Research Article |
Corresponding author: Ricardo Pinto-da-Rocha ( ricrocha@usp.br ) Academic editor: Adriano Kury
© 2015 Ricardo Pinto-da-Rocha, Rafael Fonseca-Ferreira, Maria Bichuette.
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:
Pinto-da-Rocha R, Fonseca-Ferreira R, Bichuette ME (2015) A new highly specialized cave harvestman from Brazil and the first blind species of the genus: Iandumoema smeagol sp. n. (Arachnida, Opiliones, Gonyleptidae). ZooKeys 537: 79-95. https://doi.org/10.3897/zookeys.537.6073
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A new species of troglobitic harvestman, Iandumoema smeagol sp. n., is described from Toca do Geraldo, Monjolos municipality, Minas Gerais state, Brazil. Iandumoema smeagol sp. n. is distinguished from the other two species of the genus by four exclusive characteristics – dorsal scutum areas with conspicuous tubercles, enlarged retrolateral spiniform tubercle on the distal third of femur IV, eyes absent and the penial ventral process slender and of approximately the same length of the stylus. The species is the most highly modified in the genus and its distribution is restricted only to caves in that particular area of Minas Gerais state. The type locality is not inside a legally protected area, and there are anthropogenic impacts in its surroundings. Therefore, Iandumoema smeagol sp. n. is vulnerable and it must be considered in future conservation projects.
Endemism, troglobitic, limestone, Espinhaço Supergroup, Minas Gerais state
The subterranean or hypogean fauna is ecologically categorized according to the degree of the populations’ dependence and specialization to that environment, as proposed by
In caves, harvestmen are found near to or in association with organic matter deposits or spots, under blocks and rocks, on the walls, and on the ceiling, exhibiting solitary or gregarious behavior (
The gonyleptid genus Iandumoema
A new cave species of Iandumoema is herein described, being the second troglobitic harvestman with no eyes for Brazil (the first being the GonyleptidaeGiupponia chagasi Perez and Kury 2002, from Serra do Ramalho karst area, Bahia state, northeastern Brazil). This record corroborates the hypothesis of an exclusively troglobitic genus.
Iandumoema smeagol sp. n. is recorded from two caves from Monjolos region, Minas Gerais State, Brazil. This region is located in the central east part of the southern portion of the São Francisco Craton, Velhas river basin, with a mean altitude of approximately 600 meters, inserted in the Sete Lagoas Formation, Bambuí Group, which has a relief typical of karst carbonate regions (
Toca do Geraldo is a limestone cave which extends approximately 1.5 km, with one entrance in a crack (Figure
The type material were collected, fixed in 70% ethanol and examined under a stereomicroscope. Live specimens were collected to observe the coloration in vivo. We took photographs and length measurements using a Leica stereomicroscope (M205C). Methods and terminology follow
In the natural habitat, through ad libitum method (
1 | Apophysis of coxa IV directed obliquely backwards (parallel to body main axis) | 2 |
– | Apophysis of coxa IV directed laterally (perpendicular to body main axis) | I. uai |
2 | Dorsal scutum areas with conspicuous tubercles (paramedian pair higher than wide), retrolateral trochanter IV with larger tubercle on apex | I. smeagol sp. n. |
– | Dorsal scutum areas with low tubercle (as heigh as wide), retrolateral trochanter IV without larger tubercle on apex | I. setimapocu |
Male holotype, Brazil, Minas Gerais, Monjolos, Toca do Geraldo cave, S18°16'43.31", W44°06'10.96’, 08.VII.2014, R. Fonseca-Ferreira, M.E. Bichuette, I. Arnone and J.E. Gallão leg. (
The specific epithet refers to the hobbit named Smeagol, created by J.R.R. Tolkien, being the original name of Gollum – the dweller of the caves located below the Misty Mountains of Middle-earth of the Lord of the Rings book.
Iandumoema smeagol sp. n. can be distinguished from other Iandumoema species by the following exclusive characteristics: dorsal scutum areas with conspicuous tubercles (paramedian pair much higher than wide), enlarged retrolateral spiniform tubercle on the distal third of femur IV, eyes absent and the penial ventral process slender and of approximately the same length as the stylus – and by the combination of the following characters: four pairs of macrosetae on penial basal group A+B (six in I. uai), three or four pairs of macrosetae on penial distal group C (six pairs in I. uai); and the apex of the penial truncus narrower than ventral plate basal width (wider in I. uai), and the setae of male pedipalpal tibia ectally and mesally with IiIi (ectally with IiiIi and mesally with IiIi in I. setimapocu). A more detailed comparison of morphological and meristic features of Iandumoema species are provided in Table
Comparative morphological and meristic data for the three Iandumoema species from Brazilian caves (adapted from
Characters | I. uai Pinto-da-Rocha, 1996 | I. setimapocu Hara & Pinto-da-Rocha, 2008 | I. smeagol sp. n. |
---|---|---|---|
Eyes condition | At least twice the diameter of tubercles on carapace | Same or similar size of diameter of tubercles on carapace | Absent |
Setae on male pedipalpal tibia | Ectally and mesally with IiIi | Ectally with IiiIi and mesally with IiIi | Ectally and mesally with IiIi |
Direction of dorso-apical apophysis on male coxa IV | Backwards and laterally | Obliquely backwards, close to body | Obliquely backwards, close to body |
Submedian prolateral apophysis on male trochanter IV | Absent | Present | Present |
Large tubercles on dorsal male femur apex | Two (one prolaterally, the other retrolaterally) | Three (two as in I. uai, plus a large median one) | Two (one prodorsal and one median) |
Number of pair of macrosetae on penial basal group (A+B) | 6 | 4 | 4 |
Number of pairs of macrosetae on penial distal group (C) | 3 | 4 | 3–4 |
Shape of penial ventral process | Short and serrate | Short and serrate | Slender and approx. same length as stylus, not serrate |
Apex of penial truncus | Wider than ventral plate basal width | Narrower than ventral plate basal width | Narrower than ventral plate basal width |
Iandumoema smeagol sp. n., measurements (in mm) of appendages of male paratype (
Tr | Fe | Pt | Ti | Mt | Ta | Total | |
---|---|---|---|---|---|---|---|
Leg I | 0.3 (0.4) | 3.9 (3.0) | 1.1 (0.8) | 2.9 (2.1) | 4.8 (3.5) | 2.5 (2.1) | 15.5 (11.9) |
Leg II | 0.5 (0.3) | 8.1 (5.3) | 1.5 (1.3) | 6.8 (5.1) | 9.2 (6.1) | 6.9 (5.2) | 25.7 (23.3) |
Leg III | 0.6 (0.3) | 5.4 (3.9) | 1.3 (0.8) | 3.1 (2.2) | 5.5 (4.1) | 2.3 (1.5) | 18.2 (12.8) |
Leg IV | 1.1 (0.5) | 6.9 (5.5) | 2.0 (1.5) | 5.2 (3.8) | 7.4 (6.1) | 2.2 (2.3) | 24.8 (19.7) |
Pedipalp | 0.6 (0.4) | 2.1 (1.5) | 0.9 (0.8) | 1.6 (1.1) | --- | 1.1 (0.9) | 6.3 (4.7) |
Male: Dorsum (Figures
Venter (Figure
Chelicera: Segment I elongated, bulla poorly defined, with four tubercles. Fixed finger with four equally sized teeth on the edge; movable finger with five teeth.
Pedipalps (Figure
Legs (Figures
Femur IV straight, with two rows of irregular dorsal tubercles, two ventral rows of higher than others of same segment (twice as long as wide) tubercles on apex, one retrolateral row of irregular-sized tubercles, larger than other of same segment (third apical one largest), two enlarged dorso-apical tubercles (one prodorsal and one median). Patella IV with two ventral rows of tubercles, tuberculate on the sides, dorsally unarmed. Tibia IV with two rows of ventral tubercles of similar sizes. Basitarsus I of similar size as distitarsus. Tarsal segmentation: 6(3), 11(3), 6, 6.
Penis (paratype
(Figures
Female (paratype, LES/UFSCar 0006299, Figure
Iandumoema smeagol sp. n. seems to be close related to I. setimapocu based on number of macrosetae on penis, four pairs on group A+B (six in I. uai) and apex of truncus narrower than ventral plate basal width. The shape of male apophysis on coxa IV is similar in both species, being obliquely directed, as also the presence of a submedian prolateral apophysis on male trochanter IV. However, a cladistics analysis is necessary to reveal well-supported relationships among Iandumoema species.
The occurrence of Iandumoema smeagol sp. n. in the limestone caves of Bambuí Group, more specifically in the boundaries of Serra do Espinhaço Plateau (Figure
As a result of their faunistic singularities and high endemism, hypogean environments are considered fragile. Besides their unique faunistic composition, the singularity of cave habitats is related to the presence of relicts, many times represented by troglobitic species.
We are greatly indebted to: the field team, B.G.O. do Monte, C.S. Fernandes, I. Arnone and J.E. Gallão; M.P. Bolfarini for preparing the drawing of male habitus; the Instituto Nacional de Ciência e Tecnologia (INCT) of Hymenoptera parasitoids in the southeast of Brazil for permission to use the stereomicroscope Leica DFC 295 and L.B. Fernandes (UFSCar technician) for capturing the images; A.T. Fushita for preparing the map of the study area. The field trips were funded by the Programa de Pós-graduação em Biologia Comparada (PPGBC/USP) and Programa de Pós-graduação em Ecologia e Recursos Naturais (PPGERN/UFSCAR). M.E. Bichuette has been funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, 303715/2011-1), R. Pinto-da- Rocha has been funded by Fundação de Amparo à Pesquisa do Estado e São Paulo (FAPESP, 2012/02969-6 and 2013/50297-0), the National Science Foundation (NSF/DOB 1343578) and NASA. To Cibele Bragagnolo and Marcos Hara for the carefully revision on the first draft of the manuscript.