Adriaens, Dominique

De Schepper, Natalie

Dumont, Elisabeth

Herrel, Anthony

Ide, Celine

Ghent University Academic Bibliography

Divergent head shape variation in European eel: how well does skeletal morphology reflect functional demands?

Ide, C.

De Schepper, N.

Dumont, B.

Herrel, A.

Adriaens, D.

Open Marine Archive

47.4 HUYGHE, K.*; HUSAK, J.F.; VANHOOYDONCK, B.; HERREL, A.;
MOORE, I.T.; VAN DAMME, R.; University of Antwerp, Belgium, Virginia
Tech University, Harvard University; katleen.huyghe@ua.ac.be
Testosterone and performance in a population of color polymorphic
lizards
Through their direct action on behavior or through their influence on
morphology and performance, circulating testosterone levels can be
mediators of aggressive displays and interactions. We tested these ideas in
a population of l izards, which exhibits a distinct and striking color
polymorphism. Males occur in 3 different colors (white, yellow, orange),
providing an opportunity to test the idea that morphs are alternative solutions
to the evolutionary challenges posed on the link between hormones,
morphology, performance, and behavior. Our results show that morphs differ
in size, and bite force capacity, but do not differ in locomotor performance.
Here, we provide data to test the hypothesis that these differences are
related to differences in steroid hormone levels between morphs, suggesting
a balance between different fitness effects. Secondly, we test for the
presence of a correlation between testosterone and different performance
traits, as organismal performance can be expected to be important in
mediating the outcome of aggressive male-male interactions and may play a
role in female choice.
S2.9 HUYS, R*; LLEWELLYN-HUGHES, J; British Museum;
r.huys@nhm.ac.uk
What can 18S rDNA do for copepod phylogeny and classification?
No group of plants or animals on Earth exhibits the range of morphological
diversity as seen among the extant Crustacea. This is best demonstrated by
the Copepoda, which by virtue of their immense vertical distribution are also
arguably the most abundant metazoans. Their current position of world
predominance can be attributed to two principal, recurrent, radiation events,
i.e. their major habitat shift into the marine plankton, and the evolution of
parasitism. Given their moderately high host specificity in conjunction with
the incredible spectrum of potential marine hosts, it is highly conceivable that
parasitic copepods significantly outnumber their free-living counterparts in
species diversity. Their successful colonization or utilization of virtually every
metazoan phylum has generated a great diversity in copepod body
morphology, which is arguably unparalleled among the Crustacea. Families
such as the Monstril l idae and Thaumatopsyllidae demonstrate how
extremely powerful natural selection can be in shaping morphology to meet
functional needs so that distantly related taxa may appear uncannily similar.
Here I will show how small subunit ribosomal sequence data (18S rDNA) can
help resolving controversial issues that had reached a temporary impasse in
the phylogeny and classification of the symbiotic copepods, such as the
placement of the Thaumatopsyllidae, the paraphyly of the Cyclopoida and
the origin of parasitism in freshwater. I will demonstrate how the use of such
data can lead to the discovery of previously overlooked morphological
characters and how they impact on the ordinal level classification of the
Copepoda.
97.10 HYNDMAN, K/A*; EDWARDS, S/L; KRATOCHVILOVA, H;
CLAIBOREN, J/B; EVANS, D/H; Medical College of Georgia, Vascular
Biology Center, Augusta GA, Appalachian State University, Boone NC,
Georgia Southern University, Statesboro GA, Georgia Southern University,
Statesboro GA, University of Florida, Gainesville FL ; khyndman@ufl.edu
The effect of short-term, low-salinity acclimation on gill NHE, AE1 and
HAT expression in the longhorn sculpin, Myoxocephalus
octodecemspinosus,.
We previously reported that the marine, longhorn sculpin, Myoxocephalus
octodecemspinosus, can acclimate to 20% SW for days with no change in
plasma osmolality, ion concentrations, or hematocrit level. Sculpin, however,
lose ions during acclimation to 10% SW for 24 and 72 h and this reaches a
lethal level after 6 days. During these acclimations, the sculpin is incapable
of down-regulating gill NKCC or CFTR, suggesting that they cannot turn off
their gill ion secreting mechanisms. The counterpart to this is whether they
can upregulate the transporters necessary for ion uptake during acclimation
to low salinity water, such as the Na+/H+ exchangers (NHE), anion
exchanger 1 (AE1) or H+-ATPase (HAT), and thus maintain proper ion and
water balance. We determined that sculpin upregulate gill NHE3 mRNA and
NHE2c, while significantly down regulating AE1 during acclimation to 20%
SW, and have undetectable levels of NHE2b during acclimation to 10% SW.
There were no significant changes in HAT or NHE8. These transporters were
immunolocalized in the sculpin gil l, and we determined that during
acclimation to 10 or 20% SW they are distributed in different aspects of the
ion transporting cells of the gill. Thus, we conclude that longhorn sculpin are
incapable of properly regulating gill ion transporters; thus, this is a
physiological barrier from living in low-salinity (below 10% SW) or fresh
water.
25.6 IDE, Celine*; DE SCHEPPER, Natalie; DUMONT, Betsy; HERREL,
Anthony; ADRIAENS, Dominique; Ghent University; celine.ide@ugent.be
Divergent head shape variation in European eel: how well does skeletal
morphology reflect functional demands?
The existence of naturally occurring narrow- and broad-headed individuals
within the European eel (Anguilla anguilla) populations is since long known.
Previous studies demonstrated sexual differences in growth, with females
growing faster than males, but which is irrespective of the observed
difference in head shape. The apparent divergent head shapes have been
related to differences in the diet, where broad-headed eels would feed on
bigger and harder prey items. Although some research has been focusing on
this dimorphism, very l i t t le is sti l l  known about how and when this
dimorphism arises and what parts of the body plan are involved. What has
already been observed is that broad-headed types have larger jaw muscles
than narrow-headed ones, where modeling of bite-force suggested higher
bite force in broad-headed once. Whether differences observed between the
two morphotypes at the skeletal level is a reflection of dealing with
differences in mechanical stress during prey manipulation still remains
unclear. Using Finite Element Analysis we thus wanted to see to what
degree differences in skull morphology between narrow- and a broad-headed
eels have an effect on stress distribution when a force is being applied. With
this analysis we wanted to find out if the skull architecture in broad-headed
eels allows dealing with higher biting forces, and hence is more resistant to
mechanical loading force when feeding on harder prey items.
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Divergent head shape variation in European eel: how well does skeletal morphology reflect functional demands?

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