A systematic revision of Goniosomatinae (Arachnida: Opiliones: Gonyleptidae), with a cladistic analysis and biogeographical notes

Abstract

Goniosomatine harvestmen have strongly armed pedipalps, generally large bodies and, commonly, very long legs (sometimes more than 20 cm), and are distributed in the Brazilian Atlantic forest, from southern Bahia to Santa Catarina. Since they are conspicuous animals and individuals of some species tend to concentrate in caves (and also under rock boulders), they have been (and still are) the target of several studies, especially those focusing on reproductive and defensive behavior, population ecology, physiology, chromosomes, etc. In spite of their importance for biological studies (some species constitute important and frequently used models for these studies), the taxonomy of Goniosomatinae has faced some problems, including misidentification, a large number of undescribed species and the lack of a phylogenetic hypothesis for the relationships among its species (which would allow evolutionary studies to be made). The last taxonomic changes in the subfamily were made 60 years ago. Considering a taxonomic revision and cladistic analysis of the subfamily to be of paramount importance, the main scope of the present paper is to provide a cladistic analysis and taxonomic revision of the species of Goniosomatinae and a new arrangement of genera (and species). The main taxonomic changes are given as follows. Six genera are recognised within the subfamily: Goniosoma; the newly described genus Pyatan; the reestablished genera Serracutisoma, Heteromitobates and Mitogoniella; and Acutisoma. New generic synonyms include: Glyptogoniosoma = Goniosomella = Lyogoniosoma = Metalyogoniosoma = Xulapona = Goniosoma, Acutisomelloides = Pygosomoides = Spelaeosoma = Serracutisoma; and Acutisomella = Heteromitobates. Newly described species include: Goniosoma capixaba; G. apoain; Pyatan insperatum DaSilva, Stefanini-Jim & Gnaspini; Serracutisoma pseudovarium; S. fritzmuelleri; S. guaricana; Heteromitobates anarchus; H. harlequin; H. alienus; Mitogoniella taquara; M. unicornis; and Acutisoma coriaceum. New combinations include: Goniosoma macracanthum (Mello-Leitão, 1922); G. unicolor (Mello-Leitão, 1932); G. carum (Mello-Leitão, 1936); Serracutisoma proximum (Mello-Leitão, 1922); S. banhadoae (Soares & Soares, 1947); S. molle (Mello-Leitão, 1933); S. thalassinum (Simon, 1879); S. catarina (Machado, Pinto-da-Rocha & Ramires, 2002); S. inerme (Mello-Leitão, 1927); S. spelaeum (Mello-Leitão, 1933); Heteromitobates inscriptus (Mello-Leitão, 1922); H. albiscriptus (Mello-Leitão, 1932); Mitogoniella modesta (Perty, 1833); and M. badia (Koch, 1839). Reestablished combinations include: Mitogoniella indistincta Mello-Leitão, 1936 and Acutisoma longipes Roewer, 1913. New specific synonyms include: Acutisomella cryptoleuca = Acutisomella intermedia = Goniosoma junceum = Goniosoma patruele = Goniosoma xanthophthalmum = Metalyogoniosoma unum = Goniosoma varium, Goniosoma geniculatum = Goniosoma venustum; Goniosomella perlata = Progoniosoma minense = Goniosoma vatrax, Glyptogoniosoma perditum = Progoniosoma cruciferum = Progoniosoma tijuca = Goniosoma dentipes; Leitaoius iguapensis = Leitaoius viridifrons = Serracutisoma proximum; Acutisoma marumbicola = Acutisoma patens = Serracutisoma thalassinum; Progoniosoma tetrasetae = Serracutisoma inerme; and Acutisoma monticola = Leitaoius nitidissimus = Leitaoius xanthomus = Mitogoniella mutila = Acutisoma longipes. The following species are considered species inquirenda: Goniosoma lepidum Gervais, 1844; G. monacanthum Gervais, 1844; G. obscurum Perty, 1833; G. versicolor Perty, 1833; and Mitogoniella badia (Koch, 1839). The monotypic genus Goniosomoides Mello-Leitão, 1932 (and its species, G. viridans Mello-Leitão, 1932) is removed from Goniosomatinae and considered incertae sedis.

A new species of Serracutisoma (Opiliones: Gonyleptidae: Goniosomatinae) from the coastal Atlantic Rain Forest of Paraná and São Paulo states, Brazil

“…nov. also has spines on tibia II, located on row 3, as S. proximum does. Six other species of Serracutisoma have those spines, whose disposition on leg II varies widely from one species to another: S. banhadoae, row 2 of tibia and metatarsus, S. molle, rows 3 and 4 of tibia, S. thalassinum, rows 3 and 4 of tibia and metatarsus, S. catarina, rows 4 and 5 of tibia and row 4 of metatarsus, S. inerme, row 4 of tibia and metatarsus, S. guaricana, rows 3 and 4 of tibia, and S. spelaeum, row 6 of tibia and row 4 of metatarsus; S. fritzmuelleri and S. pseudovarium have unarmed legs II (DASILVA & GNASPINI 2010). This interesting inter-specific variation could indicate that the leg armature arose independently, and is likely to be used in male agonistic behaviors.…”

“…inerme (Mello-Leitão, 1927) S. guaricana DaSilva & Gnaspini, 2010S. spelaeum (Mello-Leitão, 1933 S. catarina (Machado, Pinto-da-Rocha & Giaretta, 2002) Diagnosis.…”

Foraging, oviposition sites and notes on the natural history of the harvestman Heteromitobates discolor (Opiliones, Gonyleptidae)

“…Nocturnal observations on the foraging behavior in harvestmen are particularly scarce in the literature, with few data on the foraging sites and foraging posture. There are 30-40 species described in the subfamily (DaSilva & Gnaspini 2009), of which 4 have been studied in details and 7 have been the target of some field observations (e.g. Gnaspini 1996;Machado 2002;Willemart & Gnaspini 2004a;.…”

“…Males may also take care of the eggs if females are experimentally removed from the batch (Machado & Oliveira 1998;Buzatto & Machado 2009 -Gnaspini 1996;Machado & Oliveira 1998;Willemart & Gnaspini 2004a;Buzatto et al 2011). Because there is a published phylogeny of the subfamily (DaSilva & Gnaspini 2009), this group is excellent to study the evolution of behavior when using data from several papers. However studies on the natural history of more species are necessary because we often generalize data obtained for a few species for the entire subfamily, which is not necessarily accurate.…”

Four new species of Cosmetus from Panama, with comments on the systematics of the genus (Opiliones: Cosmetidae)

“…Illustrations were made using a Leica MZ APO stereomicroscope with a camera lucida and microscope ZEISS Axioskop 2 Plus. The description of the dorsal armature followed DASILVA & GNASPINI (2009).…”