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Abstract The use of species as a concept is an important metric for assessing biological diversity and ecosystem function. However, delimiting species based on morphological characters can be difficult, especially in aquatic plants that exhibit high levels of variation and overlap. The Sphagnum cuspidatum complex, which includes plants that dominate peatland hollows, provides an example of challenges in species delimitation. Microscopic characters that have been used to define taxa and the possibility that these characters may simply be phenoplastic responses to variation in water availability make species delimitation in this group especially difficult. In particular, the use of leaf shape and serration, which have been used to separate species in the complex, have resulted in divergent taxonomic treatments. Using a combination of high-resolution population genomic data (RADseq) and a robust morphological assessment of plants representing the focal species, we provide evidence to evaluate putative species in this complex. Our data support the recognition of S. cuspidatum, S. fitzgeraldii, S. mississippiense, and S. trinitense as genetically distinct species that can be separated morphologically. These results indicate that S. viride does not differ genetically from S. cuspidatum. Our results are broadly relevant to other aquatic groups where leaf shape and marginal teeth are used to distinguish species.
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Integrative Systematics Reveals Cryptic Diversity in Paraphrynus Whip Spiders (Amblypygi: Phrynidae) from Southwestern North America
Due to their continuous growth, reclusive nature, and low vagility, the distributions and species limits of many whip spiders (Amblypygi Thorell, 1883) remain poorly understood, and much cryptic diversity remains unrecognized. Past attempts to separate the historical “forms” of Paraphrynus Moreno, 1940 into morphologically diagnosable species resulted, for example, in the division of Paraphrynus mexicanus (Bilimek, 1867) into three species—the nominotypical form, Paraphrynus cubensis Quintero, 1983, and Paraphrynus carolynae Armas, 2012. Nevertheless, the limitations of conservative morphology continue to hinder progress towards clarifying the diversity of Paraphrynus. One such example concerns P. carolynae, distributed from Arizona to central Mexico as currently defined. Through the acquisition of new, freshly collected material, the discovery of novel morphological characters, and molecular systematics analyses, it became apparent that P. carolynae comprises at least two morphologically diagnosable species. In this present contribution, the northernmost population of P. carolynae occurring in Arizona and California is described as a new species, Paraphrynus tokdod, sp. nov., raising the number of species in the genus to 22. This investigation also revealed more variation than expected in the secondary spine counts of the pedipalps and the trichobothrial counts of leg IV, previously used for species delimitation in Paraphrynus, suggesting that such characters should be used with caution.
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- PAR ID:
- 10614401
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Diversity
- Volume:
- 16
- Issue:
- 11
- ISSN:
- 1424-2818
- Page Range / eLocation ID:
- 669
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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