The Genus Dentipratulum (Russulales, Auriscalpiaceae): Comparative Morphology and SEM Imaging Spore Ornamentation Split One Into Three Species
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Mycol Progress (2017) 16:109–116 DOI 10.1007/s11557-016-1263-z ORIGINAL ARTICLE The genus Dentipratulum (Russulales, Auriscalpiaceae): comparative morphology and SEM imaging spore ornamentation split one into three species Dariusz Karasiński1 & Marcin Piątek1 Received: 27 September 2016 /Revised: 14 December 2016 /Accepted: 16 December 2016 /Published online: 28 December 2016 # The Author(s) 2016. This article is published with open access at Springerlink.com Abstract The family Auriscalpiaceae (Russulales) includes Introduction species forming pileate, stipitate-pileate, effused-reflexed, and resupinate basidiomata. The resupinate basidiomata are An unusual mucronelloid fungus was found on fallen trunks characteristic only for the genus Dentipratulum,describedto of Picea abies (L.) H. Karst. in the BiałowieżaPrimeval accommodate Dentipratulum bialoviesense, found in the Forest, in the year 1962, by the Polish mycologist Stanisław Białowieża Primeval Forest in Poland and later reported from Domański. This fungus was similar to the genus Mucronella several locations in Eurasia. The materials assigned to this Fr. but differed in having a gloeopleurous hyphal system with genus were revised and three distinct morphospecies were gloeopleurous hyphae and gloeocystidia (lacking in detected, including Dentipratulum bialoviesense s. str. and Mucronella), and by having ornamented basidiospores two new species, Dentipratulum khuranae from India and (smooth in Mucronella). Consequently, Domański (1965)de- Dentipratulum crystallinum from the Kuril Islands and scribed a new genus Dentipratulum Domański and a new France. The concept of the genus Dentipratulum is emended species Dentipratulum bialoviesense Domański to accommo- to include characters omitted in the original diagnosis (stem- date this mucronelloid fungus. Originally, Domański (1965) like base of spines, rudimentary subiculum) and found in the placed Dentipratulum in the family Hericiaceae, but the pres- novel species (presence of naked or encrusted leptocystidia). ence of sulfocystidia detected by Boidin and Gilles (1990) All Dentipratulum species are illustrated with pictures of indicated its affinity to the family Auriscalpiaceae. This family basidiomata, line drawings of micro-morphological charac- placement was subsequently confirmed in molecular phyloge- ters, and scanning electron microscopy (SEM) micrographs netic studies (Boidin et al. 1998; Larsson and Larsson 2003; of basidiospores. A key to the genus is provided. Larsson 2007; Zhou and Dai 2013). The family Auriscalpiaceae (Agaricomycetes, Russulales) includes only four genera: Auriscalpium Gray, Dentipratulum, Gloiodon P. Keywords Eurasia . Morphospecies . Taxonomy . Karst., and Lentinellus P. Karst. (Hibbett et al. 2014), charac- Wood-inhabiting fungi terized by different morphologies of basidiomata: pileate (Lentinellus), stipitate-pileate (Auriscalpium), effused- reflexed (Gloiodon), and resupinate (Dentipratulum). Except Lentinellus species that have lamellate hymenophores, other members of the family produce hydnoid hymenophores. Macro-morphological similarities of the basidiomata of Section Editor: Zhu-Liang Yang Dentipratulum and Mucronella are not reflected in their phy- logenetic relationships. Both genera are distantly related, and * Dariusz Karasiński the type species of the genus Mucronella [M. calva (Alb. & [email protected] Schwein.) Fr.] belongs to the order Agaricales (Larsson et al. 2004). 1 Department of Mycology, W. Szafer Institute of Botany, Polish After the holotype collection, further specimens of Academy of Sciences, Lubicz 46, 31-512 Kraków, Poland Dentipratulum bialoviesense were only rarely collected. In 110 Mycol Progress (2017) 16:109–116 the Białowieża Primeval Forest, it was again found in 1973 by Herbariorum (http://sweetgum.nybg.org/ih/). The Zdenek Pouzar, labeled as Mucronella sp., and deposited in abbreviation KRAM F-SD refers to the collection of PRM and KRAM (M. Piątek, unpubl.). The extensive sam- Stanisław Domański preserved in KRAM. All specimens pling of wood-inhabiting fungi in the Białowieża Primeval were examined by LM and some specimens also by SEM. Forest in the years 2009–2016, including a large number of For LM, free-hand sections of basidiomata (spines) were mucronelloid specimens, did not yield any additional collec- made under a Nikon SMZ-2T microscope using a razor blade tion of D. bialoviesense (D. Karasiński, unpubl.). Around the or single spines were taken and analyzed under a Nikon world, Dentipratulum bialoviesense was found only a few Eclipse E400 light microscope with magnification up to times. Corner (1970) reported this fungus from the Kuril 1250×. Melzer’s reagent, 0.1% cotton blue in 60% lactic acid, Islands (specimen TAAM 12993, collected by Erast and 3% KOH solution were used as mounting media. Parmasto on Kunashir Island in the year 1960). Later, Sulfovanillin was used to observe reactions of gloeocystidia Boidin and Gilles (1990) and Boidin et al. (1998) added a and gloeopleurous hyphae. In the species descriptions, spore few specimens of D. bialoviesense from France and size range and Q value range are based on 30 measurements Switzerland: specimen Gilles 514, collected in 1985 near per collection, made in Melzer’s reagent. The 5% extreme Pontonx and Buglose (Landes, France); specimen LY values of spores are given in parentheses. Twenty measure- 12010, collected by Gérard Gilles in 1986 in Oloron-St Pée ments were performed for the remaining anatomical elements (Pyrénées-Atlantiques, France); and specimen LY 15613, col- (basidia, cystidia, and hyphae). Descriptions of macroscopic lected by M. Meyer in August 1993 in the Canton of Vaud features of all species were made based on dried specimens (Switzerland). The ITS sequence of the latter specimen was and, in the case of Dentipratulum bialoviesense s. str., it was used in one of the first phylogenetic studies referred to supplemented by characters of fresh basidiomata described in aphyllophoroid fungi (Boidin et al. 1998). One additional the original diagnosis (Domański 1965). For SEM, single specimen was found in 1984 in Landes, Carcen-Ponson, spines from selected specimens (GB-0069354, KRAM F-SD southwestern France (collection Gilles 1645). A duplicate of 4001, KRAM F-SD 5881, TAAM 12993) were glued to car- this material deposited in GB was used as the reference mate- bon tabs and fixed to aluminum stubs with double-sided trans- rial in molecular phylogenetic studies by Larsson and Larsson parent tape. The stubs were sputter-coated with carbon using a (2003) and Larsson (2007). Cressington sputter coater and viewed with a Hitachi S-4700 The herbarium of Stanisław Domański (now preserved in scanning electron microscope, with a working distance of ca. KRAM) contains, except for the holotype material of 10 mm. SEM micrographs were taken in the Laboratory of Dentipratulum bialoviesense,anadditionalspecimenlabeled FieldEmissionScanningElectronMicroscopyand as Dentipratulum sp. originating from India. This specimen Microanalysis at the Institute of Geological Sciences of the was sent to Domański by the Indian mycologist Inder Pal Jagiellonian University, Kraków, Poland. MycoBank (Crous Singh Khurana for his opinion. Judging from the correspon- et al. 2004), Index Fungorum (http://www.indexfungorum. dence attached to the specimen, this fungus was considered by org/names/names.asp), and Cortbase (Parmasto et al. 2004) Domański as a new species or at least a variety of were consulted for nomenclature and abbreviations of authors Dentipratulum bialoviesense. He additionally considered that of fungal names. the Indian specimen may be identical to material reported from the Kuril Islands by Corner (1970). This fungus was never described in the literature. Trying to resolve the enigma Results of these materials, the revision of all available Dentipratulum specimens appeared to be necessary. This study aims at resolv- Taxonomy ing the taxonomic placement of Dentipratulum specimens by careful morphological analyses using light microscopy (LM) Dentipratulum Domański, Acta Mycol. 1: 6, 1965, emend. and scanning electron microscopy (SEM), the latter made for Karasiński & Piątek the first time for the genus Dentipratulum. The comparative Basidiomata forming clusters of downwards-growing indi- morphology led to the delineation of three morphospecies, vidual spines, scattered or crowded, pointed and unbranched, Dentipratulum bialoviesense s. str. and two new species. often with more or less distinct, short, stem-like base and The concept of Dentipratulum is emended. always with a sterile apex; spines connected with very thin, rudimentary, discontinuous or continuous subiculum. Hyphal system monomitic, generative hyphae with clamp connec- Materials and methods tions, hyaline or rarely brownish in subiculum and at the base of spines, thin to slightly thick-walled. Gloeopleurous hyphae This study is based on specimens deposited in GB, KRAM, and gloeocystidia present, sulfopositive, usually with strong LY, and TAAM. Herbarium acronyms are according to Index reaction. Leptocystidia present in some species, fusoid to Mycol Progress (2017) 16:109–116 111 cylindrical, sometimes encrusted. Basidia clavate, constricted to subutriform, sometimes stalked, with four or rarely two sterigmata, with basal clamp. Basidiospores broadly ellipsoi- dal to globose, 3.5–6 μm in diameter, slightly thick-walled, apiculate, ornamented, strongly amyloid, acyanophilous. Type species: Dentipratulum bialoviesense Domański. Dentipratulum