Two new species of oribatid mites of the genus Truncozetes (Acari, Oribatida, Epactozetidae) from Ecuador

Abstract Two new oribatid mite species of the genus Truncozetes (Oribatida, Epactozetidae), Truncozetes ecuadoriensis sp. n. and Truncozetes monodactylus sp. n., are described from the Ecuadorian soils. The morphology of the gnathosoma and the legs is presented in detail for the first time for the species of Truncozetes. An identification key to all known species of the family Epactozetidae is given.

Epactozetes is a genus that was proposed by Grandjean (1930) with Epactozetes imitator Grandjean, 1930 as type species. Currently, this genus comprises two species: Epactozetes imitator Grandjean, 1930(see Grandjean 1930) and E. setosus Balogh and Mahunka, 1969 (see Balogh and Mahunka 1969b). The main diagnostic characters of this genus are (summarized from Balogh andBalogh 1988, 1992; with our opinions): lamellae as long as prodorsum, fused or connected medio-anteriorly; genital plates with five pairs of setae; leg tarsi with three claws.
Truncozetes is a genus that was proposed by Balogh and Mahunka (1969a) with Truncozetes mucronatus Balogh and Mahunka, 1969 as type species. Currently, this genus comprises three species: Truncozetes mucronatus Balogh and Mahunka, 1969 (see Balogh and Mahunka 1969a), T. rugosus Mahunka, 1998 (see Mahunka 1998) and T. sturmi Balogh, 1984(see Balogh 1984. The main diagnostic characters of this genus are (summarized from Balogh and Mahunka 1969a;Balogh andBalogh 1988, 1992; with our opinions): lamellae shorter than prodorsum, well separated, connected by translamella; notogaster with large posterior tubercle; genital plates with five to six pairs of setae; leg tarsi with one or three claws (one species with monodactylous legs I and tridactylous legs II-IV).
During taxonomic identification of the Ecuadorian oribatid mite fauna, we discovered two new epactozetid species belonging to the genus Truncozetes. The main purpose of this paper is to describe and illustrate these species under the names Truncozetes ecuadoriensis sp. n. and T. monodactylus sp. n. The morphology of the gnathosoma and the legs is presented in detail for the first time for the species of the genus Truncozetes.
An identification key to all known species of the family Epactozetidae is provided.

Materials and methods
Specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. Body length was measured from the side, i.e. 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 from the lateral side. All body measurements are given in micrometers (μm). Formulae for leg setation are given in parentheses according to the sequence trochanter-femur-genu-tibia-tarsus (famulus included). Formulae for leg solenidia are given in square brackets according to the sequence genu-tibia-tarsus. General terminology used in this paper follows that summarized by Norton and Behan-Pelletier (2009).
Legs. Tarsus I with one claw, tarsi II-IV with three claws. Dorsal side of tarsus I and dorso-proximal part of tibia IV with strong thorn (t); antero-ventral side of genu I  Table 1. Famulus (e) thin, straight, inserted anteriorly to thorn. Setae barbed (except smooth p and s on tarsus I). Solenidia ω 1 on tarsus I, ω 1 , ω 2 on tarsus II, σ on genua III thickened, blunt-ended, other solenidia setiform. Etymology. The specific name "ecuadoriensis" refers to the country of origin, Ecuador.

Remarks.
The new species is clearly distinguishable from other known species of the genus Truncozetes by the different number of leg claws (leg I monodactylous, legs II-IV tridactylous versus all legs monodactylous or tridactylous). Additional distinctive characters of a new species with the other species of the genus can be found in the identification key given below. Description. Measurements. Body length: 232 (holotype and paratype), 166 (holotype and paratype).
Legs. Similar to Truncozetes ecuadoriensis sp. n., but all tarsi with one strong claw.   Etymology. The specific name "monodactylus" refers to the one claw on all leg tarsi. Remarks. The new species is clearly distinguishable from other known species of the genus Truncozetes by the monodactylous legs (versus all legs tridactylous or leg I monodactylous, legs II-IV tridactylous). Additional distinctive characters of this species from other species of the genus can be found in the identification key given below.