Phylogenetic constraints in the muscular system of rotifer males: investigation on the musculature of males versus females of Brachionus manjavacas and Epiphanes senta (Rotifera, Monogononta)
Articolo
Data di Pubblicazione:
2010
Citazione:
Phylogenetic constraints in the muscular system of rotifer males: investigation on the musculature of males versus females of Brachionus manjavacas and Epiphanes senta (Rotifera, Monogononta) / F. Leasi, D. Fontaneto, G. Melone. - In: JOURNAL OF ZOOLOGY. - ISSN 0952-8369. - 282:1(2010), pp. 109-119. [10.1111/j.1469-7998.2010.00721.x]
Abstract:
Sexual dimorphism is characteristic of monogonont rotifers, but at present, most
investigations on the evolution of morphology within Monogononta have focused
exclusively on females, with only minor taxonomic comments on the male
structure. Here, we make the first detailed comparison of female and male
morphology by examining their muscular organization, with the aim of understanding
how factors such as phylogeny, habitat and the structural rigidity of the
body wall determine the muscle arrangement patterns. We compare the musculature
of both females and males in Brachionus manjavacas and Epiphanes senta.
Generally, rotifer males have a similar ecology that may be different from the
conspecific females. Thus, we analysed muscles of conspecific females and males
with different ecology, namely habitat and/or different stiffness of the lorica.
Females of B. manjavacas are loricate and planktic, while E. senta females are
illoricate, can be found in the plankton, but have a lifestyle much related to a
substrate. Males are in both species free swimmers and without a stiff lorica.
Visceral muscles are present in the digestive (only in females) and reproductive
apparatus (only in males). Somatic musculature comprises inner longitudinal and
outer circular muscles. Major differences are discernible among circular muscle
states: B. manjavacas has dorsoventral bands, while E. senta possesses muscles that
are ventrally incomplete. The same condition occurs in both sexes. Results from
analyses on female rotifers support that the circular arrangement is a variable trait
that mainly reflects morpho-ecological adaptations, potentially related to the
development of a lorica. The presence of an identical condition in the conspecific
males, independently of their ecology, suggests, however, that this variability may
be limited by evolutionary and developmental constraints. Further investigations
should be required to clarify whether males have different arrangements from their
females, and thus whether their musculature may be informative for phylogeny
within monogononts.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
evolutionary ecology ; muscles ; Rotifera ; morphology ; confocal microscopy
Elenco autori:
F. Leasi, D. Fontaneto, G. Melone
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