. The Kamdebooberge are important for herpetofauna (excluding serpentoids) and mammals, hosting several range-restricted and regional endemics. The expedition uncovered three new leafhopper species, together with several species previously only known from the Cape Floristic Region. Further detailed faunal work may provide further interesting results from these mountains, which show a high conservation value unique to the southern Escarpment
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