Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Evolution of cave suspension feeding in Protodrilidae (Annelida) |
| Abstract | Protodrilidae belongs in a lineage that until now entirely consisted of deposit-feeding, highly adapted interstitial annelids. Except for a pair of anterior palps, all protodrilids lack appendages, parapodia and chaetae; and have slender bodies adapted to glide between the sand grains by ciliary motion. The first exception to these characteristics is Megadrilus pelagicus n. sp. inhabiting the water column of the anchialine La Corona cave system in Lanzarote. Its morphology and evolutionary history are here investigated by combining observations from in vivo video recordings and advanced microscopy with phylogenetic analyses. Our studies revealed a unique pelagic, suspension feeding behaviour attained by its long ciliated palps in combination with an autopomorphic dorsal ciliated keel and several longitudinal and transverse ciliary bands. Phylogenetic analyses recovered Megadrilus pelagicus n. sp. nested within Protodrilidae indicating that its unique traits are derived within the family. These traits are traced in the tree topologies in correlation to cave colonization. The evolution of these traits can be functionally explained by the different demands of a pelagic suspension feeding strategy compared to the ancestral deposit-feeding guild of the family. The origin of this suspension feeding strategy was presumably favoured by the partial isolation of the anchialine ecosystem, connected to the sea only through the highly porous volcanic subterranean bedrock. This crevicular connection limits the amount of predators and turbulence in the cave, but allows continuous water flow into the system carrying organic particles, which is the main source of food when photosynthetic primary production does not occur and sedimentation is limited. These conditions may select for pelagic suspension feeding as the most feasible life-strategy in anchialine caves, which the dominance of pelagic, suspension feeding crustaceans and annelids in anchialine cave assemblages may also reflect. For species of ancestrally deposit-feeding lineages entering the cave system, such as the annelid families Protodrilidae and Nerillidae, an adaptive-shift from interstitial to crevicular habitats seemingly correlates with dramatic morphological changes and speciation. The dramatic changes observed in these primarily interstitial lineages compared to their relatives, point to alternative adaptive evolutionary pathways related to ecological fitness contrary to the previously proposed theories focusing on geological or stochastic processes. |
| Source | Zoologica scripta (Online) 46 (2), pp. 214–226 |
| Keywords | Protodrilidaecave |
| Journal | Zoologica scripta (Online) |
| Editor | Blackwell, Oxford, Regno Unito |
| Year | 2017 |
| Type | Articolo in rivista |
| DOI | 10.1111/zsc.12198 |
| Authors | Martinez A.; Kvindebjerg K.; Iliffe T.M.; Worsaae K. |
| Text | 382546 2017 10.1111/zsc.12198 Scopus 2 s2.0 84982239343 ISI Web of Science WOS 000395084200008 Protodrilidae cave Evolution of cave suspension feeding in Protodrilidae Annelida Martinez A.; Kvindebjerg K.; Iliffe T.M.; Worsaae K. Marine Biological Section, University of Copenhagen, Universitetsparken 4, Copenhagen, DK 2100, , Denmark; Department of Marine Biology, Texas A M University at Galveston, Galveston, TX, 77553 1675, , United States Protodrilidae belongs in a lineage that until now entirely consisted of deposit feeding, highly adapted interstitial annelids. Except for a pair of anterior palps, all protodrilids lack appendages, parapodia and chaetae; and have slender bodies adapted to glide between the sand grains by ciliary motion. The first exception to these characteristics is Megadrilus pelagicus n. sp. inhabiting the water column of the anchialine La Corona cave system in Lanzarote. Its morphology and evolutionary history are here investigated by combining observations from in vivo video recordings and advanced microscopy with phylogenetic analyses. Our studies revealed a unique pelagic, suspension feeding behaviour attained by its long ciliated palps in combination with an autopomorphic dorsal ciliated keel and several longitudinal and transverse ciliary bands. Phylogenetic analyses recovered Megadrilus pelagicus n. sp. nested within Protodrilidae indicating that its unique traits are derived within the family. These traits are traced in the tree topologies in correlation to cave colonization. The evolution of these traits can be functionally explained by the different demands of a pelagic suspension feeding strategy compared to the ancestral deposit feeding guild of the family. The origin of this suspension feeding strategy was presumably favoured by the partial isolation of the anchialine ecosystem, connected to the sea only through the highly porous volcanic subterranean bedrock. This crevicular connection limits the amount of predators and turbulence in the cave, but allows continuous water flow into the system carrying organic particles, which is the main source of food when photosynthetic primary production does not occur and sedimentation is limited. These conditions may select for pelagic suspension feeding as the most feasible life strategy in anchialine caves, which the dominance of pelagic, suspension feeding crustaceans and annelids in anchialine cave assemblages may also reflect. For species of ancestrally deposit feeding lineages entering the cave system, such as the annelid families Protodrilidae and Nerillidae, an adaptive shift from interstitial to crevicular habitats seemingly correlates with dramatic morphological changes and speciation. The dramatic changes observed in these primarily interstitial lineages compared to their relatives, point to alternative adaptive evolutionary pathways related to ecological fitness contrary to the previously proposed theories focusing on geological or stochastic processes. 46 Published version http //www.scopus.com/inward/record.url eid=2 s2.0 84982239343 partnerID=q2rCbXpz Articolo 2017_zoologiac_scripta_46_2_214_226.pdf Articolo in rivista Blackwell 1463 6409 Zoologica scripta Online Zoologica scripta Online Zool. scr. Online Zoologica scripta Online alejandro.martinezgarcia MARTINEZ GARCIA ALEJANDRO |