scholarly journals The revival of a so-called rotten fish: the ontogeny of the Devonian acanthodian Triazeugacanthus

2015 ◽  
Vol 11 (2) ◽  
pp. 20140950 ◽  
Author(s):  
Marion Chevrinais ◽  
Richard Cloutier ◽  
Jean-Yves Sire
Keyword(s):  
Original Description ◽  
Size Increase ◽  
Late Devonian ◽  
Allometric Growth ◽  
Ontogenetic Changes ◽  
The Past ◽  
Ontogenetic Stages ◽  
Size Series

Since its original description as a chordate, the Late Devonian Scaumenella mesacanthi has been interpreted alternately as a prochordate, a larval ostracoderm and an immature acanthodian. For the past 30 years, these minute specimens were generally considered as decayed acanthodians, most of them belonging to Triazeugacanthus affinis. Among the abundant material of ‘ Scaumenella ’, we identified a size series of 188 specimens of Triazeugacanthus based on otolith characteristics. Despite taphonomic alteration, we describe proportional growth and progressive appearance of skeletal elements through size increase. Three ontogenetic stages are identified based on squamation extent, ossification completion and allometric growth. We demonstrate that what has been interpreted previously as various degrees of decomposition corresponds to ontogenetic changes.

scholarly journals Insight on the anatomy, systematic relationships, and age of the Early Cretaceous ankylopollexian dinosaur Dakotadon lakotaensis

2015 ◽  
Author(s):  
Clint A Boyd ◽  
Darrin C Pagnac
Keyword(s):  
Early Cretaceous ◽  
Original Description ◽  
Field Work ◽  
Optimality Criteria ◽  
Dorsal Vertebra ◽  
The Past ◽  
Caudal Vertebrae ◽  
Systematic Relationships ◽  
Preparation Work ◽  
Extensive Deformation

Knowledge regarding the early evolution within the dinosaurian clade Ankylopollexia drastically increased over the past two decades, in part because of an increase in described taxa from the Early Cretaceous of North America. These advances motivated the recent completion of extensive preparation and conservation work on the holotype and only known specimen of Dakotadon lakotaensis, a basal ankylopollexian from the Lakota Formation of South Dakota. That specimen (SDSM 8656) preserves a partial skull, lower jaws, a single dorsal vertebra, and two caudal vertebrae. That new preparation work exposed several bones not included in the original description and revealed that other bones were previously misidentified. The presence of extensive deformation in areas of the skull is also noted that influenced inaccuracies in prior descriptions and reconstructions of this taxon. In addition to providing an extensive re-description of D. lakotaensis, this study reviews previously proposed diagnoses for this taxon, identifies two autapomorphies, and provides an extensive differential diagnosis. Dakotadon lakotaensis is distinct from the only other ankylopollexian taxon known from the Lakota Formation, Osmakasaurus depressus, in the presence of two prominent, anteroposteriorly oriented ridges on the ventral surfaces of the caudal vertebrae, the only overlapping material preserved between these taxa. The systematic relationships of D. lakotaensis are evaluated using both the parsimony and posterior probability optimality criteria, with both sets of analyses recovering D. lakotaensis as a non-hadrosauriform ankylopollexian that is more closely related to taxa from the Early Cretaceous (e.g., Iguanacolossus, Hippodraco, and Theiophytalia) than to more basally situated taxa from the Jurassic (e.g., Camptosaurus, Uteodon). This taxonomic work is supplemented by field work that relocated the type locality, confirming its provenance from unit L2 (lower Fuson Member equivalent) of the Lakota Formation. Those data, combined with recently revised ages for the members of the Lakota Formation based on charophyte and ostracod biostratigraphy, constrain the age of this taxon to the late Valanginian to early Barremian.

scholarly journals Shaping our Taxonomic Legacy through Openly Sharing Primary Biodiversity Data in Taxonomic Revisions

2019 ◽  
Vol 3 ◽  
Author(s):  
Torsten Dikow
Keyword(s):  
Data Dissemination ◽  
Original Description ◽  
Published Data ◽  
Data Standards ◽  
Global Biodiversity Information Facility ◽  
High Quality ◽  
Data Repositories ◽  
The Past ◽  
Text Document ◽  
Digital Format

Taxonomy has a long tradition of describing earth’s biodiversity. For the past 20 years or so, taxonomic revisions have become available in PDF format, which is regarded by most practicing taxonomists to be a good means of digital dissemination. However, a PDF document is nothing more than a text document that can be transferred easily for viewing among researchers and computer platforms. In today’s world, traditional taxonomic techniques need to be met with novel tools to make data dissemination a reality, make species hypotheses more robust, and open the field up to rigorous scientific testing. Here, I argue that high-quality taxonomic output is not just the publication of detailed species descriptions and re-descriptions, precise taxon delimitations, easy-to-use identification keys, and comprehensively undertaken and illustrated revisions. Rather, in addition high-quality taxonomic output embraces digital workflows and data standards to disseminate captured and published data in structured, machine-readable formats to data repositories so as to make all data openly accessible. Imagine that a taxonomist today has every original description and every subsequent re-description of a species at her/his fingertips online, has every specimen photograph produced by a previous reviser digitally available in the original resolution, and can take advantage of existing, openly accessible data and resources produced by peers in digital format in the past. When we as taxonomists provide such findable, accessible, interoperable, and reusable (FAIR) data, the future of biodiversity discovery will accelerate and our own taxonomic legacy will be enhanced. Cybertaxonomic tools provide methods to accomplish this goal and their use and implementation is here summarized in the context of revisionary taxonomy from the standpoint of a publishing taxonomist. While many of the tools have been around for some time now, very few taxonomists embrace and utilize these tools in their publications. This presentation will provide information on what kind of data can and should be openly shared (e.g., specimen occurrence data, digital images, names, descriptions, authors) and outline best practices utilizing globally unique identifiers for specimens and data. Data standards and the best-suited data repositories such as the Global Biodiversity Information Facility (GBIF) and Zenodo, with its Biodiversity Literature Repository, and the Plazi TreatmentBank, an emerging species portal, are discussed to illustrate retrospective and prospective data capture of taxonomic revisions.

scholarly journals Loss in the making: absence of pelvic fins and presence of paedomorphic pelvic girdles in a Late Devonian antiarch placoderm (jawed stem-gnathostome)

2018 ◽  
Vol 14 (6) ◽  
pp. 20180199 ◽  
Author(s):  
France Charest ◽  
Zerina Johanson ◽  
Richard Cloutier
Keyword(s):  
Elemental Composition ◽  
Developmental Plasticity ◽  
Late Devonian ◽  
Ontogenetic Changes ◽  
Endochondral Bone ◽  
Early Devonian ◽  
Secondary Loss ◽  
Paired Female ◽  
Female Genital

Within jawed vertebrates, pelvic appendages have been modified or lost repeatedly, including in the most phylogenetically basal, extinct, antiarch placoderms. One Early Devonian basal antiarch, Parayunnanolepis , possessed pelvic girdles, suggesting the presence of pelvic appendages at the origin of jawed vertebrates; their absence in more derived antiarchs implies a secondary loss. Recently, paired female genital plates were identified in the Late Devonian antiarch, Bothriolepis canadensis , in the position of pelvic girdles in other placoderms. We studied these putative genital plates along an ontogenetic series of B. canadensis ; ontogenetic changes in their morphology, histology and elemental composition suggest they represent endoskeletal pelvic girdles composed of perichondral and endochondral bone. We suggest that pelvic fins of derived antiarchs were lost, while pelvic girdles were retained, but reduced, relative to Parayunnanolepis . This indicates developmental plasticity and evolutionary lability in pelvic appendages, shortly after these elements evolved at the origin of jawed vertebrates.

The development of a morphological class

1990 ◽  
Vol 2 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Gregory R. Guy ◽  
Sally Boyd
Keyword(s):  
Young Adults ◽  
Age Distribution ◽  
Adult Life ◽  
High Rate ◽  
Past Tense ◽  
The Past ◽  
Deletion Rate ◽  
Ontogenetic Stages ◽  
Different Ages ◽  
Children's Speech

ABSTRACTEnglish has a class of “semiweak” verbs, which in the past tense have root-vowel ablaut as well as reflexes of the apical stop suffix, for example, kept, told. This study traces the development of this class in a sample of speakers aged 4–65. The evidence is derived from the variable rates of occurrence of the final -t,d in these words in the speech of individuals of different ages. The rate of -t,d absence in semiweak verbs systematically declines with increasing age. We identify three ontogenetic stages in the development of the class. In children's speech, these segments rarely appear, suggesting they are underlyingly absent. In young adults they appear but undergo the variable -t,d deletion process of English at the same high rate as noninflectional -t,d in words like west, old, implying that such speakers do not treat them as affixes. Finally, some adult speakers show a lowered deletion rate, suggesting that they accord the final stops separate morphemic status. The age distribution of this pattern implies that speakers only arrive at this analysis in adult life, after the age when acquisition is often assumed to be complete.

"Rational hope" in the early treatment of Parkinson's disease

1999 ◽  
Vol 77 (6) ◽  
pp. 375-382 ◽  
Author(s):  
Theodore L Sourkes
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Drug Treatment ◽  
Early Treatment ◽  
Original Description ◽  
Anticholinergic Drugs ◽  
The Past ◽  
Modes Of Action

The drug treatment of Parkinson's disease since the original description of the malady in 1817 is described. Consideration is given to the historic use of alkaloids of the belladonna, harmala, and aporphine families, and of amphetamine. The introduction of the L-dopa treatment is described. The modes of action of the various drugs employed in the past as well as those in current use are described in the context of knowledge of the functioning of the nigrostriatal tract.Key words: anticholinergic drugs, apomorphine, bulbocapnine, L-dopa, harmine.

Four new species of the interstitial family Cobanocytheridae (Crustacea: Ostracoda) from central Japan

Zootaxa ◽  
2011 ◽  
Vol 2924 (1) ◽  
pp. 33 ◽  
Author(s):  
RYOUICHI HIGASHI ◽  
AKIRA TSUKAGOSHI
Keyword(s):  
Original Description ◽  
Galapagos Islands ◽  
Oceanic Islands ◽  
Galápagos Islands ◽  
Central Japan ◽  
The Past ◽  
Eurasian Continent ◽  
Continental Islands ◽  
The Japanese Archipelago ◽  
North Western

Four interstitial cobanocytherid species are described from central Japan: Cobanocythere ikeyai sp. nov., Cobanocythere lata sp. nov., Paracobanocythere watanabei sp. nov. and Paracobanocythere grandis sp. nov. The reports of the two new Paracobanocythere species are the second and third for this genus since the original description of P. hawaiiensis Gottwald, 1983. Cobanocythere ikeyai sp. nov., and C. lata sp. nov., from Japan are morphologically more similar to the species of the “lanceolata group” by Gottwald (1983) and C. guttaeformis Gottwald, 1983 from the Galapagos Islands, respectively, rather than to other Cobanocythere species from Japan. The Japanese archipelago (eastern Eurasian Continent) and the Galapagos Islands (north-western South America) are separated by about 15,000 km from each other, and have never been adjoined throughout geological history. This fact, and also the morphological similarities between Cobanocythere species from Japan and the Galapagos Islands, suggests that this genus may have undergone global dispersal at several times in the past. Conversely, the genera Cobanocythere and Paracobanocythere are distributed not only around continents and continental islands but also around oceanic islands such as the Hawaiian and Galapagos Islands. We conclude, therefore, that the cobanocytherids seem to have been able to disperse long distances across oceans.

A new species of the Jurassic (Callovian) brachiopod Septirhynchia from northern Sinai

1987 ◽  
Vol 61 (6) ◽  
pp. 1156-1172 ◽  
Author(s):  
Howard R. Feldman
Keyword(s):  
New Species ◽  
Ontogenetic Changes ◽  
Median Septum ◽  
Ontogenetic Stages ◽  
First Time ◽  
A New Species

Septirhynchia hirschi n. sp. is described from the Callovian (Jurassic) strata of Gebel El-Maghara, northern Sinai, Egypt. Significant ontogenetic changes from juvenile to adult include: 1) increase in height of the ventral median septum; 2) change from hypothyridid to mesothyridid pedicle foramen; 3) change from a pyriform to a gibbous outline; 4) change from a weakly defined to a strongly defined pedicle sulcus; and 5) change from a relatively straight to a strongly arched lateral commissure. All ontogenetic stages, except for neanic, possessed a pedicle tube. Muscle scars (diductor) were observed for the first time in the genus on several pedicle valve interiors; none were noted on any brachial valve interiors. Juveniles lived epifaunally, attached to the substrate by a small but functional pedicle, while adults lived semi-infaunally with the umbos buried in the mud.

A review of the type material of Coccinellidae (Coleoptera) described by F.W. Hope, and by E. Mulsant in the Hope Entomological Collections, Oxford

1989 ◽  
Vol 20 (3) ◽  
pp. 343-370 ◽  
Author(s):  
R.G. Booth ◽  
R.D. Pope
Keyword(s):  
Natural History ◽  
British Museum ◽  
Original Description ◽  
Type Material ◽  
New Combinations ◽  
The Past ◽  
Single Exception ◽  
University Museum

AbstractThe type material of Coccinellidae described by F.W. Hope and by E. Mulsant from the collections of F.W. Hope and J.O. Westwood is reviewed. Lectotypes for Hope's species are designated (with a single exception) from material in the British Museum (Natural History). The majority oflectotypes for Mulsant's species described from Hope's and Westwood's material is located in the Hope Entomological Collections, University Museum, Oxford. The identity of a species is discussed where confusion concerning a name has occurred in the past, or where the current interpretation differs from the original description or type material. Brachiacantha bipartita Mulsant is resurrected from synonymy with B. westwoodii Mulsant. The following new synonymies are recorded (valid name first): Ballida brahamae Mulsant = Palaeoeneis aurantiaca Crotch = Eoneda sumatrensis Iablokoff-Khnzorian; Calvia quattuordecimguttata (Linnaeus) = Oenopia dorsonotata Mulsant; Calvia vulnerata (Hope) = C. uniramosa (Hope) = C. flaccida Mulsant = C. vishnu (Crotch) = C. krishna (Crotch) = C. buddha (Crotch); Coelophora saucia (Mulsant) = Lemnia melanota Mulsant; Rodolia sexnotata (Mulsant) = R. guerinii (Crotch); Scymnus nubilus Mulsant = S. curtisii Mulsant = S. lateralis Sicard. The following are new combinations: Afidentula stephensi (Mulsant) (from Epilachna); Horniolus guimeti (Mulsant) (from Scymnus); Rhyzobius waterhousei (Mulsant) (from Scymnus); Rodolia sexnotata (Mulsant) (from Epilachna).

scholarly journals A Diagnostic Guide for Volutella Blight Affecting Buxaceae

2021 ◽  
Author(s):  
Xiao Yang ◽  
Vanina Lilián Castroagudín ◽  
Margery Daughtrey ◽  
Andrew Loyd ◽  
Jerry E Weiland ◽  
...  
Keyword(s):  
Signs And Symptoms ◽  
Original Description ◽  
Detailed Comparison ◽  
Morphological Characters ◽  
Common Disease ◽  
Pathogenicity Test ◽  
Plant Family ◽  
The Past ◽  
Blight Disease ◽  
New Research

Volutella blight is a common disease of species in the plant family Buxaceae, specifically boxwood, pachysandra and sarcococca. Despite the disease has been consistently found over the past 150 years in all continents except for Antarctica, there are numerous complications in its etiology, signs and symptoms, and taxonomy, morphology, isolation, and preservation methods of its causal pathogens. For example, one of the two pathogens causing Volutella blight on boxwood, Pseudonectria buxi, has gone by at least 25 names including Volutella buxi and P. rousseliana, since its original description in 1815. The other Volutella blight pathogen on boxwood, P. foliicola, was not described until 2015. Although Coccinonectria pachysandricola, previously named as V. pachysandricola, has been known as a pathogen of pachysandra since 1944, it is only recently found in 2019 that the same pathogen can infect sarcococca. In this diagnostic guide, we provide a comprehensive review on the taxonomy, symptoms, host range, distribution, isolation, identification, storage, and pathogenicity test of the Volutella blight disease and these three causal pathogens. New data, such as previously unreported perithecial morphological characters of P. buxi and a unique sporodochia-forming pattern of C. pachysandricola, are also provided in this guide. Furthermore, a detailed comparison of diagnostic traits of three major fungal diseases on boxwood, namely Volutella blight, boxwood blight, and boxwood dieback, is included. This guide aims at providing integrated information to aid the diagnosis of Volutella blight and facilitating new research to advance our knowledge of this old, but under-studied disease.

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