Dendroid Graptolites Research Articles

Mass occurrence of planktic dendroid graptolite synrhabdosomes (Calyxdendrum) from the Early Ordovician Fezouata biota of Morocco

The genus Calyxdendrum is here revised to include planktic dendroid graptolites from the Ordovician (Tremadocian to Sandbian). The mass occurrence of Calyxdendrum amicabilis n. sp. from the Fezouata biota represents one of the few occurrences of synrhabdosomes of dendroid morphology that have ever been discovered. Composite structures, formed from about four to six slender, conical tubaria of the species appear as umbrella-shaped synrhabdosomes. In these, the individual tubaria are connected by their short nemata forming an irregularly shaped proximal membrane. The species is found in the late Tremadocian Sagenograptus murrayi Biozone of the Bou Izargane section in the Ternata plain north of Zagora, Morocco. The mass occurrence is interpreted to represent planktic dendroid colonies transported by low velocity currents or moving actively into different water regions on a wide shallow shelf region. They settled in the “soupy” soft sediment, where they were subsequently compacted in the now lithified mudstone. Planktic dendroids of the genus Calyxdendrum are so far known exclusively from the peri-Gondwana region, but may prove to show a wider biogeographical distribution when better known.

Unique 3D preservation of Rhuddanian (Silurian) Callograptidae (Gorny Altai, Russia)

We studied a collection of the Silurian (Rhuddanian) multi-branched dendroids, including reticulate, benthic dendroid graptolites of the Callograptidae Hopkinson (in Hopkinson and Lapworth, 1875), from the Gorny Altai, Russia. Species of Dictyonema Hall, Koremagraptus Bulman, Callograptus Hall, and Desmograptus Hopkinson were identified and described. The graptolites are represented by in situ burial of colonies with 3D preservation of tubaria (= rhabdosomes). Complete (intact) colonies of dendroid graptolites are characterized by successive development stages: juvenile, neanic, ephebic (adults), while the general configuration of the tubarium changed from the proximal to distal. In a number of cases, later stage of colony development — the gerontic stage (senilis) is found. We carried out morphological analysis of dendroid graptolite tubaria (Callograptidae) of various development stages, showing eight morphotypes of the colonies, namely, the cylinder, disc, disc on a stem, hemisphere, cone, wineglass, blooming flower, and funnel type.

Stratigraphy of the Cambrian (Miaolingian to Furongian) and Ordovician (Tremadocian) west of Arivechi, eastern Sonora, Mexico: Implications on the Cambrian-Ordovician boundary

The Cambrian-Ordovician transition in Mexico has been poorly documented. According to the literature published until now, the most complete middle-upper Cambrian (Miaolingian to Furongian)-Lower Ordovician (Tremadocian) (509-477 Ma) succession is exposed near the town of Arivechi, in northeastern Sonora. This Cambrian-Ordovician sedimentary succession is approximately 900 m thick and is divided into seven lithostratigraphic units. The Cambrian portion of the section consists of El Gavilán, El Mogallón, Milpillas, and La Huerta formations (∼600 m) and range from the upper Wuliuan to Paiban stages (509-494 Ma). El Gavilán Formation consists of limestone and shale with chancelloriids and trilobites of the Altiocculus Subzone of the upper Ehmaniella Zone (Miaolingian, Wuliuan). El Mogallón formation (informal name) is characterized by shale, siltstone, and limestone with abundant poriferans and agnostids of the Ptychagnostus atavus/Bolaspidella Zone (Miaolingian, Drumian). Milpillas formation (informal name) consists of limestone and sandy limestone with trilobites of the Crepicephalus Zone (Miaolingian, Guzhangian). La Huerta formation (informal name) is a limestone and shale intercalations with abundant brachiopods, including Angulotreta triangularis, indicative from the Aphelaspis to the lower Dunderbergia Zones (Furongian, Paibian). The Lower Ordovician (Tremadocian) portion of the section consists of El Santísimo formation herein informaly divided into three members: El Ranchito, El Encinal and La Palma (∼300 m). El Ranchito member consists of limestone, shale, and siltstone with dendroid graptolites of Anisograptus matanensis Zone (Early Ordovician, Tremadocian). El Encinal member consists of siltstone and sandstone with cross-stratification and graptolites of Anisograptus matanensis Zone (Early Ordovician, Tremadocian). La Palma member contains in the lower non-fossiliferous part, a limestone breccia and siltstone, and the upper part contains limestone with conodonts from the Rossodus manitouensis to the Scolopodus subrex Zone (Early Ordovician, Tremadocian). The Cambrian deposits of eastern Arivechi represent open marine platform facies with an abundant fauna of poriferans, brachiopods, trilobites, and echinoderms, typical of Laurentia. In contrast, the Ordovician deposits represent open ocean deposits dominated by graptolites and conodonts that indicate a shallow marine to a shelf environment.

Regional overprint of the GOBE: Dendroid graptolites reveal palaeoecological bias

Dendroids have palaeoecological potential but are underrated in general. The present study is focused on the interval from the Floian to the earliest Sandbian (Klabava, Šárka and Dobrotivá formations) in the Ordovician of the Prague Basin (Czech Republic). It is based especially on the new datasets of all dendroid graptolites from the Šárka and Dobrotivá formations at our disposal combined with the data of the overall biodiversity in the studied interval. The analysis of diversity illustrates that there is a remarkable contrast in the studied period: dendroids declined when other groups flourished and the diversity in the Prague Basin reached the first of the two Ordovician maxima coeval with the GOBE. The patterns of those shifts seem to be primarily influenced by local environmental changes, i.e. ecologically controlled in the Prague Basin. The decline of dendroid graptolites was apparently caused by the disappearance of habitats, represented by proper substrate in the oxygenated environment, due to a gradual but continuing sea level rise. Our case study resulted in the distribution model providing a general example of local factors masking those global and exemplifying a significance of differentiation between global and local causes of the GOBE.

Benthic graptolites from the Lower Silurian of the Western Sayan

Dendroid graptolites of the Ona Formation from Lower Silurian of the Western Sayan have been studied. The collection is represented by very well preserved specimens. It includes only benthic forms and is characterized by the complete absence of planktonic taxa. This is extremely rare for graptolite communities. Representatives of dendroid graptolites have retained their lifetime shape. The unbroken shape of rhabdosomes may indicate calm sedimentation environments, since it is benthic dendroid graptolites that are very easily destroyed by underwater currents. Such type of autochthonous burial was previously studied by the authors on the territory of the Gorny Altai, and it is also known in the Lower Silurian of the Czech Republic.

Late Ordovician (Katian) Graptolites and Shelly Fauna from the Phu Ngu Formation, North-East Vietnam

Two new graptolite assemblages are identified from discrete intervals within the Phu Ngu Formation, Na Ri District, Bac Kan Province, north-east Vietnam. The graptolites occur in laminated mud/siltstones thought to be distal turbidite deposits. A low-diversity diplograptid sensu lato assemblage occurs in mud-rich layers that are interlaminated with silty and sandy horizons containing the dendroid graptolite Dictyonema sp. This level also contains orthoconic nautiloids and conulariids. A few metres stratigraphically above, a second more diverse graptolite assemblage comprises a single Dicellograptus, tentatively identified as D. flexuosus, together with Climacograptus dorotheus and Orthograptus truncatus pauperatus in mud and silt laminae that also yield brachiopods, orthoconic nautiloids, conulariids, fragmentary trilobites, and ostracods. The ostracods include the first East Asian occurrence of the typically Baltic genus Kinnekullea, and we describe the new species Kinnekullea gaia. The graptolites suggest a Late Ordovician Katian age, most probably in the Dicranograptus clingani Biozone, this being older than previous biostratigraphical constraints on the Phu Ngu Formation.

Devonian and Carboniferous dendroid graptolites from Belgium and their significance for the taxonomy of the Dendroidea

Devonian and Carboniferous dendroid graptolites from Belgium are evaluated and partly revised. New finds in two different stratigraphic intervals of the ‘Carrière de Lompret’, an active quarry exploiting Frasnian limestones and shales east of Frasnes-lez-Couvin, allow the identification of Callograptus sp. and Dictyonema fraiponti, both belonging to the dendroid family Acanthograptidae. The relatively high diversity of the dendroid graptolite fauna from the Viséan Marbre noir de Denée, one of the few Carboniferous graptolite faunas in the world, can be shown to be based on astogenetic and preservational aspects. Nearly all known specimens can be included in the highly variable Dictyonema fraiponti, a fan-shaped large dendroid species with complex stipes formed from tubular thecae, possessing simple to complex bridges connecting adjacent stipes. Some of the graptolite material is well preserved and provides important information on the tubarium construction of Devonian to Carboniferous dendroid graptolites and, thus, is highly significant for a taxonomic and phylogenetic understanding of the youngest dendroid graptolite faunas worldwide. The genera Callograptus and Ptiograptus are revised based on their type species (Callograptus elegans from Quebec, Canada; Ptiograptus percorrugatus from the Silurian or Devonian of Kentucky, USA) and referred to the Acanthograptidae.

Mid-Furongian trilobites and agnostids from theWujiajiania lyndasmithaeSubzone of theElviniaZone, McKay Group, southeastern British Columbia, Canada

AbstractA well-preserved fauna of largely articulated trilobites is described from three new localities close to one another in the Bull River Valley, southeastern British Columbia. All the trilobites from these localities are from the lower or middle part of theWujiajiania lyndasmithaeSubzone of theElviniaZone, lower Jiangshanian, in the McKay Group. Two new species are proposed with types from these localities:Aciculolenus askewiandCliffia nicoleae. The trilobite (and agnostid) fauna from these localities includes at least 20 species:Aciculolenus askewin. sp.,Agnostotes orientalis(Kobayashi, 1935),Cernuolimbus ludvigseniChatterton and Gibb, 2016,Cliffia nicoleaen. sp.,Elvinia roemeri(Shumard, 1861),Grandagnostus? species 1 of Chatterton and Gibb, 2016,Eugonocare?phillipiChatterton and Gibb, 2016,Eugonocare? sp. A,Housia vacuna(Walcott, 1912),Irvingella convexa(Kobayashi, 1935),Irvingella flohriResser, 1942,Irvingellaspecies B Chatterton and Gibb, 2016,Olenaspella chrisnewiChatterton and Gibb, 2016,Proceratopyge canadensis(Chatterton and Ludvigsen, 1998),Proceratopyge rectispinata(Troedsson, 1937),Pseudagnostuscf.P. josepha(Hall, 1863),Pseudagnostus securiger(Lake, 1906),Pseudeugonocare bispinatum(Kobayashi, 1962),Pterocephaliasp., andWujiajiania lyndasmithaeChatterton and Gibb, 2016.Pseudagnostus securiger, a widespread early Jiangshanian species, has not been previously recorded from southeastern British Columbia. Non-trilobite fossils collected from these localities include brachiopods, rare trace fossils, a complete silica sponge (Hyalospongea), and a dendroid graptolite. The faunas from these localities are more diverse and better preserved than those from other previously documented localities of the same age in the region.Additional specimens of a rare species, found by amateur collectors in previously documented localities of slightly younger age (upper part ofWujiajiania lyndasmithaeSubzone) in the same region, are documented. These new specimens, when combined with an earlier discovered specimen, provide adequate type material to propose a new species ofLabiostria, L. gibbae, which may be useful for biostratigraphy.UUID:http://zoobank.org/89551eac-b3af-4b2b-8ef3-7c2e106a560d

The hydroid fossil record and analytical techniques for assessing the affinities of putative hydrozoans and possible hemichordates

AbstractHydrozoan cnidarians are widespread in modern environments, but their polyps or hydroids, when not biomineralized, are generally rare in the fossil record. To assess the affinities of four hydrozoan taxa previously described on the basis of supposed fossils of non‐biomineralized hydroids, we re‐analysed the type specimens of these taxa using a combination of light and electron microscopic tools, including backscattered electron (BSE) scanning electron microscopy (SEM) and energy‐dispersive X‐ray spectroscopy (EDS). New morphological, ultrastructural and taphonomic data were generated for Archaeoantennularia byersi from the Devonian of Michigan, Archaeocryptolaria compacta from the Ordovician of Virginia, and Mazohydra megabertha and Drevotella proteana from the Carboniferous Mazon Creek Lagerstätte of Illinois, which are preserved as carbonaceous fossils, aluminosilicate films and iron carbonate minerals in siderite concretions, respectively. In the context of these results, we provide a review of the fossil record of non‐biomineralized hydroids, describe possible biases and changes through time in their occurrence and preservation, and evaluate the criteria commonly used to identify and interpret their fossils. Although hydroids have been reported from Phanerozoic (particularly lower Palaeozoic) rocks around the world, many putative hydroids from the Palaeozoic are poorly substantiated and may actually be hemichordates. Indeed, none of the type specimens in this study represent unequivocal hydrozoans. As shown in BSE images, metatype specimens of A. byersi possess autothecae, fusellae, stolons, stolothecae and bithecae, which decisively indicate that they are dendroid graptolites rather than hydroids. The analyses yielded no evidence that A. compacta, Mazohydra and Drevotella are hydrozoans, as their holotypes lack the diagnostic morphological, taphonomic and ecological features characteristic of purported hydroid analogues. Consequently, our results suggest that many Palaeozoic hydroids may be hemichordates and that interpretations of hydroid fossils should be tested and refined using data collected via in situ analytical techniques like BSE‐SEM and EDS.

Taxonomic and biostratigraphic reappraisal of some early Tremadocian (Ordovician) graptolites from Changde, South China

A diverse fauna of dendroid graptolites and graptoloids occurs in the Tremadocian Madaoyu Formation of the Panjiazui section, near Changde, Hunan Province, South China. The dendroids are Callograptus cylindricus, C. ellipsoideus, C. isolateralis, C. salteri, C. suxianensis, C. taitzehoensis, and Dendrograptus yini; the graptoloids are Anisograptus delicatulus, Anisograptus sp., Adelograptus sp., Staurograptus cf. mojotorensis, Rhabdinopora flabelliformis anglica, R. umbellata, Rhabdinopora sp. 1, and Rhabdinopora sp. 2. All taxa are figured and the selected graptoloid taxa are described. Based on this taxonomic revision, the Tremadocian Rhabdinopora flabelliformis anglica and Adelograptus biozones are recognized in the Panjiazui section, allowing correlation with other graptolitic successions worldwide.

The early Ludfordianleintwardinensisgraptolite Event and the Gorstian-Ludfordian boundary in Bohemia (Silurian, Czech Republic)

The late Gorstian to early Ludfordian hemipela- gic succession of the south-eastern part of the Prague Syn- form preserves a rich fossil record dominated by 28 species of planktic graptoloids associated with pelagic myodocopid ostracods, pelagic and nektobenthic orthocerid cephalopods, epibyssate bivalves, nektonic phyllocarids, rare dendroid graptolites, brachiopods, crinoids, trilobites, sponges and macroalgae. Faunal dynamics have been studied with parti- cular reference to graptolites. The early Ludfordian leintwar- dinensis graptolite extinction Event manifests itself as a stepwise turnover of a moderate diversity graptolite fauna rather than an abrupt destruction of a flourishing biota. The simultaneous extinction of the spinose saetograptids Saeto- graptus clavulus, Saetograptus leintwardinensis and the rare S. sp. B. at the top of the S. leintwardinensis Zone was preceded by a short-term acme of S. clavulus. Cucullograptus cf. aver- sus and C. rostratus vanished from the fossil record in the lower part of the Bohemograptus tenuis Biozone. No mass proliferation of Bohemograptus has been observed in the postextinction interval. Limited indigenous speciation gave rise to Pseudomonoclimacis kosoviensis and Pseudomonoclima- cis cf. dalejensis. Egregiograptus (the only novel element of cryptic origin) made its earliest occurrence in association with the latest cucullograptids. A postextinction graptolite assemblage of moderate diversity, composed for the most part of long-ranging taxa, persisted through the middle and upper tenuis Biozone until new rediversification in the Neo- cucullograptus inexpectatus Biozone. Unlike the graptoloids, the planktic, epiplanktic, nektonic and nektobenthic shelly fauna did not suffer significant extinction in the early Lud- fordian. The Gorstian-Ludfordian boundary is placed at the lowest occurrence of S. leintwardinensis in spite of the very modest graptolite record available from the Ludfordian GSSP where no graptolites occur below the basal bed of the Lower Leintwardine Formation. Elsewhere, the Gorstian-Ludfordian boundary has been placed at the base of the Saetograptus linearis Biozone which has been considered roughly correla- tive with the leintwardinensis Biozone. Indeed, our morpho- metric study places the worldwide biozonal index species S. linearis in synonymy with S. leintwardinensis and thus considerably enhances the biostratigraphical utility of the lat- ter index species. Pseudomonoclimacis antiqua sp. nov. is described.

Dendroid graptolites from the Lower Ordovician (Tremadocian) of the Yichang area, Hubei, China

The Yichang area of Hubei Province, China provides important information on Lower to Middle Ordovician fossil faunas and is a center for research on Ordovician graptolites due to the sometimes excellent preservation of the copiously available material. New material collected during a research project on Lower to Middle Ordovician biota in the Yichang Region provided among others specimens a number of dendroid (benthic) graptolites of the genera Acanthograptus, Aspidograptus, Dendrograptus, and Koremagraptus showing unexpected and unknown structural features, useful for structural and evolutionary investigations.

Sagenograptoides, a new name for the retiolitid graptolite Sagenograptus Lenz and Kozłowska-Dawidziuk, 2001

In 2001, Lenz and Kozłowska-Dawidziuk assigned the name Sagenograptus (species name S. arctos) to a late Wenlock retiolitid graptolite from Arctic Canada. We thank Rimma Sobolevskaya for subsequently informing us that the name Sagenograptus (species S. gagarini) had, already in 1962, been applied by Obut and Sobolevskaya to a Tremadoc dendroid graptolite from Taimyr. The generic name for the Arctic Wenlock retiolitid is here changed to Sagenograptoides.

The Ultrastructure and Building of Graptolite Dissepiments

Dissepiments or connecting bars between adjacent stipes in rhabdosomes of dendroid graptolites were studied by means of electron microscopy (SEM and TEM). The material, chemically isolated from rock matrix, originating from the Ordovician of Estonia and glacial boulders of Baltic origin found in Poland, is assigned provisionally to the genus “Dictyonema” sensu lato. Early growth stages of dissepiments are made only of the fusellar component. Older dissepiments are composed of the central core and the outer envelope: the central core is made of rather irregularly arranged growth units made of the fusellar tissue, whereas the outer envelope has a distinct cortical appearance. TEM observations indicate that the fusellar component is made of both typical fusellar and microfusellar tissues (the latter with complete and reduced microfuselli). The cortical component of dissepiments is made both of dependent and independent cortex. The opinion is advanced that the dissepiments were constructed externally by the m...

An Upper Llandovery Konservat–Lagerstätte in a depositional context: the Pentland Hills Eurypterid Bed, Midlothian

Synopsis Re-excavation and detailed logging of the sedimentary sequence which includes the Eurypterid Bed on the Gutterford Burn, Pentland Hills, Midlothian, has clarified the depositional setting of this Silurian Konservat–Lagerstätte. The relative positions of the Gutterford Burn limestones, beds yielding dendroid graptolites and the Eurypterid Bed itself have been identified. Clay bands occur at a number of horizons throughout the 23 m of logged section, but the most important of these enclose the distinctive lithology of the Eurypterid Bed. Exceptionally preserved fossils typically occur within a volcanic ash-rich claystone which was deposited below storm wave-base in a fully marine setting. Depositional style, presence of in situ corals and the presence of volcaniclastic input all indicate similarity to the sequence exposed around the Deerhope Coral Beds. The stratigraphy of the North Esk Inlier is revised t o take into account these new findings. The boundary between the Reservoir Formation and the overlying Deerhope Burn Formation is defined as lying at the base of the first calcareous sandstone on the Gutterford Burn section.

Middle Devonian dendroid graptolites from the Brilon Reef area (Rheinisches Schiefergebirge, Germany)

Dendroid graptolites from the Middle Devonian (Givetian, middlePolygnathus varcus Biozone) of the Rheinisches Schiefergebirge are described for the first time. The fauna of the Burgberg locality south of the Brilon reef comes from a black shale layer in a succession of calcareous debris flows. The fauna includes five species ofDictyonema andRuedemannograptus described in open nomenclature. The fragmentation of the material is conside-red as an indication of post-mortem transport.

Middle Cambrian pterobranchs and the Question: What is a graptolite?

The presence of distinct fusellar structure is taken as evidence to include a number of fossils from the Middle Cambrian to the Lower Ordovician of North America and Europe with the Pterobranchia. The dome of the pterobranchs and the prosicula of the planktic graptolites are contrasted and evidence is given for the re-assignment of a number of well known dendroid graptolites to the pterobranchs. A non-destructive method is described to reveal fusellar development of delicate hemichordate exoskeletons from shales. Rhabdotubus robustus n. sp. from the Czech Republic and ? Cephalodiscus sp. from the Wheeler Shale of North America are described as new Middle Cambrian pterobranchs.

Astogenetic aspects of the dendroid graptolite Airograptus (Late Cambrian‐Early Ordovician) and their phylogenetic implications

Based on a Backscatter Electron (BSE) examination of partially 3-dimensional graptolite specimens of Airograptus from the Tremadocian (Early Ordovician) Yehli Formation at Dayangcha, Baishan of Jilin Province, NE China, the thecal structure and astogenetic aspects of this genus (except for the missing proximal part) are described and illustrated in detail. In the present collection, no furcating but only peltate thecal apertural processes are confirmed. A comparison between the presumably benthic dendroid Airograptus and Rhabdinopora, the earliest planktonic graptolite, indicates that there are remarkable similarities in astogenetic aspects between them, although there are also differences in the development of dissepiments and thecal apertural processes. A possible ancestor-descendent relationship between the two genera is herein proposed.

THE OLDEST-KNOWN METAZOAN PARASITE?

A unique specimen of the micromorphic fossil lingulate (organophosphatic-shelled) brachiopod Linnarssonia constans Koneva, 1983 from the late Lower Cambrian Shabakty Group of the Malyi Karatau Range in Kazakhstan, Central Asia, preserves evidence of infestation within the mantle cavity by a vermiform animal, leading to the growth of an internal tubular protuberance (Fig. 1) resulting from symbiosis some 520 million years ago. Examples of symbiotic relationships between metazoans in the early Paleozoic are sparse (Conway Morris, 1981, 1990; Conway Morris and Crompton, 1982). Descriptions of a variety of galls and tumorlike swellings in some trilobites extend records back to the Middle Cambrian (Conway Morris, 1990), but their interpretation as traces of endoparasitic activity remains somewhat speculative. Thus galllike swellings on the stems of Silurian echinoderms (Franzen, 1974), vermiform tubes on some early Ordovician dendroid graptolites (Conway Morris, 1990), and various tubes and blisters on graptoloid graptolites (see Bates and Loydell, 2000 for review) are among the hitherto earliest known convincing records of host-parasite relationships within metazoans. Our example reported here predates the oldest of these previous records by approximately 35 to 40 million years, and demonstrates that symbiosis involving complex adaptations (e.g., larval settlement on or within living tissue and exploitation of feeding systems of the host) and codependent life cycles were already established soon after the ‘explosive’ evolutionary radiation of marine metazoans in the early Cambrian. The fossil evidence of infestation on lophophorates is especially sparse, at best. The oldest hitherto undoubted records are both from brachiopods of Devonian age, in the Lower Devonian Emsian Stage of eastern Australia and in the Middle Devonian Givetian Stage of the Holy Cross Mountains in Poland, respectively.

The oldest-known metazoan parasite?

A unique specimen of the micromorphic fossil lingulate (organophosphatic-shelled) brachiopod Linnarssonia constans Koneva, 1983 from the late Lower Cambrian Shabakty Group of the Malyi Karatau Range in Kazakhstan, Central Asia, preserves evidence of infestation within the mantle cavity by a vermiform animal, leading to the growth of an internal tubular protuberance (Fig. 1) resulting from symbiosis some 520 million years ago. Examples of symbiotic relationships between metazoans in the early Paleozoic are sparse (Conway Morris, 1981, 1990; Conway Morris and Crompton, 1982). Descriptions of a variety of galls and tumorlike swellings in some trilobites extend records back to the Middle Cambrian (Conway Morris, 1990), but their interpretation as traces of endoparasitic activity remains somewhat speculative. Thus galllike swellings on the stems of Silurian echinoderms (Franzen, 1974), vermiform tubes on some early Ordovician dendroid graptolites (Conway Morris, 1990), and various tubes and blisters on graptoloid graptolites (see Bates and Loydell, 2000 for review) are among the hitherto earliest known convincing records of host-parasite relationships within metazoans. Our example reported here predates the oldest of these previous records by approximately 35 to 40 million years, and demonstrates that symbiosis involving complex adaptations (e.g., larval settlement on or within living tissue and exploitation of feeding systems of the host) and codependent life cycles were already established soon after the ‘explosive’ evolutionary radiation of marine metazoans in the early Cambrian. The fossil evidence of infestation on lophophorates is especially sparse, at best. The oldest hitherto undoubted records are both from brachiopods of Devonian age, in the Lower Devonian Emsian Stage of eastern Australia and in the Middle Devonian Givetian Stage of the Holy Cross Mountains in Poland, respectively.