A trans-isthmus survey of marine tardigrades from Costa Rica (Central America) with descriptions of seven new species

ABSTRACT

The Central American Isthmus has had profound effects on the evolution and distribution of larger marine organisms, but the impacts on meiobenthic animals have received little attention. Tardigrades are microscopic metazoan lobopodians that are ubiquitous in benthic communities worldwide, but little is known about marine tardigrades in Central America. Only two marine tardigrades have been identified to species level in all of Central America, and these came from a single sample of barnacles from El Salvador collected in 1953. Additionally, multiple haplotypes of Echiniscoides were reported from Costa Rica and Panama, but species names were not assigned. Here we report an extensive survey of both intertidal and subtidal marine tardigrades from both the Caribbean and Pacific coasts of Costa Rica. We found 701 individuals in 65 samples. There was a total of 19 taxa, including seven species with a sufficient quality and quantity of specimens to describe here as new to science. The new species are Archechiniscus murilloi sp. nov., Batillipes homocercus sp. nov., Batillipes ichthyocercus sp. nov., Echiniscoides costaricensis sp. nov., Echiniscoides ritavargasae sp. nov., Styraconyx vargasi sp. nov. and Tanarctus breedyae sp. nov. Ten taxa were found only in the Caribbean, six were found only in the Pacific, and three were found on both coasts. We discuss the three species with trans-isthmus distributions and note two additional candidate geminate species pairs that warrant further investigation.

KEYWORDS:

• Meiofauna
• water bears
• Tardigrada
• biogeography
• biodiversity

Acknowledgements

This research was made possible by a Fulbright Specialist award to the lead author. We thank the University of Costa Rica’s Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) for their support and hospitality. The collecting trip to Guanacaste contributed to the marine bioinventory occurring in the Área de Conservación Guanacaste (BioMar-ACG project), and we thank that programme for its support including the masterful and cheerful field assistance of local parataxonomists Yelva Vega Gutierrez and Gilberth Ampie Cruz. Maribelle Vargas from the University of Costa Rica kindly verified the presence of diatoms on the cuticle of Tanarctus, and Jeffrey Sibaja from UCR identified the invertebrate substrates. We thank Warren Wilson College alumnus James Kitchens for the map in Figure 1 and for his brilliant work on the new version of the Interactive Map of Marine Tardigrades referenced throughout this paper. Research was conducted under permits ACLAC-216-2018 for the Caribbean coast, and ACG-PI-040-2017 for the Pacific coast.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

PB was partially funded by a Fulbright Specialist award (Project ID P001104). PF was partially funded by Fundação para a Ciência e Tecnologia (FCT) through the strategic project UID/MAR/04292/2019 granted to MARE. Further financial support came from the University of Costa Rica’s Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) and the BioMar-ACG project.