The first Cretaceous ophiopluteus skeleton (Echinodermata: Ophiuroidea)

2021 ◽  
pp. 1-9
Author(s):  
Mike Reich
Keyword(s):  
Fossil Record ◽  
Sea Urchins ◽  
Marine Ecosystems ◽  
Brittle Stars ◽  
Nw Poland

Abstract Larvae of sea urchins, brittle stars, and allies are common, ecologically important, and diverse members of marine ecosystems in all of the world's oceans today. In contrast to modern representatives, the fossil record of echinoderm larvae is poorly known. This study reports the first ophiopluteus skeleton from Cretaceous sediments worldwide, obtained from chalky sediment of the Isle of Wolin, NW Poland. The evidence presented here, that it is possible to isolate fossil echinoderm larval skeletons from rocks, indicates a hidden diversity of such fragile fossils and thus the possibility of direct geological recording.

scholarly journals Haplotype distribution and connectivity of the white sea urchin Tripneustes ventricosus across the Brazilian biogeographic province

2016 ◽  
Author(s):  
Wander O Godinho ◽  
Rodrigo Maggioni ◽  
Ana L Lacerda ◽  
Tito M C Lotufo
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Sea Urchin ◽  
White Sea ◽  
Sea Urchins ◽  
Marine Ecosystems ◽  
Brazilian Coast ◽  
The White Sea ◽  
Biogeographic Province ◽  
Fernando De Noronha

Sea urchins play important roles in marine ecosystems as key herbivores and some species have wide geographic range. The Atlantic white sea urchin Tripneustes ventricosus is abundant in many rock reefs of the eastern and western Atlantic, and may be found in high densities in Atolls and Archipelagos. Despite the importance of sea urchins in insular ecosystems, there is no study evaluating the genetic structure and the origin of the white sea urchin in isolated ecosystems. Such information is crucial to understand the connectivity and genetic diversity of these populations from the tropical Atlantic provinces. To evaluate the origin of the white sea urchin in Fernando de Noronha Archipelago and the genetic features of this population, we conducted studies on the population structure of the white sea urchin using mitochondrial DNA (COI), in two regions within the Brazilian biogeographic province and compared with other regions in the Atlantic. The white sea urchin from Fernando de Noronha was found to be genetically distinct, with FST ranging from 0.3 to 0.9 from other populations in Atlantic. The sharing of haplotypes between the Brazilian coast and the archipelago suggests that insular species derived from the Brazilian coast, rather than the East Atlantic. Moreover, all other Atlantic populations were genetically isolated, with low genetic diversity being a common characteristic among them (ranging from 0.0011 to 0.0022). The low connectivity found within populations might be related to the presence of soft barriers among the Brazilian biogeographic province. The low nucleotide diversity may also suggest that T. ventricosus may have undergone bottleneck processes at some stage of their evolution. This study has important implications on the geographic distribution, population structure and gene flow of the white sea urchin among the Atlantic regions. Further studies should evaluate the biological and ecological aspects of the species in both insular and continental marine ecosystems.

scholarly journals Biological and physical characterization of the seabed surrounding Ascension Island from 100–1000 m

2017 ◽  
Vol 97 (4) ◽  
pp. 647-659 ◽  
Author(s):  
E.T. Nolan ◽  
D.K.A. Barnes ◽  
J. Brown ◽  
K. Downes ◽  
P. Enderlein ◽  
...  
Keyword(s):  
Cold Water ◽  
Sea Urchins ◽  
Marine Ecosystems ◽  
Carbon Accumulation ◽  
Marine Biodiversity ◽  
Density Maximum ◽  
Camera System ◽  
Entire Area ◽  
Ascension Island ◽  
Underwater Camera

Recent studies have improved our understanding of nearshore marine ecosystems surrounding Ascension Island (central Atlantic Ocean), but little is known about Ascension's benthic environment beyond its shallow coastal waters. Here, we report the first detailed physical and biological examination of the seabed surrounding Ascension Island at 100–1000 m depth. Multibeam swath data were used to map fine scale bathymetry and derive seabed slope and rugosity indices for the entire area. Water temperature and salinity profiles were obtained from five Conductivity, Temperature, Depth (CTD) deployments, revealing a spatially consistent thermocline at 80 m depth. A camera lander (Shelf Underwater Camera System; SUCS) provided nearly 400 images from 21 sites (100 m transects) at depths of 110–1020 m, showing high variability in the structure of benthic habitats and biological communities. These surveys revealed a total of 95 faunal morphotypes (mean richness >14 per site), complemented by 213 voucher specimens constituting 60 morphotypes collected from seven targeted Agassiz trawl (AGT) deployments. While total faunal density (maximum >300 m−2 at 480 m depth) increased with rugosity, characteristic shifts in multivariate assemblage structure were driven by depth and substratum type. Shallow assemblages (~100 m) were dominated by black coral (Antipatharia sp.) on rocky substrata, cup corals (Caryophyllia sp.) and sea urchins (Cidaris sp.) were abundant on fine sediment at intermediate depths (250–500 m), and shrimps (Nematocarcinus spp.) were common at greater depths (>500 m). Other ubiquitous taxa included serpulid and sabellid polychaetes and brittle stars (Ophiocantha sp.). Cold-water corals (Lophelia cf. pertusa), indicative of Vulnerable Marine Ecosystems (VMEs) and representing substantial benthic carbon accumulation, occurred in particularly dense aggregations at <350 m but were encountered as deep as 1020 m. In addition to enhancing marine biodiversity records at this locality, this study provides critical baseline data to support the future management of Ascension's marine environment.

scholarly journals Brittle stars looking like starfish: the first fossil record of the Astrophiuridae and a remarkable case of convergent evolution

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8008
Author(s):  
Ben Thuy ◽  
Andy Gale ◽  
Lea Numberger-Thuy
Keyword(s):  
Fossil Record ◽  
Upper Cretaceous ◽  
New Genus ◽  
Parallel Evolution ◽  
Molecular Evidence ◽  
New Genus And Species ◽  
Brittle Stars ◽  
Remarkable Case ◽  
The Family ◽  
A New Species

The genus Astrophiura, which ranks among the most extraordinary of modern brittle stars, is the type genus of the recently resurrected family Astrophiuridae within the order Ophiurida. On account of its absurdly enlarged and strongly modified lateral arm plates, Astrophiura bears a closer resemblance to a pentagonal starfish than to a typical ophiuroid. Although molecular evidence suggests an ancient origin of the Astrophiuridae, dating back at least to the Early Jurassic, not a single fossil astrophiurid has been reported so far. Here, we describe dissociated lateral arm plates from the Campanian of Cringleford near Norwich, UK, and the Maastrichtian of Rügen, Germany (both Upper Cretaceous) with unambiguous astrophiurid affinities and assign these to a new species, Astrophiura markbeneckei. This represents the first fossil record of the family. In addition, the Rügen material included lateral arm plates that superficially resemble those of A. markbeneckei sp. nov. but differ in having spine articulations that are typical of the ophionereidoid family Amphilimnidae. We assign these plates to a new genus and species, Astrosombra rammsteinensis, an extinct amphilimnid with morphological modifications similar to those of Astrophiura, and thus representing a remarkable case of parallel evolution amongst brittle stars looking like starfish.

scholarly journals Distribution of macrozoobenthic taxa - potential indicators of vulnerable marine ecosystems in the western part of Bering Sea. 1. Anadyr Bay area

2017 ◽  
Vol 189 (2) ◽  
pp. 156-170
Author(s):  
Victor A. Nadtochy ◽  
Nickolay V. Kolpakov ◽  
Ilya A. Korneichuk
Keyword(s):  
Bering Sea ◽  
Feeding Habits ◽  
Marine Ecosystems ◽  
Bottom Trawl ◽  
Brittle Star ◽  
Similar Distribution ◽  
Brittle Stars ◽  
Sea Squirt ◽  
The Mean ◽  
Sea Squirts

Following recent tendencies in fisheries policy to ensure both sustainability of ecosystems and conservation of economically sustainable fisheries, protection of vulnerable resources with low direct economic value comes to the focus of fisheries management on ecosystem principles. One of the problems of modern fishing is a negative impact of bottom trawling because of destruction of benthic organisms vulnerable to mechanical impacts. This by-effect of fishing could affect negatively on functioning of bottom biocenoses, reproduction of exploited species, and decrease generally productivity of vulnerable marine ecosystems (VME). Potential VME indicators are determined for the area of the Anadyr Bay in the Bering Sea on the base of results of 4 benthic surveys using bottom sampler (1985, 2005) and bottom trawl (2008, 2012), as the most common species in some macrozoobenthic groups of epifauna. They are Gersemia rubiformis for soft corals, Myxilla incrustans , Halichondria panicea , Semisuberites cribrosa for sponges, Halocynthia aurantium , Boltenia ovifera for sea squirts, Cystisella saccata , Flustra foliacea for bryozoans, Chirona evermanni for barnacles, and Gorgonocephalus eucnemis for brittle stars. Their distribution is mapped. According to their life history and feeding habits, these species-indicators are divided onto two groups: immobile sestonophages (alcyonarians, sponges, ascidians, bryozoans, cirripedians) and mobile filtrators (brittle stars). The first group prevails on hard and mixed grounds mainly along southwestern and northeastern coasts of the Anadyr Bay at the depths of 80-90 m (sponges and bryozoans - to 250 m in the Navarin Canyon) with relatively warm water, active hydrodynamics and high biological productivity. The second group represented by G. eucnemis dominates on soft sediments in the central part of the Anadyr Bay with the depths of 50-270 m occupied by the cold water pool. Quantitative distribution of brittle star, on the one hand, and barnacles with sea squirts, on the other hand, is alternative to each other. On the contrary, barnacles, sponges and sea squirts have similar distribution of the biomass, being complementary species. Distribution patterns of all species-indicators are stable for many decades. However, biomass of some these species has changed in the southern Anadyr Bay between the similar surveys conducted in the 2008 and 2012: the mean biomass of barnacle Ch. evermanni and sea squirt H. aurantium had decreased in 6.5 and 3.7 times, respectively, whereas the mean biomass of sponges, brittle star G. eucnemis and sea squirt B. ovifera did not change. Bottom trawl fishery is not active in the northwestern Bering Sea, moreover, the habitats of immobile sestonophages with hard grounds are avoided by bottom trawlers being dangerous for fishing gears, so the observed decreasing of two species abundance is presumably caused by natural reasons or is a random error of the mosaic-distributed stocks assessment with insufficiently dense sampling grid.

Australian Echinoderms

2017 ◽  
Keyword(s):  
Sea Urchins ◽  
Abyssal Plain ◽  
Ecological Role ◽  
Sea Cucumbers ◽  
Brittle Stars ◽  
Comprehensive Information ◽  
Antarctic Waters ◽  
The Tropics ◽  
First Time ◽  
Feather Stars

Echinoderms, including feather stars, seastars, brittle stars, sea urchins and sea cucumbers, are some of the most beautiful and interesting animals in the sea. They play an important ecological role and several species of sea urchins and sea cucumbers form the basis of important fisheries. Over 1000 species live in Australian waters, from the shoreline to the depths of the abyssal plain and the tropics to Antarctic waters. Australian Echinoderms is an authoritative account of Australia’s 110 families of echinoderms. It brings together in a single volume comprehensive information on the identification, biology, evolution, ecology and management of these animals for the first time. Richly illustrated with beautiful photographs and written in an accessible style, Australian Echinoderms suits the needs of marine enthusiasts, academics and fisheries managers both in Australia and other geographical areas where echinoderms are studied. Winner of the 2018 Whitley Medal

scholarly journals Coordinated shifts to non-planktotrophic development in spatangoid echinoids during the Late Cretaceous

2009 ◽  
Vol 5 (5) ◽  
pp. 647-650 ◽  
Author(s):  
John A. Cunningham ◽  
Charlotte H. Jeffery Abt
Keyword(s):  
Larval Development ◽  
Late Cretaceous ◽  
Fossil Record ◽  
Evolutionary History ◽  
Sea Urchins ◽  
Geological History ◽  
Extrinsic Factors ◽  
Genus Level ◽  
History Of ◽  
Widespread Interest

Despite widespread interest in the interplay between evolutionary and developmental processes, we still know relatively little about the evolutionary history of larval development. Many clades exhibit multiple shifts from planktotrophic (feeding) to non-planktotrophic (non-feeding) larval development. An important question is whether these switches are scattered randomly through geological history or are concentrated in particular intervals of time. This issue is addressed using the Cretaceous spatangoid sea urchins, which are unusual in that larval strategy can be determined unambiguously from abundantly fossilized adult tests. Using a genus-level phylogeny, we identify five clades of non-planktotrophic taxa, each of which first appears in the fossil record in the Campanian or Maastrichtian (the final two Cretaceous stages). No examples of non-planktotrophy have been identified in any of the earlier stages of the Cretaceous. This strongly suggests that shifts to non-planktotrophic development are clustered in certain episodes of geological history, and this, in turn, implies that extrinsic factors operating at these times are responsible for driving shifts in developmental strategy.

scholarly journals Furongian (Jiangshanian) occurrences of radiodonts in Poland and South China and the fossil record of the Hurdiidae

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11800
Author(s):  
Xuejian Zhu ◽  
Rudy Lerosey-Aubril ◽  
Javier Ortega-Hernández
Keyword(s):  
South China ◽  
Fossil Record ◽  
Marine Ecosystems ◽  
Middle Cambrian ◽  
Early Devonian ◽  
Early Ordovician ◽  
Marine Life ◽  
Oral Cone ◽  
The Family ◽  
Sandstone Formation

The Furongian period represents an important gap in the fossil record of most groups of non-biomineralizing organisms, owing to a scarcity of Konservat-Lagerstätten of that age. The most significant of these deposits, the Jiangshanian strata of the Sandu Formation near Guole Township (Guangxi, South China), have yielded a moderately abundant, but taxonomically diverse soft-bodied fossil assemblage, which provides rare insights into the evolution of marine life at that time. In this contribution, we report the first discovery of a radiodont fossil from the Guole Konservat-Lagerstätte. The specimen is an incomplete frontal appendage of a possibly new representative of the family Hurdiidae. It is tentatively interpreted as composed of seven podomeres, six of which bearing laminiform endites. The best preserved of these endites is especially long, and it bears short auxiliary spines that greatly vary in size. This is the second occurrence of hurdiids and more generally radiodonts in the Furongian, the first being the external mould of an oral cone from Jiangshanian strata of the Wiśniówka Sandstone Formation in Poland. Restudy of this Polish specimen confirms that it belongs to a hurdiid radiodont and best compares to Peytoia. The family Hurdiidae includes the oldest (basal Cambrian Epoch 2) and youngest (Early Ordovician, possibly Early Devonian) representatives of the Radiodonta and as such, has the longest stratigraphical range of the group. Yet, hurdiids only became prominent components of marine ecosystems during the middle Cambrian (Miaolingian), and their fossil record in younger strata remains limited.

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