New Species of the Genus Cheiroseius (Acarina, Parasitiformes, Gamasina, Ascidae) from Tropical Rain Forests of Ecuador, South America
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88 (3) · December 2016 pp. 165–174 New species of the genus Cheiroseius (Acarina, Parasitiformes, Gamasina, Ascidae) from tropical rain forests of Ecuador, South America Wolfgang Karg † and Anita Schorlemmer1,* 1 Department of Cell Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu HI 96813, USA * Corresponding author, e-mail: [email protected] Received 20 April 2016 | Accepted 16 November 2016 Published online at www.soil-organisms.de 1 December 2016 | Printed version 15 December 2016 Abstract The present studies continue our acarological investigations of soil inhabiting Parasitiformes from South and Central America. We discovered very remarkable species of the genus Cheiroseius Berlese, 1916 (Gamasina, Ascidae) from Ecuador. We explain the function of special organs of Cheiroseius and outline the significance of Parasitiformes in soil biology. Two new species of the subgenus Cheiroseius Berlese, 1916 s. str. and three new species of the subgenus Episeius Hull, 1918 are described and illustrated. Diagnoses of the genus Cheiroseius and the subgenera are given. We further generate keys for known and new species of the Cheiroseius tennesseensis-complex and the Cheiroseius necorniger-complex. Keywords Acari | Ascidae | new species | taxonomy | keys for determination | functional relations | bio-indicator 1. Introduction habitats (Krantz & Walter 2009). They orient themselves by moving leg I up and down. Leg I is equipped with Fundamentals. Over the last decades, our soil- apical thin tactile setae and tubular setae which allow zoological studies focused on the analysis of soil samples for the receiving of chemical and olfactory stimuli (Fig. from South and Central America (Karg 1994, 1997, 2003, 1A). Simultaneously, special ambulacra with lobate 2006, 2007, Karg & Schorlemmer 2009, 2011). The late pulvilli of leg II to IV enable the mites to move over the A. Zicsi, formerly University of Budapest, sent us samples moist substrata (Fig. 1B). The chelicerae are formed like from Acarina, cohors Gamasina. As an essential basis for tweezers (Fig. 2). With these mouth parts, the animals these studies served the internationally compiled annual are able to pull out Nematodes from moist substrates. series Bibliographia Acarologica, published by Axel Species of Cheiroseius are specialized in this type of Christian from the Senckenberg Museum für Naturkunde prey (Karg 1962, 1968, 1973). Further, the prominently Görlitz. These studies also show that systematics by developed peritremes of Cheiroseius are remarkable Kranz & Walter are not always based on phylogenetic (Figs 5, 6, 7). They allow respiration under very wet findings but convergent similarities (Note by Christian & conditions of the soil strata. Karg 2006: The predatory mite genus Lasioseius, p. 102). The genus was revised by Evans & Hyatt (1960), Genus Cheiroseius. Species of Cheiroseius prefer Karg (1981, 1998), chaetotaxy after Evans (1963). Karg moist habitats located near brooks or pools in moss (1981) divided the genus into two subgenera: subgenus or litter (Karg 1981, 1982, 1998). Adult females of Cheiroseius Berlese, 1916 s. str. and subgenus Episeius Cheiroseius are phoretic on flies colonizing these Hull, 1918 (Syn.: Posttrematus Karg, 1981). Dividing © Senckenberg Museum of Natural History Görlitz · 2016 ISSN 1864-6417 (print) · ISSN 2509-9523 (digital) 166 Wolfgang Karg & Anita Schorlemmer the genus taxonomically activated an old synonym of 3. Results Cheiroseius: Episeius Hull, 1918. This old name has priority and is used for the new subgenus. Genus Cheiroseius Berlese, 1916 According to soil biology, the presence of this genus represents a suitable bio-indicator for decaying Typus species: Sejus viduus C. L. Koch, 1839 processes under wet and damp conditions (Karg 1982). We have found species of the genus in high numbers in Diagnosis: Ambulacra of Legs II-IV well developed, soils of tropical rain forests, both, high in numbers of each leg consists of a pair of claws and three slender individuals as well as species, compared to European pulvilli markedly pointed, an adaptation for movement habitats (Karg 1998). over a moist substratum, relevant chaetotactic formulae In samples from Ecuador, the genus Cheiroseius of legs refer to tibia IV: X-type 2-1/1,3/1-2 and genu IV: proved especially species-rich (Karg 1998). The number IX-type 2-2/1,3/0-1, chelicerae formed like tweezers. of individuals was relatively low. Nine sample sites Particularly characteristic are the serrated cross-ledges of contained 17 species, of which 16 were novel species. In the hypostom without lateral borders (Karg 1993, p. 269, the present analysis, the last three samples of this series Fig. 202 d), valid for all embryonal states. Note: While were assessed. Five new species were described. characteristic for the genus, the hypostom is not relevant for the distinction of species. 1. Subgenus Cheiroseius Berlese, 1916 s. str. Diagnosis: Stigma situated between coxae III and 2. Material and methods IV, peritreme without posterior prolongation or with a short respectively slender posterior prolongation at most Prior to studying, the mites are treated with a mixture extending to about the middle of coax IV. of hot glycerine and acetic acid. Subsequently, they 2. Subgenus Episeius Hull, 1918 (Syn.: Posttrematus are mounted in glycerine, studied and drawn. For Karg, 1981) preservation, the Holotypes and paratypes are mounted Diagnosis: Stigma situated between coxae III and IV, in polyvinyl-lactophenol. The chaetotaxy of dorsum and peritreme with distinct posterior prolongation reaching venter follows Christian & Karg (2008). beyond the posterior margin of coxa IV. Deposition of types: Holotypes and paratypes We detected two new species that belong to the are deposited in the Acarological Collection of the Subgenus Cheiroseius Berlese, 1916 s. str. and three new Senckenberg Museum für Naturkunde Görlitz. species that belong to the Subgenus Episeius Hull, 1918. Figure 1. Ambulacra of tarsi, (A) at tarsus I with thin tactile setae Figure 2. Chelicerae of females: (A) Cheiroseius macrotarsus n. sp.; – 43 to 68 µm long; (B) at tarsi II, III, IV with slender and markedly (B) Cheiroseius christiani n . sp. (see text for measuring values). acute pulvilli – 37 to 47 long; (A) female of Cheiroseius christiani n. sp. (B) female of Cheiroseius macrotarsus n. sp. SOIL ORGANISMS 88 (3) 2016 New species of the genus Cheiroseius from tropical rain forests of Ecuador, South America 167 3.1. Subgenus Cheiroseius Berlese, 1916 s. str. Legs: I = 270, II = 209, III = 174, IV = 296 µm long corresponding to an idiosoma of 310 µm length, all of the Cheiroseius stigmaticus n. sp. tarsi with paired claws, at leg I shorter, tarsus I = 87 µm, tibia I = 44 µm long, setae mostly very short, apical Material examined: Holotypus ♀. Ecuador, 1987, touch-setae at tarsus I longer: 25–26 µm long. relevant Province Napo, Pusono, on the left banks of Rio Pusono, chaetotactic formulae of legs refer to tibia IV: X-type 300 m a.s.l., moss from tree stems, in the rainforest. 2-1/1,3/1-2 and genu IV: IX-type 2-2/1,3/0-1 (Fig. 3D). Etymology: As to the extremely large stigma. Diagnosis: Leg I shorter than the length of idiosoma, tarsus I longer than tibia I, ventrianal shield bearing 5 Cheiroseius zicsii n. sp. pairs of setae, middle prolongation of the tectum nearly three times the length of the lateral prolongations, stigma Material examined: Holotypus ♀. Ecuador, 1987, extremely large, ventrianal shield some wider as long. Province Napo, Pusono, on the left banks of Rio Pusono, Description: Idiosoma ♀ 310 × 218 µm, oval, color 300 m a.s.l., moss from tree stems, in the rainforest. brown. Etymology: We name the species in honor of the late Dorsum: Surface of the pro-dorsum reticulated, setae A. Zicsi from the research team of the University of at the vertex 7–9 µm long, at the middle of the shield 20– Budapest who has sent us mites from South and Central 30 µm long, most of dorsal setae 30–35 µm long and arise America for our investigations of Parasitiformes. from small protuberances (Fig. 3A). Diagnosis: Leg I shorter than the length of idiosoma, Venter: Ventrianal shield pentagonal, 129 µm wide, tarsus I longer than tibia I, stigma extremely large, 95 µm long, bearing 5 pairs of setae, 15–17 µm long, sternal shield with a reticulated area medially, ventrianal postanal seta only 10 µm long, genital shield nearly as shield distinctly wider than long, width : length = 5 : 3 long as wide, genital setae 15 µm long, setae of the sternal and bearing 5 pairs of setae, middle prolongation of the shield 22 µm long, peritremes slender with a small, very tectum remarkably longer than the lateral prolongations. short prolongation, however the stigma extremely large, Description: Idiosoma ♀ 336 × 210 µm, oval, color in diameter as the anus, broad (Fig. 3B). brown. Gnathosoma: Tectum with three prongs which are Dorsum: Surface of the pro-dorsum reticulated, setae forked apically, middle prong = 16 µm, lateral prongs = at the vertex 8 µm long, at the middle of the shield 30 µm 6 µm long (Fig. 3C). Digitus mobilis of the chelicerae long, most of dorsal setae 31–35 µm long and arise from with two teeth, digitus fixus with three teeth. small protuberances (Fig. 4A). Figure 3. Cheiroseius stigmaticus n. sp. female, (A) dorsum; (B) venter; (C) tectum; (D) leg I (see text for measuring values). SOIL ORGANISMS 88 (3) 2016 168 Wolfgang Karg & Anita Schorlemmer Venter: Sternal shield with a reticulated area medially,