ABSTRACT
The genus Alpioniscus Racovitza, 1908 (Trichoniscidae) from Sardinia is revised. Three new cave-dwelling species are described: A.onnisi Taiti & Argano, sp. n., A.stochi Taiti & Argano, sp. n., and A.sideralis Taiti & Argano, sp. n.. The genus Utopioniscus Schmalfuss, 2005 is considered to be a junior synonym of Alpioniscus, after morphological and molecular analyses. Alpioniscusfragilis (Budde-Lund, 1909) and A.kuehni from Grotta del Bue Marino are illustrated. With the new species, the genus Alpioniscus in Sardinia comprises six species: two troglobionts (A.fragilis and A.onnisi), one endogean and troglobiont (A.thanit Taiti & Argano, 2009), and three stygobionts (A.kuehni, A.stochi, and A.sideralis). All the species occur in karstic areas in the central-eastern and south-eastern part of the island. A key to all the Sardinian species of Alpioniscus is provided.
ABSTRACT
The bacterial diversity in the Su Bentu Cave in Sardinia was investigated by means of 16S rRNA gene-based analysis. This 15 km long cave, carved in Jurassic limestone, hosts a variety of calcite speleothems, and a long succession of subterranean lakes with mixed granite and carbonate sands. The lower level is occasionally flooded by a rising groundwater level, but with only scarce input of organic remains (leaves and charcoal fragments). On the quiet cave pools there are visible calcite rafts, whereas walls are locally coated with manganese deposits. In the drier upper levels, where organic input is much more subdued, moonmilk-a hydrated calcium-magnesium carbonate speleothem-can be found. Relative humidity approaches 100% and the measured mean annual cave air temperature is 14.8°C. Samples were obtained in 2014 from calcite rafts, moonmilk, manganese oxide deposits and soil (limestone and granite grains). Microclimatic conditions in the cave near the sampling sites, sample properties, physico-chemical parameters of water, and sediment composition were determined. The microbial community of this system is predominately composed of the phyla Proteobacteria, Actinobacteria, Acidobacteria, Nitrospirae, and Firmicutes. Sampling sites near the entrance of the cave and in close proximity of the underground campsite-located 500 meters deep into the cave-revealed the highest diversity as well as the highest number of human associated microorganisms. Two samples obtained in very close proximity of each other near the campsite, indicate that the human impact is localized and is not distributed freely within the system. Analysis of the abundance of bacterial and archaeal amoA genes revealed a far greater abundance of archaeal amoA genes compared to bacterial representatives. The results of this study highlight that human impact is confined to locations that are utilized as campsites and that exploration leaves little microbial trails. Furthermore, we uncovered a highly specialized microbiome, which is perfectly adapted to survive and thrive in an environment with low nutrient availability.
Subject(s)
Camping , Caves/microbiology , Microbiota , Ammonia/chemistry , Archaea/isolation & purification , Bacteria/isolation & purification , Calcium Carbonate/chemistry , Italy , Oxidation-Reduction , Soil MicrobiologyABSTRACT
Typhloreicheia monachasp. n. and Typhloreicheia ilianaesp. n. are described from two caves of Central-Eastern Sardinia (Nuoro province): the Bue Marino cave and the Nurra 'e Pradu cave, respectively. Both caves are located in the part of the island where many highly specialised subterranean carabid beetles are localised. Typhloreicheia monacha is apparently related to two other species of the same area, i.e. Typhloreicheia onnisi Casale & Magrini, 2004 and Typhloreicheia elegans (Dodero, 1916); Typhloreicheia ilianae is closely related to Typhloreicheia henroti Jeannel, 1957, known from a cave near Dorgali. Relationships and diagnostic features among these taxa are discussed and illustrated, and a key for identification of the specialised subterranean Typhloreicheia species of Sardinia is provided. The hypothesis of adaptive radiation of Reicheiina species in Sardinia, recently proposed by the senior author of this contribution, is further elaborated in light of new data.
