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Theory predicts that sexually dimorphic traits under strong sexual selection, particularly those involved with intersexual signaling, can accelerate speciation and produce bursts of diversification. Sexual dichromatism (sexual dimorphism in color) is widely used as a proxy for sexual selection and is associated with rapid diversification in several animal groups, yet studies using phylogenetic comparative methods to explicitly test for an association between sexual dichromatism and diversification have produced conflicting results. Sexual dichromatism is rare in frogs, but it is both striking and prevalent in African reed frogs, a major component of the diverse frog radiation termed Afrobatrachia. In contrast to most other vertebrates, reed frogs display female-biased dichromatism in which females undergo color transformation, often resulting in more ornate coloration in females than in males. We produce a robust phylogeny of Afrobatrachia to investigate the evolutionary origins of sexual dichromatism in this radiation and examine whether the presence of dichromatism is associated with increased rates of net diversification. We find that sexual dichromatism evolved once within hyperoliids and was followed by numerous independent reversals to monochromatism. We detect significant diversification rate heterogeneity in Afrobatrachia and find that sexually dichromatic lineages have double the average net diversification rate of monochromatic lineages. By conducting trait simulations on our empirical phylogeny, we demonstrate that our inference of trait-dependent diversification is robust. Although sexual dichromatism in hyperoliid frogs is linked to their rapid diversification and supports macroevolutionary predictions of speciation by sexual selection, the function of dichromatism in reed frogs remains unclear. We propose that reed frogs are a compelling system for studying the roles of natural and sexual selection on the evolution of sexual dichromatism across micro- and macroevolutionary timescales., (© The Author(s) 2019. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Organismal traits interact with environmental variation to mediate how species respond to shared landscapes. Thus, differences in traits related to dispersal ability or physiological tolerance may result in phylogeographic discordance among co-distributed taxa, even when they are responding to common barriers. We quantified climatic suitability and stability, and phylogeographic divergence within three reed frog species complexes across the Guineo-Congolian forests and Gulf of Guinea archipelago of Central Africa to investigate how they responded to a shared climatic and geological history. Our species-specific estimates of climatic suitability through time are consistent with temporal and spatial heterogeneity in diversification among the species complexes, indicating that differences in ecological breadth may partly explain these idiosyncratic patterns. Likewise, we demonstrated that fluctuating sea levels periodically exposed a land bridge connecting Bioko Island with the mainland Guineo-Congolian forest and that habitats across the exposed land bridge likely enabled dispersal in some species, but not in others. We did not find evidence that rivers are biogeographic barriers across any of the species complexes. Despite marked differences in the geographic extent of stable climates and temporal estimates of divergence among the species complexes, we recovered a shared pattern of intermittent climatic suitability with recent population connectivity and demographic expansion across the Congo Basin. This pattern supports the hypothesis that genetic exchange across the Congo Basin during humid periods, followed by vicariance during arid periods, has shaped regional diversity. Finally, we identified many distinct lineages among our focal taxa, some of which may reflect incipient or unrecognized species., (© 2017 John Wiley & Sons Ltd.)

The niche-filling process predicted by the "ecological opportunity" (EO) model is an often-invoked mechanism for generating exceptional diversity in island colonizers. Whether the same process governs lineage accumulation and trait disparity during continental colonization events is less clear. Here, we test this prediction by investigating the rate dynamics and trait evolution of one of Africa's most widespread amphibian colonizers, the true toads (Bufonidae). By reconstructing the most complete molecular phylogeny of African Bufonidae to date, we find that the diversification of lineages in Africa best conforms to a constant rate model throughout time and across subclades, with little support for EO. Evolutionary rates of life-history traits have similarly been constant over time. However, an analysis of generalists and specialists showed a shift toward higher speciation rates associated with habitat specialization. The overall lack of EO signal can be interpreted in a number of ways and we propose several explanations. Firstly, methodological issues might preclude the detection of EO. Secondly, colonizers might not experience true EO conditions and due to the size, ecological heterogeneity and age of landmasses, the diversification processes might be more complex. Thirdly, lower speciation rates of habitat generalists may have affected overall proliferation of lineages., (© 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.)

The phylogenetic relationships of the African mongrel frog genus Nothophryne are poorly understood. We provide the first molecular assessment of the phylogenetic position of, and diversity within, this monotypic genus from across its range-the Afromontane regions of Malawi and Mozambique. Our analysis using a two-tiered phylogenetic approach allowed us to place the genus in Pyxicephalidae. Within the family, Nothophryne grouped with Tomopterna, a hypothesis judged significantly better than alternative hypotheses proposed based on morphology. Our analyses of populations across the range of Nothophryne suggest the presence of several cryptic species, at least one species per mountain. Formal recognition of these species is pending but there is a major conservation concern for these narrowly distributed populations in an area impacted by major habitat change. The phylogenetic tree of pyxicephalids is used to examine evolution of life history, ancestral habitat, and biogeography of this group., (Copyright © 2016 Elsevier Inc. All rights reserved.)

We examined specimens from all eleven described species of African Dainty Frogs, Cacosternum. Advertisement calls, 16S and tyr sequences were obtained from voucher specimens of all known species plus undescribed taxa. A phylogenetic analysis indicated that there were 15 species. We describe four new species from South Africa that can be diagnosed by their advertisement calls: Cacosternum aggestum sp. nov. from the interior of the south-western Cape, the large C. nanogularum sp. nov. from KwaZulu-Natal, C. australis sp. nov. from the Western Cape Province and C. rhythmum sp. nov. from the KwaZulu-Natal midlands. Cacosternum schebeni is confirmed as ajunior synonym of C. boettgeri, and we agree that C. poyntoni is a junior synonym of C. nanum. The populations of dainty frogs on the Ethiopian highlands remain to be investigated. Shared tyr haplotypes occur between species that are not necessarily closely related, but always sympatric, at least in the recent past. This is evidence for hybridisation that requires further investigation. A provisional identification key to the species is provided.

Premise of the Study: Dated molecular phylogenies suggest a Cenozoic origin for the crown group of Equisetum. but compression fossil equisetaleans that are morphologically indistinguishable from extant Equisetum and recently discovered anatomically preserved examples strongly suggest an earlier Mesozoic initial diversification., Methods: In situ samples of Equisetum thermale sp. nov. from the Upper Jurassic San Agustín hot spring deposit were collected and studied with the use of polished blocks, thin sections, and light microscopy., Key Results: Equisetum thermale exhibits all the morphological and anatomical characteristics of the extant crown group Equisetum. It shows a mixture of features present in the two extant subgenera, e.g., superficial stomata typical of subgenus Equisetum allied with infrequently ramifying stems typical of subgenus Hippochaete. This appears to ally E. thermale with the least derived extant species in the genus Equisetum bogotense (sister species to the two subgenera). Its association of hydromorphic and xeromorphic characters allowed it to grow as an emergent aquatic in physically and chemically stressed geothermally influenced wetlands, where it formed dense monospecific stands. Equisetum thermale, because it is preserved in situ with intact anatomy, provides clear paleoecological, biological, plus inferred paleoecophysiological evidence of adaptations known in extant species., Conclusions: As the earliest unequivocal member of the genus, E. thermale supports the hypothesis of a Mesozoic origin. Its inferred tolerance of a similar range of stresses (e.g., high salinity, alkalinity, and heavy metal concentrations) to that seen in extant Equisetum suggests early evolution and subsequent maintenance of ecophysiological innovations in the genus.

Frogs of the genus Tomopterna occur throughout sub-Saharan Africa. Previous work has shown that there are seven cryptic species, which occupy diverse habitats from grasslands to deserts. The current paper proposes a phylogeny of Tomopterna based on partial sequences of the mitochondrial 12S rRNA gene. A gene tree for the genus, including all seven named species and three undescribed species which were discovered during the course of this study, is presented., ((C)2002 Elsevier Science (USA).)

A comprehensive survey of the Cape Fold Mountains, South Africa, was undertaken for moss frogs of the genusArthroleptella. Advertisement calls were recorded and voucher specimens collected for all populations encountered. A molecular phylogeny was constructed for the entire genus using two mitochondrial and one nuclear marker. Standard morphological measurements were made and salient morphological characters described. Analysis of these data revealed the presence of three undescribed species: two that were previously obscured underArthroleptella bicolorand one obscured underA. landdrosiaare described herein. The advertisement calls of the three new species are described and contrasted with the calls of otherArthroleptellaspecies. Their distribution is described and spatial extent of occurrence quantified along with a brief discussion of conservation status for each species. ZooBank.—Arthroleptella draconella: urn:lsid:zoobank.org:act:341BABC2-63A8-4C60-A306-D232E92ECE69 Arthroleptella atermina: urn:lsid:zoobank.org:act:AC23D804-3075-40DB-9852-624C32A51547 Arthroleptella kogelbergensis: urn:lsid:zoobank.org:act:AA573B06-BA81-4B84-B436-5F5CCDF1D892. [ABSTRACT FROM AUTHOR]

DNA sequence data from a 296 base pair variable region of the plastid encoded rbcL gene was obtained from 19th century type material of Spongites decipiens and of Lithophyllum tumidum (=Pseudolithophyllum neofarlowii) and matched to field-collected material, confirming the application of these specific epithets in the northeast Pacific. Phylogenetic analyses of separate and concatenated rbcL and psbA gene sequences show that both species belong in Spongites. Based on DNA sequences, the distribution of S. decipiens is confirmed from Haida Gwaii, British Columbia, Canada, south to its type locality at San Pedro, Los Angeles County, California, whereas, Spongites tumidum is distributed from near Sitka, Alaska, to Monterey County, California. Sequence data from S. decipiens and South African specimens called Spongites yendoi confirm anatomical studies that these two species are distinct but that a previously undescribed, cryptic species, Spongites agulhensis, also is present in South Africa. Anatomically and morphologically S. agulhensis is very similar to both northeast Pacific 5. decipiens and South African 5. yendoi, differing from the former by a single anatomical character and from the latter by two anatomical characters. Anatomy, ecology and distributions are useful in separating the South African species of Spongites, as well as the northeast Pacific species. Sequence divergence values align with biogeographic patterns and not with anatomical similarities for these Spongites species. We question the practice of placing into synonymy geographically widely separated non-geniculate coralline algal species based solely on anatomical features that likely have resulted from convergent evolution. [ABSTRACT FROM AUTHOR]

Wiens (2007 , Q. Rev. Biol. 82, 55–56) recently published a severe critique of Frost et al.'s (2006, Bull. Am. Mus. Nat. Hist. 297, 1–370) monographic study of amphibian systematics, concluding that it is “a disaster” and recommending that readers “simply ignore this study”. Beyond the hyperbole, Wiens raised four general objections that he regarded as “fatal flaws”: (1) the sampling design was insufficient for the generic changes made and taxonomic changes were made without including all type species; (2) the nuclear gene most commonly used in amphibian phylogenetics, RAG-1, was not included, nor were the morphological characters that had justified the older taxonomy; (3) the analytical method employed is questionable because equally weighted parsimony “assumes that all characters are evolving at equal rates”; and (4) the results were at times “clearly erroneous”, as evidenced by the inferred non-monophyly of marsupial frogs. In this paper we respond to these criticisms. In brief: (1) the study of Frost et al. did not exist in a vacuum and we discussed our evidence and evidence previously obtained by others that documented the non-monophyletic taxa that we corrected. [ABSTRACT FROM AUTHOR]

The Mascarene ridged frog, Ptychadena mascareniensis, is the only African amphibian species thought to occur on Madagascar and on the Seychelles and also Mascarene islands. We explored its phylogenetic relationships and intraspecific genetic differentiation to contribute to the understanding of transoceanic dispersal in amphibians. Fragments of the mitochondrial 16S rRNA gene were sequenced from specimens collected over most of the distribution area of P. mascareniensis, including populations from Madagascar, Mascarenes and Seychelles. We identified five deeply divergent clades having pairwise divergences >5%, which probably all represent cryptic species in a P. mascareniensis complex. One of these seems to be restricted to Madagascar, the Mascarenes and the Seychelles. Sequences obtained from topotypic material (Réunion) were identical to the most widespread haplotype from Madagascar. The single Mauritian/Seychellean haplotype differed by only one mutation from a Malagasy haplotype. It is likely that the Mascarene and Seychellean populations were introduced from Madagascar by humans. In contrast, the absence of the Malagasy haplotypes from Africa and the distinct divergences among Malagasy populations (16 mutations in one divergent hapolotype from northern Madagascar) suggest that Madagascar was populated by Ptychadena before the arrival of humans c. 2000 years ago. Because Madagascar has been separated from Africa since the Jurassic, this colonization must have taken place by overseas rafting, which may be a more widespread dispersal mode in amphibians than commonly thought. [ABSTRACT FROM AUTHOR]

The article discusses the unusual pattern of evolution of the moss frogs, under the genus Arthroleptella, which complicates the species' conservation management. The species general pattern of allopatry, spatial arrangement of genetic distribution and restricted gene flow are briefly described. However, it cites that the distribution and phylogenetic information it has retrieved from the study can be used in the identification of species and area of conservation priority.

The Mascarene ridged frog, Ptychadena mascareniensis , is a species complex that includes numerous lineages occurring mostly in humid savannas and open forests of mainland Africa, Madagascar, the Seychelles, and the Mascarene Islands. Sampling across this broad distribution presents an opportunity to examine the genetic differentiation within this complex and to investigate how the evolution of bioclimatic niches may have shaped current biogeographic patterns. Using model-based phylogenetic methods and molecular-clock dating, we constructed a time-calibrated molecular phylogenetic hypothesis for the group based on mitochondrial 16S rRNA and cytochrome b ( cytb ) genes and the nuclear RAG1 gene from 173 individuals. Haplotype networks were reconstructed and species boundaries were investigated using three species-delimitation approaches: Bayesian generalized mixed Yule-coalescent model (bGMYC), the Poisson Tree Process model (PTP) and a cluster algorithm (SpeciesIdentifier). Estimates of similarity in bioclimatic niche were calculated from species-distribution models ( maxent ) and multivariate statistics (Principal Component Analysis, Discriminant Function Analysis). Ancestral-area reconstructions were performed on the phylogeny using probabilistic approaches implemented in BioGeoBEARS. We detected high levels of genetic differentiation yielding ten distinct lineages or operational taxonomic units, and Central Africa was found to be a diversity hotspot for these frogs. Most speciation events took place throughout the Miocene, including “out-of-Africa” overseas dispersal events to Madagascar in the East and to São Tomé in the West. Bioclimatic niche was remarkably well conserved, with most species tolerating similar temperature and rainfall conditions common to the Central African region. The P. mascareniensis complex provides insights into how bioclimatic niche shaped the current biogeographic patterns with niche conservatism being exhibited by the Central African radiation and niche divergence shaping populations in West Africa and Madagascar. Central Africa, including the Albertine Rift region, has been an important center of diversification for this species complex. [ABSTRACT FROM AUTHOR]