Nematodes of soft bottoms from the ‘Po’ol Tunich’ cave system, Quintana Roo, Mexico

ABSTRACT

The Yucatán Peninsula is a vast karst platform that hosts superficial ecosystems such as sinkholes or underground cave systems. This study aims to give the first nematode species list for and explain their distribution at the Po´ol Tunich cave system. Samplings were carried out from September 2015 to February 2016, at five sampling sites along the cavern system. At each site, two sediment samples were collected with a polyvinylchloride pipe (PVC) corer; sediments were processed by decantation, and meiofauna was collected with a 45 µm sieve. Nematodes were picked manually, mounted on glass slides and identified. At three sites (1, 3 and 5), water temperature and electric conductivity were measured with HOBO data loggers. The nematode fauna was represented by six orders, nine families and 12 genera. Enoplida and Chromadorida have the highest number of species (three each), while Rhabditida and Plectida have two species each. There was only one species of Dorylaimida. Sites with the highest abundance were: 1 (25 organisms) and 2 (24 organisms), with Atrochromadora sp. as the most abundant species, followed by Ironus paludicola, Hoplolaimus tylenchiformis and Dichromadora sp., at five organisms each. The four types of nematode feeding were present, with a predominance of epistrate and deposit feeders, followed by chewers and then suction feeders, and this fact is an indicator of the food resources available in the cave. Our results reveal that nematodes are an important component in the cave fauna, and they exploit the resources available based in detritus. Further efforts are needed to understand the nematode communities associated with subterranean environments.

KEYWORDS:

• hydrology
• karst
• meiofauna
• tourism
• underground caves

Acknowledgements

The first author thanks Jose Juan Oliva Rivera and Abel Vargas for their collaboration on the sample collection, and the staff of Rio Secreto, who provided field guide help and equipment. The comments of two anonymous reviewers substantially improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Geolocation information

20°35´19.17”N, 87°8´5.72”W

Additional information

Funding

This work was supported by El Colegio de la Frontera Sur, Departamento de Sistemática y Ecología Acuática [grant number 09/2015-04].