377 Alberto M. STCHIGEL 1 , Josep CANO 1 , Walter MAC CORMACK 2 and Josep GUARRO 1  Unitat de Microbiologia, Facultat de Medicina i Cie  ncies de la Salut & Institut d’Estudis Avançats, Universitat Rovira i Virgili, CSant Llorenç. 21, 43201 Reus, Spain  Instituto Anta  rtico Argentino, Departamento de Biologı  a, CCerrito 1248 (1010), Buenos Aires, Argentina. E-mail : umbfmcs.urv.es Received 12 November 1999 ; accepted 4 July 2000. A new ascomycete, Antarctomyces psychrotrophicus gen. et sp. nov., characterised by naked asci, hyaline, thick-walled, ellipsoidal to fusiform, echinulate ascospores, and blastoconidia, isolated from Antarctican soil samples, is described and illustrated. Analysis of the nuclear rDNA ITS region sequences showed that this taxon is related to Thelebolaceae. INTRODUCTION During the summer expedition of the ‘ Instituto Anta  rtico Argentino ’ to the Antarctica, W. M. C. collected soil samples near the ‘ Jubany ’ Argentinian base (King George Island, South Shetland Islands). Two strains of an undescribed ascomycete were isolated in axenic culture. These were characterised by rudimentary ascomata, composed of a cluster of a small number of asci without a peridium, and hyaline, ellipsoidal to fusiform, spinulose ascospores. It was difficult to determine its taxonomic placement from morphological characteristics alone, so we compared the sequence of its ITS region with those of other morphologically similar fungi of uncertain taxonomic position, and also representatives of Eurotiales, Onygenales, Pezizales and Sordariales. MATERIALS AND METHODS Fungal isolation Soil samples were collected near the ‘ Jubany ’ Argentinian base (62 14 S, 58 40 W) on King George Island, South Shetland Islands, Antarctica. The terrain is basically basaltic and metamorphosed rocks, and penguin dung is very common. The vegetation is mainly algae as Prasiola crispa, lichens (including Acarospora molybdina, Lecidea auriculata, Caloplaca spp.), mosses (Andreaea depressinervis, A. regularis, Brachytecium antarcticum, Bryum dichotomum, Grimnia antartici, Hypnum sarmentosum, Pogonatum alpinum, Tortula excelsa, etc.), and the plants Colobanthus quitensis, Deschampsia antarctica and Poa pratensis (Cabrera 1994, Lindsay 1971, Mo  ller & Dreyfuss 1996). The following climatic data were reported for 1995 : average temperature 15 C, minimum of 199  and maximum of 104  ; total annual precipitation 273 mm, and total annual snowfall 1257 cm ; and the average humidity was 88 %. Material was collected mainly from the A horizon, placed into sterilised polyethylene bags closed by rubber band, and stored in a refrigerator at 20 . Fungal isolation was by the soil plate method (Warcup 1950) in which suspensions were cultured on potato carrot agar with 30 mg l - chloramphenicol (PCA ; potatoes, 20 g ; carrot, 20 g; agar, 20 g; tap water, 1 l). We also used a modification of Furuya and Naito’s method (1979). About 1 g of soil was suspended in 5 ml of 5 % vv acetic acid, shaken vigorously for 5 min, and left for a further 5 min. The layer of acetic acid was decanted, the residual soil resuspended with 9 ml of sterilised water, and the suspensions plated in a Petri dish. PCA with chloramphenicol was placed on top of the soil suspension and mixed. All cultures were incubated at 11–12 under 12 h of darkness, alternating with 12 h of cool white fluorescent light. The strains were grown on oatmeal agar (OA ; Difco), PCA, potato dextrose agar (PDA ; Difco) and malt extract agar (MEA ; Difco) at room temperature (22–25 ), 11–12 , and 4–6  under 12 h of darkness, alternating with 12 h of cool white fluorescent light. Colour notations in parentheses are from Kornerup & Wanscher (1984). Structures were measured in lactophenol. Molecular study Table 1 lists the strains used in the study. The sequences obtained from Momol & Kimbrough (1994) are not available in any DNA sequences database checked. Monascus purpureus, Neurospora crassa and Talaromyces flavus var. macrosporus were obtained from EMBL. New sequences were obtained for Amauroascus niger, Amauroascus volatilis-patellus, Antarctomyces psychrotrophicus, Aphanoascus keratinophylus, Calyptrozyma Mycol. Res. 105 (3) : 377–382 (March 2001). Printed in the United Kingdom. Antarctomyces psychrotrophicus gen. et sp. nov., a new ascomycete from Antarctica