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.

Anoplotermes-group, enteric valve, Neotropic, taxonomy

The soldierless termites of Amazonia form a dominant group and comprise more than 30% of the termite diversity in neotropical assemblages (Davies 2002, Ackerman et al. 2009, Palin et al. 2011). Although the richness of soldierless taxa is recognized, most have not been described yet (Bourguignon et al. 2015). For example, Palin et al. (2011) list four undescribed Anoplotermes species and 18 undescribed species in 13 undescribed genera from Peru. Originally, all neotropical soldierless termites were placed in the genus Anoplotermes Müller, 1873. Recognition of much greater taxonomic diversity began with Mathews (1977) who described Grigiotermes and Ruptitermes, and Fontes (1986) who described Aparatermes and Tetimatermes. Fontes (1992) provided the first identification key for workers of these five genera. The descriptions of Longustitermes (Bourguignon et al. 2010), Compositermes (Scheffrahn 2013), Amplucrutermes, Humutermes, Hydrecotermes, Patawatermes, and Rubeotermes (Bourguignon et al. 2016), and Disjunctitermes (Scheffrahn et al. 2017) have advanced the classification of neotropical soldierless taxa but many more remain to be described.

Currently, 13 genera and 52 species of Apicotermitinae are known from the Neotropical region (Bourguignon et al. 2010; Krishna et al. 2013; Scheffrahn 2013; Carrijo et al. 2015; Bourguignon et al. 2016; Scheffrahn et al. 2017). For Colombia, Anoplotermes ater, Anoplotermes parvus, Aparatermes silvestrii, Humutermes krishnai, and Patawatermes turricola have been reported (Araujo 1977; Constantino 1998; Bourguignon et al. 2016; Pinzón et al. 2017), and Peru records include Anoplotermes banksi, Anoplotermes pacificus, Disjunctitermes insularis, Rubeotermes jheringi, and Ruptitermes reconditus (Constantino 1998, Bourguignon et al. 2010, Acioli and Constantino 2015, Bourguignon et al. 2016, Scheffrahn et al. 2017). Only 19% of the species of Apicotermitinae of the Neotropics are reported in these two countries.

In this paper Echinotermes biriba gen. n. et sp. n. is described based on the morphology of the worker caste and molecular data.

The specimens were collected and preserved in 75% or 85% ethanol. The dissection of the enteric valve (EV) was done by removing the P2 tube from the worker’s gut and then expelling all the food particles by means of controlled pressure. The tube was immersed in a PVA medium to completely detach the EV from surrounding muscle tissue and cut longitudinally to splay open the EV for mounting in the medium. The mandibles were also submerged in PVA medium. The terminology used for the worker gut follows Sands (1972) and Noirot (2001).

The COI sequence of E. biriba was obtained by DNA extraction and PCR performed by the Canadian Centre for DNA Barcoding following standard high-throughput protocols (deWaard et al. 2008). The PCR employed the primers LepF1 and LepR1 (Hebert et al. 2003) which generated 622 to 652bp of the barcode region of the mitochondrial gene cytochrome c oxidase subunit 1 (COI).

A gene tree was created under Bayesian Inference (BI) using the COI gene. In addition to the sequence of E. biriba, a total of 48 GenBank sequences were used: 34 sequences of neotropical Apicotermitinae (21 species, 13 genera), eight non neotropical Apicotermitinae genera, five non-apicotermitine Termitidae, and one Rhinotermitidae, (Heterotermes crinitus) as the outgroup. Sequences were aligned under MUSCLE algorithm implemented in Geneious v6.1.6 (Biomatters Ltd., Auckland, New Zealand). Substitution model used (GTR+I+G) was selected through the Akaike Information Criterion (AIC) with the software jModelTest2 (Darriba et al. 2012). The XML input files were generated with BEAUti 1.8.0, and the BI was performed with BEAST 1.8.0 (Drummond et al. 2012). A Yule speciation process, with a random starting tree, and relaxed molecular clock was used as tree priors. Four Markov chain Monte Carlo (MCMC) searches were conducted, each one for 15,000,000 generations, and they were combined to search the most probable tree. Convergence and stationarity were assessed with Tracer 1.5 (Rambaut et al. 2014) and the first 600 trees were discarded as burn-in with TreeAnnotator 1.8.0 and visualized using FigTree 1.3.1.

Neotropical soldierless termites have been a taxonomic problem to a large extent because enteric valve (EV) morphology was overlooked. Mathews (1977) showed it was possible to differentiate some New World Apicotermitidae using the EV as had already been done in Africa (Grassé and Noirot 1954, Sands 1972), thus furthering the reclassification of the so-called Anoplotermes-group to this day. As with D. insularis (Scheffrahn et al. 2017), E. biriba is described only from the worker caste with the EV as its most robust diagnostic character.

The Amazon forest contains the greatest diversity of New World termites (Ackerman et al. 2009, Constantino and Cancello 1992), but currently the data show a low diversity of Apicotermitinae compared to other subfamilies such as Nasutitermitinae, Syntermitinae, and Termitinae (Constantino 1991, de Souza and Brown 1994). As new genera and species of neotropical Apicotermitinae are described, the richness of termites, especially in poorly studied countries such as Colombia and Peru will greatly increase.

We want to thank to the Colciencias, Instituto Amazónico de Investigaciones Científicas SINCHI and Expedición BIO project for the financial support in Colombian Amazon. We also thank to Dr. Clara P. Peña-Venegas for coordinating the soil component at SINCHI and for her logistic support on field trips. We heartily thank the reviewers for their help in improving the paper.