A world dataset on the geographic distributions of Solenidae razor clams (Mollusca: Bivalvia)

Abstract Background Using this dataset, we examined the global geographical distributions of Solenidae species in relation to their endemicity, species richness and latitudinal ranges and then predicted their distributions under future climate change using species distribution modelling techniques (Saeedi et al. 2016a, Saeedi et al. 2016b). We found that the global latitudinal species richness in Solenidae is bi-modal, dipping at the equator most likely derived by high sea surface temperature (Saeedi et al. 2016b). We also found that most of the Solenidae species will shift their distribution ranges polewards due to global warming (Saeedi et al. 2016a). We also provided a comprehensive review of the taxon to test whether the latitudinal gradient in species richness was uni-modal with a peak in the tropics or northern hemisphere or asymmetric and bimodal as proposed previously (Chaudhary et al. 2016). New information This paper presents an integrated global geographic distribution dataset for 77 Solenidae taxa, including 3,034 geographic distribution records. This dataset was compiled after a careful data-collection and cleaning procedure over four years. Data were collected using field sampling, literature and from open-access databases. Then all the records went through quality control procedures such as validating the taxonomy of the species by examining and re-identifying the specimens in museum collections and using taxonomic and geographic data quality control tools in the World Register of Marine Species (WoRMS) and the r-OBIS package (Provoost and Bosch 2017). This dataset can thus be further used for taxonomical and biogeographical studies of Solenidae.


Introduction
Solenidae is an ecologically and economically important family of marine bivalves called razor clams (Cosel 1990, Saeedi et al. 2009, Saeedi et al. 2011, Saeedi et al. 2012. They comprise three genera, Solen Linnaeus, 1758 with 67 accepted species and Solena Mörch, 1853 with two accepted species, including S. obliqua and S. rudis and Neosolen (Ghosh, 1920), including species N. aquaedulcioris (Cosel 1989, Cosel 2002, Saeedi and Costello 2013, Saeedi et al. 2013, Bouchet 2014. These bivalves burrow down to about 30 cm in low intertidal and sub-tidal sandy -muddy sediments (Saeedi et al. 2009, Saeedi et al. 2013. They are suspension feeding bivalves with a free-swimming larva and adults can grow 20-30 mm per year in length (Saeedi et al. 2009). Solenidae are distributed worldwide in marine coastal and shelf ecosystems down to a depth of 100 m (Saeedi et al. 2013). The highest Solenidae species richness is in the Indo-Pacific and the family is absent from the polar regions and some oceanic islands such as New Zealand (Saeedi et al. 2013, Saeedi et al. 2016b).
Here, we publish a world dataset of Solenidae species distribution records that was compiled from our personal observations, literature, the Global Biodiversity Information Facility (GBIF) and the Ocean Biogeographic Information System (OBIS). A concern in using these data is that its fitness for use may be compromised by misapplication of species names, misspellings of names, occurrence of synonyms, errors in geo-referencing and mis-identification of specimens in museum collections (Costello et al. 2007, Robertson 2008, Saeedi and Costello 2013. Having an accurate and reliable geographic distribution dataset is necessary to study the global biodiversity and biogeography of the selected taxa.
The present data have been vetted and used in several publications on species biogeography.

General description
Purpose: Publishing a standardised geographic distribution dataset that can be further used to study the taxonomy, biogeography, latitudinal species richness patterns and model future distributions of Solenidae.

Study extent: Global
Sampling description: Data on Solenidae species' geographic distributions were obtained from the Global Biodiversity Information Facility (GBIF), Ocean Biogeographic Information System (OBIS), published literature, museum collections, personal correspondence and field sampling (). In addition, specimens of Solen dactylus were collected between 2006 to 2013 from Bandar Abbas in the south of Iran, northern Persian Gulf. Individuals were collected using a long steel wire with a V shape hook at one end) (Saeedi 2015). Specimens of Solen marginatus were collected using the salt method at A Pobra do Caraminal, A Coruna, Spain (42°36'47.6202" N, 8°55'38.5644" S) in February 2013 .

Quality control:
We cross-referenced OBIS and GBIF data to avoid duplication of records. We excluded all records that were classified as fossils, were mapped on land and where location precision was unknown or more than 100 km. Regarding geographic data quality control, we used a gazetteer (http://www.marineregions.org/gazetteer.php?p=search) and r-OBIS R-package created by OBIS to quality control the data.
We also manually examined and re-identified specimens at the Natural History Museum of Paris (France), Auckland Museum (New Zealand), the National Museum of Natural History (Smithsonian) in Washington D.C. (USA) and the Natural History Museum of London ( Fig.  1) and recorded where they had been collected.

Geographic coverage
Description: This study provides an integrated global geographic distribution dataset of all accepted Solenidae species.

Taxonomic coverage
Description: After the data-cleaning, a total of 3,034 Solen and Solena species records (Suppl. materials 1, 2, 3, 4) were collated and used to plot the global distributions of Solenidae species (Fig. 2). About 38% of distribution records (1,150 records) were extracted from GBIF and OBIS; about 58% of the records were collected from museum collections (1,733 records) and about 4% were sourced from literature and personal correspondence. Solen marginatus had the highest number of records, with about 20% of the total number of records of all Solenidae species. We found reliable coordinates for 67 of the 69 accepted Solen and Solena species, listed in WoRMS. We found another nine potential species described as aff. and cf. In total, 77 Solenidae taxa (we use the term 'taxa' as some species in Tables 1 and 2 were not identified to the species level) were used in this study (Suppl. material 1).

Figure 1.
Mis-identifications of five species in Auckland and Smithsonian museums. About 35 species (150 specimens) in different museums were re-identified. The top three species were reidentified in Smithsonian (correct identification labels as pink sticker). The last two images show that Solen fonesii and Solen marginatus (correct identification labels as yellow sticker) were mis-identified as Solen vagina.
Solenidae species are distributed worldwide from -60 to +60 degree in latitude and they are absent from the polar regions and some oceanic islands such as New Zealand. In total, the eastern Pacific has 10 endemic Solen species and one endemic Solena, S. rudis. The Atlantic Ocean has eight Solen species and one endemic Solena species, S. obliqua, which occurs along the tropical mid-west Atlantic coasts of the Caribbean Sea. Europe and the Mediterranean Sea have only one species, S. marginatus, which is endemic. The Indo-West Pacific and north-west Pacific has the highest number of Solenidae species (about 50). New Caledonia has two Solen species that are both endemic. maximumDepthInMeters Maximum depth reported for the record, in metres.

decimalLatitude
The geographic latitude (in decimal degrees, using the spatial reference system given in geodeticDatum) of the location where record was reported. decimalLongitude The geographic longitude (in decimal degrees, using the spatial reference system given in geodeticDatum) of the location where record was reported.
occurrenceID A unique identifier for the occurrence record specifically created for this dataset. scientificName The accepted scientific name of the record.
scientificNameAuthorship The accepted authorship of the scientific name.
scientificNameID LSID number recorded for the accepted scientific name of the record. kingdom The full scientific name of the kingdom in which the taxon is classified. taxonRank The lowest taxonomic level where the record is identified.