Structure and occurrence of cyphonautes larvae (Bryozoa, Ectoprocta)
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Structure and occurrence of cyphonautes larvae (Bryozoa, Ectoprocta). / Nielsen, Claus; Worsaae, Katrine.
In: Journal of Morphology, Vol. 271, No. 9, 2010, p. 1094-1109.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Structure and occurrence of cyphonautes larvae (Bryozoa, Ectoprocta)
AU - Nielsen, Claus
AU - Worsaae, Katrine
PY - 2010
Y1 - 2010
N2 - We have studied larvae of the freshwater ctenostome Hislopia malayensis with scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and LM of serial sections. Some additional observations on larvae of M. membranacea using SEM and CLSM are also reported. The overall configuration of muscles, nerves, and cilia of the two larvae are identical. However, the larva of H. malayensis is much smaller than that of M. membranacea, which may explain most of the differences observed. Although all major nerves and muscle strands are present in H. malayensis, they are generally composed of fewer fibers. The H. malayensis larva lacks the anterior and posterior intervalve cilia. Its pyriform organ is unciliated with only a small central depression. The adhesive epithelium is not invaginated as an adhesive sac and lacks the large muscles interpreted as adhesive sac muscles in the M. membranacea larva. The velum carries two rows of ciliated cells, though the lower "row" consists of only one or two cells. Both rows of ciliated cells are innervated by nerves, which have not been detected in the M. membranacea larva. The ciliated ridge of H. malayensis lacks the frontal cilia. The planktotrophic cyphonautes larvae in a number of ctenostome clades and in the "basal" cheilostome clade Malacostega (and probably in the earliest cheilostomes) support the idea that the cyphonautes larva is the ancestral larval type of the Eurystomata. It may even represent the ancestral larval type of the bryozoans (= ectoprocts).
AB - We have studied larvae of the freshwater ctenostome Hislopia malayensis with scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and LM of serial sections. Some additional observations on larvae of M. membranacea using SEM and CLSM are also reported. The overall configuration of muscles, nerves, and cilia of the two larvae are identical. However, the larva of H. malayensis is much smaller than that of M. membranacea, which may explain most of the differences observed. Although all major nerves and muscle strands are present in H. malayensis, they are generally composed of fewer fibers. The H. malayensis larva lacks the anterior and posterior intervalve cilia. Its pyriform organ is unciliated with only a small central depression. The adhesive epithelium is not invaginated as an adhesive sac and lacks the large muscles interpreted as adhesive sac muscles in the M. membranacea larva. The velum carries two rows of ciliated cells, though the lower "row" consists of only one or two cells. Both rows of ciliated cells are innervated by nerves, which have not been detected in the M. membranacea larva. The ciliated ridge of H. malayensis lacks the frontal cilia. The planktotrophic cyphonautes larvae in a number of ctenostome clades and in the "basal" cheilostome clade Malacostega (and probably in the earliest cheilostomes) support the idea that the cyphonautes larva is the ancestral larval type of the Eurystomata. It may even represent the ancestral larval type of the bryozoans (= ectoprocts).
KW - Faculty of Science
KW - evolution; immunohistochemistry; CLSM; SEM; morphology
KW - KeyWords Plus: CILIARY FEEDING MECHANISM; MEMBRANIPORA-MEMBRANACEA; NERVOUS-SYSTEM; POLYZOA; CHEILOSTOMATA; EVOLUTIONARY; MUSCULATURE; MORPHOLOGY; PHYLOGENY; IDENTITY
U2 - 10.1002/jmor.10856
DO - 10.1002/jmor.10856
M3 - Journal article
C2 - 20730922
VL - 271
SP - 1094
EP - 1109
JO - Journal of Morphology
JF - Journal of Morphology
SN - 0362-2525
IS - 9
ER -
ID: 18046744