No abstract

BackgroundThis paper presents an updated list of soil ants of the Colombian Amazon collected in three different river basins: the Amazon, the Caquetá and the Putumayo. The list includes 10 subfamilies, 60 genera and 218 species collected from TSBF monoliths at four different depths (Litter, 0 - 10 cm, 10 - 20 cm and 20 - 30 cm). This updated list increases considerably the knowledge of edaphic macrofauna of the region, due to the limited published information about soil ant diversity in the Colombian Amazon region.New informationThis is the first checklist of soil ant diversity of the Colombian Amazon region. Six new records of species for Colombia are exposed: Acropyga tricuspis (LaPolla, 2004), Typhlomyrmex clavicornis (Emery, 1906), Typhlomyrmex meire (Lacau, Villemant & Delabie, 2004), Cyphomyrmex bicornis (Forel, 1895), Megalomyrmex emeryi (Forel, 1904) and Myrmicocrypta spinosa (Weber, 1937), most of them corresponding to subterranean ants.

A new Apicotermitinae genus and species Echinotermes biriba is described from workers collected on the Andean-Amazon Piedmont in Colombia and Peru. The enteric valve armature of Echinotermes biriba Castro & Scheffrahn, gen. et sp. n. is a remarkably diagnostic character. A Bayesian phylogenetic analysis using the COI gene and including all other Neotropical Apicotermitinae genera, supports the new genus as a distinct terminal.

Successional processes in abandoned pastures in the Amazon region have been well-documented for the floristic component; however, soil succession has been poorly studied. This study assessed the physical, chemical and biological responses of soils in the Amazon region during the natural succession process in two main landscapes of the Colombian Amazon. Soil data on soil physico–chemical (bulk density, macroaggregates, pH and minerals) and biological (soil macrofauna) composition were evaluated along chronosequence with four successional stages: (i) degraded pastures, (ii) young (10–20-year-old), (iii) middle-age (25–40-year-old) and (iv) mature forests, in two different landscapes (hill and mountain). Individual soil variables and a synthetic indicator of soil quality (GISQ) were evaluated as tools for natural succession monitoring. The results corroborated the negative impact that cattle ranching has on Amazon soils. After 10 years of natural succession, the physico–chemical and biological soil components were widely restored. Less soil compaction and organic carbon occurred in older successional stages. Soil macrofauna richness and density increased along the chronosequence, with an evident association between the macrofauna composition and the macroaggregates in the soil. None of the individual soil properties or the GISQ indicator discriminated among natural succession stages; therefore, new soil quality indicators should be developed to monitor soil quality restoration in natural successions.

We present the description of a new genus and species of soldierless termites from South America. Rustitermes boteroi Constantini, Castro & Scheffrahn, gen. et sp. nov. can be identified by the morphology of the enteric valve, with six slightly asymmetric cushions, each one forming a central pouch made of scales smaller than those between the cushions. The new genus features two characteristic rows of thick bristles on the interior margin of the fore tibia, and is supported by COI molecular sequence data. This species is distributed from Tobago to northern Argentina.

Acorhinotermes Emerson, 1949 is the only Neotropical Rhinotermitine genus with no major soldier. Herein Acorhinotermes claritae Castro & Scheffrahn, sp. nov. is described based on minor soldiers and an alate nymph collected in a secondary rain forest in the Colombian Amazon. The minor soldier of A. claritae Castro & Scheffrahn, sp. nov. has longer mandibular points and it is comparatively smaller than A. subfusciceps. An illustrated key to the minor soldiers of the Neotropical species of Rhinotermitinae is presented.

The neotropical Apicotermitinae is a common and widespread clade of mostly soil-feeding soldierless termites. With few exceptions, species of this group were originally assigned to the genus Anoplotermes Müller, 1873. The application of internal worker morphology coupled with genetic sequencing has recently shed light on the true diversity of this subfamily. Herein, Anoplotermes susanae Scheffrahn, Carrijo & Castro, sp. nov. and four new species in four new genera are described: Hirsutitermes kanzakii Scheffrahn, Carrijo & Castro, gen. nov. et sp. nov., Krecekitermes daironi Scheffrahn, Carrijo & Castro, gen. nov. et sp. nov., Mangolditermes curveileum Scheffrahn, Carrijo & Castro, gen. nov. et sp. nov., and Ourissotermes giblinorum Scheffrahn, Carrijo & Castro, gen. nov. et sp. nov. Worker descriptions are based mainly on worker gut morphology, including the enteric valve, while imagoes were described based on external characters. A Bayesian phylogenetic tree of New World Apicotermitinae was constructed using the complete mitogenome to infer genera relationships and corroborate the taxonomic decisions. Distribution maps and a dichotomic key to the known Neotropical Apicotermitinae genera are provided.

No abstract