Identification and Distribution of Wedge Clams (Donacidae: Bivalvia) in Thailand by Geometric Morphometric and Molecular Analysis.

The phylogenetic relationship of living Thai Donacidae was herein studied. Two methodologies, geometric morphometrics (GM) and genetic analysis of COI sequences, were combined and applied to identify the valid taxa and explain biodiversity and the distribution pattern in this family. A total of 587 living specimens were tested to analyze the shape and size patterns by Elliptic Fourier Analysis (EFA). Shell identification and GenBank sequences were added to construct the phylogenetic relationship and haplotype network. Centroid size was used to identify the specimens to the subgenus level. Donax (Hecuba) scortum, was easily distinguished from other species by Principal Component analysis (PCA) of shell size and shape. Donax (Dentilatona) incarnatus and Donax (Deltachion) semisulcatus semisulcatus were identified using Canonical Variates Analysis (CVA). Pairwise comparison of EFA was used for species level recognition, particularly shape overlap was observed for medium and small shell size. Based on genetic distance and haplotype network of COI sequences, Donax (Latona) faba and D. (Latona) solidus could be grouped in the same clade. Intraspecific and interspecific genetic data variation of some common species in different geographical localities of Thailand was observed. Three distribution patterns of Donax species were observed along the two-marine system of Thailand.

Taxonomic Revision of Living Boring Bivalves Belonging to the Family Pholadidae Lamarck, 1809, (Bivalvia: Myida) from the Southwestern Atlantic.

Boring bivalves of the family Pholadidae Lamarck, 1809 living in Argentinean and Uruguayan waters are herein revised. The literature research revealed twelve nominal species of Pholadidae mentioned as living in the study area. Type material of all nominal taxa were examined when it was possible. Additional specimens from field works and malacological collections were studied, illustrated and re-described. Details of type localities, repositories, and distribution range are provided for each valid taxa. This work revealed the presence of five native and one introduced species belonging to Pholadidae in Argentinean and Uruguayan waters. Barnea (Anchomasa) lamellosa, Cyrtopleura (Scobinopholas) lanceolata, Pholas (Thovana) campechiensis and Martesia fragilis belonging to the Argentine biogeographical province; Netastoma darwinii from Magellan province; and Barnea (Anchomasa) truncata introduced in the Bahía Blanca estuary. Finally, morphological comparison with congeneric species distributed in American seas are provided.

Systematic redescription of Solen/ (Ensisolen/) tehuelchus/ and Ensis/ macha/ (Bivalvia: Solenoidea) from Argentina, southwestern Atlantic Ocean.

In the present study, bivalves belonging to the superfamily Solenoidea that inhabit the Argentinean Sea are redescribed. The specimens studied in this work were collected by scuba diving in the Gulf of San José, Argentina. Additional specimens from different malacological collections were revised to update the geographical distribution of valid species. According to the literature, there exist two species for the "Argentinean" and "Magellan" biogeographical provinces. However, ten nominal taxa, with uncertain taxonomic status, have been mentioned for the study area. Field work, local collection survey and type material examination allow confirming two valid species: Solen (Ensisolen) tehuelchus Hanley (Solenidae) and Ensis macha (Molina) (Pharidae). A morphological comparison between S. tehuelchus and S. gaudichaudi Chenu and S. obliqua Spengler is provided as well type locality, repository and synonymy list. The type material of all related species are illustrated whenever possible. Establishing the valid names of these species is the first step towards more integrative studies including genetic and zoogeographical analyses.

Marine invertebrate and seaweed biodiversity of continental coastal Ecuador.

This study summarises the diversity of living macroinvertebrates and seaweeds from the intertidal and subtidal rocky shores along Ecuadorian continental coast. Benthic macroinvertebrate communities and seaweeds were quantified over quadrants (50 × 50 cm) randomly placed on transects of 50 m length. A checklist of 612 species was generated: 479 species of macroinvertebrates and 133 species of seaweeds. Groups recorded were Mollusca (184 species), Cnidaria (70), Arthropoda (68), Annelida (60), Echinodermata (42), Chordata (18), Bryozoa (13), Porifera (22), Sipuncula (2), Brachiopoda and Platyhelminthes (only identified as morphotypes). The seaweeds were represented by Rhodophyta (78), Chlorophyta (37), Ochrophyta (13), Cyanobacteria (5) and 19 biotic complexes. Furthermore, 22 new taxa and six alien species were recorded from the intertidal zone. This study provides the first large scale report of benthic communities in different marine coastal ecosystems in mainland Ecuador, covering 1,478 km2 of protected areas and 382 km2 of non-protected areas. The highest benthic diversity was registered in the protected areas and rocky shores from the intertidal zone. The biological data, herein reported, are useful for a long-term monitoring programme to evaluate the status of conservation and to detect rapid changes in the benthic biodiversity from coastal areas.

Characterization of the Elastoplastic Response of Low Zn-Cu-Ti Alloy Sheets Using the CPB-06 Criterion.

Unlike other HCP metals such as titanium and magnesium, the behavior of zinc alloys has only been modeled in the literature. For the low Zn-Cu-Ti alloy sheet studied in this work, the anisotropy is clearly seen on the stress-strain curves and Lankford coefficients. These features impose a rigorous characterization and an adequate selection of the constitutive model to obtain an accurate representation of the material behavior in metal forming simulations. To describe the elastoplastic behavior of the alloy, this paper focuses on the material characterization through the application of the advanced Cazacu-Plunket-Barlat 2006 (CPB-06 for short) yield function combined with the well-known Hollomon hardening law. To this end, a two-stage methodology is proposed. Firstly, the material characterization is performed via tensile test measurements on sheet samples cut along the rolling, diagonal and transverse directions in order to fit the parameters involved in the associate CPB-06/Hollomon constitutive model. Secondly, these material parameters are assessed and validated in the simulation of the bulge test using different dies. The results obtained with the CPB-06/Hollomon model show a good agreement with the experimental data reported in the literature. Therefore, it is concluded that this model represents a consistent approach to estimate the behavior of Zn-Cu-Ti sheets under different forming conditions.

Marine invertebrate biodiversity from the Argentine Sea, South Western Atlantic.

The list of marine invertebrate biodiversity living in the southern tip of South America is compiled. In particular, the living invertebrate organisms, reported in the literature for the Argentine Sea, were checked and summarized covering more than 8,000 km of coastline and marine platform. After an exhaustive literature review, the available information of two centuries of scientific contributions is summarized. Thus, almost 3,100 valid species are currently recognized as living in the Argentine Sea. Part of this dataset was uploaded to the OBIS database, as a product of the Census of Marine Life-NaGISA project. A list of 3,064 valid species, grouped into 1,662 genera distributed in 808 families and 23 phyla, was assessed. The best represented taxa were Arthropoda and Mollusca, contributing approximately with the 50% of the mentioned species in the literature. Cumulative species curves were analyzed in order to estimate the percentage of marine invertebrate biodiversity that is currently known. However, no model fit to our data, showing that the recorded species represent less than 50% of the expected marine invertebrate biodiversity for the Argentine Sea. The great surface of the Argentine Marine Platform (6,581,500 km2) and the relative low effort in collecting and studying new species due to economical restrictions could explain the low fraction of described species. The training of new taxonomists, as well as, the support of projects that contribute to the knowledge of marine invertebrate biodiversity from South Western Atlantic is recommended.

Zulma Ageitos de Castellanos: Publications and status of described taxa.

Zulma Ageitos de Castellanos was an Argentinian malacologist working in the "Facultad de Ciencias Naturales y Museo" at La Plata University where she taught invertebrate zoology between 1947 and 1990. Her scientific publications are listed in chronological order. Described genus-group and species-group taxa are listed. Information about the type locality and type material, and taxonomic remarks are also provided. Finally, type material of all described taxa was requested and, when located, illustrated.