Shallow-water Fauna Research Articles

Sympatric cryptic species in the crinoid genus Cenolia (Echinodermata: Crinoidea: Comasteridae) delineated by sequence and microsatellite markers

The marine species of the southern coast of Australia have not been well studied with regard to molecular connectivity. Cryptic species are expected to be prevalent on this coastline. Here, we investigate the crinoid genus Cenolia (Echinodermata: Crinoidea: Comasteridae) using molecular methods to elucidate cryptic species and phylogenetic relationships. The genus Cenolia dominates the southern Australian crinoid fauna in shallow waters. Few studies have examined crinoids for cryptic species at a molecular level and these have been predominantly based on mitochondrial data. We employ the nuclear markers 28S rRNA and ITS-2 in addition to the mitochondrial COI. Six divergent mitochondrial clades were identified. Gene flow between confirmed clades was subsequently examined by the use of six novel microsatellite markers, showing that sympatric taxa with low mtDNA divergences (1.7% K2P) were not interbreeding in the wild. The type specimens of Cenolia benhami and C. spanoschistum were examined, as well as all six divergent clades. Morphological characters dividing taxa were refined. Due to comb pinnule morphology, the New Zealand species benhami was determined to belong to the genus Oxycomanthus (nov. comb.). Three new species of Cenolia (including the Australian “benhami”) require description.

Late Viséan pelagic chondrichthyans from northern Europe

The relatively rich assemblages of shark teeth from pelagic limestone (Mississippian, late Visean, late Asbian—middle Brigantian) of three northern European regions: the Rhenish Mountains (Westenfeld Quarry, Germany), the Holy Cross Mountains (Todowa Grząba at the edge of Ostrowka Quarry, Poland), and Derbyshire (Cawdor Quarry, Matlock, England, UK) display certain similarities, with the absolute predominance of the teeth of Falcatidae (small Symmoriiformes) and the constant presence of Thrinacodus spp. The largest and most diverse assemblage from Todowa Grząba contains at least three species of a falcatid Denaea, a xenacanthimorph Bransonella nebraskensis, a newly described phoebodontid Thrinacodus dziki sp. nov., a few ctenacanthiform and euselachian teeth, and two abraded euchondrocephalan dental elements. Anachronistidae, common in the most of late Visean pelagic faunas, are absent from Todowa Grząba and Westenfeld. The material under study differs from the shallow-water chondrichthyan fauna, hitherto...

Biostratigraphy and Paleoecology of Maastrichtian Sediments in the Zagros Basin, Iran

Abstract:To enable the lithostratigraphic and biostratigraphic study of the Gurpi Formation, within the ‘Dezak’ or Globigerina Marl, a stratigraphic section at Booraki, located to the NNW of Shiraz, SW Iran, through the late Cretaceous was examined. The formation consists of shale and greenish‐gray marls interbedded with cream limestone, brown sandstones and siltstones with an exposed thickness of 160 m in the studied section. Samples were taken at regular intervals in all yielding 14 genera and 16 different species of benthic and planktic foraminifera that allowed determination of the age of the beds as Maastrichtian. To examine the paleoecology of the formation, some important ecological factors including water level, salinity, and oxygen regime change during the depositional courses of the formation were analyzed. The density of foraminiferans decreases from the base to top of the Gurpi Formation whereas the ratio of planktic to benthic Foraminifera (i.e., P/B) and proportion of shallow‐water fauna increase. These foraminiferal changes indicate an increase and decrease in depth, temperature, salinity and oxygen, respectively, at the base and top of the Formation.

Another inordinate fondness†: diversity of the tanaidacean fauna of Australia, with description of three new taxa

The shallow-water tanaidacean fauna of the Bass Strait has been the subject of recent intensive studies. The present paper extends this work into the deeper waters of the region, describing two new species and one new genus. The new species of the genus Paradoxapseudes has a combination of three maxillule palp setae, no plumose setae on the basis of pereopod 1 nor proximal serration on the antennal peduncle. The second species represents a new genus of the family Anarthruridae, having six marginal setae on the third maxilliped palp article and spines on the merus and carpus of the anterior pereopods. The high diversity of Tanaidacea in Australian waters is discussed. In particular, we conclude that Australian coasts suffer a diversity of immigration routes, have sufficient marine longevity, and afford such a diversity of available niches to have allowed multiple colonization and subsequent allopatric speciation of Tanaidacea. http://www.zoobank.org/urn:lsid:zoobank.org:pub:EE309A5A-E06D-416F-95BD-4C8D0D2BEB97

Phylogeography of the sand dollar genus Mellita: Cryptic speciation along the coasts of the Americas

Sand dollars of the genus Mellita are members of the sandy shallow-water fauna. The genus ranges in tropical and subtropical regions on the two coasts of the Americas. To reconstruct the phylogeography of the genus we sequenced parts of the mitochondrial cytochrome oxidase I and of 16S rRNA as well as part of the nuclear 28S rRNA gene from a total of 185 specimens of all ten described morphospecies from 31 localities. Our analyses revealed the presence of eleven species, including six cryptic species. Sequences of five morphospecies do not constitute monophyletic molecular units and thus probably represent ecophenotypic variants. The fossil-calibrated phylogeny showed that the ancestor of Mellita diverged into a Pacific lineage and an Atlantic+Pacific lineage close to the Miocene/Pliocene boundary. Atlantic M. tenuis, M. quinquiesperforata and two undescribed species of Mellita have non-overlapping distributions. Pacific Mellita consist of two highly divergent lineages that became established at different times, resulting in sympatric M. longifissa and M. notabilis. Judged by modern day ranges, not all divergence in this genus conforms to an allopatric speciation model. Only the separation of M. quinquiesperforata from M. notabilis is clearly due to vicariance as the result of the completion of the Isthmus of Panama. The molecular phylogeny calibrated on fossil evidence estimated this event as having occurred ∼3Ma, thus providing evidence that, contrary to a recent proposal, the central American Isthmus was not completed until this date.

Octocoral diversity and distribution on the south-west Indian coast

A survey of the distribution, percentage coverage, and diversity of octocoral fauna on the south-west coast of India yielded fourteen species from six families: Clavulariidae, Nephtheidae, Melithaeidae, Plexauridae, Gorgoniidae and Ellisellidae. This study produced ten new zoogeographical records of octocoral species to India, two species which were first records to the shallow water fauna (11–12 m depth), and one found to be a potential new record to the Indian coast. Octocoral coverage was <1% at all sites and diversity ranged from 6–13 species among the five study sites.

TAPHONOMIC AND PALEOECOLOGICAL ANALYSES (MOLLUSKS AND FISHES) OF THE SUA MEMBER CONDENSED SHELLBED, UPPER ONZOLE FORMATION (EARLY PLIOCENE, ECUADOR)

Abstract The early Pliocene sediments of the Sua Member (Onzole Formation) are spectacularly exposed along coastal cliffs in the surroundings of Sua (northwestern Ecuador). The shellbed at the base of these strata contains rich mollusk and fish assemblages and provides a rare opportunity to document the virtually unknown Pliocene shallow-water faunas of Ecuador. Stratigraphic context, faunal composition (both mollusks and fishes), biofabric trend, ichnological signatures, and taphonomic features presented here, all indicate that the shellbed is a stratigraphically condensed (hiatal) skeletal concentration generated primarily by low rates of net background sedimentation. Shellbeds of this type, immediately overlying a Glossifungites-demarcated ravinement surface, are regarded as onlap shellbeds and record landward stratal convergence and attenuation during the earliest phases of marine transgression. Although composed of largely autochthonous-parautochthonous specimens, the fossil assemblage contains mollu...

A high local species richness and biodiversity within high-latitude calcareous aggregates of tube-building polychaetes

In general, biodiversity and species richness follow the latitudinal diversity gradient and decrease from the tropics towards the poles. Exceptions have however been recorded, as for deep coldwater coral reefs at high latitudes, which comprise biodiversity hotspots. Here we assess and characterise the high-latitude (69°N) species richness and diversity of a local shallow-water fauna associated with small calcareous aggregations of a serpulid polychaete. A dense and very species rich fauna was recorded within aggregations of Filograna implexa Berkeley, 1828. Totally 4663 individuals belonging to 99 species (61 solitary, 38 colonial) were recorded in a total aggregation volume of only 4.4 l covering an area less than 0.05 m2 of a wreck situated in a tidal stream in North Norway. The number of species within each aggregation was positively related to its size, indicating that the high species diversity may be due to structural heterogeneity, which increase with aggregation size and probably creates new microhabitats and protect against predation. We present a species list including abundance and biomass, pin-point common species and describe a method for sampling such faunas associated with calcareous structures.

Phenotypic plasticity and taxonomy of Schloenbachia varians (J. Sowerby, 1817) (Cretaceous Ammonoidea)

Taxonomic concepts of Early–Middle Cenomanian representatives of Schloenbachia Neumayr, 1875 are evaluated based on well-preserved, abundant faunas from NE Iran (Atamir Formation, Koppeh Dagh) and Germany (Essen Greensand and Baddeckenstedt formations at several localities in northern Germany; Meisen Formation of Saxony). From a single Lower Cenomanian horizon in the Atamir Formation, a complete suite of specimens of Schloenbachia varians (J. Sowerby, 1817), ranging from moderately involute, compressed and finely ornamented (“forma subplana”) to more evolute, depressed and strongly spinose forms (“forma ventriosa”) with all transitional morphologies, is documented. Also in the shallow-water faunas of the “Klippenfazies” of the Essen Greensand Formation at Mulheim-Broich and of the Meisen Formation, all morphotypes co-occur. Thus, these forms cannot be regarded as geographic subspecies or successive chrono-subspecies, but reflect a high degree of variability in shell form and ornament (phenotypic plasticity) in S. varians. Interestingly, strongly tuberculate forms are rare to absent in contemporaneous offshore settings as documented by the Baddeckenstedt Formation. The phenotypic plasticity in Early Cenomanian S. varians populations is explained by ecophenotypic variation along a depth (proximal–distal) gradient: strongly tuberculate, depressed forms reflect comparatively shallow, nearshore environments with higher water energy and predation pressure, whereas compressed, weakly ornamented morphs are forms of open (and deeper) marine waters. The complete range of different forms is also observed in micro- and macroconchs, suggesting that the morphological variability is not controlled by sexual dimorphism. Based on its similarity to S. varians, also the Middle Cenomanian Ammonites coupei Brongniart, 1822 may be placed in the synonymy of the former.

Early Pleistocene Ostracods from the Hamada Formation in the Shimokita Peninsula, Northeastern Japan: the Palaeobiogeographic Significance of their Occurrence for the Shallow-Water Fauna

The early Pleistocene ostracod fauna from the Hamada Formation (ca. 1.5–1.2 Ma) was investigated in the Shimokita Peninsula, northeastern Japan. Twelve samples of this fossil fauna yielded 184 species, many of which are representative upper-shelf ostracods in the modern northeastern Japan Sea. Three biofacies were defined by Q-mode cluster analysis. The two most abundant species for each biofacies are Neonesidea sp. and Schizocythere kishinouyei in biofacies N, Buntonia hanaii and Yezocythere hayashii in biofacies B, and Laperousecythere robusta and Finmarchinella daishakaensis in biofacies L. The depositional environment of the individual biofacies can be defined as (1) upper-shelf area under open-sea influence in relatively high salinity (biofacies N), (2) inner—central-bay area, with relatively low salinity (biofacies B), and (3) bay-mouth area with intermediate salinity levels between those of (1) and (2) (biofacies L). Water depth decreased from the upper-shelf area through to the bay-mouth and then to the inner-central-bay areas during the depositional period of the studied horizons. The palaeoceanographic setting during most of the depositional period was estimated as the conditions of a water mass similar to the present Japan Sea Central Water, while surface waters were influenced by currents similar to the modern Tsugaru Warm and Oyashio Cold Currents. Based on the species content of biofacies B, Buntonia and Yezocythere commonly inhabited shallow inner-bay areas around 1.2 Ma in this region, instead of the modern representative inner-bay taxa of Japan which first appeared in the northernmost Honshu region after 1.0 Ma. The occurrence mode for extant and now-extinct species of the families Hemicytheridae, Cytheruridae and Eucytheridae suggests that the ostracod fauna in the upper-shelf environment from the Hamada Formation was similar to those from the southwestern to northeastern Japan Sea coast during the same period, even though it is situated at the easternmost extremity of the Japan Sea coastline (ca. 141°E) near the Pacific.

The onset of the Messinian salinity crisis: Insights from Cyprus sections

The Neogene basins of Southern Cyprus provide a good opportunity to improve the knowledge of the paleoenvironmental changes involved in the triggering of the Messinian evaporite deposition in the Mediterranean, and of their chronology, which is still questionable with regards to the parameters responsible for the triggering of the salinity crisis. It is still difficult to discriminate the individual effects of tectonics, climate, global sea-level changes. In Cyprus, considerable progress has been made on the events leading to the MSC, since the 70's, in high-resolution microfossil biostratigraphy, astrochronology, cyclostratigraphy and magnetostratigraphy. A study of the Tochni section, in the Psematismemos Basin, correlated with previously studied sections in the western Polemi and Pissouri basins, allows these regional paleoenvironmental changes to be correlated with the major events identified in other Mediterranean basins. The depth of the basins, in which evaporites were deposited, and the increase of salinity leading to the formation of evaporites are better constrained and studies confirm that restriction proceeded by steps throughout the Mediterranean. The very short time involved in the triggering of the onset of evaporite deposition in Cyprus basins is marked by tectonic instability, and development of very shallow water fauna and microbial communities indicating the water level lowered significantly just before the beginning of the massive gypsum precipitation. Correlation with other peri-Mediterranean basins, where similar changes have been observed, confirms that the period preceding the deposition of evaporites may correspond to the final closure of connections between the Atlantic Ocean and the Mediterranean Basin, leading to a sea-level drop and important hydrologic changes.

A new species of shallow-water sea pen (Octocorallia: Pennatulacea: Kophobelemnidae) from Antarctica

The pennatulacean genus Malacobelemnon has previously been considered to be distributed in the Western Indian and western Pacific Oceans, with one described species and another possible undescribed species from South Africa. An undescribed shallow-water species attributable to this Kophobelemnidae genus has been collected from the Antarctic region (King George, South Shetland Islands). The present paper reports this discovery, providing the description and illustrations of the new species, Malacobelemnon daytoni n. sp. Some of the characters previously considered in the genus Malacobelemnon should be slightly modified to include the new Antarctic species. The general colony shape, the distribution of siphonozooids, number of longitudinal autozooids rows, and the length and shape of the section of axis are the main characters used to distinguish the new species from the other in the genus M. stephensoni Tixier-Durivault 1965. From a bathymetric point of view, Malacobelemnon daytoni n. sp. is one of the shallowest pennatulacean species recorded, being an important contribution to the shallow-water Antarctic fauna.

Crustaceans of Mermaid (Rowley Shoals), Scott and Seringapatam Reefs, north Western Australia

– The atolls on the north-western Australian continental shelf are recognised in having a diverse shallow-water fauna with many widely distributed Indo-West Pacific species. However, the crustaceans of these reefs are poorly known.

Larger foraminifera as a substratum for encrusting bryozoans (Late Oligocene, Tethyan Seaway, Iran)

Considering the diversity and abundance of larger foraminifera examined from a wide range of Late Oligocene to Early Miocene palaeoenvironments in the Tethyan Seaway, encrusting bryozoans make extremely little use of their tests as substratum. Significant encrustations by bryozoans were exclusively found on large (o c. 6 cm), undulating tests of Lepidocyclina spp., on which, however, a remarkable 34 taxa of encrusting bryozoans were recorded. This shallow-water fauna of Chattian age was analyzed in respect of the bryozoan taxa present, colony growth type, and mode of budding, colony size, as well as onset of reproduction. Taxic and morphological similarities between the fossil assemblage and modern faunas encrusting mobile substrata indicate a long history of bryozoans as part of the interstitial habitat, while the tests of certain larger foraminifera may have played a significant role in the evolution of shallow-water bryozoans by providing substrata for encrusting species in otherwise unfavorable environments.

A route to recovery: The early Silurian shallow-water shelly fauna in the northern Oslo basin

The shelly fauna of the lowest part of the Saelabonn Formation in the Hadeland district of the Oslo Region provides a rare insight into the shallow-water biota of the earliest Silurian and hence the start of biotic recovery after the end Ordovician extinction event. It is dominated by the brachiopods Dalmanella cf. pectinoides Bergstrom, Coolinia cf. columbana (Reed), Leptaena cf. haverfordensis Bancroft and Zygospiraella scotica (Salter) together with the trilobite Acernaspis elliptifrons (Esmark). The first three species in this unique association belong to eurytopic Ordovician survivor genera which were also present in the underlying unit in Hadeland and continued to thrive during the Silurian. Significantly, Zygospiraella and Acernaspis have no unequivocal Ordovician record but diversified rapidly and became common during the early Silurian (Rhuddanian) in many parts of the world. Moreover, Acernaspis and Zygospiraella were highly eurytopic, pioneer taxa that were among the first elements of the Rhuddanian shelly fauna to appear in many parts of the world especially around the margins of the remnant Iapetus Ocean, following the drowning of areas previously emergent during the late Ordovician sea-level lowstand. The Hadeland fauna provides evidence of a previously undocumented route (among several) by which life ultimately returned to the global diversity plateau established in the mid-Ordovician.

Tanaidacea (Crustacea: Peracarida) from Japan. II. Tanaidomorpha from the East China Sea, the West Pacific Ocean and the Nansei Islands

The Japanese shallow water fauna of tanaidomorphan Tanaidacea are examined. Seven new species Tumidochelia knighti, Mesotanais birdi, Leptognathia bamberi, Typhlotanais magdalensis, Typhlotanais ohtsukae, Tanaella kommritzia and Chauliopleona hansknechti are described. Chauliopleona dentata Dojiri &amp; Sieg, 1997, from the type locality (California) is re-described. Leptognathia dentifera and L. unicinata are transferred to Tumidochelia. The genus Leptognathia is redefined and a number of species removed from the genus. The new leptognathid genera Biarticulata and Forcipatia are erected. A key to the Tumidochelia, Mesotanais, Leptognathia sensus stricto, and Forcipatia is given.

Tanaidacea (Crustacea: Peracarida) from Japan. I. Apseudomorpha from the East China Sea, Seto Inland Sea, and Nansei Islands

The Japanese shallow water fauna of Tanaidacea is examined. One new genus in the Parapseudidae Longipedis and two new species, L. fragilis and Hoplomachus toyoshious, are described. Androgynella nipponicus is herein re-erected. Apseudes nasutus is transferred to Longiflagrum.

Fossils, sediments, tectonics

Tectonic displacement and small-scale tsunamis apparently affected deposition of the Kolymbia limestone, Cape Vagia, Rhodes, Eastern Mediterranean. Coarse beds interrupt the sequential build-up of this Pliocene–Pleistocene bryomol limestone. Celleporid bryozoans, bivalves, and brachiopods dominate these beds. The palaeoecology of the thicket-forming Celleporaria palmata is re-evaluated and subsequently revised. The limestone comprises two parasequences in a transgressive systems tract, and deposition occurred at palaeodepths between 30 and 120 m. At intervals, tectonic movements lowered relative sea level and sent slumps of shallow-water fauna downslope. The depositional history was validated using independent sets of data: sediment structure and grain size, palaeobathymetry using bryozoan growth forms and occurrences of modern representatives of bryozoans and other taxa, basin configuration, and regional tectonics. Concordance of these lines of evidence provides a means of evaluating confidence in palaeoenvironmental inferences.

FORAMINIFERA IN AN ORGANIC-RICH, BRACKISH-WATER LAGOON, LAKE SAROMA, HOKKAIDO, JAPAN

We investigated the distribution of benthic foraminifera in Lake Saroma, a large lagoon on the coast of the Sea of Okhotsk in Hokkaido, Japan, to establish the characteristics of the foraminiferal fauna in these cool, organic-rich, brackish-water environments. Three types of faunas were identified: a Lagoon-bottom fauna dominated by Haynesina sp. A, a Shallow-water fauna dominated by Trochammina cf. japonica , and a River-mouth fauna dominated by Elphidium excavatum . The distribution of species is controlled by the dissolved oxygen content of bottom water in the summer, and a combination of organic enrichment and high mud content in the substrate that is specific to areas off river mouths. Haynesina sp. A opportunistically adapts to organic-rich and oxygen-poor conditions in deeper basins in the lagoon during the summer, whereas Trochammina cf. japonica mostly occurs in shallower areas where summer oxygen levels are high enough to sustain reproduction. Elphidium excavatum probably adapts to organic-rich sediments specific to areas near river mouths.

Species richness in macroalgae and macrofauna assemblages on Fucus serratus L. (Phaeophyceae) and Zostera marina L. (Angiospermae) in Skagerrak, Norway

The macrophytes Fucus serratus and Zostera marina form similar substrates for associated flora and fauna in shallow waters in Norway. While F. serratus forms a more or less continuous belt on rocky substrate along the coast, Z. marina forms disjunct populations on sandy or muddy bottoms. This study focused on the organisms associated with these two macrophytes in two localities in the Skagerrak region. In total, 130 taxa of epiphytic organisms were identified: 22 green algae, 41 red algae, 32 brown algae, eight diatoms and 27 sessile animals. One hundred and twenty-seven taxa of mobile macrofauna were registered. The dominant group was crustaceans, with amphipods as the order containing most species. Many species of both plants and animals preferred one or the other habitat. It is concluded that coastal macrophyte systems have high species diversity.