Chemical and evolutionary analysis of the scent gland secretions of two species of Gonyleptes Kirby, 1819 (Arachnida: Opiliones: Laniatores)

Abstract

The subfamily Gonyleptinae is the second largest in Gonyleptidae, harboring over 100 species.Gonyleptinae is polyphyletic, nestled in the clade K92, and despite its richness, several species of that subfamily have not had their chemicals of the defensive secretions analyzed. Among these are Gonyleptes curticornis (Mello-Leitão, 1940) and G. horridus Kirby, 1819, the latter being particularly important because it is the type species of the genus, which in turn names the subfamily. Gonyleptes horridus is also used in many phylogenetic analyses, be it using morphological or molecular data. The chemical study of the secretions of these two species by GC-MS and NMR 1 H showed the presence of 1-(6-isopropyl-3,4-dihydro-2H-pyran-2-yl)-methylbutanone, 1-(6-isopropyl-3,4-dihydro-2H-pyran-2-yl) isobutanone and 4-methyl-1-hepten-3-one in both species. On the other hand, 4-methyl-1 hexen-3-one, benzaldehyde and 3-octanone were observed only in G. curticornis. Both species are Gonyleptinae and chemical mapping of the group corroborates that vinyl ketones are synapomorphy of K92 and that the compound 1-(6-isopropyl-3,4-dihydro-2H-pyran-2-yl) isobutanone is synapomorphic to G. curticornis and G. horridus, but homoplastic to the genus Sodreana Mello-Leitão, 1922. 1-(6-(1-methyl-propyl)3,4-dihydro-2H-pyran-2yl)2-methylbutanone and 4-methyl-1-hepten3-one is also synapomorphic to G. curticornis and G. horridus, but homoplastic in Moreiranula saprophila.