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2-2018 New Classification of the Dictyostelids Sanea Sheikh

Mats Thulin

James C. Cavender

Ricardo Escalante

Shin-ichi Kawakami

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Recommended Citation Sheikh, Sanea; Thulin, Mats; Cavender, James C.; Escalante, Ricardo; Kawakami, Shin-ichi; Lado, Carlos; Landolt, John C.; Nanjundiah, Vidyanand; Queller, David C.; Strassmann, Joan E.; Spiegel, Frederick W.; Stephenson, Steven L.; Vadell, Eduardo M.; and Baldauf, Sandra L., "New Classification of the Dictyostelids" (2018). Biology Faculty Publications & Presentations. 151. https://openscholarship.wustl.edu/bio_facpubs/151

This Article is brought to you for free and open access by the Biology at Washington University Open Scholarship. It has been accepted for inclusion in Biology Faculty Publications & Presentations by an authorized administrator of Washington University Open Scholarship. For more information, please contact [email protected]. Authors Sanea Sheikh, Mats Thulin, James C. Cavender, Ricardo Escalante, Shin-ichi Kawakami, Carlos Lado, John C. Landolt, Vidyanand Nanjundiah, David C. Queller, Joan E. Strassmann, Frederick W. Spiegel, Steven L. Stephenson, Eduardo M. Vadell, and Sandra L. Baldauf

This article is available at Washington University Open Scholarship: https://openscholarship.wustl.edu/bio_facpubs/151 Manuscript Click here to view linked References

1 2 ORIGINAL PAPER 3 4 A New Classification of the Dictyostelids 5 6 Sanea Sheikha, Mats Thulina, James C. Cavenderb, Ricardo Escalantec, Shin-ichi Kawakamid, 7 Carlos Ladoe, John C. Landoltf, Vidyanand Nanjundiahg, David C. Quellerh, Joan E. 8 Strassmannh, Frederick W. Spiegeli, Steven L. Stephensoni, Eduardo M. Vadellj, and Sandra 9 a,1 10 L. Baldauf 11 12 13 a Programme in Systematic Biology, Uppsala University, Norbyvägen 18D, Uppsala SE- 14 15 75236, Sweden 16 b 17 Departmental of Environmental and Plant Biology, Ohio University, Athens, Ohio 45701, 18 USA 19 c 20 IIB, Instituto de Investigaciones Biomédicas “Alberto Sols”, CSIC-UAM. Arturo Duperier 4, 21 28029-Madrid, Spain

22 d 23 Yamagata Prefectural Museum, 1-8 Kajo-machi, Yamagata-shi, Yamagata-ken 990-0826, 24 Japan

25 e 26 Real Jardín Botánico de Madrid, CSIC, Plaza de Murillo 2, 28014 Madrid, Spain 27 f 28 Department of Biology, Shepherd University, Shepherdstown, West Virginia 25443, USA 29 g 30 Centre for Human Genetics, BioTech Park, Electronic City (Phase I), Bangalore 560100, 31 India

32 h 33 Department of Biology, Washington University in Saint Louis, Campus Box 1137, One 34 Brookings Drive, Saint Louis, MO, USA 35 i 36 Department of Biological Sciences, SCEN 601, 850 W. Dickson 1, University of Arkansas, 37 Fayetteville, AR 72701 USA 38 39 jEscuela de Farmacia y Bioquímica, J.F. Kennedy University, Buenos Aires, Argentina 40 41 42 43 Submitted March 3, 2017; Accepted October 17, 2017 44 45 Monitoring Editor: Alastair Simpson 46 47 48 49 Running title: New Classification of Dictyostelids 50 51 52 1 53 Corresponding author; e-mail [email protected] (S. L. Baldauf). 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Traditional morphology-based taxonomy of dictyostelids is rejected by molecular 3 4 phylogeny. A new classification is presented based on monophyletic entities with 5 consistent and strong molecular phylogenetic support and that are, as far as possible, 6 7 morphologically recognizable. All newly named clades are diagnosed with small subunit 8 ribosomal RNA (18S rRNA) sequence signatures plus morphological synapomorphies 9 10 where possible. The two major molecular clades are given the rank of order, as 11 Acytosteliales ord. nov. and Dictyosteliales. The two major clades within each of these 12 13 orders are recognized and given the rank of family as, respectively, Acytosteliaceae and 14 15 Cavenderiaceae fam. nov. in Acytosteliales, and Dictyosteliaceae and Raperosteliaceae 16 fam. nov. in Dictyosteliales. Twelve genera are recognized: Cavenderia gen. nov. in 17 18 Cavenderiaceae, Acytostelium, Rostrostelium gen. nov. and Heterostelium gen. nov. in 19 Acytosteliaceae, Tieghemostelium gen. nov., Hagiwaraea gen. nov., Raperostelium gen. 20 21 nov. and Speleostelium gen. nov. in Raperosteliaceae, and Dictyostelium and 22 Polysphondylium in Dictyosteliaceae. The “polycephalum” complex is treated as 23 24 Coremiostelium gen. nov. (not assigned to family) and the “polycarpum” complex as 25 Synstelium gen. nov. (not assigned to order and family). Coenonia, which may not be a 26 27 dictyostelid, is treated as a genus incertae sedis. Eighty-eight new combinations are 28 29 made at species and variety level, and Dictyostelium ammophilum is validated. 30 31 32 33 Key words: Classification; dictyostelids; molecular characters; nomenclature; phylogeny; 34 taxonomy. 35 36 37 38 39 Introduction 40 41 42 Dictyostelids are heterotrophic amoebae, also known informally as cellular slime molds or 43 44 social amoebae. They are commonly isolated from a variety of soils worldwide and are 45 46 ecologically important as predators of soil bacteria. Dictyostelids are particularly well known 47 and widely studied because of their lifestyle, which alternates regularly between unicellular 48 49 and multicellular (sorocarpic) stages. This “aggregative multicellular” behaviour has also led 50 to their widespread use as molecular and evolutionary models, beginning largely with 51 52 Dictyostelium discoideum but now including a handful of taxa from across the phylogeny 53 (Singh et al. 2015). The identification and taxonomy of dictyostelids has traditionally been 54 55 56 57 58 59 60 61 62 63 64 65 1 2 based on the morphology of their sorocarps and related characters, as their amoebae appear to 3 4 be indistinguishable. While new species continue to be identified based on morphological 5 characters (e.g. Cavender et al. 2016), molecular phylogeny indicates that much of the 6 7 traditional taxonomy is fundamentally flawed, particularly at the deepest taxonomic levels. 8 Therefore, major taxonomic revision has been needed for some time. 9 10 11 The first dictyostelid was isolated and described by Oskar Brefeld as 12 Dictyostelium mucoroides (Brefeld 1869), the genus name from the Greek “dictyon” (net) and 13 14 “stele” (column) referring to the net-like appearance of the cells in the stalks of the 15 fructifications (sorocarps). By the end of the 19th century three further species of 16 17 Dictyostelium had been described, D. lacteum and D. roseum by van Tieghem (1880), and D. 18 sphaerocephalum by Saccardo and Marchal (Marchal 1885), the latter based on Hyalostilbum 19 20 sphaerocephalum (Oudemans 1885). Two new genera were also added, Coenonia with the 21 C. denticulata Polysphondylium 22 single species (van Tieghem 1884) and with the single 23 species P. violaceum (Brefeld 1884). Coenonia was characterized, in part, by the crampon- 24 25 shaped base of the stalks and by the cupule-like structure containing the spores, whereas 26 Polysphondylium was characterized, above all, by whorls of regularly spaced side branches on 27 28 the main axial stalk of the sorocarp. In 1900 dictyostelids were known from Europe only, but 29 since then well over a hundred species of Dictyostelium and more than 30 species of 30 31 Polysphondylium have been described from all over the world (see Raper 1984 for an 32 excellent summary of the period up to then). In addition, one further genus was added, 33 34 Acytostelium (Raper 1956), characterized mainly by the acellular stalks of the sorocarps. This 35 36 differs from all other dictyostelids, in which a substantial portion of the aggregate is sacrificed 37 to form a stalk composed of dead cells. Acytostelium has 16 described species to date, and 38 39 new species of Dictyostelium, Polysphondylium and Acytostelium are being added 40 continuously. However, the enigmatic Coenonia denticulata was lost and never recollected 41 42 (Raper 1984) and the genus remains monospecific, with no available material. 43 44 During the last 15 years, increasingly refined cladistic analyses (Swanson et al. 45 46 2002) together with molecular phylogenetics (Romeralo et al. 2007, 2011; Schaap et al. 2006; 47 Sheikh et al. 2014; Singh et al. 2016) have shown that the traditional, morphology-based 48 49 taxonomy of the dictyostelids does not reflect phylogenetic relationships. Instead of three 50 genera, eight distinct molecular clades have been consistently and robustly identified based 51 52 primarily on well-resolved small subunit ribosomal RNA (SSU rRNA) trees (Romeralo et al. 53 2011; Schaap et al. 2006). Where tested, these relationships have also been confirmed by 54 55 56 57 58 59 60 61 62 63 64 65 1 2 cladistics analysis of morphological characters (Swanson et al. 2002) and/or molecular 3 4 phylogeny based on alpha-tubulin (atub) and atub + SSU rRNA (Schaap et al. 2006), 5 internally transcribed spacer (ITS) + 5.8S rRNA (Romeralo et al. 2007), ITS + SSU rRNA 6 7 (Romeralo et al. 2011), and multi-protein phylogeny (Romeralo et al. 2013; Sheikh et al. 8 2015; Singh et al. 2016). 9 10 11 Most importantly, none of the eight main molecular clades correspond to 12 traditional genera. Until now, these clades have been informally denoted as Groups 1, 2A, 2B, 13 14 3, and 4, plus complexes “polycarpum”, “polycephalum”, and “violaceum”, with the three 15 traditional morphotypes distributed across them. Thus, traditional species of Dictyostelium 16 17 (dictyostelid morphotypes) are found in Groups 1, 2B, 3 and 4, and in the “polycarpum”, 18 “polycephalum”, and “violaceum” complexes, while traditional species of Polysphondylium 19 20 (polysphondylid morphotypes) are found in Group 2B and the “violaceum” complex, and 21 Acytostelium 22 species of (acytostelid morphotypes) in Groups 2A and 2B (Romeralo et al. 23 2007; Schaap et al. 2006) or even deeper in the tree (Singh et al. 2016). 24 25 Our aim here is to present, on the basis of existing nomenclature, a new 26 27 classification of the dictyostelids at the levels of order, family and genus. With the exception 28 of the root, the taxonomy is based on monophyletic entities that are strongly and consistently 29 30 reproduced by small subunit ribosomal RNA (SSU rRNA) phylogenies and not contradicted 31 32 by any other molecular data (Supplementary Material Fig. S1; Romeralo et al. 2011; Schaap 33 et al. 2006). SSU rRNA phylogeny is essential for this as it is the only data available for the 34 35 vast majority of dictyostelid species. However, all major groups have been confirmed where 36 tested by other molecular data, specifically SSU ITS + 5.8S (Romeralo et al. 2007), and atub 37 38 and atub+SSU rRNA (Schaap et al. 2006), and mitochondrial genes (Heidel et al. 2008). The 39 taxa proposed here are, as far as possible, also morphologically recognizable. The position of 40 41 the root of the dictyostelid tree (between Groups 1+2 and 3+4), while not well resolved by 42 SSU rRNA (Schaap et al. 2006), is strongly and consistently supported by three distinct multi- 43 44 protein studies (Romeralo et al. 2011; Sheikh et al. 2014; Singh et al. 2016). 45 46 Given the dearth of morphological synapormorphies for many dictyostelid 47 48 groups, all new taxa are also diagnosed with sequence signatures based on SSU rRNA, the 49 most widely used taxonomic molecular marker for eukaryotes and the only marker available 50 51 for most dictyostelids. The approach here is conservative, and there is considerable potential 52 53 for further taxonomic subdivision. Taxonomic problems at species level, such as the many 54 55 56 57 58 59 60 61 62 63 64 65 1 2 instances of morphologically similar but phylogenetically distinct taxa (cryptic species) 3 4 scattered throughout the dictyostelid tree (Mehdaibadi et al. 2009; Romeralo et al. 2011), are 5 not dealt with here. However, the new classification is also meant to be a framework for 6 7 future work at the species level. 8 9 10 11 Results 12 13 14 15 We propose that the two major clades in the phylogeny of the dictyostelids (Fig. 1) are given 16 the rank of order, as Acytosteliales ord. nov. (molecular groups 1, 2A and 2B) and 17 18 Dictyosteliales (molecular groups 3, 4 and molecular complexes “polycephalum” and 19 violaceum 20 “ ”). We further propose that the two major clades within each order are given the 21 rank of family, as Acytosteliaceae and Cavenderiaceae fam. nov. in Acytosteliales and 22 23 Dictyosteliaceae and Raperosteliaceae fam. nov. in Dictyosteliales (Fig. 1). The 24 “polycephalum” complex, with a still contentious position within Dictyosteliales, is not 25 26 assigned to family, and the “polycarpum” complex, with a still contentious position in the 27 entire phylogeny, is not assigned to either order or family. 28 29 30 Twelve taxa are recognized at the genus level (Fig. 1), Cavenderia gen. nov. 31 corresponding to Group 1, Acytostelium corresponding to Group 2A, Rostrostelium gen. nov. 32 33 currently including only Acytostelium ellipticum in Group 2B, Heterostelium gen. nov. 34 corresponding to the remainder of Group 2B excluding Acytostelium ellipticum, Speleostelium 35 36 gen. nov. currently including only Dictyostelium caveatum, Tieghemostelium gen. nov. 37 corresponding to Group 3A, Hagiwaraea gen. nov. corresponding to Group 3B, 38 39 Raperostelium gen. nov. corresponding to Group 3C, Dictyostelium corresponding to Group 40 Coremiostelium polycephalum Polysphondylium 41 4, gen. nov. corresponding to the “ ” complex, 42 corresponding to the “violaceum” complex, and Synstelium gen. nov. corresponding to the 43 44 “polycarpum” complex. The enigmatic Coenonia is treated as a genus incertae sedis. 45 46 47 48 Taxonomy 49 50 Acytosteliales S.Baldauf, S.Sheikh & Thulin, ord. nov. (Index Fungorum ID IF553650). 51 Type: Acytostelium Raper 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Diagnosis: New order comprising the two families Acytosteliaceae and Cavenderiaceae, 3 4 which differs from Dictyosteliales and the unplaced genus Synstelium together by having in 5 the SSU rRNA gene C (not T) in the nucleotide position 539 and CTC (not CTA) in the 6 7 positions 1448-1450 of Supplementary Material alignment S2 (Figs 2, 3A). 8 Description: Sorocarps with cellular or acellular stalks, colorless, white-hyaline or pale 9 10 yellow, solitary or loosely to tightly clustered, branching rare and usually sparse or irregular 11 where it occurs, sometimes with regularly spaced branches, the sorogens sometimes 12 13 ventricose-rostrate. Spores globose to irregularly rounded or ellipsoid, sometimes oblong or 14 15 reniform in outline, granules present or absent. Microcysts and macrocysts sometimes present. 16 Streaming aggregation, slug migration rare, sometimes stalked, acrasin glorin or mostly 17 18 unknown. 19 20 21 22 Acytosteliaceae Raper ex Raper & Quinlan, J. Gen. Microbiol. 18: 18 (1958). Type: 23 Acytostelium Raper 24 25 Family comprising three genera, Acytostelium, Rostrostelium and Heterostelium. 26 Description: Sorocarps with cellular or acellular stalks, colorless or white hyaline, solitary or 27 28 loosely to tightly clustered, branching rare and usually sparse where it occurs, sometimes with 29 regularly spaced branches, the sorogens sometimes ventricose-rostrate. Spores globose to 30 31 irregularly rounded or ellipsoid, granules present or absent. Microcysts and macrocysts 32 sometimes present. Streaming aggregation, slug migration rare, sometimes stalked, acrasin 33 34 glorin or mostly unknown. 35 36 37 38 Acytostelium Raper, Mycologia 48: 179 (1956). Type: Acytostelium leptosomum Raper (Fig. 39 4) 40 41 Description: Sorocarps with acellular stalks, colorless, solitary to loosely clustered 42 (gregarious), slender and delicate, 0.2-3.0 mm in height, branching rare and sparse 43 44 where it occurs. Spores globose, subglobose or irregularly rounded, 4.0-8.5 µm in 45 46 diameter, granules rare or inconspicuous. Microcysts known, macrocysts unknown. 47 Streaming aggregation, slug migration rare, acrasin unknown. 48 49 50 Acytostelium aggregatum Cavender & Vadell, Mycologia 92: 1004 (2000) 51 52 Acytostelium amazonicum 53 Cavender & Vadell, Mycologia 92: 995 (2000) 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Acytostelium anastomosans Cavender et al., Mycologia 97: 497 (2005) 3 4 Acytostelium digitatum Cavender & Vadell, Mycologia 92: 997 (2000) 5 6 7 Acytostelium irregularosporum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo 14: 364 (1971) 8 9 Acytostelium leptosomum Raper, Mycologia 48: 179 (1956) 10 11 Acytostelium longisorophorum Cavender et al., Mycologia 97: 498 (2005) 12 13 14 Acytostelium magniphorum Cavender & Vadell, Mycologia 92: 1000 (2000) 15 16 Acytostelium magnisorum Cavender et al., Mycologia 97: 499 (2005) 17 18 Acytostelium minutissimum Cavender & Vadell, Mycologia 92: 1002 (2000) 19 20 Acytostelium pendulum 21 Cavender & Vadell, Mycologia 92: 1001 (2000) 22 23 Acytostelium reticulatum Cavender & Vadell, Mycologia 92: 998 (2000) 24 25 Acytostelium serpentarium Cavender et al., Mycologia 97: 500 (2005) 26 27 Acytostelium singulare Cavender et al., Mycologia 97: 501 (2005) 28 29 30 Acytostelium subglobosum Cavender, Amer. J. Bot. 63: 61 (1976) 31 32 33 34 Rostrostelium S.Baldauf, S.Sheikh & Thulin, gen. nov. (Index Fungorum IF553651). Type: Formatted: Swedish (Sweden) 35 Rostrostelium ellipticum (Cavender) S.Baldauf, S.Sheikh & Thulin (Fig. 5) 36 37 Diagnosis: New genus similar to Acytostelium in having sorocarps with a simple acellular 38 stalk, but differing from all species of this genus by its ellipsoid (not globose, subglobose or 39 40 irregularly rounded) spores. Differs from Heterostelium by having sorocarps with an acellular 41 Acytostelium Heterostelium 42 stalk and from both and by having ventricose-rostrate sorogens 43 and by having in the SSU rRNA gene ATGG (not CAAG, CAGA, AAGA, TAGA) in the 44 45 nucleotide positions 133-136 and TAATTA (not CAATTT, AAATTG, CAATTG) in 46 positions 540-545 of Supplementary Material alignment S3 (Figs 2, 3B). 47 48 Description: Sorocarps with acellular stalks, solitary or gregarious, delicate, 49 unbranched, 0.2-1.0 mm in height, colorless, the sorogens ventricose-rostrate. Spores 50 51 ellipsoid, 5.0-6.0 × 2.5-3.0 µm, polar granules rare. Microcysts known, macrocysts 52 unknown. Streaming aggregation, slug migration stalked, acrasin unknown. 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Etymology: “Rostro-” in the name alludes to the characteristically rostrate (beaked) sorogens 3 4 of this genus. 5 6 Rostrostelium ellipticum (Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 7 Acytostelium ellipticum 8 Fungorum IF553652). Cavender, J. Gen. Microbiol. 62: 119 (1970) 9 10 11 12 Heterostelium S.Baldauf, S.Sheikh & Thulin, gen. nov. (Index Fungorum IF553653). Type: 13 14 Heterostelium pallidum (Olive) S.Baldauf, S.Sheikh & Thulin (Fig. 6) 15 Diagnosis: New genus related to Acytostelium and Rostrostelium, from both of which it 16 17 differs by having sorocarps with a cellular stalk and by having in the SSU rRNA gene AGG 18 (not CGG) in the nucleotide positions 364-366 and GGG (not GAG) in the positions 535-537 19 20 of Supplementary Material alignment S4 (Fig. 2, 3C). 21 22 Description: Sorocarps with cellular stalks, white-hyaline, solitary or loosely to 23 tightly clustered, unbranched or sparsely branched or with whorls of regularly spaced 24 25 branches, small and often delicate, mostly <10 mm in height (range 0.2-15 mm). 26 Spores highly variable, granules present/absent consolidated/unconsolidated, generally 27 28 3.5-8.0 × 2.0-4.0 µm (rarely up to 11.5 × 5.8 µm). Microcysts commonly observed, 29 sometimes also macrocysts. Streaming aggregation, often of violaceum type 30 31 (fragmenting to form separate sorocarps), slug migration stalked when present, acrasin 32 glorin (H. pallidum) or unknown. 33 34 Etymology: The prefix “hetero-” in the name alludes to the great variation in sorocarp 35 36 morphology within this genus. 37 38 Heterostelium album (Olive) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Fungorum 39 40 IF553654). Polysphondylium album Olive, Proc. Amer. Acad. Arts 37: 342 (1901) 41 42 Heterostelium ampliverticillatum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 43 44 (Index Fungorum IF553663). Polysphondylium ampliverticillatum Cavender et al., Mycologia 45 108: 85 (2016) 46 47 Heterostelium anisocaule 48 (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 49 Fungorum IF553664). Polysphondylium anisocaule Cavender et al., New Zealand J. Bot. 40: 50 51 240 (2002) 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Heterostelium arachnoideum (Vadell & Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. 3 4 (Index Fungorum IF553665). Polysphondylium arachnoideum Vadell & Cavender, 5 Mycologia 99: 120 (2007) 6 7 Heterostelium asymetricum 8 (Vadell & Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. 9 (Index Fungorum IF553666). Polysphondylium asymetricum Vadell & Cavender, Mycologia 10 11 90: 719 (1998). 12 13 Heterostelium australicum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 14 Fungorum IF553667). Polysphondylium australicum Cavender et al., Austral. Syst. Bot. 21: 15 16 60 (2008) 17 18 Heterostelium boreale (Romeralo et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 19 20 Fungorum IF553668). Dictyostelium boreale Romeralo et al., Mycologia 102: 592 (2010) 21 22 Heterostelium candidum (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 23 24 Fungorum IF553669). Polysphondylium candidum H.Hagiw., Rep. Tottori Mycol. Inst. 10: 25 591 (1973) 26 27 28 Heterostelium colligatum (Vadell & Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. 29 (Index Fungorum IF553670). Polysphondylium colligatum Vadell & Cavender, Mycologia 30 31 90: 719 (1998) 32 33 Heterostelium cumulocystum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 34 35 (Index Fungorum IF553671). Polysphondylium cumulocystum Cavender et al., Mycologia 36 108: 87 (2016) 37 38 Heterostelium equisetoides (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 39 40 (Index Fungorum IF553672). Polysphondylium equisetoides Cavender et al., Syst. Geogr. Pl. 41 42 74: 248 (2004) 43 44 Heterostelium filamentosum (F.Traub et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 45 Fungorum IF553673). Polysphondylium filamentosum F.Traub et al., Amer. J. Bot. 68: 169 46 47 (1981) 48 49 Heterostelium flexuosum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 50 51 Fungorum IF553674). Dictyostelium flexuosum Cavender et al., Austral. Syst. Bot. 21: 51 52 (2008) 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Heterostelium gloeosporum (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 3 4 Fungorum IF553675). Dictyostelium gloeosporum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 5 29: 127 (2003) 6 7 Heterostelium granulosum 8 (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 9 Fungorum IF553676). Dictyostelium granulosum Cavender et al., Austral. Syst. Bot. 21: 55 10 11 (2008) 12 13 Heterostelium lapidosum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 14 Fungorum IF553677). Polysphondylium lapidosum Cavender et al., Mycologia 108: 88 15 16 (2016) 17 18 Heterostelium luridum (G.Kauffm. et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 19 Polysphondylium luridum 20 Fungorum IF553678). G.Kauffm. et al., Bot. Helv. 98: 125 (1988) 21 Heterostelium migratissimum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 22 23 (Index Fungorum IF553679). Polysphondylium migratissimum Cavender et al., Mycologia 24 108: 89 (2016) 25 26 Heterostelium multicystogenum (S.Kawak. & H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, 27 comb. nov. (Index Fungorum IF553680). Polysphondylium multicystogenum S.Kawak. & 28 H.Hagiw., Mycologia 100: 347 (2008) 29 30 Heterostelium naviculare (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 31 Fungorum IF553681). Dictyostelium naviculare Cavender et al., Mycologia 97: 504 (2005) 32 33 Heterostelium oculare (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 34 Fungorum IF553682). Dictyostelium oculare Cavender et al., Mycologia 97: 505 (2005) 35 36 Heterostelium pallidum (Olive) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Fungorum 37 38 IF553683). Polysphondylium pallidum Olive, Proc. Amer. Acad. Arts 37: 341 (1901) 39 Heterostelium parvimigratum 40 (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 41 (Index Fungorum IF553684). Polysphondylium parvimigratum Cavender et al., Mycologia 42 108: 90 (2016) 43 44 Heterostelium perasymmetricum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 45 (Index Fungorum IF553685). Polysphondylium perasymmetricum Cavender et al., Mycologia 46 108: 91 (2016) 47 48 Heterostelium plurimicrocystogenum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. 49 nov. (Index Fungorum IF553686). Polysphondylium plurimicrocystogenum Cavender et al., 50 51 Mycologia 108: 92 (2016) 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Heterostelium pseudocandidum (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 3 Fungorum IF553687). Polysphondylium pseudocandidum H.Hagiw., Bull. Natl. Sci. Mus., 4 Tokyo, B 5: 67 (1979) 5 6 Heterostelium pseudocolligatum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 7 8 (Index Fungorum IF553688). Polysphondylium pseudocolligatum Cavender et al., Mycologia 9 108: 94 (2016) 10 11 Heterostelium pseudoplasmodiofascium (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, 12 comb. nov. (Index Fungorum IF553689). Polysphondylium pseudoplasmodiofascium 13 Cavender et al., Mycologia 108: 96 (2016) 14 15 Heterostelium pseudoplasmodiomagnum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, 16 comb. nov. (Index Fungorum IF553690). Polysphondylium pseudoplasmodiomagnum 17 Cavender et al., Mycologia 108: 97 (2016) 18 19 Heterostelium racemiferum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 20 21 (Index Fungorum IF553691). Polysphondylium racemiferum Cavender et al., Mycologia 108: 22 98 (2016) 23 24 Heterostelium rotatum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 25 Fungorum IF553692). Dictyostelium rotatum Cavender et al., Austral. Syst. Bot. 21: 60 26 (2008) 27 28 Heterostelium stolonicoideum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 29 (Index Fungorum IF553693). Polysphondylium stolonicoideum Cavender et al., Austral. Syst. 30 Bot. 21: 62 (2008) 31 32 Heterostelium tenuissimum (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 33 34 Fungorum IF553694). Polysphondylium tenuissimum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, 35 B 5: 69 (1979) 36 37 Heterostelium tikalense (Vadell & Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. 38 (Index Fungorum IF553695). Polysphondylium tikalense Vadell & Cavender, Mycologia 90: 39 721 (1998), as “tikaliensis” 40 41 Heterostelium unguliferum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 42 (Index Fungorum IF553696). Polysphondylium unguliferum Cavender et al., Mycologia 108: 43 99 (2016) 44 45 Heterostelium violaceotypum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 46 47 (Index Fungorum IF553697). Polysphondylium violaceotypum Cavender et al., Mycologia 48 108: 100 (2016) 49 50 51 52 Cavenderiaceae S.Baldauf, S.Sheikh & Thulin, fam. nov. (Index Fungorum IF553754). 53 Type: Cavenderia S.Baldauf, S.Sheikh & Thulin 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Diagnosis: New monogeneric family, sister group of Acytosteliaceae, from which it differs 3 4 by having in the SSU rRNA gene GT (not AA) in the nucleotide positions 471-472 and CAT 5 (not AGA) in the positions 907-909 of Supplementary Material alignment S5 (Figs 2, 3D). 6 7 Description: Sorocarps with cellular stalks, solitary to loosely or (rarely) tightly clustered, 8 unbranched or irregularly branched, white-hyaline or pale yellow. Spores oblong to elliptic or 9 10 reniform in outline, with consolidated polar or subpolar granules. Microcysts and macrocysts 11 sometimes present. Streaming aggregation, slug migration stalked or stalkless, acrasin 12 13 unknown. 14 15 16 17 18 Cavenderia S.Baldauf, S.Sheikh & Thulin, gen. nov. (Index Fungorum IF553698). Type: 19 20 Cavenderia fasciculata (F.Traub et al.) S.Baldauf, S.Sheikh & Thulin (Fig. 7) 21 Acytostelium Rostrostelium Heterostelium 22 Diagnosis: New genus, sister group of , and 23 together, from all of which it differs by having in the SSU rRNA gene GT (not AA) in the 24 25 nucleotide positions 482-483 and CAT (not AGA) in the positions 916-918 of Supplementary 26 Material alignment S5 (Figs 2, 3D). 27 28 Description: Sorocarps with cellular stalks, solitary to loosely or (rarely) tightly 29 clustered, unbranched or irregularly branched, white-hyaline or pale yellow, mostly 30 31 0.2-7 mm high (rarely up to 1 cm). Spores 3.0-8.0 × 1.5-4.0 µm, oblong to elliptic or 32 reniform in outline, with consolidated polar or subpolar granules. Microcysts and 33 34 macrocysts sometimes present. Streaming aggregation, slug migration stalked or 35 36 stalkless, acrasin unknown. 37 Etymology: Named after James C. Cavender, Ohio University, Athens, since the 1960ʼs the 38 39 author of numerous species of dictyostelids from all over the world and the leading expert in 40 the field. 41 42 Cavenderia amphispora (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 43 44 Fungorum IF553699). Dictyostelium amphisporum Cavender et al., Mycologia 97: 503 (2005) 45 46 Cavenderia antarctica (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 47 48 Fungorum IF553700). Dictyostelium antarcticum Cavender et al., New Zealand J. Bot. 40: 49 245 (2002) 50 51 52 Cavenderia aureostipes (Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 53 Fungorum IF553701). Dictyostelium aureostipes Cavender, Amer. J. Bot. 66: 209 (1979) 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Cavenderia aureostipes (Cavender) S.Baldauf, S.Sheikh & Thulin var. helvetia (Cavender et 3 4 al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Fungorum IF553655). Dictyostelium 5 aureostipes Cavender var. helvetium Cavender et al., Amer. J. Bot. 66: 209 (1979) 6 7 Cavenderia bifurcata 8 (Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 9 Fungorum IF553702). Dictyostelium bifurcatum Cavender, Amer. J. Bot. 63: 66 (1976) 10 11 Cavenderia boomerangispora (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 12 13 (Index Fungorum IF553703). Dictyostelium boomerangisporum Cavender et al., Austral. 14 Syst. Bot. 21: 51 (2008), as “boomeransporum” 15 16 17 Cavenderia delicata (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Fungorum 18 IF553704). Dictyostelium delicatum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo 14: 359 (1971) 19 20 21 Cavenderia deminutiva (J.S.Anderson et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 22 (Index Fungorum IF553705). Dictyostelium deminutivum J.S.Anderson et al., Mycologia 60: 23 24 51 (1968) 25 26 Cavenderia exigua (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Fungorum 27 28 IF553706). Dictyostelium exiguum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 9: 149 (1983) 29 30 Cavenderia fasciculata (F.Traub et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Formatted: German (Germany) 31 Fungorum IF553707). Dictyostelium fasciculatum F.Traub et al., Amer. J. Bot. 68: 166 (1981) 32 33 34 Cavenderia fasciculoidea (Vadell et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 35 Fungorum IF553708). Dictyostelium fasciculoideum Vadell et al., Mycologia 103: 107 (2011) 36 37 38 Cavenderia granulophora (Vadell et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 39 Fungorum IF553709). Dictyostelium granulophorum Vadell et al., Mycologia 87: 557 (1995) 40 41 Cavenderia macrocarpa 42 (Vadell & Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. 43 (Index Fungorum IF553710). Dictyostelium macrocarpum Vadell & Cavender, Mycologia 99: 44 45 113 (2007) 46 47 Cavenderia medusoides (Vadell et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 48 Dictyostelium medusoides 49 Fungorum IF553711). Vadell et al., Mycologia 87: 555 (1995) 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Cavenderia mexicana (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 3 4 Fungorum IF553712). Dictyostelium mexicanum Cavender et al., Amer. J. Bot. 68: 379 5 (1981) 6 7 Cavenderia microspora 8 (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 9 Fungorum IF553713). Dictyostelium microsporum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 10 11 4: 27 (1978) 12 13 Cavenderia multistipes (Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 14 Fungorum IF553714). Dictyostelium multistipes Cavender, Amer. J. Bot. 63: 63 (1976) 15 16 17 Cavenderia myxobasis (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 18 Fungorum IF553715). Dictyostelium myxobasis Cavender et al., Austral. Syst. Bot. 21: 56 19 20 (2008) 21 22 Cavenderia nanopodium (Vadell & Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. 23 24 (Index Fungorum IF553716). Dictyostelium nanopodium Vadell & Cavender, Mycologia 99: 25 118 (2007) 26 27 28 Cavenderia parvispora (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 29 Fungorum IF553717). Dictyostelium parvisporum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 30 31 12: 99 (1986) 32 33 Cavenderia stellata (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 34 35 Fungorum IF553718). Dictyostelium stellatum Cavender et al., Mycologia 97: 508 (2005) 36 37 38 39 Dictyosteliales L.S.Olive ex P.M.Kirk et al., Ainsworth & Bisbyʼs Dictionary of the Fungi, 40 41 ed. 9: x (2001). Type: Dictyostelium Bref. 42 Order comprising the two families Dictyosteliaceae and Raperosteliaceae, and the genus 43 44 Coremiostelium not assigned to family. 45 46 Description: Sorocarps with cellular stalks, sometimes with acellular apical stretches, 47 sometimes with crampon-shaped bases, colorless or with white to pale yellow or purple sori, 48 49 solitary or clustered, unbranched, irregularly branched or sometimes with regularly spaced 50 whorls of branches or coremiform. Spores mostly elliptic or oblong in outline, sometimes 51 52 globose, granules present or absent. Microcysts and macrocysts sometimes present. Streaming 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 or non-streaming aggregation, slug migration present or absent, sometimes stalked, acrasin 3 4 cAMP, glorin, folate, pterin or unknown. 5 6 7 Dictyostelium 8 Dictyosteliaceae Rostaf. ex Cooke, Contr. Mycol. Brit.: 53 (1877). Type: Bref. 9 Family comprising two genera, Dictyostelium and Polysphondylium. 10 11 Description: Sorocarps with cellular stalks, colorless or with white to pale yellow sori, 12 solitary or clustered, unbranched, irregularly branched, with regularly spaced whorls of 13 14 branches or coremiform. Spores elliptic or oblong in outline, granules present or absent. 15 Microcysts rare macrocysts more common. Streaming aggregation, slug migration present or 16 17 absent, sometimes stalked, acrasin cAMP, glorin or unknown. 18 19 20 Dictyostelium Bref., Abh. Senckenberg. Naturf. Ges. 7: 85 (1869). Type: Dictyostelium Formatted: Swedish (Sweden) 21 22 mucoroides Bref. (Fig. 8) 23 = Hyalostilbum Oudem., Ned. Kruidk. Arch., ser. 2, 4: 241 (1885). Type: Hyalostilbum 24 25 sphaerocephalum Oudem. 26 27 Description: Sorocarps with cellular stalks, colorless or with white to pale yellow 28 sori, mostly solitary but sometimes clustered, mostly unbranched but sometimes with 29 30 irregular branches, generally 3-7 mm in height but >1 cm common (range 1.5-43.0 31 mm), often with a basal support disk. Spores mostly elliptic or sometimes oblong in 32 33 outline, polar granules mostly absent and unconsolidated where present, commonly 34 4.0-9.0 × 2.0-5.0 µm (range 3.0-26.0 ×2.0-7.5 µm). Microcysts rarely observed, 35 36 macrocysts more common. Streaming aggregation, slug migration stalked or stalkless 37 when present, acrasin cAMP or unknown (likely cAMP). 38 39 40 Dictyostelium ammophilum 41 Romeralo et al. ex S.Baldauf, S.Sheikh & Thulin, sp. nov. (Index 42 Fungorum IF553657). Holotype: U.S.A., Alaska, isolate NW2B, Landolt #864 (stored in 43 44 liquid nitrogen at the Dicty Stock Center, strain ID DBS0349823) 45 Note on typification: Dictyostelium ammophilum was described and illustrated by Romeralo 46 47 et al. in Mycologia 102: 590 (2010), and the isolate NW2B, Landolt #864 was cited as 48 holotype. However, in p. 592 of this paper Romeralo et al. state that this isolate “will be 49 50 deposited at the American Type Culture Collection (ATCC) and/or the Dicty Stock Center”. 51 This is contrary to ICN Art. 40.7 (McNeill et al. 2012), which states that for valid publication 52 53 of names of new species published after 1 January 1990 “the single herbarium or collection or 54 55 56 57 58 59 60 61 62 63 64 65 1 2 institution in which the type is conserved must be specified”. We therefore here validate D. 3 4 ammophilum by designation of the isolate in Dicty Stock Center strain ID DBS0349823 as 5 holotype. 6 7 Dictyostelium aureocephalum 8 H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 17: 103 (1991) 9 10 Dictyostelium aureum Olive, Proc. Amer. Acad. Arts 37: 340 (1901) 11 12 Dictyostelium aureum Olive var. luteolum Cavender et al., Amer. J. Bot. 68: 376 (1981) 13 14 Dictyostelium austroandinum Vadell et al., Mycologia 103: 103 (2011) 15 16 17 Dictyostelium barbibulus Perrigo & Romeralo, Fung. Diversity 58: 191 (2013) 18 19 Dictyostelium brefeldianum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 10: 39 (1984) 20 21 Dictyostelium brevicaule Olive, Proc. Amer. Acad. Arts 37: 340 (1901) 22 23 24 Dictyostelium brunneum Kawabe, Trans. Mycol. Soc. Japan 23: 91 (1982) 25 26 Dictyostelium capitatum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 9: 45 (1983) 27 28 Dictyostelium chordatum Vadell et al., Mycologia 103: 105 (2011) 29 30 31 Dictyostelium citrinum Vadell et al., Mycologia 87: 553 (1995) 32 33 Dictyostelium clavatum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 18: 1 (1992) 34 35 Dictyostelium crassicaule H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 10: 67 (1984) 36 37 Dictyostelium dimigraformum 38 Cavender, J. Gen. Microbiol. 62: 115 (1970) 39 40 Dictyostelium discoideum Raper, J. Agric. Res. 50: 135 (1935) Formatted: German (Germany) 41 42 Dictyostelium firmibasis H.Hagiw., Bull. Natl. Sci. Mus., Tokyo 14: 356 (1971) 43 44 Dictyostelium gargantuum Vadell et al., Mycologia 103: 108 (2011) 45 46 47 Dictyostelium giganteum B.N.Singh, J. Gen. Microbiol. 1: 17 (1947) Formatted: Swedish (Sweden) 48 49 Dictyostelium implicatum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 10: 63 (1984) 50 51 Dictyostelium intermedium Cavender, Amer. J. Bot. 63: 63 (1976) 52 53 54 Dictyostelium leptosomopsis Vadell et al., Mycologia 103: 110 (2011) 55 56 57 58 59 60 61 62 63 64 65 1 2 Dictyostelium leptosomum Cavender et al., New Zealand J. Bot. 40: 252 (2002) Formatted: Swedish (Sweden) 3 4 Dictyostelium longosporum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 9: 55 (1983) 5 6 7 Dictyostelium macrocephalum H.Hagiw. et al., Bull. Natl. Sci. Mus., Tokyo, B 11: 104 8 (1985) 9 10 Dictyostelium medium 11 H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 18: 4 (1992) 12 13 Dictyostelium mucoroides Bref., Abh. Senckenberg. Naturf. Ges. 7: 85 (1869) Formatted: German (Germany) 14 15 Dictyostelium mucoroides Bref. var. stoloniferum Cavender & Raper, Amer. J. Bot. 55: 510 16 17 (1968) 18 19 Dictyostelium pseudobrefeldianum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 22: 47 (1996) 20 21 Dictyostelium purpureum Olive, Proc. Amer. Acad. Arts 37: 340 (1901) 22 23 24 Dictyostelium quercibrachium Cavender et al., New Zealand J. Bot. 40: 258 (2002) 25 26 Dictyostelium robustum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 22: 51 (1996) 27 28 Dictyostelium rosarium Raper & Cavender, J. Elisha Mitchell Sci. Soc. 84: 31 (1968) 29 30 31 Dictyostelium septentrionale Cavender, Canad. J. Bot. 56: 1329 (1978), as “septentrionalis” 32 33 Dictyostelium sphaerocephalum (Oudem.) Sacc. & Marchal, Bull. Soc. Roy. Bot. Belgique 34 24: 74 (1885). Hyalostilbum sphaerocephalum Oudem., Ned. Kruidk. Arch., ser. 2, 4: 241 35 36 (1885) 37 38 Dictyostelium valdivianum Vadell et al., Mycologia 103: 111 (2011) 39 40 41 42 Polysphondylium Bref., Untersuch. Gesammt. Mycol. 6: 5 (1884). Type: Polysphondylium Formatted: German (Germany) 43 44 violaceum Bref. (Fig. 9) 45 Description: Sorocarps with cellular stalks and sori pigmented violet/lavender/purple 46 47 often darkening with age, whorls of branches regularly or irregularly spaced, clustered 48 or solitary, height 1-20 mm. Spores mostly ellipsoid with polar granules often 49 50 consolidated, 5.0-12.5 × 2.5-5.0 µm. Macrocysts sometimes observed, microcysts 51 52 unknown. Streaming aggregation, slug migration stalked when present, acrasin glorin 53 or unknown. 54 55 56 57 58 59 60 61 62 63 64 65 1 2 3 4 Polysphondylium fuscans Perrigo & Romeralo, Fung. Diversity 58: 192 (2012) 5 6 Polysphondylium laterosorum (Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 7 Dictyostelium laterosorum 8 Fungorum IF553719). Cavender, J. Gen. Microbiol. 62: 117 9 (1970) 10 11 Polysphondylium patagonicum Vadell et al., Mycologia 103: 113 (2011) 12 13 14 Polysphondylium violaceum Bref., Untersuch. Gesammt. Mycol. 6: 5 (1884) Formatted: German (Germany) 15 16 17 18 Raperosteliaceae S.Baldauf, S.Sheikh & Thulin, fam. nov. (Index Fungorum IF553755). 19 20 Type: Raperostelium S.Baldauf, S.Sheikh & Thulin 21 Diagnosis: New family differing from Dictyosteliacae and Coremiostelium by having in the 22 23 SSU rRNA gene CAA (not CGA) in the nucleotide positions 1050-1052 and ATC (not ACC) 24 25 in the positions 1391-1393 of Supplementary Material alignment S6 (Figs 2, 3E). 26 Family comprising four genera, Speleostelium, Tieghemostelium, Hagiwaraea and 27 28 Raperostelium. 29 Description: Sorocarps with cellular stalks, sometimes with acellular apical stretches, 30 31 colorless, solitary or clustered, sometimes with crampon-shaped bases, unbranched or with 32 irregularly spaced branches. Spores ellipsoid to globose or oblong, granules present or absent. 33 34 Microcysts sometimes present, macrocysts rare or unknown. Non-streaming or streaming 35 aggregation, slug migration present or absent, sometimes stalked, acrasin glorin, folate, pterin 36 37 or unknown. 38 39 40 41 Speleostelium S.Baldauf, S.Sheikh & Thulin, gen. nov. (Index Fungorum IF553748). Type: 42 Speleostelium caveatum (Waddell et al.) S.Baldauf, S.Sheikh & Thulin (Fig. 10) 43 44 Diagnosis: New genus, sister to Tieghemostelium, Hagiwaraea and Raperostelium together, 45 46 differing from all of them by having in the SSU rRNA gene GCA (not TTT) in the nucleotide 47 positions 201-203 and CG (not TA) in the positions 1093-1094 of Supplementary Material 48 49 alignment S7 (Figs 2, 11A). 50 Description: Sorocarps with cellular stalks, delicate, colorless, typically clustered, 51 52 erect or semi-erect, 3-7 mm high, often tangled. Spores ellipsoid, 2.7 × 7.8 µm, 53 prominent granules usually but not consistently polar. Microcysts and macrocysts 54 55 56 57 58 59 60 61 62 63 64 65 1 2 unknown. Non-streaming aggregation, no slug migration, acrasin glorin. Myxamoebae 3 4 prey upon cells of other dictyostelids and prevent them from fruiting. 5 Etymology: “Speleo-” in the name refers to the fact that the single species known in the 6 7 genus is cave-dwelling. 8 9 10 Speleostelium caveatum (Waddell et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 11 Fungorum IF553720). Dictyostelium caveatum Waddell et al. in Raper, The dictyostelids: 311 12 13 (1984) 14 15 16 17 18 Hagiwaraea S.Baldauf, S.Sheikh & Thulin, gen. nov. (Index Fungorum IF553749). Type: Formatted: German (Germany) 19 Hagiwaraea rhizopodium (Raper & Fennell) S.Baldauf, S.Sheikh & Thulin (Fig. 12) 20 21 Diagnosis: New genus, sister group of Raperostelium, from which it differs by having 22 sorocarps with a crampon-shaped (not simple) base and by having in the SSU rRNA gene 23 24 GTTGGCTCG (not ATTGGTTGC) in the nucleotide positions 866-874 and GAGTA (not 25 CGGTA) in the positions 1462-1466 of Supplementary Material alignment S8 (Figs 2, 11B). 26 27 Description: Sorocarps with cellular stalks, colorless, with digitate crampon-like 28 29 bases, solitary or clustered, typically unbranched or rarely with sparse irregularly 30 spaced branches, mostly delicate, 0.3-7 mm, but reach 1.5 cm in stoloniferous form of 31 32 H. vinaceofusca. Spores generally oblong, with consolidated polar granules (absent in 33 H. vinaceofusca), mostly 5.0-12 ×2.5-4.5 µm. Microcysts commonly observed, 34 35 macrocysts unknown. Streaming aggregation, slug migration stalked, acrasin 36 unknown. 37 38 Etymology: Named after Hiromitsu Hagiwara, Tokyo, author of many species of 39 dictyostelids, particularly from Japan and other Asian countries. 40 41 42 Hagiwaraea coeruleostipes 43 (Raper & Fennell) S.Baldauf, S.Sheikh & Thulin, comb. nov. 44 (Index Fungorum IF553721). Dictyostelium coeruleostipes Raper & Fennell, Amer. J. Bot. 45 46 54: 519 (1967) 47 48 Hagiwaraea lavandula (Raper & Fennell) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 49 Dictyostelium lavandulum 50 Fungorum IF553722). Raper & Fennell, Amer. J. Bot. 54: 519 51 (1967) 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Hagiwaraea radiculata (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 3 4 Fungorum IF553723). Dictyostelium radiculatum Cavender et al., Austral. Syst. Bot. 21: 57 5 (2008) 6 7 Hagiwaraea rhizopodium 8 (Raper & Fennell) S.Baldauf, S.Sheikh & Thulin, comb. nov. 9 (Index Fungorum IF553724). Dictyostelium rhizopodium Raper & Fennell, Amer. J. Bot. 54: 10 11 517 (1967) 12 13 Hagiwaraea vinaceofusca (Raper & Fennell) S.Baldauf, S.Sheikh & Thulin, comb. nov. 14 (Index Fungorum IF553725). Dictyostelium vinaceofuscum Raper & Fennell, Amer. J. Bot. 15 16 54: 522 (1967) 17 18 19 20 Raperostelium S.Baldauf, S.Sheikh & Thulin, gen. nov. (Index Fungorum IF553750). Type: 21 22 Raperostelium minutum (Raper) S.Baldauf, S.Sheikh & Thulin (Fig. 13) 23 Diagnosis: New genus, sister group of Hagiwaraea, from which it differs by having 24 25 sorocarps with a simple (not crampon-shaped) base and by having in the SSU rRNA gene 26 27 ATTGGTTGC (not GTTGGCTCG) in the nucleotide positions 866-874 and CGGTA (not 28 GAGTA) in the positions 1462-1466 of Supplementary Material alignment S9 (Figs 2, 11C). 29 30 Description: Sorocarps with cellular stalks, colorless, solitary or clustered, branches 31 absent to irregularly whorled, delicate, 0.5-7 mm in height, base simple or clavate. 32 33 Spores oblong or elliptic in outline, granules inconsistently present/consolidated/polar, 34 4.0-10.0 × 1.8-5.0 µm, highly variable in some species. Microcysts commonly 35 36 observed, macrocysts known only for R. minutum. Aggregation streaming minor or 37 absent, slug migration present or absent, acrasin folate (R. minutum) or unknown. 38 39 Etymology: Named after Kenneth Bryan Raper (1908-1987), author of “The Dictyostelids” 40 41 (Raper 1984), a landmark in the field, and author of numerous species of dictyostelids, 42 including the type of Raperostelium. 43 44 45 Raperostelium australe (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Formatted: German (Germany) 46 47 Fungorum IF553726). Dictyostelium australe Cavender et al., New Zealand J. Bot. 40: 249 48 (2002) 49 50 51 Raperostelium capillare (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 52 Fungorum IF553727). Dictyostelium capillare Cavender et al., Mycologia 105: 617 (2012) 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Raperostelium filiforme (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 3 4 Fungorum IF553728). Dictyostelium filiforme Cavender et al., Mycologia 105: 619 (2012) 5 6 Raperostelium gracile (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 7 Dictyostelium gracile 8 Fungorum IF553729). H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 9: 150 9 (1983) 10 11 Raperostelium ibericum (Romeralo et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 12 13 Fungorum IF553730). Dictyostelium ibericum Romeralo et al., Mycologia 101: 270 (2009) 14 15 Raperostelium maeandriforme (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 16 17 (Index Fungorum IF553731). Dictyostelium maeandriforme Cavender et al., Mycologia 105: 18 621 (2012) 19 20 21 Raperostelium minutum (Raper) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Fungorum 22 IF553732). Dictyostelium minutum Raper, Mycologia 33: 634 (1941) 23 24 Raperostelium monochasioides 25 (H.Hagiw.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 26 Fungorum IF553733). Dictyostelium monochasioides H.Hagiw., Bull. Natl. Sci. Mus., Tokyo 27 28 16: 494 (1973) 29 30 Raperostelium ohioense (Cavender & Vadell) S.Baldauf, S.Sheikh & Thulin, comb. nov. 31 (Index Fungorum IF553734). Dictyostelium ohioense Cavender & Vadell, Bull. Ohio Biol. 32 33 Surv., n.s. 16: 29 (2006) 34 35 Raperostelium potamoides (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 36 37 Fungorum IF553735). Dictyostelium potamoides Cavender et al., Mycologia 97: 507 (2005) 38 39 Raperostelium reciprocatum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 40 41 (Index Fungorum IF553736). Dictyostelium reciprocatum Cavender et al., Mycologia 105: 42 622 (2012) 43 44 45 Raperostelium reciprocatum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin var. transitum 46 (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Fungorum IF553656). 47 48 Dictyostelium reciprocatum Cavender et al. var. transitum Cavender et al., Mycologia 105: 49 629 (2012) 50 51 52 Raperostelium tenue (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 53 Fungorum IF553737). Dictyostelium tenue Cavender et al., Amer. J. Bot. 66: 213 (1979) 54 55 56 57 58 59 60 61 62 63 64 65 1 2 3 4 5 Tieghemostelium S.Baldauf, S.Sheikh & Thulin, gen. nov. (Index Fungorum IF553751). Formatted: German (Germany) 6 7 Type: Tieghemostelium lacteum (Tiegh.) S.Baldauf, S.Sheikh & Thulin (Fig. 14) 8 Diagnosis: New genus, sister group of Hagiwaraea and Raperostelium together, from both of 9 10 which it differs by having in the SSU rRNA gene GCAA (not TCCG, TTCG, TTTG or 11 CTCG) in the nucleotide positions 246-249 and CGA (not AGG or GGG) in the positions 12 13 511-513 of Supplementary Material alignment S10 (Figs 2, 11D). 14 15 Description: Sorocarps with cellular stalks, sometimes with an acellular apical stretch, 16 colorless, delicate, 0.3-2.5 mm high, base simple or clavate, solitary or clustered, 17 18 branches absent or sparse and irregular. Spore shape variable 19 (ellipsoid/oblong/globose), likewise granule presence/absence and arrangement, 3.5- 20 21 11.0 ×1.8-4.8 µm. Microcysts known for most species, macrocysts known for T. 22 lacteum (D. Anderson and J. Cavender, unpublished). Non-streaming aggregation, 23 24 slug migration present or absent, acrasin pterin (T. lacteum) or unknown. 25 Etymology: Named after Philippe Édouard Léon van Tieghem (1839-1914), French botanist 26 27 and mycologist, to whom “we owe our first clear insight into the true and unique nature of the 28 29 so-called cellular slime molds” (Raper 1984), and who is the author of several species of 30 dictyostelids and other sorocarpic amoebae, including the type of Tieghemostelium. 31 32 33 Tieghemostelium angelicum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 34 35 (Index Fungorum IF553738). Dictyostelium angelicum Cavender et al., Mycologia 105: 624 36 (2012) 37 38 39 Tieghemostelium dumosum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 40 (Index Fungorum IF553739). Dictyostelium dumosum Cavender et al., Mycologia 105: 627 41 42 (2012) 43 44 Tieghemostelium lacteum (Tiegh.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 45 46 Fungorum IF553740). Dictyostelium lacteum Tiegh., Bull. Soc. Bot. France, Mém. 27: 320 47 (1880) 48 49 Tieghemostelium lacteum (Tiegh.) S.Baldauf, S.Sheikh & Thulin var. papilloideum 50 51 (Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Fungorum IF553741). 52 Dictyostelium lacteum papilloideum 53 Tiegh. var. Cavender, Amer. J. Bot. 63: 68 (1976) 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Tieghemostelium menorah (Vadell & Cavender) S.Baldauf, S.Sheikh & Thulin, comb. nov. 3 4 (Index Fungorum IF553742). Dictyostelium menorah Vadell & Cavender, Mycologia 99: 117 5 (2007) 6 7 Tieghemostelium montium 8 (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 9 Fungorum IF553743). Dictyostelium montium Cavender et al., Mycologia 105: 625 (2012) 10 11 Tieghemostelium simplex (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index 12 13 Fungorum IF553744). Dictyostelium simplex Cavender et al., Mycologia 105: 614 (2012) 14 15 Tieghemostelium unicornutum (Cavender et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. 16 17 (Index Fungorum IF553745). Dictyostelium unicornutum Cavender et al., Mycologia 105: 616 18 (2012) 19 20 21

22 23 Genus of Dictyosteliales not Assigned to Family 24 25 26 Coremiostelium S.Baldauf, S.Sheikh, Thulin & Spiegel, gen. nov. (Index Fungorum Formatted: German (Germany) 27 IF553752). Type: Coremiostelium polycephalum (Raper) S.Baldauf, S.Sheikh & Thulin (Fig. 28 29 15) 30 Diagnosis: New genus differing from Dictyostelium, Hagiwaraea, Polysphondylium, 31 32 Raperostelium, Speleostelium and Tieghemostelium by having the stalks of the sorocarps 33 34 forming a single column and diverging only terminally, and by having in the SSU rRNA gene 35 TAAA (not CAAG, CAAT, GAAG or CAAA) in the nucleotide positions 187-190 and 36 37 CCAG (not TTAA, TTAG, TTGA, GCGG, CTAT, TTAC, ATAA or ATAG) in the positions 38 1129-1132 of Supplementary Material alignment S11 (Figs 2, 11E). 39 40 Description: Sorocarps with cellular stalks, colorless, 0.35-0.65 mm in height, 41 typically coremiform and adherent along most of their length and diverging only 42 43 terminally. Microcysts common, macrocysts informally reported. Spores elliptic to 44 reniform in outline, 6.0-7.5 × 3.0-3.5 µm, granules often present but not consistently 45 46 polar. Streaming aggregation, slug migration stalkless, acrasin unknown. 47 48 Etymology: The name alludes to the typically coremiform fructifications with the stalks of 49 the sorocarps adherent along most of their length. 50 51 Note: According to the results of Singh et al. (2016), Coremiostelium would be a member of 52 Dictyosteliaceae. 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 3 4 Coremiostelium polycephalum (Raper) S.Baldauf, S.Sheikh, Thulin & Spiegel, comb. nov. 5 (Index Fungorum IF553746). Dictyostelium polycephalum Raper, J. Gen. Microbiol. 14: 717 6 7 (1956) 8 9 10 11 Genus not Assigned to Family or Order 12 13 Synstelium S.Baldauf, S.Sheikh & Thulin, gen. nov. (Index Fungorum IF553753). Type: 14 Synstelium polycarpum 15 (F.Traub et al.) S.Baldauf, S.Sheikh & Thulin (Fig. 16) 16 Diagnosis: New genus differing from all other dictyostelids by having in the SSU rRNA gene 17 18 TCTA (not TTCG, TTCA, TTCT, TTTA, TAAA, TGGT, ACTC, TCAC, etc) in the 19 nucleotide positions 270-273 and CAATTT (not CAGTAT, CAATAT, TAACAC, TAATAC, 20 21 etc) in the positions 607-612 of Supplementary Material alignment S12 (Figs 2, 11F). 22 Description: Sorocarps with cellular stalks, unbranched, clustered and adherent over 23 24 lower 1/3 of final height, colorless or with faint yellow stalk, typically 3-7 mm in 25 height. Spores 7.8 × 2.7 µm, reniform to elliptic in outline, with loosely arranged polar 26 27 granules. Microcysts and macrocysts unknown. Streaming aggregation, no slug 28 29 migration, acrasin unknown. 30 Etymology: The prefix “syn-” refers to the clustered sorocarps with the stalks adherent near 31 32 the base. 33 Note: According to the results of Singh et al. (2016), Synstelium would be a member of 34 35 Acytosteliaceae. 36 37 Synstelium polycarpum (F.Traub et al.) S.Baldauf, S.Sheikh & Thulin, comb. nov. (Index Formatted: German (Germany) 38 39 Fungorum IF553747). Dictyostelium polycarpum F.Traub et al., Amer. J. Bot. 68: 164 (1981) 40 41 42 43 Species incertae sedis 44 45 46 Dictyostelium arabicum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 17: 110 (1991) 47 48 Dictyostelium culliculosum Yu Li & Xiao L.He, Mycotaxon 106: 380 (2008) 49 50 Dictyostelium dichotomum Vadell & Cavender, Mycologia 99: 116 (2007) 51 52 Dictyostelium germanicum 53 Cavender et al., Bot. Helv. 105: 201 (1995) 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Dictyostelium globisporum Yu Li & Pu Liu, Mycologia 103: 641 (2011) 3 4 Dictyostelium irregulare L.S.Olive et al., Amer. J. Bot. 54: 354 (1967), as “irregularis” 5 6 7 Dictyostelium magnum H.Hagiw., Bull. Natl. Sci. Mus., Tokyo, B 9: 155 (1983) Formatted: German (Germany) 8 9 Dictyostelium microsorocarpum Yu Li & Xiao L.He, Mycotaxon 111: 287 (2010) 10 11 Dictyostelium roseum Tiegh., Bull. Soc. Bot. France 27: 320 (1880) Formatted: German (Germany) 12 13 14 Dictyostelium vermiforme Vadell & Cavender, Mycologia 99: 118 (2007), as “vermiformum” 15 16 17 18 Genus incertae sedis 19 20 21 Coenonia Tiegh., Bull. Soc. Bot. France 31: 304 (1884). Type: Coenonia denticulata Tiegh. 22 23 24 Coenonia denticulata 25 has never been recollected, but the crampon-shaped base described for 26 this species has been compared with the basal support found in species here treated as 27 28 members of Hagiwaraea. However, some other features, such as the cupule-like structure 29 with a finely dentate rim said to surround the spores in C. denticulata, have no parallel among 30 31 members of Hagiwaraea, or among other known dictyostelids (Raper 1984). Coenonia 32 therefore remains an enigma and may or may not be a dictyostelid. 33 34 35 36 37 Methods 38 39 40 41 The new classification is based on SSU rRNA gene phylogeny (Romeralo et al. 2011; Schaap 42 et al. 2006; Supplementary Material Fig. S1). The one exception is the root, which is not 43 44 resolved by SSU rRNA (Schaap et al 2006), but is strongly and consistently supported by 45 multi-protein phylogeny (Romeralo et al. 2014; Sheikh et al. 2015; Singh et al. 2016). Taxon 46 47 naming is made according to the International Code of Nomenclature for algae, fungi, and 48 49 plants (ICN) (McNeill et al. 2012), and the use of molecular characters as taxon diagnostics 50 follows the guidelines proposed by Tripp and Lendemer (2014). 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Molecular characters for group diagnoses utilized SSU rRNA with sequences 3 4 aligned for all taxa and for specific groups using MUSCLE (Edgar 2004) with default settings 5 as implemented in AliView (V1.19-beta-3, Larsson 2014). These alignments were further 6 7 refined by eye to correct for obvious errors that are inevitable in automated SSU rRNA 8 alignment (e.g. Cole et al. 2014). The full alignment and group-specific alignments are 9 10 provided as supplementary data (Supplementary Material Figs S2-S13, respectively). Two 11 molecular synapomorphies were chosen for each new taxon diagnosis, and the full set of 12 13 synapomorphies for each group is shown in Supplementary Material Table S1. Diagnostic 14 15 morphological characters were added where available and for all genera, families and orders 16 brief morphological descriptions are given using the full range of original species 17 18 descriptions. 19 20 Phylogenetic reconstruction of the SSU rRNA tree (Supplementary Material 21 22 Fig. S13) utilized the full SSU rRNA alignment manually trimmed to remove poorly aligned 23 regions, yielding 1560 universally aligned positions (indicated on Supplementary Material 24 25 Fig. S13). Phylogenetic analyses were conducted using RAxML (V7.2.8, Stamatakis 2006) 26 with the GTR substitution model and a gamma correction for rate variation among sites 27 28 (GTRGAMMA). Clade support was determined using the same method and model for 1000 29 bootstrap replicates. Analyses including all sequences strongly support the extremely 30 31 divergent Cavenderia multistipes and C. nanopodium sequences as members of the genus 32 Cavenderia. These sequences were then deleted from the final analysis as such 33 34 disproportionately long branches tend to interfere with accurate tree reconstruction due to the 35 36 problem of long branch attraction (Bergsten 2005). 37 38 39 40 Acknowledgements 41 42 43 44 We thank Alastair Simpson and Pauline Schaap for helpful comments on the manuscript. We 45 46 also thank the Discover Life webserver (www.discoverlife.org/) for easy access to many 47 original species descriptions and the Cyberinfrastructure for Phylogenetic Research (CIPRES) 48 49 for the use of computational resources. 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 References Formatted: German (Germany) 3 4 Formatted: German (Germany) 5 6 Baldauf SL, Strassmann JE (2017) Dictyostelia. In Simpson AGB, Archibald JM, 7 8 Slamovits C (eds) Handbook of the Protists. Springer, in press 9 10 Bergsten J (2005) A review of long branch attraction. Cladistics 21:163-193 11 12 Brefeld JO (1869) Dictyostelium mucoroides. Ein neuer Organismus aus der Verwandschaft 13 14 der Myxomyceten. Abh Senckenberg Naturf Ges 7:85-107 15 16 Brefeld JO (1884) Polysphondylium violaceum und Dictyostelium mucoroides nebst 17 18 Bemerküngen zur Systematik der Schleimpilze. Untersuch Gesammt Mykol 6:1-34 19 20 Cavender JC, Vadell EM (2000) The genus Acytostelium. Mycologia 92:992-1008 21 22 Cavender JC, Stephenson SL, Landolt JC, Vadell EM (2002) Dictyostelid cellular slime 23 24 moulds in the forests of New Zealand. New Zeal J Bot 40:235-264 25 26 Cavender JC, Landolt JC, Romeralo M, Perrigo A, Vadell EM, Stephenson SL (2016) 27 28 New species of Polysphondylium from Madagascar. Mycologia 108:80-109 29 30 Cole JR, Wang Q, Fish JA, Chai B, McGarrell DM, Sun Y, Brown CT, Porras-Alfaro A, 31 Kuske CR, Tiedje JM (2014) Ribosomal Database Project: data and tools for high 32 33 throughput rRNA analysis. Nucleic Acids Res 42:D633-D642 34 35 Edgar R C (2004) MUSCLE: multiple sequence alignment with high accuracy and high 36 37 throughput. Nucleic Acids Res 32:1792-1797 38 39 Heidel AJ, Glöckner G (2008) Mitochondrial genome evolution in the social amoebae. Mol 40 41 Biol Evol 25:1440-1450 42 43 Larsson A (2014) AliView: A fast and lightweight alignment viewer and editor for large data 44 45 sets. Bioinformatics 30:3276–3278 46 47 Marchal E (1885) Champignons coprophiles de Belgique. Bull Soc Roy Bot Belgique 24:57- 48 74 49 50 51 McNeill J, Barrie FR, Buck WR, Demoulin V, Greuter W, Hawksworth DL, Herendeen 52 PL, Knapp S, Marhold K, Prado J, PrudʼHomme van Reine WF, Smith GF, Wiersema 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 JH, Turland NJ (eds) (2012) International Code of Nomenclature for algae, fungi, and plants 3 4 (Melbourne Code): Adopted by the Eighteenth International Botanical Congress Melbourne, 5 Australia, July 2011. Regnum Vegetabile 154. Koeltz Scientific Books, Königstein 6 7 8 Mehdiabadi NJ, Kronforst MR, Queller DC, Strassmann JE (2009) Phylogeny, 9 reproductive isolation and kin recognition in the social amoeba Dictyostelium purpureum. 10 11 Evolution 63:542-548 12 13 Oudemans CAJA (1885) Aanwinsten voor de flora mycologica van Nederland, IX en X. Ned 14 Kruidk Arch ser 2 4:203–278 15 16 17 Raper KB (1956) Factors affecting growth and differentiation in simple slime molds. 18 Mycologia 48:169–205 19 20 21 Raper KB (1984) The Dictyostelids. Princeton University Press, Princeton, 453 p 22 23 Romeralo M, Escalante R, Sastre L, Lado C (2007) Molecular systematics of dictyostelids: 24 25 58S ribosomal DNA and internal transcribed spacer region analyses. Eukaryotic Cell 6:110– 26 116 27 28 Romeralo M, Cavender JC, Landolt JC, Stephenson SL, Baldauf SL (2011) An expanded 29 30 phylogeny of social amoebas (Dictyostelia) shows increasing diversity and new 31 morphological patterns. BMC Evol Biol 11:84 32 33 34 Romeralo M, Skiba A, Gonzalez-Voyer A, Schilde C, Lawal H, Kedziora S, Cavender 35 JC, Glöckner G, Urushihara H, Schaap P (2013) Analysis of phenotypic evolution in 36 37 Dictyostelia highlights developmental plasticity as a likely consequence of colonial 38 multicellularity. Proc R Soc B Biol Sci 280:20130976 39 40 41 Schaap P, Winckler T, Nelson M, Álvares-Curto E, Elgie B, Hagiwara H, Cavender JC, 42 Milano-Curto A, Rozen DE, Dingermann T, Mutzel R, Baldauf SL (2006) Molecular 43 44 phylogeny and evolution of morphology in the social amoebas. Science 314:661–663 45 46 Sheikh S, Gloeckner G, Kuwayama H, Schaap P, Urushihara H, Baldauf SL. (2015) 47 48 Root of Dictyostelia based on 213 universal proteins. Mol Phylogenet Evol 92:53-62 49 50 Singh R, Schilde C, Schaap P (2016) A core phylogeny of Dictyostelia inferred from 51 52 genomes representative of the eight major and minor taxonomic divisions of the group. BMC 53 Evol Biol 16:251 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Stamatakis A (2006) RAxML-VI-HPC: maximum likelihood-based phylogenetic analyses 3 4 with thousands of taxa and mixed models. Bioinformatics 22:2688-2690 5 6 Swanson AR, Spiegel FW, Cavender JC (2002) Taxonomy, slime molds, and the questions 7 8 we ask. Mycologia 94:968–979 9 10 van Tieghem PEL (1880) Sur quelques Myxomycètes à plasmode agrégé. Bull Soc Bot 11 France Mém 27:317–322 12 13 14 van Tieghem PEL (1884) Coenonia, genre noveau de Myxomycètes à plasmode agrégé. Bull 15 Soc Bot France 31:303–306 16 17 18 Tripp EA, Lendemer JC (2014) Sleepless nights: When you canʼt find anything to use but 19 molecules to describe new taxa. Taxon 63:969–971 20 21

22 23 24 25 26 27 Figure Legends 28 29 30 31 Figure 1. Schematic overview of dictyostelid phylogeny and new taxonomy. The figure 32 33 shows all dictyostelid major groups that receive consistent and strong statistical support from 34 SSU rRNA phylogeny (Romeralo et al. 2011; Schaap et al. 2006; Supplementary Material 35 36 Fig. S1). The root, which is not well resolved by SSU rRNA (Schaap et al. 2006), is based on 37 three separate multi-protein phylogenies (Romeralo et al. 2014; Sheikh et al. 2015; Singh et 38 39 al. 2016). New names proposed herein are indicated in red. 40 41 Figure 2. Schematic diagram of the dictyostelid SSU rRNA alignment indicating regions 42 43 carrying taxonomic signatures. Dictyostelid-wide conserved blocks are indicated in grey and 44 labeled with upper case letters, while variable regions are indicated in red with lower case 45 46 letters. Regions containing molecular signatures are indicated with arrows pointing to the list 47 of taxa with signatures in the respective region. The positions refer to the global alignment 48 49 shown in Figure S13. The numbers represent start and end positions of the conserved regions 50 51 used for global dictyostelid phylogeny (Supplementary Material Fig. S1). 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Figure 3. SSU rRNA molecular signatures for dictyostelid taxa. Sequence signatures were 3 4 extracted from alignments of strict consensus sequences for the relevant taxa (Supplementary 5 Material files S2-S6). Alignment segments carrying signatures, which are highlighted with 6 7 dark background color, are shown for A. Acytosteliales, B. Rostrostelium, C. Heterostelium, 8 D. Cavenderia and Cavenderiaceae, and E. Raperosteliaceae. Coordinates are given above 9 10 each segment indicating the position of the segment within its group-specific alignment 11 (Supplementary Material file indicated at the top). The segment’s corresponding region in the 12 13 global alignment is given at the bottom of each segment and refers to the region designated in 14 15 Figure 2 and Supplementary Material alignment S13. 16 17 Figure 4. Acytostelium leptosomum, type of Acytostelium (type strain FG-12). A. 18 Aggregation. B. Cluster of sorogens. C. Late sorogen. D. Base. E. Tip. F. Myxamoebae. G. 19 20 Spores. H. Sorocarps. Scale bars: A =1 mm; B, C = 100 μm; D-G = 6 μm; H = 0.5 mm. 21 22 Reproduced from Cavender and Vadell (2000) with permission from Taylor & Francis Ltd 23 (www.tandfonline.com). 24 25 Figure 5. Rostrostelium ellipticum, type of Rostrostelium (type strain AE-2). A. Aggregation. 26 27 B. Cluster of early and late sorogens. C, D. Narrowed late sorogens. E. Myxoamoebae. F. 28 Spores. G. Sorocarps. Scale bars: A = 100 μm; B-D = 100 μm; E, F = 6 μm; G = 150 μm. 29 30 Reproduced from Cavender and Vadell (2000) with permission from Taylor & Francis Ltd 31 32 (www.tandfonline.com). 33 34 Figure 6. Heterostelium pallidum, type of Heterostelium (strain NZ77A). A. Aggregation. B. 35 Late pseudoplasmodia. C. Base. D. Early and late sorogens. E. Tips. F. Elliptical spores with 36 37 unconsolidated polar granules. G. Myxamoebae. H. Solitary and tightly clustered sorocarps. I. 38 39 Whorl. Scale bars: A, B, D = 0.4 mm; C = 20 μm; E, I = 10 μm; F, G = 8 μm; H = 1mm. 40 Reproduced from Cavender et al. (2002) with permission from Taylor & Francis Ltd 41 42 (www.tandfonline.com). 43 44 Figure 7. Cavenderia fasciculata, type of Cavenderia (strain NZ155B). A. Two patterns of 45 46 aggregation: large streams, finely fragmented, and a small crateriform late aggregation. B, C. 47 Solitary (left) and clustered (right), early (B) and late (C) sorogens. D. Clavate base. E. 48 49 Capitate tips. F. Elliptical spores with consolidated polar granules. G. Myxamoebae. H. 50 Solitary unbranched sorocarp. I. Clustered branched sorocarp with small young sorogens 51 52 surrounding bases. Scale bars: A-C =0.5 μm; D = 20 μm; E = 10 μm; F = 5 μm; G = 15 μm; 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 H, I = 0.5 mm. Reproduced from Cavender et al. (2002) with permission from Taylor & 3 4 Francis Ltd (www.tandfonline.com). 5 6 Figure 8. Dictyostelium mucoroides, type of Dictyostelium. A. Aggregation. B. Spores. C-D. 7 8 Tip formation and spores. E-G. Sorocarps. Scale bars: A = 0.5 mm; B, C, D = 10 μm; E, F, G 9 = 1 mm (Photos by A. Swanson and F. Spiegel). 10 11 Figure 9. Polysphondylium violaceum, type of Polysphondylium (strain NZ16B). A. Large 12 13 aggregation. B. Early and late sorogens in a cluster. C. Clustered and solitary sorocarps as 14 seen reacting to light. D. Base. E. Tip. F. Elliptical spores with consolidated polar granules. 15 16 G. Myxamoebae. Scale bars: A, B = 1 mm; C = 2 mm; D, E = 25 μm; F = 5 μm; G = 15 μm. 17 18 Reproduced from Cavender et al. (2002) with permission from Taylor & Francis Ltd 19 (www.tandfonline.com). 20 21 Figure 10. Speleostelium caveatum, type of Speleostelium (type strain B4-3). A. Clustered 22 23 sorocarps. B. Spores containing prominent granules. C. Vegetative myxamoebae. D. Young 24 25 aggregations formed without inflowing streams. E. Sorocarps of the smaller type (larger type 26 not illustrated). F. Sorophores. For magnification, see Raper (1984). Reproduced from Raper 27 28 (1984) with permission from Princeton University Press. 29 30 Figure 11. SSU rDNA molecular signatures for dictyostelid taxa. Sequence signatures 31 32 were extracted from alignments of strict consensus sequences for the relevant taxa 33 (Supplementary Material files S7-S12). Alignment segments carrying signatures, which are 34 35 highlighted with dark background color, are shown for A. Speleostelium, B. Hagiwaraea, C. 36 Raperostelium, D. Tieghemostelium, E. Coremiostelium and F. Synstelium. Coordinates are 37 38 given above each segment indicating the position of the segment within its group-specific 39 alignment (Supplementary Material file indicated at the top). The segment’s corresponding 40 41 region in the global alignment is given at the bottom of each segment and refers to the region 42 designated in Figure 2 and Supplementary Material S13. The blocked lines show the start and 43 44 end of the denoted alignment region, and the arrows show continuation of the region. 45 46 Figure 12. Hagiwaraea rhizopodium, type of Hagiwaraea (type strain Pan-33). A. Sorocarps. 47 48 B. Spores containing obvious polar granules. C. Vegetative myxamoebae. D. Two 49 characteristic aggregations. E. Larger aggregation; note that inflowing streams have broken 50 51 up in subcentral area. Fruiting by such dissociated myxamoebae must await emergence of 52 53 new centers. F. Apical area of developing sorocarp showing terminally expanded sporophore 54 55 56 57 58 59 60 61 62 63 64 65 1 2 sheath and characteristic orientation of myxamoebae that surround it. G. Crampon base and 3 4 sporophore showing similar differentiation of constituent cells. H. Clustered sorogens arising 5 from a single aggregation. I. Mature sorocarps of the same strain and young sorogens along 6 7 colony edge (below). For magnification, see Raper (1984). Reproduced from Raper (1984) 8 with permission from Princeton University Press. 9 10 11 Figure 13. Raperostelium minutum, type of Raperostelium. A. Aggregation. B. Spores. C, E. 12 Sorocarps. D. Tip formation. Scale bars: A = 0.5 mm; B = 10 μm; C = 1 mm; D = 10 μm; E = 13 14 5mm (Photos by A. Swanson and F. Spiegel).. 15 16 Figure 14. Tieghemostelium lacteum, type of Tieghemostelium (strain UI-14). A. Sorocarps. 17 18 B. Vegetative myxamoebae. C. Small, mound-like aggregations formed without stream. 19 Insert, aggregation via streams. D. Multiple sorogens arising from a single small aggregation. 20 21 E. Three aggregation areas from which multiple, thin sorogens are developing. F. A single 22 sorogen in process of fruiting. G. Typical sporophore composed of a single tier of vacuolated 23 24 cells. H. Base of clustered sorocarps showing cellular structure. I. Bases of sorocarps 25 photographed to show expanded aprons of slime that anchor structures of substrate. J. 26 27 Globose spores characteristic of this species. For magnification, see Raper (1984). 28 Reproduced from Raper (1984) with permission from Princeton University Press. 29 30 31 Figure 15. Coremiostelium polycephalum, type of Coremiostelium (type strain S-4). A. 32 Coremiform sorocarps and newly formed pseudoplasmodia. B. Sorocarps. C. Spores, showing 33 34 characteristic shape and commonly a single polar granule. D. Myxamoebae beneath 35 coverglass; note empty spore case (arrow) and how it was broken to release the protoplast. E. 36 37 A developing cell aggregation showing typical radial pattern. F. Aggregation at edge of a 38 39 bacterial streak; note ridges that reflect waves of converging myxamoebae. G. Aggregations 40 in process of formation (left) and delicate migrating pseudoplasmodia emerging from two 41 42 centers of aggregation (right). H. Two typical migrating pseudoplasmodia. I. Migrating 43 pseudoplasmodium. For magnification, see Raper (1984). Reproduced from Raper (1984) 44 45 with permission from Princeton University Press. 46 47 Figure 16. Synstelium polycarpum, type of Synstelium (type strain GR-4). A. Spores showing 48 49 narrow elliptical form and unconsolidated polar granules. B. Vegetative myxamoebae. C. 50 Aggregations. D. Late aggregates with many papillae. E. Sorogens beginning to form. F. 51 52 Field of clustered sorocarps; note diverging sorogens at lower right. For magnification, see 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Raper (1984). Reproduced from Raper (1984) with permissions from Princeton University 3 4 Press. 5 6 7 8 Appendix A. Supplementary Data 9 10 11 Table S1. Molecular synapomorphies (signatures) using SSU rRNA for each group using 12 sequences in Supplementary Material Figures S2-S12. 13 14 Figure S1. Global phylogeny of dictyostelids using universally aligned regions of SSU 15 16 rDNA. The tree shown was derived by maximum likelihood analysis of 1560 universally 17 18 aligned SSU rDNA positions (Fig. 2; Supplementary Material file S13). Analyses were 19 conducted using RAxML (version 7.2.8) with the GTR substitution model and a gamma 20 21 correction for rate variation among sites (GTRGAMMA), with 1000 bootstrap replicates. 22 Taxa are shown with their revised names followed by strain and GenBank accession number 23 24 for their SSU sequences. Colours are used to indicate the different genera. Bootstrap support 25 values above 50% shown on the relevant branches. 26 27 28 Figure S2. Group-specific SSU rDNA sequence alignment for Acytosteliales. Sequences 29 were aligned using MUSCLE (Edgar 2004) with default settings using the program AliView 30 31 (version 1.9-beta-3) (Larsson 2004) followed by manual correction of obvious errors. 32 33 Figure S3. Group-specific SSU rDNA sequence alignment for Rostrostelium. Sequences were 34 35 aligned as described in Supplementary Material Figure S2. 36 37 Figure S4. Group-specific SSU rDNA sequence alignment for Heterostelium. Sequences 38 were aligned as described in Supplementary Material Figure S2. 39 40 41 Figure S5. Group-specific SSU rDNA sequence alignment for Cavenderiaceae and 42 Cavenderia. Sequences were aligned as described in Supplementary Material S2. 43 44 45 Figure S6. Group-specific SSU rDNA sequence alignment for Raperosteliaceae. Sequences 46 were aligned as described in Supplementary Material Figure S2. 47 48 Speleostelium 49 Figure S7. Group-specific SSU rDNA sequence alignment for . Sequences were 50 aligned as described in Supplementary Material Figure S2. 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 Figure S8. Group-specific SSU rDNA sequence alignment for Hagiwaraea. Sequences were 3 4 aligned as described in Supplementary Material Figure S2. 5 6 Figure S9. Group-specific SSU rDNA sequence alignment for Raperostelium. Sequences 7 8 were aligned as described in Supplementary Material Figure S2. 9 10 Figure S10. Group-specific SSU rDNA sequence alignment for Tieghemostelium. Sequences 11 were aligned as described in Supplementary Material Figure S2. 12 13 14 Figure S11. Group-specific SSU rDNA sequence alignment for Coremiostelium. Sequences 15 were aligned as described in Supplementary Material Figure S2. 16 17 Synstelium 18 Figure S12. Group-specific SSU rDNA sequence alignment for . Sequences were 19 aligned as described in Supplementary Material Figure S2. 20 21 Figure S13. Master alignment of all dictyostelid SSU rDNA sequences. Sequences were 22 23 aligned using MUSCLE (Edgar 2004) with default settings using the program AliView 24 25 (version 1.19-beta-3) (Larsson 2014) followed by manual correction of obvious errors. The 26 top row in the alignment files indicates conserved regions used for phylogeny with capital 27 28 letter designations and highly variable regions that were excluded with lower case letters. 29 Variable regions consisting of less than six alignment columns are not shown. 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Figure1

"Gr 4" Dictyostelium

Dictyosteliaceae

"violaceum" Polysphondylium

Dictyosteliales "polycephalum" Coremiostelium "Gr 3C" Raperostelium

"Gr 3B" Hagiwaraea

Raperosteliaceae "Gr 3A" Tieghemostelium "polycarpum" Synstelium Speleostelium

"Gr 2B" Heterostelium

Acytosteliaceae Rostrostelium

Acytosteliales "Gr 2A" Acytostelium

Cavenderiaceae "Gr 1" Cavenderia Figure2 Acytosteliales Rostrostelium Heterostelium Cavenderiaceae Cavenderia Tieghemostelium Synstelium Hagiwaraea Raperostelium

Master Region Region Region Region A b d f Region h Region I j Region K l n Region O alignment C E G M Positions 0 184 205 234 302 659 1540 1786 1984 198 215 242 311 906 1644 1799 Rostrostelium Speleostelium Tieghemostelium Acytosteliales Speleostelium Coremeostelim Synstelium Cavenderiaceae Cavenderia Raperosteliaceae Hagiwaraea Raperostelium Coremiostelium Figure3

A. Acytosteliales (Supplemental material S2) 550 560 Cavenderia Acytostelium Rostrostelium Heterostelium Speleostelium Tieghemostelium Hagiwaraea Raperostelium Polysphondylium Dictyostelium Coremiostelium Synstelium Region I Region K

B. Rostrostelium (Supplemental material S3)

140 150 Rostrostelium Heterostelium Acytostelium Region A Region I

C. Heterostelium (Supplemental material S4) 370 380 Heterostelium Rostrostelium Acytostelium Region I Region I

D. Cavenderiaceae, Cavenderia (Supplemental material S5) 480 490 Cavenderia Acytostelium Rostrostelium Heterostelium Region I Region K

E. Raperosteliaceae (Supplemental material S6)

1060 1070 Raperostelium Hagiwaraea Speleostelium Tieghemostelium Dictyostelium Coremiostelium Polysphondylium Region K Region K Figure4 1002 MYCOLOGIA

with some undifferentiated, scattered cells within (FIG. O1D). Microcysts present. Etymology. Referring to the slender sorophores. Habitat and distribution. Widely distributed in sur- A face soil and leaf mold of temperate deciduous forest as well as tropical forest types. Cultures examined. USA. ILLINOIS: Funk's Grove, Uni- versity of Illinois Research Area, from deciduous forest, 27~ 1952, K. B. Raper (HOLOTYPE FG 12 A); FG 13; GUA- TEMALA. Tikal, E.M. Vadell, E8 (OH583). B ( Notes. Distinguishing characteristics include soli- tary to clustered sorocarps of 25 or more per cluster but usually less, radiate aggregations, spores not ger- minating immediately and presence of microcysts.

C Acytostelium ellipticum Cavender J. Gen. Microbiol. 62: 119-123, Figs. 31-40 (1970) FIGS. 11A-C, 12 0 Sorocarps solitary, gregarious and clustered, erect to prone, unbranched, extremely delicate and rang- ing from less than 200 to 1000 Jim in height (mostly 250-500 Jim), when cultivated at 24-27 C with E. coli strain 281 (FIGS. 11C, 12G). Sorophores acellular, 1- 0 OOo0G Q 0 2 jLm diam at 100 jLm from the inconspicuous bases (2 Jim). The tip is piliform. Sorogens narrow, elon- gated, with wide bases (ventricose-rostrate) (FIGS. H 11B, 12B), later contracting and becoming filiform FIG. 10. Acytostelium leptosomum, FG-12. A. Aggregation. (70-150 Jim). Sorogens may be tightly clustered giv- B. Cluster of sorogens. C. Late sorogen. D. Base. E. Tip. F. ing rise to a sequence of smaller sorocarps. Sori glo- Myxamoeba. G. Spores. H. Sorocarps. Bars: A = 1 mm; B, bose, hyaline (20-50 Jim, mostly 25-30 jim). Spores C = 100 ljm; D-G = 6 Jim; H = 0.5 mm. elliptical (4-6 X 2-3 jLm, mean 5.4 X 2.5 jLm) mostly with a cluster of prominent polar granules (FIGS. 11 A, 12F), but also showing sparse large granules not consistently polar when spores are misshapen. Aggre- in J. Gen. Microbiol. 18: 16-32, Figs. 1-20 gation mound-like 100-300 jim (FIG. 12A), some- (1958). FIGS. 6J-L, 10 times radiate with short but marked streams. Aggre- Sorocarp solitary, gregarious and clustered, un- gations may remain several days without further de- branched, 500-1500 jLm in height, erect to prone velopment and sometimes appear congealed on the and sinuous, when cultured at 24-27 C on E. coli agar surface. stain 281 (FIG. O1H). Sorophores acellular, colorless, Etymology. Referring to the elliptical shape of the unbranched, sorocarps are 2-3 Jim diam at 100 jLm spores. from the base. The tip is piliform. Sorogens fusiform Habitat and distribution. Leaf mold and surface (FIGS. 6K, 10C) (100 jim, rarely up to 200 jLm). So- soil of tropical forest, Trinidad, West Indies, Guyana, rogens number up to 25 or more per cluster. Sori Colombia and Peru, South America globose (30-50 jim diam), whitish to hyaline, well Cultures examined. TRINIDAD. Arena Forest Reserve, separated from each other and becoming tangled from tropical evergreen forest soils, 1968, J.C. Cavender [HOLOTYPE AE-2 (OH78)]; MJ-1 (OH79). with age. Spores generally globose (FIG. 6J), from 5 Notes. Distinguishing characteristics include small, to 7 jim (mean 5.86 Jim), with some peripheral gran- delicate sorocarps, elongated ventricose-rostrate so- ules. Germination of spores does not occur immedi- rogens, aggregations with short streams and elliptical ately after the collapse of the sorus on the substra- spores with polar granules. tum. Aggregations radiate (FIGS. 6K, 10A) (1-1.5 jLm or larger) with wide lateral streams becoming nar- rower with age (FIGS. 6K, 10A), irregular and some- Acytostelium minutissimum Cavender et Vadell sp. times anastomosed. Aggregations may not render nov. FIGS. 11D-F, 13 fruiting bodies. Bases covered with abundant sheath, Sorocarpia pusilla, solitaria et ephimera, sine ramis, 70-

This content downloaded from 130.238.82.48 on Thu, 13 Oct 2016 15:12:08 UTC All use subject to http://about.jstor.org/terms Figure5 1004 MYCOLOGIA

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H C I 0 t q S I ¢ E I 0 0 Cft ^F FIG. 12. Acytostelium ellipticum Cavender, AE-2. A. Ag- ' :0'O%A (Q ( E gregation. B. Cluster of early and late sorogens. C, D. Nar- . rowed late sorogens. E. Myxoamoeba. F. spores. G. Soro- l': carps. Bars: A = 100 ,xm; B-D = 100 ILm; E, F = 6 Jim; G = 150 ILm. FIG. 13. Acytostelium minutissimum, VC-8. A, B. Aggre- gation. C. Sequence of sorogen development (1-6). D. Base and sorophore. E. Spores. F. Collapsed sorocarps. G. My- xamoebae. H, I. Sorocarps. Bars: A-D = 50 jim; E, G = 6 (FIGS. 11F, 13H, I), 70-130 |jm (mean 100 txm), oc- jLm; F, H, I = 50 ,Jm. casionally 150 Ijm, rarely less than 70 Ijm, and ex- ceptionally up to 200 jLm in height, regularly spaced (100-200 jLm), ephemeral. Sorocarps tend to bend over near the tip (FIG. 13H), when cultivated at 24- (FIGS. 11F, 13C) (20-50 jLm). Unaggregated myx- 27 C with E. coli strain on NNA. Sorophores tapered amoebae form cysts. from the clavate bases (1.5-3 jLm) to the elongated Etymology. Referring to the minute size of the so- and piliform tip (FIGS. 11F, 13D) (0.1 jLm or less), rocarps. often without holding a sorus (FIG. 13F). At 40-50 Habitat and distribution. Found only from volcanic jLm from the base (1.5-3jLm diam) the sorophore soil and leaf mold of elfin woodland, Costa Rica. constricts sharply to 1 jLm (FIGS. 11F, 13D). Sorogens Cultures examined. COSTA RICA. GUANACASTE: from are very thin, apically narrowed, vermiform (FIG. elfin woodland soil at the summit (1670 m) of Volcan Ca- 13C) and arise from a center (20-30 Jim). Single cao, 10° 56' 5" N, 85° 27' 17' W, 1998, J.C. Landolt and S.L. Stephenson [HOLOTYPE VC8 (OH804) ]. sorogens are rostrate at first, mostly prone (20 to 50 Notes. Distinguishing characteristics include soro- jim) (FIG. 13C). Spores are widely elliptical, some carps solitary, minute and ephemeral, sorophore con- oblong to globose (FIGS. 11D, 13E), often not well stricted at 40-50 JLm from the base, spores widely defined, 6-7 X 3-4 jLm (mean 6.4 X 3.8 Jim) and elliptical and irregular with granules and vesicles 5-7 Jim when spherical, with vesicles and granules within, pseudoplasmodia ventricose rostrate, minute within. Sori globose to subglobose, pale to hyaline, mound-like aggregations or with a reticulate pattern from 15 to 30 jLm, rarely up to 35 !jm diam. Aggre- of flattened streams. gations very small (20-70 ,jm) with short, sharp streams (FIGS. lIE, 13B) or extended (100-200 jLm) with anastomosed, undefined, flattened streams Acytostelium aggregatum Cavender et Vadell sp. (FIGS. 11E, 13A) or mound-like and irregular in nov. FIGS. 11G-I, 14 shape. Pseudoplasmodia may adopt a rostrate shape Sorocarpia solitaria aut racemosa, sinuosa, prona, 70-350

This content downloaded from 130.238.82.48 on Thu, 13 Oct 2016 15:12:08 UTC All use subject to http://about.jstor.org/terms Cavender et al.—Dictyostelid slime moulds from NZ 243 Figure6 Fig. 3 Features of Polysphon- dylium pallidum (NZ77A). A, Ag- gregation; B, Late pseudo- plasmodia; C, Base; D, Early and late sorogens; E, Tips; F, Ellipti- cal spores with unconsolidated polar granules; G, Myxamoebae; H, Solitary and tightly clustered sorocarps; I, Whorl. Scale bars: A, B, D = 0.4 mm; C = 20 um; E, I = 10 urn; F, G = 8 um; H = 1 mm.

polar granules, sometimes united (Fig. 1G, 3F). Olive 2 (FH), from dung of an ass, Liberia, Africa, Aggregation is of the "violaceum" type (Fig. 1H, collected by E. W. Olive on or before 1897 3A,B). The streams are wide and asymmetrically (Hagiwara 1989). Numerous isolations have been distributed, and culture conditions require charcoal made from different forests of the world, including for good fruiting. Sorocarps develop well between those of cold climates (Raper 1984). 22-24°C. Polysphondylium violaceum Brefeld, 1884, in ETYMOLOGY: pallidum, referring to the lack of color. Raper, 1984, pp. 371-374, fig. 13-1 A-D CULTURE EXAMINED: Strain NZ77. Strain NZ16B; Fig. 1D-F, 4A-G. HABITAT AND DISTRIBUTION: Polysphondylium Sorocarps solitary to loosely clustered, 2-5 mm in pallidum is a cosmopolitan species first reported height, erect to semierect, with 3 to 8 whorls of vio- from New Zealand by Olive (1975), but without laceous pigmented small lateral sori, nodes regularly specific locality data. In our study it was recovered spaced (Fig. AC). Sorophores with vinaceous pig- from only two sites, one in Taupo and the other in ment, elongated (4-15 mm) in one-sided illumina- Northland. tion and may not develop whorls. The number of NOTES: A lectotype oí Polysphondylium pallidum, whorls varies from 3 to 8 when cultivated on existing only as a preserved slide, was designated as nonnutrient agar at 22-25°C; under diffuse light, Cavender et al.—Dictyostelid slime moulds from NZ 251 Figure7 Fig. 9 Features of Dictyostelium fasciculatum (NZ155B). A, Two patterns of aggregation: Large streams, finely fragmented, and a small crateriform late aggregation; B, C, Solitary (left) and clustered (right), early (B) and late (C) soro- gens; D, Clávate base; E, Capitate tips; F, Elliptical spores with consolidated polar granules; G, Myxamoebae; H, Solitary unbranched sorocarp; I, Clustered branched sorocarp with small young sorogens surrrounding bases. Scale bars: A-C = 0.5 mm; D = 25 urn; E = 10 um; F = 5 um; G =15 um; H, I = 0.5 mm.

NOTES: This species is distinguished by its elliptical alongside sorophore bases (Fig. 9I). Branches gen- spores with polar to subpolar granules and the dif- erally produce a clávate base. ferent types of aggregation, which are all variations on the "violaceum" type. The fruiting body can also Dictyostelium giganteum Singh, 1947, in Raper, resemble D. mucoroides. The strain from New Zea- 1984, pp. 263-267, fig. 12-3 A-E land has slightly wider spores than D. mucoroides Strain NZ20A; Fig. 10J-L, 11A-I. and conspicuous granules with variable distribution Sorocorps are solitary, very large, unbranched, erect within the spores. Bases are prominent, with en- or prone to prostrate, and ranging mostly from 5 to larged supportive cells and a conspicuous sheath >50 mm, being very phototropic (Fig. 11C, H,I). which terminates in a digitate pattern. In older cul- Sorophores thick and stout, erect or prone and tures, one to several small sorogens commonly form gigantic, slightly tapered from round bases (Fig. Figure8

A B C

D E F

G 244 New Zealand Journal of Botany, 2002, Vol. 40 Figure9 Fig. 4 Features of Polysphon- dylium violaceum (NZ16B). A, Large aggregation; B, Early and late sorogens in a cluster; C, Clus- tered and solitary sorocarps as seen as reacting to light; D, Base; E, Tip; F, Elliptical spores with consolidated polar granules; G, Myxamoebae. Scale bars: A, B = 1 mm; C = 2 mm; D, E = 25 um; F = 5 um; G = 15 um.

G

each whorl with 1 to 5 recurved branches (mostly Sorogens rise up from the centre of a small aggre- 2-3) of different sizes, generally of 80 to 170 (Am. gation and adopt a tear-like shape until reaching Solitary branches are larger, reaching 200 to 700 (Am 200 (Am (Fig. 4B). Myxamoebae irregular with vis- with conspicuous bases. Terminal sori violaceous, ible vacuoles of different sizes (Fig. 3G). 100-200 um diam. and spaced 250-350 um from the ETYMOLOGY: violaceum, referring to the violaceous closest whorl. Lateral sori are more regular, not pigmentation. exceeding 70 (Am, a n d mostly from 40 to 60 (Am ( F i g . 1F, AC). Spores are elliptical to oblong, vinaceous CULTURE EXAMINED: NZ16B. to hyaline, with consolidated granules, mostly 5.5- HABITAT AND DISTRIBUTION: Polysphondylium viola- 7 x ?>-\ (Am (Fig. 1D, 4F). Aggregations are of the ceum is a common and widespread inhabitant of "violaceum" type, radiate and reaching 2 mm or forest soils and litter, but it is not present in extreme more in diameter (Fig. 1E, 4A). This type of aggre- cold environments. The species was first reported gation breaks up to produce more than one sorogen. from New Zealand by Olive (1975), but without --- ~ - s-~ ., '' is Figure10 ,~ =i, P F a k~r ^.~~; ~ ' ~ F ~ ~~ ~'' ~i -'

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A. Speleostelium (Supplemental material S7) 200 210 Speleostelium Tieghemostelium Hagiwaraea Raperostelium Region d Region M

B. Hagiwaraea (Supplemental material S8)

860 870 Hagiwaraea Raperostelium Region K Region l

C. Raperostelium (Supplemental material S9) 860 870 Raperostelium Hagiwaraea Region K Region l

D. Tieghemostelium (Supplemental material S10) 240 250 Tieghemostelium Hagiwaraea Raperostelium Region G Region I

E. Coremiostelium (Supplemental material S11) 200 210 Coremiostelium Speleostelium Tieghemostelium Hagiwaraea Raperostelium Dictyostelium Polysphondylium Region A Region K

F. Synstelium (Supplemental material S12) 280 290 Synstelium Cavenderia Acytostelium Rostrostelium Heterostelium Speleostelium Tieghemostelium Hagiwaraea Raperostelium Polysphondylium Dictyostelium Coremiostelium Region G Region I

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D E F /r /r ///rrr r ~ ~~~ ~ • r ~i ~~~~~~~~ ~ ~` ••~, E ~ rr ~~~i ii ~~~~~~ `` ` • ~,~,~, EEE ~~ r rii \` ~ ``~~ ~~,~, . • ~EE Mj ~~ rr\`\` ~~~ ~~~~ ~~ . . ••• ~~MjMjMj ~~~ r\` ~~ ~~ ~ . ~ •• ~MjMj ~~ ~i ~ ! )-_' ~~ ~i~ i~i ~ ~ ~ !! )-)-_'_' ~ ~,' ///(((~~~ ~ ~. ~~ ~ ~ ~ r . 1 ~V ;1t/ j i i !~ )-_' ~• f ~,'~~,' //////(((///(((~~~~~~(((~~~~~~ ~.~. ~~~ rrr ~V~V ;1;1 ;1t/ t/ t/ jj ~~ ~ ~•rr .. ff f 1 1~V1 ~,'~ ;1;1 t/ t/ //////((((((~~~~~~ ~ ~ j~. ~~ ~•~• . ff 11 ~~ ~*~ •~ • ~• ~~~~ ~~•** ~•~•~•~ .. • • ~~ • ~*•• ~•~~•~~ ...... • .... • ~~ •• •• ~; •• ~~;;r, ~ •• '* ~;rr,, ~~ •• '*'*'* :; ~ 1r - , ~ ~•~ ,~ ~ ~ •j ~ '*'*.~t. ~ :; ~ 111 - - - - - ~~~ •~••~ ~ ,~,~,~ ~~~~ ~ ~ jjj j j ~~ .~.~t.t.t. ~~~ y::: ;;; ~~~ ~ ~t_~ ••~ ~ ~~ ~ .~ rV yy ~t_~~t_~ ~~~ ~ ~ rVrVrV `l y '•'~t_~ ~~ ~ rVrV ``ll ''•'•'•' `l '•'•' 4 ' ~ 44 '' ~~~ 4 ' ~~ G H ~~~ ~'~~'~~'~~'~ ~~~ ~ ~ ~ ~~~I GGG ~~~~-~----~ ~~ ~ ~ HHH ~~~ ~~~~~ F1~. 12-34. Dicryostelium rhizopodium Raper and Fennell. A. Sorocarps in a streak culture FFF1~.1~.1~.1~. 12-34.12-34. Dicryostelium DicryosteliumDicryostelium rhizopodiumrhizopodium RaperRaper andand Fennell.Fennell.Fennell. A.A. SorocarpsSorocarps ininin aa streakstreakstreak culturecultureculture of E.12-34. coli. SoriDicryosteliumDicryostelium on erect stalks rhizopodium appear Rapergray; those and Fennell.Fennell. that have A. collapsed Sorocarps on inin agar a streakstreak appear cultureculture dark ooofff E. E. E. coli.coli.coli. SoriSoriSori onon erecterecterect stalksstalksstalks appearappear gray;gray;gray; those thosethose thatthatthat havehave collapsedcollapsedcollapsed onon agaragar appearappear darkdark and larger.coli.coli. SoriSorix 5. on B. erecterect Spores stalksstalks containing appear gray; gray;obvious thosethose polar thatthat granules have collapsedcollapsed (transmitted on agar light). appear x 1150.dark anananddd larger.larger.larger. xxx 5.5. B. B. SporesSpores containingcontainingcontaining obviousobvious polarpolarpolar granulesgranulesgranules (transmitted (transmitted(transmitted light).light).light). xx 1150.1150. C. Vegetativelarger.larger. 5.myxamoebae B. Spores containing containingfeeding at obviouscolony edge.polarpolar granulesgranulesx 525. (transmitted(transmittedD. Two characteristic light).light). x 1150.aggre- CC.. VegetativeVegetativeVegetative myxamoebaemyxamoebae feedingfeedingfeeding atatat colonycolony edge.edge. xx 525.525. D.D. TwoTwo characteristiccharacteristiccharacteristic aggre-aggre-aggre- Cgations.. VegetativeVegetative x 8. E.myxamoebae Larger aggregation; feedingfeeding atatnote colony that inflowing edge. x streams525. D. have Two broken characteristiccharacteristic up in subcentral aggre-aggre- gations.gations.gations.gations. xxx 8.8.E. E. E. Larger Larger aggregation; aggregation;aggregation; notenote note that thatthat inflowing inflowinginflowing streams streams have have broken broken up up in inin subcentral subcentralsubcentral area. Fruiting8. byLarger such dissociatedaggregation;aggregation; myxamoebae notenote thatthat inflowinginflowing must awaitstreams emergence have broken of upnew inin centers. subcentralsubcentral x aaarea.rea.rea.rea. FruitingFruitingFruiting byby suchsuch dissociateddissociateddissociated myxamoebaemyxamoebae mustmust awaitawaitawait emergenceemergence ofof newnew centers.centers.centers. xx 8. F. FruitingFruitingApical area by suchof developing dissociateddissociated sorocarp myxamoebae showing must terminally awaitawait emergenceexpanded sorophore of new centers.centers. sheath andx 888... F. F. F. Apical Apical areaareaarea ofof developing developing sorocarpsorocarpsorocarp showingshowing terminallyterminallyterminally expandedexpanded sorophoresorophore sheathsheathsheath andand chazacteristicApical areaarea orientation of developing of myxamoebae sorocarpsorocarp showing that surround terminallyterminally it. expandedx 300. G. sorophore Crampon sheathsheath base andand ccchazacteristichazacteristichazacteristic orientationorientationorientation ofof myxamoebaemyxamoebae thatthatthat surroundsurroundsurround it.it.it. xx 300.300. G.G. CramponCrampon basebase anandd shazacteristicorophorehazacteristic showing orientationorientation similar of differentiation myxamoebae ofthatthat constituent surroundsurround cells. it.it. x x300. 300. G. H. Crampon Clustered basebase sorogens and ssssorophoreorophore showing showing similarsimilarsimilar differentiationdifferentiationdifferentiation ofof constituent constituentconstituent cells. cells.cells. xx 300.300. H. H. Clustered ClusteredClustered sorogenssorogens aorophorerising from showing a single similarsimilar aggregation. differentiationdifferentiation x 30. of 1. constituentconstituent Mature sorocarps cells.cells. x of 300. the H.same ClusteredClustered strain and sorogens young aaarisingrisingrisingrising fromfrom aa singlesinglesingle aggregation.aggregation.aggregation. xx 30.30. 1. 1.1. MatureMature sorocarpssorocarpssorocarps ofof the thethe samesame strainstrainstrain andand youngyoung sorogensfrom along a singlesingle colony aggregation.aggregation. edge (below). x 30.x 8. 1.1. (Reassembled Mature sorocarpssorocarps from of Raper thethe same and Fennell,strainstrain and 1967; young see ssorogensorogens alongalongalong colonycolony edgeedge (below). (below). xx 8.8. (Reassembled (Reassembled from from RaperRaper an and Fennell, see saorogenslso Fig. along 8-18) colony edge (below). x 8. (Reassembled from Raper anddd Fennell,Fennell, Fennell, 1967; 1967;1967; see see see aaalsolsolsolso Fig. Fig.Fig.Fig. 8-18) 8-18)8-18) Figure13

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,t, ,tt~ ~ .--. ------zzz ~~ ~ 1 ~. ~~~~~~ ~~~ 1 1 ~.~.~. T TT `,`, `,`, ~;~;~; ,_ ,__ `~ ~ r `~ ~ r ``~~ ~~ ~. •~ r r s~. •~ ~•~ S~ - s s . S~ - - - S~S~ ":a `'~ - - ":a":a" :a`'~ `'~`'~ ------HH II JJ Ft~. 12-40. Dicryostelium lacteum van Tieghem. A. Sorocarps photographed by surface light FFt~.t~. 12-40. 12-40. Dicryostelium Dicryostelium lacteum lacteum van van Tieghem. Tieghem. A. A. Sorocarps Sorocarps photographed photographed by by surface surface light light Fot~.n low 12-40.-nutrient Dicryostelium agar with Escherichia lacteum van coli Tieghem. B/r. x A.14. Sorocarps B. Vegetative photographed myxamoebae by surfacefeeding light onon low low-nutrient-nutrient agar agar with with Escherichia Escherichia coli coli B/r. B/r. x x 14.14. B. B. Vegetative Vegetative myxamoebae myxamoebae feeding feeding oonn low E. coli;-nutrient note nuclei,agar with contractile Escherichia vacuoles, coli andB/r. food x 14.vacuoles B. Vegetative containing myxamoebae bacteria. x 900. feeding onon E. E. coli; coli; note note nuclei, nuclei, contractile contractile vacuoles, vacuoles, and and food food vacuoles vacuoles containing containing bacteria. bacteria. x x 900. 900. oCn. E. Small, coli; moundnote nuclei,-like aggregations contractile formedvacuoles, without and foodstream vacuoles formation containing on weak bacteria. hay infusion x 900. CC. .Small, Small, mound mound-like-like aggregations aggregations formed formed without without stream stream formation formation on on weak weak hay hay infusion infusion Ca.gar. Small, x 14. mound Insert,-like aggregation aggregations via streamsformed onwithout agar withstream very formation low nutrient on (O.1L-P/6).weak hay infusion x agar.agar. xx 14.14. Insert, Insert, aggregation aggregation via via streams streams on on agar agar with with very very low low nutrient nutrient (O.1L-P/6). (O.1L-P/6). xx a8gar.. D. Multiplex 14. Insert, sorogens aggregation arising from via a streamssingle small on agaraggregation. with very x 70.low E. nutrient Three aggregation(O.1L-P/6). x 8.8 D.. D. Multiple Multiple sorogens sorogens arising arising from from a asingle single small small aggregation. aggregation. x x 70. 70. E. E. Three Three aggregation aggregation 8a.reas from which mutliple, thin sorogens are developing.aggregation. x 8. F. A singlex 70. sorogen E. Three in processaggregation areasareasD. from Multiple from which which sorogens mutliple, mutliple, arising thin thin sorogens sorogens from a are single are developing. developing. small x x8. 8. F. F. A A single single sorogen sorogen in in process process of fruiting. x 70. G. Typical sorophore composed of a single tier of vacuolate cells. x oafreaso ffruiting. fruiting. from which xx 70.70. mutliple, G. G. Typical Typical thin sorophore sorophoresorogens composed arecomposed developing. of of a asingle singlex 8. tier F.tier Aof of singlevacuolate vacuolate sorogen cells. cells. in processxx 240. H. Bases of clustered sorocarps showing cellular structure. x 240. I. Bases of sorocarps 2o40.2f 40.fruiting. H. H. Bases Bases x of of 70.clustered clustered G. Typical sorocarps sorocarps sorophore showing showing cellularcomposed cellular structure. structure. of a singlex x 240. 240. tier I. I. Basesof Bases vacuolate of of sorocarps sorocarps cells. x photographed to show expanded aprons of slime that anchor structures to substrate. x 70. p2hotographedp40.hotographed H. Bases to toof show clusteredshow expanded expanded sorocarps aprons aprons showing of of slime slime cellular that that an an chorstructure.chor structures structures x 240. to to substrate. I.substrate. Bases of x xsorocarps 70.70. J. Globose spores characteristic of this species. x 750 Jp.Jhotographed .Globose Globose spores spores to showcharacteristic characteristic expanded of of thisaprons this species. species. of slime x x750 750that anchor structures to substrate. x 70. J. Globose spores characteristic of this species. x 750 J • Figure15 ~ ~ . ~ s

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FiG. 12-27. Dictyostelium polycephalum Raper. A. Coremiform sorocarps and newly formed pseudoplasmodia on an agar block viewed from the side. Culture growing in association with Klebsiella pneumoniae and Dematium nigrum on 0.5% glucose, 0.1% peptone agar. x 25. B. Sorocarps formed in association with K. pneumoniae on agar containing galactose (0.5%) and asparagine (0.2%) in aclay-covered Petri dish (see text). x 25. C. Spores, showing characteristic shape and commonly a single polar granule. x 900. D. Myxamoebae beneath coverglass; note empty spore case (arrow) and how it was broken to release the protoplast. x 900. E. A developing cell aggregation showing typical radial pattern. x 9. F. Aggregation at edge of a bacterial streak; note ridges that reflect waves of converging myxamoebae. x 16.5. G. Aggregations in process of formation (left) and delicate migrating pseudoplasmodia emerging from two centers of aggregation (right). x 8. H. Two typical migrating pseudo- plasmodia. x 16.5. I. Migrating pseudoplasmodium moving through a colony of Absidia; note its minimal support. x 8. (Rearranged in part from Raper, 1956)