A new species of Lamproderma (Myxomycetes) from Costa Rica

1 A new species of Lamproderma (Myxomycetes) from Costa Rica

Gabriel Moreno Departamento de Biología Vegetal (Botánica), Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain. Email: [email protected]

Carlos Rojas Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, USA. Email: [email protected] Telephone (479) 575-7393 Fax: (479) 575-4936

Steven L. Stephenson Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, USA. Email: [email protected]

Harald Singer Departamento de Biología Vegetal (Botánica), Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain. Email: [email protected]

2 Abstract: Lamproderma magniretisporum, a new species of myxomycete from Costa Rica, is described and illustrated. This new species is characterized by its lignicolous habitat, long stalk, dark radial capillitium, large spores and reticulate spore ornamentation. The stability of the taxonomic characters of L. magniretisporum is supported by two well developed collections. The morphology of the sporocarp was subjected to detailed study with both the light microscope and the scanning electron microscope. Micrographs of all relevant features are presented.

Taxonomic novelties: Lamproderma magniretisporum G. Moreno, C. Rojas, S.L. Stephenson & H. Singer

Key words: Myxomycetes, Stemonitales, taxonomy, Central America

Introduction

The genus Lamproderma was created by Rostafinski (1873) for Lamproderma columbinum (Pers.) Rostaf. and placed in the family Stemonitidaceae Fr. of the class Myxomycetes. This treatment is currently still followed by Kirk et al. (2001). According to Martin and Alexopoulos (1969), this genus is characterized by the following features: sporocarps sporangiate; membranous, persistent and usually iridescent peridium; columella generally present and occupying one third to two thirds of the height of the sporotheca; capillitium originating mainly from the apex of the columella and frequently paler towards the periphery; spores dark in mass. The genus Lamproderma is particularly widespread and diverse in alpine snowbank habitats, but not all species are nivicolous. Some species can also be found in

3 other habitats at lower elevations, where they usually occur in association with wood or litter. Lado (2001) listed 41 species of Lamproderma. Four years later, HernándezCrespo and Lado (2005) recognized a total of approximately 44 species from the approximately 129 described taxa, a total that included a large percentage of forms and varieties. Only six species of Lamproderma have been described as having reticulate spores. These are Lamproderma australiense S.L. Stephenson, G. Moreno & H. Singer; L. cribrarioides (Fr.) R.E. Fr.; L. meyerianum (Y. Yamam.) G. Moreno, Singer & Illana; L. reticulosporum Gilert; L. retisporum (Dhillon & Nann.-Bremek.) T.N. Lakh. & K.G. Mukerji; and L. retirugisporum G. Moreno, H. Singer, Illana & A. Sánchez. It should be noted that L. australiense was published originally as L. australiensis. However, in accordance with international nomenclatural rules, the specific epithets of species of Lamproderma must be treated as neuter, since the word “Lamproderma" is actually Greek. This means that the correct name for L. australiensis is L. australiense. The same situation would apply to L. retispora, for which the correct name is actually L. retisporum. The corrected names are used throughout this paper. Hagelstein (1942) created the genus Elaeomyxa Hagelst. to include those species that are characterized by the presence of orange to yellow oleous substances in the stalk, capillitium or peridium. Elaeomyxa is morphologically close to Lamproderma, and two species (L. reticulosporum and L. australiense) originally placed in the latter genus have been recently transferred to Elaeomyxa (Moreno et al. 2008). Lamproderma magniretisporum, the new species described herein, is compared with these two species. L. reticulosporum is the first member of the genus with reticulate spore ornamentation to be reported from the Neotropics.

4 Materials and methods The two specimens upon which the new species is based developed in the field under natural conditions. Once collected, they were brought back to the laboratory, air-dried and then glued in small boxes for permanent storage in the herbarium of the University of Arkansas (UARK). Later, portions of both specimens were sent to the senior author for detailed studies with both the light microscope and the scanning electron microscope. Duplicates (slides) of these specimens are deposited in the Herbarium AH of the Department of Plant Biology, University of Alcalá, Madrid, Spain. Sporocarps from the two specimens were mounted in Hoyer’s medium. Spores, including surface structures such as spines or warts, were measured with an oil immersion lens. For ultramicroscopic studies, the material was rehydrated in concentrated ammonium hydroxide (28-30%) for 30 minutes, dehydrated in aqueous ethanol (70%) for 30 minutes, fixed for two hours in pure ethylene glycol dimethyl ether (= 1,2–dimethoxymethane) and finally immersed in pure acetone for at least two hours. This was followed by critical point drying and sputtering with gold-palladium.

Description

Lamproderma magniretisporum G. Moreno, C. Rojas, S.L. Stephenson & H. Singer, sp. nov. Latin diagnosis: Sporocarpia stipitata, 2.2-3 × 0.6-1 mm, dispersa vel parvis coloniis graegariis producentibus. Sporotheca globosa vel subglobosa, 0.6-1 mm in diam. Peridium griseum vel griseo-chalybeus, in summo irregulariter diffractus et parvis laminis producente, ad basim persistente. Stipes 1.5-2.5 mm, cylindricus, nigrum vel obscure rubro-brunneum. Columella stipite concolorata, fere 1/3 altitudinis stipitis

5 occupante. Filamenta capillitii 2-5 µm lata, obscure rubro-brunnea sed in summo clariora, rigida, parallela, lateraliter in ramos divisa, ramis ex filamentis capillitii ad apicem biarticulatis efformatis. Sporae 16-18 µm, in cumulo obscurae, reticulatae, reticulum ex variabilibus latisque maculibus efformato. Specimina: Costa Rica, San José, Cerro de la Muerte, ad lignum emortuum, in silva quercina magnae altidunis latitude N 9.5647, longitude W 83.7422. 13-II-2007, coll. C. Rojas 1952 [UARK 35682] Holotypus. Photo in AH 31857 conservata Isotypus. Idem, coll. C. Rojas 1953 [UARK 35683]. Photo in AH 31858 conservata.

Etymology: magniretisporum, in reference to its large, reticulate spores.

Specimens examined: Costa Rica, San José, Cerro de la Muerte, on a decaying log at an intermediate stage of decomposition, high-elevation oak forest, 9.5647 N, -83.7422 W, 3200 m asl., on Quercus costaricensis Liebm., leg. C. Rojas 1952 [UARK 35682], 13. II. 2007, Holotypus. Slide in AH 31857 Isotypus. Idem, coll. C. Rojas 1953 [UARK 35683]. Slide in AH 31858. The two collections occurred on the same log approximately 4 m apart.

Sporocarps stalked, 2.2-3 × 0.6-1 mm, scattered or forming small gregarious colonies (Fig. 1a). Sporotheca globose to subglobose, 0.6-1 mm in diam. (Fig. 1b). Peridium grey to steel grey, iridescent (Fig. 1b), irregularly breaking at the apex into small plates (Fig. 1b), sometimes persisting at the base as a more or less petaloid cup (Fig. 1b). Stalk 1.52.5 mm long, 2-3 times longer than the diameter of the sporotheca (Fig. 1c), cylindrical, broader towards the base, black to dark reddish brown (Fig. 1c). Columella concolorous with the stalk and occupying approximately 1/3 of the height of the sporotheca (Fig.

6 1d). Capillitium threads 2-5 µm in diam., dark reddish brown with paler tips under the LM, rigid, parallel, laterally branched and bearing scattered nodules up to 7 µm in diam. (Fig. 1h), concolorous with the capillitium, developing along the entire length of the columella (Fig. 1e) and with dichotomously branched capillitial tips (Fig. 1f). Spores dark in mass, 16-18 µm in diam., reticulate, with a reticulum composed of broad meshes of variable morphology (Fig. 1g). Observation with SEM confirms the presence of a reticulate spore ornamentation (Figs. 1i-1j) with meshes separated by solid walls up to 1 µm high and without perforations (Fig. 1k).

Discussion

Lamproderma magniretisporum is characterized by its large sporocarps (2.2-3 × 0.6-1 mm), prominent stalk (1.5-2.5 mm), large reticulate spores (16-18 µm) and its occurrence on decaying wood. Other described species of Lamproderma with reticulate spores are L. australiense S.L. Stephenson, G. Moreno & H. Singer; L. cribrarioides (Fr.) R.E. Fr.; L. meyerianum (Y. Yamam.) G. Moreno, Singer & Illana; L. reticulosporum Gilert; L. retisporum (Dhillon & Nann.-Bremek.) T.N. Lakh. & K.G. Mukerji; and L. retirugisporum G. Moreno, H. Singer, Illana & A. Sánchez. Lamproderma magniretispora differs from all of these in one or more respects. Lamproderma cribrarioides, a nivicolous species that has been misinterpreted for years, is characterized by sporocarps 1-2.5 mm total height, very dark, ovoid to rarely globose sporotheca, 0.5-1 × 1-1.5 mm, a peridium persisting in the form of small patches that remain attached to the dichotomously branched tips of the capillitium, capillitium abundant, uniformly dark and with funnel-shaped or Y-shaped free ends,

7 reticulate spores 12-15 µm in diam. with broad meshes and high ridges (1-1.5 µm). The taxonomic treatment of this species has been thoroughly discussed by Singer et al. (2001, 2003) and Poulain et al. (2003). Subsequently, Sánchez et al. (2007) distinguished two varieties: L. cribrarioides var. cribrarioides for species with reticulate spores and L. cribrarioides var. carestiae (Ces. & De Not.) G. Moreno & H. Singer for collections with spinose, spinulose, crested or subreticulate spores. Lamproderma retirugisporum is a nivicolous species that is widely distributed in Europe. It is characterized by sporocarps 0.5-2.5 mm total height, with green to violaceous sporothecae 0.5-1.5 mm diam., rigid and dark capillitium, spores 13-15 µm diam., completely reticulate with broad meshes and high ridges [1-1.5(-2) µm]. The epithet retirugisporum has been proposed for this species, which previously has been confused with L. cribrarioides (Singer et al. 2003). Lamproderma meyerianum is a nivicolous species described from Japan. It is characterized by stalked sporocarps 0.8-2.2 mm total height, globose, blue to violaceous coloured iridescent sporothecae 0.8-1.8 mm diam., peridium persistent in the lower half, stalk short when compared with the diameter of the sporotheca, capillitium abundant, composed of thin, hyaline threads, large spores (16-18 µm diam), with an ornamentation formed by an almost complete to complete reticulum with small and irregular meshes (Moreno et al. 2005). Lamproderma retisporum, described originally as Collaria retispora Dhillon & Nann.-Bremek., was collected in India on the decaying wood of Quercus. This species is characterized by its small sporocarps up to 1.5 mm high and 0.32 mm diam., and small spores (6-8 µm in diam.) with a delicate, small-meshed capillitium (Dhillon and Nannenga-Bremekamp, 1977).

8 Lamproderma reticulosporum is a species known only from the type locality, western Java in Indonesia, where it was collected from the bark of a huge evergreen tree (Burseraceae?) with a moss-covered trunk (Gilert and Neuendorf; 1991). The species was later transferred to the genus Elaeomyxa as E. reticulospora (Gilert) G. Moreno & S.L. Stephenson. It is characterized by smaller sporothecae (0.3-0.4 mm in diam.), a stalk longer than the diam. of the sporotheca, a peridium covered by distinct patches similar to the condition found in L. gulielmae Meylan, a capillitium with regularly distributed fusiform to globose swellings with yellow to orange oleous contents, small spores (9-10 µm diam.) and a distribution apparently limited to the tropics (Moreno et al. 2008). Lamproderma australiense, also known only from its type locality, was described from Australia, where it occurred on litter in association with bryophytes in an alpine snowbank habitat. Like L. reticulosporum, this species was later transferred to the genus Elaeomyxa as E. australiensis (S.L. Stephenson, G. Moreno & H. Singer) G. Moreno & S.L. Stephenson. It is characterized by larger sporothecae (0.7-1.3 mm diam.), a stalk that is the same size or shorter than the diameter of the sporotheca, a peridium either without patches or only occasionally covered by small pronounced patches, a capillitium with abundant fusiform, very elongated swollen nodules with yellow to orange oleous contents, the nodules located mainly towards the columella, larger spores (10-12 µm diam.) and a distribution limited to alpine snowbank habitats (Stephenson et al. 2007, Moreno et al. 2008).

Key to the species of Lamproderma sensu lato that have reticulate spores:

9 1. Capillitium with yellow to orange oleous thickenings (Elaeomyxa Hagelst.) ……………………………………………………………………………………..…… 2 1'. Capillitium without yellow or orange oleous thickenings (Lamproderma Rostaf.) …………………………………………………………………………………….......... 3 2. Spores 9-10 µm; associated with bryophytes on the bark of tropical trees ………………………………………………………………......……… E. reticulospora 2'. Spores 10-12 µm; on moss-covered litter in alpine snowbank habitats …………………………………………………………………...…….... E. australiensis 3.

Nivicolous

and

thus

apparently

limited

to

alpine

snowbank

habitats

……………………………………………………………………...…......................…. 4 3'.

Not

nivicolous

and

thus

not

occurring

in

alpine

snowbank

habitats

………………………………………………………………………...………...……… 6 4. Sporotheca ovoid to rarely globose; very dark; peridium persisting in the form of small patches; capillitium with funnel- or Y-shaped free ends; spores 12-15 µm diam. ………………………………………………………………................... L. cribrarioides 4'. Sporotheca globose; peridium evanescent except at the base; capillitium without funnel- or Y-shaped free ends …………………………………...……………...……… 5 5. Capillitium consisting of thin and hyaline threads; spores 16-18 µm; with small, irregular meshes and low ridges ………………………………………… L. meyerianum 5'. Capillitium consisting of rigid and dark threads; spores 13-15 µm; with broad meshes, rigid and high ridges ……………….………………………... L. retirugisporum 6. Foliicolous and thus occurring on litter; with sporocarps up to 1.5 mm high and sporothecae 0.32 mm in diam.; spores 6-8 µm diam.; with a delicate and relatively indistinct reticulum consisting of small meshes …….………………….… L. retisporum

10 6'. Lignicolous and thus occurring on wood; with sporocarps up to 3.0 mm high and sporothecae 1.0 mm in diam.; spores 16-18 µm; with a prominent reticulum consisting of wide meshes ………………………………….……………….…. L. magniretisporum

Acknowledgments

We express our gratitude to Mr. D.W. Mitchell, for reviewing the manuscript and adding a number of useful comments, and to Mr. A. Priego and Mr. J.A. Pérez of the Electron Microscopy Service of the University of Alcalá de Henares for their invaluable help with the SEM. We also thank Luis Monje of the “Gabinete de Dibujo y Fotografía Científica” at the Universidad de Alcalá de Henares for help in the digital preparation of the photographs and to Dr. J. Rejos, curator of the AH herbarium. Finally, we would like to thank ACLA-P and Mr. Federico Valverde of the Cerro de la Muerte Biological Station in Costa Rica for their help in the field research process.

References

Dhillon SS, Nannenga-Bremekamp NE (1977) Notes on some myxomycetes from the north-western part of the Himalaya. P K Ned Akad C Biol, Amsterdam. Ser. C, 80(4): 257-266

Gilert E, Neuendorf M (1991) A new species of Lamproderma (Myxomycetes) found in Java. Nord. J. Bot. 10: 661-664

Hagelstein R (1942) A new genus of the Mycetozoa. Mycologia 34: 593-594

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Hernández-Crespo JC, Lado C (2005) An on-line nomenclatural information system of Eumycetozoa. http://www.nomen.eumycetozoa.com (10-IX-2008).

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Singer H, Moreno G, Illana C (2001). Nivicolous Myxomycetes from Tyrol (Austria). II. The genus Lamproderma. Oesterr. Z. Pilzk. 10: 25-42

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Figure 1. Lamproderma magniretispora Holotypus: a. Sporocarps. b. Detail of the sporotheca and dehiscence of the peridium. c. Detail of a sporocarp. d. Detail of the sporotheca and capillitium. e. Detail of the columella and insertion of the capillitium. f. Dichotomous capillitial tips as viewed by SEM. g. Reticulate spores. h. Capillitial nodules. i-j. Reticulate spores as viewed by SEM. k. Detail of spore ornamentation as viewed by SEM. Scale bars: a and b = 1 mm; c = 0.5 mm; d = 0.2 mm; e = 100 µm; f, g and h = 10 µm; and i, j and k = 2 µm.

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