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Diverse early endobiotic coral symbiont assemblage from the Katian (Late Ordovician) of Baltica
Abstract
A diverse early endobiotic coral symbiont assemblage has been detected
within heliolitid tabulate corals of Katian age from northwestern
Estonia. This assemblage indicates that the earliest endobiotic coral
symbiont communities were not restricted to North America. The symbiotic
endobiont assemblage comprises abundant Cornulites aff. celatus and rare
Conchicolites hosholmensis and Chaetosalpinx sp. The cornulitids are the
earliest known symbiotic endobionts of this group. The symbiotic
endobionts presumably occurred in certain hosts only and preferred
Protoheliolites dubius over Propora speciosa. This record indicates that
early endobiotic cornulitids were more diverse than previously thought
and appeared in large numbers in the Katian. It is possible that the
appearance of abundant skeletal symbiotic coral endobionts may coincide
with the Global Ordovician Biodiversification Event, supporting the
hypothesis of escape from increased predation.
... Late Ordovician bioclaustrations left by probable parasites are common in bryozoans both in Baltica and Laurentia (Palmer and Wilson, 1988;Vinn et al., 2014Vinn et al., , 2018. The cornulitids often formed symbiotic associations with other invertebrates in the Late Ordovician of Baltica (Vinn and Mõtus, 2012;Vinn, 2013) and Laurentia (Dixon, 2010). Chaetosalpinx is a common bioclaustration ichnogenus that has been reported from Late Ordovician corals of Laurentia (Elias, 1986;Tapanila, 2003Tapanila, , 2004Tapanila, , 2005 and Baltica (Vinn and Mõtus, 2012). ...
... The cornulitids often formed symbiotic associations with other invertebrates in the Late Ordovician of Baltica (Vinn and Mõtus, 2012;Vinn, 2013) and Laurentia (Dixon, 2010). Chaetosalpinx is a common bioclaustration ichnogenus that has been reported from Late Ordovician corals of Laurentia (Elias, 1986;Tapanila, 2003Tapanila, , 2004Tapanila, , 2005 and Baltica (Vinn and Mõtus, 2012). The Chaetosalpinx bioclaustrations have been studied at least since Oekentorp (1969) and more recently by Tapanila (2003Tapanila ( , 2004Tapanila ( , 2005 and Zapalski (2008Zapalski ( , 2009. ...
... In a number of papers (Vinn and Mõtus, 2012;Vinn, 2013;Toom et al. 2019), symbiotic interactions involving corals have been described from the Katian of Estonia, but all these associations were found from the Pirgu Regional Stage, which is younger than materials from the Vormsi Regional Stage described here for the first time. In addition, all symbiotic associations involving lingulids, stromatoporoids and bryozoans that are described here are new for the late Katian of Estonia and Baltica. ...
Endobiotic cornulitids formed symbiotic associations with tabulate corals and stromatoporoids in the Katian (Late Ordovician) of Estonia. The cornulitids benefited from
a stable substrate and additional protection against predators offered by the skeleton
of their hosts. Symbiotic lingulates and Chaetosalpinx-like bioclaustration structures
are here reported from bryozoans for the first time. The endobiotic lingulates were also
symbionts of tabulate corals in the Katian of Estonia. Bryozoans hosted the most
diverse fauna of endobionts in the Katian of Baltica. Corals and stromatoporoids
hosted just few groups of endobionts in the Katian of Baltica.
... The Ordovician bryozoans of Estonia are well-known (e.g., Bassler 1911;Modzalevskaya 1953;Männil 1959;Lavrentjeva 1990;Gorjunova 1992Gorjunova , 1996Pushkin and Gataulina 1992;Gorjunova and Lavrentjeva 1993). The eastern Baltic fauna of cornulitids in the Ordovician is somewhat less studied (Vinn and Mõtus 2012;Vinn 2013, Vinn andMadison 2017), but only a single case of intergrowth between cornulitids and other invertebrates has been previously reported from the Ordovician of Estonia (Vinn and Mõtus 2012), and this topic definitely needs further study. ...
... The Ordovician bryozoans of Estonia are well-known (e.g., Bassler 1911;Modzalevskaya 1953;Männil 1959;Lavrentjeva 1990;Gorjunova 1992Gorjunova , 1996Pushkin and Gataulina 1992;Gorjunova and Lavrentjeva 1993). The eastern Baltic fauna of cornulitids in the Ordovician is somewhat less studied (Vinn and Mõtus 2012;Vinn 2013, Vinn andMadison 2017), but only a single case of intergrowth between cornulitids and other invertebrates has been previously reported from the Ordovician of Estonia (Vinn and Mõtus 2012), and this topic definitely needs further study. ...
... The thin and low rim around the cornulitid aperture does not provide any evidence of the bryozoan's attempt to overgrow an infesting organism. The architecture of this association is very similar to many other Paleozoic symbiotic associations of worm-like organisms and large colonial animals (Zapalski 2009;Zapalski and Hubert 2011;Vinn and Mõtus 2012). In these associations worm-like symbionts are always oriented perpendicular to the growth surface of large colonies; their bodies are always completely embedded within the host colony leaving only apertures free on the host's growing surface. ...
Three species of trepostome bryozoans formed syn vivo associations with the Cornulites in the Late Ordovician of Estonia. Cornulites sp. and Mesotrypa excentrica presumably formed a true symbiotic association. This is the first known case of symbiosis between cornulitids and bryozoans. It is not known whether this symbiotic association was obligatory of facultative for the cornulitid, but it was facultative for the bryozoan. In this association cornulitids may have competed for the food with bryozoans and the association may have been parasitic. The remaining associations between cornulitids and bryozoans were accidental. Most common skeletonized endobionts of the Ordovician bryozoans were not cornulitids, but conulariids and rugosans.
... The Ordovician of Baltica has a relatively good record of certain and possible cases of symbiosis (Männil, 1959;Vinn and Mõtus, 2012;Vinn et al., 2014a, b). In this study we focus only on confirmed cases of symbiosis where the skeletal structures indicate that both organisms were growing together. ...
... In this study we focus only on confirmed cases of symbiosis where the skeletal structures indicate that both organisms were growing together. Conulariids (Männil, 1959), cornulitids (Vinn and Mõtus, 2012) and possible polychaetes (Männil, 1959;Vinn, 2004Vinn, , 2005Vinn et al., 2014a,b) were common symbionts in bryozoans and tabulate corals of the Ordovician of Baltica. ...
... Among tabulates, associations with cornulitids and possible polychaetes (i.e. Chaetosalpinx) are known (Vinn and Mõtus, 2012). Only three symbiotic associations between non-colonial animals, hosted by brachiopods (i.e. ...
... Endosymbiotic growth within the host organisms has also likely been an antipredatory strategy (Vinn, 2009;Vinn and Mõtus, 2012). Symbiotic embedment within the skeleton of the host is a relatively old evolutionary feature in tentaculitoids (Late Ordovician; Vinn and Mõtus, 2012), but the earliest polychaete endobionts are known from the Cretaceous brachiopods (Kiel, 2008) and corals (Luci et al., 2021), which is relatively late as compared to tentaculitoid evolution. ...
... Endosymbiotic growth within the host organisms has also likely been an antipredatory strategy (Vinn, 2009;Vinn and Mõtus, 2012). Symbiotic embedment within the skeleton of the host is a relatively old evolutionary feature in tentaculitoids (Late Ordovician; Vinn and Mõtus, 2012), but the earliest polychaete endobionts are known from the Cretaceous brachiopods (Kiel, 2008) and corals (Luci et al., 2021), which is relatively late as compared to tentaculitoid evolution. However, the late appearance of endobiotic serpulids may actually represent the gap in our knowledge as their potential hosts in the early Mesozoic, such as stromatoporoids and corals, have not been systematically studied for endobionts. ...
In the present paper we trace the patterns of convergent evolution of encrusting calcareous polychaetes and tentaculitoids with respect to the morphology and function of their tubes. Both clades have morphologically similar tubes. Six of the eight basic morphotypes of encrusting tubeworms occur both in calcareous polychaetes and in tentaculitoids. All six encrusting tentaculitoid tubeworm morphotypes distinguished have analogues among serpulid and sabellid polychaetes. Both tentaculitoids and polychaetes with calcareous tubes have a similar plesiomorphic morphotype, which is characterized by substrate parallel, irregular growth away from the initial point of encrustation. Dominance of similarities in the order of evolution of morphotypes in the calcareous tubeworms indicates that despite genetic differences, ecological similarities (suspension feeding) and similarities in the tube material (calcareous), as well as body plan (worm-like) had a strong control over the evolution of calcareous tubeworms. The calcareous tubeworm life modes likely appeared in the order of increasing dependence on the type of substrate. In general, possible antipredatory strategies (spines, keels, cryptic and endobiotic mode of life) of calcareous tubeworms are evolutionarily old. The plesiomorphic general hard substrate encrusters are evolutionarily the most successful and have the longest stratigraphic range both in tube-dwelling polychaetes and tentaculitoids. Innovations, such as attachment of the tube by basal projections were developed in some microconchid tentaculitoids but not in calcareous polychaetes; budding tubes occur in both taxa, however, in 2 microconchid tentaculitoids it was a brief evolutionary event, whereas in polychaetes such pseudocolonies have a long stratigraphic range. The ability to live in brackish and fresh waters by some tentaculitoids and tube-dwelling polychaetes seems not to be associated with any particular tube morphotype.
... Conchicolites may have preferred to settle on non-living hard substrates. There are no previous reports of Conchicolitesbryozoan symbiosis, but endobiotic Conchicolites has been described from Late Ordovician tabulates of Estonia (Vinn and Mõtus, 2012). It is not known whether Conchicolites hosholmensis was an obligatory coral symbiont, or if it occurred as encrusters on biogenic and abiogenic substrates, as well. ...
... It is not known whether Conchicolites hosholmensis was an obligatory coral symbiont, or if it occurred as encrusters on biogenic and abiogenic substrates, as well. The relatively thin walls of C. hosholmensis could be interpreted as indicating obligatory symbiosis (Vinn and Mõtus, 2012). In contrast to the Conchicolites-tabulate association, the Conchicolites-Fistulipora association probably was accidental. ...
... Alternatively, endobiotic conulariids may have been dwarfed forms of free-living conulariids that died at mature ages. The architecture of these bryoimmurations is similar to many Paleozoic symbiotic associations between worm-like organisms and large colonial animals (Oekentorp, 1969;Zapalski, 2009;Zapalski and Hubert, 2011;Vinn and Mõtus, 2012). In the latter associations, elongate symbionts are always oriented perpendicular to the growth surface of large colonies; their bodies are always completely embedded within the host colony, leaving only their apertures free on the host's growing surface. ...
... The number of symbiotic associations involving bryozoans increased markedly in the Late Ordovician and this could be related to the GOBE (Vinn et al., 2018). Vinn and Mõtus (2012) suggested that increased diversity of animals with massive skeletons such as corals, stromatoporoids and bryozoans, combined with the increased predation pressure, created perfect conditions during the GOBE for the rapid evolution of endobiotic symbionts among biomineralizing and nonbiomineralizing taxa. ...
The trepostome bryozoans Diplotrypa abnormis, D. bicornis, D. petropolitana, Esthoniopora communis, Esthoniopora subsphaerica, Mesotrypa excentrica, M. expressa, M. raritabulata, and Monotrypa jewensis have symbiotic associations with the conulariid Climacoconus bottnicus in the Upper Ordovician of Estonia. All bryoimmured conulariids are very small and oriented perpendicular (or nearly so) to the growth surface of the host trepostome colony. Muddy seafloors may have promoted this symbiosis between conulariids and bryozoans because the former required a hard substrate for attachment. It is possible that the numerous smaller specimens among endobiotic conulariids usually died as juveniles together with their bryozoan host, or alternatively, the smaller endobiotic conulariids may have been Lilliput forms of free-living conulariids that died at a mature age. Conulariid-trepostome associations were likely not a result of accidental intergrowth of two organisms. Additional protection against predators provided by the calcitic bryozoan skeleton may have been among the benefits for the conulariid symbionts. Usually trepostomes with conulariid symbionts do not contain other invertebrates, but in the Katian in some cases they also hosted Anoigmaichnus bioclaustrations. The exact type of symbiosis between trepostomes and conulariids remains unresolved, but most likely the associations were slightly parasitic or commensal. The available data suggest that bryozoans preferred cnidarians over the other invertebrates as symbionts.
... A bioclaustration is created when a skeletonized host organism embeds a symbiont within its mineral tissues (Palmer and Wilson, 1988). These symbiont cavities in host organisms have only rarely been reported from the Ordovician (Palmer and Wilson, 1988;Tapanila, 2005;Vinn and Mõtus, 2012). The Ordovician was a time of significant biodiversification, termed the Great Ordovician Biodiversification Event (GOBE). ...
... Worm bioclaustrations have previously been described from the Late Ordovician corals of Baltica (Vinn and Mõtus, 2012). The earliest parasites in Baltica are known from the Middle Ordovician bryozoans of northern Estonia (Vinn personal observations). ...
... This diversification was a part of the large Ordovician radiation, and as a result numerous and ecologically diversified groups of invertebrates colonized the early Palaeozoic seafloors (Servais et al., 2010). Increasing complexity of modes of life, including feeding, motility and position in the sediment or water column, among others, triggered interspecific relationships between various organisms (e.g., Vinn and Mõtus, 2012;Vinn and Wilson, 2015). Most modern crinoids, unlike their Palaeozoic relatives, are unstalked forms; in today's seas stalked crinoids are comparatively rare, restricted to deeper environments, and similar to their Palaeozoic relatives, are passive suspension feeders (Macurda and Meyer, 1974). ...
Coral-crinoid associations, where a coral overgrew a crinoid's stem, were among the very common Palaeozoic benthic associations, lasting until the end of the Palaeozoic. Many skeletal overgrowths described so far document syn vivo relationships. This type of interaction is unknown from later, Meso-and Cenozoic deposits, and to date has been unknown from recent seas. Here we analysed two individuals of the crinoid Metacrinus rotundus collected from mesophotic depths off the Japanese Pacific coast, overgrown by a single zoantharian polyp of Abyssoanthus sp. (Anthozoa: Hexacorallia: Zoantharia: Abyssoanthidae), and by some sea anemones identified as Metridioidea sp. indet. (Hexacorallia: Actiniaria). These azooxanthellate hexacorals do not possess skeletons, and were located below the host's feeding fan. Our microtomography examinations showed that the anemones did not modify the host's columnals. These specimens offer a good ecological analogue to similar associations of rugose, Cladochonus-like and tabulate corals known from the Palaeozoic. While in our specimens competition for food between hexacorals and crinoid likely does not occur, such interactions are possible. Both zoantharians and sea anemones show similar corallite/oral disc diameters to rugose corals and Cladochonus-like cnidarians that overgrew crinoids in the Palaeozoic, and therefore they probably obtained similar sizes of food particles. In environments with low relief seafloors these hexacorals benefited from their elevated position, and therefore stronger feeding currents. As both Actiniaria and Zoantharia have their phylogenetic roots deep in the Palae-ozoic, and coral-crinoid associations are common among Palaeozoic tabulate and rugose corals, we speculate that also Palaeozoic non-skeletal corals, inferred from molecular studies, may have also developed this strategy of settling on crinoids, and therefore occupying similar ecological niches to these hexacorals described here. This report documents that coral-crinoid associations, characteristic of Palaeozoic benthic communities, and thought to have disappeared by the end of Permian, exist in modern seas.
... Thus, Silurian cornulitids were prone to symbiosis with other invertebrates. There may have been a slight escalation in the evolution of the endobiotic life mode in cornulitids as the number of such associations increases from the Ordovician (Dixon 2010;Vinn & Mõtus 2012;Vinn et al. 2018a) to the Silurian (Franzén 1974;Dixon 2010;Vinn & Wilson 2016). The latter fact supports predator-driven evolution of endobiotic life modes among cornulitids (Vinn 2009(Vinn , 2010. ...
Cornulites sp. and Fistulipora przhidolensis formed a symbiotic association in the Pridoli (latest Silurian) of Saaremaa Island, Estonia. This Cornulites sp.–F. przhidolensis association is the youngest example of cornulitid–bryozoan symbiosis. Symbiosis is indicated by intergrowth of both organisms. The cornulitids are completely embedded within the cystoporate bryozoan colony, leaving only their apertures free on the growth surface of bryozoan. In terms of food competition, this association could have been slightly harmful to F. przhidolensis as Cornulites sp. may have been a kleptoparasite. There may have been a small escalation in the evolution of the endobiotic life mode of cornulitids as the number of such associations increased from the Ordovician to Silurian. It is likely that Palaeozoic bryozoan symbiosis reached its maximum in the Late Ordovician. Most of the symbiotic bryozoans in the Palaeozoic are trepostomes, and the diversity of symbiotic associations was also greatest among trepostomes.
... During the Great Ordovician Biodiversification Event (GOBE), as increasingly complex ecosystems were becoming more extensive and diverse, symbiotic relationships between organisms also evolved, including examples of both parasitism and commensalism (Servais and Harper, 2018). These relationships are often difficult to identify in the fossil record due to a lack of direct evidence, but examples of probable symbiotic relationships between drilling and encrusting symbionts and their hosts are known from the Ordovician in a number of marine invertebrate groups, including graptolites (Bates and Loydell, 2000), echinoderms (Deline, 2008), chitinozoans (Grahn, 1981), bryozoans (Palmer and Wilson, 1988), corals (Vinn and Mõtus, 2012), and brachiopods (Vinn, 2005;Zhan and Vinn, 2007;Vinn et al., 2014). ...
An example of parasitic drilling in a rhynchonelliform brachiopod is described from the Shiyanhe Formation (Katian, Upper Ordovician) of Henan, central China. The boring extends into the shell almost perpendicular to the surface. The shell has been serially sectioned, and the trace (including boring and bioclaustration) has been modeled in three dimensions. Healing of the shell evident in serial sections supports a long-term relationship between the brachiopod and borer that we interpret as parasitic. Platyceratid gastropods, found at the same locality as these brachiopods, are the most likely drilling organism. Previous reports of Paleozoic brachiopod parasitic traces can be classified into two main groups, constructive association and destructive association, depending on whether parasites damage brachiopod shells. The example in this study belongs to the second type as the brachiopod shell has been partly damaged by the borer.
http://dx.doi.org/10.1017/jpa.2019.102
... The earliest tabulate hosted symbiotic associations are known from the Late Ordovician (Tapanila 2005). Late Ordovician tabulates hosted cornulitids both in Baltica (Vinn and Mõtus 2012) and Laurentia (Dixon 2010). Chaetosalpinx and Helicosalpinx bioclaustrations are common in the Late Ordovician tabulates of North America (Tapanila 2004). ...
Rare symbiotic rugose corals in tabulates occur in the lower Rhuddanian strata of Estonia. Thirteen out of 1115 coralla of early Rhuddanian tabulate corals of Estonia and two out of 353 coralla of Sheinwoodian tabulate corals of Gotland and Estonia contain rugose coral endobionts. Endobiotic rugose corals occur in Paleofavosites balticus (Linnaeus 1767), Paleofavosites sp., Mcleodea sp., Heliolites interstinctus (Linnaeus 1767), and Catenipora gotlandica (Yabe 1915). Endobiotic rugose corals include Tryplasma sp., Helicelasma sp., Streptelasma estonica Dybowski 1873, Streptelasma sp., Kodonophyllum cf. tubaeformis Kaljo 1957, and Palaeophyllum? sp. The latter rugose corals commonly occur independently from tabulates in the early Silurian of Estonia. It is most likely that symbiosis between rugose corals and tabulates was not obligate, but facultative. Symbiotic rugose corals presumably benefitted from growth within a stable (positionally) substrate. Rugose corals seem to have no strong negative effect on the growth of tabulates.
... The discovery of the Anoigmaichnus odinsholmensis and Mesotrypa bystrowi assemblage indicates that the endobiotic symbiont diversity was higher in the Ordovician than previously thought. This new symbiotic endobiont and other similar recent discoveries from the Ordovician ( Dixon, 2010;Vinn and Mõtus, 2012a,b) show that the early diversification of endobiotic symbionts was more intense than previously known and presumably reflected the GOBE. The combination of several geological and biological processes helped generate the GOBE ( Servais et al., 2009). ...
... The record of hard substrate trace fossils is much more complete, comprising Trypanites borings in brachiopods (Vinn 2005) and bryozoans (Wyse Jackson & Key 2007). Recently bioclaustrations have also been described from the Ordovician of Estonia (Vinn & Mõtus 2012). ...
The ichnogenus Oikobesalon is here described from the Ordovician of Baltica for the first time. All the specimens in this study were found on Osmussaar Island, Estonia. They belong to the ichnospecies Oikobesalon coricaceum. In the Cambrian and Ordovician, Oikobesalon seems to have occurred only in cold to temperate seas. The Oikobesalon trace-maker presumably used its burrow permanently for dwelling and searched for its food through the burrow aperture that likely opened to the sediment-water interface.
... The earliest macroscopic endobiotic invertebrate symbionts are known from the Late Ordovician of North America and Baltica (Elias, 1986;Tapanila, 2005;Dixon, 2010;Vinn and Mõtus, 2012). These endobionts are among the best examples of symbiotic interactions in the fossil record (Taylor, 1990;Taylor and Wilson, 2002). ...
A new bioclaustration of a symbiont is here described from the mantle cavity of the strophomenatan brachiopod Clitambonites schmidti. It is the second bioclaustration in brachiopods known from the Kukruse Regional Stage (Sandbian) of Estonia. It shares affinities with the bioclaustrations Burrinjuckia and Haplorygma. The outgrowth in the ventral valve interior was secreted by the brachiopod around a symbiont. Most likely the symbiont was a suspension feeder that collected food particles from the brachiopod's mantle cavity. The symbiont was either a kleptoparasite or fed on the brachiopod's feces (coprophagy). The majority of symbiosis cases in brachiopods in the Ordovician of Baltica involve clitambonitids as the hosts. Thus, clitambonitid brachiopods were more likely hosts for symbiosis than other brachiopods in the Ordovician of Baltica.
Tentaculitoid tubeworms, an extinct invertebrate group, is being reported from the Ordovician strata of Spiti, Tethyan Himalaya, India. External and internal moulds of tentaculitoids are preserved in the lower unit of the Takche Formation which is considered early Late Ordovician in age. The assemblage includes Cornulites cf. sterlingensis, Cornulites zatoni, Cornulites sp., and Tentaculites spp. Cornulites cf. sterlingensis, Cornulites sp., and Cornulites zatoni are recorded and described for the first time from the Ordovician strata of India. Though, the occurrence of genus Tentaculites is previously mentioned from the Early Palaeozoic sequence of Spiti, the detailed documentation is provided herein for the first time from the Ordovician sequence of Spiti, India. The occurrence of solitary-free forms of tentaculitoids from shallow marine settings of Spiti, Tethyan Himalaya, India indicates that unattached free forms might have been more competent in the siliciclastic environment of relatively low palaeolatitude than carbonate platforms of lower palaeolatitudes and silici-clastic environments of the highest palaeolatitudes. ARTICLE HISTORY
An endosymbiotic relation between the solitary rugose corals ?Yuanophyllum and ?Dibunophyllum and a large soft-bodied worm-like organism is described from the Hezhou Formation (Serpukhovian), Lower Yangtze Platform, South China. The endosymbiont lived in a U-shaped tube, probably with a horizontally sideways bent base connecting the vertical shafts. A membranous epidermis and relicts of a probable cuticulo-muscular tube are preserved. The corals reacted with skeletal encasement of the infesting organism and irregular, in part dense growth of additional skeletal elements adjacent to it. This is the first description of such an endosymbiotic, parasitic or commensal relation of solitary rugose corals after the Frasnian-Famennian Boundary Event. Similarities between the Devonian association of pleurodictyoform tabulates and the ichnotaxon Hicetes are remarkable. Moreover, the association proves the extraordinarily rare persistence of bioclaustrations in corals after the Hangenberg Event at the Devonian-Carboniferous boundary during the Permo-Carboniferous period of arrested endosymbiont development.
Endobiotic tentaculitoids formed symbiotic associations with tabulates, heliolitids, rugosans, bryozoans, crinoids, stromatoporoids, and chaetetids from the Late Ordovician to the Carboniferous. The Ordovician was dominated by coral hosts, but there was a shift from mostly coral-based associations to stromatoporoid-based associations in the early Silurian. Specialization increased during the evolution of tentaculitoid symbiosis. In the Devonian, specialized symbiotic endobiont genera appeared which did not occur separately from their hosts.
Newsletter of the International Association for Study of the Fossil Cnidaria and Porifera (IASFCP) - contains reports on current research and bibliographic notes of publications on fossil corals, sponges, and reefs.
Thirteen symbiotic associations occur in the Silurian of Baltica. Symbiosis was especially prominent among colonial animals, most commonly with stromatoporoids. These sponges hosted the most diverse fauna of endobiotic symbionts (including rugosans, Syringopora, ‘polychaetes’, cornulitids and lingulids). This pattern can be explained by the abundance of stromatoporoids in the Silurian of Baltica and their large skeletal volume, making them attractive hosts for smaller invertebrates. There is an evolutionary trend of an increasing number of different pairs of symbiotic taxa from the Llandovery to the Ludlow, with a remarkable increase in the Ludlow. This is likely related to an increase in the number of mutualistic taxa that could have had evolutionary advantages over organisms less amenable to symbiosis. The number of different pairs of symbiotic taxa also increased in the Wenlock, which may be linked to delayed recovery from the end-Ordovician mass extinction.
Multiple bioclaustrations identified as possible Chaetosalpinx are reported from a stromatoporoid of Rhuddanian age from Hiiumaa Island, Estonia. This is the second record of symbiotic worm endobionts from the end-Ordovician mass extinction recovery fauna of Estonia. The end-Ordovician mass extinction did not terminate complex ecological relationships between at least some worm endobionts and their hosts.
Numerous tiny curved to slightly sinuous subvertical tubicolous bioclaustrations occur in stromatoporoids from the Katri cliff biostrome. About 77.8% (N=18) of Katri biostrome stromatoporoids contained worm endobionts. Chaetosalpinx sibiriensis occurs in Plectostroma scaniense, Petridiostroma convictum and "Stromatopora" bekkeri/Parallelostroma typicum. Helicosalpinx concoenatus occurs in P. scaniense. The distribution of C. sibiriensis is thus not restricted to tabulate corals because it also occurs in stromatoporoids. H. concoenatus was not endemic to North America as it also occurs in the Late Silurian of Baltica.
Abstract: Protoheliolites is an early heliolitine coral characterized
by closely spaced corallites separated in places by
sparse coenenchyme. Growth characteristics in the type species,
P. norvegicus, are revealed by detailed analysis based on
serial peels and thin sections of coralla from the uppermost
Katian of north-western Estonia. Colonies of this species had
a strong ability to recover from damage and partial mortality,
resulting in various forms of rejuvenation, regeneration,
fusion and reorganization of corallites; in some cases, this
involved relatively large areas of undifferentiated soft parts.
The shells of commensal cornulitids became enclosed in host
coralla during colony growth. Coralla of P. norvegicus exhibit
distinctive growth cycles due to responses to seasonal
changes. The production of new corallites by coenenchymal
increase usually occurred in low-density bands, in which
corallites generally display round to subrounded transverse
outlines. In high-density bands, the corallites became crenulated,
their wall thickness increased, septal development was
more pronounced, and the amount of coenenchyme
increased. In addition to these cyclomorphic changes, there
were significant astogenetic changes during growth. Compared
with the early stage of colony development, distinctive
characteristics in the late astogenetic stage include a decrease
in the growth rate of the colony, better coordination among
corallites, maximum development of corallite crenulations
and septa in high-density bands, more numerous coenenchymal
tubules and a greater proportion of corallum area occupied
by coenenchyme. In general, the role of polyps in
determining morphological characteristics of individual corallites,
such as tabularium area, corallite crenulations and
wall thickness, was subordinate to the astogeny of the colony.
Growth characteristics including colony-wide coordination
of polyp behaviour and subjugation of individuals to
restore the colony following damage suggest a strong astogenetic
control and high level of colony integration. Protoheliolites
probably arose from a heliolitine genus rather than from
a nonheliolitine group as some authors have proposed.
Nine species of cornulitids are systematically described here from the Ordovician of Estonia. The earliest species, Cornulites semiapertus, appears in the late Darriwilian (Middle Ordovician), the next two species appear in the Sandbian and there are a further six new species in the Katian, which indicates a rapid diversification of cornulitids in the Late Ordovician of Baltica. All the studied cornulitids from the Ordovician of Estonia occur in relatively shallow-water normal-marine sediments of a carbonate platform. The cornulitids are found encrusting mostly brachiopod shells (both syn vivo and post mortem).
Tabulate corals are sometimes associated with other organisms occurring within their skeletons. These tabulate endobionts are common in Lower Palaeozoic (Ordovician and Silurian) and Devonian strata, but until now they have not been recognized in strata younger than early Frasnian. Here we report ?Chaetosalpinx sp. occurring within the skeletons of the tabulate coral Yavorskia sp. (Favositida, Cleistoporidae) from the latest Famennian ("Strunian") in the Etroeungt area (Northern France). It can be stated that these endobionts survived the Frasnian-Famennian boundary crisis and recovered in the Late Famennian.
Symbiotic associations are a poorly studied aspect of the fossil record, owing largely to the taphonomic
biases that inhibit direct observation that two organisms shared an intimate association in life. A symbiosis
between an infesting animal and a skeleton-producing host can form a bioclaustration cavity that directly
preserves the association and has a high preservation potential. Identifi cation of ancient mutuals and parasites must reject the null hypothesis of commensalism by demonstrating that the symbiosis correlates with a positive or negative change in host fi tness as compared to a non-symbiotic relative of the host taxon. Reviews of the Paleozoic record of marine symbionts show that the majority are hosted by colonial animals, especially corals and calcareous sponges. These hosts include structural forms that have moderate to high levels of integration and can support bioclaustrations between clonal units, mitigating the negative effects of symbionts, and perhaps facilitating the symbiosis.
The fossil record is biased toward recording long-lasting, widespread, equilibrated associations. By contrast, parasitisms that are especially negative to the host are expected to be fossilized rarely. The symbiotic associations that form bioclaustrations may also represent an endolithic adaptive strategy in response to biological antagonisms, such as predation and spatial competition. The Late Ordovician rise in symbiotic bioclaustrations joins burrows and borings as trace fossil examples of infaunalization strategies that accompany the Ordovician faunal radiation.
Two species of endobiotic cornulitids are described from heliolitid corals of the Katian (Late Ordovician) of Estonia. They are thus far the earliest known showing this symbiotic relationship. Conchicolites hosholmenis n. sp. represents the only known symbiotic coral endobiont species in the genus. Cornulites sp. aff. Cornulitescelatus closely resembles the North American endobiotic species C. celatus from tabulates of the Hirnantian (Late Ordovician).
Organisms of unknown biological affinities, assigned to the genus Chaetosalpinx, are known to infest Palaeozoic tabulate corals and stromatoporoids. Analysis of distribution of these parasites, performed on Emsian-Eifelian material of Favosites goldfussi (Anthozoa, Tabulata) from the Northern Region of the Holy Cross Mountains (Poland), shows that parasites were absent in the early astogenetical stages, and that during astogeny both the absolute number of parasites per colony and the number of parasites per polyp were increasing. The latter can reach 2.7 parasites per polyp. Preferred settling places are in corallite corners (junction of three individuals), but dense infestation also produced settlement in the corallite walls (between two individuals). Probable causes of the increase are insufficient protection by host's cnidae, insufficient immune system response, and parasite ability to adapt to the host's defences.
Calcareous tube-worms generally identified as Spirorbis range from
Ordovician to Recent, often profusely encrusting shells and other
substrates. Whereas Recent Spirorbis is a polychaete annelid, details of
tube structure in pre-Cretaceous `Spirorbis' suggest affinities with the
Microconchida, an extinct order of possible lophophorates. Although
characteristically Palaeozoic, microconchid tube-worms survived the
Permian mass extinction before being replaced in late Mesozoic
ecosystems by true Spirorbis. Recent Spirorbis is stenohaline but
spirorbiform microconchids also colonized freshwater, brackish and
hypersaline environments during the Devonian-Triassic. Anomalies in the
palaeoenvironmental distributions of fossil `Spirorbis' are explained
with the recognition of this striking convergence between microconchids
and true Spirorbis.
Cylindrical tubes or the trace fossil Chaetosalpinx occur within the skeletal walls of Late Ordovician sarcinulid tabulate corals preserved on Anticosti Island. A large host-specific embedment structure, Chaetosalpinx rex isp. nov., is described from the reefal sarcinulid genus Columnopora that occurs in (Rawtheyan, Ashgill) coral-stromatoporoid patch reefs of the upper Vauréal Formation (Mill Bay Member). While locally abundant in Columnopora, this newly described embedment structure is absent in other frame-builders in the reefs.
Tube-like traces of organisms belonging to the ichnogenus Chaetosalpinx Sokolov have been considered in the literature as commensal endobiontic organisms of tabulate corals. Their position between the corallites (or sometimes within the septa), perforation of the host's skeleton and soft tissue, modification of its phenotype and a possible inhibition of its growth show that the relationship between these organisms and tabulate corals can best be interpreted as parasitism rather than commensalism, as previously suggested. Such an interpretation may be extended to the ichnogenera Helicosalpinx Oekentorp and Actinosalpinx Sokolov, which show identical placement within the host colony and similar features, such as the absence of their own wall.
The earliest known record of lingulid-coral associations is described from Ashgill tabulate corals preserved on Manitoulin Island, Ontario. Lingulid infestation of tabulate corals and stromatoporoids also is locally abundant in Ashgill and Llandovery limestones on Anticosti Island, Québec, and these preserve the new lingulid species Rowellella? anticostiensis inside the cavities of Trypanites borings. In all examples, lingulids appear to nestle in previously formed Trypanites, likely in a dead host coral or stromatoporoid. In some instances in the Silurian of Anticosti, regeneration of host growth while infested by lingulids is evidenced by a new type of compound trace fossil, Klemmatoica linguliforma new ichnogenus and ichnospecies. Similar endosymbiotic relationships previously observed in Silurian corals from Wales and Sweden suggest that the lingulid association with tabulate corals and stromatoporoids was widespread in early Paleozoic shallow marine settings.
Spiral embedment cavities that formed around metazoan endosymbionts are preserved in the septa and intercorallite spaces of Columnopora and Calapoeciacorals from Manitoulin Island, Ontario. These are the oldest described Helicosalpinx asturiana, and this report extends the range of these trace fossils from the Richmondian (Ashgill, Upper Ordovician) to the Givetian (upper Middle Devonian). The sinistrally coiled traces show regular morphology, suggesting a physiological basis for their shape. Coral growth parameters are not affected by the presence of Helicosalpinx, suggesting that the endosymbiont was not parasitic and not in direct competition for resources with the host. H. asturiana is interpreted as trace fossil evidence of commensalism.Two additional endosymbiotic traces occur in Late Ordovician Columnopora. The particular association of straight, cylindrical Chaetosalpinx with Columnopora is widespread during the Richmondian. A dependent association is suggested to have originated between the endosymbiont and Columnopora prior to the Richmondian expansion and to have continued into the Hirnantian (latest Ordovician). The association between this endosymbiont and host is the earliest known temporally and globally significant inter-metazoan symbiosis. Although host corals, Columnopora and Calapoecia, did not survive the end-Ordovician mass extinction events, both Chaetosalpinx and Helicosalpinx occur in other host corals during the Silurian and Devonian.
The following differences were found between the members of the cornulitids, Cornulites and Conchicolites. Both genera have egg-shaped embryonic shells, which presumably calcified after the settling of larva to the substrate, but the embryonic shells in Cornulites are larger than in Conchicolites. Cornulites has a regularly foliated shell ultrastructure and pseudopuncta, whereas the shell ultrastructure in Conchicolites is prismatic. In Cornulites the outer part of the shell contains numerous vesicular cavities that were never observed to cross the interspaces of the surface annulae, indicating cyclic shell secretion. In several species the vesicles are internally coated by calcitic lamellae that are oriented subparallel to the shell surface. In Conchicolites the vesicular shell structure is absent and the calcitic prisms are deposited at the shell aperture more or less at right angles to the longitudinal shell axis. The function of the surface annulae in Cornulites and transverse ridges in Conchicolites may have been to strengthen the shell wall and protect it against longitudinally developing cracks. Vesicular structure in Cornulites seems to have provided a stronger shell for less material and smaller cost of energy. Differences between Cornulites and Conchicolites indicate that the two taxa were probably unrelated and that cornulitids may be a polyphyletic taxon. Cornulites shares the most characters with the lophoporates and tentaculitids. Biological affinities of Conchicolites are controversial, and its morphologic features need further revision to affiliate this group with certainty to any extant animal phylum.
The problematic fossil Anticalyptraea Quenstedt, 1867, traditionally interpreted as a phorid gastropod, is here assigned to the Class Tentaculita. Its dextrally coiled substrate-cemented tube, bulbous initial chamber, vesicular tube wall and pseudopunctate microlamellar shell structure closely resembles Trypanopora (Tentaculita), but Anticalyptraea differs in having the cones of the pseudopunctae orientated in the opposite direction. Pseudopunctae orientated similarly to Anticalyptraea occur in Cornulites and thick-walled tentaculitids. Anticalyptraea differs from gastropods in having pseudopunctae and a vesicular shell structure.
The earliest endosymbiotic tubeworms have been discovered within skeletons of the tabulate coral Heliolites sp. from the Silurian (Ludlow) of Podolia, Ukraine. The new tubeworm species has a maximum diameter about I mm, a slightly conical tube, a smooth lumen in the tube and a lamellar wall structure. The tube wall is 0.05-0.10 mm thick. The new endosymbiotic tubeworm Coralloconchus bragensis n. gen. and sp. shares zoological affinities with the tentaculitids (incertae sedis) and is assigned to the Family Cornulitidae (Tentaculita, Comulitida).
Improved knowledge of the fossil record combined with molecular trees describing the phylogenetic relationships between recent phyla, is gradually advancing our understanding of the evolution of biomineralized marine invertebrates However relationships between the three extant lophophorate phyla Brachiopoda, Bryozoa and Phoronida have yet to be resolved, and the monophyletic status of Lophophorata has been called into question Here we review the phylogeny and biomineralization of lophophorates, along with some extinct groups that have been suggested to be lophophorates on the basis of skeletal structure and ultrastructure We conclude that blomineralized skeletons are not homologous in lophophorates the skeletons of brachiopods being plesiomorphic whereas biomineralization in bryozoans is apomorphic and has evolved independently twice from soft-bodied ctenostome grade bryozoan ancestors Phoronida nests within Brachiopoda, according to the molecular tree, and between two clades (rhynchonelliformeans and cranuformians) having calcareous shells, in which case stern group phoronids would likely have possessed calcareous skeletons too Both the solitary vermiform Tentaculitoidea (Ordovician Jurassic) and the colonial, bryozoan like Hederelloidea (Silurian-Permian) are here considered to be biomineralized stem group phoronids.
The new endosymbiotic cornulitid Cornulites stromatoporoides n. sp. is described here from the Sheinwoodian stromatoporoids of Saaremaa, Estonia. This new species represents the earliest record of cornulitid endosymbiosis, probably reflecting increased pressure by boring and durophagous predators on worms with mineral tubes in the Silurian. In lower Sheinwoodian open shelf marls, 30% of stromatoporoids are infested by C. stromatoporoides n. sp.; 77 % of stromatoporoids in upper Sheinwoodian shoal limestones also had this endosymbiotic relationship. C. stromatoporoides n. sp. has thus far only been found as an endosymbiont in stromatoporoids. There is a range of one to six, averaging 2.4, endosymbiotic C. stromatoporoides n. sp. specimens (syn vivo) per infested stromatoporoid in the lower Sheinwoodian. Large stromatoporoids contain more Cornulites endosymbionts than smaller stromatoporoids.
Morphological similarities indicate that Palaeozoic problematic tubeworms, e.g. tentaculitids, cornulitids, microconchids, trypanoporids, Anticalyptraea, and Tymbochoos, form a monophyletic group. This group may also include hederelloids. Members of this group share affinities with lophophorates and their evolution could have partly been driven by predation. The extinction of Palaeozoic tubeworms in the Middle Jurassic was possibly at least partly caused by the ecological pressure by serpulid and sabellid polychaetes. The input of Palaeozoic tubeworms to the general ocean biocalcification system may have been smaller in the Ordovician to Jurassic than that of calcareous polychaetes in the Late Triassic to Recent. There seems to have been some correlation between the aragonite–calcite seas and the skeletal mineralogy of Triassic–Recent polychaete tubeworms.
Although there have been numerous isolated studies and reports of symbiotic relationships of polychaetes and other marine animals, the only previous attempt to provide an overview of these phenomena among the polychaetes comes from the 1950s, with no more than 70 species of symbionts being very briefly treated. Based on the available literature and on our own field observations, we compiled a list of the mentions of symbiotic polychaetes known to date. Thus, the present review includes 292 species of commensal polychaetes from 28 families involved in 713 relationships and 81 species of parasitic polychaetes from 13 families involved in 253 relationships. When possible, the main characteristic features of symbiotic polychaetes and their relationships are discussed. Among them, we include systematic accounts, distribution within host groups, host specificity, intra-host distribution, location on the host, infestation prevalence and intensity, and morphological, behavioural and/or physiological and reproductive adaptations. When appropriate, the possible directions for further research are also indicated.
Endosymbionts are organisms that live within the growing skeleton of a live host organism, producing a cavity called a bioclaustration. The endosymbiont lives inside the bioclaustration, which it forms by locally inhibiting the normal skeletal growth of the host, a behaviour given the new ethological category, impedichnia . As trace fossils, bioclaustrations are direct evidence of past symbioses and are first recognized from the Late Ordovician (Caradoc). Bioclaustrations have a wide geographic distribution and occur in various skeletal marine invertebrates, including tabulate and rugose corals, calcareous sponges, bryozoans, brachiopods, and crinoids. Ten bioclaustration ichnogenera are recognized and occur preferentially in particular host taxa, suggesting host-specificity among Palaeozoic endosymbionts. The diversity of bioclaustrations increased during the Silurian and reached a climax by the late Middle Devonian (Givetian). A collapse in bioclaustration diversity and abundance during the Late Devonian is most significant among endosymbionts of host coral and calcareous sponge taxa that were in decline leading up to the Frasnian–Famennian mass extinction.
Two endosymbionts, Chaetosalpinx sibiriensis and Coralloconchus bragensis, occur in Silurian tabulate corals of Podolia. The endosymbiotic worms responsible for C. sibiriensis bioclaustrations in tabulates are found only in certain species: Paleofavosites cf. collatatus, Heliolites sp. A, Heliolites sp. B, Heliolites sp. C, Favosites gothlandicus, Favosites sp. A. One to six C. sibiriensis-infested tabulate species are known from Late Homerian to Ludfordian, in the reef-related community. Chaetosalpinx sibiriensis preferred certain tabulate species over the others, but showed no preference for the favositid or heliolitid type of morphology.
Symbiotic associations are a poorly studied aspect of the fossil record, owing largely to the taphonomic biases that inhibit direct observation that two organisms shared an intimate association in life. A symbiosis between an infesting animal and a skeleton-producing host can form a bioclaustration cavity that directly preserves the association and has a high preservation potential. Identification of ancient mutuals and parasites must reject the null hypothesis of commensalism by demonstrating that the symbiosis correlates with a positive or negative change in host fitness as compared to a non-symbiotic relative of the host taxon. Reviews of the Paleozoic record of marine symbionts show that the majority are hosted by colonial animals, especially corals and calcareous sponges. These hosts include structural forms that have moderate to high levels of integration and can support bioclaustrations between clonal units, mitigating the negative effects of symbionts, and perhaps facilitating the symbiosis.
The fossil record is biased toward recording long-lasting, widespread, equilibrated associations. By contrast, parasitisms that are especially negative to the host are expected to be fossilized rarely. The symbiotic associations that form bioclaustrations may also represent an endolithic adaptive strategy in response to biological antagonisms, such as predation and spatial competition. The Late Ordovician rise in symbiotic bioclaustrations joins burrows and borings as trace fossil examples of infaunalization strategies that accompany the Ordovician faunal radiation.
Four stromatoporoid species from a stromatoporoid biostrome in the middle Ludlow Hemse Beds, Gotland, Sweden, show intergrowths with syringoporid tabulate and rugose corals, and indicate close relationships between particular coral and stromatoporoid species. The stromatoporoid Clathrodictyon convictum always contains ?Syringopora and this tabulate is rarely found in the other stromatoporoids. C. convictum is also closely associated with Tryplasma flexuosum (rugosa) while Petrozium pelagicum (rugosa) occurs only in the stromatoporoids Plectostroma intermedium and Parallelostroma typicum. The microstructure of ?Syringopora within the stromatoporoids is composed of an inner lamellar layer and an outer radial layer of calcite crystals. Diagenetic alteration has affected the microstructure which differs from recently described Devonian forms having only a radial layer. This shows variability in the structure of the tabulates within stromatoporoids. Information is sparse on the range of such variation and assessment of the relative importance of taxonomic, palaeoenvironmental and diagenetic effects is not possible in the present sample. No evidence is found to prove the precise nature of the relationships; they were not parasitic but may have been mutually symbiotic, or (most probably) commensal. The results suggest that the corals selected the most suitable stromatoporoid species for their requirements. Stromatoporoid morphology may have had an important influence on the association, where corals are more abundantly associated with those stromatoporoid species which adopted a high profile. Overall the associations appear to have allowed the corals to explore higher energy habitats otherwise unavailable to their delicate branching structure.
The Upper Ordovician Pirgu Regional Stage of the East Baltic is represented by numerous formations, which characterize the lithological variability of the rocks and are used in the geological mapping of the region. Onshore-Offshore drill core profiles from northern Estonia to southern Lithuania provide data on the distribution and succession of the formations. The formations described are arranged into four groups, each comprised of units with similar and characteristic lithological composition and depositional facies. Chitinozoan biozonation and bentonite (K-bentonite) beds are used to correlate selected sections and in the facies analysis of the described formations. Special attention is paid to the age and interpretation of the Jonstorp Formation in the East Baltic and Scandinavia. Correlations of the Pirgu Stage across the East Baltic are presented, and the use of the last occurrence of the chitinozoan Acanthochitina barbata Eisenack as a marker for the lower boundary of the stage is discussed.
Symbiotic relationships involving physical contact between worms and solitary rugosan polyps are recorded by the following structures in North American Late Ordovician corals: (1) Trypanites borings enclosed within septal swellings in two specimens, (2) vermiform grooves and openings along the external wall of one corallum, and (3) a chamber containing a unique brown tube within one individual. These features are indicative, respectively, of commensal boring polychaete annelids that penetrated through coralla, commensal epizoic worms of unknown taxonomic affinity that attached to the side of a polyp, and a tubicolous worm (possibly a polychaete) that was likely a parasitic endozoan. Symbionts comparable to the latter two types are also known from two specimens of Devonian solitary rugose corals.
Indirect evidence suggests that symbioses between solitary rugosans and the worms that produced Trypanites borings as dwelling structures in the sides of coralla were relatively common. However, direct evidence that the hosts were alive has been found in only two corals. In both cases, worms bored through septa within the calices and came into contact with basal surfaces of the polyps, which secreted skeletal material that sealed off the intruders. The rarity of such structures suggests that the encounters were inadvertent. If boring worms favored upcurrent portions of objects in order to maximize feeding benefits and avoid sedimentation, their locations indicate that the concave sides of curved coralla faced toward prevailing currents when in life positions.
“Opportunistic” worms are known to have attached to the sides of polyps only in rare instances when the hosts became temporarily exposed as a result of accidents or abnormalities. This indicates that coralla normally served to shield polyps from colonization by nonboring epizoans.
Worms that apparently extended up through openings in basal surfaces of polyps likely obtained sustenance parasitically within the central cavities. They could have entered the hosts through their mouths, or via the calices when parts of the polyps detached from their coralla and contracted radially. The rarity of this type of relationship in solitary Rugosa suggests that the worms entered inadvertently.
Symbioses involving physical contact between worms and polyps seem to have been rare throughout the history of solitary rugose corals. Both groups apparently tolerated such associations when they did occur, although the rugosans secreted structures in their coralla that served to isolate the symbionts. In doing so, they recorded the presence of worms not likely to be preserved as body fossils. The interpretation of such features provides information on the physiology and ethology of both organisms, on the history of symbiotic relationships, and on the diversity of soft-bodied organisms in ancient environments.
The new ichnogenus Tremichnus is proposed to include simple circular-parabolic pits, with or without associated stereom swellings, on fossil echinoderms, primarily crinoids. Tremichnus is a common trace fossil that is largely confined to columns and calyces of Paleozoic crinoids; the ichnogenus ranges at least from Middle Ordovician to Permian, and perhaps into the Mesozoic. Four new ichnospecies are also defined: T. paraboloides, the type species, comprising deep circular-parabolic pits, 0.15-3.5 mm, without associated gall-like swellings: T. cysticus, similar, though smaller pits surrounded by cystose masses of stereomatic secretion; T. minutus, uniformly small, non-overlapping pits commonly surrounded by raised rims; and T. puteolus, very large, shallow pits generally with a concentric inner ring-like groove. A similarly large pit, T. sp. aff. T. puteolus occurs on diploporitan cystoids. Review of mode of occurrence of these pits suggests that Tremichnus was the work of a sessile, host-selective epibiont, probably a parasite or a commensalistic filter feeder. The pits were apparently produced by a combination of embedment (i.e., inhibition of stereom growth) and some true boring (i.e., removal of stereom). -Author
Brett, Carlton E. 197807 15: Host-specific pit-forming epizoans on Silurian crinoids. Lethaia, Vol. 11. pp. 217–232. Oslo. ISSN 0024–1164.
Circular-parabolic pits occur commonly on the endoskeletal remains of certain Paleozoic crinoids. Detailed study of several hundred specimens, representing about 30 pelmatozoan species from the Upper Silurian Rochester Shale of New York and Ontario, reveals that such pits occur exclusively in seven species of crinoids. Furthermore, there are consistent differences in the morphology and orientation of holes occurring on the different crinoid species. This suggests that distinct epizoan species settled selectively on given hosts. The relationship between the hole-producing epizoans and crinoid hosts is inferred to have been a form of dependent commensalism. Preliminary surveys of other Paleozoic crinoid assemblages reveal similar host-selectivity by pit-producing epizoans. Crinoidepizoan pairs apparently co-evolved through considerable spans of geologic time as related genera and species of different ages, from Silurian to Pennsylvanian, exhibit similar pits.
Conoidal shells of Cornulites celatus n. sp. occur commonly within host coralla of Propora conferta Milne-Edwards and Haime, 1851, sensu lato, from the Laframboise Member of the Ellis Bay Formation (Ashgill: Upper Ordovician) at Pointe Laframboise on western Anticosti Island. Examples have also been found at the same locality in the tabulate corals Paleofavosites sp., Acidolites arctatus Dixon, 1986, and A. compactus Dixon, 1986, and the stromatoporoid Ecclimadictyon sp., but not in other associated tabulate coral species. Growth interference between the shells and their hosts indicates a commensal relationship. C. celatus apparently had a more limited paleoenvironmental range than its principal coral host species, which occurs abundantly elsewhere on the island without its endobiotic partner. The diagnosis of Cornulites is emended to include forms having a two-layered shell wall with a distinctive outer layer consistently preserved as prismatic calcite. This new species extends the known stratigraphic range of cornulitids in commensal relationships with corals and stromatoporoids from the Silurian back to the Upper Ordovician.
The adult shell (teleoconch) of the enigmatic tubular Givetian fossil Trypanopora is comprised of two principal layers: an outer fibrous prismatic layer and an inner micro-lamellar (irregular cross-bladed) layer, with local, closely-spaced disruptive punctation. The fine preservation suggests an original calcite composition. The shell microstructure shows great similarities with that of both vermiform ‘gastropods’ and tentaculitoids, suggesting a close affinity between Trypanopora and these groups. The septa have an irregular micro-lamellar (cross-bladed) microstructure in continuity with the inner wall, and a morphology unlike that of any known mollusc. The class Tentaculitoidea is emended to include two new orders: Microconchida for the vermiform ‘gastropods’ and Trypanoporida for Trypanopora and allied genera. □Trypanopora, microstructure, protoconch, teleoconch, fibrous prismatic layer, micro-lamellar layer, tubulation, septation, vermiform ‘gastropods’, Tentaculitoidea, Microconchida, Trypanoporida.
Four stromatoporoid species from a stromatoporoid biostrome in the middle Ludlow Hemse Beds, Gotland, Sweden, show intergrowths with syringoporid tabulate and rugose corals, and indicate close relationships between particular coral and stromatoporoid species. The stromatoporoid Clathrodictyon convictum always contains ?Syringopora and this tabulate is rarely found in the other stromatoporoids. C. convictum is also closely associated with Tryplasma flexuosum (rugosa) while Petrozium pelagicum (rugosa) occurs only in the stromatoporoids Plectostroma intermedium and Parallelostroma typicum. The microstructure of ?Syringopora within the stromatoporoids is composed of an inner lamellar layer and an outer radial layer of calcite crystals. Diagenetic alteration has affected the microstructure which differs from recently described Devonian forms having only a radial layer. This shows variability in the structure of the tabulates within stromatoporoids. Information is sparse on the range of such variation and assessment of the relative importance of taxonomic, palaeoenvironmental and diagenetic effects is not possible in the present sample. No evidence is found to prove the precise nature of the relationships; they were not parasitic but may have been mutually symbiotic, or (most probably) commensal. The results suggest that the corals selected the most suitable stromatoporoid species for their requirements. Stromatoporoid morphology may have had an important influence on the association, where corals are more abundantly associated with those stromatoporoid species which adopted a high profile. Overall the associations appear to have allowed the corals to explore higher energy habitats otherwise unavailable to their delicate branching structure.
The tabulate coral Pleurodictyum americanum Roemer has been cited as an example of a host-specific organism occurring exclusively on the shells of gastropods, particularly Palaeozygopieura hamiltoniae (Hall). Examination of over 1600 specimens of P. americanum, from the Middle Devonian Hamilton Group of western New York, reveals additional complexities which require reinterpretation. While substrate selectivity for Palaeozygopieura shells is evident in all 42 subsamples, a variety of other substrates were also utilized by Pleurodictyum including corals, brachiopods, other molluscs and pebbles. Recent scleractinian corals inhabiting soft bottoms show similar substrate preference, selecting for the tubes of live serpulids, or gastropod shells (invariably with a secondary sipunculid host), but also occasionally settling on unoccupied shells or pebbles. Shell surfaces of P. hamiltoniae, preserved as external molds on the Pleurodictyum epitheca, exhibit encrustation by worm tubes and bryozoans as well as borings and mechanical shell damage, suggesting that these were not the shells of live gastropods. However, the invariant aperture-downward orientation and the high degree of selectivity of P. americanum strongly suggest that the shells were occupied by secondary hosts. □Substrate specificity, commen-salism, tabulate coral, gastropod, sipunculid, Devonian, Hamilton Group, New York.
The encrusting tentaculitoid tubeworms (Middle Ordovician to Middle Jurassic) have their acme of diversity in the Middle Paleozoic and they form a part of the Paleozoic evolutionary fauna. Most of the morphological and ecological innovations of encrusting tentaculitoid tubeworms appeared during the initial phase of their evolution in the Ordovician and Silurian, and no innovations appeared after the Devonian. The evolutionarily most successful (long lasting) were general hard substrate encrusters, and the most successful morphologies supported this life mode. The morphologies that lasted the longest appeared in the beginning of tentaculitoid tubeworm evolution (during the Ordovician). The ecological innovations with the shortest durations were associated with highly dependent distorting symbiotic and endosymbiotic life modes. Predation pressure may have led to evolution of defensive morphologies (e.g. spines and thick vesicular walls) and endosymbiotic life mode in cornulitids, trypanoporids, Anticalyptraea and Streptindytes.
Tymbochoos sinclairi (Okulitch, 1937) has a laminar tube structure and pseudopuncta similar to the tentaculitoids. This suggests that Tymbochoos belongs to the Tentaculitoidea Boucek, 1964. (c) 2006 Elsevier Masson SAS. All rights reserved.
Cornulitids appeared in the Middle Ordovician, and the earliest repairs to their shells are reported from the Upper Ordovician (Katian) of Baltica and North America (Hirnantian). Shell repair is common in the Silurian (Sheinwoodian) unattached cornulitid Cornulites cellulosus from the Baltica and is interpreted here as a result of failed predation. Scalloped, divoted and embayed type of shell repairs occur in three species of Cornulites. The species with the most repairs, C cellulosus, yielded a shell repair frequency of 20.7% with 29 specimens. There are probable antipredatory adaptations, such as spines and extremely thick vesicular walls, in the morphology of Silurian cornulitids. The morphological and ecological evolution of cornulitids could thus have been partially driven by predation. (C) 2008 Elsevier B.V. All rights reserved.
Commensalism in the narrow sense can be understood as an interaction strictly neutral for one organism and positive for the other. Neutral interaction is the absence of interaction and as such it cannot be proven (the proof of absence cannot be made) and consequently it can be regarded as a concept unfit for empirical science. In the broad sense it is often understood as a weak (positive or negative) interaction on one hand and positive on the other. This approach also seems imperfect, as weak interactions should be regarded rather as mutualism or parasitism, respectively. The borders between interactions (commensalism/parasitism and commensalism/mutualism) are difficult to define; hence commensalism should rather be considered as a theoretical interval within the continuum of interactions. Detection of commensalism in recent associations is rather difficult, while in the fossil record it seems impossible. Commensalism as a null hypothesis in paleoecology cannot be retained, as the possibility of making a type II error is very high. The terms "paroecia" and "endoecia" seem to be more useful to use in cases when a particular ecological relationship is difficult to prove.
Much research has suggested that anxiety is involved in the temporomandibular joint syndrome (TMJ), but it is not clear whether it is a cause or a consequence of the disorder. The present study attempts to resolve this issue. Thirty-two patients suffering from temporomandibular joint syndrome and 32 sex- and age-matched dental clinic controls completed the Spielberger State-Trait Anxiety Inventory, the Eysenck Personality Questionnaire and a standardized inventory of bodily symptomatology. TMJ patients scored significantly higher on Eysenck's neuroticism and introversion scales (both P less than 0.05) and had higher trait anxiety scores (P less than 0.005) when compared with controls. These results suggest that TMJ patients have personalities that are vulnerable to life stresses, but that they are not more anxious than controls at any given time. Such a personality profile is similar to that found in other 'functional' syndrome patient groups, such as individuals with globus pharyngis. We suggest that certain stress prone personalities express anxiety in the form of a predictable set of physical syndromes which may be subject to changes with time.
This study begins to redress our lack of knowledge of the interactions between colonial hosts and their parasites by focusing on a novel host-parasite system. Investigations of freshwater bryozoan populations revealed that infection by myxozoan parasites is widespread. Covert infections were detected in all 5 populations studied and were often at high prevalence while overt infections were observed in only 1. Infections were persistent in populations subject to temporal sampling. Negative effects of infection were identified but virulence was low. Infection did not induce mortality in the environmental conditions studied. However, the production of statoblasts (dormant propagules) was greatly reduced in bryozoans with overt infections in comparison to uninfected bryozoans. Overtly-infected bryozoans also grew more slowly and had low fission rates relative to colonies lacking overt infection. Bryozoans with covert infections were smaller than uninfected bryozoans. High levels of vertical transmission were achieved through colony fission and the infection of statoblasts. Increased fission rates may be a strategy for hosts to escape from parasites but the parasite can also exploit the fragmentation of colonial hosts to gain vertical transmission and dispersal. Our study provides evidence that opportunities and constraints for host-parasite co-evolution can be highly dependent on organismal body plans and that low virulence may be associated with exploitation of colonial hosts by endoparasites.
The importance of ecological interactions in driving the evolution of animals has been the focus of intense debate among paleontologists, evolutionary biologists, and macroecologists. To test whether the intensity of such interactions covaries with the secular evolutionary trend in global biodiversity, we compiled a species-level database of predation intensity, as measured by the frequency of common predation traces (drillings and repair scars ranging in age from Ediacaran to Holocene). The results indicate that the frequency of predation traces increased notably by the Ordovician, and not in the mid-Paleozoic as suggested by multiple previous studies. Importantly, these estimates of predation intensity and global diversity of marine metazoans correlate throughout the Phanerozoic fossil record regardless of corrections and methods applied. This concordance may represent (i) an ecological signal: long-term coupling of diversity and predation; (ii) a diversity-driven diffusion of predatory behaviors: an increased probability of more complex predatory strategies to appear at higher diversity levels; or (iii) a spurious concordance in signal capture: an artifact where rare species and less-frequent (e.g., trace-producing) predatory behaviors are both more detectable at times when sampling improves. The coupling of predation and diversity records suggests that macroevolutionary and macroecological patterns share common causative mechanisms that may reflect either historical processes or sampling artifacts.
• macroecology
• macroevolution
The Seventh Baltic Stratigraphical Conference. Abstracts and Field Guide
- O Hints
- L Ainsaar
- P Männik
Hints, O., Ainsaar, L., Männik, P., Meidla, T. (Eds.), 2008. The Seventh Baltic Stratigraphical
Conference. Abstracts and Field Guide. Geological Society of Estonia, Tallinn, p. 46.
Direct evidence of ancient symbiosis using trace fossils From Evolution to Geobiology: Research Questions Driv-ing Paleontology at the Start of a New Century
- L Tapanila
Tapanila, L., 2008. Direct evidence of ancient symbiosis using trace fossils. In: Kelley, P.H., Bambach, R.K. (Eds.), From Evolution to Geobiology: Research Questions Driv-ing Paleontology at the Start of a New Century, Paleontological Society Short Course, October 4, 2008: Paleontological Society Papers, 14, pp. 271–287.
The Tentaculites of Bohemia. Publication of the Czechoslovakian Academy of Sciences
- B Bouček
Bouček, B., 1964. The Tentaculites of Bohemia. Publication of the Czechoslovakian
Academy of Sciences, Prague. 125 pp.
Parasitism on favositids (Tabulata)
- Zapalski
Zapalski, M.K., 2004. Parasitism on favositids (Tabulata). Palaeontology Newsletter 57, 194.