scholarly journals Relating Ediacaran Fronds

Paleobiology ◽  
2017 ◽  
Vol 43 (2) ◽  
pp. 171-180 ◽  
Author(s):  
T. Alexander Dececchi ◽  
Guy M. Narbonne ◽  
Carolyn Greentree ◽  
Marc Laflamme

AbstractEdiacaran fronds are key components of terminal-Proterozoic ecosystems. They represent one of the most widespread and common body forms ranging across all major Ediacaran fossil localities and time slices postdating the Gaskiers glaciation, but uncertainty over their phylogenetic affinities has led to uncertainty over issues of homology and functional morphology between and within organisms displaying this ecomorphology. Here we present the first large-scale, multigroup cladistic analysis of Ediacaran organisms, sampling 20 ingroup taxa with previously asserted affinities to the Arboreomorpha, Erniettomorpha, and Rangeomorpha. Using a newly derived morphological character matrix that incorporates multiple axes of potential phylogenetically informative data, including architectural, developmental, and structural qualities, we seek to illuminate the evolutionary history of these organisms. We find strong support for existing classification schema and devise apomorphy-based definitions for each of the three frondose clades examined here. Through a rigorous cladistic framework it is possible to discern the pattern of evolution within and between these clades, including the identification of homoplasies and functional constraints. This work both validates earlier studies of Ediacaran groups and accentuates instances in which previous assumptions of their natural history are uninformative.

IMA Fungus ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi Li ◽  
Lan Jiang ◽  
Ke Wang ◽  
Hai-Jun Wu ◽  
Rui-Heng Yang ◽  
...  

Abstract Different hypotheses have been proposed to interpret the observed unusual ITS (internal transcribed spacer) sequences in Ophiocordyceps sinensis. The coexistence of diverged ITS paralogs in a single genome was previously shown by amplifying the ITS region from mono-ascospore isolates using specific primers designed for different ITS paralog groups. Among those paralogs, are AT-biased ITS sequences which were hypothesized to result from repeat-induced point mutation (RIP). This is a process that detects and mutates repetitive DNA and frequently leads to epigenetic silencing, and these mutations have been interpreted as pseudogenes. Here we investigate the occurrence and frequency of ITS pseudogenes in populations of O. sinensis using large-scale sampling, and discusses the implications of ITS pseudogenes for fungal phylogenetic and evolutionary studies. Our results demonstrate a wide distribution of ITS pseudogenes amongst different geographic populations, and indicate how ITS pseudogenes can contribute to the reconstruction of the evolutionary history of the species.


Zootaxa ◽  
2008 ◽  
Vol 1782 (1) ◽  
pp. 1 ◽  
Author(s):  
NICO M. FRANZ

Cotithene Voss, a previously monotypic genus of Neotropical derelomine flower weevils (Curculionidae: Derelomini), is revised, with provision of a key to the species, cladistic analysis and notes on its natural history. The following six new species are described: C. anaphalanta (Costa Rica), C. dicranopygia (Costa Rica), C. leptorhamphis (Costa Rica, Panama), C. melanoptera (Venezuela), C. stratiotricha (Costa Rica) and C. trigaea (Costa Rica). The monophyly of Cotithene is supported by the characters of a dorsomedially expanded, carinate rostrum, ventrally angulate head, long and anteriorly directed setation on the anterior margin of the prosternum and an apicodorsally expanded aedeagus with paired sclerites in the male, and subcontiguous to separated procoxal cavities in the female. Particularly the males of several species have intriguing and allometrically scaled modifications on the head (triangular projections, long setae) and pronotum (expansion, tumescences), which possibly play a role in male-to-male conflicts. Cotithene species are specialized to visit and reproduce on a narrow range of typically closely related species of Cyclanthaceae. The adults do not function as pollinators, and the herbivorous larvae develop in the fruiting organs of their hosts, frequently triggering the abortion of infructescences. An analysis of 12 taxa (5 outgroup, 7 ingroup) and 32 morphological characters yielded a single most parsimonious cladogram (L = 38, CI = 89, RI = 93) with the topology (C. dicranopygia, (C. stratiotricha, ((C. leptorhamphis, C. trigaea), (C. globulicollis Voss, (C. anaphalanta, C. melanoptera))))). The evolution of morphological traits and host shifts is examined in light of the proposed phylogeny.


2015 ◽  
Vol 33 (15_suppl) ◽  
pp. e15120-e15120
Author(s):  
Humaid Obaid Al-Shamsi ◽  
Reham Abdel-Wahab ◽  
Manal Hassan ◽  
Gehan Botrus ◽  
Ahmed S Shalaby ◽  
...  

2011 ◽  
Vol 279 (1726) ◽  
pp. 3-14 ◽  
Author(s):  
Megan L. Porter ◽  
Joseph R. Blasic ◽  
Michael J. Bok ◽  
Evan G. Cameron ◽  
Thomas Pringle ◽  
...  

Opsin proteins are essential molecules in mediating the ability of animals to detect and use light for diverse biological functions. Therefore, understanding the evolutionary history of opsins is key to understanding the evolution of light detection and photoreception in animals. As genomic data have appeared and rapidly expanded in quantity, it has become possible to analyse opsins that functionally and histologically are less well characterized, and thus to examine opsin evolution strictly from a genetic perspective. We have incorporated these new data into a large-scale, genome-based analysis of opsin evolution. We use an extensive phylogeny of currently known opsin sequence diversity as a foundation for examining the evolutionary distributions of key functional features within the opsin clade. This new analysis illustrates the lability of opsin protein-expression patterns, site-specific functionality (i.e. counterion position) and G-protein binding interactions. Further, it demonstrates the limitations of current model organisms, and highlights the need for further characterization of many of the opsin sequence groups with unknown function.


2015 ◽  
Vol 29 (2) ◽  
pp. 191 ◽  
Author(s):  
James K. Liebherr ◽  
Nick Porch

A late Holocene but prehistoric carabid beetle fauna from the lowland Makauwahi Cave, Kauai, is characterised. Seven extinct species – Blackburnia burneyi, B. cryptipes, B. godzilla, B. menehune, B. mothra, B. ovata and B. rugosa, spp. nov. (tribe Platynini) – represent the first Hawaiian insect species to be newly described from subfossil specimens. Four extant Blackburnia spp. – B. aterrima (Sharp), B. bryophila Liebherr, B. pavida (Sharp), and B. posticata (Sharp) – and three extant species of tribe Bembidiini – Bembidion ignicola Blackburn, B. pacificum Sharp and Tachys oahuensis Blackburn – are also represented. All subfossil fragments are disarticulated, with physical dimensions and cladistic analysis used to associate the major somites – head, prothorax and elytra – for description of the new species. The seven new Makauwahi Cave species support recognition of a lowland area of endemism adjoining Haupu, a low-stature 700 m elevation ridgeline in southern Kauai. Four of the extinct Blackburnia are adelphotaxa to extant species currently found at higher elevations in Kauai. Addition of these lowland specialists to the phylogenetic hypothesis undercuts applicability of the taxon cycle for interpreting evolutionary history of these taxa. Two of the extinct species are Kauai representatives in clades that subsequently colonised younger Hawaiian Islands, enhancing support for the progressive biogeographic colonisation of the archipelago by this lineage. And three of the extinct Blackburnia species comprised larger beetles than those of any extant Kauai Blackburnia, consistent with the evolution of island gigantism in the lowland habitats of Kauai.


2021 ◽  
Vol 118 (10) ◽  
pp. e2019865118
Author(s):  
Yilun Yu ◽  
Chi Zhang ◽  
Xing Xu

Reconstructing the history of biodiversity has been hindered by often-separate analyses of stem and crown groups of the clades in question that are not easily understood within the same unified evolutionary framework. Here, we investigate the evolutionary history of birds by analyzing three supertrees that combine published phylogenies of both stem and crown birds. Our analyses reveal three distinct large-scale increases in the diversification rate across bird evolutionary history. The first increase, which began between 160 and 170 Ma and reached its peak between 130 and 135 Ma, corresponds to an accelerated morphological evolutionary rate associated with the locomotory systems among early stem birds. This radiation resulted in morphospace occupation that is larger and different from their close dinosaurian relatives, demonstrating the occurrence of a radiation among early stem birds. The second increase, which started ∼90 Ma and reached its peak between 65 and 55 Ma, is associated with rapid evolution of the cranial skeleton among early crown birds, driven differently from the first radiation. The third increase, which occurred after ∼40 to 45 Ma, has yet to be supported by quantitative morphological data but gains some support from the fossil record. Our analyses indicate that the bird biodiversity evolution was influenced mainly by long-term climatic changes and also by major paleobiological events such as the Cretaceous–Paleogene (K–Pg) extinction.


Zootaxa ◽  
2009 ◽  
Vol 2087 (1) ◽  
pp. 1-36
Author(s):  
HAO HUANG ◽  
CHANG-CHIN CHEN

A checklist of the genus Platycerus Geoffroy is updated. A method for the observation of endophallus is introduced and used for the study of four species of Platycerus from China. The morphology of Chinese species of Platycerus is reviewed, and all the useful morphological characters are clarified. A character matrix is made to accumulate all the current information on morphology of Chinese species. Platycerus yingqii sp. nov. is described from the northern slope of Mount Taibaishan, southern Shaanxi, China. This new species is similar to Platycerus rugosus, but can be distinguished by male with a browner dorsal surface, remarkably shorter tarsi, lighter and redder ventrites, shorter gap between incisor teeth and mola, male genitalia with different endophallus, female with shorter metatarsi, and female genitalia with the inner apex of hemisternite not protruding beyond the outer apex. The morphological characters of the other three species from China are also studied. A key to the geographical species groups of Platycerus is presented. Keys to the Chinese species are provided for both males and females. Finally some natural history notes are given for some species of Platycerus from China.


Zootaxa ◽  
2009 ◽  
Vol 2270 (1) ◽  
pp. 1-38 ◽  
Author(s):  
IAN CHRISTOPHER STOCKS

The monophyletic agelenid genus Barronopsis Chamberlin & Ivie is revised to include 6 species. The Cuban species B. campephila Alayón and B. cesari Alayón are synonomized under B. barrowsi (Gertsch) and B. jeffersi (Muma), respectively, and B. stephaniae new species is described. Natural history observations, distribution maps, diagnoses and descriptions, and a species identification key including B. texana (Gertsch), B. arturoi Alayón, and B. floridensis (Muma) are provided. Detailed descriptions of the male palpus and female genitalia, a review and evaluation of historical terminology used to describe agelenid palpal bulbs, and a discussion of the utility of certain male palpal characters in resolving phylogeny within Agelenidae are provided. Based on the morphology of the male and female genitalia and morphometric data, two species groups are recognized: a large-bodied B. texana species group (B. texana, floridensis, arturoi, jeffersi) and a small-bodied B. barrowsi species group (B. barrowsi, B. stephaniae). A cladistic analysis of Barronopsis, using Tortolena glaucopis (F. O. P.-Cambridge), Melpomene singula (Gertsch & Ivie), and species of Agelenopsis Giebel as outgroups identified three most parsimonious trees of 37 steps. The strict consensus tree yielded the following species relationships: (Agelenopsis (((B. texana, B. jeffersi), B. floridensis, B. arturoi), (B. barrowsi, B. stephaniae))))).Key words: Agelenopsis, revision, taxonomy, phylogenetic analysis


2019 ◽  
Vol 104 (11) ◽  
pp. 5120-5135 ◽  
Author(s):  
Baris Akinci ◽  
Elif A Oral ◽  
Adam Neidert ◽  
Diana Rus ◽  
Wendy Y Cheng ◽  
...  

Abstract Context Limited natural history data are available in patients with non-HIV–related lipodystrophy syndromes who never received disease-specific therapies, making interpretation of benefits of therapies in lipodystrophy syndromes challenging. Objective We assessed the natural history of non-HIV–related generalized lipodystrophy (GL) and partial lipodystrophy (PL) in patients who have never received leptin or other lipodystrophy-specific therapies. Design/Setting/Patients We conducted an international chart review of 230 patients with confirmed GL or PL at five treatment centers who never received leptin or other lipodystrophy-specific therapies. Patients were observed from birth to loss to follow-up, death, or date of chart abstraction. Outcome Measures Lifetime prevalence of diabetes/insulin resistance and select organ abnormalities, time to diabetes/insulin resistance, first organ abnormality, disease progression, and mortality were described. Results Diabetes/insulin resistance was identified in 58.3% of patients. Liver abnormalities were the most common organ abnormality (71.7%), followed by kidney (40.4%), heart (30.4%), and pancreatitis (13.0%). Kaplan-Meier estimates of mean (SE) time to first organ abnormality were 7.7 years (0.9) in GL and 16.1 years (1.5) in PL (P < 0.001). Mean time to diabetes/insulin resistance was 12.7 years (1.2) in GL and 19.1 years (1.7) in PL (P = 0.131). Mean time to disease progression was 7.6 years (0.8) and comparable between GL and PL subgroups (P = 0.393). Mean time to death was 51.2 years (3.5) in GL and 66.6 years (1.0) in PL (P < 0.001). Conclusions This large-scale study provides comprehensive, long-term data across multiple countries on the natural history of non-HIV–related lipodystrophy.


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