The coastal marine Tardigrada of the Americas

Abstract

The Western Hemisphere or the New World, also known as the Americas (North, Central and South America, associated islands and included seas) have historically been divided into two Realms, the Nearctic and Neotropical based on terrestrial biogeography. The coasts of these two terrestrial realms are bordered by six marine realms, 14 marine provinces and 67 marine ecoregions. From current literature, a comprehensive list of the marine tardigrade fauna from the Americas is presented. Data on marine tardigrades were obtained from 385 published Records of the Occurrence (RoO) of a species, their location, tidal zone, and the substrates from which they were reported. Authors' identifications were accepted at face value unless subsequently amended. Thirty genera and 82 species or subspecies are reported from the Americas; 49 species are documented from margins of the terrestrial Nearctic realm (North America) and 48 from terrestrial Neotropical realm (South America) with only 17 species occurring in both. We define cosmopolitan distribution for marine tardigrades as occurring in or on the margins of five of the seven oceans, only two species of marine tardigrade meets this standard. From the Americas 39 species have been described as new to science, 32 species appear restricted to the hemisphere. Taxa were assigned to marine ecoregions based on adjacent geopolitical units (country, states, provinces, etc.) described in published records. Although tardigrades have been reported from all six marine realms, they are only known from 21 of the 67 ecoregions. Most marine tardigrade sampling in the Americas has focused on near shore substrate (sand, mud, barnacles); for some species no substrates have been reported. The west coasts of both continents have little or no data about tardigrade presence.

Batillipes (Tardigrada, Arthrotardigrada) from the Portuguese coast with the description of two new species and a new dichotomous key for all species

“…This study also supports the need for more extensive and deeper surveys. Despite the interesting biological information that they can provide (de Zio grimaldi & gallo D'Addabbo 2001;Faurby et al 2011Faurby et al , 2012, biogeographical studies on marine tardigrades, and especially on Batillipes, are scarce, often restricted to generalist lists (e.g., Kaczmarek et al 2015;Miller & Perry 2016) and sometimes leading to contradictory interpretations. Actually, results of recent studies suggested that geographic / ecological factors can act as barriers, promoting speciation (e.g., Faurby et al 2011Faurby et al , 2012Zawierucha et al 2015;Faurby & Barber 2015) contrary to hypotheses in favour of wide-ranging species (e.g., hummon 1994).…”

Thalassic Rotifers from the United States: Descriptions of Two New Species and Notes on the Effect of Salinity and Ecosystem on Biodiversity

“…Two red eyespots ( Figure 4C), in dorsal view reniform to rounded, laterally at the base of the rostrum; each of them occasionally accompanied by a small roundish red eyespot. The number of nuclei in the vitellarium vary between 16 Redescription of the trophi by S.E.M. : ( Figure 5).…”