Lattice organs and newly characterized submarginal pore-plates and pore-fields of the carapace in Ascothoracida (Crustacea: Thecostraca)

2020 ◽  
Vol 40 (6) ◽  
pp. 781-794 ◽  
Author(s):  
Mark J Grygier ◽  
Waltraud Klepal
Keyword(s):  
Developmental Stages ◽  
Character State ◽  
Hinge Line ◽  
Ground Pattern ◽  
Valve Margin ◽  
State Variation ◽  
Unidentified Species ◽  
Lattice Organs ◽  
First Time ◽  
Number Form

Abstract Lattice organs on the dorsal part of the carapace were examined by scanning electron microscopy (SEM) in females, males, and/or cypridiform ascothoracid-larvae (in the ascothoracid-larva I stage, for the first time ever) of six species of Ascothoracida representing four genera and three families: Waginella sandersi (Newman, 1974), W. ?metacrinicola (Okada, 1926), and Gorgonolaureus muzikaeGrygier, 1981 (family Synagogidae); BaccalaureusBroch 1929, unidentified species (Lauridae); and Ascothorax gigasWagin, 1968 and A. synagogoides (Wagin, 1964) (Ascothoracidae). All were of the “keel in a trough” or “tube in a trough” type, but they varied even more than those of previously studied ascothoracidans in number, form, orientation, and terminal pore position. Such extensive variability, summarized graphically herein, limits the potential utility of Ascothoracida (parasites of anthozoans and echinoderms) as an out-group for polarizing lattice organ character-state variation in Cirripedia (free-living and parasitic barnacles). While the ground-pattern of lattice organs in Thecostraca (comprising Ascothoracida, Cirripedia, and Facetotecta, or “y-larvae”) includes two anterior and three posterior pairs, ascothoracid-larvae and males of AscothoraxDjakonov, 1914 and DendrogasterKnipovich, 1890 (family Dendrogastridae) have only two posterior pairs; evidence as to which pair is missing is discussed. The hypothesis that dorsal setae in thecostracan nauplii are the precursors of lattice organs in later developmental stages is reexamined; one-to-one positional matching of such setae to lattice organs is difficult in Ascothoracida. Newly characterized structures of unknown function, termed “reticulated pore-plates”, exist along the hinge line in a juvenile male of G. muzikae. The “pits” reported earlier along the anterior valve margin in ascothoracid-larva II of A. synagogoides are actually clusters of pores that may be homologous to these pore-plates. Potentially homologous pore-fields in other ascothoracidans are reviewed from the literature or described anew using SEM.

Character state variation among species of Thrips genus (Thysanoptera) in Malaysia, with one new species and two new records

Zootaxa ◽  
2020 ◽  
Vol 4852 (2) ◽  
pp. 239-245
Author(s):  
Y. F. NG ◽  
L. A. MOUND
Keyword(s):  
New Species ◽  
Abdominal Segment ◽  
New Records ◽  
Peninsular Malaysia ◽  
Character State ◽  
State Variation ◽  
Segment Viii ◽  
First Time ◽  
One New Species

Thrips korbuensis sp.n. is described from a high elevated area in Peninsular Malaysia. It shares many character states with Thrips coloratus but has 8-segmented antennae and abdominal segment VIII–X uniformly dark. It also shares some features with Thrips florum, and variation in some character states used to distinguish species in the Thrips hawaiiensis group are discussed. Two species, Thrips brevistylus and Thrips subnudula, are recorded for the first time from Malaysia, and an updated checklist is provided of 27 species of the genus Thrips recorded from Malaysia. 

scholarly journals Probing the floral developmental stages, bisexuality and sex reversions in castor (Ricinus communis L.)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sujatha Thankeswaran Parvathy ◽  
Amala Joseph Prabakaran ◽  
Thadakamalla Jayakrishna
Keyword(s):  
Developmental Stages ◽  
Ricinus Communis ◽  
Sex Expression ◽  
Pistil Abortion ◽  
Ricinus Communis L ◽  
Sex Reversion ◽  
Stage 4 ◽  
Meristem Development ◽  
Male Specific ◽  
First Time

AbstractCastor (Ricinus communis L) is an ideal model species for sex mechanism studies in monoecious angiosperms, due to wide variations in sex expression. Sex reversion to monoecy in pistillate lines, along with labile sex expression, negatively influences hybrid seed purity. The study focuses on understanding the mechanisms of unisexual flower development, sex reversions and sex variations in castor, using various genotypes with distinct sex expression pattern. Male and female flowers had 8 and 12 developmental stages respectively, were morphologically similar till stage 4, with an intermediate bisexual state and were intermediate between type 1 and type 2 flowers. Pistil abortion was earlier than stamen inhibition. Sex alterations occurred at floral and inflorescence level. While sex-reversion was unidirectional towards maleness via bisexual stage, at high day temperatures (Tmax > 38 °C), femaleness was restored with subsequent drop in temperatures. Temperature existing for 2–3 weeks during floral meristem development, influences sexuality of the flower. We report for first time that unisexuality is preceded by bisexuality in castor flowers which alters with genotype and temperature, and sex reversions as well as high sexual polymorphisms in castor are due to alterations in floral developmental pathways. Differentially expressed (male-abundant or male-specific) genes Short chain dehydrogenase reductase 2a (SDR) and WUSCHEL are possibly involved in sex determination of castor.

scholarly journals Combining QTL Mapping and Gene Expression Analysis to Elucidate the Genetic Control of ‘Crumbly’ Fruit in Red Raspberry (Rubus idaeus L.)

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 794
Author(s):  
Luca M. Scolari ◽  
Robert D. Hancock ◽  
Pete E. Hedley ◽  
Jenny Morris ◽  
Kay Smith ◽  
...  
Keyword(s):  
Genetic Control ◽  
Developmental Disorder ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Microarray Experiment ◽  
Rubus Idaeus ◽  
Red Raspberry ◽  
Genotype By Sequencing ◽  
First Time ◽  
Selection Of

‘Crumbly’ fruit is a developmental disorder in raspberry that results in malformed and unsaleable fruits. For the first time, we define two distinct crumbly phenotypes as part of this work. A consistent crumbly fruit phenotype affecting the majority of fruits every season, which we refer to as crumbly fruit disorder (CFD) and a second phenotype where symptoms vary across seasons as malformed fruit disorder (MFD). Here, segregation of crumbly fruit of the MFD phenotype was examined in a full-sib family and three QTL (Quantitative Trait Loci) were identified on a high density GbS (Genotype by Sequencing) linkage map. This included a new QTL and more accurate location of two previously identified QTLs. A microarray experiment using normal and crumbly fruit at three different developmental stages identified several genes that were differentially expressed between the crumbly and non-crumbly phenotypes within the three QTL. Analysis of gene function highlighted the importance of processes that compromise ovule fertilization as triggers of crumbly fruit. These candidate genes provided insights regarding the molecular mechanisms involved in the genetic control of crumbly fruit in red raspberry. This study will contribute to new breeding strategies and diagnostics through the selection of molecular markers associated with the crumbly trait.

scholarly journals A new species of Xyliphius, a rarely sampled banjo catfish (Siluriformes: Aspredinidae) from the rio Tocantins-Araguaia system

2010 ◽  
Vol 8 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Carlos A Figueiredo ◽  
Marcelo R Britto
Keyword(s):  
New Species ◽  
Conservation Status ◽  
River System ◽  
Character State ◽  
New Taxon ◽  
Posterior Border ◽  
Lower Lip ◽  
Araguaia River ◽  
State Variation ◽  
A New Species

Xyliphius anachoretes, a new species of aspredinid catfish is described from the Tocantins-Araguaia River system. Xyliphius anachoretes is diagnosed by the presence of six developed retrorse serrae on posterior border of pectoral-fin spine, presence of papillae on the lower lip bearing minute branches, and only two dorsal procurrent rays. Comments about the informativeness of character-state variation among Xyliphius species and aspredinid related genera are furnished. Also, a brief discussion about conservation status of the new taxon is made.

scholarly journals Zeiform mouthbrooding in the deepsea – dispelling a myth

2020 ◽  
Author(s):  
Ralf ◽  
G. David Johnson ◽  
Kevin Conway
Keyword(s):  
Deep Water ◽  
Deep Sea ◽  
Developmental Stages ◽  
Extended Period ◽  
Marine Fishes ◽  
Early Developmental Stages ◽  
Water Fish ◽  
First Time ◽  
Early Developmental ◽  
Deep Sea Fauna

Mouthbrooding or oral incubation, the retention of early developmental stages inside of the mouth for an extended period of time, has evolved multiple times in bony fishes1,2. Though uncommon, this form of parental care has been documented and well-studied in several groups of freshwater fishes but is also known to occur in a small number of marine fishes, all inhabiting coastal waters1,2. A recent paper3, reported for the first time mouthbrooding in a deep-water fish species, the zeiform Parazen pacificus, which according to the authors “fills in a gap in the larval literature for this family of fishes and prompts further investigation into other novel reproductive modes of deep-sea fauna.”

Colleters in the vegetative axis of Aechmea blanchetiana (Bromeliaceae): anatomical, ultrastructural and functional aspects

2018 ◽  
Vol 66 (5) ◽  
pp. 379 ◽  
Author(s):  
Igor Ballego-Campos ◽  
Elder Antônio Sousa Paiva
Keyword(s):  
Developmental Stages ◽  
Light And Electron Microscopy ◽  
Secretory Activity ◽  
Functional Roles ◽  
Reproductive Axis ◽  
Functional Aspects ◽  
The Family ◽  
Marginal Cells ◽  
First Time

Colleters are common among eudicotyledons, but few records exist for monocotyledons and other groups of plants. For Bromeliaceae, mucilage secretions that protect the young portions of the plant have been observed only in the reproductive axis, and little is known about the secretory systems behind this or even other kind of secretions in the family. We aimed to describe, for the first time, the occurrence of colleters associated with the vegetative shoot of Aechmea blanchetiana (Baker) L.B.Sm., and elucidate aspects of their structure, ultrastructure and secretory activity. Samples of various portions of the stem axis were prepared according to standard methods for light and electron microscopy. Colleters were found compressed in the axillary portion of leaves and in all leaf developmental stages. Secretory activity, however, was found to be restricted to young and unexpanded leaves. The colleters displayed a flattened hand-like shape formed by a multiseriate stalk and an expanded secretory portion bearing elongated marginal cells. Ultrastructural data confirmed that the secretory role of the colleters is consistent with mucilaginous secretion. The functional roles of the colleters are discussed with regard to environmental context and intrinsic features of the plant, such as the presence of a water-impounding tank.

Development of Haemoglobin by De-embryonated Chick Blastoderms Cultured in vitro and the Effect of Abnormal RNA upon its Synthesis

Development ◽  
1961 ◽  
Vol 9 (1) ◽  
pp. 202-221
Author(s):  
B. R. A. O'Brien
Keyword(s):  
Protein Synthesis ◽  
Developmental Stages ◽  
Specific Protein ◽  
Cytoplasmic Protein ◽  
Whole Cells ◽  
Restricted Group ◽  
Dividing Cells ◽  
First Time ◽  
Structural Code

The embryo provides a sequence of developmental stages in which proteins both structural and enzymatic appear or become detectable for the first time in a restricted group of dividing cells. The cells or tissues can be maintained in vitro for a period that may precede and include the synthesis of a specific ‘cytoplasmic’ protein. In this way systems of protein synthesis within the cells of higher organisms can be studied during those stages in which current hypotheses suggest that some structural code is passed on from the DNA of the nucleus to the cytoplasm where the synthesis of the protein becomes maximal. Acellular preparations have contributed much to the elucidation of protein synthesis, but it is doubtful whether actual net synthesis has been obtained in systems less complex than the ‘protoplast’ developed by Spiegelman (1957). In order to study the synthesis of a specific protein it seems necessary at this stage to use whole cells.

scholarly journals Prenatal development in pterosaurs and its implications for their postnatal locomotory ability

2019 ◽  
Vol 286 (1904) ◽  
pp. 20190409 ◽  
Author(s):  
David Michael Unwin ◽  
D. Charles Deeming
Keyword(s):  
Vertebral Column ◽  
Egg Size ◽  
Developmental Stages ◽  
Prenatal Development ◽  
Limb Bones ◽  
Stage Of Development ◽  
Full Development ◽  
Absolute Requirement ◽  
Near Term ◽  
First Time

Recent fossil finds in China and Argentina have provided startling new insights into the reproductive biology and embryology of pterosaurs, Mesozoic flying reptiles. Nineteen embryos distributed among four species representing three distinct clades have been described and all are assumed to be at, or near, term. We show here how the application of four contrasting quantitative approaches allows a more precise identification of the developmental status of embryos revealing, for the first time to our knowledge, the presence of middle and late developmental stages as well as individuals that were at term. We also identify a predicted relationship between egg size and shape and the developmental stage of embryos contained within. Small elongate eggs contain embryos at an earlier stage of development than larger rounder eggs which contain more fully developed embryos. Changes in egg shape and size probably reflect the uptake of water, consistent with a pliable shell reported for several pterosaurs. Early ossification of the vertebral column, limb girdles and principal limb bones involved some heterochronic shifts in appearance times, most notably of manus digit IV, and facilitated full development of the flight apparatus prior to hatching. This is consistent with a super-precocial flight ability and, while not excluding the possibility of parental care in pterosaurs, suggests that it was not an absolute requirement.

Oxygen consumption by chick embryos exposed to mechanical (shaking) stress

1979 ◽  
Vol 46 (2) ◽  
pp. 298-301
Author(s):  
R. R. Schmidt ◽  
S. Kaplan ◽  
J. J. Smith
Keyword(s):  
Oxygen Consumption ◽  
Developmental Stages ◽  
Chick Embryos ◽  
O2 Consumption ◽  
In Ovo ◽  
Consumption Values ◽  
Induced Stress ◽  
Early Return ◽  
Functionally Impaired ◽  
First Time

Stage 34 (8-day) and 41 (15-day) chick embryos (Gallus gallus; in ovo) were exposed (3 min) to two separate amounts of mechanical (shaking) stress. Oxygen consumption determinations, following a temperature equilibration period (60 min), were made on entire, intact eggs using a Warburg apparatus equipped with 130-ml flasks modified to hold the egg. Shaking at 300 excursions per minute (epm) resulted in depressed O2 consumption by stages 34 and 41. Only stage 34 embryos had markedly depressed O2 consumption values when shaken at 100 epm. When exposed to 300 epm and reincubated for either 1, 2, or 4 hr prior to O2 consumption determinations stage 34 embryos, following an early return to control levels exhibited a marked fall in O2 consumption by 4 h reincubation. The stage 41 embryos, on the other hand, demonstrated a gradual rise to control O2 consumption levels by 4 h reincubation. Oxygen consumption has now been shown for the first time in an embryonic system (at two distinct developmental stages) to be functionally impaired by mechanically induced stress.

scholarly journals Character state variation within Dendrothrips (Thysanoptera: Thripidae) with a revision of the species from China

Zootaxa ◽  
2019 ◽  
Vol 4590 (2) ◽  
pp. 231
Author(s):  
ZHAOHONG WANG ◽  
LAURENCE A. MOUND ◽  
XIAOLI TONG
Keyword(s):  
Sexual Dimorphism ◽  
Fore Wing ◽  
Host Plants ◽  
Wide Distribution ◽  
Wing Surface ◽  
Character State ◽  
State Variation ◽  
Species Groups

Character state variation among species within Dendrothrips Uzel is discussed, with seven species-groups suggested based on sculpture of body and fore wing surface. Sexual dimorphism in pronotal sculpture and posteroangular setae is described in D. magnoliae. The major host plants of several species are indicated, and the wide distribution across Asia of some species emphasised. Species of Dendrothrips from China are reviewed, D. octosparsus sp. n. is described from Oleaceae, and a key presented to the ten species from China. Two species previously known only from Japan, D. magnoliae Kudô and D. latimaculatus Nonaka & Okajima, are newly recorded from China along with the first description of their males. The male of D. homalii Zhang & Tong is described and illustrated. The record from China of D. mendax Bhatti is considered a misidentification of D. latimaculatus. D. schmiae Kudô is synonymized with D. minowai Priesner.

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