Francisco Pando

The Echinosteliales is a small group (c. 20 spp., 3 gen.) that comprises the smallest Myxomycetes species, and are caracterized by having stipitated, multisporic sporocarps (except Echinostelium bisporum), subhypothalic development, and protoplasmodia. Most of the species are corticolous and, despited being scant collected, it is likely that they are distributed worldwide.

Due to their minute size, and the dificulties involved in their collection, the majority of species have been described recently (13 out of the 17 species currenlty accepted were described after 1960). The key paper in this group is the account on Echinostelium by Whitney (1980). Other relevant papers for the understanding of the Echinosteliales are Kowalski & Hinchee (1972), Alexopoulos & Brooks (1971), and Frederick & al. (1986). As part of our studies on Iberian coticolous myxomycetes, (Pando, 1989; 1990; 1997) and for the Flora Mycologica Iberica project (Lado & Pando, 1997), we had the oportunity to collect and study all but two of the know Echinostelium species, some of them abundanly, others found for the first time ouside the type locality, and one was newly described. The two Clastoderma species were also found. Since the begining DELTA (Dalltwitz, 1980; Dalltwitz & al., 1993) was used rutinarily as a taxonomic tool, especially to prepare the keys to species and the descriptions in Spanish and English.

Our goal with this paper was 1) to complete the revision of the group studing the few species either not found by us or described after 1980, or both; 2) to expand and improve the descriptive database in DELTA format 3); generate detailed taxonomic description using the DELTA database 4) illustrate the database to assist interactive identifications with pictures of characters and taxa; and 5) present the compiled information readily available.

Methodology

The preparation of the character set, involved the making of perliminar list based in our own experience of the group and the revision of floras and monographs. Upon this peliminar list, descritive phrases were compliled from selected works, such as Martin & Alexopoulos (1969), Farr (1976) and several papers by Nannenga-Bremekamp (1965, 1967, 1971). The first "operational" character set was synthesize from this information. Terminology was fixed with the aid of Font Quer (1953), Stearn (1983) and Hawksworth & al. (1995). Further refinement in the wording of character features and states was introduce to improve clarity of descriptions and printed keys.

To avoid "concept drift", operational definitions were prepared for most characters and their stats, and they were incorporated as "character notes" in the DELTA database (appendix 1). In some cases, reference pictures substitute text definitions when these resulted too cumbersome to use or to meassure.

Some characters, of little use within the Echinosteliales were introduce for sake of compatibility when other order species are incorporated in the DELTA database. Some examples of these are, sporphore type (1), capillitium type (37), plasmodium type (86) or numerous states for color characters.

Colors were codified according to the ISCC-NBS Color-Name Charts Illustrated with Centroid Colors (Anonymous, 1976).

DELTA character dependencies were defined where appropiate.

Results and Discussion

A terminology to describe characters explicitly has been set up. This is specially so in the case of capillitium characters. Taxonomic relevance of capillitium has been never disputed, and it has been use by all author. However, its descriptive information has remained hardly formalized, making it very difficult to use consistenly. A clearly defined reference character set would improve comunication among myxomycetologists, and eliminate redundant work.

All species can be distinguised from any other in at least two characters.

Echinostelium vanderpoelii was sinonimized to E. apitectum on the basis that, first it could not be distinguished using INKEY, and second, after a careful revision of the previously considered diagnostic characters (Pando, 1997). In a like manner, Clastoderma dyctyosporum, and C. microcarpa have been synonymyzed to C. debaryanum and C. pachypus, respectively.

The present work, beyond its taxonomical contribution, explores the possibilities of an still little known method and its associated tools, which, will impact the taxonomist's work as well as the way he or she communicates biodiversity knowledge.

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 Last update: 15 July 1999