The exposed calcareous rocky area of the Abu Qir Headland,east of Alexandria,Egypt which range from coarse grains,through pebbles,cobbles,and boulders to rocky platforms,was signifi cantly colonized by sclerobionts(ep...The exposed calcareous rocky area of the Abu Qir Headland,east of Alexandria,Egypt which range from coarse grains,through pebbles,cobbles,and boulders to rocky platforms,was signifi cantly colonized by sclerobionts(epibionts and endobionts).The epibiont species diversity was comparatively higher than that of endobionts.Epibiont communities included bryozoans(the anascan-grade cheilostome Bifl ustra savartii),serpulid(Hydroides elegans,Spirobranchus cf.tetraceros,Vermiliopsis striaticeps and Protula or Apomatus)and spirorbid(Spirorbis)wormtubes,and balanoid barnacles(Amphibalanus amphitrite,Balanus trigonus,and Perforatus perforatus).The cheilostome bryozoan colonies,which developed extensive sheets,proliferated on the study rocky shore either encrusting the bioeroded basement directly,or encrusting other epilithic taxa,particularly balanoid barnacles and serpulid worms.Encrusters displayed a remarkable marginal competitive interaction(overgrowth and stand-off)for space on the study rocky shore.On the other hand,endobionts were not well represented on the studied rocky shore exposure.It was possible to identify three ichnotaxa:Gastrochaenolites,Maeandropolydora,and Finichnus.The fi ndings documented represent a signifi cant contribution to our knowledge of sclerobionts composition,sequence of their colonization and/or bioerosion,and their mutual relationships on the intertidal rocky shore of the Abu Qir Headland.展开更多
Seven Cornulites species,including a new one—Cornulites leonei n.sp.,are described from the Upper Ordovician Portixeddu Formation(Katian,stage slices Ka2-3)of Sardinia and the Cavá(lower Katian,stage slice Ka2)a...Seven Cornulites species,including a new one—Cornulites leonei n.sp.,are described from the Upper Ordovician Portixeddu Formation(Katian,stage slices Ka2-3)of Sardinia and the Cavá(lower Katian,stage slice Ka2)and Estana(upper Katian,stage slices Ka3-4)formations of the Pyrenees.The Sardinian and Pyrenean cornulitids represent an adaptation to live in environments with high sedimentation rates and limited hard substrates availability.Their prominent annuli could have had a stabilizing function in the soft sediment that helped cornulitids to keep a favourable position in the sediment to enable suspension feeding.The known Late Ordovician cornulitid diversity in different Gondwana areas is low,usually ranging from one to three taxa,being higher(seven)in Sardinia.Like other benthic groups during the Late Ordovician,the cornulitid tubeworm faunas within the high-latitude peri-Gondwana Province indicate a certain endemism and share morphological and ecological affinities,such as a small body size and tubes with a strikingly small apical angle.Although essentially endemic,some links with cornulitids from the Late Ordovician of Scotland are revealed.展开更多
基金Supported by the Researchers Supporting Project(No.RSP-2019/7),King Saud University。
文摘The exposed calcareous rocky area of the Abu Qir Headland,east of Alexandria,Egypt which range from coarse grains,through pebbles,cobbles,and boulders to rocky platforms,was signifi cantly colonized by sclerobionts(epibionts and endobionts).The epibiont species diversity was comparatively higher than that of endobionts.Epibiont communities included bryozoans(the anascan-grade cheilostome Bifl ustra savartii),serpulid(Hydroides elegans,Spirobranchus cf.tetraceros,Vermiliopsis striaticeps and Protula or Apomatus)and spirorbid(Spirorbis)wormtubes,and balanoid barnacles(Amphibalanus amphitrite,Balanus trigonus,and Perforatus perforatus).The cheilostome bryozoan colonies,which developed extensive sheets,proliferated on the study rocky shore either encrusting the bioeroded basement directly,or encrusting other epilithic taxa,particularly balanoid barnacles and serpulid worms.Encrusters displayed a remarkable marginal competitive interaction(overgrowth and stand-off)for space on the study rocky shore.On the other hand,endobionts were not well represented on the studied rocky shore exposure.It was possible to identify three ichnotaxa:Gastrochaenolites,Maeandropolydora,and Finichnus.The fi ndings documented represent a signifi cant contribution to our knowledge of sclerobionts composition,sequence of their colonization and/or bioerosion,and their mutual relationships on the intertidal rocky shore of the Abu Qir Headland.
基金The financial supported was provided by a Sepkoski Grant from the Paleontological SocietyKing Saud University,Riyadh,Saudi Arabia,Researchers Supporting Project Number RSP 2024R140Project PDI2021-125585NB-100 of the Spanish Ministry for Science Innovation (MICINN)。
文摘Seven Cornulites species,including a new one—Cornulites leonei n.sp.,are described from the Upper Ordovician Portixeddu Formation(Katian,stage slices Ka2-3)of Sardinia and the Cavá(lower Katian,stage slice Ka2)and Estana(upper Katian,stage slices Ka3-4)formations of the Pyrenees.The Sardinian and Pyrenean cornulitids represent an adaptation to live in environments with high sedimentation rates and limited hard substrates availability.Their prominent annuli could have had a stabilizing function in the soft sediment that helped cornulitids to keep a favourable position in the sediment to enable suspension feeding.The known Late Ordovician cornulitid diversity in different Gondwana areas is low,usually ranging from one to three taxa,being higher(seven)in Sardinia.Like other benthic groups during the Late Ordovician,the cornulitid tubeworm faunas within the high-latitude peri-Gondwana Province indicate a certain endemism and share morphological and ecological affinities,such as a small body size and tubes with a strikingly small apical angle.Although essentially endemic,some links with cornulitids from the Late Ordovician of Scotland are revealed.
