Evolution in the Notostraca

Longhurst, Alan R.

doi:10.2307/2405360

Cited by 45 publications

(22 citation statements)

References 3 publications

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“…Despite this, the evolutionary history of reproductive systems in Notostraca is unknown due to the lack of a resolved phylogeny [33,34], and the poor knowledge of the diversity of the group, partly due to the widespread presence of cryptic species [32,35-38]. Gonochorism has been hypothesized to be the ancestral state in the group, and the evolution of self-fertile hermaphroditism and AD has been linked to reproductive assurance in the context of range expansions, possibly after glacial retreat [8,31,39,40], although this has never been explicitly tested.…”

Section: Introductionmentioning

confidence: 99%

“…Information on sexual system was compiled and Maximum Parsimony (MP) and model-based Maximum Likelihood (ML) character mapping approaches were used on the phylogeny to investigate sexual system evolution across the order. We also tested the hypothesis that reproductive assurance has driven the evolution of self-fertilisation across Notostraca [8,39]. Taxa found at higher latitudes are likely to have experienced bouts of colonisation during post glacial range expansions, which would select for AD/hermaphroditism.…”

Section: Introductionmentioning

confidence: 99%

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High lability of sexual system over 250 million years of evolution in morphologically conservative tadpole shrimps

et al. 2013

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BackgroundSexual system is a key factor affecting the genetic diversity, population structure, genome structure and the evolutionary potential of species. The sexual system androdioecy – where males and hermaphrodites coexist in populations – is extremely rare, yet is found in three crustacean groups, barnacles, a genus of clam shrimps Eulimnadia, and in the order Notostraca, the tadpole shrimps. In the ancient crustacean order Notostraca, high morphological conservatism contrasts with a wide diversity of sexual systems, including androdioecy. An understanding of the evolution of sexual systems in this group has been hampered by poor phylogenetic resolution and confounded by the widespread occurrence of cryptic species. Here we use a multigene supermatrix for 30 taxa to produce a comprehensive phylogenetic reconstruction of Notostraca. Based on this phylogenetic reconstruction we use character mapping techniques to investigate the evolution of sexual systems. We also tested the hypothesis that reproductive assurance has driven the evolution of androdioecy in Notostraca.ResultsCharacter mapping analysis showed that sexual system is an extremely flexible trait within Notostraca, with repeated shifts between gonochorism and androdioecy, the latter having evolved a minimum of five times. In agreement with the reproductive assurance hypothesis androdioecious notostracans are found at significantly higher latitudes than gonochoric ones indicating that post glacial re-colonisation may have selected for the higher colonisation ability conferred by androdioecy.ConclusionsIn contrast to their conserved morphology, sexual system in Notostraca is highly labile and the rare reproductive mode androdioecy has evolved repeatedly within the order. Furthermore, we conclude that this lability of sexual system has been maintained for at least 250 million years and may have contributed to the long term evolutionary persistence of Notostraca. Our results further our understanding of the evolution of androdioecy and indicate that reproductive assurance is a recurrent theme involved in the evolution of this sexual system.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High lability of sexual system over 250 million years of evolution in morphologically conservative tadpole shrimps

et al. 2013

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“…The fossil record for Triops and Lepidurus, the only two extant genera, extends as far back as the Triassic. Despite the roughly 200 million years which have elapsed since that time, some fossil specimens are so similar to the modern T. cancriformis that they would be considered conspecifics if the fossil forms were alive today (Tasch, 1969;Trusheim, 1938;Longhurst, 1955a). Paradoxically, long-term stability in notostracan gross morphology has been accompanied by hypervariability (i.e., plasticity) in many individual morphological characters (Longhurst, 1958).…”

Section: Introductionmentioning

confidence: 99%

Cryptic Species in a “Living Fossil” Lineage: Taxonomic and Phylogenetic Relationships within the GenusLepidurus(Crustacea: Notostraca) in North America

King

Hanner

1998

Molecular Phylogenetics and Evolution

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“…Some studies use fossil invertebrates to illuminate key concepts like convergence or parallelism (Cloud 1948), and treat the impact of ontogeny on evolutionary trends in terms of heterochrony, including the inference of developmental Leptoplastus & Ctenopyge Genus series across strata. The papers on geographic distribution, population diversity, and speciation include assessments of adaptation and distribution in notostracan crustaceans (Longhurst 1955), balanced polymorphism in marine copepods (Battaglia 1958), geographic variation in acorn worms (Rao 1952), niche diversity and species ranges for sponges (Hartman 1957), and allopatric speciation, variation, and hybridization in echinoids (Vasseur 1952;Swan 1953;Mayr 1954). The most significant feature of these papers on marine invertebrates is what is absent.…”

Section: Model Organism Exclusion In the Modern Synthesis: The Case Omentioning

confidence: 99%

Marine invertebrates, model organisms, and the modern synthesis: epistemic values, evo-devo, and exclusion

Love

2009

Theory Biosci.

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A central reason that undergirds the significance of evo-devo is the claim that development was left out of the Modern synthesis. This claim turns out to be quite complicated, both in terms of whether development was genuinely excluded and how to understand the different kinds of embryological research that might have contributed. The present paper reevaluates this central claim by focusing on the practice of model organism choice. Through a survey of examples utilized in the literature of the Modern synthesis, I identify a previously overlooked feature: exclusion of research on marine invertebrates. Understanding the import of this pattern requires interpreting it in terms of two epistemic values operating in biological research: theoretical generality and explanatory completeness. In tandem, these values clarify and enhance the significance of this exclusion. The absence of marine invertebrates implied both a lack of generality in the resulting theory and a lack of completeness with respect to particular evolutionary problems, such as evolvability and the origin of novelty. These problems were salient to embryological researchers aware of the variation and diversity of larval forms in marine invertebrates. In closing, I apply this analysis to model organism choice in evo-devo and discuss its relevance for an extended evolutionary synthesis.

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Evolution in the Notostraca

Cited by 45 publications

References 3 publications

High lability of sexual system over 250 million years of evolution in morphologically conservative tadpole shrimps

High lability of sexual system over 250 million years of evolution in morphologically conservative tadpole shrimps

Cryptic Species in a “Living Fossil” Lineage: Taxonomic and Phylogenetic Relationships within the GenusLepidurus(Crustacea: Notostraca) in North America

Marine invertebrates, model organisms, and the modern synthesis: epistemic values, evo-devo, and exclusion

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