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Mycologia, 95(1), 2003, pp. 124-127.
© 2003 by The Mycological Society of America

Reflections on the genus Vanakripa, and a description of V. ellipsoidea sp. nov


Clement K. M. Tsui 1
Teik-Khiang Goh
Kevin D. Hyde

     Centre for Research in Fungal Diversity, Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong, China

   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 TAXONOMY
 LITERATURE CITED
 

The genus Vanakripa (hyphomycetes) is reviewed based on the examination of type specimens, and V. ellipsoidea sp. nov. is described on submerged wood from Hong Kong. Vanakripa is characterized by punctiform sporodochial colonies, micronematous conidiogenous cells and pigmented conidia with vermiform separating cells. Vanakripa is compared with similar genera, and a synopsis of its morphological characters is provided.

Key words: aquatic fungi, freshwater, lignicolous, mitosporic fungi, systematics


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
TAXONOMY
 LITERATURE CITED
 
Submerged wood in freshwater environments supports a high diversity of fungi and several novel taxa have been described from tropical and subtropical regions (Hyde and Goh 1998Citation, Tsui et al 2001Citation). During our investigation of lignicolous fungi in freshwater habitats in Hong Kong (Tsui et al 2000Citation), we collected an interesting mitosporic fungus that we named Vanakripa sp. We examined type material of all Vanakripa species from National Mycological Herbarium of Canada (DAOM), and as a result accept three species in Vanakripa, including Vanakripa ellipsoidea sp. nov. described in this paper.


   TAXONOMY
TOP
 ABSTRACT
 INTRODUCTION
 TAXONOMY
LITERATURE CITED
 

Vanakripa ellipsoidea K. M. Tsui, Goh et K. D. Hyde, sp. nov. Figs. 1–12



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  		 FIGS. 1–12. Light (1, 2) and differential interference contrast micrographs of Vanakripa ellipsoidea (from holotype). 1, 2. Colonies on wood (light micrographs). 3–10. Conidia bearing vermiform separating cells. 11, 12. Separating cells with frills of detached conidiogenous cells. Scale bars: 1–2 = 300 µm, 3 = 70 µm, 4–12 = 20 µm

 
Coloniae in substrato naturali sporodochiales 150–180 µm diam. Conidiophora micronemata, cylindrica, aseptata, simplicia vel sparse ramosa, laevia, hyalina. Cellulae conidiogenae in conidiophoris incorporatae, terminales, determinatae, cylindricae. Cellulae separabiles 30–72 x 11–16 µm, vermiformes, clavatae vel hyalinae. Conidia 33–42 x 20–25 µm, acrogena, solitaria, aseptata, ellipsoidea vel late-fusiformia, laevia, brunnea vel atra. Conidiorum secessio rhexolytica.

Colonies on natural substratum sporodochial, 150–180 µm diam, scattered, black (Figs. 1, 2). Mycelium mostly immersed in the substratum, composed of septate, hyaline hyphae. Conidiophores micronematous, ca 15–20 x 2 µm, hypha-like, short cylindrical, aseptate, simple or sparsely branched, smooth, hyaline (Figs. 1, 2). Conidiogenous cells integrated, terminal, determinate. Separating cells 30–72 x 11–16 µm, hyaline, clavate to vermiform. Conidia 33–42 x 20–25 µm, acrogenous, solitary, ellipsoid to broadly fusiform, with a rounded tip, smooth, dark brown to black, aseptate, smooth-walled (Figs. 3–10). Conidial secession rhexolytic (Figs. 11, 12). Single spore isolation was attempted but not successful.

Etymology. The Latin ellipsoidea, in reference to the shape of the conidia.

Specimen examined. CHINA. HONG KONG: Tai Po, Bride's Pool, on submerged wood, Mar 1999, K. M. Tsui, KM296 (HKU(M) 12378), ibid., Sai Kung, Hang Cho Shui, on submerged wood, Sep 1998, K. M. Tsui, KM 296 (HKU(M) 12234).

Vanakripa parva Bhat, W. B. Kendr. et Nag Raj, Mycotaxon 49:77 (1993) Figs. 13–18



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  		 FIGS. 13–18. Light (13) and differential interference contrast micrographs of Vanakripa parva (from holotype). 13. Colonies on wood. 14–18. Conidia bearing separating cells (arrowed). 19–22. Vanakripa gigaspora (from holotype). 19. Conidia bearing vermiform separating cells (arrowed). 20–22. Uniseptate conidia. Scale bars: 13 = 500 µm, 14, 17, 18 = 8 µm, 15 = 10 µm, 16 = 6 µm, 19, 20 = 18 µm, 21, 22 = 15 µm

 
Colonies on natural substratum sporodochial, punctiform, scattered, black (Fig. 13). Conidiophores micronematous, simple, indistinct, borne on superficial hyphae. Conidiogenous cells integrated, terminal. Separating cells 20–40 x 4–5 µm, hyaline, vermiform (Figs. 14–16). Conidia acrogenous, 7–10 x 4–6 µm, ovoid to broadly fusiform, smooth, brown to dark brown, aseptate (Figs. 17, 18). Conidial secession rhexolytic.

Specimen examined. INDIA. GOA STATE: Cotigao Wildlife Sanctuary, on dead twig, 28 July 1991, D. J. Bhat (DAOM 214617, HOLOTYPE).

Vanakripa gigaspora Bhat, W. B. Kendr. et Nag Raj, Mycotaxon 49:76 (1993) (Figs. 19–22)

Colonies on natural substratum sporodochial, effuse, scattered, black. Conidiophores micronematous, indistinct, hyaline. Separating cells hyaline, vermiform, 18–70 x 6–8 µm, smooth (Figs. 19, 20). Conidia acrogenous, 33–40 x 19–23 µm, ellipsoidal to broadly fusiform, with a submedian septum, smooth, dark brown to black, basal cell pale brown (Figs. 21, 22). Conidial secession rhexolytic.

Specimen examined. INDIA. GOA STATE: Molem Wildlife Sanctuary, on dead twig, 30 Jul 1991, D. J. Bhat (DAOM 214616, HOLOTYPE).

Notes. Vanakripa currently includes V. gigaspora Bhat, W. B. Kendr. et Nag Raj and V. parva Bhat, W. B. Kendr. et Nag Raj (Bhat and Kendrick 1993Citation). Vanakripa ellipsoidea produces black conidia with hyaline, obpyriform separating cells and is a third species in the genus. Vanakripa ellipsoidea differs from V. gigaspora in having aseptate conidia, and is distinguished from V. parva in having ellipsoidal and consistently larger conidia.

We have examined type material of V. parva and V. ellipsoidea and considered that the obpyriform conidiogenous cells described by Bhat and Kendrick (1993)Citation do not in fact proliferate or produce conidia. It is possible that the conidiophores in Vanakripa are micronematous and barely distinguishable from the vegetative hyphae. The tips of conidiophores are then blown out to form separating cells which bear conidia (sensu Pirozynski 1963Citation). The separating cells may detach from the conidia during their release. However, further ontogeny studies are required to resolve the mechanism of conidia production. Conidium-bearing separating cells at the base of conidia are typically found in Beltrania Penz., Beltraniopsis Bat. & J. L. Bezerra and Beltraniella Subram. (Pirozynski 1963Citation), and have also been observed in Berkleasmium corticola (Karst.) Moore (Moore 1959Citation, Sharma 1980Citation), Canalisporium caribense (Hol.-Jech. et Mercado) Nawawi et Kuthub., C. elegans Nawawi & Kuthub. (Goh et al 1998Citation) and Oncopodium paspali R. F. Castañeda Ruíz, Guarro et Cano (Ruíz et al 1997)Citation. These taxa are commonly found in freshwater habitats (Goh et al 1998Citation, Tsui et al 2000Citation), and it would therefore be interesting to establish whether the vesiculate separating cells are adaptations for conidial dispersal and floatation.

Vanakripa resembles Berkleasmium Zobel, Canalisporium Nawawi & Kuthub. and Dictyosporium Corda under a stereomicroscope, in having punctiform, shiny sporodochial colonies on the natural substratum. These genera also have micronematous conidiophores and pigmented conidia. When examined under higher magnification, Berkleasmium and Canalisporium are, however, easily distinguished because their conidia are muriform (Moore 1959Citation, Goh et al 1998Citation). Dictyosporium is characterized by cheiroid conidia with multiple columns of cells, which lack separating cells attached at the base of conidia (Goh et al 1999Citation).


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  		TABLE I. A synopsis of described Vanakripa species

 

   ACKNOWLEDGMENTS
 
We are grateful to the curator of National Mycological Herbarium of Canada (DAOM) for the loan of type materials. K. M. Tsui would like to thank The University of Hong Kong for the award of a Postgraduate Studentship. Ken Wong, Helen Leung and Mr. A. Y. P. Lee are thanked for technical and photographic assistance.


   FOOTNOTES
 
1 Corresponding author, ckmtsui{at}graduate.hku.hk Back

Accepted for publication June 15, 2002.


   LITERATURE CITED
TOP
 ABSTRACT
 INTRODUCTION
 TAXONOMY
 LITERATURE CITED
 
Bhat DJ, Kendrick B., 1993 Twenty-five new conidial fungi from the Western Ghats and the Andaman Islands (India). Mycotaxon 49:19-90

Castañeda Ruíz RF, Guarro J, Cano J., 1997 Notes on conidial fungi. XI. Two new species of Cheiromoniophora and Oncopodium. Mycotaxon 61:319-326

Goh TK, Ho WH, Hyde KD, Whitton SR, Umali TE., 1998 New records and species of Canalisporium (Hyphomycetes), with a revision of the genus. Can J Bot 76:142-152

———, Hyde KD, Ho WH, Yanna, 1999 A revision of the genus Dictyosporium, with descriptions of three new species. Fungal Divers 2:65-100

Hyde KD, Goh TK., 1998 Fungi on submerged wood in Lake Barrine, north Queensland, Australia. Mycol Res 102:739-749

Moore RT., 1959 The genus Berkleasmium. Mycologia 51:734-739

Pirozynski KA., 1963 Beltrania and related genera. Mycol Pap 90:1-37

Sharma ND., 1980 Some additions to fungi of India. VIII. J Ind Bot 59:72-77

Tsui CKM, Goh TK, Hyde KD, Hodgkiss IJ., 2001 New species or records of Cacumisporium, Helicosporium, Monotosporella and Bahusutrabeeja on submerged wood in Hong Kong streams. Mycologia 93:389-397

———, Hyde KD, Hodgkiss IJ., 2000 Biodiversity of fungi on submerged wood in Hong Kong streams. Aquatic Microbial Ecology 21:289-298





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