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Department of Plant Biology, University of Illinois, 265 Morrill Hall, 505 S. Goodwin Avenue, Urbana, Illinois 61801
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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Two pyrenomycetes in the Annulatascaceae described from freshwater, Annulatascus triseptatus and Ascolacicola austriaca, are reported from North and South America for the first time. Both species occur commonly on submerged wood in the U.S.A. The two taxa are similar morphologically in having black coriaceous ascomata, cylindrical necks, septate paraphyses, cylindrical pedicellate asci with prominent apical rings and three-septate ascospores. Molecular data demonstrates that Annulatascus is polyphyletic, with A. triseptatus on a clade widely separated from the type species of the genus, A. velatisporus. Ascolacicola austriaca is on a monophyletic clade within the Annulatascaceae as sister taxon of A. triseptatus. Based on morphological data and phylogenetic analyses of 28S rDNA sequence data, new genera Annulusmagnus and Ascitendus are established for Annulatascus triseptatus and Ascolacicola austriaca, respectively.
Key words: Annulatascus, Ascolacicola, freshwater ascomycetes, molecular systematics, 28S rDNA
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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To better understand the relationship between Annulat. triseptatus and Ascol. austriaca and the relationship of these two taxa with other members of the Annulatascaceae, we conducted phylogenetic analyses of 28S rDNA sequences of three species of Annulatascus, two species of Ascolacicola, five isolates of Annulat. triseptatus, four isolates of Ascol. austriaca, and a variety of other pyrenomycetes with large apical ascus rings and septate ascospores.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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. Specimens are deposited at ILL unless otherwise indicated. Cultures used in this study were obtained from single ascospores or asci according to the procedures of Shearer (1993) and Fallah and Shearer (2001) and are deposited at the Department of Plant Biology, University of Illinois Fungus Collection. We compared our collections of Annulat. triseptatus and Ascol. austriaca with their respective type specimens to confirm the identities of our isolates.
Taxon selection. –
Species were selected for the molecular analyses based on morphological similarity and current taxonomic placement (Eriksson et al 2003). Representatives from all genera in the Annulatascaceae currently available in GenBank were included in our study, except for seven species, which were excluded based on the results of Raja et al (2003). Representatives from other families in the Sordariales (Sordariaceae and Lasiosphaeriaceae) and available species of other families of pyrenomycetous fungi with large or distinctive apical rings and septate ascospores also were included (e.g., Amphisphaeriaceae, Xylariaceae and Ascotaiwania incert. sed.).
DNA extraction, amplification and sequencing. –
DNA was extracted, amplified and sequenced following the procedures of Campbell et al (2003b) and Raja et al (2003).
Phylogenetic analyses. –
Cladistic analyses were performed in PAUP* 4.0b10 (Swofford 2002) using maximum parsimony, weighted parsimony and maximum likelihood analyses. Outgroup comparison was used to polarize the character states and hence root the trees (Darlu and Tassey 1987, Farris 1982, Stevens 1980, Watrous and Wheeler 1981). Several basal ascomycetes were explored as outgroup taxa (data not shown), and Pezizales was chosen employing the strategies of Maddison et al (1984) and Campbell (1999). Maximum parsimony analyses were performed with heuristic searches employing random starting trees, random stepwise addition on 100 replicates, gaps treated as missing and a tree-bisection-reconnection branch-swapping algorithm. Weighted parsimony analyses were performed using a step matrix to weight nucleotide transformations based on the reciprocal of the observed transition:transversion (ti/tv) ratio (Spatafora et al 1998) and heuristic searches as described above. Maximum likelihood settings were calculated using Modeltest (Posada and Crandall 1998), which selects the appropriate evolutionary model for the dataset. Analyses then were performed with heuristic searches, base frequencies set as indicated by Modeltest, the evolutionary model set to the general time reversible model of substitution (Rodriguez et al 1990) assumed with among-site rate variation described by gamma distribution as calculated in Modeltest, random starting trees with as-is addition of taxa, and a tree-bisection-reconnection branch-swapping algorithm. The alternative topologies under each evolutionary model were tested using the Kishino-Hasegawa (K-H) maximum likelihood and maximum parsimony tests (Kishino and Hasegawa 1989), with – ln L values, consistency index (CI), retention index (RI) and rescaled consistency index (RC) calculated for each tree generated. Where more than one tree was generated in an analysis, the K-H test was applied to those trees first and the best tree from that analysis used in the K-H test on the alternative models. Maximum parsimony bootstrap analyses (Felsenstein 1985) were performed on 1000 replicates using heuristic searches employing random starting trees, random stepwise addition on 10 replicates, gaps treated as missing and a tree-bisection-reconnection branch-swapping algorithm. Decay indices (Bremer 1988, 1994) were calculated in AutoDecay (Eriksson 1998). Bayesian posterior probability (Rannala and Yang 1996, Zhaxybayeva and Gogarten 2002) was calculated using Markov Chain Monte Carlo methods with MrBayes (Huelsenbeck and Ronquist 2001). The dataset was analyzed with the general time reversible model of substitution (Rodriguez et al 1990) assumed with among-site rate variation described by gamma distribution and a proportion of the sites invariable. Thirty two simultaneous Markov chains were run from random starting trees for 1 000 000 generations and sampled every 10 generations (generating 100 001 trees). The first 14 470 generations (1448 trees) of the chain were discarded as burn-in (the time for the chain to reach stability), hence inferences of posterior probability were made on 98 554 trees.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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, 2), length 2247, CI of 0.44, RI of 0.63, RC of 0.27 and – ln L of 11 599.32843, was the best phylogenetic hypothesis for the dataset, but there was no significant difference in the tree topologies.
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). One clade contains Chaetosphaeriaceae, Lasiosphaeriaceae and Sordariaceae, and the other clade contains Annulatascaceae. This indicates that Annulatascaceae does not belong in the Sordariales, a finding also observed by Huhndorf (personal communication) and is being investigated by her lab so will not be treated further in this paper.
Annulatascaceae is monophyletic (fIG. 2). The type genus, Annulatascus, is polyphyletic with the three included species (i.e., A. velatisporus, A. hongkongensis, A. triseptatus) dispersed on widely separated clades: Annulat. velatisporus, the type species, is on a clade with Annulat. hongkongensis (FIG. 1, Clade C); and Annulat. triseptatus is placed on a bifurcating clade with Ascol. austriaca (FIG. 1, Clade A).
Trichosphaeriaceae sensu Barr (1990) is polyphyletic in this study (FIG. 2). The two representative genera of the family, Trichosphaeria pilosa and Rhamphoria delicatula, are placed in widely separated clades with Trichosphaeria, the type genus, placed basally on the tree on a monophyletic clade (FIG. 1, Clade F). Rhamphoria is placed within the Annulatascaceae (FIG. 1, Clade D).
Five species in the genus Ascotaiwania, morphologically similar to Ascol. austriaca in having long cylindrical asci with large apical rings and pigmented phragmoseptate ascospores with lighter pigmented end cells, are on a monophyletic clade (FIG. 1, Clade E) widely separated from the clade of Annulatascaceae.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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, Clades A and C) with the three included species occurring on two distinct clades. This finding also was reported in Campbell et al (2003b) and Raja et al (2003). These clades represent distinct taxonomic entities at the generic level based on both molecular and morphological data.
Annulatascus triseptatus. –
Wong et al (1999) described Annulatascus triseptatus for a fungus that has black perithecia with necks, tapering hyaline paraphyses, a relatively large bipartite apical ring and ascospores that are fusiform, hyaline, three septate, slightly constricted at each septum and surrounded by a thin mucilaginous sheath. They compared its morphology to that of Annulat. velatisporus K.D. Hyde, Annulat. biatriisporus K.D. Hyde, Annulat. palmietensis K.D. Hyde, Goh et T.D. Steinke, and Annulat. bipolaris K.D. Hyde (now Cataractispora bipolaris [K.D. Hyde] K.D. Hyde, S.W. Wong et E.B.G. Jones) and included it in Annulatascus based on the shared morphological characters of dark ascomata, wide tapering paraphyses, long cylindrical asci with a relatively massive apical ring and hyaline, fusiform ascospores with a sheath.
We examined 26 collections of Annulat. triseptatus. Comparison of our collections with the description of the holotype revealed some morphological differences between our isolates and the original description (Wong et al 1999). These differences include: the presence in the holotype of a hyaline apex on the neck; ascospores constricted at the septa; and the presence of an ascospore sheath. These features were not observed in any of our collections of Annulat. triseptatus. Our collections also had a wider range in ascospore dimensions than those given for the type specimen, and the ascospores were flattened on one side (FIG. 6). In addition, we observed that the asci are deciduous (FIG. 8), they extend in water and that, for asci mounted in water, there is a back-door ascospore discharge through dissolution of the basal part of the ascus (FIG. 9). None of these observations were reported for the holotype. The type specimen of Annulat. triseptatus no longer is available, and a neotype has not been designated (K.D. Hyde pers comm). However, another collection of Annulat. triseptatus was sent to us from HKU as an authentic specimen of Annulat. triseptatus (K.D. Hyde pers comm). This specimen was similar to our collections in that the neck was black with a pale yellow-brown apex and the ascospores were not constricted at the septa, were flattened on one side and lacked a gelatinous sheath. Hence, we are confident that our collections are correctly identified as Annulat. triseptatus. In the absence of a type specimen for Annulat. triseptatus, herein we select Hyde’s specimen HKU 889 as the neotype specimen.
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, 26–30) as opposed to a wedge-shaped apical ring (fIGS. 33, 34); ascospores that are hyaline, but which may become pale straw-colored or brown with age, 3 septate, smooth-walled when viewed with the light microscope, but warted when viewed with SEM, broadly fusiform, flattened on one side, guttulate and with or without a gelatinous sheath (fIGS. 6, 7, 35), compared to hyaline, unicellular, verruculose at the light microscope level, fusiform ascospores surrounded by a mucilaginous sheath (FIG. 36). Of note, the ascus apical ring of species of Annulatascaceae becomes transparent in lactic acid (FIG. 29) but remains visible when fixed in glycerin (fIGS. 26, 28, 33).
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Based on the aforementioned phenotypic differences and analyses of molecular data that indicate that Annulat. triseptatus is phylogenetically distinct from the type species of Annulatascus, a new genus, Annulusmagnus, is proposed to accommodate Annulatascus triseptatus.
Annulusmagnus J. Campb. et Shearer, gen. nov.
Ascomata globosa vel suboblata, nigra. Rostrum cylindricum, periphysatum. Asci excrescentes in aquâ, cylindracei, unitunicati, pedicellati, apparatum apicalem magnum praediti, labis caerulei poirreri aquosi ope caerulescentum. Hamathecium cum latis, tum coarctantibus paraphysibus. Ascosporae hyalinae, fusiformae, cum complanato uno lateretria, septata.
Type species.. Annulusmagnus triseptatus (S.W. Wong, K.D. Hyde et E.B.G. Jones) J. Campb. et Shearer. comb. nov.
Etymology.. From the Latin annulata = ring, and magnus = large, in relation to the large refractive ascus apical ring.
Annulusmagnus triseptatus (S.W. Wong, K.D. Hyde et E.B.G. Jones) J. Campb. et Shearer, comb.nov. FIGS. 3–9
Basionym: Annulatascus triseptatus S.W. Wong, K.D. Hyde et E.B.G. Jones. Mycol. Res. 103:563. 1999.
Colonies on peptone-yeast-glucose (PYG) agar immersed, brown, spreading, comprised of brown, septate, branched hyphae. Ascomata on wood separate to clustered, immersed to semi-immersed, erumpent or superficial with base slightly immersed, black, coriaceous, roughened on the outside with short setose-like hyphae, oblate to suboblate to globose, ostiolate with a prominent neck, venter 375–660 x 400–700 µm (FIG. 3). Ascomal wall in longitudinal section 42–50 µm thick, comprised of three layers (FIG. 3): outer layer of thick-walled cells occluded with dark brown amorphous material; middle layer of brown, thin-walled, isodiametric to laterally compressed, elongated cells; inner layer of hyaline, laterally compressed, elongated, hyaline cells; in surface view, black, opaque, in upper part of textura angularis covered with short protruding hyphae and in lower part of textura prismatica. Neck central, cylindrical to conical, 88–340 x 80–150 µm, black to dark brown, yellow at apex, wall 2-layered, outer layer of dark brown, laterally compressed thick-walled cells occluded with brown amorphous material, thicker at base of neck, inner layer of laterally compressed hyaline cells. In moist chambers, the asci and ascospores accumulate at the apex of the neck. Hamathecium paraphysate; paraphyses numerous, not immersed in gelatinous material, longer than asci, 165–210 µm long, 4–10 µm wide at base, tapering to 2–3 µm at apex, 2–7 septate. Asci functionally unitunicate, cylindrical, pedicellate, (114–)138–283 x 7–14 µm (FIG. 8), separating from the hymenial layer at maturity (deciduous), expanding an additional 10–30 µm in length on contact with water, discharging ascospores by dissolution of basal one-third to one-half of ascus (back-door discharge) (FIG. 9), with prominent, bipartite, doughnut-shaped apical ring, 2–4 x 3–5 µm, tapering 1–2 µm from top to bottom (fIGS. 4, 5), with a subapical flange (FIG. 4) that is not visible in glycerin (FIG. 29), channel through pore 1–2 µm wide (FIG. 5); ascus ring MLZ negative, lower part staining, upper part not staining in aqueous cotton blue and nigrosin. Ascospores (fIGS. 6, 7) hyaline, multiguttulate, becoming pale straw-colored or pale brown with age, overlapping uniseriate (FIG. 8), becoming uniseriate in water, fusoid, flattened or occasionally slightly concave on one side, 3 septate, 16–37 x 5–10 µm, smooth-walled in transmitted light, rough-walled in SEM, with or without a thin, adpressed gelatinous sheath.
Anamorph.. Unknown
Etymology.. From the Latin triseptatus, in reference to the ascospores that are three septate.
Specimens examined.. AUSTRALIA: Koah, Clohiesy River, on submerged wood, 31 Dec 1991, K.D. Hyde, HKU 889 (Neotype). Additional specimens examined were collected from Canada (Ontario and Manitoba), the USA (AR, IL, ME, MI, MN, NC, NH, NY, OR, TN, VA, WI) and Venezuela. Detailed collection information is available from the authors and has been deposited with the herbarium specimens. This fungus occurred on submerged corticated or decorticated wood in both lotic and lentic habitats and causes soft-rot cavities on balsa wood in culture. Specimens were collected from latitudes 7–65°N and 17°S, and longitudes 4–124°W and 145°E, at temperatures ranges of 8–32 C and pH of 4–6 (8). There is a large range of ascospore measurements among collections, but we could not detect geographically distinctive patterns in size.
Ascolacicola austriaca. –
Réblová and Winka (2001) described Ascol. austriaca for a fungus that has dark brown perithecia with necks, tapering paraphyses, a wedge-shaped ascus apical ring and ascospores that are ellipsoidal to fusiform, slightly curved and tapering at the ends, 3 septate, brown, with the two central cells darker brown than the two end cells. They found that molecular data indicated that this taxon belongs in the Annulatascaceae, and they placed it in the genus Ascolacicola based on morphological similarities. Ranghoo et al (1999), who established the genus, had placed Ascolacicola in the Sordariaceae based on morphology (Ranghoo and Hyde 1998).
We examined 27 collections of Ascol. austriaca, including the holotype. The morphology of Ascol. austriaca differs from that of the type species of the genus, Ascol. aquatica, with respect to peridium, paraphyses, ascus apical ring and ascospores. The peridium of Ascol. austriaca consists of 2–3 layers, an outer layer of brown cells becoming elongated toward the center and an inner layer of hyaline, elongated, compressed cells, compared to that of Ascol. aquatica, which comprises a single layer, 5–7 cells wide: cells angular, brown, flattened. The paraphyses of Ascol. austriaca are 4–10 µm wide at the base and taper to 2–3 µm at the apex (FIG. 14), compared to the paraphyses of Ascol. aquatica, which are rounded at the apex and 2.5–3.8 µm wide. The ascus apical ring of Ascol. austriaca (FIG. 13) is wedge-shaped (2.5–4.5 high and 3–3.8 µm wide), compared to the ascus apical ring of Ascol. aquatica, which is discoid (2.5–3.7 µm high and 6.2 µm wide). The ascospores of Ascol. austriaca are brown with slightly paler end cells, ellipsoidal to fusiform, straight or slightly curved and tapering at the ends (fIGS. 18–20), with the wall roughened in a striated pattern visible with the light microscope (fIGS. 24, 25), compared to the ascospores of Ascol. aquatica, which are ellipsoidal, hyaline, 3 septate, rounded at the apex and smooth-walled. In addition, an anamorphic state has not been observed for Ascol. austriaca, but Trichocladium uniseptatum is the known anamorph of Ascol. aquatica (Ranghoo and Hyde 1998). Ascolacicola austriaca has morphological characteristics of both Annulatascus K.D. Hyde, Annulatascaceae, Sordariales (Eriksson 2003), and Ascotaiwania Sivan. & H.S. Chang, incert. sed. (Ranghoo et al 1999). Characteristics of the ascoma and hamathecium are similar to those of Annulatascus. It also has a prominent ascus apical apparatus (fIGS. 31, 32) and asci (fIGS. 15, 16) similar to those found in Annulatascus and Ascotaiwania. The versicolored, phragmoseptate ascospores, however, (fIGS. 18–20, 37) are more similar to the ascospores of Ascotaiwania, which are fusoid, phragmoseptate and brown with lighter pigmented end cells, than to the ascospores of Annulatascus, which are fusiform, 0–3 septate, hyaline and have a thin sheath or appendages (FIG. 36).
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, 37), compared to hyaline (may become pale straw-colored or brown throughout with age) in Annulus. triseptatus (fIGS. 6, 7, 35). In addition, the ascospores of Ascol. austriaca are curved and narrowly fusiform (fIGS. 18–20, 37) while those of Annulus. triseptatus are straight, usually flattened on one side and broadly fusiform (fIGS. 6, 7, 35). The ascospore septa of Ascol. austriaca are dark pigmented and refractile (FIG. 37) while those of Annulus. triseptatus are not (FIG. 35). The ascospore walls of Ascol. austriaca are roughened in a striated pattern visible with the light microscope (fIGS. 24, 25), while the wall roughenings on the ascospores of Annulus. triseptatus can be seen only with SEM and are randomly distributed.
Réblová and Winka (2001) performed phylogenetic analyses on the 28S rDNA sequence of Ascol. austriaca and three species of Annulatascaceae obtained from Ranghoo et al (1999), including Ascol. aquatica. They found that Ascol. austriaca was placed on a clade with Annulat. hongkongensis W.H. Ho, Ranghoo, K.D. Hyde et I.J. Hodgkiss but Ascol. aquatica was placed with Capronia semiimmersa Cand. et Sulmont. They removed Ascol. aquatica from their analyses because of its position with the loculoascomycetes, which conflicted with the description of the species. We obtained sequences from three of our 27 collections of Ascol. austriaca and performed molecular analyses along with the published sequences of Ascol. austriaca from Réblová and Winka (2001) and Ascol. aquatica from Ranghoo et al (1999). In this study (data not shown) and previous analyses (Raja et al 2003), we found that Ascol. aquatica was placed basal to the Pezizales, which is inconsistent with the original description and it therefore was removed from our analyses. In our analyses, Ascol. austriaca was placed on a bifurcating clade with Annulus. triseptatus (FIG. 1, Clade B). Species of Ascotaiwania were placed on a monophyletic clade, widely separated from Ascol. austriaca and Annulatascaceae (FIG. 1, Clade E).
Based on the aforementioned morphological differences between Ascol. austriaca and the type species of Ascolacicola, Ascol. aquatica, we conclude that Ascol. austriaca does not belong in Ascolacicola or any other genus currently included in the Annulatascaceae and a new genus, Ascitendus, is proposed for Ascol. austriaca.
Ascitendus J. Campb. & Shearer, gen. nov.
Ascomata globosa, nigra. Rostrum cylindricum, periphysatum. Asci excrescentes ad in aquâ, cylindracei, unitunicati, cum apparato apicale magnopere praediti, labis caerulei poirreri aquosi ope caerulescentum. Paraphyses latae, angustatae, septatae. Ascosporae fusiformes, curvus, ex hyalinis ad brunneas, phragmoseptatae.
Type species.. Ascitendus austriacus (Réblová, Winka et Jaklitsch) J. Campb. et Shearer.
Etymology.. From the Latin asci and tendere to stretch, in relation to the lengthening of the asci on = contact with water.
Ascitendus austriacus (Réblová, Winka et Jaklitsch) J.Campb. et Shearer, comb. nov. FIGS. 10–25
Basionym: Ascolacicola austriaca Réblová, Winka et Jaklitsch. Mycologia, 93:487. 2001.
Colonies on PYG agar immersed, brown, spreading, comprised of brown, septate, branched hyphae. Ascomata on wood separate to clustered, densely aggregated in patches, immersed to superficial, black, coriaceous, globose to subglobose, ostiolate with a prominent neck, venter 350–585 x 295–505 µm (FIG. 10). Ascomal wall in longitudinal section 28–42 µm thick, comprised of three layers: outer layer of pseudoparenchyma cells occluded with brown amorphous material; middle layer of brown, thin-walled, laterally compressed, elongated cells; inner layer of hyaline, laterally compressed, elongated, hyaline cells; in surface view, black, opaque (FIG. 11). Neck central, cylindrical, periphysate, 85–300(–460) x 50–140 µm, black at base, pale yellow at apex (FIG. 12), wall 2-layered, outer layer of dark brown, laterally compressed thin-walled cells occluded with brown amorphous material, inner layer of laterally compressed thin-walled hyaline cells. Hamathecium paraphysate; paraphyses longer than asci, 120–190 µm long, 4–10 µm broad at base, tapering to 2–3 µm, 1–9 septate (FIG. 14). Asci functionally unitunicate, cylindrical, 100–160 x 4–6 µm, expanding up to 260 x 8 µm in water, separating from the hymenial layer, pedicellate (fIGS. 15, 16, 23), with a prominent cylindrical to flaring apical apparatus (fIGS. 13, 21, 31, 32), 2.5–3.5 µm long, 3.0–3.8 µm wide at apex, 2–3 µm wide at base; ascus apparatus MLZ negative, staining positive in aqueous cotton blue (for mature asci only) and nigrosin, discharging ascospores through the ascus apical ring or by dissolution of lower one-third to one-half of ascus when in water (FIG. 17). Ascospores pale brown, fusoid, curved, 3-septate in sequence 2: 1:2 or 3:1:2, 14–27 x 4–9 µm, middle cells darker than outer cells, each cell with a single large guttule, not constricted at septa; septa prominent, pigmented brown, with small refractive dots at ends (fIGS. 18–20, 22); wall roughened in a striated pattern (fIGS. 24, 25); without appendages or a sheath.
Anamorph. – Unknown.
Etymology. –
The epithet austriacus refers to the country from which this species was originally collected (Réblová and Winka 2001).
Specimens examined. – AUSTRIA: Wien 19, Hermannskogel, on submerged wood of Fagus sylvatica, 29 Aug 1998, W. Jaklitsch, WJ 1131-98 (HOLOTY PE, PRM 842991). Culture ex type: CBS 102665. Additional specimens examined were collected from Canada (Ontario and Manitoba), the USA (AR, IL, ME, MN, MS, NC, NH, NY, OR, TN, VA, WI) and Venezuela. Detailed collection information is available from the authors and has been deposited with the herbarium specimens. This fungus occurred on submerged corticated and decorticated wood in both lotic and lentic habitats and causes soft-rot cavities on balsa wood in culture. Specimens were collected from latitudes 7–51°N and longitudes 69–95°W and 48°E, at temperatures of 4–30 C and pH of 4–6.5 (7.5).
Rhamphoria delicatula. –
Trichosphaeriaceae sensu Barr (1990) is polyphyletic in this study with the two representative genera of the family, Trichosphaeria pilosa (Pers. : Fr.) Fuck. and Rhamphoria delicatula Niessl, placed in widely separated clades. Rhamphoria is placed within the Annulatascaceae, a finding that also was presented by Réblová and Winka (2001). They suggested that the placement of Rhamphoria made the Annulatascaceae polyphyletic. However, they had only three representatives of Annulatascaceae and Rhamphoria was the only representative of Trichosphaeriaceae. In our analyses, we have nine species of Annulatascaceae represented by 21 isolates and two species of Trichosphaeriaceae including the type genus, Trichosphaeria. Our findings indicate that Annulatascaceae is monophyletic and suggest that R. delicatula may belong in the Annulatascaceae. Rhamphoria is similar morphologically to genera in the Annulatascaceae in that the ascomata are black, globose, superficial, solitary to gregarious, with a short periphysate neck; the asci are cylindrical and stalked, with a nonamyloid apical ring; the ascospores are ellipsoidal, uniseriate and hyaline to lightly pigmented. It differs in having muriform spores. Samuels (Barr 1990) suggested that Rhamphoria should be referred to "a position close to Chaetosphaeria in the Sordariales." This position is not confirmed with these analyses. Rhamphoria delicatula requires further molecular and morphological study to help resolve its phylogenetic relationships and taxonomy.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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1 Corresponding author. E-mail: jcampbe2{at}life.uiuc.edu
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