Echinoderm Fauna Research Articles

Impact of river discharge and suspended sediments on the nearshore benthic environment along the Indian southwest coast

River discharge into the sea and its implications on the environmental setting and fauna in the nearshore represent the intricate interactions among the atmosphere, hydrosphere, lithosphere, and biosphere. This study, based on in-situ and satellite data, presents how spatially varying river discharge laden with suspended sediments structure the hydrography and the nearshore benthic environment over a 590 km southwest (Kerala) coast of India. The 41 rivers that discharge along the Kerala coast are monsoon-driven; they are small but swift and cumulatively supply huge amounts of freshwater and suspended sediments into the Southeastern Arabian Sea (SEAS) during the Southwest Monsoon (SWM) when around 70 % (1925 mm) of the yearly rainfall occurs. These rivers are distributed unevenly along the coastline, with twenty-four of them discharging in the northern region (10.9–12.5°N), nine in the central (9.2–10.9°N), and eight in the south (8–9.2°N). During the SWM, plumes of low salinity (<32) with high clay content were widespread in the northern and central regions of the study area due to heavy river discharge and the presence of crystalline rocks and laterite deposits. In contrast, the low salinity plumes and suspended sediments were markedly low in the southern region due to limited river discharge and a predominance of sedimentary rocks and coastal alluvium that supported sandy sediments. This resulted in a spatial change in benthic sediment texture as well, with the central and northern regions more silty or clayey, while the south was sandy. Interestingly, the sandy south section had a noticeably higher faunal abundance than the rest of the region with an increased abundance of sensitive fauna of molluscs and echinoderms. This is a clear case of how spatially varying river discharge and sediment flux impact the nearshore environment and fauna.

Silurian Diploporitans as Substrata:

The middle Silurian Massie Formation of southeastern Indiana contains a rich stalked echinoderm fauna, of which diploporitan “cystoids” are a significant component. A small number of diploporitan thecae are encrusted by the dendritic radicular attachment structures of the monobathrid camerate crinoid Eucalyptocrinites. Recently, several encrusted specimens of the diploporitan Holocystites scutellatus were described from the Massie Formation of the Napoleon quarry (Ripley County) that are unusual in that the encrusting holdfasts display pronounced asymmetry with respect to radicle development. Due to settlement near the margin of the thecae, long, well-developed radicles are present on the side of the attachment structure where they could extend over the entire lateral surface of the theca, and short, poorly developed radicles are present on the side facing the margin of the theca. The anomalous nature of this attachment structure morphology is herein highlighted by comparison to more typical Eucalyptocrinites-encrusted diploporitan thecae from the same locality and stratigraphic interval. These display a much more radially symmetrical configuration of radicles due to a more central settlement position on the thecal lateral surface. Several additional morphological and paleoecological aspects of crinoid encrustation of diploporitans are described and illustrated, including an apparently bilaterally symmetrical radicle growth pattern and a rare occurrence of an encrusted Paulicystis.

Diversity, distribution patterns and indicatory potential of echinoderm communities of the tropical East Atlantic (Gulf of Guinea): Influence of multiple natural and anthropogenic factors along a 25–1000 m depth gradient

All earlier studies of the West African echinoderm fauna have focused on taxonomy, and general knowledge about benthic community responses to various human related threats are poorly diagnosed and not monitored along the whole African coast. Our analysis of diversity and distribution patterns of Ghanaian echinoderms yielded 36 species. Material was collected at nine transects distributed along the coast of Ghana (25–1000 m depth range, total of over 270 samples). Gradual decreases in species richness, diversity, evenness and abundance were observed along the depth gradient, with the most diverse fauna being recorded on the shelf (25–50 m). The most abundant species were Ophiactis luetkeni and Ophiothrix congensis, although both had very patchy distributions. Cluster analysis separated shelf communities (25–100 m) from slope communities (500–1000 m), although on a low level of similarity. Our analysis allowed to select most vulnerable benthic habitats that should be amongst priorities of the future monitoring. Local influence of arsenic was observed at some shelf sites, while slope fauna was affected by elevated levels of hydrocarbons and barium. Changes in salinity and fluorescence also influenced echinoderm assemblages. The most general trend showed patchily distributed, diverse shallow water fauna being influenced by increased microhabitat diversity and food availability, while depauperate slope fauna was affected by local disturbances associated with oil extraction. Tropical echinoderm communities have a great potential as indicators of even minor and local pollution, although high patchiness and low abundance creates difficulties in the multivariate analysis. High sampling effort and high number of replicates allowed to minimise those problems and demonstrated small scale microhabitat diversity.

A Silurian (Homerian) pelmatozoan echinoderm fauna from west-central Ohio, USA

AbstractA diverse echinoderm fauna lived in reef and non-reef Silurian facies of the upper Midwestern USA. However, these faunas are dominantly preserved in dolostones with moldic preservation, and fossils from dolostone facies have not been documented to the extent of Silurian crinoids in nondolostone strata. Herein, an echinoderm fauna is described from the dolostones of the Cedarville Member of the Laurel Limestone (Wenlock, Homerian) from the Pepcon Cement Quarry in west-central Ohio. The described fauna contains blastoids, hemicosmitoids, and crinoids, including Troosticrinus subcylindricus (Hall and Whitfield, 1875); Caryocrinites sp. indet.; an unidentifiable diplobathrid camerate; Periechocrinus tennesseensis (Hall and Whitfield, 1875); Periechocrinus egani? (Miller, 1881); Stiptocrinus farringtoni (Slocom, 1908); Calliocrinus primibrachialis Busch, 1943; Calliocrinus poepplemani new species; Calliocrinus hadros new species; and Lecanocrinus sp. indet. Generic concepts for the Eucalyptocrinitidae are clarified; and, surprisingly, Eucalyptocrinites Goldfuss, 1831 is absent from this fauna. Additionally, lectotypes and paralectotypes are designated for Periechocrinus tennesseensis and Calliocrinus primibrachialis.UUID: http://zoobank.org/a8c8e7e3-9bc3-4078-83bd-5572816366e5

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.

MIDDLE TRIASSIC ECHINODERMS FROM THE SAN SALVATORE FORMATION OF LOMBARDY (ITALY) AND CANTON TICINO (SWITZERLAND)

An echinoderm fauna from the San Salvatore Formation (Middle Triassic, Southern Alps) is here described in detail for the first time. Identifiable crinoids and echinoids were collected from three different localities: Mt. San Salvatore (Ticino, Switzerland), Rasa di Varese and San Michele (Lombardy, Italy). Crinoid taxa include Encrinus cf. aculeatus, Holocrinus sp. indet., Zardinicrinus cf. granulosus, Encrinidae gen. et sp. indet. Echinoid taxa include “Cidaris” cf. roemeri, Serpianotiaris sp. indet., Triadocidaris transversa, Triadocidaris sp. indet., and an indetermined form (Cidaridae). Most of the material was collected from Rasa di Varese, along with a rich upper Anisian ammonoid and conodont fauna, belonging to the upper Reitzi Zone and the Secedensis Zone. Migration of crinoids have been documented during the upper Anisian (from upper Pelsonian to lower Illyrian), mainly from the westernmost Tethyan Realm northward to the Germanic basin. Crinoid taxa already reported in the lower and upper Illyrian of the Germanic basin have also been collected, dated here to the late Illyrian (upper Reitzi Z.-Secedensis Z.) suggesting that several taxa migrated southwards in the Tethys realm during the late Illyrian.

Structural and Functional Insights into the Roles of Potential Metal-Binding Sites in Apostichopus japonicus Ferritin.

Ferritin is widely acknowledged as a conservative iron storage protein found in almost all living kingdoms. Apostichopus japonicus (Selenka) is among the oldest echinoderm fauna and has unique regenerative potential, but the catalytic mechanism of iron oxidation in A. japonicus ferritin (AjFER) remains elusive. We previously identified several potential metal-binding sites at the ferroxidase center, the three- and four-fold channels in AjFER. Herein, we prepared AjFER, AjFER-E25A/E60A/E105A, AjFER-D129A/E132A, and AjFER-E168A mutants, investigated their structures, and functionally characterized these ferritins with respect to Fe2+ uptake using X-ray techniques together with biochemical analytical methods. A crystallographic model of the AjFER-D129A/E132A mutant, which was solved to a resolution of 1.98 Å, suggested that the substitutions had a significant influence on the quaternary structure of the three-fold channel compared to that of AjFER. The structures of these ferritins in solution were determined based on the molecular envelopes of AjFER and its variants by small-angle X-ray scattering, and the structures were almost consistent with the characteristics of well-folded and globular-shaped proteins. Comparative biochemical analyses indicated that site-directed mutagenesis of metal-binding sites in AjFER presented relatively low rates of iron oxidation and thermostability, as well as weak iron-binding affinity, suggesting that these potential metal-binding sites play critical roles in the catalytic activity of ferritin. These findings provide profound insight into the structure-function relationships related to marine invertebrate ferritins.

Current knowledge of echinoderms (Echinodermata) from the coast of Paraíba, northeastern Brazil

The first record of echinoderms from the state of Paraíba appeared in 1789, yet the systematic survey of the phylum along the coast only began in 2008. New species and several new records have been added since. An extensive literature survey and an analysis of the main Echinodermata collections housed in Brazil yielded 74 species. Our qualitative survey results in up-to-date records of echinoderm species along the littoral of the state, including information on habitat and their occurrence in Conservation Units (UCs). Even though all records are from the intertidal to 35 m,the resulting diversity of species is high when compared to other areas, since it corresponds to 21% of all Brazilian species and to 16% of the species known from the Caribbean Sea. The main habitats used by echinoderms are reefs and rhodolith beds. About 15% of the species are in the Brazilian Red List. A positive result is that 67% of these species occur within UCs in the state. Based on these results, we conclude that the fauna of echinoderms from shallow water is well documented in Paraíba. Finally, we comment on the conservation status of species and indicate futuredirections for the study of Echinodermata.

Distribution and Diversity of Echinoderms in the Coastal Waters of South Beach of Lombok Island

Echinoderms are benthic animals that can be found in almost all marine ecosystems but are mostly found in the intertidal coastal zone. Echinoderms play an important role as deposit feeders. This study aims to look at the distribution patterns, diversity, and habitat conditions of species in the southern coastal waters of Lombok Island, namely Kute, Awang, and Gerupuk beaches. The field survey was conducted using the quadratic transect method and free collection in October - November 2020. Based on the results of the research, a total of 11 species of echinoderms were found in Lombok Island consisting of 4 classes. Diadema setosum and Tripneusteus gratila were the most common species, whereas Synapta maculate, Holothuria leucospilota, Echinotrix diadema, Holothuria atra, and Ophiocoma scolopendrina were found in small numbers with uniform distribution (Id &lt;1). Diadema setosum distribution pattern has the highest abundance with a clustered distribution pattern (Id&gt; 1) in Awang and Gerupuk, and Tripneusteus gratila in Kute and Awang. The Diversity Index value is different in each habitat. The highest Shannon-Wiener Diversity Index (Hꞌ) was found in Gerupuk 2.18. The largest smoothing index is found at Awang 0.96. The largest Dominance Index (D) is found in Gerupuk 0.88. Based on the value of the Echinoderm community structure on the South Coast of Lombok Island, it shows that diversity is moderate, community uniformity is unstable, and dominance is low. information regarding the distribution and diversity of Echinoderm fauna in various types of habitats around the seagrass as a first step to anticipate the decline in the Echinoderm population in the waters of the South Coast of Lombok Island.

An Upper Mississippian echinoderm microfauna from the Genicera Formation of northern León (Carboniferous, Cantabrian Mountains, N Spain)

For the first time an echinoderm microfauna is recorded from the cephalopod limestone facies (‘griotte facies’) of the lower Carboniferous (Mississippian) Genicera Fm. (Alba Fm.). The formation is widespread in the Cantabrian Mountains in NW Spain, but the ossicles are from some sections in the surroundings of the Bernesga valley in northern León. They have been derived from insoluble acetic acid residues from samples of the upper and especially of the uppermost part of the formation (Canalón Mb. and Millaró Beds). The microfauna include taxonomically treated wheel-shaped ossicles, sieve-plates and rods of holothurians, goniodonts of ophiocistioids, and ophiuroid and stenuroid skeletal elements. From the Palaeozoic of Spain, Ophiocistioidea, Stenuroidea, Apodida (Holothuroidea), and allagecrinids (microcrinoids) are first reported. Here, we describe two new species: Linguaserra heidii n. sp. (Ophiocistioidea) and Calclyra bifida n. sp. (Ophiuroidea). Indeterminate echinoderm remains are also figured and discussed. The findings stress the importance of a diverse but still poorly documented echinoderm fauna in Upper Mississippian psychrospheric pelagic environments.

New species and occurrence records of Japanese Solasteridae and Ganeriidae including a new species of Paralophaster from the North Pacific with an overview of Hyalinothrix.

Japanese waters contain a highly diverse echinoderm fauna including many undiscovered species, especially in deeper-water settings. Molecular phylogenetic data has shown a close relationship between three established families of asteroids, the Asterinidae, the Solasteridae and the Ganeriidae, which are three groups that are well-represented in the region. We present two undescribed species of solasterids, Lophaster cactorum n. sp. and Paralophaster gomo n. sp., the latter represents a genus which had previously been known primarily from Antarctic settings. New occurrence records of the tropical deep-sea Pacific solasterid Rhipidaster vannipes Sladen, 1889 has led to synonymy of Xenorias polyctenius Fisher, 1913. Three undescribed species of Hyalinothrix, Hyalinothrix diversus n. sp., Hyaliothrix enoki n. sp. and Hyalinothrix virtrispinum n. sp. are described. Nepanthia grangei McKnight, 2001 is transferred to Hyalinothrix. A new subfamily, the Hyalinothricinae is established within the Asterinidae, including Tarachaster and Seriaster, which was formerly assigned to the Solasteridae. Knightaster is reassigned to the Asterinidae from the Ganeriidae.

Revised stratigraphy of the middle Simcoe Group (Ordovician, upper Sandbian–Katian) in its type area: an integrated approach

The Upper Ordovician Bobcaygeon Formation of southern Ontario is a widespread unit that spans the Sandbian–Katian stage boundary and contains exceptionally preserved invertebrate fossil assemblages, including the famed ‘Kirkfield echinoderm fauna.’ However, the precise correlation of this interval remains poorly understood. This paper presents new data on high-resolution sequence and carbon isotope chemostratigraphy of the Bobcaygeon interval based on new quarry exposures and introduces refined definitions of unit boundaries based on allostratigraphic criteria. Sequence, chemo-, and biostratigraphic evidence indicate that the Bobcaygeon Formation represents a composite unit as it encompasses a major erosional unconformity. The Coboconk and Kirkfield formations, described in the early 20th century, were merged into a single unit, the Bobcaygeon, out of concern that the original lithostratigraphic divisions would be conflated with biostratigraphic zones of the same names. However, these biostratigraphic zones are no longer favoured, and the lower member of the Bobcaygeon is here elevated again to the status of formation (Coboconk Formation) and represents the uppermost portion of the Sandbian M4 sequence. The middle and upper members of the Bobcaygeon, herein reassigned to the Kirkfield Formation, represent the upper Sandbian to lower Katian M5A and M5B sequences recognized widely in the eastern and central United States. The term Bobcaygeon is retained and elevated to the rank of subgroup. The Kirkfield Formation is divided into three members and contacts are refined, placing a 1–2 m transgressive grainstone at the base of each sequence. These units are correlated with equivalent strata of New York and the Cincinnati Arch.

Biodiversity, systematics, and new taxa of cladid crinoids from the Ordovician Brechin Lagerstätte

AbstractUpper Ordovician (Katian) strata of the Lake Simcoe region of Ontario record a spectacularly diverse and abundant echinoderm fauna known as the Brechin Lagerstätte. Despite recognition as the most taxonomically diverse Katian crinoid paleocommunity, the Brechin Lagerstätte has received relatively little taxonomic study since Frank Springer published his classic monograph on the “Kirkfield fauna” in 1911.Using a new collection of exceptionally preserved material, we evaluate all dicyclic inadunate crinoids occurring in the Brechin Lagerstätte, which is predominantly comprised of cladids (Eucladida and Flexibilia). We document 15 species across 11 genera, including descriptions of two new genera and four new species. New taxa include Konieckicrinus brechinensis n. gen. n. sp., K. josephi n. gen. n. sp., Simcoecrinus mahalaki n. gen. n. sp., and Dendrocrinus simcoensis n. sp.Although cladids are not commonly considered major components of the Early Paleozoic Crinoid Macroevolutionary Fauna, which is traditionally conceived as dominated by disparids and diplobathrid camerates, they are the most diverse major lineage of crinoids occurring in the Brechin Lagerstätte. This unexpected result highlights the important roles of specimen-based taxonomy and systematic revisions in the study of large-scale diversity patterns.UUID: http://zoobank.org/09dda7c2-f2c5-4411-93be-3587ab1652ab

Echinoderms of the Kuril-Kamchatka Trench

Echinoderms collected in the Kuril-Kamchatka Trench (KKT) at depths greater than 6000 m by expeditions onboard RV Vityaz and Sonne (KuramBio II) are listed, with some taxonomic and biogeographic remarks. The echinoderm fauna of the KKT (>6000 m) includes 44 species, of which 29 were determined to the species level and 15 to the generic level; 14 species and 6 genera (Echinosigra, Gephyrothuria, Mesothuria, Molpadia, Molpadiodemas and Sonnetrochus) were recorded for the KKT for the first time. The KKT echinoderm fauna mainly comprises species (86%) from the cosmopolitan genera. Of the 29 identified species, 11 (38%) are endemics of the hadal zone, including 6 (21%) endemics of the KKT. Species of holothurians make up more than half of all known echinoderm species in the KKT. The number of echinoderm species at depths 6000–7000 m is 29, which decreases sharply to 16 at depths 7001–8000 m, stabilizes at 17 at depths 8001–9000 m and further declines to 8 from 9001 to 10,000 m. The proportion of holothurians increases with depth from 48% to 87%. The number of species in the KKT echinoderm fauna is much greater than in any other trench. The second–highest echinoderm species richness (19 species) is known from the South Sandwich Trench. Both trenches are located in areas of high primary productivity and are characterized by a high abundance of benthic invertebrates in trawl catches.

The Echinoderm Fauna of the Azores (NE Atlantic Ocean).

In more than 150 years of research in the waters surrounding the Azores, several publications on the fauna of echinoderms of the archipelago have been produced, in the form of papers, notes, reports, reviews, and monographs. This work attempts to summarize the present knowledge on this marine group in the Azorean exclusive economic zone (i.e., waters within 200 nautical miles of the archipelago's shores). A short review of the history of the species' taxonomy is given, with key references, geographical distribution, ecology, additional notes and, when possible, figures. We herein report 172 species of echinoderms (6 crinoids, 55 ophiuroids, 45 asteroids, 36 holothurians, and 30 echinoids) from the Azores Archipelago, most of them inhabiting deep waters (>200 m). Only 29 shallow-water species were recorded locally (≤50 m depth). In general, the echinoderm species present in the Azores are characterized by a wide geographical distribution in the Atlantic Ocean. Only nine taxa (all deep-water species, >840 m) appear to be restricted to the Azorean waters. Overall, the knowledge of the echinoderm fauna of the Azores is out-dated, with many species last collected in the archipelago over 100 years ago. A recent interest in the Azorean Mid-Atlantic waters has brought oceanographic cruises back to the archipelago, thus providing new opportunities for the renewal of 150 years of echinoderm studies in the area.

Unexplored diversity of the mesophotic echinoderm fauna of the Easter Island ecoregion

The Easter Island ecoregion (EIE) is one of the most remote marine areas of the world and encompasses a vast and fragile ecosystem including oceanic islands and seamounts. In January 2014 and March 2016, a remotely operated vehicle was used to explore a subsurface peak off Easter Island (27.23°S, 109.48°W) and a seamount (26.92°S, 110.26°W), respectively located 10 km southwest and 98 km west of the island. More than 950 echinoderms were observed in the 5 h of video recorded during the seven dives conducted at depths between ~ 160 and 280 m. The communities of echinoderms observed at these depths markedly differed from those reported for shallower waters near Easter Island. Of the 20 morphospecies reported in the present study, only 5 were previously reported in the EIE. One species, six genera, and three families were reported for the first time in this area, and two new genera were discovered and described. A preliminary biogeographic analysis suggests affinities between the observed echinoderms and those of the West Pacific. These findings highlight the uniqueness of these assemblages and, therefore, the importance of considering them in the establishment of effective management strategies for these communities, which are within the Rapa Nui marine-protected area created in 2017.

Notes on Mississippian echinoderms from Hurdlow, Derbyshire, central England

The fossil echinoderms of the Lower Carboniferous (Mississippian) of Derbyshire remain understudied, principally due to the nature of the preservation rather than any lack of biodiversity. Echinoids and crinoids are described in float blocks of limestone from near Hurdlow, Derbyshire, which have been etched naturally after many years of being washed by weakly acidic rain. Surface detail is variable, commonly poor, but rare specimens retain enough features for tentative identification. Two species of echinoids are identified from rare disarticulated plates, namely Melonechinus? sp. (ambulacral plates) and archaeocidarid sp. (interambulacral plate); more and superior material will be necessary to confirm this division. Crinoids include a cladid brachial ossicle sp. with a distinctive sculpture; a columnal of a monobathrid camerate platycrinitid sp.; Annulocolumnus (col.) sp. cf. A. annulus Donovan, a columnal morphotaxon with an unusually broad axial canal; and Cyclocyclicus (col.) spp. This is the tenth echinoid site to be recognized from the Mississippian of the White Peak. Examination of etched float blocks provides a further method of investigation of the echinoderm fauna of this and other limestone areas.

Difficulties in the Identification of Deep Sea Ophiuroidea Post-Larvae from Makassar Strait, Indonesia and Their Implication for Taxonomic Studies

Brittle stars (Ophiuroidea) are one of the most difficult groups to be classified among five classes of echinoderm fauna. This is due to the limited information on their growth and development. Most of information on morphological description and ecology of the identified species were derived from the adult shallow water brittle stars. Meanwhile, the deep sea brittle stars, particularly larval and postlarval stages are less documented due to lack of investigation. This study investigated morphological characteristics of brittle star postlarvae collected from the deep sea of Makassar Strait on 8–15 June 2013. Six individual postlarvae of brittle stars were recorded. The important morphological characteristics of these postlarvae were described as preliminary record for similar future studies. All postlarvae collected in this study demonstrated lack of important structures for identification. Therefore, genetic studies may need to be carried out to identify the samples up to species level.

A new species ofHyattechinus(Echinoidea) from the type Devonian of the United Kingdom and implications for the distribution of Devonian proterocidarid echinoids

AbstractMany of the most diverse clades of Late Palaeozoic echinoids (sea urchins) originated in the Devonian period. Our understanding of diversity dynamics of these Late Palaeozoic clades are thus informed by new systematic descriptions of some of their earliest members. The Proterocidaridae are a diverse and morphologically distinct clade of stem group echinoids with flattened tests and enlarged adoral pore pairs, which are first known from the Upper Devonian. We herein report on a new species ofHyattechinus,Hyattechinus anglicusn. sp., from the Upper Devonian of the North Devon Basin, Devon, UK. This is the first DevonianHyattechinusknown from outside of the Appalachian Basin, USA, and provides novel information regarding the palaeogeographic and stratigraphic distribution of proterocidarids in Late Devonian times. We additionally update the stratigraphic distribution of DevonianHyattechinusfrom the Appalachian Basin, following recent biostratigraphic resolution of their occurrences.Hyattechinusappears to have been present in the Rheic echinoderm fauna during Late Devonian times, and comparison of the palaeoenvironmental setting ofHyattechinus anglicuswith that of otherHyattechinusfrom the Famennian of the Appalachian Basin suggests that the genus may have preferred siliciclastic settings. Furthermore, this new taxon increases the diversity of echinoids from the Upper Devonian of Devon to three species.

Checklist of the echinoderm fauna of the Adriatic Sea.

This paper presents a checklist of echinoderm species in the Adriatic Sea. The checklist is based on the review of the available literature data, with temporal coverage from the end of the 18th century to the present day, including the most recent investigations of benthic communities. A total of 108 species have been recorded: 2 species from class Crinoidea, 23 species from class Asteroidea, 22 species from class Ophiuroidea, 22 species from class Echinoidea and 39 species from class Holothuroidea. Non-indigenous echinoderm species have not been observed.