Feather stars (Echinodermata: Crinoidea) are known to host a diversified associated fauna. Surprisingly, very few accounts on the crinoid epiphytic communities from the coasts of the India are available. The present contribution reports for the first time the crinoid-associated scale worm Paradyte crinoidicola (Potts, 1910) from Gujarat coastline, India. The species has been so far recorded from the southern part of Indian subcontinent, the Lakshadweep Islands as its first record from Indian coastline. Further research and documentation of these species will contribute to enhance our understanding of the diverse associations and complex interactions within Indian marine ecosystems. This highlights the necessity for more thorough field surveys and ongoing monitoring, as the region remains surprisingly underexplored.

A specimen of Prionotus punctatus was caught in Bahía Engaño, Chubut Province, Patagonia, Argentina. This extends the known distribution by 900 km and a 5.5° further south from its previous southernmost record. This record increases the number of species of the genus Prionotus and the fish diversity of central Patagonia. The presence of P. punctatus along with other recent reports of fish of tropical and subtropical lineages in central Patagonia adds new evidence on the ongoing tropicalization of the Patagonian Sea.

Providing nursery habitats to a number of marine fish larvae that recruit after prolonged pelagic larval duration, has been identified as one of ecosystem services rendered by estuaries and protected inshore water bodies like mangroves, mudflats, swamps, and marshes. Larval fish congregation and survival are largely dependent on abiotic and biotic potential of such systems and many migrant marine fishes are adapted to them. However, occurrences of larval forms of tropical reef-associated vagrant species which are known for extensive range adaptations generate considerable academic interest. The present study provides the first report of ontogenic habitat utilization of yellow fin surgeon fish, Acanthurus xanthopterus Valenciennes 1835 in a tropical microtidal positive estuary, the Vembanad lake, South India. Surface plankton collections from the downstream part of the estuary revealed considerable proportions of acanthurid larvae in post monsoon (mean 354 ± 180 numbers/100 m3) and pre monsoon (mean 217 ± 120 numbers/100 m3) while they were absent in monsoon season. These acronurus larval forms were morphologically identified and sorted before being subjected for DNA barcoding. Mitochondrial DNA COI sequences developed from morphologically characterized acronurus larvae exhibited genetic congruency to sequence of A. xanthopterus which was evident from phylogram (bootstrap support of 100) and genetic distance data (intraspecific distance of 0%). The study indicates that Acronurus larvae of A. xanthopterus, after extensive cross-habitat dispersal, utilize the estuarine habitat to promote potential growth.

Fast glacier motion is facilitated by slip at the ice-bed interface. For slip over rigid beds, areas of ice-bed separation (cavities) can exert significant control on slip dynamics. Analytic models of these systems assume that cavities instantaneously adjust to changes in slip and effective pressure forcings, but recent studies indicate transient forcings violate this—and other—underlying assumptions. To assess these incongruities, we conducted novel experiments emulating hard-bedded slip with ice-bed separation under periodic effective pressure transients. We slid an ice-ring over a sinusoidal bed while varying the applied overburden stress to emulate subglacial effective pressure cycles observed in nature and continuously recorded mechanical and geometric system responses. We observed characteristic lags and nonlinearities in system responses that were sensitive to forcing periodicity and trajectory. This gave rise to hysteresis not predicted in analytic theory, which we ascribed to a combination of geometric, thermal and rheologic processes. This framework corroborates other studies of transient glacier slip and we used it to place new constraints on transient phenomena observed in the field. Despite these divergences, average system responses converged toward model predictions, suggesting that analytic theory remains applicable for modeling longer-term behaviors of transiently forced slip with ice-bed separation.

We present a 1000 km transect of phase-sensitive radar measurements of ice thickness, basal reflection strength, basal melting and ice-column deformation across the Ross Ice Shelf (RIS). Measurements were gathered at varying intervals in austral summer between 2015 and 2020, connecting the grounding line with the distant ice shelf front. We identified changing basal reflection strengths revealing a variety of basal conditions influenced by ice flow and by ice–ocean interaction at the ice base. Reflection strength is lower across the central RIS, while strong reflections in the near-front and near-grounding line regions correspond with higher basal melt rates, up to 0.47 ± 0.02 m a−1 in the north. Melting from atmospherically warmed surface water extends 150–170 km south of the RIS front. Melt rates up to 0.29 ± 0.03 m a−1 and 0.15 ± 0.03 m a−1 are observed near the grounding lines of the Whillans and Kamb Ice Stream, respectively. Although troublesome to compare directly, our surface-based observations generally agree with the basal melt pattern provided by satellite-based methods but provide a distinctly smoother pattern. Our work delivers a precise measurement of basal melt rates across the RIS, a rare insight that also provides an early 21st-century baseline.

Haliotis Linnaeus, 1758, a commercially important gastropod, is the only known genus in the family Haliotidae (Mollusca, Vetigastropoda, or abalone) worldwide. Its poor Cenozoic record and high intraspecific variability resulted in different interpretations of nomenclature, impeding a robust species-level taxonomy and biogeographic history. Among the best-studied forms, three subspecies of H. tuberculata Linnaeus, 1758 currently inhabit the temperate waters of the Mediterranean and the eastern Atlantic. New findings in the Pliocene of Tuscany (Italy) are presented here, and the taxonomy of the European record is revised. On the basis of a multivariate analysis of shell morphometrics for the first time applied to the study of fossil abalones, and consistent with the chronostratigraphic and geographic framework, H. plioetrusca n. sp. is introduced and H. volhynica Eichwald, 1829 and H. lamellosoides Sacco, 1897 are reinstated as valid species. Some recently described forms from the Pliocene of Spain are placed in synonymy with H. lamellosoides. Haliotis ovata Michelotti, 1847 is proposed as the ancestral taxon of modern H. tuberculata, via H. lamellosoides. This lineage diversified in the subtropical/warm temperate Pliocene Mediterranean, represented by H. lamellosoides, H. bertinii Forli et al., 2003 and H. plioetrusca. The progressive global cooling starting at around 3.0 Ma is associated with the appearance of H. tuberculata at temperate latitudes. H. plioetrusca is not known from younger strata, whereas H. bertinii survived into the Calabrian.

UUID: http://zoobank.org/7c2f2258-2574-4976-a2f5-804c54c86679

The family Dendrophylliidae comprises a genus of azooxanthellate corals, Tubastraea (also known as ‘sun corals’ or ‘cup corals’), native from the Indo-Pacific and introduced into the Atlantic Ocean in the early 1940s. In Brazil, Tubastraea colonies were first registered on oil platforms on the northern coast of Rio de Janeiro state (22°S) in the late 1980s. Two decades later, these corals were for the first time identified in the Todos-os-Santos Bay (Bahia state, 13°S), a warmer environment with diverse marine ecosystems including estuaries, mangroves, and coral reefs. Intending to describe the biological cycle of exotic dendrophylliids from the Brazilian northeastern coast, histological analyses revealed three new reproductive structures for Scleractinia: (1) a mucin layer composed of acid glycoproteins surrounding immature sun coral oocytes, (2) trophonema or specialized cells connecting the oocyte to the adjacent gastrodermis, and (3) nucleolini, small condensations in nucleoli.

This study focuses on the synthesis of poly(3,4-dihydro-2H-pyran-alt-maleic anhydride) and poly(3,4-dihydro-2H-pyran-co-maleic anhydride-co-vinyl acetate) and their nanocomposites modified with organoammonium salts. The goal was to investigate the structural, dynamic mechanical and thermal properties of the polymers and nanocomposites, with a particular focus on the role of organoclay modification. In this study, bentonite was modified using alkyl ammonium salts with varying chain lengths (C14, C16 and C18). Ion-exchange processes led to the transformation of the character of bentonite from hydrophilic to hydrophobic, facilitating the formation of hybrid structures. Dynamic mechanical analysis, differential thermal analysis, differential scanning calorimetry and thermogravimetric analysis were used to characterize the viscoelastic and thermal properties of the polymers and their nanocomposites. The results showed that the incorporation of organoclay structures, particularly those modified with C18 alkyl groups, significantly improved the viscoelastic properties, with the greatest storage modulus being observed in the nanocomposites. The thermal analysis revealed that the nanocomposites exhibited a distinct three-step degradation process, unlike the copolymer, which underwent two-step degradation. Despite this difference, no significant improvement in thermal stability was observed in the nanocomposites compared to the copolymers. The study concludes that the incorporation of long-chain alkyl ammonium salts into bentonite and their use in copolymerization significantly impact the thermal and dynamic mechanical properties of the resulting nanocomposites. The modification of bentonite with C18 alkyl groups led to the most stable and dynamic mechanically robust nanocomposites, providing valuable insights into the role of organoclay modification in improving the performance of polymer-based nanocomposites.