Cordatum Research Articles

Damage assessment on the discarded macro-benthic fauna in the Italian striped venus clam (Chamelea gallina) fisheries

The striped venus clam fishery in Italy is carried out by means of hydraulic dredges and it is one of the most important socio- economic activities in the Italian fisheries sector. Dredging has traditionally been considered among fishing activities with the greatest impact at the ecosystem level. Here, therefore, we investigated the disturbance level exerted by dredging on the studied area. Also, damage and mortality rates exerted by dredging on the discarded macro-benthic fauna living associated with Chamelea gallina during the summer season were investigated using a four-level damage scale, given three different haul time duration (3, 6 and 9 minutes). Despite the fact that macro-benthic fauna represented on average only 4.4% of the total catch, the most represented taxa in terms of both abundance and number were Malacostraca, Bivalvia, and Echinoidea. The analysis of the macro-benthic communities’ structure between hauls revealed that the species composition was very similar, and ABC plots together with the Warwick Statistics (W) revealed a moderately disturbed macro-benthic community. No significant difference was found in damage and mortality rates between hauls duration when stratified at taxon or species level. Overall, 61.0% of individuals of the catch were undamaged, whereas 16.1%, 3.7%, and 19.2% displayed slight, intermediate, and severe damage, respectively. We found that soft-shelled or soft-bodied species were the most affected by the harvesting process, whereas thick-shelled or thick-bodied species suffered the slightest damage. In particular, the species suffering major (severe) damage were the sea urchin Echinocardium cordatum (84.6%), the bivalves Mactra stultorum and Polititapes aureus (32.5% and 20.0%, respectively), the crab Liocarcinus vernalis (4.0%), and the sea star Astropecten irregularis (4.8%). The overall mortality rate of all discarded individuals was 22.9%, with E. cordatum showing the highest mortality rate of 96.0%. These findings highlight the importance of guaranteeing the integrity of the entire ecosystem through the adoption of suitable management plans and actions.

Effects of sediment disturbance by the heart urchin <i>Echinocardium cordatum</i> on the sediment–seawater solute exchange: An exclusion experiment

<p>Spatangoid heart urchins are dominant bioturbators in marine soft-sediment ecosystems worldwide. Their repeated sediment reworking prevents biogeochemical sediment stratification and colonization by other species, with implications for sedimentary reaction processes that affect the local sediment–seawater solute exchange. Here, we used a simple exclusion experiment to investigate how a subtidal <italic>Echinocardium cordatum</italic> population (18.2 ± 6.7 individuals m<sup>−2</sup>), foraging at an individual speed of ~45 cm per day affects the sediment–seawater solute exchange. To do so, we removed all heart urchins from eight one-meter-diameter areas of the 10-m deep seafloor of Man O'War Bay, Hauraki Gulf, New Zealand, and prevented recolonization and thus sediment reworking for 56 days. Subsequently, we measured the sediment–seawater exchange of O<sub>2</sub>, NO<sub>3</sub><sup>–</sup>, NO<sub>2</sub><sup>–</sup>, NH<sub>4</sub><sup>+</sup>, and N<sub>2</sub> both within and outside the exclusion areas, under light or dark conditions, and found no difference. The absence of a legacy effect of foraging <italic>E. cordatum</italic> after their removal suggests that, at least in this habitat, their influence on the sediment–seawater solute exchange may be limited to sediment being displaced in the immediate surrounding of the urchin. This unexpected result underlines the importance of evaluating the influence of bioturbators on the sediment–seawater solute exchange in the context of local environmental conditions, animal behavior, and population characteristics.</p>

Communities of macrozoobenthos on soft sediments in the coastal areas of open parts of Peter the Great Bay, Japan Sea and their ecological status

At least 10 communities of macrozoobenthos are determined by modern statistical methods on soft sediments in the coastal areas of Peter the Great Bay with the depth of ≥ 5 m surveyed in 1992, 1993 and 1996. They were: I. Scoletoma spp. + Ophiura sarsii; II. Aphelochaeta pacifica (I–II — in the Strelok Bay and Rifovaya Inlet); III. O. sarsii + Amphiodia fissa; IV. Scoletoma spp. + Mactra chinensis; V. Scoletoma spp. + Maldane sarsi; VI. Acila insignis (III–VI — in the Posyet Bay and adjacent area); VII. Scoletoma spp. + Echinocardium cordatum; VIII. Dipolydora cardalia + M. sarsi + O. sarsii; IX. Spiophanes uschakovi + E. cordatum, and X. Ampelisca macrocephala (VII–X — in the area at the Tumannaya/Tumen River mouth). Their development was determined by such environmental imperatives as the bottom sediments properties (silting degree, mean grain size), depth, and level of pollution and eutrophication. Majority of these communities (I, III, IV, V, VII, VIII, IX, and X) were in good ecological condition. Their habitats were slightly disturbed (intact or almost intact) and rare or never polluted and eutrophicated. The community II occupied more disturbed habitats with moderate ecological status reflected in higher indices of pollution. This community was rather likely formed in the process of succession in conditions of decreasing pollution. The community VI had a lower ecological status; its differentiation was probably caused by specific oceanographic regime of the Posyet Bay and anthropogenic impacts.

Characterization and differentiation of sublittoral sandbanks in the southeastern North Sea

Marine sublittoral sandbanks are essential offshore feeding grounds for larger crustaceans, fish and seabirds. In the southern North Sea, sandbanks are characterized by considerable natural sediment dynamics and are subject to chronic bottom trawling. However, except for the Dogger Bank, sandbanks in the southeastern North Sea have been only poorly investigated until now. We used an extensive, multi-annual dataset covering ongoing national monitoring programmes, environmental impact assessments, and basic research studies to analyse benthic communities on sublittoral sandbanks, evaluating their ecological value against the backdrop of similar seafloor habitats in this region. The analysis revealed complex spatial structuring of sandy seafloor habitats of the southeastern North Sea. Different infauna clusters were identified and could be specified by their composition of characteristic species. The sandbanks shared common structural features in their infauna community composition although they were not necessarily characterized by particularly high biodiversity compared to other sandy habitats. A close association of one of the main bioturbators in the southern North Sea, the sea urchin Echinocardium cordatum, with sandbanks was detected, which may promote the sediment-bound biogeochemical activity in this particular seafloor habitat. This would corroborate the status of sandbanks as sites of high ecological value calling for consideration in marine conservation.

Response of macrofaunal assemblages to different pollution pressures of two types of ports

Pollution status and benthic ecological quality of the two types of ports were assessed based on heavy metals and macrofaunal assemblages. Macrofaunal abundance and biomass in the industrial port were significantly higher than those in the fishing port. The dominant species of the two ports were Echinocardium cordatum and Nephtys oligobranchia. The AZTI marine biotic index (AMBI), multivariate AMBI, and Shannon-Wiener diversity index demonstrated that the benthic ecological quality of the two ports was moderate to good. The benthic ecological quality of the distant port sites was better than those of the nearby port sites. The geoaccumulation index and the Hakanson potential ecological risk index indicated that mercury posed a serious threat to port sediment pollution. AMBI, multivariate AMBI, and Shannon-Wiener diversity index were not good indicators for heavy metal pollution. The dominant species and Pielou’s evenness index were significantly correlated with heavy metal pollution and were good biological indicators.

Handling, Reproducing and Cryopreserving Five European Sea Urchins (Echinodermata, Klein, 1778) for Biodiversity Conservation Purposes.

In this work, five local sea urchin species found in European waters were studied. Four were regular species: Sphaerechinus granularis, Psammechinus miliaris, Echinus esculentus (Linnaeus, 1758) and the edible sea urchin Paracentrotus lividus; and one was an irregular species, Echinocardium cordatum. These five species of sea urchins have been studied regarding their fertility, toxicity of cryoprotecting agents, cryopreservation of different cell types and chilling injury. The baseline fertility is similar in P. lividus, P. miliaris and S. granularis. Nonetheless, the sperm:egg ratio, contact time and development of the fertilization envelope would need to be studied further on a case-by-case basis. Sperm can be maintained inactively in the gonad (4 °C), and oocytes also maintain quality in sea water (4 °C), even after 72 h. Sperm was cryopreserved for four species with some post-thaw intra specific variability, and embryo cryopreservation was only possible for S. granularis. Overall, this study provided a wider vision of the biology and reproduction of these species that will help us develop tools for their biodiversity conservation through cryopreservation.

Benthic ecosystem functioning under climate change: modelling the bioturbation potential for benthic key species in the southern North Sea.

Climate change affects the marine environment on many levels with profound consequences for numerous biological, chemical, and physical processes. Benthic bioturbation is one of the most relevant and significant processes for benthic-pelagic coupling and biogeochemical fluxes in marine sediments, such as the uptake, transport, and remineralisation of organic carbon. However, only little is known about how climate change affects the distribution and intensity of benthic bioturbation of a shallow temperate shelf sea system such as the southern North Sea. In this study, we modelled and projected changes in bioturbation potential (BPp) under a continuous global warming scenario for seven southern North Sea key bioturbators: Abra alba, Amphiura filiformis, Callianassa subterranea, Echinocardium cordatum, Goniada maculata, Nephtys hombergii, and Nucula nitidosa. Spatial changes in species bioturbation intensity are simulated for the years 2050 and 2099 based on one species distribution model per species driven by bottom temperature and salinity changes using the IPCC SRES scenario A1B. Local mean bottom temperature was projected to increase between 0.15 and 5.4 °C, while mean bottom salinity was projected to moderately decrease by 1.7. Our results show that the considered benthic species are strongly influenced by the temperature increase. Although the total BP remained rather constant in the southern North Sea, the BPp for four out of seven species was projected to increase, mainly due to a simultaneous northward range expansion, while the BPp in the core area of the southern North Sea declined for the same species. Bioturbation of the most important species, Amphiura filiformis and Echinocardium cordatum, showed no substantial change in the spatial distribution, but over time. The BPp of E. cordatum remained almost constant until 2099, while the BPp of A. filiformis decreased by 41%. The northward expansion of some species and the decline of most species in the south led to a change of relative contribution to bioturbation in the southern North Sea. These results indicate that some of the selected key bioturbators in the southern North Sea might partly compensate the decrease in bioturbation by others. But especially in the depositional areas where bioturbation plays a specifically important role for ecosystem functioning, bioturbation potential declined until 2099, which might affect the biochemical cycling in sediments of some areas of the southern North Sea.

Sediment hardness and water temperature affect the burrowing of Echinocardium cordatum: Implications for mass mortality during the 2011 earthquake–liquefaction–tsunami disaster

The heart urchin Echinocardium cordatum is an important bioturbator in shallow marine environments throughout the world. Although hard sediment and low water temperature are known to decrease the burrowing ability of benthic invertebrates, the effect of these factors on E. cordatum, one of the most important bioturbators, has remained unknown. Here, we quantified the burrowing ability (i.e., burrowing time) of this species in an aquarium where sediment hardness and water temperature were artificially controlled. The aquarium experiment revealed that both sediment hardness and water temperature significantly affected the burrowing time of E. cordatum. No significant interactions were detected between the two factors. Under hard-sediment and low-temperature (10 °C) conditions, reburrowing times for E. cordatum were around 3.5 times longer than with soft sediment and high temperatures (20 °C). The burrowing time in the hardened sediment due to liquefaction at low temperatures was compared with the observed in-situ interval between the occurrence of an earthquake and the first arrival of a tsunami. The results provide useful insights into the mass mortality of the species that was observed on the Pacific coast after the 2011 Tohoku Earthquake and associated liquefaction and tsunami events on March 11, 2011. Rapid reburrowing would have been vital at the time to prevent individuals from being swept away by tsunami currents after being expelled from the seafloor sediments by the seabed liquefaction. However, our results indicated that E. cordatum would not have been able to easily reburrow into the seafloor sediment, thereby becoming vulnerable to tsunami currents. This would have resulted in the heart urchin's observed mass mortality and prolonged absence from the region after the disaster.

Does trace fossil size correspond with burrower population density? An example from the modern counterpart of the trace fossil Bichordites

The trace fossil Bichordites appears as an intrastratal burrow and occurs in shallow-marine deposits. Its modern counterpart is the burrow produced by the spatangoid echinoid Echinocardium cordatum, found in shallow-marine regions. The relationship between burrow size and tracemaker population density was studied in the modern, subtidal, sandy deposits of a ria coast in the northeastern Japan. Burrow size decreases with increasing population density in the modern counterpart, suggesting that trace fossil size in Bichordites can be used as a proxy to quantify tracemaker population density at the time of trace formation. However, the factors that control burrow size are unclear and warrant further investigation.

First indications for reduced mortality of non-target invertebrate benthic megafauna after pulse beam trawling

Abstract Two alternative stimulation techniques to reduce mortality in benthic megafauna were tested relative to standard tickler chain beam trawling: longitudinal electrodes (pulse trawl) and longitudinal chains. Longitudinal chains caused higher mortality than pulse trawling in 3 species. Standard trawling gave higher mortality in Echinocardium cordatum than pulse trawling. Between longitudinal chain and standard trawling were no significant differences. This trend in decreasing mortality from longitudinal, to standard and then pulse trawling was confirmed by a similar decline in: i) numbers of significant species mortalities per trawl type, ii) average mortalities, i.e. longitudinal chain caused 41% more mortality than standard trawling and pulse trawling 43% less, iii) pre- and post-trawling community dissimilarities. A significant majority of species showed higher mortalities after longitudinal than after standard trawling and, conversely, lower mortalities after pulse trawling. Trawls with longitudinal chains instead of cross tickler chains increase megafaunal impact. On the contrary, pulse trawling can reduce the impact, although average mortality remains substantial (25%) even in impoverished benthic test assemblages in the southern North Sea. Power, generally was low and reference areas, free of (pulse) trawling, and inhabited by more vulnerable taxa will facilitate higher powered studies on the impact of standard and alternative trawling techniques.

Cidaroids, clypeasteroids, and spatangoids: Procurement, culture, and basic methods.

This chapter describes practical methods and key points for using non-camarodont echinoids including cidaroids (Order Cidaroida), clypeasteroids (also known as sand dollars; Order Clypeasteroida), and spatangoids (also known as heart urchins; Order Spatangoida) as experimental subjects for biological studies. The content described here is based on six Japanese species of echinoids (Astriclypeus manni, Clypeaster japonicus, Echinocardium cordatum, Peronella japonica, Prionocidaris baculosa, and Scaphechinus mirabilis). Specific topics addressed in this chapter include the collection and maintenance of adults, embryonic culture, and experimental procedures for micromanipulations, whole mount in situ hybridization, and immunological experiments.

MACROZOOBENTHIC COMMUNITIES IN THE EASTERN PART OF THE EASTERN BOSPHORUS STRAIT (PETER THE GREAT BAY, JAPAN SEA)

In total, 146 species of macrozoobenthos belonged to 11 taxonomic groups are found in the surveyed area in the eastern part of the Eastern Bosphorus Strait. Polychaetes have the highest species number, followed by bivalves and amphipods with five times less number of species. Polychaetes and bivalves have the highest occurrence, too, gastropods and amphipods occur frequently, as well. Bivalves dominate by biomass, but polychaetes — by their abundance. Benthos of the Patrokl Bight at the northern coast is poor relatively to the southern part of the strait at Russky Island because of low species diversity of amphipods, gastropods and decapods. Four macrozoobenthic communities are defined with the following titular species: Acila insignis + Scalibregma inflatum, Ophiura sarsi + Scoloplos armiger, Ennucula tenuis + Nicolea sp., and Dipolydora cardalia + (Melinna elisabethae or Maldane sarsi). Besides, Echinocardium cordatum dominates at the single station in the internal Patrokl Bight and Protocallithaca adamsi dominates at the single station in the Zhitkov Inlet. Majority of these communities are quite diverse and abundant. All of them, except the last case, are undisturbed or slightly disturbed and possess in good or moderate ecological state. In the case of the Zhitkov Inlet, the impoverished community of P. adamsi is considerably disturbed due to anthropogenic impact. Differentiation between the majority of communities is noted along gradients of natural environmental factors, as depth and fractional composition of bottom sediments. All conclusions are statistically significant and based on the results of consequential use of the factor and cluster analysis, non-metric multidimensional scaling and constrained correspondence analysis with bootstrap and randomization procedures. There is noted that the bottom communities in this area are subjected to rather significant contamination that supposedly causes decreasing of their stability and they may change their species composition and abundance under additional negative impact.

Lasting Impact of a Tsunami Event on Sediment‐Organism Interactions in the Ocean

AbstractAlthough tsunami sedimentation is a short‐term phenomenon, it may control the long‐term benthic environment by altering seafloor surface characteristics such as topography and grain‐size composition. By analyzing sediment cores, we investigated the long‐term effect of the 2011 tsunami generated by the Tohoku Earthquake off the Pacific coast of Japan on sediment mixing (bioturbation) by an important ecosystem engineer, the heart urchin Echinocardium cordatum. Recent tsunami deposits allow accurate estimation of the depth of current bioturbation by E. cordatum, because there are no preexisting burrows in the sediments. The in situ hardness of the substrate decreased significantly with increasing abundance of E. cordatum, suggesting that echinoid bioturbation softens the seafloor sediment. Sediment‐core analysis revealed that this echinoid rarely burrows into the coarser‐grained (medium‐grained to coarse‐grained) sandy layer deposited by the 2011 tsunami; thus, the vertical grain‐size distribution resulting from tsunami sedimentation controls the depth of E. cordatum bioturbation. As sandy tsunami layers are preserved in the seafloor substrate, their restriction on bioturbation continues for an extended period. The results demonstrate that understanding the effects on seafloor processes of extreme natural events that occur on geological timescales, including tsunami events, is important in revealing continuing interactions between seafloor sediments and marine benthic invertebrates.

Using tsunami deposits to determine the maximum depth of benthic burrowing.

The maximum depth of sediment biomixing is directly related to the vertical extent of post-depositional environmental alteration in the sediment; consequently, it is important to determine the maximum burrowing depth. This study examined the maximum depth of bioturbation in a natural marine environment in Funakoshi Bay, northeastern Japan, using observations of bioturbation structures developed in an event layer (tsunami deposits of the 2011 Tohoku-Oki earthquake) and measurements of the radioactive cesium concentrations in this layer. The observations revealed that the depth of bioturbation (i.e., the thickness of the biomixing layer) ranged between 11 and 22 cm, and varied among the sampling sites. In contrast, the radioactive cesium concentrations showed that the processing of radioactive cesium in coastal environments may include other pathways in addition to bioturbation. The data also revealed the nature of the bioturbation by the heart urchin Echinocardium cordatum (Echinoidea: Loveniidae), which is one of the important ecosystem engineers in seafloor environments. The maximum burrowing depth of E. cordatum in Funakoshi Bay was 22 cm from the seafloor surface.

Who really matters: Influence of German Bight key bioturbators on biogeochemical cycling and sediment turnover

Loss of bioturbating key species from marine sediments has been shown to strongly reduce benthic biogeochemical cycling and ecosystem functioning. It is thus of paramount importance to identify key bioturbators and quantify their effect on biogeochemical processes. To do so trait based community and species bioturbation potential (BPc and BPi) was mapped for 423 North Sea stations in the German Bight. Mapping of BPc and BPi identified Amphiura filiformis, Echinocardium cordatum and Nucula nitidosa as major bioturbating species in the German Bight. The effects of these species on benthic nutrient flux (i.e., changing concentrations of silicate ∆[SiO2], ammonium ∆[NH4+], nitrate ∆[NO3−] and nitrite ∆[NO2−]) were quantified in laboratory experiments together with their bioturbation rate (Db) and bioirrigation activity. The experiments indicated that mapped species bioturbation potential (BPi) may be a poor tool for identifying key bioturbators while calculated experimental BPi (expBPi) was a good indicator for species impact on biogeochemical cycling. Out of the three investigated species only E. cordatum significantly influenced biogeochemical cycling, whereas the effect of A. filiformis remained inconclusive potentially because arm damage and regeneration may affect the bioturbation activity of many individuals. The bivalve N. nitidosa showed only little impact on biogeochemical cycling, although this species was found to be an active bioturbator. Accordingly, E. cordatum may be considered one of the most important contributors to biogeochemical cycling at the sediment-water interface in the German Bight.

Chemical composition of spines and tests of sea urchins

The skeleton of spines and tests of the species of sea urchins Strongylocentrotus intermedius, Mesocentrotus nudus, Scaphechinus mirabilis, and Echinocardium cordatum from the Sea of Japan is composed of a spongy stereom, consisting of calcite with a high content of magnesium. It was found that the tests and spines of the skeletons of sea urchins are composed of calcium–organic composite materials inlaid with other metals: Mg, Fe, Zn, and Rb. In the four species of sea urchins studied, the strength and other mechanical properties of the tests and spines differ and depend on the chemical composition and structural organization of their components. It was shown that the content of volatile substances correlates with their fragility or elasticity. It is revealed that the chemical composition of the tests of two species of the spherical sea urchins S. intermedius and M. nudus indicates significant differences between these two species of sea urchins.

Molecular Genetic Markers of Intra- and Interspecific Divergence within Starfish and Sea Urchins (Echinodermata).

A fragment of the mitochondrial COI gene from isolates of several echinoderm species was sequenced. The isolates were from three species of starfish from the Asteriidae family (Asterias amurensis and Aphelasterias japonica collected in the Sea of Japan and Asterias rubens collected in the White Sea) and from the sea urchin Echinocardium cordatum (family Loveniidae) collected in the Sea of Japan. Additionally, regions including internal transcribed spacers and 5.8S rRNA (ITS1 - 5.8S rDNA - ITS2) were sequenced for the three studied starfish species. Phylogenetic analysis of the obtained COI sequences together with earlier determined homologous COI sequences from Ast. forbesii, Ast. rubens, and Echinocardium laevigaster from the North Atlantic and E. cordatum from the Yellow and North Seas (GenBank) placed them into strictly conspecific clusters with high bootstrap support (99% in all cases). Only two exceptions- Ast. rubens DQ077915 sequence placed with the Ast. forbesii cluster and Aph. japonica DQ992560 sequence placed with the Ast. amurensis cluster- were likely results of species misidentification. The intraspecific polymorphism for the COI gene within the Asteriidae family varied within a range of 0.2-0.9% as estimated from the genetic distances. The corresponding intrageneric and intergeneric values were 10.4-12.1 and 21.8-29.8%, respectively. The interspecific divergence for the COI gene in the sea urchin of Echinocardium genus (family Loveniidae) was significantly higher (17.1-17.7%) than in the starfish, while intergeneric divergence (14.6-25.7%) was similar to that in asteroids. The interspecific genetic distances for the nuclear transcribed sequences (ITS1 - 5.8S rDNA - ITS2) within the Asteriidae family were lower (3.1-4.5%), and the intergeneric distances were significantly higher (32.8-35.0%), compared to the corresponding distances for the COI gene. These results suggest that the investigated molecular-genetic markers could be used for segregation and identification of echinoderm species.

Symbiotic Association of the Bivalve Tellimya fujitaniana (Galeommatoidea) with the Heart Urchin Echinocardium cordatum (Spatangoida) in the Northwestern Pacific.

The bivalve Tellimya fujitaniana ( Yokoyama, 1927 ) (Galeommatoidea, Heterodonta) was described based on a fossil shell. Until now, the biology of living animals has not been reported. In this study, we found T. fujitaniana in a commensal relationship with the heart urchin Echinocardium cordatum (Pennant, 1777) (Spatangoida, Echinoidea) on the intertidal mud flats of the Seto Inland Sea, Japan. We investigated the morphology, host associations, and reproductive biology of this bivalve species. The elongate-ovate shell is covered by a reddish-brown ferruginous deposit. The mantle is exposed anteriorly to form a temporal siphon, while posteriorly one pair of short tentacles is exposed. Small individuals (shell length, SL, ≤ 2.1 mm) were attached to the host's body surface; middle-sized individuals (SL 3.0-3.2 mm) were attached to or stayed close to larger T. fujitanianathat were living freely in the host burrow. Nearly all the large individuals (SL ≥ 4.8 mm) lived freely in the host burrow, behind the urchin. This suggests that the host utilization pattern of T. fujitanianachanges with development. Specimens with SL ≥ 4.8 mm had mature gonads, mostly occupied by ova, and some individuals were brooding eggs or veliger larvae in the gills. This species was previously assigned to Fronsella. However, the morphology and ecology of this bivalve are very similar to those of Tellimya ferruginosa (the type species of the genus Tellimya) in the northeastern Atlantic Ocean. Thus, we have reassigned this species to genus Tellimya. We also confirmed that T. fujitaniana and T. ferruginosa can be genetically distinguished using the mitochondrial COI gene.

Middle Pleistocene interglacial deposits near Herning, Jylland, Denmark

Marine interglacial deposits are fairly common and widespread in Denmark, but so far none have been reported from the Herning area in central Jylland. In 2014, the Geological Survey of Denmark and Greenland (GEUS) received samples at one metre intervals from a borehole at 55°59.3´N, 8°56.6´E (elevation 27.56 m above sea level), at Hesselvigvej 7 near Kibæk in central Jylland (Fig. 1). The succession consisted of Miocene and Quaternary deposits. The Quaternary part was dominated by glaciofluvial sand and a single till bed, but it also contained a marine clay unit (16–21 m depth, 6.5–11.5 m a.s.l.). This marine clay contained spines of the sea-urchin Echinocardium cordatum, a boreal species known from Eemian and Holocene deposits from Denmark, but unknown from interstadial deposits. A lacustrine unit between 26 and 33 m depth (5.5 m b.s.l. to 1.5 m a.s.l.) consisted of clay, calcareous-rich gyttja and diatomite. Because Quaternary marine deposits are unexpected in this part of Denmark, we report here on analyses of pollen from the lacustrine unit and foraminifera from the marine unit, and we compare these with some interglacial records from Jylland. 

Comparative ultrastructure of spermatozoa from two regular and two irregular New Zealand echinoids

Spermatozoa from four species of echinoids found in New Zealand had morphological characteristics typical of other echinoids, including a conical sperm head with an acrosome-capped nucleus, a midpiece, and a single long flagellum. The spermatozoa of Fellaster zelandiae, Echinocardium cordatum, Evechinus chloroticus, and Centrostephanus rodgersii also showed statistically significant differences in species-specific morphological characteristics. Evechinus chloroticus showed the most variable sperm morphology. The irregular urchins (F. zelandiae and E. cordatum) had short, wide sperm heads (head length:width ratios 2.93:1 & 2.97:1, respectively) with a long acrosome complex, while the regular urchins (E. chloroticus and C. rodgersii) had longer, narrower heads with a short acrosome complex (ratios 5.29:1 & 3.37:1). Spermatozoa of E. cordatum from the New Zealand population shared more characteristics with those of conspecifics from the Sea of Japan than those of conspecifics from the Baltic, reflecting the membership of the former two populations in a distinct Pacific clade. Volumetric calculations showed no evidence of phylogenetic grouping. Mitochondria of E. chloroticus spermatozoa were less than half the volume of those of C. rodgersii and E. cordatum, and those of F. zelandiae were intermediate in volume. These volume measurements will be useful in physiological studies of sperm performance and quality.