Exploring ‘endangered living fossils’ (ELFs) among monotypic genera of plants and animals of the world

Abstract

The recently proposed concept of ´endangered living fossils’ (ELFs) integrates high-endangered status and evolutionary singularity for any species. In this review, I gathered monotypic genera (single-species genera) that satisfy the three ELF criteria: (i) scarcity and narrow distribution of populations, i.e., considering every species categorized ‘critically endangered’ or contemporary ´extinct´ by IUCN criteria; (ii) evolutionary singularity, i.e., both morphological and phylogenetic singularities of a single-species lineage as a result of a null net diversification rate; and (iii) ancient divergence, i.e., split from the closest extant relatives predating a particular geological epoch. A total of 3,706 monotypic genera of vertebrates and angiosperms were analyzed. I found 109 critically endangered and contemporary extinct genera of which 57 were ELFs. The emergent patterns are: (1) taxonomy (generic level) is a reliable first approach to identifying ELFs; (2) ´morphological singularity´ displayed by monotypic genera does not always help identify ELFs on islands; (3) species of monotypic genera tend to be more threatened than average species; (4) extinction appears to be biased against some animal and plant groups; (5) contemporary extinct genera are strongly associated with distribution on islands, particularly for flightless birds vulnerable to human prosecution; and (6) the ELF approach is a relatively quick method to identify the species of floras and faunas most urgently in need of protection in the world. This approach is complementary to any method searching for phylogenetic diversity (e. g. EDGE), which is also discussed. I argue that ELFs should be prioritized in conservation because they are the most threatened lineages representing an exceptional evolutionary heritage in the world.

Fish diversity and selection of taxa for conservation in the Salween and Irrawaddy Rivers, Southeast Asia

“…According to Eschmeyer's catalog of fishes 45 , the distribution of these monotypic genera is very narrow. Vargas 17 suggested the concept of “endangered living fossils” (ELFs), integrating the highly endangered status and evolutionary singularity of any species, and proposed that monotypic genera met three ELF criteria, one of which was scarcity and narrow distribution of the population. The Salween and Irrawaddy River basins have a very high proportion of monotypic genera, with several of these representing unique species and genera endemic to the basins studied (Table 6 ).…”

“…This information is of particular importance when planning and constructing protected areas, as it is necessary to decide which taxa should be selected as key conservation targets. Several studies have been concerned with the classification and conservation significance of monotypic genera (single species genera) in different biological groups 13 – 17 . However, there is to date no report on the selection of monotypic genera as conservation targets for freshwater fish in a river basin.…”

Plant Conservation in the Midst of Energy Transition: Can Regional Governments Rise to the Challenge?

“…Table 1 shows the rankings for each of the evaluated items. Species characterized by significant phylogenetic distinctiveness, such as endangered living fossils (ELFs), or those belonging to monotypic genera [89], had their assigned values tripled as a corrective factor.…”