Abstract The Sierra Nevada de Santa Marta (SNSM) is a mountain range in northern Colombia, recognized for its high biological richness. To date, the existence of 27 species of tardigrades is known for this particular region. Morphological and morphometric analysis of 51 specimens, found in 16 samples of bryophytes and lichens collected at the SNSM, and deposited in the tardigrade collection of the “Centro de Colecciones Científicas de la Universidad del Magdalena” between 2011 and 2016 was carried out. The species Mixibius gibbosus sp. nov. is described based on the following main traits: presence of gibbosities (up to date never reported for any species of the genus Mixibius), isodiametric tubercles and relevant morphometric differences with respect to the most similar congeneric species. Additionally, the species Diphascon pingue pingue sensu lato, Hypsibius cf. allisoni and Adropion onorei are, for the first time, recorded for Colombia and the latter is recorded for the first time out of Ecuador. All records are new for the SNSM.

Abstract: The new species Minibiotus pentannulatus sp. nov., is described from the Sierra Nevada de Santa Marta, Colombia. It differs from the other species of the genus by star-shaped pores, the presence of a peculiar egg with a smooth shell, and small conical processes with 5 annulations. Other differences include the distribution and size of the pores, and other morphometric details regarding the size of the body and buccal tube, and the pt of the stylet support insertion point, macroplacoids and claws. To date, the genus Minibiotus R.O. Schuster, 1980, comprises 48 species, including the species described here.

Resumen: Se describe la nueva especie Minibiotus pentannulatus sp. nov., proveniente de la Sierra Nevada de Santa Marta, Colombia. Ésta difiere de las otras especies del género por los poros en forma de estrella, la presencia de huevos característicos con cáscara lisa y procesos cónicos con 5 anillos. Otras diferencias incluyen la distribución y talla de los poros y otros detalles morfométricos. Hasta la fecha, el género Minibiotus R.O. Schuster, 1980, comprende 48 especies, incluyendo la especie aquí descrita.

Los tardígrados son un grupo de micrometazoos pobremente estudiados en Colombia. Su conocimiento se limita a unos pocos trabajos taxonómicos realizados principalmente en la región Andina del país. Con el objetivo de incrementar el conocimiento de su distribución y diversidad, en este trabajo se presenta un catálogo taxonómico, una clave para la identificación de géneros y los registros fotográficos de las especies encontradas en la parte baja de las cuencas de los ríos Manzanares y Gaira, Santa Marta. 215 especímenes fueron encontrados en muestras de musgos, hepáticas y líquenes sobre rocas y cortezas de árboles. 13 especies fueron identificadas, pertenecientes a ocho géneros de las familias Echiniscidae, Macrobiotidae, Milnesiidae e Isohypsibidae. El género Calcarobiotus y las especies Doryphoribius quadrituberculatus y Milneisum katarzynae son registrados por primera vez para Colombia.

Tardigrades are a group of poorly studied micrometazoans in Colombia. Its knowledge is limited to few taxonomic surveys carried out mainly in the Andean region of the country. With the aim of increasing the knowledge about its distribution and biodiversity a taxonomic checklist, a taxonomic key for genera, and photographic records of tardigrades from the lower Manzanares and Gaira river basins are presented in this work. 215 specimens were found in samples of mosses, liverworts, and lichens on rocks and tree bark. 13 species belonging to eight genera and to the families Echiniscidae, Macrobiotidae, Milnesiidae and Isohypsibidae were identified. The genus Calcarobiotus and the species Doryphoribius quadrituberculatus and Milneisum katarzynae are recorded for the first time in Colombia.