Nidularium rolfianum Leme
Literature references:
Comments:
- Introduction
The Brazilian Atlantic Forest today is one of the most endangered ecosystems in the world (Ranta et al., 1998), and the high number of species endemic to the remaining forest fragments suggests that many species have already become extinct before discovery (Morellato & Haddad, 2000; Morawetz & Raedig, 2007).
An average of 15 new bromeliad species from Brazil were described yearly between l998-2002 (Leme, 2003), most apparently endemic and found in the remaining Atlantic Forest fragments. In the states of Pernambuco and Alagoas, Northeastern Brazil, where the Atlantic Forest is most depleted, and remaining fragments represent
only 4.89% of the original forest area (Silva & Casteleti, 2005), 22 new endemic bromeliad taxa have been described in the past 10 years. This represents 23.65% of
all known regional species (Leme & Siqueira-Filho, 2007). In contrast, Morawetz & Raedig (2007) estimate a loss of 100 narrowly endemic angiosperm species per year, facing the high rate of deforestation in the Neotropics. These examples highlight our rudimentary knowledge of Atlantic Forest biodiversiry and underscore the importance
of taxonomy as a basic tool for conservation and for assessing biodiversity patterns (Mayo et al., 2000). Thus, one goal of the modern taxonomists, documentation of species diversity is trapped in a race against time ordained by habitat destruction and requires activism in "conservation-taxonomy''.
Nominal extinction
In the past few years, there have been numerous taxonomic studies of the Bromeliaceae. A growing number of scientists in Brazil and overseas are working to
unravel the diversity of the family and more precisely define conceptual taxon limits and phylogeny. As with most revisionary studies, a need will arise for nomenclatural
changes including new names, new combinations, revalidations, synonyms, etc., that are promptly dealt with so as to refect the different taxonomic hypotheses that are
proposed.
When new taxonomic hypotheses lead to misguided nomenclatural changes, especially when names of taxa are invalidated, species may become nominally extinct. Nominal species extinction, in contrast to bona fide extinction, is abstract and hypothetical, involving the designation of incorrect synonyms at the specific or infraspecific level (Leme, 2003). For example, in a new taxonomic treatment, two or more species are reduced to heterotypic synonyms of one taxon. Due to an error, the newly synonymized taxa no longer exist for all practical purposes.
Overall, the hypotheses and understanding that we have concerning a given phenomenon do not alter the phenomenon itself. Using the same line of reasoning, the
incorrect grouping of one or more taxa under a single epithet does not make these taxa disappear as biological entities. However, due to nominal extinction, taxa may become really extinct if they are no longer the focus of conservation and political decisions and actions. In other words, erroneous nominal extinction may enhance rhe likelihood of bona fide extinction, and in the case of the Bromeliaceae in the Brazilian Atlantic Forest, it may lead to the loss of associated flora and fauna, magnifying biodiversity loss.
Nominal extinction in "Flora de Sao Paulo" treatment
In this day and age, we cannot improve taxonomic studies of the Bromeliaceae if we do not make an effort to do field research and adopt a new philosophy of collecting botanical samples. As recommended by Brown et al. (1993), bromeliad taxonomists should concentrate on the reassessment and correlation of taxonomic traits, identifying new or under-utilized characters that provide new data and contribute to constructing a more natural system. However, as highlighted by Brown et al. (2008) some of the taxonomic concepts adopted by the recently published taxonomical treatment of Bromeliaceae in the "Flora Fanerogamica do Estado de Sao Paulo" (Wanderley & Martins, 2007) are contrary to the mainstream views of the Bromeliaceae research community since it neither provided new data, nor a data based justification, to explain the maintenance of older arguably artificial generic concepts for the family, over more recent revisionary changes that are based on focused, systematic monographic study.
In addition, the treatment of Bromeliaceae in the "Flora de Sao Paulo" provides some typical examples of bromeliad taxa that were made nominally extinct. One example involves N. krisgreeniae Leme, in the chapter on Nidularium (Moreira et al., 2007), where taxonomic information available in the literature was neglected and, more importantly, where the taxonomic decisions provided were not based on new tangibly produced data. Here the authors designated N. krisgreeniae as a new synonym of N. amazonicum (Baker) Linden & E. Morren ex Lindm. based solely on the argument that the first lies within the range of morphological variation of the latter. They also considered N. amazonicum var paulistanumWand. & B. A. Moreira to be a "new synonym" of the typical N. amazonicum, despite the fact that this variety had previously been considered a synonym of N. krisgreeniae by Luther (2001) and Leme (2002).
The multiple features that justify the segregation of N. krisgreeniae from N. amazonicum are explicitly provided and illustrated by Leme (2000). Both species, each with distinct geographical range, can be easily differentiated even when sterile by comparing rosette conformation, leaf texture and venation. Other sources of data (e. g., pollen and stigma microstructure, cladistic analysis of morphological data) that distinguish these species from each other are also provided by Halbritter & Till (1998), Gortan &Till (1998) and Brown & Leme (2000). Thus, N. krisgreeniae was made nominally extinguished by Moreira et al. (2007). Concerning N. amazonicum var paulistanum, the long explanation justifying its inclusion in the synonymy of N. krisgreeniae can be accessed in Leme (2002).
Synonymizing of taxa should not be based only on vague arguments like "there is insufficient material available to confirm the trait attributed to the species" or "species
X lies within the range of morphological variation of species Y”. We must remember that the inability to perceive certain differences and phenomena is sometimes typical
of the observer and occasionally stems from an ideological source. But based on the precautionary principle, if there are no new data and uncertainty still reigns, we must
abstain from making changes that can lead to a negative result (i.e., nominal extinction) and indisputable consequences in the real world.
New Nidularium species
Moreira et al. (2007) missed the opportunity to contribute to our understanding of Nidularium biodiversity in the Flora de Sao Paulo treatment by not providing any new
collection of these species for Sao Paulo state, and this is exemplified by the following new species, which was recently collected in the region of Tapirai and also belongs to the complex of species of N. amazonicum and N. krisgreeniae. —See Leme 2009d p. 59(6): 245-255
