Comparative morphology of the cottid genus Myoxocephalus based on meristic, morphometric, and other anatomical characters

1971 ◽  
Vol 49 (11) ◽  
pp. 1479-1496 ◽  
Author(s):  
Garry I. McT. Cowan
Keyword(s):  
Lateral Line ◽  
Gulf Of Alaska ◽  
Comparative Morphology ◽  
Distinct Species ◽  
Lateral Line System ◽  
Nominal Species ◽  
Meristic Characters ◽  
Important Species ◽  
Morphometric Characters ◽  
Line System

Specimens representing 15 nominal species of the genus Myoxocephalus were subjected to detailed comparative morphological study to determine some of the more important species characteristics and also those indicating potential for expressing phylogenetic progression.Analysis of seven meristic characters revealed that none of them is consistently sexually dependent. Geographic variation within the species indicated the presence of both latitudinal and longitudinal clines. No evolutionary group affinities were evident.The morphology of the cephalic lateral line system, lateral line ossicles, squamation, and olfactory rosettes were found to exhibit a high degree of specificity, especially the first three systems. With the exception of the lateral line ossicles all evidenced some potential as indicators of phylogeny.Analysis of 23 morphometric characters was accomplished by cluster analysis. The resultant clusters indicated heterogenous unnatural groupings.On the basis of these analyses well-defined species differences exist in most of the major morphological features. The nominal species M. scorpius (Linnaeus) includes three distinct species (Gulf of Alaska, Arctic–East coast, and European). In addition, the data indicate that the genus is probably composed of three basic evolutionary lines: the Holarctic–Atlantic, Bering Sea–Transpacific, and Asiatic.

A morphological comparison of two closely related species of the genus Myoxocephalus (Pisces: Cottidae) with notes on their life histories and ecology

1970 ◽  
Vol 48 (6) ◽  
pp. 1269-1281 ◽  
Author(s):  
Garry I. McT. Cowan
Keyword(s):  
Lateral Line ◽  
Life Histories ◽  
Species Recognition ◽  
Ecological Niches ◽  
Lateral Line System ◽  
Similar Species ◽  
Meristic Characters ◽  
Morphological Comparison ◽  
Morphometric Characters ◽  
Line System

Two closely related and superficially similar species of the genus Myoxocephalus (M. polyacanthocephalus and M. jaok) were subjected to critical morphological comparison with the hope of determining features through which speciation and divergence may have operated. Also, but to a lesser extent their ecology and life histories were studied.It was found that although the two species are sympatric over much of their ranges, they differ (whether as adults or juveniles) in their depth distributions.Major differences were detected in their general color patterns, degree of sexual dimorphism, and squamation; also in the morphology of the cephalic lateral line system, and of the lateral line ossicles. Six meristic characters were examined, all but one being found to show significant differences between the two species. Meristic variation proved greater in M. polyacanthocephalus than in M. jaok.Twenty-three morphometric characters were measured and analyzed for the two species. From this it was demonstrated that the selected structures of the two species grew differently in relation to one another. In general M. polyacanthocephalus grew more rapidly than did M. jaok.In a number of instances, the dissimilarities appeared to reflect differences in ecological niches between the two species. Other differences appeared to be of most significance in terms of mate selection and species recognition.

Comparative Morphology of the Mechanosensory Lateral Line System in a Clade of New Zealand Triplefin Fishes

2010 ◽  
Vol 75 (4) ◽  
pp. 292-308 ◽  
Author(s):  
Maren Wellenreuther ◽  
Michelle Brock ◽  
John Montgomery ◽  
Kendall D. Clements
Keyword(s):  
New Zealand ◽  
Lateral Line ◽  
Comparative Morphology ◽  
Lateral Line System ◽  
Line System

scholarly journals Frequency response properties of primary afferent neurons in the posterior lateral line system of larval zebrafish

2015 ◽  
Vol 113 (2) ◽  
pp. 657-668 ◽  
Author(s):  
Rafael Levi ◽  
Otar Akanyeti ◽  
Aleksander Ballo ◽  
James C. Liao
Keyword(s):  
Lateral Line ◽  
Sine Wave ◽  
Afferent Neuron ◽  
Lateral Line System ◽  
Afferent Neurons ◽  
Primary Afferent Neurons ◽  
Primary Afferent ◽  
Line System ◽  
Response Properties ◽  
Larval Zebrafish

The ability of fishes to detect water flow with the neuromasts of their lateral line system depends on the physiology of afferent neurons as well as the hydrodynamic environment. Using larval zebrafish ( Danio rerio), we measured the basic response properties of primary afferent neurons to mechanical deflections of individual superficial neuromasts. We used two types of stimulation protocols. First, we used sine wave stimulation to characterize the response properties of the afferent neurons. The average frequency-response curve was flat across stimulation frequencies between 0 and 100 Hz, matching the filtering properties of a displacement detector. Spike rate increased asymptotically with frequency, and phase locking was maximal between 10 and 60 Hz. Second, we used pulse train stimulation to analyze the maximum spike rate capabilities. We found that afferent neurons could generate up to 80 spikes/s and could follow a pulse train stimulation rate of up to 40 pulses/s in a reliable and precise manner. Both sine wave and pulse stimulation protocols indicate that an afferent neuron can maintain their evoked activity for longer durations at low stimulation frequencies than at high frequencies. We found one type of afferent neuron based on spontaneous activity patterns and discovered a correlation between the level of spontaneous and evoked activity. Overall, our results establish the baseline response properties of lateral line primary afferent neurons in larval zebrafish, which is a crucial step in understanding how vertebrate mechanoreceptive systems sense and subsequently process information from the environment.

scholarly journals Diversity and sexual dimorphism in the head lateral line system in North Sea populations of threespine sticklebacks, Gasterosteus aculeatus (Teleostei: Gasterosteidae)

Zoomorphology ◽  
2020 ◽  
Author(s):  
Harald Ahnelt ◽  
David Ramler ◽  
Maria Ø. Madsen ◽  
Lasse F. Jensen ◽  
Sonja Windhager
Keyword(s):  
Sexual Dimorphism ◽  
North Sea ◽  
Lateral Line ◽  
Gasterosteus Aculeatus ◽  
Sensory System ◽  
Threespine Stickleback ◽  
Lateral Line System ◽  
Line System ◽  
Marine Population ◽  
Threespine Sticklebacks

AbstractThe mechanosensory lateral line of fishes is a flow sensing system and supports a number of behaviors, e.g. prey detection, schooling or position holding in water currents. Differences in the neuromast pattern of this sensory system reflect adaptation to divergent ecological constraints. The threespine stickleback, Gasterosteus aculeatus, is known for its ecological plasticity resulting in three major ecotypes, a marine type, a migrating anadromous type and a resident freshwater type. We provide the first comparative study of the pattern of the head lateral line system of North Sea populations representing these three ecotypes including a brackish spawning population. We found no distinct difference in the pattern of the head lateral line system between the three ecotypes but significant differences in neuromast numbers. The anadromous and the brackish populations had distinctly less neuromasts than their freshwater and marine conspecifics. This difference in neuromast number between marine and anadromous threespine stickleback points to differences in swimming behavior. We also found sexual dimorphism in neuromast number with males having more neuromasts than females in the anadromous, brackish and the freshwater populations. But no such dimorphism occurred in the marine population. Our results suggest that the head lateral line of the three ecotypes is under divergent hydrodynamic constraints. Additionally, sexual dimorphism points to divergent niche partitioning of males and females in the anadromous and freshwater but not in the marine populations. Our findings imply careful sampling as an important prerequisite to discern especially between anadromous and marine threespine sticklebacks.

Larval lampreys possess a functional lateral line system

2006 ◽  
Vol 193 (2) ◽  
pp. 271-277 ◽  
Author(s):  
S. Gelman ◽  
A. Ayali ◽  
E. D. Tytell ◽  
A. H. Cohen
Keyword(s):  
Lateral Line ◽  
Lateral Line System ◽  
Line System
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