Trunk spines in cystacanths and adults of Corynosoma spp. (Acanthocephala): Corynosoma cetaceum as an exceptional case of phenotypic variability
Por:
Aznar, Francisco J., Crespo, Enrique A., Raga, Juan A., Hernandez-Orts, Jesus S.
Publicada:
1 mar 2016
Resumen:
Adults of the acanthocephalan Corynosoma cetaceum deeply attach to the
stomach of dolphins using the proboscis and its spiny foretrunk as a
disk while the spiny hindtrunk bends to also embed its ventral spines.
During deep attachment, two ventral folds of tegument, anterior and
posterior, are created. Spine growth is inhibited to a variable degree
in folds, generating an extraordinary phenotypic variability, with most
individuals, especially females, having folds partially or totally
devoid of spines. Little is known on how this variability is generated
and why it is not apparently found in other Corynosoma spp. In this
paper, we examined the trunk armature of 77 and 388 cystacanth larvae of
C. cetaceum and C. australe, respectively, from teleosts, and over 8800
adult specimens of C. australe, C. bullosum, C. cetaceum, C. strumosum,
C. villosum and C. wegeneri from marine mammals. Cystacanths and adults
of C. cetaceum exhibited the same range of fold spine reduction and
variability, suggesting that they are generated prior to the adult stage
(i.e., before spines are functional) and do not result from phenotypic
plasticity. The other Corynosoma species analyzed created only the
anterior fold during deep attachment, but it was always spined. Females
of C. cetaceum had significantly larger foretrunk and hindtrunk spines
than the other species and likely suffer stronger fold compression
during deep attachment. The exceptional colonization of a harsh
microhabitat, the stomach, could have generated a trade-off in C.
cetaceum, which must bend the trunk to attach (as other Corynosoma spp.)
but must also produce large spines that, in the folds, presumably are
maladaptive and must be reduced.
Filiaciones:
Aznar, Francisco J.:
Univ Valencia, Inst Cavanilles Biodiversidad & Biol Evolut, Parque Cient,C Catedrat Jose Beltran 2, Valencia 46980, Spain
Crespo, Enrique A.:
Consejo Nacl Invest Cient & Tecn, Ctr Nacl Patagon, Lab Mamiferos Marinos, Blvd Brown 2915, RA-9120 Puerto Madryn, Chubut, Argentina
Univ Patagonia, Blvd Brown 2915, RA-9120 Puerto Madryn, Chubut, Argentina
Raga, Juan A.:
Univ Valencia, Inst Cavanilles Biodiversidad & Biol Evolut, Parque Cient,C Catedrat Jose Beltran 2, Valencia 46980, Spain
Hernandez-Orts, Jesus S.:
Univ Nacl Autonoma Mexico, Dept Zool, Inst Biol, Ave Univ 3000,Ciudad Univ, Mexico City 04510, DF, Mexico
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