Contribution to the knowledge of the genus Plenotocepheus (Acari, Oribatida, Otocepheidae)

The oribatid mite genus Plenotocepheus (Oribatida, Otocepheidae) is recorded for the first time in the Antilles; one new species is described from the mould in the chimney of a deep cave of the Gaspar Grande Island, Trinidad. Plenotocepheus (Plenotocepheus) trinidadensis n. sp. differs from its most similar congener P. (Plenotocepheus) neotropicus Ermilov, Sandmann, Marian and Maraun, 2013 by the length of some notogastral setae and number of notogastral condyles. Generic and subgeneric diagnoses and an identification key to the known subgenera and species of Plenotocepheus are presented.

Among the oribatid mite material collected from cave of the Gaspar Grande Island, Trinidad, I found a new species of Plenotocepheus. This genus is recorded for the first time in the Antilles. The main goal of the paper is to describe and illustrate this species, update generic and subgeneric diagnoses and give an identification key to known taxa of Plenotocepheus.

Material
-Holotype (male) and two paratypes (both males): Trinidad, 10°39'51.10"N, 61°39'53.79"W, Gaspar Grande Island, limestone, chimney of 20 m deep cave with a few shrubs and trees around (shade), decay of Clusia on clayish soil, mould, 11.I.1955. Material was collected by Dr. P.W. Hummelinck (1907Hummelinck ( -2003 during his voyages in the Antilles, and sorted by Dr. M. Sellnick (1884-1971. Methods -Specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. The body length was measured in lateral view, from the tip of the rostrum to the posterior edge of the ventral plate. Notogastral width refers to the maximum width in dorsal aspect. Lengths of body setae were measured in lateral aspect. All body measurements are presented in micrometers. Formulas for leg setation are given in parentheses according to the sequence: trochanter-femur-genu-tibia-tarsus (famulus included). Formulas for leg solenidia are given in square brackets according to the sequence: genutibia-tarsus. Morphological terminology used in this paper follows that of F. Grandjean: see Travé & Vachon (1975) for general references, Norton (1977) for leg setal nomenclature, and Norton & Behan-Pelletier (2009) for overview. Drawings were made with a camera lucida using a Carl Zeiss transmission light microscope "Axioskop-2 Plus".

Subgeneric diagnosis
Costulae reaching the insertions of lamellar setae. Notogaster with 14 pairs of setae.
Type deposition -The holotype is deposited in the collection of the Netherlands Centre for Biodiversity Naturalis, Leiden, The Netherlands; two paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia.
Etymology -The specific name trinidadensis refers to Trinidad, where the new species was collected.
Remarks -Plenotocepheus (Plenotocepheus) trinidadensis n. sp. is morphologically most similar to P. (Plenotocepheus) neotropicus Ermilov, Sandmann, Marian and Maraun, 2013 from Ecuador in the absence of medial notogastral condyles, presence of long interlamellar and bothridial setae and well-developed notogastral setae, but differs by the notogastral setae c 1 and da distinctly shorter than c 2 and la (versus similar in length) and the absence of lateral notogastral condyles (versus developed).

DISTRIBUTION
At present, the known representatives of the genus Plenotocepheus are registered in Ecuador (1 species), Republic of Trinidad and Tobago (Trinidad) (1 species), Chile (Juan Fernández Islands) (1 species), Zimbabwe (1 species), South Africa (6 species), India (1 species) and New Zealand (3 species) (Fig. 4). Thus, three species were registered in the Neotropical region, seven species in southern Ethiopian region, one in the Oriental region and one in the Australian region. Each species was recorded in a single country, often only from the type locality, except Plenotocepheus (Plenotocepheus) verrucosus Grob-