A molecular and conchological dissection of the "scaly" <i>Georissa</i> of Malaysian Borneo (Gastropoda, Neritimorpha, Hydrocenidae)

The Bornean hydrocenids have so far been understudied compared to other non-pulmonate snails in this region. In the present study, we review a first group of minute land snail species belonging to the genus Georissa (Gastropoda, Hydrocenidae) from Malaysian Borneo. This group is restricted to the species with conspicuous scale-like sculpture on the shell. Based on materials from recent fieldwork, museums, and personal collections, Malaysian Borneo hydrocenids are more complex and diverse in shell characters than previously anticipated. Here, a molecular, conchological, and biogeographic study of this "scaly group" is presented. We recognise 13 species of which six are new to science, namely Georissa anyiensis sp. n., Georissa muluensis sp. n., Georissa bauensis sp. n., Georissa silaburensis sp. n., Georissa kinabatanganensis sp. n., and Georissa sepulutensis sp. n

Analyzing Risk and Performance Using the Multi-Factor Concept

In this paper, we present a new model to analyze the risk and the expected level of firm performance. This model is based on the multi-factor approach to risk, in which unexpected performance is explained through sensitivities to unexpected changes of risk factors. Instead of using the multi-factor approach for the analysis of security portfolios, it is used to analyze performance measures of firms. In this paper the multi-factor approach is not only used to analyze risk, but also to analyze the expected level of performance. Furthermore, it is analyzed how instruments, as for instance projects, can be used to change the risk and the expected level of performance. An illustrative application in the field of finance is presented, although the model can also be applied in other areas

Conchological and molecular analysis of the "non-scaly" Bornean <i>Georissa</i> with descriptions of three new species (Gastropoda, Neritimorpha, Hydrocenidae)

The Bornean representatives of the genus Georissa (Hydrocenidae) have small, dextral, conical, calcareous shells consisting of ca. three teleoconch whorls. Our recent study on the Georissa of Malaysian Borneo has revealed high intra- and inter-specific variation in the "scaly" group (a group of species with striking scale-like surface sculpture). The present study on the "non-scaly" Georissa is the continuation of the species revision for the genus. The "non-scaly" species are also diverse in shell sculptures. This informal group comprises Georissa with subtle spiral and/or radial sculpture. The combination of detailed conchological usessment and molecular analyses provides clear distinctions for each of the species. Conchological, molecular, and biogeographic details are presented for 16 species of "non-scaly" Georissa. Three of these are new to science, namely Georissa corrugata sp. n., Georissa insulae sp. n., and Georissa trusmadi sp. n.</p

TWO NEW SPECIES OF DIPLOMMATINA BENSON, 1849 (GASTROPODA, CAENOGASTROPODA: DIPLOMMATINIDAE) FROM BORNEO

Two new species of Diplommatina from limestone hills on Borneo are described: D. heteropleura sp. nov., from Sarawak (Malaysia) and D. stenoacron sp. nov., from East Kalimantan (Indonesia). The first is uniquely identified among the Bornean Diplommatina by the arrangement of radial ribs: widely spaced on all whorls except the last 1.5, where they are closely spaced; the second belongs to a small group of species without radial ribs but is larger than any of them

Susceptibility of tropical mountain forests to biological invasions from the temperate and subtropical zone, exemplified by <i>Zonitoides</i> (Gastropoda: Gastrodontidae)

Colonisation by, and spread of, animal species from the temperate zone are rather uncommon observations in the tropics. The study provides the first reports of two snail species of the genus Zonitoides in Sabah, Borneo, namely Z. arboreus (Say, 1819) and Z. nitidus (O.F. Muller, 1774). The identification was aided using partial sequences of 28S rDNA, and the barcoding sequence of COI. So far, the two Zonitoides species were found in locations where the natural forest cover had been disturbed, and only in the montane forest at elevations between 1500 and 2000 m a.s.l.. Niche modeling suggests that both taxa could be widely distributed in the mountains of tropical South America and Africa. Z. arboreus finds suitable climates in many places in SE Asia and especially at many conservation areas in Borneo. In contrast, Z. nitidus finds only marginal climatic conditions in the same area, and introductions of Z. nitidus probably will remain spatially restricted. This prediction, however, needs to be monitored because the latter species can display molluscivory. Our results additionally point to the possibility of Z. arboreus being a species complex that, given its potential economic impact, urgently needs a taxonomic revision.</p

New Diplommatinidae from Sarawak, Malaysia (Borneo), of the genera Opisthostoma W.T. & H.F. Blandford, 1860 and Plectostoma H. Adams, 1865 (Gastropoda: Architaenioglossa: Diplommatinidae)

Six new species of the genera Opisthostoma W.T. & H.F. Blandford, 1860 and Plectostoma H. Adams, 1865 (Architaenioglossa, Diplommatinidae) are described from Sarawak (Malaysia), on the island of Borneo

The land snail fauna of Batu Kudik, isolated limestone outcrop near Simunjan, Sarawak, Malaysian Borneo (Mollusca, Gastropoda)

The present study provides a checklist of land snails collected from Batu Kudik, a small and isolated limestone outcrop in Simunjan, Sarawak. A total of 24 species of land snails, representing 18 genera and 14 families were recorded, including one newly-described subspecies. The most species-rich of the families in Batu Kudik are Diplommatinidae (17%) and Chronidae (17%) with four recorded species from each of the families. Based on our analysis, Plectostoma wallacei kudikense subsp. nov., Opisthostoma javanica and Georissa pyrrhoderma were identified as the most abundant land snails at this isolated outcrop, whereas Diplommatina onyx and Everettia minuta were recorded as the least abundant. All of the land snails at Batu Kudik were exclusively found sheltered between limestone boulders, underscoring the critical role of this outcrop as their refuge for survival. Consequently, conserving this biodiversity-rich limestone area becomes paramount to prevent the local extinction of these land snail species and possibly other organisms that depend on the unique attributes of the limestone for their survival. We also provide detailed descriptions of Plectostoma wallacei kudikense, a new subspecies of the genus Plectostoma which is endemic to Batu Kudik.A description of a new subspecies Plectostoma wallacei kudikense subsp. nov

Five times over: 42 new Angustopila species highlight Southeast Asia's rich biodiversity (Gastropoda, Stylommatophora, Hypselostomatidae).

The Southeast Asian genus Angustopila, currently comprising 13 nominal species, encompasses the world's tiniest land snails. This work shows that there are far more species than previously suspected, and that this genus is in fact, a very speciose group of tiny snails widely distributed in Southeast Asia. Angustopila is revised based on type material of known species as well as 211 samples newly collected in China, Laos, Myanmar, Thailand and Vietnam. Altogether, 53 species and one subspecies are recognised, of which 42 species and subspecies are new to science: A.akrodon Páll-Gergely & Hunyadi, sp. nov., A.apiaria Páll-Gergely & Hunyadi, sp. nov., A.apiostoma Páll-Gergely & Vermeulen, sp. nov., A.apokritodon Páll-Gergely & Hunyadi, sp. nov., A.antidomedon Páll-Gergely & Hunyadi, sp. nov., A.babel Páll-Gergely & Vermeulen, sp. nov., A.bathyodon Páll-Gergely & Hunyadi, sp. nov., A.bidentata Páll-Gergely & Jochum, sp. nov., A.cavicola Páll-Gergely & Dumrongrojwattana, sp. nov., A.cicatricosa Páll-Gergely & Vermeulen, sp. nov., A.coprologosuninodus Páll-Gergely & Grego, ssp. nov., A.erawanica Páll-Gergely & Dumrongrojwattana, sp. nov., A.fratermajor Páll-Gergely & Vermeulen, sp. nov., A.fraterminor Páll-Gergely & Vermeulen, sp. nov., A.gracilis Páll-Gergely & Hunyadi, sp. nov., A.halongensis Páll-Gergely & Vermeulen, sp. nov., A.hyron Páll-Gergely & Vermeulen, sp. nov., A.maasseni Páll-Gergely & Vermeulen, sp. nov., A.majuscula Páll-Gergely & Hunyadi, sp. nov., A.margaritarion Páll-Gergely & Hunyadi, sp. nov., A.megastoma Páll-Gergely & Vermeulen, sp. nov., A.occidentalis Páll-Gergely & Hunyadi, sp. nov., A.oostoma Páll-Gergely & Vermeulen, sp. nov., A.papaver Páll-Gergely & Hunyadi, sp. nov., A.parallela Páll-Gergely & Hunyadi, sp. nov., A.prolixa Páll-Gergely & Hunyadi, sp. nov., A.pusilla Páll-Gergely & Hunyadi, sp. nov., A.pustulata Páll-Gergely & Hunyadi, sp. nov., A.quadridens Páll-Gergely & Vermeulen, sp. nov., A.rara Páll-Gergely & Hunyadi, sp. nov., A.reticulata Páll-Gergely & Hunyadi, sp. nov., A.somsaki Páll-Gergely & Hunyadi, sp. nov., A.steffeki Páll-Gergely & Grego, sp. nov., A.tetradon Páll-Gergely & Hunyadi, sp. nov., A.thersites Páll-Gergely & Vermeulen, sp. nov., A.tonkinospiroides Páll-Gergely & Vermeulen, sp. nov., A.tridentata Páll-Gergely & Hunyadi, sp. nov., A.tweediei Páll-Gergely & Hunyadi, sp. nov., A.uvula Páll-Gergely & Hunyadi, sp. nov., A.vandevenderi Páll-Gergely & Jochum, sp. nov., A.vitrina Páll-Gergely & Hunyadi, sp. nov., A.vomer Páll-Gergely & Hunyadi, sp. nov., A.werneri Páll-Gergely & Hunyadi, sp. nov. Angustopilasubelevata Páll-Gergely & Hunyadi, 2015 is moved to the synonymy of Angustopilaelevata (F. G. Thompson & Upatham, 1997), and A.singuladentis Inkhavilay & Panha, 2016 is a junior synonym of A.fabella Páll-Gergely & Hunyadi, 2015. Three species, namely A.elevata, A.fabella and A.szekeresi, are widespread over several hundred kilometres while some other species (A.huoyani, A.parallelasp. nov., A.cavicolasp. nov.) are known from just two sites a few hundred kilometres apart. All others are small range or single-site endemics. The reproductive anatomy of A.erawanicasp. nov. is described