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Global biodiversity assessment and hyper-cryptic species complexes: more than one species of elephant in the room?

Citation

Adams, M and Raadik, TA and Burridge, CP and Georges, A, Global biodiversity assessment and hyper-cryptic species complexes: more than one species of elephant in the room?, Systematic Biology, 63, (4) pp. 518-533. ISSN 1063-5157 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 The Authors

DOI: doi:10.1093/sysbio/syu017

Abstract

Several recent estimates of global biodiversity have concluded that the total number of species on Earth lies near the lower end of the wide range touted in previous decades. However, none of these recent estimates formally explore the real 'elephant in the room', namely, what proportion of species are taxonomically invisible to conventional assessments, and thus, as undiagnosed cryptic species, remain uncountable until revealed by multi-gene molecular assessments. Here we explore the significance and extent of so-called 'hyper-cryptic' species complexes, using the Australian freshwater fish Galaxias olidus as a proxy for any organism whose taxonomy ought to be largely finalized when compared to those in little-studied or morphologically undifferentiated groups. Our comprehensive allozyme (838 fish for 54 putative loci), mtDNA (557 fish for 605bp of cytb), and morphological (1963-3389 vouchers for 17-58 characters) assessment of this species across its broad geographic range revealed a 1500% increase in species-level biodiversity, and suggested that additional taxa may remain undiscovered. Importantly, while all 15 candidate species were morphologically diagnosable a posteriori from one another, single-gene DNA barcoding proved largely unsuccessful as an a priori method for species identification. These results lead us to draw two strong inferences of relevance to estimates of global biodiversity. First, hyper-cryptic complexes are likely to be common in many organismal groups. Second, no assessment of species numbers can be considered 'best practice' in the molecular age unless it explicitly includes estimates of the extent of cryptic and hyper-cryptic biodiversity.

Item Details

Item Type:Refereed Article
Keywords:Galaxiidae, global estimates, hyper-diverse, mountain galaxias, species counts, species richness
Research Division:Biological Sciences
Research Group:Evolutionary Biology
Research Field:Animal Systematics and Taxonomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Environmental Sciences
Author:Burridge, CP (Dr Christopher Burridge)
ID Code:98121
Year Published:2014
Web of Science® Times Cited:35
Deposited By:Zoology
Deposited On:2015-02-02
Last Modified:2017-11-01
Downloads:0

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