Research Article |
Corresponding author: Leopoldo Ferreira de Oliveira Bernardi ( leopoldobernardi@gmail.com ) Academic editor: Oana Teodora Moldovan
© 2018 Leopoldo Ferreira de Oliveira Bernardi, Elmir Lúcio Borges-Filho.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Bernardi LFO, Borges-Filho EL (2018) Neocarus spelaion sp. n. (Parasitiformes, Opilioacaridae), a new species of cave dwelling Neocarus from Minas Gerais state, Brazil. Subterranean Biology 27: 1-16. https://doi.org/10.3897/subtbiol.27.25777
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A new cave dwelling species of the genus Neocarus (Parasitiformes: Opilioacarida: Opilioacaridae) is described from adult females and males collected in Minas Gerais state, southeast Brazil. Five or six d-type setae on palps, females with pregenital area hairless, genital setae smooth, cylindrical ovipositor with two terminal lobes, and males with genital and pregenital setae variable in shape, some being smooth and pointed, others ribbed and pointed, are the combinations of characters that define the new species.
Opilioacarida , Hypogean, Neotropical
The order Opilioacarida presently includes 13 genera, 47 described species and one sub-species. Of these, only four genera, but more than half of all species and the described subspecies are from the New World. (
The species of opilioacarid described in this present study was observed in caves located in karst areas in Minas Gerais state, Brazil (Fig.
All specimens were collected by hand from caves, searching under stones, in accumulations of organic matter, cracks in the soil and were stored in vials with 70% ethanol. Posteriorly, all specimens were prepared as slide-mounted specimens. For this purpose, specimens were dissected (due to size), cleared in Nesbitt’s solution, and mounted on slides using Hoyer’s medium (
Drawings were prepared using a Zeiss Axioscope 3 phase contrast microscope, connected to a drawing tube; and measurements were taken in the same scope and are presented in micrometers (µm). All measurements were taken from slide mounted specimens. Ultrastructural analyses were also conducted through use of scanning electron microscopy. A female was placed on an aluminium support stub covered with a film of aluminium foil with carbon tape, sputter-covered with gold (Baltec SCD 050), and observed in a LO EVO 40 XVP scanning electron microscope. The nomenclature of setae and other morphological characters follows
Specimens are deposited at the Mite Reference Collection, Department of Entomology and Acarology, Escola Superior de Agricultura “Luiz de Queiroz” (MZLQ), Universidade de São Paulo, Piracicaba, São Paulo, Brazil; Collection of Subterranean Invertebrates (ISLA), Section of Zoology, Department of Biology, Universidade Federal de Lavras, Lavras- MG, Brazil; Collection of the Acarology Laboratory (UFMG-AC), Department of Zoology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Holotype 1 female specimen deposited at MZLQ, Brazil, Minas Gerais, Matozinhos, Cave 013, 19°31'57.21"S, 44°5'30.30"W Datum WGS84, col. Filho et al., setember.2016, manual collection. Paratype 1 male specimen deposited at MZLQ, same data as holotype; paratype 1 male specimen deposited at ISLA, same data as holotype; 1 female specimen deposited at ISLA, same data as holotype; paratypes 1 male specimen deposited at MZLQ, Brazil, Minas Gerais, Matozinhos, Cave 053, 19°31'47.92"S, 44°5'33.51"W Datum WGS84, col. Filho et al., setember.2016, manual collection; 1 female specimen deposited at MZLQ, Brazil, Minas Gerais, Matozinhos, Cave 053, 19°31'47.92"S, 44°5'33.51"W Datum WGS84, col. Filho et al., setember.2016, manual collection; paratype 1 female specimen deposited at ISLA, Brazil, Minas Gerais, Matozinhos, Cave 093, 19°31'56.06"S, 44°5'34.70"W Datum WGS84, col. Filho et al., setember.2016, manual collection; paratype 1 female specimen deposited at UFMG-AC, Brazil, Minas Gerais, Matozinhos, Cave 010, 19°31'58.45"S, 44°5'31.05"W Datum WGS84, col. Filho et al., setember.2016, manual collection.
Noun in apposition. The specific epithet “spelaion” is in honor of the Spelayon, a group of speleologists and for their contribution to the knowledge of Brazilian subterranean biology and geospeleology.
Neocarus species are often identified by a combination of characters, mainly using palp, pregenital and genital setae, while the ovipositor shape is usually considered a species-specific character. A summary of the characters used for species definition is presented in Table
Comparative setal patterns for the pregenital and genital region of Neocarus adults.
Occurence | Species/Subspecies | Female | Male | Palp | |||
Pregenital region | Genital region | Pregenital region | Genital region | ch -type | d -type | ||
No. and type of setae | No. and type of setae | No. and type of setae | No. and type of setae | ||||
North America | |||||||
USA | N. texanus | 2 st/r | 0 | 4–6 st/r | 8–9 sh | 10–14(21a) | 5 |
Mexico | N. nohbecanus | nude | 0 | 4–5 st/r | 5–7st/r | 17–19 | 4 |
Mexico | N. siankaanensis | nude | 0 | 2 st/r | 4 st/r | 14–15 | 5 |
Mexico | N. bajacalifornicus bajacalifornicus | 2 st/r | 0 | 5–8(13a) st/r | 7–8(11a) st/r | 14–18 (21a) | 5 |
Mexico | N. bajacalifornicus chamelaensis | 2–3 st/r | 0 | 4–5 st/r | 4–6 st/r | 16 | 5 |
Mexico | N. calakmulensis | 2–3 st/r | 0 | 2–6 st/r | 3–8 st/r | 17 | 5 |
Mexico | N. veracruzensis | 2 st/r | 0 | 6–8 st/r, 0–1 s | 6–8 st/r | 13 | 5 |
Mexico | N. comalensis | 5–7 st/r | 3 st/r | 14–18 | 5 | ||
Mexico | N. chactemalensis | nude | nude | 4–6 st/r | 4–6 st/r | 11–13 | 4 |
Central America | |||||||
Nicaragua | N. nicaraguensis | 2–5 st/r | 0 | 2–7 st/r | 3–6 st/r | 18–22 | 5 or 6 |
Cuba | N. orghidani | nude | 0 | 4–5 st/r | 5–7 st/r | 20–24 | 4 |
South America | |||||||
Venezuela | N. ojastii | nude | 0 | 6–9 ? | 13 st/r | – | – |
Brazil | N. proteus | 2–5 st/r | 4–6 wb | 2–5 st/r | 3–5 sh | 12 or 13 | 5 or 6 |
Brazil | N. potiguar | 1 tp/r | 4–8 sh | 5 st/r | 7–10 st/r | 25–27 | 5 or 6 |
Brazil | N. coronatus | nude | 6–8 tp | 1–7 st/r | 5–15 tp/r | 18–25 | 4 |
Brasil | N. spelaion | nude | 10–12 sh | 9–12 sh or tp/r | 7–11 sh or tp/r | 14–18 | 5 or 6 |
Brazil/Argentina/Uruguay | N. platensis | 0–2 st/r | 6–9 sh | 6–10 st/r | 5–10 sh | 14 | 5 or 6 |
The definition of the species Neocarus spelaion sp. n. is given by; palp tarsus with 5 or 6 foliate setae (d-type); area between sternal and genital verrucae with two pairs of long, tapering setae; female with hairless pregenital area and 10-12 smooth genital setae, and ovipositor cylindrical, bare and with two terminal lobes. Male genital area with 7–11 setae, and pregenital area with 9–12 setae variable in shape, some of them smooth and pointed, or ribbed and pointed. Ovipositor with two terminal lobes and shape of setae on male pregenital and genital area are unique to N. spelaion sp. n.
Chelicera (Fig.
Neocarus spelaion sp. n. (Female): A Lateral view of chelicerae B Ventral view of subcapitulum C Detail of a seta with a fine tip D Detail of a seta with a rounded tip, found only in females (arrows in Fig. B). Abbreviations; cb1–4 = circumbuccal setae, pl1–4 = paralabial setae, ch = cheliceral setae, cht = basal segment seta, lb = labrum, id = dorsal lyrifissure, iα = antiaxial lyrifissure.
Subcapitulum (Fig.
Palp tarsus (Fig.
Idiosoma (Fig.
Sternitogenital region (Figs
Ovipositor when invaginated, consisting of a tube-like structure with two rounded and lateral lobs on tip, but when evagined these two lobs turn in a single structure, placed laterally to opening, without a eugenital setae. A single pair of gland-like structures in its median portion, and apex convex.
Legs (Figs
Acrotarsus of leg II with a dorsal bifurcate seta and two smooth sensilla (one long and other ωa small) resembling solenidia (Figure
The caves where the N. spelaion sp. n. was found receive large amounts of organic matter from the surrounding epigean system, which penetrates through skylights, gaps, cracks in the ceiling and at the main entrance. These caves contain a lot of loose rock, plus wide entrances, resulting in extensive photic zone in the hypogean environment, which enables the development of plant species in places near the entrance, providing a suitable place for shelter and permanence of Opilioacarida species (Fig.
The transport of organic matter from the epigean to the hypogean environment can be an important factor for the opilioacarid species to establish a population in the interior of caves. There have already been reports that this species group feeds on pollen, fungi hyphae, plant fragments and arthropods (
The Brazilian opilioacarids are widely distributed in karst regions, places where there is a great demand for mineral extraction. At least other 5 species, including a new genus, have been found in this formation, however, their descriptions have not yet been published (pers. observation).
The region of the Bambuí Geomorphological unit contains important limestone deposits and is under for intense pressure from mining activities, threatening caves and the surrounding epigean habitats (
The author sincerely thanks Spelayon Consultoria the speleologist group that provided all the specimens and cave information, including photos, present in this study. The author also thanks to ADESITA (“Agência de Desenvolvimento Econômico de Itabirito”) for funds provided through the Project (“Descrição e publicação científica sobre novas espécies troglóbias de ácaros identificadas no Estado de Minas Gerais a partir dos exemplares depositados na Coleção Taxonômica da UFMG (CT–UFMG); number: 04/2016”). LFOB scholarships were provided by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). Thanks also to the reviewers (Mark Harvey and Marce Santos Araújo) for their valuable suggestions.