Internal anatomy of the polybranchiaspids (Agnatha, Galeaspida)

Nature ◽  
1979 ◽  
Vol 282 (5741) ◽  
pp. 833-836 ◽  
Author(s):  
L. B. Halstead
Keyword(s):  
Internal Anatomy

scholarly journals Using micro-computed tomography to reveal the anatomy of adult Diaphorina citri Kuwayama (Insecta: Hemiptera, Liviidae) and how it pierces and feeds within a citrus leaf

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Javier Alba-Tercedor ◽  
Wayne B. Hunter ◽  
Ignacio Alba-Alejandre
Keyword(s):  
Computed Tomography ◽  
Significant Advance ◽  
Micro Ct ◽  
Diaphorina Citri ◽  
Ct Reconstruction ◽  
Internal Anatomy ◽  
Micro Computed Tomography ◽  
Citrus Leaf ◽  
Teaching Aids ◽  
Adult Feeding

AbstractThe Asian citrus psyllid (ACP), Diaphorina citri, is a harmful pest of citrus trees that transmits Candidatus Liberibacter spp. which causes Huanglongbing (HLB) (citrus greening disease); this is considered to be the most serious bacterial disease of citrus plants. Here we detail an anatomical study of the external and internal anatomy (excluding the reproductive system) using micro-computed tomography (micro-CT). This is the first complete 3D micro-CT reconstruction of the anatomy of a psylloid insect and includes a 3D reconstruction of an adult feeding on a citrus leaf that can be used on mobile devices. Detailed rendered images and videos support first descriptions of coxal and scapus antennal glands and sexual differences in the internal anatomy (hindgut rectum, mesothoracic ganglion and brain). This represents a significant advance in our knowledge of ACP anatomy, and of psyllids in general. Together the images, videos and 3D model constitute a unique anatomical atlas and are useful tools for future research and as teaching aids.

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.

scholarly journals Redescription of Ochmacanthus batrachostoma (Miranda-Ribeiro, 1912) (Siluriformes: Trichomycteridae): a possible case of incipient paedomorphism

2016 ◽  
Vol 14 (1) ◽  
Author(s):  
Caio S. Neto ◽  
Mário de Pinna
Keyword(s):  
Body Size ◽  
Internal Anatomy ◽  
Morphometric Traits ◽  
Type Specimens ◽  
Caudal Peduncle ◽  
Caudal Fin ◽  
Maximum Body ◽  
Maximum Body Size

ABSTRACT The lepidophagous stegophiline catfish Ochmacanthus batrachostoma (Miranda-Ribeiro, 1912) is endemic to the Paraná-Paraguai basin and is the only member of its genus in that drainage. It remains a poorly-known taxon mainly due to the historical scarcity of study specimens. The species is herein redescribed on the basis of type and non-type specimens from Brazil, Argentina and Paraguay. Ochmacanthus batrachostoma can be distinguished from congeners by the presence of long maxillary and rictal barbels, reduction of the posterior end of the caudal peduncle, a tadpole-like caudal fin and peduncle, among other morphometric traits and features of internal anatomy. Comparisons show that a number of unique traits of adult O. batrachostoma resemble conditions seen in juvenile specimens of other members of Stegophilinae. Such traits are also more pronounced in juveniles of O. batrachostoma itself. The species also has the smallest maximum body size in Ochmacanthus and among the smallest of any stegophiline. In combination, such observations suggest that the species is paedomorphic, although to a degree less extreme than seen in some other trichomycterids. This is the first possible case of paedomorphosis identified for stegophilines.

Articulated halkieriids from the Lower Cambrian of North Greenland and their role in early protostome evolution

1995 ◽  
Vol 347 (1321) ◽  
pp. 305-358 ◽  
Keyword(s):  
Body Size ◽  
Molecular Biology ◽  
Lower Cambrian ◽  
Burgess Shale ◽  
Internal Anatomy ◽  
Middle Cambrian ◽  
Functional Consequence ◽  
Primitive State ◽  
North Greenland

Articulated halkieriids of Halkieria evangelista sp. nov. are described from the Sirius Passet fauna in the Lower Cambrian Buen Formation of Peary Land, North Greenland. Three zones of sclerites are recognizable: obliquely inclined rows of dorsal palmates, quincuncially inserted lateral cultrates and imbricated bundles of ventro-lateral siculates. In addition there is a prominent shell at both ends, each with radial ornamentation. Both sclerites and shells were probably calcareous, but increase in body size led to insertion of additional sclerites but marginal accretion of the shells. The ventral sole was soft and, in life, presumably muscular. Recognizable features of internal anatomy include a gut trace and possible musculature, inferred from imprints on the interior of the anterior shell. Halkieriids are closely related to the Middle Cambrian Wixaxia , best known from the Burgess Shale: this clade appears to have played an important role in early protostome evolution. From an animal fairly closely related to Wixaxia arose the polychaete annelids; the bundles of siculate sclerites prefigure the neurochaetae whereas the dorsal notochaetae derive from the palmates. Wixaxia appears to have a relic shell and a similar structure in the sternaspid polychaetes may be an evolutionary remnant. The primitive state in extant polychaetes is best expressed in groups such as chrysopetalids, aphroditaceans and amphinomids. The homology between polychaete chaetae and the mantle setae of brachiopods is one line of evidence to suggest that the latter phylum arose from a juvenile halkieriid in which the posterior shell was first in juxtaposition to the anterior and rotated beneath it to provide the bivalved condition of an ancestral brachiopod. H. evangelista sp. nov. has shells which resemble those of a brachiopod; in particular the posterior one. From predecessors of the halkieriids known as siphogonuchitids it is possible that both chitons (polyplacophorans) and conchiferan molluscs arose. The hypothesis of halkieriids and their relatives having a key role in annelid—brachiopod—mollusc evolution is in accord with some earlier proposals and recent evidence from molecular biology. It casts doubt, however, on a number of favoured concepts including the primitive annelid being oligochaetoid and a burrower, the brachiopods being deuterostomes and the coelom being an archaic feature of metazoans. Rather, the annelid coelom arose as a functional consequence of the transition from a creeping halkieriid to a polychaete with stepping parapodial locomotion.

scholarly journals Three new species of Scissurellidae (Gastropoda, Prosobranchia) from the coast of Brazil

1972 ◽  
Vol 21 (0) ◽  
pp. 01-13 ◽  
Author(s):  
Pierre Ch. Montouchet
Keyword(s):  
New Species ◽  
Sao Paulo ◽  
The State ◽  
Shallow Waters ◽  
Brazilian Coast ◽  
São Paulo ◽  
Internal Anatomy ◽  
The Third ◽  
Deep Waters ◽  
Three New Species

A consultation of the original descriptions of the genera of Scissurellidae led the author to conclude that the valid names for the genera of this family are: Scissurella d'Orbigny, 1823 (redescription by Sowerby, 1824), Anatoma Woodward, 1859, Inoisura Hedley, 1904, Scissurona Iredale, 1924, Sinezona Finlay, 1927. Scissurella and Anatoma are cosmopolites, the first generally living in shallow waters, associated to sea-weeds, while the second is found in deep waters. The three last genera are restricted to Australasia. Three new species are described from the Brazilian coast: Soissu rella alexandrei, Scissurella eleotilis and Scissurella morretesi. The internal anatomy of S. alexandrei is described. These three new species have been found in littoral shallow waters, the two first on the northeast Brazilian coast, the third on the coast of the State of São Paulo. The fourth known species of Scissurellidae from Brazil, Anatoma aedonia (Watson, 1886), was dredged by H.M.S, "Challenger", in 1873, off Pernambuco, 350 fm (640 m).

Internal anatomy ofHaliclystus antarcticus(Cnidaria, Staurozoa) with a discussion on histological features used in staurozoan taxonomy

2013 ◽  
Vol 274 (12) ◽  
pp. 1365-1383 ◽  
Author(s):  
Lucília S. Miranda ◽  
Allen G. Collins ◽  
Antonio C. Marques
Keyword(s):  
Internal Anatomy ◽  
Histological Features

Testing evolutionary constraint hypotheses with early Paleozoic gastropods

Paleobiology ◽  
1995 ◽  
Vol 21 (3) ◽  
pp. 248-272 ◽  
Author(s):  
Peter J. Wagner
Keyword(s):  
Shell Morphology ◽  
Sister Species ◽  
Evolutionary Constraint ◽  
Early Paleozoic ◽  
Internal Anatomy ◽  
Morphometric Characters ◽  
Higher Taxa ◽  
Phylogenetic Constraints ◽  
And Function ◽  
Over Time

The evolution of higher taxa among early Paleozoic gastropods is similar to that among early metazoans as a whole, as higher taxa diversified rapidly and early. There are two issues pertinent to this pattern. First, were greater morphologic changes concentrated in the early phases of evolution? Second, does the pattern better fit models of increasing phylogenetic constraints or increasing ecologic restrictions? This paper presents a phylogeny-based method designed to test whether amounts of morphologic evolution decreased over time. It also explores whether the data better fits models of increasing phylogenetic (i.e., developmental or genetic) constraint or increasing ecologic restriction. Two metrics of morphologic separation (i.e., the morphologic difference between sister-species) are used: (1) Euclidean distance in morphospace and (2) transition magnitude. The latter metric is calculated by a multivariate analysis of sister-species contrasts, which determines both types and magnitudes of morphologic transitions. The advantage of using transition magnitudes is that it balances the effects of transitions that either affect more morphometric characters or occur more frequently. Both metrics indicate that larger morphologic separations between sister-species were concentrated early in gastropod evolution. Among gastropods, gross shell morphology often reflects basic trophic strategy and function whereas basic internal anatomy does not. Transition magnitudes can be broken down into transitions associated with differences in basic trophic strategies and shell functional biology (“external”), and those associated with differences in basic internal anatomy (“internal”). Internal transition magnitudes show a highly significant decrease over time (p < 10–04) whereas external transition magnitudes show a much less significant decrease over time (p < 0.10) and no significant decrease after the earliest Ordovician (p ≅ 0.50). The results therefore suggest that increasing phylogenetic constraints played a greater role in the early evolution of gastropods than did increasing ecologic ones.

scholarly journals Cone beam-computed tomography as an indispensable tool in the management of radiculous premolar: a case report

2016 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Shristhi Sharma ◽  
Ananth Raghav Sharma ◽  
Vivek Kumar Rai ◽  
Ronak Choudhary
Keyword(s):  
Computed Tomography ◽  
Case Report ◽  
Cone Beam Computed Tomography ◽  
Anatomical Variations ◽  
Endodontic Treatment ◽  
Cone Beam ◽  
Internal Anatomy ◽  
Indispensable Tool ◽  
Rule Out

Background: Internal anatomy of maxillary first premolars is particularly multifaceted on account of the variation in number of roots and canal configuration. Maxillary first premolars with 3 roots are called as small molar or “radiculous” because of their similar anatomy to the maxillary first molars. The most demanding step in endodontic treatment is identification and proper access to pulp canals of certain teeth with atypical canal configurations. Methods of identification of such premolars can be by various aides.Case Presentation: The present case describes the application of Cone Beam-Computed Tomography in the diagnosis of extra root with extra canal in a three rooted maxillary right first premolar.Conclusions: Proper knowledge of the anatomical variations is a must for an endodontist to make a treatment successful. Utilizing the latest technology along with the traditional concepts can surely rule out the inaccuracy in the treatment involved in such cases.

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