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The subspecies rank has been widely applied by taxonomists to capture infraspecific variation within the Linnaean classification system. Many subspecies described throughout the 20th century were recognised largely based on perceived variation in single morphological characters yet have since been found not to correspond to separately evolving population lineages, thus requiring synonymy or elevation to full species under lineage-based views of species. These modern lineage-based taxonomic resolutions have resulted from a combination of new molecular genetic techniques, improved geographical sampling of specimens, and more sophisticated analyses of morphological variation (e.g., statistical assessments rather than solely univariate descriptive ones). Here, we revisit the current taxonomic arrangement of species-level and subspecific taxa in the Lerista microtis (Gray) group, which is distributed along a narrow ~2000 km strip on the southern coast of Australia. From specimens of the L. microtis group, an additional species (Lerista arenicola) and two additional subspecies (L. m. intermedia and L. m. schwaneri) were described. We collected data on mensural, meristic, and colour pattern characters to explore morpho-spatial relationships among these taxa. Although our morphological analyses revealed some distinctiveness among specimens from locations assigned to each taxon, this variation is continuous along Australia’s southern coastline, assuming the form of a geographic cline rather than discrete forms. For many characters, however, spatial patterns were inconsistent with the original descriptions, particularly of the subspecies. Moreover, analysis of genome wide restriction-associated DNA loci revealed multiple instances of paraphyly among taxa, with phylogenetic clustering of specimens assigned to distinct species and subspecies. These emerging patterns provide no support for L. arenicola as a species evolving separately from L. microtis. Additionally, our findings challenge the presumed distinctiveness and coherence of the three subspecies of L. microtis. We thus synonymise L. arenicola and the L. microtis subspecies with L. microtis and provide a redescription of a single yet morphologically variable species—an arrangement that best reflects evolutionary history and the continuous nature of morphological variation across space.
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Wither the subspecies?: an ecological perspective on taxonomic, environmental and sexual determinants of phenotypic variation in Big-eared woolly bats, Chrotopterus auritus
Continuous phenotypic variation reflecting geographic clines can be difficult to distinguish from subspecific discontinuities when specimens are few and heterogeneously distributed. Nonetheless, increases in the holdings of museum collections over the last decades contribute to our ability to resolve more fine-scaled phenotypic gradients for many species. Although the Big-eared woolly bat is not commonly encountered and thus poorly represented in museum collections, sufficient numbers have accumulated to allow an assessment of sub-specific, sexual, spatial and environmental components of phenotypic variation. I examined 123 specimens from across the distribution of Chrotopterus auritus and characterized phenotype based on external, cranial and mandibular characteristics and decomposed variation into components based on univariate and multivariate statistical analyses. All components accounted for significant phenotypic variation. Nonetheless, when examined together and after accounting for correlated variation among components, only sexual, spatial and environmental components accounted for significant unique variation. This, combined with the observation that all qualitative characteristics used to define subspecies of C. auritus can be observed throughout its geographic range, suggest that phenotypic variation is clinal and not characterized by discontinuities reflective of subspecies. Clinal variation was most related to temperature and its seasonality highlighting the important role that these climatic characteristics play in many aspects of the biology of Phyllostomidae.
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- Award ID(s):
- 2101909
- PAR ID:
- 10470644
- Publisher / Repository:
- Linnean Society
- Date Published:
- Journal Name:
- Biological Journal of the Linnean Society
- ISSN:
- 0024-4066
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/biolinnean/blad006
