An attempt to differentiate sympatric Ichthyomyzon ammocoetes using meristic, morphological, pigmentation, and gonad analyses

2007 ◽  
Vol 85 (4) ◽  
pp. 549-560 ◽  
Author(s):  
F.B. Neave ◽  
N.E. Mandrak ◽  
M.F. Docker ◽  
D.L. Noakes
Keyword(s):  
Great Lakes ◽  
Genetic Markers ◽  
Intraspecific Variation ◽  
Lateral Line ◽  
Body Shape ◽  
Morphometric Characters ◽  
Brook Lamprey ◽  
Diagnostic Characters ◽  
Preliminary Classification

We assessed characters that could be used to differentiate ammocoetes of chestnut lamprey ( Ichthyomyzon castaneus Girard, 1858), northern brook lamprey ( Ichthyomyzon fossor Reighard and Cummins, 1916), and silver lamprey ( Ichthyomyzon unicuspis Hubbs and Trautman, 1937). We sampled ammocoetes of the three species from 25 streams around the Great Lakes. Existing genetic markers were used to identify chestnut lamprey for this study, but the lack of genetic markers for silver and northern brook lampreys forced our preliminary classification of these two species to be based on stream-specific catch records of adults. Comparison of ammocoete gonads was inconclusive as a technique to distinguish between these two species. Other characters examined (including pigmentation patterns, morphometric characters, body shape, and myomere counts) varied significantly among species, but were inadequate for use as diagnostic characters because of high intraspecific variation and overlapping ranges. Chestnut lamprey ammocoetes were sometimes distinguishable by their pigmented lateral line organs, but this character was not always apparent. The lack of distinguishing characteristics makes existing taxonomic keys misleading for identifying Ichthyomyzon lamprey larvae.

Classification of Sea Lamprey (Petromyzon marinus) Attack Marks on Great Lakes Lake Trout (Salvelinus namaycush)

1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
Author(s):  
Everett Louis King Jr.
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Petromyzon Marinus ◽  
Attachment Site ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Oral Disc ◽  
Field Assessment ◽  
Sea Lampreys

Criteria for the classification of marks inflicted by sea lamprey (Petromyzon marinus) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed.Key words: sea lamprey, attack marks, lake trout, Great Lakes

scholarly journals A new Silver Dollar species of Metynnis Cope, 1878 (Characiformes: Serrasalmidae) from Northwestern Brazil and Southern Venezuela

2016 ◽  
Vol 14 (4) ◽  
Author(s):  
Rafaela Priscila Ota ◽  
◽  
Lúcia Helena Rapp Py-Daniel ◽  
Michel Jégu ◽  
◽  
...  
Keyword(s):  
New Species ◽  
Lateral Line ◽  
Lower Limb ◽  
Body Shape ◽  
Color Pattern ◽  
High Concentration ◽  
Gill Rakers ◽  
Rio Negro ◽  
Silver Dollar ◽  
Rio Madeira

ABSTRACT A new Metynnis is described from the rio Negro in Brazil and Venezuela, and from black- or clearwater tributaries in Brazil including the rios Parauari, Uatumã, Trombetas, and Sucunduri (the latter belonging to the rio Madeira basin). The new species can be distinguished readily from all congeners by having a high concentration of dark chromatophores on the lateral line scales. It can be further distinguished by the combination of head length 24.3-27.5% of SL, 13-18 gill-rakers on upper limb and 16-24 gill-rakers on lower limb. The new species is most similar to and likely most closely related to Metynnis hypsauchen . These two species share a similar color pattern, body shape and sexual dimorphism of the anal fin. However, they differ in that M. hypsauchen has a lightly pigmented lateral line. The new species is also distinguished from M. hypsauchen by having 56-65 predorsal scales and 90-104 lateral line scales (vs . 36-54, and 65-82, respectively). A detailed osteological description of the new species is provided.

scholarly journals Rediscovering species: redescription of Bryconops gracilis (Characiformes: Iguanodectidae), an often-misidentified species

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Cárlison Silva-Oliveira ◽  
Rafaela P. Ota ◽  
Flávio C. T. Lima ◽  
Lúcia Rapp Py-Daniel
Keyword(s):  
Ct Scan ◽  
Distribution Pattern ◽  
Lateral Line ◽  
Body Shape ◽  
Color Pattern ◽  
Type Locality ◽  
Caudal Fin ◽  
Fin Rays ◽  
Pelvic Fin

ABSTRACT A redescription of Bryconops gracilis is provided, a species poorly known for more than a century. Bryconops gracilis differs from all congeners by having the following combination of features: eight branched pelvic-fin rays, 31-36 anal-fin rays, 15-17 predorsal scales arranged in a regular series, two rows of premaxillary teeth, and 53-60 lateral-line scales. The species was often misidentified as B. alburnoides by sharing an overall elongated body shape, caudal fin yellowish in life, and a high number of lateral-line scales. A diagnosis between B. alburnoides and B. gracilis is provided. The holotype of B. gracilis which for many years had whereabouts unknown, was recovered, examined and illustrated by CT-Scan. Additionally, more detailed information about the type locality, morphology, color pattern (including in living specimens), habitat and distribution pattern of species are provided.

scholarly journals Canine Malignant Mammary Tumours II. Adenocarcinomas, Solid Carcinomas and Spindle Cell Carcinomas

1972 ◽  
Vol 9 (6) ◽  
pp. 447-470 ◽  
Author(s):  
W. Misdorp ◽  
E. Cotchin ◽  
J. F. Hampe ◽  
Anne G. Jabara ◽  
J. von Sandersleben
Keyword(s):  
Spindle Cell ◽  
Clinical Signs ◽  
Subjective Assessment ◽  
Simple Type ◽  
Well Differentiated ◽  
The Times ◽  
Lymphatic Permeation ◽  
Preliminary Classification ◽  
Mammary Adenocarcinomas

A preliminary classification of 130 canine mammary adenocarcinomas, 76 solid carcinomas, and nine spindle cell carcinomas, together with several subtypes, was constructed from pooled, selected (metastasized) material. Each tumour in this series was classified by subjective assessment of its quantitatively predominant histological picture. Many adenocarcinomas and solid carcinomas of simple type were infiltrative, and lymphatic permeation was often found. The complex types of adenocarcinomas and of solid carcinomas were expansive, and lymphatic permeation was rare. Some metastasized adenocarcinomas were well differentiated. The clinical signs, distribution of metastases and some preliminary data on the times of survival of dogs with various types of carcinomas are discussed.

A Preliminary Classification of Usage Measures in Information System Acceptance

2013 ◽  
pp. 105-129 ◽  
Author(s):  
Muhammad Z. I. Lallmahomed ◽  
Nor Zairah Ab Rahim ◽  
Roliana Ibrahim ◽  
Azizah Abdul Rahman
Keyword(s):  
Information System ◽  
Technology Acceptance ◽  
Rater Agreement ◽  
Dimensional Measure ◽  
System Use ◽  
System Acceptance ◽  
Acceptance Model ◽  
Q Sort ◽  
Preliminary Classification

In the light of a diverse body of disorganized usage measures available and the difficulty of building a cumulative research tradition, a literature review is conducted on system use in Information Systems (IS) Acceptance through the two main theories of Technology Adoption, the Technology Acceptance Model (TAM), and The Unified Theory of Use and Acceptance of Technology (UTAUT). The authors seek to understand how usage measures are being operationalised and proposed a preliminary classification of those measures that covers system and task aspects of use. A Q-Sort approach was taken to validate the authors’ classification scheme and the result indicates high inter-rater agreement. The ensuing classification is meant to help researchers in their choice of system use measures. This review also summarises the arguments for a multi-dimensional measure of use and establishes that omnibus measure such as frequency, volume and use/non-use hold prevalence. Finally, the authors provide recommendations for further research in the area of system use.

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