Reproduction and Larval Morphology of Broadcasting and Viviparous Species in the<i>Cryptasterina</i>Species Complex

Byrne, Maria; Hart, Michael W.; Cerra, Anna; Cisternas, Paula

doi:10.2307/1543292

Cited by 54 publications

(32 citation statements)

References 41 publications

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“…If P. mortenseni has planktotrophic larval development like P. regularis, then their distant phylogenetic relationship might increase the measured conflict between nucleotide and life history characters. Our results and other recent studies (O'Loughlin et al 2002;Byrne et al 2003) illustrate the need for an expanded survey of taxonomic and reproductive diversity in asterinids. However, at least for asterinids, it is not clear whether unrecognized species diversity should generally be expected to decrease the observed conflict between nucleotide and early life history characters, or to improve the otherwise weak utility of early life history characters for phylogenetic analysis.…”

Section: Galley 353supporting

confidence: 79%

Strong character incongruence and character choice in phylogeny of sea stars of the Asterinidae

Hart

Johnson

Addison

et al. 2004

Invertebrate Biology

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Abstract. Historically, characters from early animal development have been a potentially rich source of phylogenetic information, but many traits associated with the gametes and larval stages of animals with complex life cycles are widely suspected to have evolved frequent convergent similarities. Such convergences will confound true phylogenetic relationships. We compared phylogenetic inferences based on early life history traits with those from mitochondrial DNA sequences for sea stars in the genera Asterina, Cryptasterina, and Patiriella (Valvatida: Asterinidae). Analysis of these two character sets produced phylogenies that shared few clades. We quantified the degree of homoplasy in each character set when mapped onto the phylogeny inferred from the alternative characters. The incongruence between early life history and nucleotide characters implies more homoplasy in the life history character set. We suggest that the early life history traits in this case are most likely to be misleading as phylogenetic characters because simple adaptive models predict convergence in early life histories. We show that adding early life history characters may slightly improve a phylogeny based on nucleotide sequences, but adding nucleotide characters may be critically important to improving inferences from phylogenies based on early life history characters.Additional key words: total evidence, modes of development, life history, mtDNA, AsteroideaThe choice of characters for use in phylogenetic analyses is an important and contentious issue in animal phylogenetics. Since Haeckel (1866), phenotypic characters from the earliest parts of the life cycle (such as the morphological forms of planktonic larvae) have been viewed as a potentially rich source of phylogenetic information. However, even in the early 20 th century, there was growing skepticism of the utility of early life history characters for tracing evolutionary relationships (e.g., Conklin 1928; Gould 1977). The subsequent growth of larval ecology as a research discipline led to renewed interest in the phylogenetic history of embryological and larval diversity, with a sharp focus on the study of early life history characters expressed during sexual reproduction or during larval development before metamorphosis to the adult form (McHugh & Rouse 1998). Molecular phylogenetic studies of taxa that include species with diverse early a Author for correspondence. E-mail: michael.hart@dal.ca b Present address: Department of Biological Sciences, SimonFraser University, Burnaby, British Columbia V5A 1S6, Canada life histories have suggested the evolution of convergent similarities in early life history characters such as egg size, type of parental care, offspring dispersal ability, larval morphology, and fertilization ecology (Hart 2000). Many of these characters reflect functional adaptations of a complex life cycle in which individuals sequentially inhabit planktonic and benthic habitats: the similarities in character states could represent shared ancestral states as a result ...

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Section: Galley 353supporting

confidence: 79%

Strong character incongruence and character choice in phylogeny of sea stars of the Asterinidae

Hart

Johnson

Addison

et al. 2004

Invertebrate Biology

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“…This latitudinal difference mirrors the geography of live-bearing in other asterinid lineages, in which viviparous species (especially Cryptasterina pacifica, Parvulastra vivipara, Asterina phylactica) have short geographical ranges at high latitudes on the margin of the distributions of their nonviviparous sister taxa in the same genera [24,25,30,31]. Our phylogeographic analyses were designed to investigate the history of this geographical distribution and its potential role in the phenotypic and reproductive divergence of the two species.…”

Section: Introductionmentioning

confidence: 80%

Extraordinarily rapid life-history divergence between Cryptasterina sea star species

et al. 2012

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Life history plays a critical role in governing microevolutionary processes such as gene flow and adaptation, as well as macroevolutionary processes such speciation. Here, we use multilocus phylogeographic analyses to examine a speciation event involving spectacular life-history differences between sister species of sea stars. Cryptasterina hystera has evolved a suite of derived life-history traits (including internal self-fertilization and brood protection) that differ from its sister species Cryptasterina pentagona, a gonochoric broadcast spawner. We show that these species have only been reproductively isolated for approximately 6000 years (95% highest posterior density of 905-22 628), and that this life-history change may be responsible for dramatic genetic consequences, including low nucleotide diversity, zero heterozygosity and no gene flow. The rapid divergence of these species rules out some mechanisms of isolation such as adaptation to microhabitats in sympatry, or slow divergence by genetic drift during prolonged isolation. We hypothesize that the large phenotypic differences between species relative to the short divergence time suggests that the lifehistory differences observed may be direct responses to disruptive selection between populations. We speculate that local environmental or demographic differences at the southern range margin are possible mechanisms of selection driving one of the fastest known marine speciation events.

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“…This association of sexuality and reproductive mode has been suggested for several animal groups (e.g. scleractinian corals: [11]; alcyonacean anthozoans: [5]; unionioid bivalves: [42]; asterinid asteroids: [43]), but its rate and direction of change have not previously been determined.…”

Section: Discussion (A) Ancestral-state Reconstructionmentioning

confidence: 73%

Correlated evolution of sex and reproductive mode in corals (Anthozoa: Scleractinia)

2010

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Sexuality and reproductive mode are two fundamental life-history traits that exhibit largely unexplained macroevolutionary patterns among the major groups of multicellular organisms. For example, the cnidarian class Anthozoa (corals and anemones) is mainly comprised of gonochoric (separate sex) brooders or spawners, while one order, Scleractinia (skeleton-forming corals), appears to be mostly hermaphroditic spawners. Here, using the most complete phylogeny of scleractinians, we reconstruct how evolutionary transitions between sexual systems (gonochorism versus hermaphrodism) and reproductive modes (brooding versus spawning) have generated large-scale taxonomic patterns in these characters. Hermaphrodites have independently evolved in three large, distantly related lineages consisting of mostly reef-building species. Reproductive mode in corals has evolved at twice the rate of sexuality, while the evolution of sexuality has been heavily biased: gonochorism is over 100 times more likely to be lost than gained, and can only be acquired by brooders. This circuitous evolutionary pathway accounts for the prevalence of hermaphroditic spawners among reef-forming scleractinians, despite their ancient gonochoric heritage.

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Reproduction and Larval Morphology of Broadcasting and Viviparous Species in theCryptasterinaSpecies Complex

Cited by 54 publications

References 41 publications

Strong character incongruence and character choice in phylogeny of sea stars of the Asterinidae

Strong character incongruence and character choice in phylogeny of sea stars of the Asterinidae

Extraordinarily rapid life-history divergence between Cryptasterina sea star species

Correlated evolution of sex and reproductive mode in corals (Anthozoa: Scleractinia)

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