First Report of the Marine Benthic Dinoflagellate Bysmatrum subsalsum from Korean Tidal Pools

Dense patches were observed in the tidal pools of the southern area of Korea. To clarify the causative organisms, the cells were collected and their morphological features were examined using light and scanning electron microscopy (SEM). In addition, after establishing strains for the cells the molecular phylogeny was inferred with concatenated small subunit (SSU) and large subunit (LSU) rRNA sequences. The cells were characterized by a nucleus in the hypotheca, strong reticulations in thecal plates, the separation of plates 2a and 3a, the tear-shaped apical pore complex, an elongated rectangular 1a plate and the absence of the right sulcal list. The thecal plate formula was Po, X, 4′, 3a, 7″, 6c, 4S, 5′′′, 2′′′′. Based on these morphological features, the cells were identified as Bysmatrum subsalsum. In the culture, the spherical cysts of B. subsalsum without thecal plates were observed. Molecular phylogeny revealed two ribotypes of B. subsalsum are identified; The Korean isolates were nested within the ribotype B consisting of the isolates from China, Malaysia and the French Atlantic, whereas the ribotype A includes only the isolates from the Mediterranean Sea. In the phylogeny, B. subsalsum and B. austrafrum were grouped. This can be supported by the morphological similarity between the two species, indicating that the two species may be conspecific, however B. subsalsum may distinguish from B. austrafrum, because of differences in the types of eyespots reported in previous studies. These findings support the idea that there is cryptic diversity within B. subsalsum.

First record of Scrippsiella trochoidea (Dinophyceae) in Shatt Al-Arab River (Southern Iraq)

Even though very few biological data on dinoflagellates from Iraqi aquatic ecosystems are available to date, there are none on the genusScrippsiella. For this reason, the survey was conducted along four sites in the Shatt Al-Arab River between November 2009 and July 2010. A dense population ofScrippsiella-like dinoflagellate was observed in the studied samples during November and December 2009. Less dense population of the same taxon was encountered in the downstream sites in July 2010. Based on observations of thecal plate pattern in epifluorescence microscopy, the species was attributed toScrippsiella trochoidea. The occurrence ofS. trochoideais reported for the first time in Iraqi waters from a wide range of temperature (17.9°C–35.2°C) and salinity (2.3–16.7).

Cheirocystis fultonensis, a new glyptocystitoid rhombiferan from the Upper Ordovician of the Cincinnati Arch—comments on cheirocrinid ontogeny

A new glyptocystitidoid rhombiferan, Cheirocystis fultonensis, is described from the contact zone between the Point Pleasant Formation and lower Kope Formation exposed 50 km south east of Cincinnati, Ohio. This species, the second known glyptocystitidoid rhombiferan from the Cincinnatian Series and the youngest known species of Cheirocystis, shows significant suture modification where pectinirhombs are placed. Growth of large pectinirhombs along vertical sutures results in an unusual bowing-out of thecal plate sutures that is also seen in the related species Cheirocystis anatiformis. A juvenile specimen shows that ontogenetically the lateral shared ambulacra become less pronounced, pectinirhombs are added until the eight standard positions are expressed, and the periproct becomes proportionately smaller with age.

Morphological and paleoecological analysis of the Ordovician ankyroid Lagynocystis (Stylophora: Echinodermata)

Despite its atypical thecal plate pattern, Lagynocystis pyramidalis (Jaekel, 1918) (Middle Ordovician, Northern Gondwanaland) is composed of normally positioned marginal plates on the left side of the theca, whereas those on the right side are shortened or missing in comparison with marginal plates of other ankyroids. The only somatic on the lower thecal surface is the CS plate. The abnormally long distal aulacophore, reduced theca, and internal ctenoid organ are interpreted as adaptations to deep water, dysaerobic environmental conditions. Ctenoid organ morphology is re-evaluated and is interpreted to have both feeding and respiratory functions. Loss of plates relative to a presumed ancestor similar to Barrandeocarpus has resulted in torsion that places somatic platelets, originally on the superior face, onto the inferior face and in contact with both CS and M′3 plates.

New echinoderms from the Early Ordovician of west Texas

Four specimens of blastozoan and crinozoan echinoderms are described from the Lower Ordovician El Paso Group in the southern Franklin Mountains just north of El Paso, west Texas.Cuniculocystis flowerin. gen. and sp., based on two partial specimens, appears to be a typical rhombiferan in most of its morphologic features except that it lacks pectinirhombs and instead has covered epispires (otherwise known only from Middle Ordovician eocrinoids) opening on most of the thecal plate sutures. The covered epispires inCuniculocystisindicate that some early rhombiferans had alternate respiratory structures and had not yet standardized on pectinirhombs, a feature previously used as diagnostic for the class Rhombifera.Bockia?elpasoensisn. sp. is a new eocrinoid based on one poorly preserved specimen that has a small ellipsoidal theca and unbranched brachioles attached to a flat-topped spoutlike summit. It is the earliest known questionable representative of this genus and the only one that has been described from North America.Elpasocrinus radiatusn. gen. and sp. is an early cladid inadunate crinoid based on a single well-preserved calyx. It fits into a lineage of early cladids leading to the dendrocrinids and toCarabocrinus.Several additional separate plates, stem segments, and a holdfast of these and other echinoderms are also described.