Larval morphology of Dart-Poison Frogs (Anura: Dendrobatoidea: Aromobatidae and Dendrobatidae)

Zootaxa ◽  
2013 ◽  
Vol 3637 (5) ◽  
pp. 569 ◽  
Author(s):  
DAVID A. SÁNCHEZ
Keyword(s):  
Digestive System ◽  
Larval Morphology ◽  
Stages Of Development ◽  
Taxonomic Assignment ◽  
Digestive Tube ◽  
Early Stages ◽  
Constant Diameter ◽  
The Family ◽  
Upper Jaw ◽  
Late Stages

Tadpoles in the superfamily Dendrobatoidea (families Aromobatidae and Dendrobatidae), housed in zoological collections or illustrated in publications, were studied. For the most part, tadpoles of species within the family Aromobatidae, the subfamilies Colostethinae and Hyloxalinae (of the family Dendrobatidae), and those of the genus Phyllobates, Dendrobatinae (Dendrobatidae) have slender anterior jaw sheaths with a medial notch and slender lateral processes, triangular fleshy projections on the inner margin of the nostrils and digestive tube with constant diameter and color and its axis sinistrally directed, concealing the liver and other organs. These morphologies are different from the ones observed in tadpoles of species included in the Dendrobatinae (minus Phyllobates). Exceptions to these morphological arrangements are noted, being the digestive system arrangement and the nostril ornamentation more plastic than the shape of the upper jaw sheath. Tadpoles of all species of the Dendrobatoidea have similar disposition of digestive organs in early stages, but differentiate in late stages of development. Classifying the upper jaw sheath into the two recognized states is possible from very early stages of development, but gut disposition and nostril ornamentation cannot be determined until late in development, making classification and taxonomic assignment of tadpoles based on these morphological features challenging.

scholarly journals Arabidopsis glucosinolate storage cells transform into phloem fibres at late stages of development

2019 ◽  
Vol 70 (16) ◽  
pp. 4305-4317 ◽  
Author(s):  
Pascal Hunziker ◽  
Barbara Ann Halkier ◽  
Alexander Schulz
Keyword(s):  
Morphological Changes ◽  
Smooth Endoplasmic Reticulum ◽  
Chemical Defence ◽  
Herbaceous Plant ◽  
Stages Of Development ◽  
Golgi Bodies ◽  
Early Stages ◽  
High Concentrations ◽  
Storage Cells ◽  
Late Stages

Abstract The phloem cap of Arabidopsis thaliana accumulates glucosinolates that yield toxic catabolites upon damage-induced hydrolysis. These defence compounds are stored in high concentrations in millimetre long S-cells. At early stages of development, S-cells initiate a process indicative of programmed cell death. How these cells are maintained in a highly turgescent state following this process is currently unknown. Here, we show that S-cells undergo substantial morphological changes during early differentiation. Vacuolar collapse and rapid clearance of the cytoplasm did not occur until senescence. Instead, smooth endoplasmic reticulum, Golgi bodies, vacuoles, and undifferentiated plastids were observed. Lack of chloroplasts indicates that S-cells depend on metabolite supply from neighbouring cells. Interestingly, TEM revealed numerous plasmodesmata between S-cells and neighbouring cells. Photoactivation of a symplasmic tracer showed coupling with neighbouring cells that are involved in glucosinolate synthesis. Hence, symplasmic transport might contribute to glucosinolate storage in S-cells. To investigate the fate of S-cells, we traced them in flower stalks from the earliest detectable stages to senescence. At late stages, S-cells were shown to deposit thick secondary cell walls and transform into phloem fibres. Thus, phloem fibres in the herbaceous plant Arabidopsis pass a pronounced phase of chemical defence during early stages of development.

scholarly journals STUDIES ON SEEDS

1971 ◽  
Vol 48 (2) ◽  
pp. 387-394 ◽  
Author(s):  
Hilton H. Mollenhauer ◽  
Clara Totten
Keyword(s):  
Electron Microscopy ◽  
Cell Shape ◽  
Stages Of Development ◽  
Early Stages ◽  
Late Stages

Several fixation procedures were studied to determine those most suitable for preservation of seeds during late stages of development and early stages of germination. These are the periods when the tissues are partially dehydrated and are most difficult to fix for electron microscopy. It was found that a prefixation with a mixture of glutaraldehyde, reconstituted formaldehyde (i.e. paraformaldehyde), and acrolein, followed by a postfixation in OsO4 or KMnO4, gives very acceptable images. The results also indicate that glutaraldehyde is necessary for preservation of cell shape, paraformaldehyde for stabilization of reserve proteins, and acrolein for rapid penetration of tissues. Phosphate, cacodylate, and collidine are all acceptable buffers, although collidine gives the most consistent results.

The internal anatomy of the woodlouse, Metoponorthus pruinosus (Brandt), (Porcellionidae, Peracarida)

1968 ◽  
Vol 46 (3) ◽  
pp. 321-327 ◽  
Author(s):  
M. A. Alikhan
Keyword(s):  
Nervous System ◽  
Digestive System ◽  
Circulatory System ◽  
Reproductive Organs ◽  
The Body ◽  
Internal Anatomy ◽  
Suboesophageal Ganglion ◽  
Digestive Tube ◽  
Thoracic Ganglia ◽  
Digestive Glands

Tbe circulatory system, lying in the mid-dorsal line of the body, consists of an oval heart, the opthalmic artery, and a dorsal abdominal artery.The digestive system comprises a wide, large alimentary tube and two pairs of digestive glands. An oesophagus, a proventriculus, midgut, and a short proctodacum or hindgut form the digestive tube. The digestive glands are very well developed and are beaded in form; each pair lies on either side of the alimentary canal.The reproductive organs are well developed in both sexes: in the male they consist of paired testes and their vas deferentia, and in the female paired bilobed ovaries and oviducts.A cerebral or supraoesophageal ganglion, a suboesophageal ganglion, and seven thoracic ganglia form the nervous system. The supraoesophageal ganglion is united with the suboesophageal ganglion by means of the circumoesophageal commissures, whereas the thoracic ganglia and suboesophageal ganglia are linked with each other by paired connectives.The gills and the tracheae are the organs of respiration. The gills are borne of the bases of the pleopods and are enclosed in the branchial chamber. The tracheae are located on the lateral lobes of the first two pleopods only.

Comparative leaf development of aerial and aquatic growth forms of Myriophyllum aquaticum

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 421-430 ◽  
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Epidermal Cells ◽  
The Other ◽  
Developmental Study ◽  
Growth Forms ◽  
Myriophyllum Aquaticum ◽  
Stages Of Development ◽  
Qualitative And Quantitative ◽  
Early Stages ◽  
Other Hand

Myriophyllum aquaticum (Vell.) Verdc. produces two morphologically different forms of leaves based on whether they are aerial or aquatic. The objective of this study was to determine whether there are any similarities or differences between these two growth forms during their early stages of development. A comparative developmental study of aerial and aquatic growth forms of M. aquaticum was conducted from a qualitative and quantitative perspective using a scanning electron microscope. The pattern of leaf and lobe initiation such as their origin and shape were similar in both growth forms until the fourth plastochron (stage P4). Differences between the two growth forms became evident from stage P5 onward, where a larger shoot apical meristem (SAM), elongated epidermal cells, shorter and slightly more numerous lobes, as well as the presence of appendage-like structures characterized aquatic growth forms. On the other hand, aerial growth forms had smaller SAM, bulb-like epidermal cells, and longer and slightly less numerous leaf lobes. Significant differences between growth forms were noted for parameters such as volume of SAM, length of terminal, first, and middle lobes, as well as the length from first to last lobes. The volume of the SAM of aquatic shoot tips was always greater than aerial forms. On the other hand, lobes of aerial forms were always longer than the aquatic counterpart during early stages of development. This study on the development of M. aquaticum shows that the aerial and aquatic growth forms diverge from their early stages of development.

XV. On the development of the parasitic isopoda

1878 ◽  
Vol 169 ◽  
pp. 505-521 ◽  
Keyword(s):  
The Body ◽  
The Other ◽  
Stages Of Development ◽  
Early Stages ◽  
Abdominal Appendages ◽  
Pair Of Antennae

The following paper contains an account of observations on the development of the species Cymothoa œstroides and C . parallela of Milne Edwards; but the forms of the young seem to show that several species are really included under these two names. In the early stages of development the only observable difference that exists between the embryos is one of size, but in the later stages they differ very markedly from each other in their external characters. From adult individuals answering the description of C . œstroides I have obtained four varieties of embryos: two with long antennae and two with short.* In the two former the first pair of antennae are but slightly longer than the head, while the second pair are longer than the body; the eyes are small. In one of the varieties thus characterised the abdominal appendages are fringed with long hairs (fig. 20), and in the other they are smooth.

Morphological variations of Phrosina semilunata Risso, 1822 juveniles (Crustacea: Amphipoda: Hyperiidea), new evidence from the Gulf of Mexico

Zootaxa ◽  
2021 ◽  
Vol 4995 (3) ◽  
pp. 594-600
Author(s):  
MARCO VIOLANTE-HUERTA ◽  
LAURA SANVICENTE-AÑORVE ◽  
MARGARITA HERMOSO-SALAZAR ◽  
AURORA MARRÓN-BECERRA
Keyword(s):  
Gulf Of Mexico ◽  
Monotypic Genus ◽  
Stages Of Development ◽  
Morphological Variations ◽  
Stages Of Growth ◽  
Early Stages ◽  
Southern Gulf Of Mexico ◽  
New Evidence ◽  
Lack Of Knowledge

Lack of knowledge of morphological variations during growth of amphipod crustaceans can result in misidentification of species. In this study, we advance the knowledge of morphological variations of juveniles of the monotypic genus Phrosina Risso, 1822 collected in the oceanic province of the southern Gulf of Mexico. The juveniles differed from the adults mainly in the morphology of pereopods 3 & 4 in that the carpal process is parallel to the propodus, also the rami of the pleopoda consist of only four segments, uropoda 3 are more lanceolate, and the uropoda bear a large prominent spine terminally. These morphological variations have not been described for the species previously. Therefore, the current observations enrich the description of P. semilunata in the early stages of growth and support the need for further taxonomical studiest that could help identify species at different stages of development.  

The first zoeal stage of the yellow land crab Johngarthia lagostoma (Milne Edwards, 1837) (Decapoda: Brachyura: Gecarcinidae)

Zootaxa ◽  
2021 ◽  
Vol 4990 (1) ◽  
pp. 192-200
Author(s):  
SIMONE MARIA DE ALBUQUERQUE LIRA ◽  
CYNTHIA DAYANNE MELLO DE LIMA ◽  
IGOR DE ÁVILA TEIXEIRA ◽  
RALF SCHWAMBORN
Keyword(s):  
Phylogenetic Relationships ◽  
Zoeal Stage ◽  
Dorsal Seta ◽  
Tropical Atlantic ◽  
Larval Morphology ◽  
Land Crab ◽  
The Family ◽  
Fernando De Noronha ◽  
Morphological Differences

The objective of this paper is to describe and illustrate the first zoeal stage of the largest land crab of the Tropical Atlantic, Johngarthia lagostoma (Milne Edwards, 1837) (Brachyura: Gecarcinidae). A larval description of J. lagostoma was previously not available. Larvae were obtained from ovigerous females on Rocas Atoll and Fernando de Noronha Archipelago, Brazil. Twenty larvae were randomly chosen to be dissected and described in detail, while 40 others (20 larvae from each island) were measured only. The published description of the congener J. planatus (Stimpson, 1860) larvae was used for a comparison of larval morphology. Some morphological differences between the first zoeal stage of these two species were: The absence or presence of a simple shorter seta on antennule, number of the minute terminal spines on the antenna, setation of the coxal endite of the maxilla, exopod unsegmented of the first and second maxilliped, and a single mid-dorsal seta on first pleonite. These results and differences observed between these species can assist in studies on phylogenetic relationships within the Family Gecarcinidae MacLeay, 1838, as well as in the identification of the larvae of J. Lagostoma in plankton samples from the tropical Atlantic.  

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