scholarly journals Taxonomic Uncertainty and the Anomaly Zone: Phylogenomics Disentangle a Rapid Radiation to Resolve Contentious Species (Gila robusta complex) in the Colorado River

2021 ◽  
Author(s):  
Tyler K Chafin ◽  
Marlis R Douglas ◽  
Max R Bangs ◽  
Bradley T Martin ◽  
Steven M Mussmann ◽  
...  
Keyword(s):  
Colorado River ◽  
Hybrid Origin ◽  
Nominal Species ◽  
Rapid Radiation ◽  
Evolutionary Mechanisms ◽  
Phylogenetic Discordance ◽  
The Status ◽  
Taxonomic Uncertainty ◽  
Morphological Differences ◽  
Phylogenetic Models

Abstract Species are indisputable units for biodiversity conservation, yet their delimitation is fraught with both conceptual and methodological difficulties. A classic example is the taxonomic controversy surrounding the Gila robusta complex in the lower Colorado River of southwestern North America. Nominal species designations were originally defined according to weakly diagnostic morphological differences, but these conflicted with subsequent genetic analyses. Given this ambiguity, the complex was re-defined as a single polytypic unit, with the proposed ‘threatened’ status under the U.S. Endangered Species Act of two elements being withdrawn. Here we re-evaluated the status of the complex by utilizing dense spatial and genomic sampling (N = 387 and >22k loci), coupled with SNP-based coalescent and polymorphism-aware phylogenetic models. In doing so, we found that all three species were indeed supported as evolutionarily independent lineages, despite widespread phylogenetic discordance. To juxtapose this discrepancy with previous studies, we first categorized those evolutionary mechanisms driving discordance, then tested (and subsequently rejected) prior hypotheses which argued phylogenetic discord in the complex was driven by the hybrid origin of Gila nigra. The inconsistent patterns of diversity we found within G. robusta were instead associated with rapid Plio-Pleistocene drainage evolution, with subsequent divergence within the ‘anomaly zone’ of tree space producing ambiguities that served to confound prior studies. Our results not only support resurrection of the three species as distinct entities, but also offer an empirical example of how phylogenetic discordance can be categorized within other recalcitrant taxa, particularly when variation is primarily partitioned at the species-level.

scholarly journals Taxonomic Uncertainty and the Anomaly Zone: Phylogenomics Disentangle a Rapid Radiation to Resolve Contentious Species (Gila robusta complex) in the Colorado River

2019 ◽  
Author(s):  
Tyler K. Chafin ◽  
Marlis R. Douglas ◽  
Max R. Bangs ◽  
Bradley T. Martin ◽  
Steven M. Mussmann ◽  
...  
Keyword(s):  
Colorado River ◽  
Nominal Species ◽  
Rapid Radiation ◽  
Evolutionary Mechanisms ◽  
Phylogenetic Discordance ◽  
The Status ◽  
Taxonomic Uncertainty ◽  
Morphological Differences ◽  
Phylogenetic Models ◽  
Methodological Difficulties

AbstractSpecies is an indisputable unit for biodiversity conservation, yet their delimitation is fraught with both conceptual and methodological difficulties. A classic example is the taxonomic controversy surrounding the Gila robusta complex in the lower Colorado River of southwestern North America. Nominal species designations were originally defined according to weakly diagnostic morphological differences that conflicted with traditional genetic analyses. Consequently, the complex was re-defined as a single polytypic unit, with the proposed ‘threatened’ status of two being withdrawn at the federal level. Here, we utilized dense spatial and genomic sampling (N=387 and >22k loci) to re-evaluate the status of the complex, based on SNP-based coalescent and polymorphism-aware phylogenetic models. In doing so, all three species were supported as evolutionarily independent lineages, despite widespread phylogenetic discordance. To understand this discrepancy with past studies, we categorized evolutionary mechanisms driving discordance. We tested (and subsequently rejected) prior hypotheses suggesting that phylogenetic discord in the complex was hybridization-driven. Instead, we found the G. robusta complex to have diverged within the ‘anomaly zone’ of tree space and, as such, have accumulated inconsistent patterns of diversity which have confounded prior studies. After extending these analyses with phylogeographic modeling, we propose that this is reflective of a rapid radiation promoted by Plio-Pleistocene tectonism. Our results not only support resurrection of the three species as distinct entities, but also offer an empirical example of how phylogenetic discordance can be categorized in other recalcitrant taxa where variation is primarily partitioned at the species-level.

A new riparian Mantidactylus (Brygoomantis) frog from the Tsaratanana and Manongarivo Massifs in northern Madagascar

Zootaxa ◽  
2018 ◽  
Vol 4486 (4) ◽  
pp. 575 ◽  
Author(s):  
MIGUEL VENCES ◽  
ANDREA HILDENBRAND ◽  
KATHARINA M. WARMUTH ◽  
FRANCO ANDREONE ◽  
FRANK GLAW
Keyword(s):  
New Species ◽  
Nuclear Dna ◽  
Taxonomic Revision ◽  
Morphological Characters ◽  
Molecular Data ◽  
Test Case ◽  
Nominal Species ◽  
Type Specimens ◽  
The Status ◽  
Morphological Differences

The subgenus Brygoomantis in the Madagascar-endemic genus Mantidactylus contains 12 nominal species but is in urgent need of taxonomic revision as many additional, genetically divergent but undescribed candidate species have been identified. We here take a first step towards a better resolution of this group by describing a new species, Mantidactylus schulzi sp. nov., occurring at the Tsaratanana and Manongarivo Massifs, differentiated in genetic, bioacoustic and sometimes morphological characters from its closest relatives. We show that upon detailed study, most species in Brygoomantis can be delimited by concordant differentiation of mitochondrial and nuclear DNA, and by bioacoustic and morphological differences. We flag this group of morphologically similar frogs as a test case where molecular data on historical type specimens by ancient DNA methods might be needed to reach a satisfying clarification of taxonomy and nomenclature. However, the status of the new species M. schulzi is not in doubt as it is morphologically distinct from most historical type specimens, and microendemic to a region in northern Madagascar from where no earlier names exist. 

Revision of Mesothymbris Evans, 1956, from the Late Triassic of Mount Crosby, Queensland (Hemiptera: Cicadomorpha: Hylicelloidea: Hylicellidae)

Zootaxa ◽  
2019 ◽  
Vol 4629 (3) ◽  
pp. 389-396
Author(s):  
KEVIN J. LAMBKIN
Keyword(s):  
Basal Cell ◽  
The Other ◽  
Late Triassic ◽  
Nominal Species ◽  
South Eastern ◽  
Incertae Sedis ◽  
Generic Composition ◽  
The Status

New specimens and a re-examination of their holotypes have clarified the status of five species of the extinct cicadomorphan family Hylicellidae from the Late Triassic (Norian) Mount Crosby Formation of south-eastern Queensland. All were found to be conspecific, resulting in the following synonymies: Mesothymbris Evans, 1956 (= Triassoscytina Evans, 1956, syn. nov. = (in part) Triassoscytinopsis Evans, 1956, syn. nov.), Mesothymbris perkinsi Evans, 1956 (= Mesothymbris woodwardi Evans, 1956, syn. nov. = Triassoscytina incompleta Evans, 1956, syn. nov. = Triassoscytinopsis stenulata Evans, 1956, syn. nov. = Triassoscytinopsis aberrans Evans, 1956, syn. nov.). The Hylicellidae is still poorly defined as is its generic composition. Mesothymbris, however, is clearly distinct from the other Mount Crosby hylicellids, Hylicella Evans, 1956, and Triassocotis, Evans, 1956, in the quite distal primary fork of R, the angled RA at the point of separation of RA1 with RA2 directed towards the apex of the tegmen, the upright RA1, the shape of the intra-medial cell, and CuA just distal to the basal cell strongly curved and very closely approximating the claval suture. The new synonymies further clarify the composition of the cicadomorphan fauna of the Mount Crosby Formation, which as a result of this and other recent revisions, now comprises 16 nominal species in the Dysmorphoptilidae, Hylicellidae and Mesojabloniidae, as well as three species incertae sedis. In the presence of Dysmorphoptilidae and Hylicellidae, the Mount Crosby cicadomorphan fauna is similar to that of the younger Late Triassic Blackstone Formation at nearby Denmark Hill and Dinmore. It differs significantly, however, in the absence, after 90 years of collecting of 100s of specimens, of any representatives of the Dunstaniidae, Mesogereonidae, or Tettigarctidae, families so characteristic of the Denmark Hill/Dinmore fauna. Whether this difference is biogeographical, ecological, or simply as a result of differential preservation is unknown. 

scholarly journals Patterns of hybridization and cryptic introgression among one- and four-needled pinyon pines

2020 ◽  
Vol 126 (3) ◽  
pp. 401-411
Author(s):  
Ryan Buck ◽  
Sandra Hyasat ◽  
Alice Hossfeld ◽  
Lluvia Flores-Rentería
Keyword(s):  
Distinct Species ◽  
Hybrid Origin ◽  
Interspecific Mating ◽  
Nucleotide Polymorphisms ◽  
Intermediate Morphology ◽  
The Status ◽  
Number Variation ◽  
Genetic Clusters ◽  
Variable Morphology ◽  
Genetic Contributions

Abstract Background and Aims Pinyon pine hybridization is widely acknowledged, but the frequency of and contributors to such interspecific mating remain largely unstudied. Pinus quadrifolia has three to four needles per fascicle, suggesting that it is a result of hybridization between the five-needled P. juarezensis and the single-needled P. monophylla. In this study we address the taxonomic validity of P. juarezensis, the hybrid origin of P. quadrifolia and the presence of hybridization and intermediate morphology as a result of interspecific hybridization in this complex. Methods We address these questions by combining a genomic and morphological approach. We generated 1868 single nucleotide polymorphisms (SNPs) to detect genetic clusters using principal co-ordinates analyis, discriminant analysis of principal components, fastSTRUCTURE and ADMIXTURE analyses, and performed a morphological analysis of the leaves. Key Results We found that the five-needled pinyons did not differ genetically from the four-needled P. quadrifolia, reducing the status of P. juarezensis to P. quadrifolia. We also found no evidence that P. quadrifolia is of hybrid origin from P. juarezensis × P. monophylla but is instead a genetically distinct species with natural needle number variation that has yet to be explained. Hybridization does occur in this complex, but mostly between P. quadrifolia and P. californiarum, and less commonly between P. quadrifolia and P. monophylla. Interestingly, some hybrid derivatives were detected between both single-needled taxa, P. monophylla and P. californiarum, a hybrid combination that has not yet been proposed. Hybrids have intermediate morphology when they have similar genetic contributions from both parental species; however, when one parent contributes more, hybrid derivatives resemble the parent with higher genetic contribution, resulting in cryptic introgression. Conclusions Our detailed sampling across the distribution of this complex allows us to describe the patterns of hybridization among these taxa, resolves an ancient taxonomic conflict and provides insights into the challenges of exclusively using morphological traits when identifying these taxa with cryptic hybridization and variable morphology.

Cardiofilaria pavlovskyi Strom, 1937 and Avioserpens sp. (Nematoda) from Canadian ciconiiform birds

1973 ◽  
Vol 51 (8) ◽  
pp. 847-851 ◽  
Author(s):  
George G. Gibson
Keyword(s):  
New Brunswick ◽  
Nominal Species ◽  
Immature Female ◽  
New Host ◽  
Ardea Herodias ◽  
The Status ◽  
Ixobrychus Exilis ◽  
Botaurus Lentiginosus

Cardiofilaria ardae (Mawson, 1957) is considered to be a synonym of Cardiofilaria pavlovskyi Strom, 1937, specimens of which were found in Ardea herodias from New Brunswick and in a new host, Ixobrychus exilis, from Ontario. Male and immature female Avioserpens sp. are reported from Botaurus lentiginosus, Quebec, and immature females from I. exilis, Ontario. The males have six to seven caudal papillae per side and have spicules that resemble those of A. mosgovoyi Supryaga, 1965 but are nearly twice as long. The status of the seven nominal species of Avioserpens is discussed briefly.

A first step towards the revision of Cicurina: redescription of type specimens of 60 troglobitic species of the subgenus Cicurella (Araneae: Dictynidae), and a first visual assessment of their distribution

Zootaxa ◽  
2009 ◽  
Vol 2002 (1) ◽  
pp. 1-67 ◽  
Author(s):  
PIERRE PAQUIN ◽  
NADINE DUPÉRRÉ
Keyword(s):  
Conservation Status ◽  
Intraspecific Variability ◽  
Taxonomic Revision ◽  
Visual Assessment ◽  
Nominal Species ◽  
Type Specimens ◽  
Numerous Species ◽  
Morphological Differences ◽  
The U.S ◽  
Conservation And Management

The intraspecific variability recently documented in the genus Cicurina strongly suggests a reassessment of the taxonomy, particularly for the troglobitic members. Adult troglobitic Cicurina (subgenus Cicurella) are rare and most of the 60 nominal species of troglobitic Cicurina (Cicurella) were originally described upon the examination of only one or two females, resulting in numerous species differing only in minor variations of the female genitalia. In many cases, such morphological differences could also be interpreted as intraspecific variability. We present the first step of the taxonomic revision of the genus with the redescription of all troglobitic species of the subgenus Cicurella based on type specimens to provide a reliable and comparable morphological basis: Cicurina bandera Gertsch 1992, C. bandida Gertsch 1992, C. baronia Gertsch 1992, C. barri Gertsch 1992, C. browni Gertsch 1992, C. brunsi Cokendolpher 2004, C. bullis Cokendolpher 2004, C. buwata Chamberlin & Ivie 1940, C. caliga Cokendolpher & Reddell 2001, C. caverna Gertsch 1992, C. coahuila Gertsch 1971, C. coryelli Gertsch 1992, C. cueva Gertsch 1992, C. delrio Gertsch 1992, C. ezelliGertsch 1992, C. gruta Gertsch 1992, C. holsingeri Gertsch 1992, C. hoodensis Cokendolpher & Reddell 2001, C. leona Gertsch 1992, C. loftini Cokendolpher 2004, C. machete Gertsch 1992, C. madla Gertsch 1992, C. maya Gertsch 1977, C. mckenziei Gertsch 1992, C. medina Gertsch 1992, C. menardia Gertsch 1992, C. mirifica Gertsch 1992, C. mixmaster Cokendolpher & Reddell 2001, C. neovespera Cokendolpher 2004, C. obscura Gertsch 1992, C. orellia Gertsch 1992, C. pablo Gertsch 1992, C. pastura Gertsch 1992, C. patei Gertsch 1992, C. platypus Cokendolpher 2004, C. porteri Gertsch 1992, C. puentecilla Gertsch 1992, C. rainesi Gertsch 1992, C. reclusa Gertsch 1992, C. reddelli Gertsch 1992, C. reyesi Gertsch 1992, C. russelli Gertsch 1992, C. sansaba Gertsch 1992, C. selecta Gertsch 1992, C. serena Gertsch 1992, C. sheari Gertsch 1992, C. sprousei Gertsch 1992, C. stowersi Gertsch 1992, C. suttoni Gertsch 1992, C. travisae Gertsch 1992, C. troglobia Cokendolpher 2004, C. ubicki Gertsch 1992, C. uvalde Gertsch 1992, C. venefica Gertsch 1992, C. venii Gertsch 1992, C. vespera Gertsch 1992, C. vibora Gertsch 1992, C. wartoni Gertsch 1992, C. watersi Gertsch 1992 and C. wiltoni Gertsch 1992. We provide, in a series of maps, a first visual assessment of the distribution of these troglobites. Several problems became evident from our examination of the data, including potential synonymies, conflicting distributions, damaged types, potential mislabeling, species known only from one sex, misevaluation of intraspecific variability, and unknown location of type localities. A reliable taxonomic basis for the eyeless members of this genus is particularly important for cave conservation and management because the particular conservation status of these troglobites, particularly for four species that are included on the U.S. Federal list of endangered species.

scholarly journals Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types

Zootaxa ◽  
2007 ◽  
Vol 1418 (1) ◽  
pp. 1-628 ◽  
Author(s):  
CARL J. FERRARIS
Keyword(s):  
Type Species ◽  
New Genus ◽  
Relevant Information ◽  
Species Group ◽  
Valid Species ◽  
Nominal Species ◽  
New Name ◽  
The Status ◽  
Current Emphasis

A checklist of Recent and fossil catfishes (Order Siluriformes) is presented, summarizing taxonomic literature published through 2005. From 4624 nominal species group names and 810 genus group names, 3093 species are recognized as valid, and are distributed among 478 genera and 36 families. Distributional summaries are provided for each species, and nomenclatural synonymies, including relevant information on all name-bearing types, are included for all taxa. One new name is proposed herein: Clariallabes teugelsi, as a replacement for Clarias (Allabenchelys) dumerili longibarbis David & Poll, 1937, which is preoccupied by Clarias longibarbis Worthington, 1933, but has been treated as a valid species of Clariallabes by Teugels. Acrochordonichthys melanogaster Bleeker, 1854, is designated as type species of Acrochordonichthys Bleeker, 1857, inasmuch as no earlier valid designation has been found. A new genus Pseudobagarius, is proposed for the “pseudobagarius group” of species formerly placed in Akysis. The status of 228 species group names remains unresolved and 31 names based on otoliths ascribed to catfishes are listed but not placed into the checklist. The current emphasis given to catfish taxonomy at present is likely to result in a dramatic increase in the total number of valid taxa as well as major changes in the membership of some of the higher level taxa recognized here.

The status and distribution of Carex subimpressa (Cyperaceae)

1986 ◽  
Vol 64 (1) ◽  
pp. 227-232 ◽  
Author(s):  
A. A. Reznicek ◽  
P. M. Catling
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Natural Populations ◽  
Field Studies ◽  
Diagnostic Character ◽  
Wide Area ◽  
Hybrid Origin ◽  
The Status ◽  
Specific Rank ◽  
Scanning Electron

Carex subimpressa, originally described as a hybrid of C. hyalinolepsis and C. lanuginosa, has been reported over a wide area and beyond the range of C. hyalinolepis. Consequently it has been accorded specific rank. Various aspects of morphology reflected in scatter diagrams as well as intermediate stomatal structure revealed through scanning electron microscopy and sectioning support the hybrid origin as originally proposed. This is further supported by field studies of natural populations where both putative parents were invariably present. Reports from beyond the range of one or both parents are the result of misidentification. The diagnostic character combination includes sparsely pubescent perigynia 4.2–6.4 mm long, with relatively short beaks, leaves 4.5–11 mm wide, and ligules 1.8–9 mm long.

scholarly journals On the taxonomy of Heterarthrus (Hymenoptera, Tenthredinidae), with a review of the West Palaearctic species

2019 ◽  
Vol 72 ◽  
pp. 83-126
Author(s):  
Andrew Liston ◽  
Marko Mutanen ◽  
Matti Viitasaari
Keyword(s):  
Species Group ◽  
Nominal Species ◽  
Acer Pseudoplatanus ◽  
Palaearctic Species ◽  
Populus Balsamifera ◽  
The West ◽  
European Species ◽  
The Status ◽  
Trees And Shrubs ◽  
Eastern Finland

The sawfly genus Heterarthrus is naturally distributed in the Palaearctic, with a single described Oriental species. Their larvae mine in the leaves of trees and shrubs of Salicaceae, Betulaceae, and Sapindaceae (Acer). We here recognise twelve West Palaearctic species as valid, with the status of two additional nominal species group taxa in need of further study: fruticicolum Ermolenko, and smithi Ermolenko. A key to adults of the species occurring in the West Palaearctic is presented. Two new species are described: Heterarthus vikbergi Liston, Mutanen & Viitasaari, sp. nov. from females and males reared from leaf-mines in Populus balsamifera collected in eastern Finland, and Heterarthrus fiora Liston, sp. nov. from females reared from Acer pseudoplatanus. The latter is a widespread European species, previously misidentified as Heterarthrus aceris (Kaltenbach, 1856). New junior subjective synonyms are Phyllotoma aceris Kaltenbach, 1856 of Heterarthrus leucomela (Klug, 1818), H. aihinoensis Haris, 2006 of H. kamtchaticus (Malaise, 1931) sp. rev., and H. imbrosensis Schedl, 1981 of H. wuestneii (Konow, 1905). Lectotypes are designated for Phyllotoma flavicollis Gussakovskij, 1947, P. kamtchatica Malaise, 1931, and Tenthredo ochropoda Klug, 1818.

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